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  • 8651.
    Berg, Johan
    et al.
    Lund Univ, Sweden.
    Lundh, Lars-Gunnar
    Lund Univ, Sweden.
    Falkenström, Fredrik
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Countertransference in Swedish psychotherapists: testing the factor structure of the Therapist Response Questionnaire2019In: RESEARCH IN PSYCHOTHERAPY-PSYCHOPATHOLOGY PROCESS AND OUTCOME, ISSN 2239-8031, Vol. 22, no 1, p. 99-112Article in journal (Refereed)
    Abstract [en]

    Questionnaires need testing of reliability and factor structure before clinical use or research in new languages or cultures. The aim of this study was to evaluate the Therapist Response Questionnaire (TRQ) in Sweden compared to corresponding factor analyses in USA and Italy. A national sample of psychotherapists (N=242) registered their countertransference with a single client using TRQ. The data were analyzed with confirmatory factor analysis (CFA) to test factor structures from previous studies, and exploratory factor analysis (EFA). The CFA did not verify the factor structure from the previous studies. The EFA extracted seven factors as the best solution: Helpless/Inadequate, Overwhelmed/Disorganized, Hostile/Angry, Parental/Protective, Disengaged, Special/Overinvolved, Sex-ualized. Analysis of convergent validity indicated that five of these could be considered equivalent to factors in the previous studies, and the remaining two were conceptually related to corresponding factors. Even though the factor structure was not confirmed by the CFA, the concordance was large, indicating a reliable self-report instrument with promising validity for measurement of complex aspects of countertransference. Common countertransference themes can inform psychotherapy supervision and education, give feedback to the therapist, and lay ground for a taxonomy for therapist reactions and feelings.

  • 8652.
    Berg, Jonatan
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Magdesjö, Fredrik
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Vems behov styr valet av ett standardiserat informationssystem?: En studie över vems behov som styr när ett standardiserat informationssystem ska passa olika behov i organisationen2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Informationssystem används i organisationer för att fylla olika slags behov. Den här uppsatsensyftar till att undersöka hur dessa behov påverkar valet av informationssystem, samt hur dessabehov uppfylls av informationssystemet. För att utforska dessa behov användes enlitteraturstudie tillsammans med en empiriskt grundad kvalitativ undersökning. Dendatainsamlingsmetod som användes för att samla in empirin var en fallstudie hos Motalakommun, som genom kvalitativa semistrukturerade intervjuer beskrev de olikaverksamheternas behov i organisationen samt organisationens övergripande behov.

    Behovet som organisationer har av informationssystem beskrivs i teorin, där det ska användasför att stödja användarnas arbetsuppgifter. Arbetsuppgifterna kan sedan skilja sig åt beroendepå i vilken verksamhet inom organisationen som användaren arbetar inom. Litteraturenbeskriver även att de olika verksamheterna kan ha haft olika mycket inflytande på valet avinformationssystem, vilket gör att olika verksamheter fått sina behov mer uppfyllda avinformationssystemet än vad andra verksamheter inom organisationen kan ha fått.

    I den empiriska studien utforskades ett standardiserat informationssystem vilket ska användasav användare i samtliga verksamheter inom organisationen. De olika verksamheterna bidrogmed sina behov vid valet av informationssystemet, där tillgänglighet för organisationensmedborgare och underlag till statistik var två stora och gemensamma behov mellanverksamheterna. Empirin visade även på ouppfyllda behov samt oanade behov sominformationssystemet uppfyllde. De oanade behoven var i form av funktioner sominformationssystemet bidrog med vilka verksamheterna först identifierade vid användandet avinformationssystemet. Empirin gav även bilden av att en särskild verksamhets behov har varitdominanta över övriga verksamheters behov, vilket ledde till att denna verksamhetsarbetsuppgifter fått större stöd av informationssystemet än vad övriga verksamhetersarbetsuppgifter fått.

    Litteraturstudien gav på så vis ett resultat som liknande den empiriska undersökningen.Mycket av det som går att finna i tidigare forskning går att finna i verkligheten, i alla fallinom den organisation som vi studerade.

