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  • Bergstedt, Malin
    Linköping University, Department of Management and Engineering, Production Economics.
    Sales and Operations Planning Framework: How to balance demand and supply for a project-oriented and complex organization operating inthe aerospace and defence industry2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One challenge organizations are facing in all industries is determining the likely events of the future and developing strategies to handle these challenges. Sales and operations planning are a decision-making process and tool that helps organizations to allocate resources not only to handle the challenges but also to take advantage of future conditions by balancing supply and demand. There is only a limited amount of framework and models available today. This project will divulge and reveal a new framework for sales and operations planning which has been developed in collaboration with an organization operating in the aerospace and defence industry. The basis of the framework consists of a monthly five step process that facilitates the organization in making decisions based on long term (five-years) organizational goals and tying them in with project specific needs. Ultimately, this will provide a centralized system in meeting current project specific demands whilst ensuring future operations are not compromised but enhanced. The company’s current sales and operations planning maturity level was evaluated and compared to the developed framework to find gaps of what needs to change for the company to have proactive sales and operations planning.

  • Thorén, Louise
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Petersen, Robert
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Utmaningar för bioregionalism i relation till urbanisering och globalisering2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • Andersson, Kalle
    Linköping University, Department of Management and Engineering, Commercial and Business Law. Linköping University, Faculty of Arts and Sciences.
    Användning av upphovsrättsskyddade verk i politiska sammanhang: Vad får en upphovsman objektivt anses tåla?2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    En upphovsman har enligt 3 § 2 st. upphovsrättslagen (URL) rätt till att dennes verk inte återges till allmänheten med en ändring eller i ett sammanhang som är kränkande för upphovsmannens litterära eller konstnärliga anseende eller egenart. Denna rättighet kallas respekträtten och utgör en del av vad som brukar kallas för en upphovsmans ideella rättigheter. De ideella rättigheterna i Sverige kan härledas tillbaka till Bernkonventionen (BK) som föreskrev att de stater som signerat konventionen var förpliktade att införa nationella bestämmelser om upphovsmäns ideella rättigheter, och däribland rätten till respekt för verket. De bestämmelser som finns i BK utgör ett minimikrav på vad de signerande staterna måste införa och således kan olika länder erbjuda ett olika starkt ideellrättsligt skydd för upphovsmän. Exempelvis är huvudregeln inom fransk rätt att en upphovsman inte behöver tåla några som helst ändringar i dennes verk. Under sommaren år 2018 samlades runt 600 svenska musiker i ett gemensamt upprop mot att politiska partier använde deras verk i sammanhang som musikerna inte kände att de kunde stå bakom. Ett sådant användande kan i teorin utgöra ett intrång i en upphovsmans respekträtt genom att verket används i ett, för upphovsmannens anseende eller egenart, kränkande sammanhang. Vad som kan utgöra ett kränkande sammanhang ska bedömas i varje enskilt fall enligt en objektiv måttstock. Vid en domstolsprocess ska domstolen genom den objektiva måttstocken komma fram till vad en upphovsman vid varje tillfälle får anses tåla. Det kan således sägas att avsaknaden av en generell schablon kring vad som kan utgöra ett kränkande sammanhang medför en rättsosäkerhet för upphovsmän som känner att deras respekträtt har blivit kränkt. Detta eftersom det på förhand inte går att säga vilka typer av sammanhang som en upphovsman objektiv kan sägas ha blivit kränkt av att förekomma i. Den objektiva intrångsbedömningen såsom den är utformad idag kan även anses bidra till en ojämlik bedömning mellan olika verk inom samma konstform, eftersom ett av kriterierna som ska tas hänsyn till är vilken betydelse verket har i ett konstnärligt och litterärt hänseende. En lösning på den ojämlika bedömningen och den fortsatta rättsosäkerheten kan vara att, likt fransk rätt, införa ett generellt ändringsförbud som även kan tillämpas när ett verk sätts i en främmande kontext. En annan lösning hade varit att i rättspraxis fastställa att förekomsten av ett verk i politiska sammanhang alltid ska anses som kränkande för en upphovsmans anseende eller egenart.

  • Imamovic, Arnela
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Management and Engineering, Commercial and Business Law.
    Cash is [no longer] king: is an e-krona the answer?: - a de lege ferenda investigation of the Swedish Riksbank's issuing mandate and other legal callenges in relation to economic effects on the payment market2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    For the past decades, the Swedish public’s payment habits have changed, where the majority of the public has abandoned the old way of making payments, using cash, and instead opted for more modern payment solutions, digital money. The difference between cash and digital money is that cash is physical and only issued by the Riksbank, whereas digital money is created by and stored on accounts at commercial banks.

    The question of what role the state should have on the payment market is an important point of discussion. But it is not categorically a new question; the Swedish government is tackling essentially the same problem today as it has been doing many times before. Today’s problem is to some extent however manifested in a different way. During the 20th century, discussions were held whether or not the Riksbank should have the exclusive right to issue banknotes. It was considered unnecessary, inappropriate and dangerous. The idea that the Riksbank could cover the entire economy’s need for banknotes was, according to the commercial banks, unreasonable. Nonetheless, in 1904 the exclusive right became fait accompli; the government intervened and gave the Riksbank the banknote monopoly. We are now finding ourselves facing a similar situation, where there is a difference of opinion regarding the Riksbank’s role on the payment market. It is therefore nothing new, but rather an expected task for the government, and thus the central bank, to analyze major changes and draw conclusions from them.

    The problem is essentially about cash being phased out by digital means of payment. In order to therefore solve the problem, the Riksbank has started a project to investigate whether or not the Riksbank should issue digital cash to the Swedish public, what the Riksbank calls an e-krona. To introduce an e-krona would be a major step, but for the public to not have access to a government alternative, seeing as cash usage is declining, is also a major step. No decision has been made yet regarding whether the e-krona will be introduced on the market or not. A decision that however has been made, is that the Riksbank is now working on building an e-krona to develop and assess the technique. Nonetheless, an introduction would undoubtedly have consequences for both the Riksbank and the commercial banks, which ultimately means it would have effects on the economy as a whole. What about regulatory aspects; is the Riksbank even allowed to issue an e-krona under current legislation? The answer is affirmative, to a certain extent. There are furthermore many other uncertainties regarding how an e-krona would affect the economy; the Riksbank does not fully answer many of the system issues in its project reports. The question of whether or not it even is up to the Riksbank to make a decision on the matter of an introduction is also questioned by the author in the thesis.

  • Widén, Alexander
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Management and Engineering, Commercial and Business Law.
    Ramavtalets möjligheter och begränsningar: Distinktionen mellan ramavtal och kontrakt2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I Sverige är ramavtal ett effektivt och populärt upphandlingsinstrument. Ramavtalets syfte är att fastställda de villkor som ska gälla för framtida tilldelning av kontrakt och kan användas när en upphandlande myndighet med viss rimlighet kan förutse ett behov och vill planera inför framtida inköp. Ett ramavtal är flexibelt för en upphandlande myndighet eftersom ramavtalet inte måste fastställa en viss volym utan ska ange uppskattad volym om möjligt. Ett kontrakt i upphandlingsrättslig mening avser ett avtal som fastställer de ekonomiska villkoren för en fak-tisk anskaffning av upphandlingsföremålet. Enligt svensk rätt utgör ett kontrakt viss prestation mot viss ersättning.

    Vid upphandling av vissa avtal kan det vara svårt att utläsa huruvida avtalet utgör ett kontrakt eller ramavtal. Enligt kammarrättspraxis sker bedömningen av vilken typ av avtal som förelig-ger i två steg. Det första steget är att undersöka om avtalet utgör viss prestation mot viss ersätt-ning, det vill säga om den upphandlande myndigheten åtar sig att köpa viss kvantitet. I det andra steget görs bedömningen om åtagandet utgör det övervägande värdet i avtalet. Om åta-gandet utgör övervägande del föreligger ett kontrakt, annars föreligger ett ramavtal. Med an-ledning av att ramavtal i regel bara får löpa under fyra år kan upphandlingen behöva göras om ifall avtalet anger en längre löptid än tillåtet. Ett avtal där den upphandlande myndigheten inte fastställer hela volymen riskerar således att utgöra ett ramavtal enligt svensk rätt, trots att den upphandlande myndighetens syfte varit att upphandla ett kontrakt. Bedömningen av huruvida ett kontrakt föreligger kan kritiseras på grund av den svenska rättens snäva distinktion av vad som utgör ett ramavtal respektive kontrakt. Med anledning av att ramavtal finns i olika former finns det anledning till att kontraktbegreppet torde kunna vara vidare än vad svensk rätt ger uttryck för.

    Den svenska rättens uttryck för skillnaden mellan kontrakt och ramavtal behöver numer även ses i ljuset av nytt prejudikat från EU-domstolen. Domstolen fastställde att ett ramavtal måste ange vilken kvantitet som kan komma att bli aktuell beträffande de efterkommande tilldelning-arna av kontrakt. På grund av att volymen ska vara väl underbyggd inskränks ramavtalets flex-ibilitet och distinktionen mot ett kontrakt stramas åt. Domstolens avgörande ger snarare upphov till frågor än svar eftersom domen är oklar i flera avseenden. Domens tillämplighet i praktiken kan därför få konsekvenser för både ramavtalets möjligheter och begränsningar.

  • Mellbye, Hanne
    Linköping University, Department of Management and Engineering, Commercial and Business Law.
    Gold plating vid implementering av EU-direktiv: Nationellt överskridande av miniminivån vid implementering av minimiharmoniseringsdirektiv i ljuset av det svenska genomförandet av IDD2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    När en medlemsstats genomförande av ett EU-direktiv innebär tillförsel av ytterligare bestämmelser vilka medför en förhöjd skyddsnivå i förhållande till direktivet, innebär det utförande av gold plating. Eftersom förfarandet leder till särreglering i förhållande till andra medlemsstater uppstår därmed en konflikt med EU:s harmoniseringsambitioner på den inre marknaden. Det saknas emellertid en allmängiltig definition av gold plating; kommissionens definition är exempelvis snävare än hur definitionen görs gällande i andra fall. Uppsatsen har till syfte att besvara hur gold plating bör definieras och för att ge ytterligare förståelse för begreppet undersöks det svenska genomförandet av IDD, vilket innebar strängare nationella krav i förhållande till direktivet på ett antal områden. IDD beskrivs som ett minimiharmoniseringsdirektiv, men är utformat enligt en lagstiftningsmodell som förutsätter ett enhetligt lagstiftningsgenomförande i medlemsstaterna. IDD kan även relateras till ett flertal rättsområden inom vilka fullharmonisering råder, exempelvis finansmarknadsområdet och direktivet MiFID II.

    I uppsatsens analys framförs ett ställningstagande om att en definition av gold plating bör tydliggöra åtskillnad mellan å ena sidan ett utvidgat tillämpningsområde, å andra sidan tillförsel av materiella krav, eftersom de olika förfarandena innebär olika juridiska problem. Det framhålls dessutom att en bred och deskriptiv definition av gold plating kan vara användbar vid identifiering av direktivs miniminivå. Analysen innebär vidare några kommentarer avseende IDD:s harmoniseringsgrad och en övergripande kategorisering av de avvikelser från miniminivån som har identifierats i genomförandet av direktivet. Därtill framhålls att ett nationellt införande av en norm eller princip som innebär att minimikraven ska vara vägledande vid genomförande av minimiharmoniseringsdirektiv kan strida mot direktivet i det enskilda fallet. Med tanke på EU:s höga regleringsaktivitet och det faktum att medlemsstaternas lagstiftningsmakt har fått ta ett steg tillbaka, kan gold plating mer eller mindre vara en förutsättning för åtgärdade av nationella reformbehov. För att säkerställa att gold plating utförs i enlighet med direktivet och EU-rätten i övrigt, krävs ett tidigare nationellt engagemang och deltagande i den EU-rättsliga beslutsprocessen.

  • Halén, Jakob
    et al.
    Linköping University, Department for Studies of Social Change and Culture.
    Roghem, Johanna
    Linköping University, Department for Studies of Social Change and Culture.
    Oroande fakta om miljöproblem: Om barns oro för miljöförändringar och hur den kan hanteras i undervisningen2018Independent thesis Basic level (professional degree), 240 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna litteraturstudie är att genom tidigare forskning undersöka och förstå lärarens uppdrag kring miljöundervisning i geografi, särskilt med avseende på hur barns oro kan hanteras. I litteraturstudien besvaras syftet genom tre frågeställningar som handlar om varför det är viktigt att undervisa om miljöförändringar, hur barns oro ser ut gällande miljöförändringar samt hur lärare kan hantera barns oro i relation till miljöfrågans komplexitet. Resultatet från litteraturstudien kan sammanfattas som att det är viktigt att undervisa om miljöförändringar för att göra elever medvetna, och att kunskap bidrar till handlingskompetens. Resultaten indikerar också på att barn i hög grad känner oro över olika fenomen kopplade till miljöförändringar, och att undervisning i vissa fall också bidrar till ökad oro om dessa frågor. De undervisningsmetoder som varit framträdande i litteraturen handlar om att ge handlingsberedskap till eleverna, att presentera framgångshistorier i undervisningen samt att använda sig av ett framtidsperspektiv.

    Vid insamling av material utgjorde två områden kriterier för urvalet av litteratur. Dessa var att litteraturen skulle behandla barns oro och att undervisningsmetoder för att hantera oro skulle belysas. Den analysmetod som använts har varit en innehållsanalys, för att hitta mönster och teman, samt likheter och skillnader.

    I litteraturstudien presenteras de olika resultaten utifrån de olika frågeställningarna. Det inleds med att besvara frågan om varför det är viktigt att undervisa om miljöförändringar, för att ge tyngd åt det valda ämnet. Den andra frågeställningen om barns oro innehåller en underrubrik där begreppet coping förklaras. Den sista frågeställningen är indelad i tre underrubriker, som motsvarar de tre undervisningsmetoder som gått att urskilja i forskningen.

    Uppsatsen avslutas med en diskussion av de resultat som framkommit av litteraturstudien. Utifrån de resultaten dras slutsatser kopplade till frågeställningarna. I den avslutande diskussionen påpekas relevansen av detta arbete och de problem som finns gällande undervisning om miljöförändringar. Det diskuteras också om framtida forskningsområden som en förlängning av detta arbete.

  • Public defence: 2019-05-17 10:00 Planck, Linköping
    Tai, Feng-I
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Surface characterization and manipulation of polyampholytic hydrogel coatings2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is dedicated to building up fundamental knowledge about polyampholytic hydrogels, which are developed in our group for anti-fouling purposes. Charge-balanced polymers, where positive and negative charges balance each other, have emerged as interesting candidates for many applications in materials science. We have prepared charge-balanced materials by forming thickness gradients of oppositely charged polyelectrolytes, and use these as model systems for a systematic investigation of the materials and their responses to environmental changes. These hydrogel gradients were sequentially grafted from substrates via surface-initiated photografting and photopolymerization (SIPGP) of cationic and anionic polyelectrolytes. At some thickness ratios, these form a charge-balanced system where the net surface charge is zero, and with certain similarity to zwitterionic systems. The surface charge of the hydrogels is the principal parameter regulating non-specific protein adsorption, and among other things, we demonstrate that the position of the fouling-resistant charge-neutral region can be manipulated upon pH changes. The chemical compositions of the hydrogel gradients were characterized by microscopic infrared spectroscopy. Optical analysis by spectroscopic ellipsometry and imaging surface plasmon resonance were used to monitor the swelling of the hydrogel films, and protein adsorption onto these in real-time. Surface forces, i.e. the interactions with the hydrogels from an intermolecular perspective, which are related mainly to electrostatic and steric forces, were probed by direct force measurement using atomic force microscopy. Force curves were used to determine the surface charge distribution over the hydrogels, and to indicate the correlation between surface charge and protein adsorption. In the later work, hydrogel gradients were patterned as arrayed spots. Their thicknesses and surface roughness provide further information about the polymer structure and provides a basis for relating ellipsometric swelling profiles to thicknesses as obtained by atomic force microscopy. Finally, it is demonstrated how charged hydrogel films can be used as spacers to tune the optimum distance between silver nanoparticles and fluorophores for metal-enhanced fluorescence (MEF). The aim of this work is to understand polyampholytic hydrogels from various perspectives: surface charges and their distribution, the polymer structure, and surface interactions. The knowledge and experience obtained contribute to the general understanding of zwitterionic materials, and to the development of anti-fouling coatings, optical sensing platforms and other applications of charge-balanced hydrogels.