  • 8653.
    Berg, K
    et al.
    Norwegian University of Science and Technology.
    Skarra, S
    Norwegian University of Science and Technology.
    Bruvold, M
    Norwegian University of Science and Technology.
    Brurok, H
    Norwegian University of Science and Technology.
    Karlsson, JOG
    Norwegian University of Science and Technology.
    Jynge, Per
    Linköping University, Department of Medicine and Health Sciences. Linköping University, Faculty of Health Sciences.
    Iodinated radiographic contrast media possess antioxidant properties in vitro2005In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 46, no 8, p. 815-822Article in journal (Refereed)
    Abstract [en]

    Purpose: To study potential properties of iodinated radiographic contrast media (IRCM) for intravascular use in in vitro free radical generating reactions. Material and Methods: Superoxide (center dot O-2(-)) and hydroxyl ((OH)-O-center dot) radicals were generated in xanthine oxidase and Fenton reactions. center dot O-2(-) was assayed by the nitroblue tetrazolium (NBT) method, whereas (OH)-O-center dot was assayed by an aromatic hydroxylation (2-hydroxybenzoic acid) method. Total antioxidant status (TAS) of test substances was determined by a colorimetric assay. Finally, acetyl-cholinesterase (AChE) activity was measured in the absence and presence of IRCM. Results: High concentrations (greater than50 mM) of IRCM inhibited center dot O-2(-) production, ionic more than non-ionic IRCM. Medium concentrations (25-50 mM) of IRCM reduced (OH)-O-center dot production, and both types of IRCM were equally potent. Low concentrations (less than25 mM) of non-ionic IRCM displayed higher antioxidant capacity than their ionic counterparts when tested in the TAS assay. Visipaque 320 (iodixanol) was found to have the highest TAS value, followed by Omnipaque 350(R) (iohexol), Hexabrix 320(R) (ioxaglate), and Urografin 370(R) (diatrizoate). Conclusion: IRCM have in vitro antioxidant properties in concentrations relevant for their clinical application. These properties may therefore be of potential importance when evaluating IRCM effects in vivo, particularly those concerning cardiovascular and renal function.

  • 8654.
    Berg, Karin
    Linköping University, Department of Thematic Studies.
    Simulations of groundwater levels and soil water content: Development of a conceptual hydrological model with a continous soil profile2003Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [en]

    Transport of chemical substances through a catchment depend to a large extent on the water content of the soil through which they are transported. When the groundwater level rise and fall, redox conditions change in the soil and the transport of substances is affected.

    The aim of this study is to develop a hydrological model which is able to simulate soil water content at different depths and groundwater level in a soil profile. A new type of conceptual model is developed, which uses a continous represenation of the soil and soil water from the soil surface down to the bedrock. The model is intended to be applied on small catchments at a later stage.

    The results show that the simulation of groundwater levels was greatly improved compared to previous results. Simulation of soil water content at selected depths is not yet satisfactory. The runoff simulation was accurate at one of the sites but did not work as well at the other. At one of the sites it was also possible to combine good simulations of runoff and groundwater levels but at the other it was only possible to obtain acceptable simulations of either runoff or groundwater.

    It is suggested that model performance could be improved by letting the porosity decrease and the soil water content increase non-linearly with depth. Calculations of evaporation from soil and runoff also need to be modified.

  • 8655.
    Berg, Karin
    Linköping University, Department of Thematic Studies.
    Utveckling av en HBV/PULS-model med sammanfogade markfuktighets- och responsrutiner2002Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    Soil properties affect the chemical composition of soil water. When studying transport of chemical substances through a basin, it is therefore important to know from which soil layer the main part of the runoff is generated. The aim of this study is to develop an HBV/PULSE model with merged soil moisture and response routines, which generates good approximations of groundwater levels. It should be possible to extend the model to simulate transport of substances and take into account which soil layer the groundwater level is currently in.

    The hydrological version of HBV/PULSE is used since there is no need to account for pH or alcalinity at this stage. Representation of runoff is changed to an equation analogous to that of HBV-96. The unsaturated and saturated zones in the response routines are merged by associating change in groundwater storage with change in the size of the unsaturated zone. Field capacity, which is expressed in mm in the existing model, is transformed from parameter to variable. Three models are compared in this study: HBV/PULSE without any modifications, HBV/PULSE with a response function similar to that of HBV-96 and finally a model with the same response function as model two, variable field capacity, groundwater level simulation and connected soil moisture and response compartments.