    List of papers
    1. Lateral Control of Protein Adsorption on Charged Polymer Gradients
    Open this publication in new window or tab >>Lateral Control of Protein Adsorption on Charged Polymer Gradients
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    2009 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, no 6, p. 3755-3762Article in journal (Refereed) Published
    Abstract [en]

    This work describes the fabrication, characterization, and protein adsorption behavior of charged polymer gradients. The thin gradient films were fabricated by a two-step technique using UV-initiated free-radical polymerization in a reactor with a moving shutter. A homogeneous layer of cationic poly(2-aminoethyl methacrylate hydrochloride) was first formed, followed by a layer of oppositely charged poly(2-carboxyethyl acrylate) with a continuously increasing thickness. Adsorption from protein solutions as well as human blood plasma was investigated by imaging surface plasmon resonance and infrared microscopy. The results showed excessive protein adsorption in the areas where one of the polymers dominated the composition, while there was a clear minimum at an intermediate position of the gradient. The charge of the surface was estimated by direct force measurements and found to correlate well with the protein adsorption, showing the lowest net charge in the same area as the protein adsorption minimum. We therefore hypothesize that a combination of the charged polymers, in the right proportions, can result in a protein-resistant surface due to balanced charges.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-17501 (URN)10.1021/la803443d (DOI)
    Available from: 2009-03-27 Created: 2009-03-27 Last updated: 2019-04-24
    2. pH-control of the protein resistance of thin hydrogel gradient films
    Open this publication in new window or tab >>pH-control of the protein resistance of thin hydrogel gradient films
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    2014 (English)In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 10, no 32, p. 5955-5964Article in journal (Refereed) Published
    Abstract [en]

    We report on the preparation and characterization of thin polyampholytic hydrogel gradient films permitting pH-controlled protein resistance via the regulation of surface charges. The hydrogel gradients are composed of cationic poly(2-aminoethyl methacrylate hydrochloride) (PAEMA), and anionic poly(2-carboxyethyl acrylate) (PCEA) layers, which are fabricated by self-initiated photografting and photopolymerization (SIPGP). Using a two-step UV exposure procedure, a polymer thickness gradient of one component is formed on top of a uniform layer of the oppositely charged polymer. The swelling of the gradient films in water and buffers at different pH were characterized by imaging spectroscopic ellipsometry. The surface charge distribution and steric interactions with the hydrogel gradients were recorded by direct force measurement with colloidal-probe atomic force microscopy. We demonstrate that formation of a charged polymer thickness gradient on top of a uniform layer of opposite charge can result in a region of charge-neutrality. This charge-neutral region is highly resistant to non-specific adsorption of proteins, and its location along the gradient can be controlled via the pH of the surrounding buffer. The pH-controlled protein adsorption and desorption was monitored in real-time by imaging surface plasmon resonance, while the corresponding redistribution of surface charge was confirmed by direct force measurements.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2014
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-110502 (URN)10.1039/c4sm00833b (DOI)000340474400011 ()24987939 (PubMedID)
    Note

    Funding Agencies|European Commission [NMP-CT-2005-011827]; European Community [237997]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

    Available from: 2014-09-12 Created: 2014-09-12 Last updated: 2019-04-24
    3. Interaction Forces on Polyampholytic Hydrogel Gradient Surfaces
    Open this publication in new window or tab >>Interaction Forces on Polyampholytic Hydrogel Gradient Surfaces
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    2019 (English)In: ACS Omega, ISSN 2470-1343, Vol. 4, no 3, p. 5670-5681Article in journal (Refereed) Published
    Abstract [en]

    Rational design and informed development of nontoxic antifouling coatings requires a thorough understanding of the interactions between surfaces and fouling species. With more complex antifouling materials, such as composites or zwitterionic polymers, there follows also a need for better characterization of the materials as such. To further the understanding of the antifouling properties of charge-balanced polymers, we explore the properties of layered polyelectrolytes and their interactions with charged surfaces. These polymers were prepared via self-initiated photografting and photopolymerization (SIPGP); on top of a uniform bottom layer of anionic poly(methacrylic acid) (PMAA), a cationic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) thickness gradient was formed. Infrared microscopy and imaging spectroscopic ellipsometry were used to characterize chemical composition and swelling of the combined layer. Direct force measurements by colloidal probe atomic force microscopy were performed to investigate the forces between the polymer gradients and charged probes. The swelling of PMAA and PDMAEMA are very different, with steric and electrostatic forces varying in a nontrivial manner along the gradient. The gradients can be tuned to form a protein-resistant charge-neutral region, and we demonstrate that this region, where both electrostatic and steric forces are small, is highly compressed and the origin of the protein resistance of this region is most likely an effect of strong hydration of charged residues at the surface, rather than swelling or bulk hydration of the polymer. In the highly swollen regions far from charge-neutrality, steric forces dominate the interactions between the probe and the polymer. In these regions, the SIPGP polymer has qualitative similarities with brushes, but we were unable to quantitatively describe the polymer as a brush, supporting previous data suggesting that these polymers are cross-linked.

    Place, publisher, year, edition, pages
    American Chemical Society, 2019
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-156495 (URN)10.1021/acsomega.9b00339 (DOI)
    Available from: 2019-04-24 Created: 2019-04-24 Last updated: 2019-04-24
  • Knuthammar, Julia
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Grönqvist, Petra
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Digitalt berättande och dess inverkan på grundskoleelevers skrivförmågor: – En systematisk litteraturstudie2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Digitalt berättande har blivit en del av undervisningen i svenska de senaste åren. Än så länge verkar dock ingen omfattande forskning ha bedrivits i Sverige om hur arbetet med detta påverkar elevers skrivande. Syftet med denna systematiska litteraturstudie var att undersöka digitalt berättande och dess inverkan på grundskoleelevers skrivförmågor. Detta gjordes utifrån frågeställningen: På vilket sätt inverkar digitalt berättande på de kognitiva förmågorna i skrivprocessen?

    För att besvara studiens syfte och frågeställning insamlades totalt elva vetenskapligt granskade artiklar som presenterade empirisk data. Dessa hittades främst genom databaserna Scopus, ERIC och sökmotorn UniSearch.

    Resultatet visar att digitalt berättande kan ha en positiv inverkan på flera kognitiva förmågor som är involverade i skrivprocessen. Exempelvis påverkades förmågan att tänka kreativt, planera, och kontrollera sitt skrivande. Även förmåga att hantera språket ur ett grammatiskt perspektiv och budskapsförmedling påverkades. Utöver detta diskuteras möjliga förklaringar till att digitalt berättande skulle kunna bidra till att utveckla dessa förmågor. De förklaringar som lyfts handlar främst om att digitalt berättande som arbetssätt främjar elevsamarbete och är motivationshöjande. Forskningen verkar vara samstämmig i att digitalt berättande kan ha positiv inverkan på elevers skrivande. För att kunna dra mer slutsatser och utöka kunskap om detta anser vi dock att det finns behov av vidare forskning framförallt i skolans tidiga år och utifrån svensk kontext.

  • Public defence: 2019-05-23 09:00 Hugo Theorell, Linköping
    Niward, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology, Infection and Inflammation. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Infectious Diseases.
    Towards individualised treatment of tuberculosis2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Each year, around 10 million of individuals develop active tuberculosis (TB). Worldwide, TB is the leading cause of death from an infectious agent surpassing both malaria and HIV. Current treatment regimens are long and therefore encompass a risk of nonadherence and development of acquired drug-resistance, reflected in the increase of multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. Indeed, this calls for prudent use of existing TB drugs and improvement of TB treatment strategies. The aim of this thesis was to investigate the current drug susceptibility testing (DST) breakpoints for Mycobacterium tuberculosis (M. tuberculosis), the pharmacokinetics and pharmacodynamics (PK/PD) of TB treatment and to explore the role of therapeutic drug monitoring (TDM) for optimising TB treatment.

    Drug resistance in M. tuberculosis is expressed over a continuous scale and for some drugs it may be identified as low- and high-level resistance. This has been poorly reflected in currently used binary susceptibility breakpoints for TB drugs. Results from genome sequencing and phenotypic DST of ofloxacin and levofloxacin were compared in study I and current breakpoints were found to misclassify up to 25% of M. tuberculosis isolates with resistance mutations in gyrA as susceptible to fluoroquinolones. This finding may have implications for the classification of XDR-TB, treatment of MDR-TB and the evaluation of fluoroquinolones in clinical studies.

    Study II was a prospective cohort study of susceptible TB in Sweden, where drug concentrations of first-line TB drugs were measured along with the susceptibility level of the bacteria defined by the minimum inhibitory concentration (MIC) of M. tuberculosis. First-line drug concentrations below the reference range (16-42%) were common and most pronounced for rifampicin (13/31, 42%). An exploratory investigation of PK/PD parameters displayed a wide distribution of ratios between drug exposures and MICs. Rifampicin exhibited higher level of individual fluctuations over time during TB treatment compared with isoniazid. In study III the plasma drug concentrations of rifampicin were compared to the tuberculosis drug activity assay (TDA) and results showed that rifampicin drug levels, but not drug levels of the other first-line drugs, correlated with TDA. Patients with rifampicin drug levels below 8 mg/L had significantly lower median TDA. This finding supports the use of TDA as a potential indicator for low rifampicin exposure in resource-constrained settings without access to drug concentration analysis. The study design in study II has been further developed in study IV, which is a prospective cohort study of MDR-TB in China, where drug exposure will be explored in relation to individual bacterial MIC and measurements of treatment outcome.

    In summary, the work in this thesis emphasises the importance of reliable DST of M. tuberculosis and the need to re-evaluate the currently used breakpoints. Therapeutic drug monitoring (TDM) based on drug concentrations and MICs is a useful tool to avoid suboptimal drug exposure and to individualise TB treatments. Such strategies may improve treatment regimens and avoid further development of resistance.

    List of papers
    1. Susceptibility testing breakpoints for Mycobacterium tuberculosis categorize isolates with resistance mutations in gyrA as susceptible to fluoroquinolones: implications for MDR-TB treatment and the definition of XDR-TB.
    Open this publication in new window or tab >>Susceptibility testing breakpoints for Mycobacterium tuberculosis categorize isolates with resistance mutations in gyrA as susceptible to fluoroquinolones: implications for MDR-TB treatment and the definition of XDR-TB.
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    2016 (English)In: Journal of Antimicrobial Chemotherapy, ISSN 0305-7453, E-ISSN 1460-2091, Vol. 71, no 2, p. 333-338Article in journal (Refereed) Published
    Abstract [en]

    OBJECTIVES: Fluoroquinolones (FQs) are important in the treatment of MDR-TB and in the definition of XDR-TB. Our objective was to investigate how discrepancies in the phenotypic and genotypic methods for antimicrobial susceptibility testing could affect the interpretation of antimicrobial susceptibility test results.

    METHODS: We analysed MICs of ofloxacin and levofloxacin in Middlebrook 7H10 broth (7H10) as well as sequencing of the quinolone resistance-determining region of the gyrA gene and the MTBDRsl assay in 75 resistant isolates, including MDR and XDR strains of Mycobacterium tuberculosis.

    RESULTS: Among 75 resistant isolates, 27 had mutations associated with FQ resistance. Among isolates with resistance mutations in gyrA, 26% (seven of 27) were susceptible to levofloxacin and ofloxacin by phenotypic testing at 1 mg/L and 2 mg/L. The most common mutation was in codon 94 and these isolates had significantly increased MICs of levofloxacin (2-8 mg/L) compared with isolates with mutations in codon 90 (0.25-2 mg/L, P < 0.05). The sensitivity and specificity for the MTBDRsl assay compared with gyrA sequencing were 96% and 98%, respectively.

    CONCLUSION: Current critical concentrations may classify up to 26% of isolates with gyrA mutations as susceptible to FQs due to a close relationship between susceptible and resistant populations. These results should be considered while improving clinical breakpoints for M. tuberculosis and may have an impact on the definition of XDR-TB.

    National Category
    Infectious Medicine
    Identifiers
    urn:nbn:se:liu:diva-124557 (URN)10.1093/jac/dkv353 (DOI)000372427600008 ()26538509 (PubMedID)
    Note

    Funding agencies: Heart and Lung Foundation; Swedish Society of Antimicrobial Chemotherapy (SSAC); Swedish Medical Association; Marianne and Marcus Wallenberg Foundation

    Available from: 2016-02-03 Created: 2016-02-03 Last updated: 2019-04-24
    2. Distribution of plasma concentrations of first-line anti-TB drugs and individual MICs: a prospective cohort study in a low endemic setting
    Open this publication in new window or tab >>Distribution of plasma concentrations of first-line anti-TB drugs and individual MICs: a prospective cohort study in a low endemic setting
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    2018 (English)In: Journal of Antimicrobial Chemotherapy, ISSN 0305-7453, E-ISSN 1460-2091, Vol. 73, no 10, p. 2838-2845Article in journal (Refereed) Published
    Abstract [en]

    Background: Therapeutic drug monitoring (TDM) could improve current TB treatment, but few studies have reported pharmacokinetic data together with MICs. Objectives: To investigate plasma concentrations of rifampicin, isoniazid, pyrazinamide and ethambutol along with MICs. Methods: Drug concentrations of rifampicin, isoniazid, pyrazinamide and ethambutol were analysed pre-dose and 2, 4 and 6 h after drug intake at week 2 in 31 TB patients and MICs in BACTEC 960 MGIT were determined at baseline. The highest plasma concentrations at 2, 4 and 6 h post-dose (C-high) were determined, as well as estimates of C-high/MIC and area under the concentration-time curve (AUC(0-6))/MIC including the corresponding ratios based on calculated free-drug concentrations. This trial was registered at www.clinicaltrials.gov (NCT02042261). Results: After 2 weeks of treatment, the median C-high values for rifampicin, isoniazid, pyrazinamide and ethambutol were 10.0, 5.3, 41.1 and 3.3 mg/L respectively. Lower than recommended drug concentrations were detected in 42% of the patients for rifampicin (amp;lt;8 mg/L), 19% for isoniazid (amp;lt;3 mg/L), 27% for pyrazinamide (amp;lt;35 mg/L) and 16% for ethambutol (amp;lt;2 mg/L). The median Chigh/MIC values for rifampicin, isoniazid, pyrazinamide and ethambutol were 164, 128, 1.3 and 2.5, respectively, whereas the AUC(0-6)/MIC was 636 (range 156-2759) for rifampicin and 351 (range 72-895) for isoniazid. Conclusions: We report low levels of first-line TB drugs in 16%-42% of patients, in particular for rifampicin. There was a wide distribution of the ratios between drug exposures and MICs. The future use of MIC determinations in TDM is dependent on the development of a reference method and clinically validated pharmacokinetic/pharmacodynamic targets.

    Place, publisher, year, edition, pages
    OXFORD UNIV PRESS, 2018
    National Category
    Pharmaceutical Sciences
    Identifiers
    urn:nbn:se:liu:diva-153707 (URN)10.1093/jac/dky268 (DOI)000452914200032 ()30124844 (PubMedID)
    Note

    Funding Agencies|Research Council of Southeast Sweden; Region of Ostergotland; Marianne and Marcus Wallenberg Foundation; Swedish Heart and Lung Foundation; Swedish Research Council; Stockholm County Council [ALF20160331]

    Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-04-24
    3. Plasma Levels of Rifampin Correlate with the Tuberculosis Drug Activity Assay
    Open this publication in new window or tab >>Plasma Levels of Rifampin Correlate with the Tuberculosis Drug Activity Assay
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    2018 (English)In: Antimicrobial Agents and Chemotherapy, ISSN 0066-4804, E-ISSN 1098-6596, Vol. 62, no 5, article id e00218-18Article in journal (Refereed) Published
    Abstract [en]

    The plasma tuberculosis drug activity (TDA) assay may be an alternative tool for therapeutic drug monitoring in resource-limited settings. In tuberculosis (TB) patients (n = 30), TDA and plasma levels of first-line drugs were analyzed 2 h post-dose, 2 weeks after treatment initiation. Patients with plasma levels of rifampin lower than 8 mg/liter had a significantly lower median TDA (1.40 versus 1.68, P = 0.0013). TDA may be used to identify TB patients with suboptimal rifampin levels during TB treatment.

    Place, publisher, year, edition, pages
    AMER SOC MICROBIOLOGY, 2018
    Keywords
    pharmacokinetics; Mycobacterium tuberculosis; rifampin; isoniazid
    National Category
    Pharmacology and Toxicology
    Identifiers
    urn:nbn:se:liu:diva-147915 (URN)10.1128/AAC.00218-18 (DOI)000431341200022 ()29483112 (PubMedID)
    Note

    Funding Agencies|Research Council of Southeast Sweden (FORSS); Marianne and Marcus Wallenberg Foundation; Swedish Heart and Lung Foundation; Region of Ostergotland, Sweden; Swedish Research Council

    Available from: 2018-05-23 Created: 2018-05-23 Last updated: 2019-04-24
    4. Plasma concentrations of second-line antituberculosis drugs in relation to minimum inhibitory concentrations in multidrug-resistant tuberculosis patients in China: a study protocol of a prospective observational cohort study
    Open this publication in new window or tab >>Plasma concentrations of second-line antituberculosis drugs in relation to minimum inhibitory concentrations in multidrug-resistant tuberculosis patients in China: a study protocol of a prospective observational cohort study
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    2018 (English)In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 8, no 9, article id e023899Article in journal (Refereed) Published
    Abstract [en]

    Introduction Individualised treatment through therapeutic drug monitoring (TDM) may improve tuberculosis (TB) treatment outcomes but is not routinely implemented. Prospective clinical studies of drug exposure and minimum inhibitory concentrations (MICs) in multidrug-resistant TB (MDR-TB) are scarce. This translational study aims to characterise the area under the concentration-time curve of individual MDR-TB drugs, divided by the MIC for Mycobacterium tuberculosis isolates, to explore associations with markers of treatment progress and to develop useful strategies for clinical implementation of TDM in MDR-TB. Methods and analysis Adult patients with pulmonary MDR-TB treated in Xiamen, China, are included. Plasma samples for measure of drug exposure are obtained at 0, 1, 2, 4, 6, 8 and 10 hours after drug intake at week 2 and at 0, 4 and 6 hours during weeks 4 and 8. Sputum samples for evaluating time to culture positivity and MIC determination are collected at days 0, 2 and 7 and at weeks 2, 4, 8 and 12 after treatment initiation. Disease severity are assessed with a clinical scoring tool (TBscore II) and quality of life evaluated using EQ-5D-5L. Drug concentrations of pyrazinamide, ethambutol, levofloxacin, moxifloxacin, cycloserine, prothionamide and para-aminosalicylate are measured by liquid chromatography tandem-mass spectrometry and the levels of amikacin measured by immunoassay. Dried blood spot on filter paper, to facilitate blood sampling for analysis of drug concentrations, is also evaluated. The MICs of the drugs listed above are determined using custom-made broth microdilution plates and MYCOTB plates with Middlebrook 7H9 media. MIC determination of pyrazinamide is performed in BACTEC MGIT 960. Ethics and dissemination This study has been approved by the ethical review boards of Karolinska Institutet, Sweden and Fudan University, China. Informed written consent is given by participants. The study results will be submitted to a peer-reviewed journal. Trial registration number NCT02816931; Pre-results.

    Place, publisher, year, edition, pages
    BMJ Publishing Group Ltd, 2018
    Keywords
    tuberculosis; clinical pharmacology; public health; microbiology
    National Category
    Pharmaceutical Sciences
    Identifiers
    urn:nbn:se:liu:diva-153393 (URN)10.1136/bmjopen-2018-023899 (DOI)000450417800153 ()30287613 (PubMedID)2-s2.0-85054436449 (Scopus ID)
    Note

    Funding Agencies|Swedish Heart Lung Foundation [20150508]; Swedish National Research Council [540-2013-8797]; National Research Foundation of China [81361138019]

    Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2019-04-24Bibliographically approved
  • Olovsson, Weine
    et al.
    Linköping University, National Supercomputer Centre (NSC). Linköping University, Faculty of Science & Engineering.
    Mizoguchi, Teruyasu
    Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
    Magnuson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Kontur, Stefan
    Physics Department and IRIS Adlershof, Humboldt-Universität zu Berlin, Zum Großen Windkanal 6, 12489 Berlin, Germany.
    Hellman, Olle
    Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, United States / Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States.
    Tanaka, Isao
    Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
    Draxl, Claudia
    Physics Department and IRIS Adlershof, Humboldt-Universität zu Berlin, Zum Großen Windkanal 6, 12489 Berlin, Germany / European Theoretical Spectroscopy Facility (ETSF.
    Vibrational Effects in X-ray Absorption Spectra of Two-Dimensional Layered Materials2019In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 15, p. 9688-9692Article in journal (Refereed)
    Abstract [en]

    With the examples of the C K-edge in graphite and the B K-edge in hexagonal boron nitride, we demonstrate the impact of vibrational coupling and lattice distortions on the X-ray absorption near-edge structure (XANES) in two-dimensional layered materials. Theoretical XANES spectra are obtained by solving the Bethe–Salpeter equation of many-body perturbation theory, including excitonic effects through the correlated motion of the core hole and excited electron. We show that accounting for zero-point motion is important for the interpretation and understanding of the measured X-ray absorption fine structure in both materials, in particular for describing the σ*-peak structure.