    Results show that runoff is simulated equally well by the two first model versions, and alomst as well by the third. Soil moisture simulations show the same patterns for all three models, but slightly different levels. Ground water storage is different in the first model compared to the others, mainly depending on the use of capillary flux andnegative storage values in the unmodified model. Groundwater simulations with the third model generated results which differed much from measurements. The main problem is the magnitude of the variations which is far too small in the simulations.

    Introduction of variable soil moisture in the unsaturated zone and variable soil porosity is suggested as a way of increasing the magnitude of fluctuations in groundwater storage and levels. It is also necessary to allow groundwater storage, and thereby groundwater levels, to vary equally in both directions from the initial values. If this is not possible to achieve with the new response function, it is necessary to change back to the old function despite the increase in parameters.

  • 8656. Berg, Karin
    et al.
    Nyström, Kaj
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory.
    Hydrological Modeling in Modelica2005In: 4th International Modelica Conference, March 2005,2005, 2005Conference paper (Other academic)
  • 8657.
    Berg, Katarina
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Patients’ perspectives on recovery from day surgery2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A large number of elective surgical patients in Sweden and elsewhere have their surgical procedure performed in a day surgery context. The surgical care event, with its postoperative surveillance, is brief at the surgery unit and patients are discharged home with the intention that they should manage postoperative recovery mainly themselves. However, several patients attest to being in an exposed situation when assuming responsibility for recovery at home. The overall aim of this thesis was to attain comprehensive knowledge of postoperative recovery following day surgery from a patient perspective.

    A questionnaire, the Post-discharge Surgical Recovery scale, was translated into Swedish and evaluated regarding its psychometric properties in a Swedish context. A sample of 607 day surgery patients who had undergone orthopaedic, general or gynaecological surgery self-rated their recovery at postoperative Days 1, 7 and 14 using the Post-discharge Surgical Recovery scale and the Quality of Recovery-23. Health-related quality of life was assessed before and 30 days after the surgical procedure, using the EQ-5D. In a second sample, 31 patients were interviewed in their homes regarding their recovery after day surgery. The interviews were conducted on postoperative Days 11-37, and focused on the meaning of recovery, self-care and perceptions of recovery. Data were explored by means of a phenomenographic analysis.

    The Post-discharge Surgical Recovery scale showed satisfactory psychometric properties when used among Swedish day surgery patients. Following discharge, recovery included both physical and emotional perspectives. Recovery varied, and influencing factors were found to be type of surgery, age, perceived health and emotional status on the first postoperative day. Orthopaedic patients had a more protracted recovery process compared to general surgery and gynaecological patients, along with more postoperative pain and lower health-related quality of life. Patients perceived that postoperative recovery comprised different internal and external factors and a large amount of responsibility regarding their recovery and surgical outcome. To be prepared for recovery at home, patients wanted knowledge and understanding about the normal range of recovery following their specific surgical procedure, and needed support from different sources in their surroundings.

    This thesis provides insight into day surgery patients’ postoperative situation. Based on the studies, individualized and well thought-out support appears favourable in order to have confident and well prepared patients at home. In contrast to smooth and easy patient care at the surgery unit, the postoperative phase seems to be a weak link in the day surgical continuity of patient care. Postoperative care needs to be further improved to increase quality and patients’ overall satisfaction with the day surgical experience. Attention should be paid to patients’ physical and emotional resources and needs.

    List of papers
    1. Psychometric evaluation of the post-discharge surgical recovery scale
    Open this publication in new window or tab >>Psychometric evaluation of the post-discharge surgical recovery scale
    Show others...
    2010 (English)In: Journal of Evaluation In Clinical Practice, ISSN 1356-1294, E-ISSN 1365-2753, Vol. 16, no 4, p. 794-801Article in journal (Refereed) Published
    Abstract [en]