  • Lidén, Gustav
    et al.
    Institutionen för samhällsvetenskap, Avdelningen för statsvetenskap, Mittuniversitetet.
    Nyhlén, Jon
    Institutionen för samhällsvetenskap, Avdelningen för statsvetenskap, Mittuniversitetet.
    Wallman-Lundåsen, Susanne
    Institutionen för samhällsvetenskap, Avdelningen för statsvetenskap, Mittuniversitetet.
    Engagemang och motivation bland politiker i Västernorrlands landstingsfullmäktige2012Report (Other academic)
    Abstract [sv]

    Det har uppdragits åt avdelningen för statsvetenskap vid Mittuniversitetet att undersöka förutsättningarna för förtroendevalda vid landstinget i Västernorrland. För att ha möjlighet att besvara dessa frågor har en enkät genomförts som riktat sig till både ordinarie ledamöter såväl som ersättare i landstingsfullmäktige i Västernorrland. Syftet med rapporten kan sammanfattas till att redogöra för det engagemang och den motivation politikerna i landstingsfullmäktiges uppvisar inför sina uppdrag som förtroendevalda samt att kartlägga behovet av eventuella kompetensutvecklingsinsatser.

    Enkätens som distribuerades till både ordinarie och ersättande ledamöter utföll med en svarsfrekvens på 55,8 %. Bland bakgrundsstatistiken framgår att drygt 75 % av respondenterna är äldre än 50 år och att 96,5 % av de tillfrågade är uppväxta i Sverige. När det gäller utbildningsnivå visar enkäten att politikerna i landstingsfullmäktige i allmänhet är mer välutbildade än svensken i genomsnitt. 55 % är högskole- eller universitetsutbildade medan siffran för riket är knappat 33 %. Av samtliga tillfrågade svarar knappt 20 % att de utöver uppdraget i fullmäktige inte har något annat förtroendeuppdrag i landstinget. Här existerar dock stora skillnader mellan de som är ersättande ledamöter och ordinarie. Bland de sistnämnda är det endast ett fåtal som inte har ytterligare uppdrag än i fullmäktige. Räknar man antalet politiska uppdraget utöver landstingsfullmäktige redogör de ordinarie ledamöterna att de har nästan två (1,79) till inom landstingets organisation och dessutom 2,56 utöver landstingets organisation. I medeltal har de tillfrågade lång politisk erfarenhet men denna härstammar framförallt utanför landstinget.

    Det finns olika skäl till att vara politiskt aktiv. Bland de tillfrågade är faktorer som möjligheten att kunna påverka och förändra, för att det är en medborgerlig plikt och för att det är utvecklande för den enskilda viktigast. Få anger att de är politiskt aktiva p.g.a. att de är uppvuxna i en politisk miljö eller för att kunna avancera och göra politisk karriär. Den tidsåtgång man bedömer för sitt förtroendeuppdrag, inklusive restid, varierar relativt mycket. I allmänhet kan man dock säga att en majoritet menar att de lägger ned upp till 10 timmar varje vecka på sitt uppdrag som förtroendevald men ju fler politiska uppdrag man innehar desto mer tid spenderar man.

    En knapp fjärdedel av de tillfrågade menar att de inte, under förutsättning att de blir omvalda, skulle vilja fortsätta sitt politiska uppdrag i landstingsfullmäktige. Störst ovilja till detta finns i åldersgrupperna mellan 18-34 år samt bland de som är äldre än 65 år där runt 40 % eller mer inte kan tänka sig det. När det gäller att funderingar kring att avsluta sitt förtroendeuppdrag i förtid säger sig ungefär 10 % överväga detta. Bland de delar av landstinget som de tillfrågade menar har störst inflytande över landstingets politiska verksamhet toppar landstingsstyrelsen följda av tjänstemännen. Det minsta inflytandet menar man att medborgarna har. Samtidigt är de tillfrågade av uppfattningen att landstingsstyrelsen också är mest kunniga i frågor som rör landstinget och nästan 30 % menar även att detta organ borde ges än större inflytande. Detsamma gäller för nämnderna och medborgarna medan många är av uppfattningen att tjänstemännen och journalistkåren bör ha ett minskat inflytande.

    Rätt kompetens och erfarenhet är en förutsättning för att fullgöra sitt förtroendeuppdrag på ett tillfredsställande sätt. I allmänhet menar de tillfrågade att man har detta även om det varierar mellan olika typer av ämnesområden. På frågan om vad man anser sig sakna handlar det om ekonomisk, politisk, kommunikativ och juridisk kompetens.

  • Lundåsen, Susanne
    Mitthögskolan, Östersund.
    Fler föreningar = fler röstare?2001In: Kooperation, socialt kapital och medborgerliga insatser / [ed] Stig Westerdahl, Katarina Friberg, Tom Johnstad, Stockholm: Fören. Kooperativa studier , 2001, p. 201-219Chapter in book (Other academic)
    Abstract [sv]

    en svenska demokratiutredningen tog i sin slutrapport (SOU2000:1) fasta på betydelsen av ett rikt föreningsliv för en fungerande demokrati. Föreningslivet fungerar enligt rapportskri-varna bland annat som skolor i demokrati. Utredarna skriver: ”I föreningslivet utvecklas demokratiskt tänkande. Man lär sig samarbeta och utveckla ett ömsesidigt förtroende för varandra”(SOU 2000:1, s. 196). Denna artikel skall behandla hur förhållandet mellan föreningar och demokratiskt deltagande – i form av röstande – ser ut i Sverige och vad det kan tänkas bero på. Inledningsvis görs en teorigenomgång av kopplingen mellan föreningsliv och demokratiskt deltagande. Sedan redovisas några resultat från korrelationsanalyser mellan valdeltagandet och föreningstätheten. De data som används över de ideella och ekonomiska föreningarna kommer från SCB:s företagsregister, trots att det har vissa brister kan det dock ge en indikation av hur bilden i Sverige ser ut. Resultaten pekar dock inte i en första anblick i den riktning som teorierna kring socialt kapital skulle förutse.

  • Lantz Cronqvist, Mattias
    Linköping University, Department of Computer and Information Science, Human-Centered systems.
    Development and initial validation of a stochastic discrete event simulation to assess disaster preparedness2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Assessing disaster preparedness in a given region is a complex problem. Current methods are often resource intensive and may lack generalizability beyond a specific scenario. Computer-based stochastic simulations may be an additional method but would require systems that are valid, flexible and easy-to-use.

    Emergo Train System (ETS) is an analogue simulation system used for disaster preparedness assessments. This thesis aimed to digitalize the ETS model and develop a stochastic simulation software for improved disaster preparedness assessments.

    Simulation software was developed in C#. The simulation model was based on ETS. Preliminary verification and validation (V&V) tests were performed, including unit and integration testing, trace validation, and a comparison to a prior analogue ETS disaster preparedness assessment exercise.

    The software contains medically validated patients from ETS and is capable of automatically running disaster scenarios with stochastic variations in the injury panorama, available resources, geographical location, and other parameters. It consists of two main programs; an editor where scenarios can be constructed and a simulation system to evaluate the outcome.

    Initial V&V testing showed that the software is reliable and internally consistent. The comparison to the analogue exercise showed a general high agreement in terms of patient outcome. The analogue exercise featured a train derailment with 397 injured, of which 45 patients suffered preventable death. In comparison, the computer simulation ran 100 iterations of the same scenario and indicated that a median of 41 patients (IQR 31 to 44) would suffer a preventable death.

    Stochastic simulation methods can be a powerful complement to traditional capability assessments methods. The developed simulation software can be used for both assessing emergency preparedness with some validity and as a complement to analogue capability assessment exercises, both as input and to validate results. Future work includes comparing the simulation to real disaster outcomes.

  • Lundåsen, Susanne
    Ersta Sköndal högskola, Enheten för forskning om det civila samhället.
    Frivilliga insatser och hälsa2005Book (Other academic)
    Abstract [sv]

    I den genomförda undersökningen har samband mellan hälsa och frivilligt arbete kunnat konstateras. Det är dock, som alltid, svårt att utröna riktningen på sambanden med tvärsnittsstudier. Den teoretiska förklaringen till sambandet mellan frivilliga insatser och hälsa skulle i detta fall gå via det sociala kapitalet som antas vara större hos dem som arbetar frivilligt eller har tillgång till andra typer av informella ideellt baserade nätverk, och att det sociala kapitalet i sin tur påverkar hälsan positivt. De som är frivilligt aktiva har i den genomförda studien i genomsnitt bättre hälsa än de som inte är frivilligt aktiva. Skillnaderna i självskattad hälsa mellan frivilligt aktiva och icke aktiva kan inte förklaras enbart med socioekonomiska skillnader, eftersom frivilligt arbete kvarstår som signifikant i en regressionsmodell där även socioekonomiska faktorer ingår. Andra faktorer som kan kopplas till socialt kapital (såsom tillit) har också en statistiskt signifikant och positiv effekt på den självskattade hälsan. Men bilden av skillnaderna mellan frivilligt aktiva och icke frivilligt aktiva blir något mer komplex om man delar upp dem i mindre grupper.

    Inom gruppen frivilligt aktiva finns det skillnader, där bland andra äldre aktiva har större positiva skillnader i självskattad hälsa än vad yngre har. Bland de yngre finns det inga statistiskt signifikanta skillnader i självskattad hälsa mellan aktiva och icke aktiva. Det finns större hälsoskillnader mellan frivilligt arbetande och icke frivilligt arbetande kvinnor än mellan frivilligt arbetande och icke frivilligt arbetande män. De frivilligt aktiva kvinnorna har i genomsnitt mindre värk i axlar, nacke, rygg, händer, armbågar, ben och knän, medan de frivilligt aktiva männen i vissa fall har mer besvär än vad de icke frivilligt aktiva männen har. En stor del av den generella hälsoskillnaden mellan dem som arbetar frivilligt och dem som inte gör det skulle kunna härledas till de frivilligt arbetande kvinnornas bättre hälsa. Dessa kvinnor har en markant högre utbildningsnivå än de kvinnor som inte arbetar frivilligt, och den är även markant högre än vad genomsnittet bland de frivilligt arbetande männen är. Den högre utbildningsnivån skulle delvis kunna förklara hälsoskillnaderna mellan de frivilligt arbetande kvinnorna och de frivilligt arbetande männen.

    De som är frivilligt aktiva är ofta även aktiva på andra plan, exempelvis genom informella hjälpinsatser för vänner och släktingar som är mer eller mindre omfattande. Även här finns det könsskillnader – kvinnor lägger i genomsnitt ned betydligt mer tid på informellt hjälparbete än vad männen gör. Det finns dock undantag: bland dem som gör betydande informella hjälpinsatser är det vissa som har en sämre hälsa än de övriga aktiva. De som gör de allra största informella hjälpinsatserna, i detta fall för personer med särskilda omsorgsbehov i det egna hushållet, har en i genomsnitt väsentligt sämre självskattad hälsa än de övriga. Denna grupp har antagligen också en mer begränsad möjlighet att engagera sig i aktiviteter utanför det egna hushållet.

    Studien har även berört deltagandet i ideellt baserade nätverk och finner att den självskattade hälsan och den psykiska hälsan i genomsnitt är bättre hos dem som deltar i flertalet ideellt baserade nätverk.

    Teorierna om det sociala kapitalets betydelse finner delvis stöd i denna studie då sambanden mellan de olika formerna av frivilliga insatser och hälsan generellt sett är positiva, vilket var det som hypotetiskt kunde förväntas. Orsakerna till att människor står utanför det organiserade frivilliga arbetet och andra typer av ideella nätverk är antagligen många och de olika faktorernas betydelse för hälsan torde kunna utgöra föremål för en annan studie.

  • Lundåsen, Susanne
    Mid Sweden University College, Sweden / Åbo Akademi University, Finlândia.
    Podemos confiar nas medidas de cofianca? [Can we trust the measurement of trust?]2002In: Opinião Pública, ISSN 0104-6276, E-ISSN 1807-0191, Vol. 8, no 2, p. 304-327Article in journal (Other academic)
    Abstract [en]

    The variable trust has become widely used in the social science research lately and few concepts seem to have attracted so much attention from such a broad variety of academic disciplines. In political science in the theories on social capital and political culture, emphasizing its importance for democracy, trus has been seen as na essential variable for the understanding of societies. In social capital theory the generalized interpersonal trust is often given a particularly important role to initiate virtuous circles of development in the societies. This paper will treat some of the different theories that are connected both to the definition and the effects of generalized trust and then issues connected to the uncertainty of the measurements of generalized trust.

  • Sjödin Fannoun, Madeleine
    et al.
    Linköping University, Department of Social and Welfare Studies.
    Perlman, Sara
    Linköping University, Department of Social and Welfare Studies.
    Demokratisk kompetens: En strukturerad litterturöversikt om värderingar och attityder i årskurs F-32019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • von Essen, Johan
    et al.
    Institutionen för socialvetenskap, Ersta Sköndal Bräcke högskola.
    Wallman Lundåsen, Susanne
    Mittuniversitetet, Avdelningen för samhällsvetenskap.
    Ideellt arbete inom idrottsrörelsen2016Report (Other academic)
    Abstract [sv]

    Omkring hälften av den vuxna befolkningen i det svenska samhället arbetar ideellt, vilket innebär att Sverige har ett tämligen omfattande ideellt arbete. Den enskilt största gruppen av alla dem som arbetar ideellt gör det inom idrottsrörelsen. Eftersom det är så många som arbetar ideellt inom olika idrottsföreningar utgör alla dessa insatser en stor och viktig resurs för idrottsrörelsen. Dessutom innebär de ideella insatserna att idrottsrörelsen vilar på ett folkligt engagemang som gör den till en folkrörelse som är förankrad i det svenska civilsamhället. Att studera ideellt arbete i idrottsrörelsen betyder alltså både att undersöka en betydande andel av det ideella arbete som utförs i det svenska samhället och att studera dem som med sina insatser bidrar till att göra en stor del av idrottsföreningarnas verksamhet möjlig. Detta är också vad denna rapport syftar till genom att beskriva ideellt arbete inom idrottsrörelsen.

    Rapporten kretsar kring ett antal frågor. En första fråga är om de som arbetar ideellt i idrottsorganisationer är typiska för dem som arbetar ideellt eller om de särskiljer de sig på något sätt. En andra fråga är vilken typ av insatser människor gör när de arbetar ideellt i idrottsföreningar. En tredje fråga är vad det är som motiverar dem som arbetar ideellt inom idrottsorganisationer och om det är så att deras motiv skiljer sig från dem som arbetar ideellt i andra ideella organisationer. En fjärde fråga är om idrottsföreningar ställer krav på dem som arbetar ideellt med tanke på allt ansvar som följer av att vara ideell ledare, funktionär eller förtroendevald. En sista fråga är hur de föräldrar som arbetar ideellt i de idrottsföreningar där deras barn idrottar ser på sitt engagemang. Dessa frågor syftar till att närma sig alla dem som arbetar ideellt inom idrottsföreningar och rapporten avslutas med en fördjupad diskussion och ett antal slutsatser.

    Rapporten bygger på den senaste av de fem nationella befolkningsundersökningar om medborgerligt engagemang som Ersta Sköndal högskola gjort sedan 1992. Befolkningsundersökningarna är baserade på ett obundet slumpmässigt urval av befolkningen. Ett antal frågor berörde specifikt erfarenheter av ideellt arbete inom idrottsföreningar och om det egna idrottandet. Förutom befolkningsundersökningen vilar rapporten på ett material som kommer från intervjuer med tio föräldrar som arbetar ideellt i den idrottsförening där deras barn bedriver en individuell idrott. Sammantaget bidrar dessa material med kunskap om det breda engagemang som sker inom idrottsrörelsen.

  • Wallman Lundåsen, Susanne
    Mittuniversitetet, Avdelningen för samhällsvetenskap.
    Föreningsidrottens politiska och demokratiska samband2016In: Föreningen, laget och jaget: 7 perspektiv på idrottens demokratiska effekter / [ed] Christine Dartsch, Johan R Norberg och Johan Pihlblad, Stockholm: Centrum för Idrottsforskning , 2016, p. 47-58Chapter in book (Other academic)
    Abstract [sv]

    Ungefär 30 procent av Sveriges vuxna befolkning är medlemmar i idrottsföreningar. 29 Kan personer som är aktiva inom föreningslivet bidra till en bättre demokrati? Vid en första anblick kan sambandet verka långsökt. Varför skulle opolitiska föreningar ha någon demokratisk betydelse?

    I det här kapitlet undersöker jag om engagemang inom idrottens organisationer bidrar till ökat politiskt deltagande. Vidare granskas i vilken utsträckning organisationerna kontaktar beslutsfattare i syfte att försöka påverka dem i frågor som rör organisationerna. Detta görs i två steg och med hjälp av två enkäter. Den ena är riktad till ett slumpmässigt urval av den svenska befolkningen för att kartlägga det ideella arbetet i Sverige. Den andra är i sin tur riktad till ett slumpmässigt urval av ideella föreningar runtom i landet.

  • Wallman Lundåsen, Susanne
    Mittuniversitetet, Avdelningen för samhällsvetenskap.
    Generell tillit och andel röster på Sverigedemokraterna på kommunnivå i riksdagsvalet 20182018In: Snabbtänkt: reflektioner från valet 2018 av ledande forskare / [ed] Lars Nord, Marie Grusell, Niklas Bolin, Kajsa Falasca, Sundsvall: Mittuniversitetet, Demicom, Sundsvall, Sverige , 2018, p. 52-52Chapter in book (Other (popular science, discussion, etc.))
    Abstract [sv]

    Tidigare undersökningar om vad som utmärker de väljare som röstar på partier som Sverigedemokraterna (SD) har bland annat lyft fram att denna väljargrupp ofta utmärker sig genom att i genomsnitt ha en lägre tillit till människor i största allmänhet. Generell tillit kan sägas spegla  grundinställningen till andra i största allmänhet, med andra ord om misstänksamhet gentemot andra i omvärlden bör råda eller inte....

  • Wallman Lundåsen, Susanne
    Ersta Sköndal Bräcke Högskola / Mittuniversitetet, Avdelningen för samhällsvetenskap.
    Kontakter mellan grupper inom civilsamhällets organisationer2018In: Socialmedicinsk Tidskrift, ISSN 0037-833X, Vol. 95, no 5, p. 528-538Article in journal (Refereed)
    Abstract [sv]

    Studien undersöker i vilken mån det förekommer kontakter mellan grupper som är olika varandra eller inte inom civilsamhällets organisationer och nätverk och om kontakterna samvarierar med lägre fördomar och högre tillit till grupper som är annorlunda en själv. Studien är baserad på en surveyundersökning som är genomförd till ett urval av invånare mellan 18-84 år i 36 svenska kommuner. Totalt deltog drygt 10200 personer i undersökningen. I takt med att mångfalden i samhället ökar framställs arenor som möjliggör kontakter mellan grupper alltmer centrala för den sociala sammanhållningen. Flera tidigare studier pekar på samband mellan exempelvis tillit och ökad livskvalitet, bättre självskattad hälsa. Kontakter mellan grupper inom ramen för civilsamhället förekommer i varierande utsträckning mellan typ av organisationer och kommuner. Resultaten pekar på betydelsen av att kontakterna uppfattas som positiva för tillit och tolerans mellan grupper. Resultaten är i linje med tidigare studier på att yngre är mer benägna att uppfatta kontakter som positiva än äldre.

  • Wallman Lundåsen, Susanne
    Mittuniversitetet, Avdelningen för samhällsvetenskap.
    Kalm, Sara & Anders Uhlin, 2015. Civil Society and the Governance of Development: Opposing Global Institutions. Basingstoke: Palgrave Macmillan2015In: Statsvetenskaplig Tidskrift, ISSN 0039-0747, Vol. 117, no 4, p. 666-669Article, book review (Other academic)
  • Nargund, Vijay
    et al.
    Linköping University, Department of Management and Engineering, Manufacturing Engineering.
    Zamurrad Ahmed, Syed
    Linköping University, Department of Management and Engineering, Manufacturing Engineering.
    3D Layout Scanning for Smart Manufacturing: Method Development and a Study of Future Possibilities2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The term ‘Industry 4.0’ leads to many new possibilities like smart factory which is the amalgamation of manufacturing systems in a network to perform tasks more efficiently. It is becoming more and more important for the companies to develop smart factories and integrate the devices within such a facility to meet the demands of the evolving market. The next generation production systems are designed to share the data within the network, plan, and predict the solution for the future problems.

    One such technology under smart factory is 3D laser scanning resulting in point cloud of the production unit. The traditional way of documenting a layout is usually with the help of 2D computer aided designs which are susceptible to measurement errors and changes that are not updated regularly. With the help of point clouds, an as-is representation of the factories can be recorded which can be easily updated with changes in the real world. With advancements in virtual manufacturing, the need for visualization of the factories is increasing drastically. 3D Laser Scanning is one of the better ways of meeting this need, among many other applications.

    The focus of the thesis had been to create a method document for 3D laser scanning of factories and to discuss the future possibilities of it. The research approach used in this thesis was conducting observational study, interviews and testing of the method. One such future possibility is autonomous scanning and how it would be beneficial for a company like Scania which is developing smart factories. Based on the study carried out during the thesis, a document presenting the method developed is included in the report. The report also points out the applications and benefits of point cloud over traditional layout planning methods.

  • Wallman Lundåsen, Susanne
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Social Sciences.
    Trägårdh, Lars
    Ersta Sköndal Bräcke University College, The Institute for Organisational and Worklife Ethics.
    Civilsamhälle, social sammanhållning och tillit: Rapport till Kommissionen för ett socialt hållbart Stockholm2016Report (Other academic)
    Abstract [sv]

    Stockholms stad har inrättat Kommissionen för ett socialt hållbart Stockholm med uppdraget att analysera skillnader i livsvillkor i kommunen och föreslå åtgärder för att minska skillnader och främja en socialt hållbar utveckling i Stockholm.

    Kommissionens arbete bedrivs av förvaltningsorganisationen inom fyra utpekade utvecklingsområden och ska enligt direktiv vila på vetenskaplig grund och genomföras i samverkan med fristående forskare. De forskare som kopplas till kommissionens arbete ska ta fram vetenskapliga underlag med förslag till åtgärder inom avgränsade fördjupningsområden som bidrar till att stärka den sociala hållbarheten i kommunen. Denna rapport är ett sådant underlag.

    Kommissionen för ett socialt hållbart Stockholm ska beakta forskarnas underlag i framtagandet av delrapporter med egna rekommendationer och åtgärder inom det aktuella fördjupningsområdet. Dessa fördjupningar utarbetas med regelbundenhet fram till slutet av 2017, samtidigt som konkreta åtgärder kan implementeras.

  • Wallman Lundåsen, Susanne
    et al.
    Mittuniversitetet, Avdelningen för samhällsvetenskap.
    von Essen, Johan
    Ersta Sköndal högskola.
    Medborgerligt engagemang: Klassresa eller klassklyfta?2015Report (Other academic)
    Abstract [sv]

    2014 års Demokratiutredning har i uppgift att analysera behovet av och utarbeta förslag till åtgärderför att öka och bredda engagemanget inom den representativa demokratin. Utredningen ska även föreslå åtgärder i syfte att stärka individens möjligheter till delaktighet i och inflytande över det politiska beslutsfattandet mellan de allmänna valen. Inom ramen för ovan beskriva uppgifter ska utredningen bl.a. identifiera samhällsförändringar som kan påverka det demokratiska deltagandet på sikt. Utredningen ska också belysa frågor om det förändrade politiska engagemangs-formerna, däribland ett minskat antal medlemmar i de politiska partierna, färre aktiva medlemmar i de traditionella folkrörelserna, ett mer nätverksbaserat civilsamhälle, ökad användning av internet för politiska aktiviteter och fördjupade skillnader i deltagandet mellan olika samhällsgrupper.

    Johan von Essen och Susanne Wallman Lundåsen har på uppdrag av 2014 års Demokratiutredning skrivit en rapport om omfattningen av det ideella arbetet i Sverige. I rapporten undersöker författarna om det medborgerliga engagemanget i Sverige påverkar vilka som får ökade möjligheter till inflytande över politiskt beslutsfattande. Johan von Essen är docent i systematisk teologi vid Ersta Sköndal Högskola och Susanne Wallman-Lundåsen är docent i statsvetenskap vid Ersta Sköndal Högskola och Mittuniversitetet.

  • Skog, Mårten
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Sivlér, Petter
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Steinvall, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Aili, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Elmasry, Moustafa
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    The Effect of Enzymatic Digestion on Cultured Epithelial Autografts2019In: Cell Transplantation, ISSN 0963-6897, E-ISSN 1555-3892Article in journal (Refereed)
    Abstract [en]

    Severe burns are often treated by means of autologous skin grafts, preferably following early excision of the burnt tissue. In the case of, for example, a large surface trauma, autologous skin cells can be expanded in vitro prior to transplantation to facilitate the treatment when insufficient uninjured skin is a limitation. In this study we have analyzed the impact of the enzyme (trypsin or accutase) used for cell dissociation and the incubation time on cell viability and expansion potential, as well as expression of cell surface markers indicative of stemness. Skin was collected from five individuals undergoing abdominal reduction surgery and the epidermal compartment was digested in either trypsin or accutase. Trypsin generally generated more cells than accutase and with higher viability; however, after 7 days of subsequent culture, accutase-digested samples tended to have a higher cell count than trypsin, although the differences were not significant. No significant difference was found between the enzymes in median fluorescence intensity of the analyzed stem cell markers; however, accutase digestion generated significantly higher levels of CD117- and CD49f-positive cells, but only in the 5 h digestion group. In conclusion, digestion time appeared to affect the isolated cells more than the choice of enzyme.

  • Syssner, Josefina
    Linköping University, Department for Studies of Social Change and Culture, Centre for Municipality Studies – CKS. Linköping University, Faculty of Arts and Sciences.
    Nya visioner för landsbygden2018Collection (editor) (Other academic)
    Abstract [sv]

    NYA VISIONER FÖR LANDSBYGDEN Relationen mellan stad och land är under ständig diskussion. I urbaniseringens tidevarv koncentreras människor, företag och service till städerna. Hur kan landsbygden utvecklas under dessa förutsättningar? Hur bygger vi kreativa och inkluderande samhällen på landsbygden? Hur kan en positiv och inkluderande framtidsvision för framtidens landsbygd? I den här boken ger elva forskare från olika discipliner och lärosäten sina perspektiv på just dessa frågor. Med utgångspunkt i tematiker som globalisering, migration, digitalisering, service, bostadsförsörjning, näringslivsutveckling, lantbruk, klimat, hållbarhet och samskapande fördjupar sig forskarna i landsbygdens förutsättningar och framtid.

  • Sundqvist, Nicolas
    Linköping University, Department of Biomedical Engineering.
    Can you trust your model? A showcase study of validation in 13C metabolic flux analysis2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cellular metabolism is one of the most fundamental systems for any living organisms, involving thousands of metabolites and reactions that forms large interconnected metabolic networks. Proper and comprehensive understanding of the metabolism in human cells has been a field of research for a long time. One of the key parameters in understanding the metabolism are the metabolic fluxes, which are the rates of conversion of metabolic intermediates. Currently, one of the main approaches for determining these fluxes is metabolic flux analysis (MFA), in which isotope-labelled compounds are introduced into the system and measured. Mathematical models are then used to calculate a prediction of the systems flux configuration. However, the current paradigm of MFA lack established methods for validating that a model can accurately predict quantities for which there are no experimental data. In this study, a model for the central human metabolism was created and evaluated with regards to the model’s ability to predict a validation dataset. Further, an uncertainty analysis of these predictions were performed with a prediction profile likelihood analysis. This study has conclusively shown that MFA models can be validated against experimental data that the model has never seen before. Additionally, such model predictions were shown to be observable with a well determined prediction uncertainty. These results shows that a systematic validation of MFA models is possible. This in turn allows for a greater trust to be placed in the models, and in any conclusions that are based on such models.

  • Soames, Kieron
    et al.
    Linköping University, Department of Computer and Information Science.
    Lind, Jonas
    Linköping University, Department of Computer and Information Science.
    Detecting Cycles in GraphQL Schemas2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    GraphQL is a database handling API created by Facebook, that provides an effective al-ternative to REST-style architectures. GraphQL provides the ability for a client to spec-ify exactly what data it wishes to receive. A problem with GraphQL is that the freedomof creating customized requests allows data to be included several times in the response,growing the response’s size exponentially. The thesis contributes to the field of GraphQLanalysis by studying the prevalence of simple cycles in GraphQL schemas. We have im-plemented a locally-run tool and webtool using Tarjan’s and Johnson’s algorithms, thatparses the schemas, creates a directed graph and enumerates all simple cycles in the graph.A collection of schemas was analysed with the tool to collect empirical data. It was foundthat 39.73 % of the total 2094 schemas contained at least one simple cycle, with the averagenumber of cycles per schema being 4. The runtime was found to be on average 11 mil-liseconds, most of which consisted of the time for parsing the schemas. It was found that44 out of the considered schemas could not be enumerated due to containing a staggeringamount of simple cycles. It can be concluded that it is possible to test schemas for cyclicityand enumerate all simple cycles in a given schema efficiently.

  • Public defence: 2019-05-24 13:00 Berzeliussalen, Linköping
    Tobieson, Lovisa
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Surgically Treated Intracerebral Haemorrhage: Pathophysiology and Clinical Aspects2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mortality and morbidity of intracerebral haemorrhage (ICH) is excessively high, and the case fatality rate has not improved in the last decades. Although surgery for ICH can be life-saving, no positive effect on functional outcome has been found in large cohorts of ICH patients. Increased understanding of the pathophysiology of ICH is needed to develop improved treatment strategies.

    In 17 ICH patients, paired cerebral microdialysis (CMD) catheters were inserted in the perihaemorrhagic zone (PHZ) and in normal uninjured cortex at time of surgery. Despite normalisation of cerebral blood flow, a persistent metabolic crisis indicative of mitochondrial dysfunction was detected in the PHZ. This metabolic pattern was not observed in the uninjured cortex.

    CMD was also used to sample proteins for proteomic analysis. A distinct proteome profile that changed over time was found in the PHZ when compared to the seemingly normal, uninjured cortex. However, protein adsorption to CMD membranes, which may interfere with concentration measurements, was substantial.

    Surgical treatment of 578 ICH patients was analysed in a nation-wide retrospective multi-centre study in Sweden over five years. Patients selected for surgery had similar age, pre-operative level of consciousness and co-morbidity profiles, but ICH volume and the proportion of deep-seated ICH differed among the six neurosurgical centres. Furthermore, there was variability in the post-operative care, including the use and duration of intracranial pressure monitoring, cerebrospinal fluid drainage and mechanical ventilation.

    In conclusion, the results of this thesis show that:

    (i) Despite surgical removal of an ICH a metabolic crisis caused by mitochondrial dysfunction, a potential future therapeutic target, persists in the perihaemorrhagic zone.

    (ii-iii) CMD is a valuable tool in ICH research for sampling novel biomarkers using proteomics, which may aid in the development of improved therapeutic interventions. However, caveats of the technique, such as protein adsorption to the CMD membrane, must be considered.

    (iv) The nation-wide study illustrates similar clinical features in patients selected for ICH surgery, but substantial variability in ICH volume and location as well as neurocritical care strategies among Swedish neurosurgical centres. Development of refined clinical guidelines may reduce such intercentre variability and lead to improved functional outcome for ICH patients.  

    List of papers
    1. Persistent Metabolic Disturbance in the Perihemorrhagic Zone Despite a Normalized Cerebral Blood Flow Following Surgery for Intracerebral Hemorrhage.
    Open this publication in new window or tab >>Persistent Metabolic Disturbance in the Perihemorrhagic Zone Despite a Normalized Cerebral Blood Flow Following Surgery for Intracerebral Hemorrhage.
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    2018 (English)In: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    BACKGROUND: We hypothesized that reduced cerebral blood flow (CBF) and/or energy metabolic disturbances exist in the tissue surrounding a surgically evacuated intracerebral hemorrhage (ICH). If present, such CBF and/or metabolic impairments may contribute to ongoing tissue injury and the modest clinical efficacy of ICH surgery.

    OBJECTIVE: To conduct an observational study of CBF and the energy metabolic state in the perihemorrhagic zone (PHZ) tissue and in seemingly normal cortex (SNX) by microdialysis (MD) following surgical ICH evacuation.

    METHODS: We evaluated 12 patients (median age 64; range 26-71 yr) for changes in CBF and energy metabolism following surgical ICH evacuation using Xenon-enhanced computed tomography (n = 10) or computed tomography perfusion (n = 2) for CBF and dual MD catheters, placed in the PHZ and the SNX at ICH surgery.

    RESULTS: CBF was evaluated at a mean of 21 and 58 h postsurgery. In the hemisphere ipsilateral to the ICH, CBF improved between the investigations (36.6 ± 20 vs 40.6 ± 20 mL/100 g/min; P < .05). In total, 1026 MD samples were analyzed for energy metabolic alterations including glucose and the lactate/pyruvate ratio (LPR). The LPR was persistently elevated in the PHZ compared to the SNX region (P < .05). LPR elevations in the PHZ were predominately type II (pyruvate normal-high; indicating mitochondrial dysfunction) as opposed to type I (pyruvate low; indicating ischemia) at 4 to 48 h (70% vs 30%) and at 49 to 84 h (79% vs 21%; P < .05) postsurgery.

    CONCLUSION: Despite normalization of CBF following ICH evacuation, an energy metabolic disturbance suggestive of mitochondrial dysfunction persists in the perihemorrhagic zone.

    Place, publisher, year, edition, pages
    Oxford University Press, 2018
    National Category
    Neurology
    Identifiers
    urn:nbn:se:liu:diva-150994 (URN)10.1093/neuros/nyy179 (DOI)29788388 (PubMedID)
    Available from: 2018-09-10 Created: 2018-09-10 Last updated: 2019-04-17
    2. Dynamic protein changes in the perihaemorrhagic zone of Surgically Treated Intracerebral Haemorrhage Patients
    Open this publication in new window or tab >>Dynamic protein changes in the perihaemorrhagic zone of Surgically Treated Intracerebral Haemorrhage Patients
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    2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 3181Article in journal (Refereed) Published
    Abstract [en]

    The secondary injury cascades exacerbating the initial brain injury following intracerebral haemorrhage (ICH) are incompletely understood. We used dual microdialysis (MD) catheters placed in the perihaemorrhagic zone (PHZ) and in seemingly normal cortex (SNX) at time of surgical ICH evacuation in ten patients (range 26-70 years). Routine interstitial MD markers (including glucose and the lactate/pyruvate ratio) were analysed and remaining microdialysate was analysed by two-dimensional gel electrophoresis (2-DE) and nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS). Two time intervals were analysed; median 2-10 hours post-surgery (time A) and median 68-76 hours post-ICH onset (time B). Using 2-DE, we quantified 232 +/- 31 different protein spots. Two proteins differed between the MD catheters at time A, and 12 proteins at time B (p amp;lt; 0.05). Thirteen proteins were significantly altered between time A and time B in the SNX and seven proteins in the PHZ, respectively. Using nLC-MS/MS ca 800 proteins were identified out of which 76 were present in all samples. At time A one protein was upregulated and two downregulated, and at time B, seven proteins were upregulated, and four downregulated in the PHZ compared to the SNX. Microdialysis-based proteomics is feasible for study of secondary injury mechanisms and discovery of biomarkers after ICH.

    Place, publisher, year, edition, pages
    NATURE PUBLISHING GROUP, 2019
    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:liu:diva-155569 (URN)10.1038/s41598-019-39499-2 (DOI)000459897600115 ()30816204 (PubMedID)
    Note

    Funding Agencies|Swedish Stroke Association (STROKE-Riksforbundet); ALF Grants of Region Ostergotland

    Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-04-17
    3. Differences in neurosurgical treatment of intracerebral haemorrhage: a nation-wide observational study of 578 consecutive patients
    Open this publication in new window or tab >>Differences in neurosurgical treatment of intracerebral haemorrhage: a nation-wide observational study of 578 consecutive patients
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    2019 (English)In: Acta Neurochirurgica, ISSN 0001-6268, E-ISSN 0942-0940Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    Background

    Supratentorial intracerebral haemorrhage (ICH) carries an excessive mortality and morbidity. Although surgical ICH treatment can be life-saving, the indications for surgery in larger cohorts of ICH patients are controversial and not well defined. We hypothesised that surgical indications vary substantially among neurosurgical centres in Sweden.

    Objective

    In this nation-wide retrospective observational study, differences in treatment strategies among all neurosurgical departments in Sweden were evaluated.

    Methods

    Patient records, neuroimaging and clinical outcome focused on 30-day mortality were collected on each operated ICH patient treated at any of the six neurosurgical centres in Sweden from 1 January 2011 to 31 December 2015.

    Results

    In total, 578 consecutive surgically treated ICH patients were evaluated. There was a similar incidence of surgical treatment among different neurosurgical catchment areas. Patient selection for surgery was similar among the centres in terms of patient age, pre-operative level of consciousness and co-morbidities, but differed in ICH volume, proportion of deep-seated vs. lobar ICH and pre-operative signs of herniation (p < .05). Post-operative patient management strategies, including the use of ICP-monitoring, CSF-drainage and mechanical ventilation, varied among centres (p < .05). The 30-day mortality ranged between 10 and 28%.