    Rationale, aim and objectives Day surgery patients are discharged after a short period of postoperative surveillance, and reliable and valid instruments for assessment at home are needed. The aim of this study was to evaluate the psychometric properties of a Swedish version of the post-discharge surgical recovery (PSR) scale, an instrument to monitor the patients recovery after day surgery, in terms of data quality, internal consistency, dimensionality and responsiveness. Methods Data were collected on postoperative days 1 and 14 and included 525 patients. Data quality and internal consistency were evaluated using descriptive statistics, correlation analyses and Cronbachs alpha. The dimensionality of the scale was determined through an exploratory factor analysis. Responsiveness was evaluated using the standardized response mean and the area under the receiver operating characteristics curve (AUC). The correlation between change score in PSR and change score in self-rated health was assessed using Pearsons correlation coefficient. Patients ability to work and their self-rated health on postoperative day 14 were used as external indicators of change. Results Six items showed floor or ceiling effects. Cronbachs coefficient alpha was 0.90 and the average inter-item correlation coefficient was 0.44 after the deletion of two items. The items were closely related to each other, and a one-factor solution was decided on. A robust ability to detect changes in recovery (standardized response mean = 1.14) was shown. The AUC for the entire scale was 0.60. When initial PSR scores were categorized into three intervals, the ability to detect improved and non-improved patients varied (AUC 0.58-0.81). There was a strong correlation between change scores in PSR and health (0.63). Conclusions The Swedish version of the PSR scale demonstrates acceptable psychometric properties of data quality, internal consistency, dimensionality and responsiveness. In addition to previous findings, these results strengthen the PSR scale as a potential instrument of recovery at home.

    Place, publisher, year, edition, pages
    Blackwell Publishing Ltd, 2010
    Keywords
    day surgery; postoperative period; psychometrics; questionnaire; recovery; validation study
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-58188 (URN)10.1111/j.1365-2753.2009.01197.x (DOI)000279901700019 ()
    Note

    This is the authors’ version of the following article: Katarina Berg, Ewa Idvall, Ulrica Nilsson, Kristofer Franzén Årestedt and Mitra Unosson, Psychometric evaluation of the post-discharge surgical recovery scale, 2010, Journal of Evaluation In Clinical Practice, (16), 4, 794-801. which has been published in final form at: http://dx.doi.org/10.1111/j.1365-2753.2009.01197.x Copyright: Blackwell Publishing Ltd http://eu.wiley.com/WileyCDA/Brand/id-35.html

    Available from: 2010-08-11 Created: 2010-08-09 Last updated: 2017-12-12Bibliographically approved
    2. Postoperative recovery after different orthopedic day surgical procedures
    Open this publication in new window or tab >>Postoperative recovery after different orthopedic day surgical procedures
    2011 (English)In: International Journal of Orthopaedic and Trauma Nursing, ISSN 1878-1241, E-ISSN 1878-1292, Vol. 15, no 4, p. 165-175Article in journal (Refereed) Published
    Abstract [en]

    Orthopedic day surgery is common. Postoperative recovery may differ according to surgical procedures and personal factors. We studied postoperative recovery up to 2 weeks after different orthopedic day surgical procedures and tried to identify possible predictors associated with recovery. Three-hundred and fifty eight patients who had undergone knee arthroscopy or surgery to the hand/arm, foot/leg or shoulder were included. Data were collected on postoperative days 1, 7 and 14 using the Swedish Post-discharge Surgery Recovery scale, the emotional state, physical comfort and physical independence dimensions in the Quality of Recovery-23 and a general health question. Multiple linear regression was used to explore predictors of recovery. The shoulder patients experienced significantly lower postoperative recovery and general health 1 and 2 weeks after surgery compared to the other patient groups (p < 0.001). Significant predictors of recovery were age, perceived health and emotional status on the first postoperative day and type of surgery. Postoperative recovery after common orthopedic day surgical procedures varies and factors influencing it need to be further explored. The impact of a patient’s emotional state on recovery after day surgery can be of particular interest in this work. Post-discharge planning needs to be tailored to the surgical procedure.

    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2011
    Keywords
    Day surgery; Postoperative recovery; Orthopedic nursing
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-71363 (URN)10.1016/j.ijotn.2011.02.003 (DOI)
    Available from: 2011-10-13 Created: 2011-10-13 Last updated: 2017-12-08
    3. Postoperative recovery and its association with health-related quality of life among day surgery patients
    Open this publication in new window or tab >>Postoperative recovery and its association with health-related quality of life among day surgery patients
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Background: Day surgery holds advantages for both the patient and the health care organization. However, recovery beyond the first postoperative week and following different types of surgery has not been explored to any greater degree. The current aims were to prospectively describe postoperative recovery and health-related quality of life among different groups of day surgery patients and to explore the association between postoperative recovery and health-related quality of life 30 days after discharge. A consecutive sample of 607 adult day surgery patients undergoing orthopaedic, gynaecological or general surgery was included. Postoperative recovery was assessed on days 1, 7 and 14 using the Swedish Post-discharge Surgery Recovery scale and the Quality of Recovery-23 scale. The EQ-5D was used to assess health-related quality of life preoperatively and 30 days following discharge. A repeated measure ANOVA was conducted to evaluate postoperative recovery from day 1 to day 14 and between different surgical groups. Hierarchical multiple linear regression models were used to explore the association between postoperative recovery and health-related quality of life.