    Conclusions

    Although indications for surgical treatment of ICH in the six Swedish neurosurgical centres were homogenous with regard to age and pre-operative level of consciousness, important differences in ICH volume, proportion of deep-seated haemorrhages and pre-operative signs of herniation were observed, and there was a substantial variability in post-operative management. The present results reflect the need for refined evidence-based guidelines for surgical management of ICH.

    Place, publisher, year, edition, pages
    Springer, 2019
    Keywords
    Intracerebral haemorrhage, Surgery, Guidelines, Craniotomy, External ventricular drain, Intraventricular haemorrhage
    National Category
    Surgery
    Identifiers
    urn:nbn:se:liu:diva-156370 (URN)10.1007/s00701-019-03853-0 (DOI)30877470 (PubMedID)2-s2.0-85063056347 (Scopus ID)
    Available from: 2019-04-17 Created: 2019-04-17 Last updated: 2019-04-24Bibliographically approved
  • Public defence: 2019-05-17 09:00 Hasselquistsalen, Linköping
    Ward, Liam
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Sex differences in atherosclerosis and exercise effects2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cardiovascular disease (CVD) is the leading cause of death globally, with atherosclerosis being the main cause of cardiovascular diseases. Atherosclerosis is an inflammatory disease of the blood vessel wall, which over time will cause thickening and hardening of the vessel wall. Atherosclerosis can result in catastrophic vascular events, such as myocardial infarction and stroke. There are distinct sex differences in CVD mortality at different ages, before menopause women have a lower mortality of CVD in comparison to men, which equalises after menopause. In addition to sex differences in the incidence of CVD, there are also distinct sex differences in the phenotype of atherosclerotic plaques, with men generally developing more severe and vulnerable plaques that are at risk of rupture.

    This thesis aimed to investigate the sex differences in atherosclerosis, in particular how the proteome and pathophysiology differs. In addition, we sought to investigate the potential benefit of an exercise programme, in reducing CVD risks, using a randomised controlled trial including postmenopausal women.

    Sex differences in atherosclerosis were first investigated via proteomic analysis of human carotid endarterectomy samples. Initially, five intraplaque biopsies were taken from distinct atheroma regions, including; internal control, fatty streak, plaque shoulder, plaque centre, and fibrous cap. Protein extracts from these biopsies were subjected to analysis by mass spectrometry. The novel sampling method was successful in reducing the effect of plaque heterogeneity, a limitation in previous proteomic studies of atherosclerosis, and a number of previously unreported proteins were identified in human carotid atheroma. In addition to this, with the inclusion of multivariate statistical modelling, it was found that 43 proteins significantly discriminated the carotid atheroma between men and women. These proteins were grouped by function, and it was found that atheroma from men was associated with the increased abundance of inflammatory response proteins, including phospholipase-A2 membrane associated and lysozyme C, and atheroma from women was associated with increased abundance of blood coagulation, complement activation, and transport proteins, notably including; antithrombin-III, coagulation factor XII, and afamin. In addition, differences were also ii observed in the abundance of iron metabolism related proteins. These sex differences were further expanded upon from a pathophysiological perspective. Immunohistochemistry stainings of ferritin and transferrin receptor 1 were found significantly increased in the atheroma from men. Moreover, the levels of plasma haemoglobin were also significantly increased in men and were associated with the development of more vulnerable and severe plaque types. The more vulnerable and severe plaque types were also associated with significantly greater macrophage infiltration. In summary, these results are indicative of men developing atheroma with greater inflammation that are more vulnerable, due to increased iron and inflammatory proteins and macrophage infiltration, whereas atheroma from women develop with less inflammation and a more stable phenotype.

    The randomised controlled clinical trial aimed at investigating the effects of resistance training (RT), over a 15-week period, in postmenopausal women. Plasma samples were obtained at week-0 and week-15 of the study period, and analyses were performed primarily using a series of immunoassays. Results showed that women participating in RT, with good compliance, were associated with significant decreases in plasma levels of ferritin, lipids, and inflammatory adipokines. These results suggest that the use of regular RT may be a beneficial intervention in reducing the levels of body iron, lipids, and inflammation, all of which are risk factors for the development of CVD. However, validation studies are required in a larger cohort of postmenopausal women, in addition to the inclusion or complementary studies in middle-aged men.

    In summary, the works included in this thesis further expand on the current knowledge of sex differences in atherosclerosis, and also provides information on the potential of an exercise intervention to beneficially reduces the effects of known risk factors of CVD.

    List of papers
    1. Distinctive proteomic profiles among different regions of human carotid plaques in men and women
    Open this publication in new window or tab >>Distinctive proteomic profiles among different regions of human carotid plaques in men and women
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    2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, no 26231Article in journal (Refereed) Published
    Abstract [en]

    The heterogeneity of atherosclerotic tissue has limited comprehension in proteomic and metabolomic analyses. To elucidate the functional implications, and differences between genders, of atherosclerotic lesion formation we investigated protein profiles from different regions of human carotid atherosclerotic arteries; internal control, fatty streak, plaque shoulder, plaque centre, and fibrous cap. Proteomic analysis was performed using 2-DE with MALDI-TOF, with validation using nLC-MS/MS. Protein mapping of 2-DE identified 52 unique proteins, including 15 previously unmapped proteins, of which 41 proteins were confirmed by nLC-MS/MS analysis. Expression levels of 18 proteins were significantly altered in plaque regions compared to the internal control region. Nine proteins showed site-specific alterations, irrespective of gender, with clear associations to extracellular matrix remodelling. Five proteins display gender-specific alterations with 2-DE, with two alterations validated by nLC-MS/MS. Gender differences in ferritin light chain and transthyretin were validated using both techniques. Validation of immunohistochemistry confirmed significantly higher levels of ferritin in plaques from male patients. Proteomic analysis of different plaque regions has reduced the effects of plaque heterogeneity, and significant differences in protein expression are determined in specific regions and between genders. These proteomes have functional implications in plaque progression and are of importance in understanding gender differences in atherosclerosis.

    Place, publisher, year, edition, pages
    NATURE PUBLISHING GROUP, 2016
    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:liu:diva-129495 (URN)10.1038/srep26231 (DOI)000376554600001 ()27198765 (PubMedID)
    Note

    Funding Agencies|Swedish Heart Lung Foundation; Linkoping University Hospital Research foundation; Swedish Institute; China Scholarship Council

    Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2019-04-17
    2. Proteomics and multivariate modelling reveal sex-specific alterations in distinct regions of human carotid atheroma
    Open this publication in new window or tab >>Proteomics and multivariate modelling reveal sex-specific alterations in distinct regions of human carotid atheroma
    2018 (English)In: Biology of Sex Differences, ISSN 2042-6410, Vol. 9, article id 54Article in journal (Refereed) Published
    Abstract [en]

    BackgroundAtherosclerotic lesions are comprised of distinct regions with different proteomic profiles. Men and women develop differences in lesion phenotype, with lesions from women generally being more stable and less prone to rupture. We aimed to investigate the differences in proteomic profiles between sexes, including distinct lesion regions, to identify altered proteins that contribute to these differences observed clinically.MethodsCarotid endarterectomy samples (ten men/ten women) were obtained, and intraplaque biopsies from three distinct regions (internal control, fatty streak and plaque) were analysed by tandem-mass spectrometry. Multivariate statistical modelling, using orthogonal partial least square-discriminant analysis, was used to discriminate the proteomes between men and women.ResultsMultivariate discriminant modelling revealed proteins from 16 functional groups that displayed sex-specific associations. Additional statistics revealed ten proteins that display region-specific alterations when comparing sexes, including proteins related to inflammatory response, response to reactive oxygen species, complement activation, transport and blood coagulation. Transport protein afamin and blood coagulation proteins antithrombin-III and coagulation factor XII were significantly increased in plaque region from women. Inflammatory response proteins lysozyme C and phospholipase A2 membrane-associated were significantly increased in plaque region from men. Limitations with this study are the small sample size, limited patient information and lack of complementary histology to control for cell type differences between sexes.ConclusionsThis pilot study, for the first time, utilises a multivariate proteomic approach to investigate sexual dimorphism in human atherosclerotic tissue, and provides an essential proteomic platform for further investigations to help understand sexual dimorphism and plaque vulnerability in atherosclerosis.

    Place, publisher, year, edition, pages
    BMC, 2018
    Keywords
    Afamin; Atherosclerosis; Lysozyme C; Mass spectrometry; Serine protease inhibitors; Vulnerability
    National Category
    Medical Genetics
    Identifiers
    urn:nbn:se:liu:diva-153822 (URN)10.1186/s13293-018-0217-3 (DOI)000454616000001 ()30594242 (PubMedID)
    Note

    Funding Agencies|Swedish Heart Lung Foundation; Torsten and Ragnar Soderbergs Foundation; Stroke Foundation; Olle Engkvist Foundation; Swedish Gamla Tjanarinnor Foundation; Linkoping University Hospital Research Fund

    Available from: 2019-01-11 Created: 2019-01-11 Last updated: 2019-04-17
    3. Carotid Atheroma From Men Has Significantly Higher Levels of Inflammation and Iron Metabolism Enabled by Macrophages
    Open this publication in new window or tab >>Carotid Atheroma From Men Has Significantly Higher Levels of Inflammation and Iron Metabolism Enabled by Macrophages
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    2018 (English)In: Stroke, ISSN 0039-2499, E-ISSN 1524-4628, Vol. 49, no 2, p. 419-425Article in journal (Refereed) Published
    Abstract [en]

    Background and Purpose-Men differ from women in the manifestation of atherosclerosis and iron metabolism. Intraplaque hemorrhage and hemoglobin (Hb) catabolism by macrophages are associated with atherosclerotic lesion instability. The study aims were to investigate sex differences in (1) lesion severity in relation to blood Hb, (2) iron homeostasis in human carotid plaques, and (3) macrophage polarization within atheroma. Methods-The carotid artery samples from 39 men and 23 women were immunostained with cell markers for macrophages, smooth muscle cells, ferritin, and TfR1 (transferrin receptor 1), which were further analyzed according to sex in relation to iron, Hb, and lipids in circulation. Additionally, samples of predefined regions from human carotid atherosclerotic lesions, including internal controls, were used for proteomic analysis by mass spectrometry. Results-Male patients, compared with women, had larger necrotic cores and more plaque rupture, which were associated with higher levels of Hb. Atheroma of male patients had significantly higher levels of Hb in circulation and CD68 macrophages, ferritin, and TfR1 in lesions. CD68 macrophages were significantly correlated with ferritin and TfR1. Plaques from male patients comparatively possessed higher levels of inflammatory macrophage subsets, CD86 (M1) and CD163 (M2), but lower levels of STF (serotransferrin) and HPX (hemopexin). Conclusions-Male patients with carotid atheroma had more advanced and ruptured lesions associated with significantly higher levels of inflammatory macrophage infiltration and high iron stores in the blood and in their plaques. These findings help to understand sex differences and iron metabolism in atherosclerosis and factors related to atheroma progression.

    Place, publisher, year, edition, pages
    LIPPINCOTT WILLIAMS & WILKINS, 2018
    Keywords
    atherosclerosis; ferritins; hemoglobins; hemopexin; macrophages; male
    National Category
    Neurology
    Identifiers
    urn:nbn:se:liu:diva-144876 (URN)10.1161/STROKEAHA.117.018724 (DOI)000422928000035 ()29284736 (PubMedID)
    Note

    Funding Agencies|Swedish Heart-Lung Foundation; Torsten and Ragnar Soderbergs Foundation; Stroke Foundation; Olle Engkvist Foundation; Swedish Gamla Tjanarinnor Foundation; Linkoping University; Linkoping University Hospital Research Fund

    Available from: 2018-02-09 Created: 2018-02-09 Last updated: 2019-04-17
  • Pettersson, Albin
    Linköping University, Department of Computer and Information Science.
    Engelska som kommandospråk inom marina operationer i den svenska Försvarsmakten2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The report covers a study of the usage of English with NATO-standard within the Swedish Military’s Marine Force and Navy. Employees within different organizations have been interviewed regarding the parallell usage of the english language combined with their every-day working tasks and how the language is affecting their ability to keep on operating at a desirable level. All the interviewees have noticed a wide range of problems regarding how the language should be used according to their directives, that the problems are mainly concerning how the language is affecting their levels of stress when it creates communication problems, interpretation difficulties and makes ordinary tasks require more time to finish, even though their personal tasks might not always be affected directly. Carrier possibilities are also affected negatively, when language proficiency is prioritized over working experience and general competence, which over time could lead to a less experienced organization. A number of suggestions is given regarding how the language should be viewed upon in near the future.

  • Public defence: 2019-05-31 13:00 Hugo Theorell, Norra Entrén, Linköping
    Ziegler, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Improving Assessments of Hemodynamics and Vascular Disease2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Blood vessels are more than simple pipes, passively enabling blood to pass through them. Their form and function are dynamic, changing with both aging and disease. This process involves a feedback loop wherein changes to the shape of a blood vessel affect the hemodynamics, causing yet more structural adaptation. This feedback loop is driven in part by the hemodynamic forces generated by the blood flow, and the distribution and strength of these forces appear to play a role in the initiation, progression, severity, and the outcome of vascular diseases.

    Magnetic Resonance Imaging (MRI) offers a unique platform for investigating both the form and function of the vascular system. The form of the vascular system can be examined using MR-based angiography, to generate detailed geometric analyses, or through quantitative techniques for measuring the composition of the vessel wall and atherosclerotic plaques. To complement these analyses, 4D Flow MRI can be used to quantify the functional aspect of the vascular system, by generating a full time-resolved three-dimensional velocity field that represents the blood flow.

    This thesis aims to develop and evaluate new methods for assessing vascular disease using novel hemodynamic markers generated from 4D Flow MRI and quantitative MRI data towards the larger goal of a more comprehensive non-invasive examination oriented towards vascular disease. In Paper I, we developed and evaluated techniques to quantify flow stasis in abdominal aortic aneurysms to measure this under-explored aspect of aneurysmal hemodynamics. In Paper II, the distribution and intensity of turbulence in the aorta was quantified in both younger and older men to understand how aging changes this aspect of hemodynamics. A method to quantify the stresses generated by turbulence that act on the vessel wall was developed and evaluated using simulated flow data in Paper III, and in Paper V this method was utilized to examine the wall stresses of the carotid artery. The hemodynamics of vascular disease cannot be uncoupled from the anatomical changes the vessel wall undergoes, and therefore Paper IV developed and evaluated a semi-automatic method for quantifying several aspects of vessel wall composition. These developments, taken together, help generate more valuable information from imaging data, and can be pooled together with other methods to form a more comprehensive non-invasive examination for vascular disease.

    List of papers
    1. Visualizing and quantifying flow stasis in abdominal aortic aneurysms in men using 4D flow MRI
    Open this publication in new window or tab >>Visualizing and quantifying flow stasis in abdominal aortic aneurysms in men using 4D flow MRI
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    2019 (English)In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 57, p. 103-110Article in journal (Refereed) Published
    Abstract [en]

    Purpose: To examine methods for visualizing and quantifying flow stasis in abdominal aortic aneurysms (AAA) using 4D Flow MRI. Methods: Three methods were investigated: conventional volumetric residence time (VRT), mean velocity analysis (MVA), and particle travel distance analysis (TDA). First, ideal 4D Flow MRI data was generated using numerical simulations and used as a platform to explore the effects of noise and background phase-offset errors, both of which are common 4D Flow MRI artifacts. Error-free results were compared to noise or offset affected results using linear regression. Subsequently, 4D Flow MRI data for thirteen (13) subjects with AAA was acquired and used to compare the stasis quantification methods against conventional flow visualization. Results: VRT (R-2 = 0.69) was more sensitive to noise than MVA (R-2 = 0.98) and TDA (R-2 = 0.99) at typical noncontrast signal-to-noise ratio levels (SNR = 20). VRT (R-2 = 0.14) was more sensitive to background phase-offsets than MVA (R-2 = 0.99) and TDA (R-2 = 0.96) when considering a 95% effective background phase-offset correction. Qualitatively, TDA outperformed MVA (Wilcoxon p amp;lt; 0.005, mean score improvement 1.6/5), and had good agreement (median score 4/5) with flow visualizations. Conclusion: Flow stasis can be quantitatively assessed using 4D Flow MRI. While conventional residence time calculations fail due to error accumulation as a result of imperfect measured velocity fields, methods that do not require lengthy particle tracking perform better. MVA and TDA are less sensitive to measurement errors, and TDA generates results most similar to those obtained using conventional flow visualization.

    Place, publisher, year, edition, pages
    ELSEVIER SCIENCE INC, 2019
    Keywords
    Abdominal aortic aneurysm; Hemodynamics; 4D flow MRI; Flow stasis
    National Category
    Medical Laboratory and Measurements Technologies
    Identifiers
    urn:nbn:se:liu:diva-154524 (URN)10.1016/j.mri.2018.11.003 (DOI)000458096100012 ()30445146 (PubMedID)
    Available from: 2019-02-20 Created: 2019-02-20 Last updated: 2019-04-17
    2. Age-Related Vascular Changes Affect Turbulence in Aortic Blood Flow
    Open this publication in new window or tab >>Age-Related Vascular Changes Affect Turbulence in Aortic Blood Flow
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    2018 (English)In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, article id 36Article in journal (Refereed) Published
    Abstract [en]

    Turbulent blood flow is implicated in the pathogenesis of several aortic diseases but the extent and degree of turbulent blood flow in the normal aorta is unknown. We aimed to quantify the extent and degree of turbulece in the normal aorta and to assess whether age impacts the degree of turbulence. 22 young normal males (23.7 +/- 3.0 y.o.) and 20 old normal males (70.9 +/- 3.5 y.o.) were examined using four dimensional flow magnetic resonance imaging (4D Flow MRI) to quantify the turbulent kinetic energy (TKE), a measure of the intensity of turbulence, in the aorta. All healthy subjects developed turbulent flow in the aorta, with total TKE of 3-19 mJ. The overall degree of turbulence in the entire aorta was similar between the groups, although the old subjects had about 73% more total TKE in the ascending aorta compared to the young subjects (young = 3.7 +/- 1.8 mJ, old = 6.4 +/- 2.4 mJ, p amp;lt; 0.001). This increase in ascending aorta TKE in old subjects was associated with age-related dilation of the ascending aorta which increases the volume available for turbulence development. Conversely, age-related dilation of the descending and abdominal aorta decreased the average flow velocity and suppressed the development of turbulence. In conclusion, turbulent blood flow develops in the aorta of normal subjects and is impacted by age-related geometric changes. Non-invasive assessment enables the determination of normal levels of turbulent flow in the aorta which is a prerequisite for understanding the role of turbulence in the pathophysiology of cardiovascular disease.