    Results: Postoperative recovery improved from day 1 to 14 in all surgical groups (p<0.001). The orthopaedic patients had lower postoperative recovery on day 14 compared to the general and the gynaecological patients (p<0.001). Health-related quality of life was lower among orthopaedic patients (p<0.001), even if significant improvements over time were seen in all groups. Recovery on day 7 was associated with health-related quality of life 30 days after the day surgery (p<0.05).

    Conclusion: Particularly orthopaedic day surgical patients seem to favour a closer follow-up in order to support recovery and thereby also positively influence health-related quality of life.

    Keywords
    Ambulatory surgical procedures, nursing, quality of life, recovery of function
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-85025 (URN)
    Available from: 2012-10-31 Created: 2012-10-31 Last updated: 2016-09-26Bibliographically approved
    4. Postoperative recovery from the perspective of day surgery patients: A phenomenographic study
    Open this publication in new window or tab >>Postoperative recovery from the perspective of day surgery patients: A phenomenographic study
    2013 (English)In: International Journal of Nursing Studies, ISSN 0020-7489, E-ISSN 1873-491X, Vol. 50, no 12, p. 1630-1638Article in journal (Refereed) Published
    Abstract [en]

    Background: Today, many patients undergo surgical procedures in a day surgery setting. The shift from inpatient care to care at the patient’s own home following discharge places various demands on patients and their families during the recovery process. There is a need for knowledge of how the postoperative recovery process is perceived, as research indicates a lack of support for patients managing recovery at home.

    Objectives: To explore day surgery patients’ perceptions of postoperative recovery.

    Design: A qualitative design with a phenomenographic approach was used.

    Methods and settings: Semi-structured interviews with 31 patients undergoing an orthopaedic, general or urologic day surgical procedure were carried out face-to-face at the patients’ homes, 11-37 days post-discharge. Patients were recruited from two day surgery settings: one private unit and one unit associated with a local county hospital.

    Results: The patients perceived postoperative recovery as comprising internal and external prerequisites and implied changes in ordinary life with varying levels of support. The organization at the day surgery unit, with its advantages and disadvantages, was perceived as having an impact on the subsequent recovery trajectory. The results are demonstrated in three descriptive categories: ‘Conditions for recovery at home’, The rollback to ordinary life’ and ‘Being a cog in a flow of care’.

    Conclusions: Postoperative recovery following day surgery implies, from the patients’ perspective, a migration from being a recipient of care at the day surgery unit to playing an active role, with extensive responsibility at home. To manage self-care confidently, postdischarge patients require knowledge and understanding of what constitutes the normal range in recovery following their specific surgical procedure.

    Place, publisher, year, edition, pages
    Elsevier, 2013
    Keywords
    Ambulatory surgical procedures, nursing, qualitative research, recovery of function, self care
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-85026 (URN)10.1016/j.ijnurstu.2013.05.002 (DOI)000327225300007 ()
    Note

    Funding agencies|ALF||County Council of Ostergotland, Sweden||Linkoping University||

    Available from: 2012-10-31 Created: 2012-10-31 Last updated: 2017-12-07Bibliographically approved
  • 8658.
    Berg, Katarina
    Linköping University, Department of Medicine and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Postoperative recovery in daysurgery: Evaluation of psychometric properties and clinical usefulness of a questionnaire in day surgery2010Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Day surgery has increased during recent decades in many countries and represents approximately 50% of surgical procedures performed in Sweden. Day surgery implies that the patient is admitted and operated on during the same day and discharged without an overnight stay at the surgery unit. Undergoing a day surgical procedure thereby means that the major part of the postoperative recovery takes place in the patient’s home, leaving the patient and his/her supportive network responsible for the postoperative care. Day surgery also implies that health care professionals have to adapt to outpatient care and find valid measurements for monitoring a patient’s recovery progress after discharge.