    Place, publisher, year, edition, pages
    FRONTIERS MEDIA SA, 2018
    Keywords
    turbulent kinetic energy (TKE); turbulent blood flow; aortic blood flow; aortic dilation; normal values; 4D flow MRI; phase contrast MRI
    National Category
    Physiology
    Identifiers
    urn:nbn:se:liu:diva-145129 (URN)10.3389/fphys.2018.00036 (DOI)000423400000001 ()29422871 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [2013-6077, 2014-6191]; Swedish Heart and Lung foundation [20140398]; Kangwon National University [D1001179-01-01]; Basic Science Research Program through the National Research Foundation of Korea (NRF) - Ministry of Education [2016R1A6A3A03006337]

    Available from: 2018-02-19 Created: 2018-02-19 Last updated: 2019-04-17
    3. Assessment of Turbulent Flow Effects on the Vessel Wall Using Four-Dimensional Flow MRI
    Open this publication in new window or tab >>Assessment of Turbulent Flow Effects on the Vessel Wall Using Four-Dimensional Flow MRI
    2017 (English)In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 77, no 6, p. 2310-2319Article in journal (Refereed) Published
    Abstract [en]

    Purpose: To explore the use of MR-estimated turbulence quantities for the assessment of turbulent flow effects on the vessel wall. Methods: Numerical velocity data for two patient-derived models was obtained using computational fluid dynamics (CFD) for two physiological flow rates. The four-dimensional (4D) Flow MRI measurements were simulated at three different spatial resolutions and used to investigate the estimation of turbulent wall shear stress (tWSS) using the intravoxel standard deviation (IVSD) of velocity and turbulent kinetic energy (TKE) estimated near the vessel wall. Results: Accurate estimation of tWSS using the IVSD is limited by the spatial resolution achievable with 4D Flow MRI. TKE, estimated near the wall, has a strong linear relationship to the tWSS (mean R(2=)0.84). Near-wall TKE estimates from MR simulations have good agreement to CFD-derived ground truth (mean R-2=0.90). Maps of near-wall TKE have strong visual correspondence to tWSS. Conclusion: Near-wall estimation of TKE permits assessment of relative maps of tWSS, but direct estimation of tWSS is challenging due to limitations in spatial resolution. Assessment of tWSS and near-wall TKE may open new avenues for analysis of different pathologies. (C) 2016 International Society for Magnetic Resonance in Medicine

    Place, publisher, year, edition, pages
    WILEY, 2017
    Keywords
    phase contrast magnetic resonance imaging; wall shear stress; turbulence; turbulent kinetic energy; aorta
    National Category
    Medical Image Processing
    Identifiers
    urn:nbn:se:liu:diva-138232 (URN)10.1002/mrm.26308 (DOI)000401270900022 ()27350049 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council; National Supercomputer Centre [SNIC2014-11-22]

    Available from: 2017-06-14 Created: 2017-06-14 Last updated: 2019-04-17
  • Petersen, Nikiforos
    Linköping University, Department of Management and Engineering, Political Science.
    The Common European Asylum System: Challenges and Opportunities in Greece. A Case Study2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to investigate decision-making and policy implementation in the European Union, specifically regarding the Common European Asylum System (CEAS) and to compare how the political intention corresponds to the reality of its implementation, using the example of Greece. Europe’s ability to handle migration and refugee flows has been severely tested in recent years due to the large number of people fleeing wars in Central Asia and the Middle East.

    The CEAS constitutes a fairly modern endeavor compared to other regional programs concerned with refugee protection but it has not yet made a significant improvement in how refugees are treated. At the same time, Greece has been in an acute socio-economic crisis since at least 2010.

    European integration has traditionally been subject to theoretical analysis through Moravcsiik’s Liberal Intergovernmentalism and various forms of formalism. This thesis has tried to apply Historical Institutionalism to explain certain facets of the CEAS and the recent and on-going ‘refugee’ crisis. In combination with other theories, Institutionalism can contribute to an understanding of recent forces towards further integration and divergence in the European Union.

  • Almlöf, Hanna
    et al.
    Linköping University, Department of Management and Engineering, Commercial and Business Law. Linköping University, Faculty of Arts and Sciences. Internationella Handelshögskolan i Jönköping.
    Per-Olof, Bjuggren
    Ratio - Näringslivets forskningsinstitut, Stockholm.
    What Matters in Design of Corporate Law2017Other (Other academic)
    Abstract [en]

    For the corporate business model to be successful, it is important to align the interests of thosewho control and finance the firm. Corporate law has here an important task to fulfill. It offers alegal framework that can facilitate for parties to conclude mutually preferable agreements atlow transaction costs. The purpose of the paper is to show how to design corporate law to fulfillthis task. A two-dimension model that simultaneously considers both regulation intensity andthe level of default of the corporate law is presented. Earlier literature treats these dimensionsseparately. By adding a transaction cost perspective to our model, we assess different regulatorytechniques and examine how legislation can help corporations by offering a standard contractthat lowers transaction costs of contracting. This can be achieved through a legislation thatcovers most contingencies and take the heterogeneity of firms into consideration. Furthermore,default rules or standards of opt-out character should be combined with other regulatorytechniques with lower transaction costs such as opt-in alternatives and menus.

  • Public defence: 2019-05-09 09:15 Planck, Fysikhuset, Linköping
    Sundman, Ann-Sofie
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Dog behaviour: Intricate picture of genetics, epigenetics, and human-dog relations2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Dogs, Canis familiaris, share the lives of humans all over the world. That dogs, and the behavior of dogs, are of interest to many is therefore no surprise. In this thesis, the main aim has been to identify factors that affect dogs’ behaviours.

    The dog, Canis familiaris, is our first domesticated animal. Since domestication, various types of dogs have developed through adaptation to an environment shared with humans and through our selective breeding, resulting in a unique variation in morphology and behaviour. Although there is an individual variation in the behaviour of dogs, there is also a difference between breeds. Moreover, selection during the last decades has split some breeds into divergent types. Labrador and golden retrievers are divided into a common type, for show and companionship, and a field type, for hunting. By comparing the breed types, we can study the effects of recent selection. In Paper I, we investigate differences in general behavioural traits between Labrador and golden retriever and between common and field type within the two breeds by using results from the standardized behaviour test Dog Mentality Assessment. There were differences between breeds and types for all behavioural traits. However, there was also an interaction between breed and type. Thus, a common/field-type Labrador does not behave like a common/field-type golden retriever. Even though they have been selected for similar traits, the selection has affected the general behavioural traits differently in the two breeds.

    In paper II, we were interested in dogs’ human-directed social skills. Dogs have a high social competence when it comes to humans. Two experiments commonly used to study these skills are the problem-solving test, where dogs’ human-directed behaviours when faced with a problem are measured, and the pointing test, where dogs are tested on how well they understand human gestures. We compared the social skills of German shepherds and Labrador retrievers, and of common- and field-type Labradors. Labradors were more successful in the pointing test and German shepherds stayed closer to their owners during the problem solving. Among Labrador types, the field type had more human eye contact than the common type. Importantly, when comparing the two experiments, we found no positive correlations between the problem-solving test and the pointing test, suggesting that the two tests measure different aspects of human-directed social behaviour in dogs.

    A previous study has identified two suggestive genetic regions for human-directed social behaviours during the problem-solving test in beagles. In paper III, we show that these SNPs are also associated to social behaviours in Labrador and golden retrievers. Moreover, the Labrador breed types differed significantly in allele frequencies. This indicates that the two SNPs have been affected by recent selection and may have a part in the differences in sociability between common and field type.

    The behaviour of dogs cannot simply be explained by genetics, there is also an environmental component. In paper IV, we study which factors that affect long-term stress in dogs. Long-term cortisol can be measured by hair samples. We found a clear synchronization in hair cortisol concentrations between dogs and their owners. Neither dogs’ activity levels nor their behavioural traits affected the cortisol, however, the personality of the owners did. Therefore, we suggest that dogs mirror the stress level of their owners.

    The mediator between genes and the environment is epigenetics, and one epigenetic factor is DNA methylation. In paper V, we compared methylation patterns of wolves and dogs as well as dog breeds. Between both wolves and dogs and among dogs there were substantial differences in methylated DNA regions, suggesting that DNA methylation is likely to contribute to the vast variation among canines. We hypothesize that epigenetic factors have been important during domestication and in breed formation.

    In this thesis, I cover several aspects on how dogs’ behaviours can be affected, and paint an intricate picture on how genetics, epigenetics, and human-dog relations forms dog behaviour.

    List of papers
    1. Similar recent selection criteria associated with different behavioural effects in two dog breeds
    Open this publication in new window or tab >>Similar recent selection criteria associated with different behavioural effects in two dog breeds
    2016 (English)In: Genes, Brain and Behavior, ISSN 1601-1848, E-ISSN 1601-183X, Vol. 15, no 8, p. 750-756Article in journal (Refereed) Published
    Abstract [en]

    Selection during the last decades has split some established dog breeds into morphologically and behaviourally divergent types. These breed splits are interesting models for behaviour genetics since selection has often been for few and well-defined behavioural traits. The aim of this study was to explore behavioural differences between selection lines in golden and Labrador retriever, in both of which a split between a common type (pet and conformation) and a field type (hunting) has occurred. We hypothesized that the behavioural profiles of the types would be similar in both breeds. Pedigree data and results from a standardized behavioural test from 902 goldens (698 common and 204 field) and 1672 Labradors (1023 and 649) were analysed. Principal component analysis revealed six behavioural components: curiosity, play interest, chase proneness, social curiosity, social greeting and threat display. Breed and type affected all components, but interestingly there was an interaction between breed and type for most components. For example, in Labradors the common type had higher curiosity than the field type (F1,1668 = 18.359; P < 0.001), while the opposite was found in goldens (F1,897 = 65.201; P < 0.001). Heritability estimates showed considerable genetic contributions to the behavioural variations in both breeds, but different heritabilities between the types within breeds was also found, suggesting different selection pressures. In conclusion, in spite of similar genetic origin and similar recent selection criteria, types behave differently in the breeds. This suggests that the genetic architecture related to behaviour differs between the breeds.

    Place, publisher, year, edition, pages
    Wiley-Blackwell Publishing Inc., 2016
    Keywords
    Behavioural genetics, behavioural test, dog behaviour, dogs, golden retriever, heritability, Labrador retriever, selection
    National Category
    Evolutionary Biology Zoology Behavioral Sciences Biology Genetics
    Identifiers
    urn:nbn:se:liu:diva-132746 (URN)10.1111/gbb.12317 (DOI)000393079000007 ()27520587 (PubMedID)
    Note

    Funding agencies: research council, Formas; Advanced Research Grant from the European Research Council (ERC) [322206]

    Available from: 2016-11-22 Created: 2016-11-22 Last updated: 2019-04-17Bibliographically approved
    2. Understanding of human referential gestures is not correlated to human-directed social behaviour in Labrador retrievers and German shepherd dogs
    Open this publication in new window or tab >>Understanding of human referential gestures is not correlated to human-directed social behaviour in Labrador retrievers and German shepherd dogs
    Show others...
    2018 (English)In: Applied Animal Behaviour Science, ISSN 0168-1591, E-ISSN 1872-9045, Vol. 201, p. 46-53Article in journal (Refereed) Published
    Abstract [en]

    Dogs are known to excel in interspecific communication with humans and both communicate with humans and follow human communicative cues. Two tests commonly used to test these skills are, firstly, the problem-solving paradigm, and, secondly, following human referential signals, for example pointing. The aim of the present study was to investigate whether dogs that seek more human contact in an unsolvable problem-solving paradigm also better understand human communicative cues in a pointing test. We also assessed between- and within-breed variation in both tests. 167 dogs were tested and were of the breeds German shepherd dog and Labrador retriever. The Labradors were separated into the two selection lines: common type (bred for show and pet) and field type (bred for hunting). A principal component analysis of behaviours during the problem solving revealed four components: Passivity, Experimenter Contact, Owner Contact and Eye Contact. We analysed the effect of these components on success rate in the pointing test and we found no effect for three of them, while a negative correlation was found for Owner Contact (F(1,147) = 6.892; P = 0.010). This was only present in common-typed Labradors. We conclude that the ability to follow a pointing cue does not predict the propensity for human-directed social behaviour in a problem-solving situation and suggest that the two tests measure different aspects of human-directed social behaviour in dogs.

    Place, publisher, year, edition, pages
    Elsevier, 2018
    Keywords
    Human-dog communication, Human-directed social behaviour, Pointing test, Problem-solving test, German shepherd dogs. Labrador retrievers
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-145542 (URN)10.1016/j.applanim.2017.12.017 (DOI)000430774800007 ()2-s2.0-85039704233 (Scopus ID)
    Note

    Funding agencies: European Research Council (ERC) [322206]

    Available from: 2018-03-05 Created: 2018-03-05 Last updated: 2019-04-17Bibliographically approved
    3. Sociality genes are associated with human-directed social behaviour in golden and Labrador retriever dogs
    Open this publication in new window or tab >>Sociality genes are associated with human-directed social behaviour in golden and Labrador retriever dogs
    Show others...
    2018 (English)In: PeerJ, ISSN 2167-8359, E-ISSN 2167-8359, Vol. 6, article id e5889Article in journal (Refereed) Published
    Abstract [en]

    Background: Dogs have human-directed social skills that allow them to communicate and cooperate with humans. We have previously identified two loci on chromosome 26 associated with human contact-seeking behaviors during an unsolvable problem task in laboratory beagles (Persson et A, 2016). The aim of the present study was to verify the single nucleotide polymorphisms (SNPs) in additional dog breeds. We also studied how the allele frequencies have changed during domestication and recent selection. Methods: Dogs of two breeds, 61 golden retrievers and 100 Labrador retrievers, were phenotyped and genotyped, and 19 wolves were genotyped. The Labrador retrievers were divided into common and field type by pedigree data to make it possible to study the effects of recent selection. All dogs were tested in an unsolvable problem task where human-directed social behaviors were scored. DNA from dogs (buccal swabs) and wolves (blood or brain tissue) was analyzed for genotype on two of the previously identified SNP markers, BICF2G630798942 (SNP1) and BICF2S23712114 (SNP2), by pyrosequencing. Results: There was genetic variation for SNP1 in both dog breeds whereas the wolves were fixed for this polymorphism, and for SNP2 there was variation in both dogs and wolves. For both SNPs, Labrador retriever types differed significantly in allele frequencies. We found associations between SNPs and human-directed social behavior in both dog breeds. In golden retrievers, SNP I was associated with physical contact variables, for example, with the duration of physical contact with the owner (F-2,F-56 = 4.389, p = 0.017). SNP2 was associated with several behavioral variables in both breeds, among others owner gazing frequency in both golden retrievers (F-2,F-55 = 6.330, p = 0.003) and Labradors (F-1,F-93 = 5.209, p = 0.025). Discussion: Our results verify the association between the previously identified SNPs and human-directed social behavior scored in an unsolvable problem task. Differences in allele frequencies suggest that these loci have been affected by selection. The results indicate that these genomic regions are involved in human-directed social behavior in not only beagles but in other dog breeds as well. We hypothesize that they may have been important during dog domestication.

    Place, publisher, year, edition, pages
    PEERJ INC, 2018
    Keywords
    Genetics; Dog genetics; Dog behavior; Human-dog communication; Human-directed social behavior; Golden retrievers; Labrador retrievers; Wolf; Domestication; Behavior genetics
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:liu:diva-153536 (URN)10.7717/peerj.5889 (DOI)000452327000008 ()30416887 (PubMedID)
    Note

    Funding Agencies|European Research Council (ERC) [322206]

    Available from: 2018-12-20 Created: 2018-12-20 Last updated: 2019-04-17
  • Public defence: 2019-05-09 10:15 Nobel (BL32), B-huset, Linköping
    Ghosh, Arpan
    Linköping University, Department of Mathematics, Mathematics and Applied Mathematics. Linköping University, Faculty of Science & Engineering.
    Mathematical modelling of flow through thin curved pipes with application to hemodynamics2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The problem of mathematical modelling of incompressible flows with low velocities through narrow curvilinear pipes is addressed in this thesis. The main motivation for this modelling task is to eventually model the human circulatory system in a simple way that can facilitate the medical practitioners to efficiently diagnose any abnormality in the system. The thesis comprises of four articles.

    In the first article, a two-dimensional model describing the elastic behaviour of the wall of a thin, curved,  exible pipe is presented. The wall is assumed to have a laminate structure consisting of several anisotropic layers of varying thickness. The width of the channel is allowed to vary along the pipe. The two-dimensional model takes the interactions of the wall with any surrounding material and the  fluid  flow into account and is obtained through a dimension reduction procedure. Examples of canonical shapes of pipes and their walls are provided with explicit systems of differential equations at the end.

    In the second article, a one-dimensional model describing the blood flow through a moderately curved, elastic blood vessel is presented. The two-dimensional model presented in the first paper is used to model the vessel wall while linearized Navier-Stokes equations are used to model the  flow through the channel. Surrounding muscle tissues and presence of external forces other than gravity are taken into account. The model is again obtained via a dimension reduction procedure based on the assumption of thinness of the vessel relative to its length. Results of numerical simulations are presented to highlight the influence of different factors on the blood flow.

    The one-dimensional model described in the second paper is used to derive a simplified one-dimensional model of a false aneurysm which forms the subject of the third article. A false aneurysm is an accumulation of blood outside a blood vessel but confined by the surrounding muscle tissue. Numerical simulations are presented which demonstrate different characteristics associated with a false aneurysm.

    In the final article, a modified Reynolds equation, along with its derivation from Stokes equations through asymptotic methods, is presented. The equation governs the steady flow of a fluid with low Reynolds number through a narrow, curvilinear tube. The channel considered may have large curvature and torsion. Approximations of the velocity and the pressure of the fluid inside the channel are constructed. These approximations satisfy a modified Poiseuille equation. A justification for the approximations is provided along with a comparison with a simpler case.

    List of papers
    1. A TWO-DIMENSIONAL MODEL OF THE THIN LAMINAR WALL OF A CURVILINEAR FLEXIBLE PIPE
    Open this publication in new window or tab >>A TWO-DIMENSIONAL MODEL OF THE THIN LAMINAR WALL OF A CURVILINEAR FLEXIBLE PIPE
    2018 (English)In: Quarterly Journal of Mechanics and Applied Mathematics, ISSN 0033-5614, E-ISSN 1464-3855, Vol. 71, no 3, p. 349-367Article in journal (Refereed) Published
    Abstract [en]

    We present a two-dimensional model describing the elastic behaviour of the wall of a curved flexible pipe. The wall has a laminate structure consisting of several anisotropic layers of varying thickness and is assumed to be much smaller in thickness than the radius of the channel which itself is allowed to vary. Our two-dimensional model takes the interaction of the wall with any surrounding or supporting material and the fluid flow into account and is obtained via a dimension reduction procedure. The curvature and twist of the pipes axis as well as the anisotropy of the laminate wall present the main challenges in applying the dimension reduction procedure so plenty of examples of canonical shapes of pipes and their walls are supplied with explicit systems of differential equations at the end.