    Aims: The aim of Study I was to evaluate the psychometric properties of a translated version of the Post-discharge Surgical Recovery (PSR) scale in a Swedish day surgery sample in terms of data quality, internal consistency, dimensionality and responsiveness. The aim of Study II was to describe postoperative recovery on postoperative days 1, 7 and 14 after different orthopaedic day surgical procedures, as well as to identify possible predictors associated with postoperative recovery two weeks after surgery.

    Methods: Six-hundred and seven patients who had undergone an orthopaedic surgical procedure (n=358), general surgery (n=182) or gynaecological surgery (n=67) were included. To assess postoperative recovery, the PSR scale and the emotional state, physical comfort and physical independency dimensions of the Quality of Recovery-23 (QoR-23) were used. In addition, patients’ background data and self ratings of their ability to work or handle usual business and general health were obtained. Data were collected preoperatively and on postoperative days 1, 7 and 14. In Study I data quality and internal consistency were evaluated using descriptive statistics, correlation analyses and Cronbach’s alpha. The dimensionality was determined using an exploratory factor analysis, and the responsiveness was evaluated through the standardized response mean (SRM) and the area under the receiver operating characteristics curve (AUC). In Study II, patients’ postoperative recovery and general health were compared over time using Friedmann’s ANOVA and between surgical groups of patients using the Kruskal-Wallis test. To determine predictors of recovery, a multiple linear regression analysis was performed with the PSR score on postoperative day 14 as the dependent variable.

    Results: In Study I, two items were deleted from the Swedish version of the PSR scale. This was based on several low inter-item (<0.30) and item-total correlations (<0.40) and substantial ceiling effects (65%). After the deletion of two items, the Cronbach’s coefficient alpha was 0.90 and the average interitem correlation was 0.44. According to the factor analysis, a single dimension was found explaining the common variance to 44%. The SRM (1.14) indicated a robust ability to detect changes in recovery. The AUC was 0.60 for the entire scale, but varied (0.58-0.81) when the PSR score on postoperative day 1 was categorized into three intervals. In Study II, the shoulder patients experienced significantly lower postoperative recovery and general health one and two weeks after surgery (p<0.001). Significant predictors of recovery on postoperative day 14 were age, perceived health and emotional status on postoperative day 1 and type of surgery, and explained the dependent variable to 33%.

    Conclusions: The Swedish version of the PSR scale seems to be a consistent and valid instrument for the assessment of postoperative recovery at home in Sweden. The recovery process for orthopaedic day surgery patients differs, with shoulder surgery patients in particular showing poor recovery, which could be considered when day surgery patient education programmes are developed.

    List of papers
    1. Psychometric evaluation of the post-discharge surgical recovery scale
    Open this publication in new window or tab >>Psychometric evaluation of the post-discharge surgical recovery scale
    Show others...
    2010 (English)In: Journal of Evaluation In Clinical Practice, ISSN 1356-1294, E-ISSN 1365-2753, Vol. 16, no 4, p. 794-801Article in journal (Refereed) Published
    Abstract [en]

    Rationale, aim and objectives Day surgery patients are discharged after a short period of postoperative surveillance, and reliable and valid instruments for assessment at home are needed. The aim of this study was to evaluate the psychometric properties of a Swedish version of the post-discharge surgical recovery (PSR) scale, an instrument to monitor the patients recovery after day surgery, in terms of data quality, internal consistency, dimensionality and responsiveness. Methods Data were collected on postoperative days 1 and 14 and included 525 patients. Data quality and internal consistency were evaluated using descriptive statistics, correlation analyses and Cronbachs alpha. The dimensionality of the scale was determined through an exploratory factor analysis. Responsiveness was evaluated using the standardized response mean and the area under the receiver operating characteristics curve (AUC). The correlation between change score in PSR and change score in self-rated health was assessed using Pearsons correlation coefficient. Patients ability to work and their self-rated health on postoperative day 14 were used as external indicators of change. Results Six items showed floor or ceiling effects. Cronbachs coefficient alpha was 0.90 and the average inter-item correlation coefficient was 0.44 after the deletion of two items. The items were closely related to each other, and a one-factor solution was decided on. A robust ability to detect changes in recovery (standardized response mean = 1.14) was shown. The AUC for the entire scale was 0.60. When initial PSR scores were categorized into three intervals, the ability to detect improved and non-improved patients varied (AUC 0.58-0.81). There was a strong correlation between change scores in PSR and health (0.63). Conclusions The Swedish version of the PSR scale demonstrates acceptable psychometric properties of data quality, internal consistency, dimensionality and responsiveness. In addition to previous findings, these results strengthen the PSR scale as a potential instrument of recovery at home.