    Place, publisher, year, edition, pages
    OXFORD UNIV PRESS, 2018
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-150869 (URN)10.1093/qjmam/hby009 (DOI)000441808700006 ()
    Note

    Funding Agencies|Russian Foundation of Basic Research [18-01-00325]

    Available from: 2018-09-06 Created: 2018-09-06 Last updated: 2019-04-16
    2. A one dimensional model of blood flow through a curvilinear artery
    Open this publication in new window or tab >>A one dimensional model of blood flow through a curvilinear artery
    2018 (English)In: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 63, p. 633-643Article in journal (Refereed) Published
    Abstract [en]

    We present a one-dimensional model describing the blood flow through a moderately curved and elastic blood vessel. We use an existing two dimensional model of the vessel wall along with Navier-Stokes equations to model the flow through the channel while taking factors, namely, surrounding muscle tissue and presence of external forces other than gravity into account. Our model is obtained via a dimension reduction procedure based on the assumption of thinness of the vessel relative to its length. Results of numerical simulations are presented to highlight the influence of different factors on the blood flow. (C) 2018 Elsevier Inc. All rights reserved.

    Place, publisher, year, edition, pages
    ELSEVIER SCIENCE INC, 2018
    Keywords
    Blood flow; Curvilinear vessel; Asymptotic analysis; Dimension reduction; Numerical simulation
    National Category
    Fluid Mechanics and Acoustics
    Identifiers
    urn:nbn:se:liu:diva-151627 (URN)10.1016/j.apm.2018.07.019 (DOI)000444362800034 ()
    Note

    Funding Agencies|Russian Foundation of Basic Research [18-01-00325]

    Available from: 2018-10-09 Created: 2018-10-09 Last updated: 2019-04-16
  • Mårtensson, Åsa
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education and Adult Learning. Linköping University, Faculty of Educational Sciences.
    Andersson, Per
    Linköping University, Department of Behavioural Sciences and Learning, Education and Adult Learning. Linköping University, Faculty of Educational Sciences.
    Nyström, Sofia
    Linköping University, Department of Behavioural Sciences and Learning, Education and Adult Learning. Linköping University, Faculty of Educational Sciences.
    A recruiter, a matchmaker, a firefighter: Swedish vocational teachers’ relational work2019In: Nordic Journal of Vocational Education and Training, E-ISSN 2242-458X, Vol. 9, no 1, p. 89-110Article in journal (Refereed)
    Abstract [en]

    A central part of Swedish vocational teachers’ work concerns their students’ work-based learning (WBL). The focus of this article is the character of the relational work carried out by teachers of vocational education and training (VET) concerning WBL. The qualitative study is based on 15 interviews with teachers on the upper-secondary level Child and Recreation, Building and Construction, and Handicraft programmes. The study is based on a situated learning perspective, and uses the concepts of community of practice, broker and boundary crossing. The findings highlight three central aspects of VET teachers’ relational work with WBL: recruiting workplaces for WBL, matchmaking between students and workplaces, and ‘firefighting’ to prevent and deal with problems that occur during WBL periods. The study contributes to the understanding of the work of VET teachers, as they cross the blurred boundaries between school and working life and strive to create a good learning environment for all students during WBL periods.

  • Fredman, Josefin
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Flinge, Lilian
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Utomhusmatematik- är det inne?: – En litteraturstudie om hur lärare och elever upplever utomhusmatematik och dess inverkan på elevers motivation.2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Utomhuspedagogik har haft störst genomslagskraft i matematiken. Denna litteraturstudie syftar till att undersöka hur lärare och elever i förskoleklass och årskurs 1-3 upplever utomhusmatematik och vilken inverkan utomhusmatematik kan ha på elevers motivation. Detta har undersökts genom att samla in, analysera och granska vad tidigare forskning visar. Studierna som utgör resultatet har hämtats via UniSearch och ERIC samt genom manuell sökning. Resultatet av litteraturstudien visar på en positiv inställning hos både lärare och elever vad det gäller utomhusmatematik. Vidare visar studien att elevers motivation ökar tack vare denna undervisningsmetod.

  • Wernberg, Max
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Security and Privacy of Controller Pilot Data Link Communication2018Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Newly implemented technologies within the aviation lack, according to recent studies, built in security measures to protect them against outside interference. In this thesis we study the security and privacy status of the digital wireless Controller Pilot Data Link Communication (CPDLC) used in air traffic management alongside other systems to increase the safety and traffic capacity of controlled airspaces. The findings show that CPDCL is currently insecure and exposed to attacks. Any solutions to remedy this must adhere to its low levels of performance. Elliptical Curve Cryptography, Protected ACARS and Host Identity Protocol have been identified as valid solutions to the system’s security drawbacks and all three are possible to implement in the present state of CPDLC.

  • Grabmüller, Sandra
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Lagerstyrning för datorer ute ifält2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Detta examensarbete har genomförts på MSB och handlar om att ta fram ett förslag på lagerstyningen för datorer ute i fält till MSB.

  • Sandqvist Wedin, Emma
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology.
    Optimization of Acidic Degradation of Hyaluronic Acid using Design of Experiments2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Hyaluronic acid (HA) is an unbranched polysaccharide consisting of the repeating disaccharide unit β(1→4)-GlcA-β(1→3)-GlcNAc and is a naturally occurring biopolymer in bacteria and vertebras. HA is predominantly found in the extracellular matrix (ECM) and the in vivo function of HA can vary depending on molecular weight (Mw) for instance high Mw HA is reported to be anti-angiogenic while low Mw HA induces angiogenesis. HA is a popular component for hydrogels such as dermal fillers. HA is commonly used in dermal fillers. However, other materials, such as other polymers, can be used as well. The project goal was to investigate different degradation processes for production of target Mw HA. Alkaline and acidic degradation processes in combination with increased temperatures seemed as the most promising methods. Degradation tests performed both in aqueous solution as well as heterogeneously in ethanol were evaluated. The acidic degradation in aqueous solution was proven to have the largest degradation constant. Both a robustness test as well as a Design of Experiments (DoE) was performed to investigate the influence different factors had on the degradation speed. The investigated factors were HA concentration, HCl concentration and temperature. Temperature and HCl concentrations proved to be the most influencing factors and a model was developed in the DoE software MODDE to describe how the factors influenced the degradation constant. The model was established as a good significant model with a Q2 value of 0.998 and relative standard deviation (RSD) value of 0.022 after a logarithmic transformation was performed as well as a simplification of the model by excluding some of the factor interactions. The acidic degradation method also proved to be a highly robust method which easily could be used to produce target Mw HA.

  • Mollet, Jelke
    et al.
    Linköping University, Department of Social and Welfare Studies.
    Wahlinder Stål, Tina
    Linköping University, Department of Social and Welfare Studies.
    Undervisning i förskolan: Ett definitionsträsk2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studie är att undersöka hur pedagoger i förskolan, det vill säga barnskötare och förskollärare, resonerar kring begreppet undervisning. Studien ämnar svara på frågorna hur pedagoger reflekterar kring undervisningsbegreppet samt hur undervisning kan ske i förskolan enligt pedagogerna. Studien utgår från ett social konstruktionistiskt perspektiv och vi har samlat in material genom kvalitativa intervjuer med tio förskolepedagoger som sedan analyserats genom en kvalitativ tematisk analys med hjälp av framework.

    Resultatet av studien visar att pedagogerna är villiga att ta upp det nya begreppet med undervisning i förskolan och diskuterar vad det innebär i en förskolekontext. Våra informanter uppvisar ingen skolifieringsskräck som tidigare forskning visat på. Studien visar även på att det råder en viss begreppsförvirring mellan undervisning och lärande. Begreppen anses ibland synonyma och ibland ges begreppen olika definitioner. Vi kan genom studien dra slutsatser om vikten av begreppsdefinitioner så att begrepp inte urholkas. Genom pedagogernas resonemang framkommer att de ser sin utbildning och vidare kompetensutveckling som en viktig aspekt för att kunna bedriva undervisning i förskolan.

    Framtida forskning kan fokusera på en begreppsdefinition av lärande och undervisning och hur begreppen kan särskiljas. Det är även möjligt att studera vad som kännetecknar spontan undervisning i förskolan och när den kan ske. Pedagoger har ett behov av att kunna identifiera när undervisning sker så att inte allt blir undervisning och begreppet därmed urholkas.

  • Eilert, Pernilla
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems.
    Learning behaviour trees for simulated fighter pilots in airborne reconnaissance missions: A grammatical evolution approach2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Fighter pilots often find themselves in situations where they need to make quick decisions. Therefore an intelligent decision support system that suggests how the fighter pilot should act in a specific situation is vital. The aim of this project is to investigate and evaluate grammatical evolution paired with behaviour trees to develop a decision support system. This support system should control a simulated fighter pilot during an airborne reconnaissance mission. This thesis evaluates the complexity of the evolved trees and the performance, and robustness of the algorithm. Key factors were identified for a successful system: scenario, fitness function, initialisation technique and control parameters. The used techniques were decided based on increasing performance of the algorithm and decreasing complexity of the tree structures. The initialisation technique, the genetic operators and the selection functions performed well but the fitness function needed more work. Most of the experiments resulted in local maxima. A desired solution could only be found if the initial population contained an individual with a BT succeeding the mission. However, the implementation behaved as expected. More and longer simulations are needed to draw a conclusion of the performance based on robustness, when testing the evolved BT:s on different scenarios. Several methods were studied to decrease the complexity of the trees and the experiments showed a promising variation of complexity through the generations when the best fitness was fixed. A feature was added to the algorithm, to promote lower complexity when equal fitness value. The results were poor and implied that pruning would be a better fit after the simulations. Nevertheless, this thesis suggests that it is suitable to implement a decision support system based on grammatical evolution paired with behaviour trees as framework.

  • Halilic, Senija
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences.
    Kämmerling, Nina
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences.
    Värdet av DT-buköversikt som primär undersökning vid akut buksmärta2016Report (Other academic)
    Abstract [sv]

    Syftet med studien var att se hur stor andel av de patienter som genomgått DT-BÖS vid akut påkomna buksymptom som behöver genomgå kompletterande undersökning, samt vilken diagnos som ställdes vid den kompletterande undersökningen. Vilka frågeställningar besvarar DT-BÖS vid akut påkommen buksmärta? Vilka frågeställningar motiverar annan  undersökning som förstahandsundersökning?

  • Public defence: 2019-05-10 10:15 ACAS, Linköping
    Lawrence, Akvile
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Energy Management for Improving Energy Efficiency in the Pulp and Paper Industry: Success Factors for Strengthening Drivers and Overcoming Barriers2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Industrial energy efficiency improves the profit and competitive advantage of companies. The pulp and paper industry (PPI) being one of the five most energy-intensive industries uses 5.6% of global industrial energy, according to the International Energy Agency. It is one of the key sectors that is faced with the challenge of improving energy efficiency. The PPI is not less important in Sweden where it uses ~52% of the total industrial energy, employing >20000 people and where improvement of the energy end-use by 1% corresponds to estimated savings of ~218 MSEK annually. Energy management (EnM) is a means for improving energy efficiency (EE). However, despite research showing the possibility for annual improvement of the energy end-use by e.g. 5.5-19.4%, EnM is not always used to its full potential or often hardly implemented, resulting in an EE gap, i.e. the difference between the optimal and actual energy efficiency. Why then does this EE gap exist? What are the drivers and barriers for practicing EnM to its full potential and thus improving energy efficiency? What are the success factors for encouraging the drivers and overcoming the barriers? What practical recommendations can be made that could lead to the improvement of energy efficiency? After extracting information from historical and current information using tools from multivariate data analysis (MDA), this PhD dissertation presents new knowledge that intends to contribute to overcome the challenges of improving energy efficiency in the PPI. Specifically, international research primarily addressing EnM in the PPI showed that EnM in the PPI is perceived as EnM via technology, despite that EnM contains other aspects than EnM via technology, e.g. proactive EnM practices. This result indicates the presence of a knowledgegap on how to deploy EnM in the PPI. Studies of the PPI in Sweden showed different EnM practices among the individual types of mills, i.e. pulp mills, paper mills and integrated-pulp and paper mills. Integrated mills seemed to measure the energy-related performance more than pulp mills and paper mills. However, the results also suggested that the Swedish PPI worked continuously and regularly with EnM. Further, aside from the top ranked perceived drivers being economical and the barriers being organizational, knowledge related drivers and barriers were amongst the most important. High ranking of the knowledge related drivers and barriers together with the results that commonly only selected employees were trained in EnM indicated that communication between the trained employees and operations personnel and the absorptive capacity for energy issues could potentially be improved. Additionally, research showed that by using MDA, previously unstudied/unidentified connections were discovered such as that during the ten-year voluntary agreement policy program known as PFE (Program for improved energy efficiency in energy-intensive industry), companies less financially stable and less experienced with EnM tended to save electricity more than the more financially stable and more EnM experienced mills. Furthermore, results also demonstrate that the specific energy use, also known as specific energy consumption (SEC), that is commonly used as the energy key performance indicator for energy efficiency needs to be used with more clarity and caution for assuring validity of the benchmarking of energy efficiency. Altogether, the success factors for EnM for improving energy efficiency could be summarized in the versatile 4M memory tool - The “4M for energy efficiency”: mind, measure, monitor and manage. The “4M for energy efficiency” suggests that all the four “Ms” should be practiced simultaneously in order to maximize the achievement of goals of EnM in the PPI and as well as in other sectors.

    List of papers
    1. Drivers, Barriers, and Success Factors for Improving Energy Management in the Pulp and Paper Industry
    Open this publication in new window or tab >>Drivers, Barriers, and Success Factors for Improving Energy Management in the Pulp and Paper Industry
    2018 (English)In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 6, article id 1851Article, review/survey (Refereed) Published
    Abstract [en]

    Successful energy management is a way to achieve energy efficiency in the pulp and paper industry (PPI), which is important for assuring energy supply security, for increasing economic competitiveness, and for mitigating greenhouse gases. However, research shows that although energy use within PPI can be reduced by 5.5-19.4% per year, some of this by energy management practices, energy management is not always implemented. Why is this so? What are the barriers to, and drivers of implementation? How can the barriers be overcome? A systematic review of barriers and drivers in energy management in the PPI within peer-reviewed scientific articles suggests that the world-wide events that affect energy supply, volatility, and use seemingly also affect the number and frequency of research articles on energy management in the PPI. The perception of energy management in the PPI seems to be dominated by the understanding that it can mostly be achieved through technological improvements aiming to improve energy efficiency. The main driver of energy management was shown to be economic conditions: high and unstable energy prices, followed by drivers such as the need to remain internationally competitive, collaboration and energy management systems. Meanwhile, examples of the most important barriers are technical risks, lack of access to capital, lack of time and other priorities, and slim organization. The success factors for enhancing drivers and overcoming barriers were continuous energy accounting, energy-related collaboration, energy-efficiency programmes, and benchmarking. Altogether, success factors for energy management for improved energy efficiency could be summarized in the 4M frameworkthe 4M for energy efficiency: mind, measure, monitor, and managethat could be used as the energy management memory-tool that could lead to improved energy efficiency in other sectors as well.

    Place, publisher, year, edition, pages
    MDPI, 2018
    Keywords
    energy management; energy efficiency; pulp and paper industry; barriers; drivers; ISO 50001; success factors
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-151523 (URN)10.3390/su10061851 (DOI)000436570100163 ()
    Note

    Funding Agencies|Swedish Energy Agency [2015-002143]; Division of Energy Systems in the Department of Management and Engineering at Linkoping University

    Available from: 2018-09-24 Created: 2018-09-24 Last updated: 2019-04-12
    2. Effects of firm characteristics and energy management for improving energy efficiency in the pulp and paper industry
    Open this publication in new window or tab >>Effects of firm characteristics and energy management for improving energy efficiency in the pulp and paper industry
    2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 153, p. 825-835Article in journal (Refereed) Published
    Abstract [en]

    The Swedish pulp and paper industry (PPI) must increase energy efficiency to remain competitive on the global market, which has experienced entries from countries with cheaper energy and raw material supplies. Interactions among variables for energy use, production, energy management, electricity price and firm characteristics (FC), in different types of mills, i.e., pulp, paper and integrated mills, in Sweden from 2006 to 2015 indicate that correlations among the studied variables were different in different types of mills. This difference between types of mills seemed to originate partly from varying accessibility to production residue that could be used for energy. For all types of mills, variation of electricity prices did not correlate significantly with energy efficiency during the study period. The studied FC were firms age, number of employees, number of companies in company group, net sales and profit for the year. Energy efficiency was more affected by the variables characterizing energy and production compared to the variables representing FC. This study also suggested presence of possible discrepancies between FC that were perceived as barriers to energy management towards energy efficiency, according to previous studies, and what was shown by the data combining variables representing energy use, production and FC. (C) 2018 Elsevier Ltd. All rights reserved.

    Place, publisher, year, edition, pages
    PERGAMON-ELSEVIER SCIENCE LTD, 2018
    Keywords
    Energy efficiency; Specific energy; Pulp and paper industry; Firm characteristics; Energy intensive industry; Energy management
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-150880 (URN)10.1016/j.energy.2018.04.092 (DOI)000436651100074 ()
    Note

    Funding Agencies|Swedish Energy Agency

    Available from: 2018-09-06 Created: 2018-09-06 Last updated: 2019-04-12
    3. Drivers, barriers and success factors for energy management in the Swedish pulp and paper industry
    Open this publication in new window or tab >>Drivers, barriers and success factors for energy management in the Swedish pulp and paper industry
    Show others...
    2019 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 223, p. 67-82Article in journal (Refereed) Published
    Abstract [en]

    Research has revealed the existence of an energy-efficiency gap – the difference between optimal and actual energy end-use, suggesting that energy efficiency can be improved. Energy management (EnM) is a means for improving industrial energy efficiency. However, due to various barriers, the full potential of EnM is not realised. Several studies have addressed drivers and barriers to energy efficiency but few to EnM. This study aims to identify EnM practices, the most important perceived drivers and barriers for EnM, and relations among them in the energy-intensive Swedish pulp and paper industry (PPI), which has the longest experience internationally of practising EnM systems, and has worked according to the standards since 2004. Our results show that, altogether, the PPI works regularly and continuously with EnM, with a clear division of responsibilities. The highest maturity for EnM practices was for energy policy, followed by organization, investments, and performance measurement. The study also shows that communication between middle management and operations personnel has potential for improvement. The most important categories of drivers were economic, whereas for barriers they were organizational. Nevertheless, knowledge-related barriers and drivers were amongst the most important, suggesting that the absorptive capacity for energy issues could be improved.

    Keywords
    Barriers, Drivers, Success factors, Energy management, Energy efficiency, Pulp and paper industry
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-156271 (URN)10.1016/j.jclepro.2019.03.143 (DOI)
    Available from: 2019-04-10 Created: 2019-04-10 Last updated: 2019-04-12
    4. Effects of monetary investment, payback time and firm characteristics on electricity saving in energy-intensive industry
    Open this publication in new window or tab >>Effects of monetary investment, payback time and firm characteristics on electricity saving in energy-intensive industry
    2019 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 240, p. 499-512Article in journal (Refereed) Published
    Abstract [en]

    Our study looked at the extent to which firm characteristics such as total firm capital affect electricity saving in energy-intensive industry in Sweden from 2007 to 2015. Specifically, the most influential variables for systematic variation in electricity saving in the energy-intensive companies participating in Sweden’s voluntary programme for improving energy efficiency in energy-intensive industry (the PFE) were studied by analysing monetary investment, payback time and firm characteristics. Monetary investment and payback time influenced electricity savings during the PFE more than firm characteristics, with monetary investment being most influential. Nevertheless, the total systematic variation in firm characteristics may account for ∼16% of the systematic variation in electricity saving, where ∼74% (32 of 43) of the studied firm characteristics seemed to merit further investigation and where ∼49% (21 of 43) of firm characteristics appeared most influential. The most influential firm characteristics were total firm capital, stock turnover ratio, machinery, short-term liabilities per turnover ratio and goodwill. The overall results showed that firm characteristics can influence a firm’s energy-saving activities and indicated a tendency for more energy savings in companies that were financially weaker or had done less work to improve energy efficiency prior to the PFE.

    Keywords
    Energy efficiency, Energy saving, Energy intensive industry, Energy management, Firm characteristics, Voluntary agreement
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-156280 (URN)10.1016/j.apenergy.2019.02.060 (DOI)
    Available from: 2019-04-11 Created: 2019-04-11 Last updated: 2019-04-12
    5. Specific Energy Consumption/Use (SEC) in Energy Management for Improving Energy Efficiency in Industry: Meaning, Usage and Differences
    Open this publication in new window or tab >>Specific Energy Consumption/Use (SEC) in Energy Management for Improving Energy Efficiency in Industry: Meaning, Usage and Differences
    2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 2, article id 247Article in journal (Refereed) Published
    Abstract [en]

    Although several research studies have adopted specific energy consumption (SEC) as an indicator of the progress of improved energy efficiency, publications are scarce on critical assessments when using SEC. Given the increasing importance of monitoring improved industrial energy efficiency and the rising popularity of SEC as an energy key performance indicator (e-KPI), an in-depth analysis and problematization on the pros and cons of using SEC would appear to be needed. The aim of this article is to analyse SEC critically in relation to industrial energy efficiency. By using SEC in the pulp and paper industry as an example, the results of this exploratory study show that although SEC is often used as an e-KPI in industry, the comparison is not always straightforward. Challenges emanate from a lack of information about how SEC is calculated. It is likely that SEC is an optimal e-KPI within the same study, when all deployed SECs are calculated in the same way, and with the same underlying assumptions. However, before comparing SEC with other studies, it is recommended that the assumptions on which calculations are based should be scrutinized in order to ensure the validity of the comparisons. The paper remains an important contribution in addition to the available handbooks.

    Place, publisher, year, edition, pages
    MDPI, 2019
    Keywords
    specific energy consumption; specific energy use; specific energy; SEC; energy management; energy efficiency; industry; energy use; manufacturing
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-155606 (URN)10.3390/en12020247 (DOI)000459743700048 ()
    Note

    Funding Agencies|Swedish Energy Agency [40537-1]; Swedish Environmental Protection Agency [802-0082-17]; Division of Energy Systems at the Department of Management and Engineering, Linkoping University

    Available from: 2019-03-21 Created: 2019-03-21 Last updated: 2019-04-12
  • Gagiu, Răzvan-Florin-Rainer
    et al.
    Linköping University, Department of Management and Engineering, Machine Design.
    Abin, Kakkattil Paulose
    Linköping University, Department of Management and Engineering, Machine Design.
    Modeling and Simulation of novel Environmental Control System for a combat aircraft2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The present thesis deals with the analysis of Environmental Control System (ECS) as a part of the aircraft conceptual design. The research focuses on developing methods for modelling, simulation and optimization of current and future cooling technologies suitable for aircraft applications. The work started with a pre-study in order to establish the suitability of different cooling technologies for ECS application. Therefore, five technologies namely, Bootstrap (BS), Reverse-Bootstrap (RBS), vapour cycle system (VCS), magnetic cooling (MC) and thermo-electric cooling (EC), were assessed from a theoretical point of view by the method of benchmarking. This resulted into the selection of three most suitable technologies that were further modelled and simulated in Dymola. In order to compare the optimum designs for each technology, the models were optimized using the modeFRONTIER software. The comparison was performed based on the optimum ratio of maximum power of cooling and minimum fuel penalty. The results showed that VCS has the “best” performances compared to BS and RBS. In addition to the active technologies, passive cooling methods such as liquid cooling by means of jet-fuel and poly-alpha-olefin were considered to address high heat transfer rates. In order to apply the cooling technologies in the ECS, concept system architectures were formulated using the functional analysis. This led to the identification of basic functions, components and sub-systems interaction. Based on the comparison carried out previously and the functional analysis, two ECS architectures were developed. Design optimization procedure was applied further in order to assess each concept and also to study the differences between the two concept architectures. The results depict the complex interaction of different key parameters of the architectures and their influence on the outcome. The study culminated with a proposed methodology for formulation of systems architecture using information from the optimization results and a robust functional analysis method. To sum up, the thesis proposes a simulation-based optimization method that allows inclusion of ECS system in aircraft conceptual design phase. The study also proves the complexity of the conceptual design stage for ECS architectures which highly influences the design of the combat aircraft.

  • Public defence: 2019-04-26 13:15 Domen, Visualiseringscenter C, Norrköping
    Grelsson, Bertil
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, Faculty of Science & Engineering.
    Vision-based Localization and Attitude Estimation Methods in Natural Environments2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Over the last decade, the usage of unmanned systems such as Unmanned Aerial Vehicles (UAVs), Unmanned Surface Vessels (USVs) and Unmanned Ground Vehicles (UGVs) has increased drastically, and there is still a rapid growth. Today, unmanned systems are being deployed in many daily operations, e.g. for deliveries in remote areas, to increase efficiency of agriculture, and for environmental monitoring at sea. For safety reasons, unmanned systems are often the preferred choice for surveillance missions in hazardous environments, e.g. for detection of nuclear radiation, and in disaster areas after earthquakes, hurricanes, or during forest fires. For safe navigation of the unmanned systems during their missions, continuous and accurate global localization and attitude estimation is mandatory.

    Over the years, many vision-based methods for position estimation have been developed, primarily for urban areas. In contrast, this thesis is mainly focused on vision-based methods for accurate position and attitude estimates in natural environments, i.e. beyond the urban areas. Vision-based methods possess several characteristics that make them appealing as global position and attitude sensors. First, vision sensors can be realized and tailored for most unmanned vehicle applications. Second, geo-referenced terrain models can be generated worldwide from satellite imagery and can be stored onboard the vehicles. In natural environments, where the availability of geo-referenced images in general is low, registration of image information with terrain models is the natural choice for position and attitude estimation. This is the problem area that I addressed in the contributions of this thesis.

    The first contribution is a method for full 6DoF (degrees of freedom) pose estimation from aerial images. A dense local height map is computed using structure from motion. The global pose is inferred from the 3D similarity transform between the local height map and a digital elevation model. Aligning height information is assumed to be more robust to season variations than feature-based matching.

    The second contribution is a method for accurate attitude (pitch and roll angle) estimation via horizon detection. It is one of only a few methods that use an omnidirectional (fisheye) camera for horizon detection in aerial images. The method is based on edge detection and a probabilistic Hough voting scheme. The method allows prior knowledge of the attitude angles to be exploited to make the initial attitude estimates more robust. The estimates are then refined through registration with the geometrically expected horizon line from a digital elevation model. To the best of our knowledge, it is the first method where the ray refraction in the atmosphere is taken into account, which enables the highly accurate attitude estimates.

    The third contribution is a method for position estimation based on horizon detection in an omnidirectional panoramic image around a surface vessel. Two convolutional neural networks (CNNs) are designed and trained to estimate the camera orientation and to segment the horizon line in the image. The MOSSE correlation filter, normally used in visual object tracking, is adapted to horizon line registration with geometric data from a digital elevation model. Comprehensive field trials conducted in the archipelago demonstrate the GPS-level accuracy of the method, and that the method can be trained on images from one region and then applied to images from a previously unvisited test area.

    The CNNs in the third contribution apply the typical scheme of convolutions, activations, and pooling. The fourth contribution focuses on the activations and suggests a new formulation to tune and optimize a piecewise linear activation function during training of CNNs. Improved classification results from experiments when tuning the activation function led to the introduction of a new activation function, the Shifted Exponential Linear Unit (ShELU).

    List of papers
    1. Efficient 7D Aerial Pose Estimation
    Open this publication in new window or tab >>Efficient 7D Aerial Pose Estimation
    2013 (English)In: 2013 IEEE Workshop on Robot Vision (WORV), IEEE , 2013, p. 88-95Conference paper, Published paper (Refereed)
    Abstract [en]

    A method for online global pose estimation of aerial images by alignment with a georeferenced 3D model is presented.Motion stereo is used to reconstruct a dense local height patch from an image pair. The global pose is inferred from the 3D transform between the local height patch and the model.For efficiency, the sought 3D similarity transform is found by least-squares minimizations of three 2D subproblems.The method does not require any landmarks or reference points in the 3D model, but an approximate initialization of the global pose, in our case provided by onboard navigation sensors, is assumed.Real aerial images from helicopter and aircraft flights are used to evaluate the method. The results show that the accuracy of the position and orientation estimates is significantly improved compared to the initialization and our method is more robust than competing methods on similar datasets.The proposed matching error computed between the transformed patch and the map clearly indicates whether a reliable pose estimate has been obtained.

    Place, publisher, year, edition, pages
    IEEE, 2013
    Keywords
    Pose estimation, aerial images, registration, 3D model
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-89477 (URN)10.1109/WORV.2013.6521919 (DOI)000325279400014 ()978-1-4673-5646-6 (ISBN)978-1-4673-5647-3 (ISBN)
    Conference
    IEEE Workshop on Robot Vision 2013, Clearwater Beach, Florida, USA, January 16-17, 2013
    Available from: 2013-02-26 Created: 2013-02-26 Last updated: 2019-04-12
    2. Probabilistic Hough Voting for Attitude Estimation from Aerial Fisheye Images
    Open this publication in new window or tab >>Probabilistic Hough Voting for Attitude Estimation from Aerial Fisheye Images
    2013 (English)In: Image Analysis: 18th Scandinavian Conference, SCIA 2013, Espoo, Finland, June 17-20, 2013. Proceedings / [ed] Joni-Kristian Kämäräinen and Markus Koskela, Springer Berlin/Heidelberg, 2013, p. 478-488Conference paper, Published paper (Refereed)
    Abstract [en]

    For navigation of unmanned aerial vehicles (UAVs), attitude estimation is essential. We present a method for attitude estimation (pitch and roll angle) from aerial fisheye images through horizon detection. The method is based on edge detection and a probabilistic Hough voting scheme.  In a flight scenario, there is often some prior knowledge of the vehicle altitude and attitude. We exploit this prior to make the attitude estimation more robust by letting the edge pixel votes be weighted based on the probability distributions for the altitude and pitch and roll angles. The method does not require any sky/ground segmentation as most horizon detection methods do. Our method has been evaluated on aerial fisheye images from the internet. The horizon is robustly detected in all tested images. The deviation in the attitude estimate between our automated horizon detection and a manual detection is less than 1 degree.

    Place, publisher, year, edition, pages
    Springer Berlin/Heidelberg, 2013
    Series
    Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349 ; 7944
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-98066 (URN)10.1007/978-3-642-38886-6_45 (DOI)000342988500045 ()978-3-642-38885-9 (ISBN)978-3-642-38886-6 (ISBN)
    Conference
    18th Scandinavian Conferences on Image Analysis (SCIA 2013), 17-20 June 2013, Espoo, Finland.
    Projects
    CIMSMAP
    Available from: 2013-09-27 Created: 2013-09-27 Last updated: 2019-04-12Bibliographically approved
    3. Highly Accurate Attitude Estimation via Horizon Detection
    Open this publication in new window or tab >>Highly Accurate Attitude Estimation via Horizon Detection
    2016 (English)In: Journal of Field Robotics, ISSN 1556-4959, E-ISSN 1556-4967, Vol. 33, no 7, p. 967-993Article in journal (Refereed) Published
    Abstract [en]

    Attitude (pitch and roll angle) estimation from visual information is necessary for GPS-free navigation of airborne vehicles. We propose a highly accurate method to estimate the attitude by horizon detection in fisheye images. A Canny edge detector and a probabilistic Hough voting scheme are used to compute an approximate attitude and the corresponding horizon line in the image. Horizon edge pixels are extracted in a band close to the approximate horizon line. The attitude estimates are refined through registration of the extracted edge pixels with the geometrical horizon from a digital elevation map (DEM), in our case the SRTM3 database, extracted at a given approximate position. The proposed method has been evaluated using 1629 images from a flight trial with flight altitudes up to 600 m in an area with ground elevations ranging from sea level up to 500 m. Compared with the ground truth from a filtered inertial measurement unit (IMU)/GPS solution, the standard deviation for the pitch and roll angle errors obtained with 30 Mpixel images are 0.04° and 0.05°, respectively, with mean errors smaller than 0.02°. To achieve the high-accuracy attitude estimates, the ray refraction in the earth's atmosphere has been taken into account. The attitude errors obtained on real images are less or equal to those achieved on synthetic images for previous methods with DEM refinement, and the errors are about one order of magnitude smaller than for any previous vision-based method without DEM refinement.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2016
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-108212 (URN)10.1002/rob.21639 (DOI)000387925400005 ()
    Note

    At the date of the thesis presentation was this publication a manuscript.

    Funding agencies: Swedish Governmental Agency for Innovation Systems, VINNOVA [NFFP5 2013-05243]; Swedish Foundation for Strategic Research [RIT10-0047]; Swedish Research Council within the Linnaeus environment CADICS; Knut and Alice Wallenberg Foundation

    Available from: 2014-06-26 Created: 2014-06-26 Last updated: 2019-04-12Bibliographically approved
    4. Improved Learning in Convolutional Neural Networks with Shifted Exponential Linear Units (ShELUs)
    Open this publication in new window or tab >>Improved Learning in Convolutional Neural Networks with Shifted Exponential Linear Units (ShELUs)
    2018 (English)In: 2018 24th International Conference on Pattern Recognition (ICPR), IEEE, 2018, p. 517-522Conference paper, Published paper (Refereed)
    Abstract [en]

    The Exponential Linear Unit (ELU) has been proven to speed up learning and improve the classification performance over activation functions such as ReLU and Leaky ReLU for convolutional neural networks. The reasons behind the improved behavior are that ELU reduces the bias shift, it saturates for large negative inputs and it is continuously differentiable. However, it remains open whether ELU has the optimal shape and we address the quest for a superior activation function.We use a new formulation to tune a piecewise linear activation function during training, to investigate the above question, and learn the shape of the locally optimal activation function. With this tuned activation function, the classification performance is improved and the resulting, learned activation function shows to be ELU-shaped irrespective if it is initialized as a RELU, LReLU or ELU. Interestingly, the learned activation function does not exactly pass through the origin indicating that a shifted ELU-shaped activation function is preferable. This observation leads us to introduce the Shifted Exponential Linear Unit (ShELU) as a new activation function.Experiments on Cifar-100 show that the classification performance is further improved when using the ShELU activation function in comparison with ELU. The improvement is achieved when learning an individual bias shift for each neuron.

    Place, publisher, year, edition, pages
    IEEE, 2018
    Series
    International Conference on Pattern Recognition
    Keywords
    CNN, activation function
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-151606 (URN)10.1109/ICPR.2018.8545104 (DOI)000455146800087 ()978-1-5386-3787-6 (ISBN)
    Conference
    24th International Conference on Pattern Recognition, ICPR 2018, Beijing, China, 20-24 Aug. 2018
    Funder
    Wallenberg Foundations
    Note

    Funding agencies:  Wallenberg AI, Autonomous Systems and Software Program (WASP) - Knut and Alice Wallenberg Foundation; Swedish Research Council [2014-6227]

    Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2019-04-12
  • Arklid, Charlotte
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning.
    Fernqvist, August
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    En litteraturstudie om hur visuellt stöd främjar elever problemlösningsförmåga2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetet är en systematisk litteraturstudie och syftar till att undersöka vilken effekt diagram och bilder har på elevers problemlösningsförmåga. Det utvalda temat anser vi är viktigt eftersom många elever har svårt för problemlösning som helhet men även dess olika processer. Processerna innebär att; förstå problemet, ta ut viktig information, beräkna samt val av strategi. Därför granskades tidigare arbeten för att få en bredare kunskap om hur vi i framtiden kan underlätta för eleverna i arbetet med problemlösning. Problemlösning är även ett centralt område i läroplanenen där detnämns i det centrala innehållet, syftet samt förmågorna. Urvalet av artiklar gjordes genom manuell sökning och databassökning. I arbetet gjordes även avgränsningar, alla undersökningarna skulle vara granskade och fokusera på åldersspannet årskurs ett tillsex. Resultatet tyder i huvudsak på att diagram och bilder främjar elevernas kunskapsutveckling. De granskade artiklarna visar även att lärarna saknar tillräcklig förståelse för användning av visuella hjälpmedel i samband med problemlösning. Av den anledningen blir undervisningen till viss del bristande.

  • Hanqvist, Karolina
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Frisk, Sara
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Arbetssätt för skrivutveckling: En litteraturstudie som belyser arbetssätt för skrivundervisning samt effekter på skrivutvecklingen för årskurserna F–32019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna litteraturstudie är att undersöka vilka arbetssätt lärare kan använda sig av för att undervisa i skrivande, samt vilka effekter elevernas skrivutveckling kan få av skrivundervisningen.

     

    Det här arbetet baserades på informationen från 11 artiklar som analyserades och sammanställdes. Dessa hittades i databaserna UniSearch samt ERIC med relevanta sökord och avgränsningar.

     

    Resultatet visar fem exempel på arbetssätt lärare kan använda sig av för att undervisa i skrivande. Dessa var att arbeta med autentiska uppgifter, elevnära uppgifter, modellering, multimodala verktyg samt ett aktivt samarbete mellan individer. Arbetssätten och metoderna ledde fram till olika effekter inom elevers skrivutveckling, vilket kategoriserades i fem teman. Det som påverkades var skrivintresset, strukturen, innehållet, skriftspråket samt handskriften.

     

    Analysen av resultatet indikerade att det är viktigt att lärare har en utgångspunkt och ett syfte de förhåller sig till i deras undervisning. Med andra ord planera vilket arbetssätt de ska använda sig av för att nå ut till klassen. Elever lär på olika sätt och därmed behövs en variation mellan flera olika arbetssätt, för att nå alla individer och alla aspekter inom skrivande.