    Place, publisher, year, edition, pages
    Blackwell Publishing Ltd, 2010
    Keywords
    day surgery; postoperative period; psychometrics; questionnaire; recovery; validation study
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-58188 (URN)10.1111/j.1365-2753.2009.01197.x (DOI)000279901700019 ()
    Note

    This is the authors’ version of the following article: Katarina Berg, Ewa Idvall, Ulrica Nilsson, Kristofer Franzén Årestedt and Mitra Unosson, Psychometric evaluation of the post-discharge surgical recovery scale, 2010, Journal of Evaluation In Clinical Practice, (16), 4, 794-801. which has been published in final form at: http://dx.doi.org/10.1111/j.1365-2753.2009.01197.x Copyright: Blackwell Publishing Ltd http://eu.wiley.com/WileyCDA/Brand/id-35.html

    Available from: 2010-08-11 Created: 2010-08-09 Last updated: 2017-12-12Bibliographically approved
    2. Postoperativerecovery after different orthopaedic day surgical procedures
    Open this publication in new window or tab >>Postoperativerecovery after different orthopaedic day surgical procedures
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Orthopaedic day surgery is common. Postoperative recovery may differ according to surgical procedures and personal factors. We studied postoperative recovery up to two weeks after different orthopaedic day surgical procedures, and tried to identify possible predictors associated with recovery. Three-hundred and fifty-eight patients who had undergone knee arthroscopy or surgery on the hand/arm, foot/leg or shoulder were included. Data were collected preoperatively and on postoperative days 1, 7 and 14 using the Swedish Post-discharge Surgery Recovery scale, the emotional state, physical comfort and physical independence dimensions in the Quality of Recovery-23, and a general health question. A multiple linear regression was used to explore predictors of recovery. The shoulder patients experienced significantly lower postoperative recovery and general health one and two weeks after surgery compared to the other patient groups (p<0.001). Significant predictors of recovery were age, perceived health and emotional status on the first postoperative day, and type of surgery. Postoperative recovery after common orthopaedic day surgical procedures differs, and factors influencing it need to be further explored. The impact of a patient’s emotional state on recovery after day surgery can be of particular interest in this work. Post-discharge planning needs to be tailored to the surgical procedure.

    Keywords
    Day surgery, postoperative recovery, orthopaedic nursing
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-59513 (URN)
    Available from: 2010-09-17 Created: 2010-09-17 Last updated: 2010-09-17Bibliographically approved
  • 8659.
    Berg, Katarina
    et al.
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Franzén Årestedt, Kristofer
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences.
    Kjellgren, Karin
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Postoperative recovery from the perspective of day surgery patients: A phenomenographic study2013In: International Journal of Nursing Studies, ISSN 0020-7489, E-ISSN 1873-491X, Vol. 50, no 12, p. 1630-1638Article in journal (Refereed)
    Abstract [en]

    Background: Today, many patients undergo surgical procedures in a day surgery setting. The shift from inpatient care to care at the patient’s own home following discharge places various demands on patients and their families during the recovery process. There is a need for knowledge of how the postoperative recovery process is perceived, as research indicates a lack of support for patients managing recovery at home.

    Objectives: To explore day surgery patients’ perceptions of postoperative recovery.

    Design: A qualitative design with a phenomenographic approach was used.

    Methods and settings: Semi-structured interviews with 31 patients undergoing an orthopaedic, general or urologic day surgical procedure were carried out face-to-face at the patients’ homes, 11-37 days post-discharge. Patients were recruited from two day surgery settings: one private unit and one unit associated with a local county hospital.

    Results: The patients perceived postoperative recovery as comprising internal and external prerequisites and implied changes in ordinary life with varying levels of support. The organization at the day surgery unit, with its advantages and disadvantages, was perceived as having an impact on the subsequent recovery trajectory. The results are demonstrated in three descriptive categories: ‘Conditions for recovery at home’, The rollback to ordinary life’ and ‘Being a cog in a flow of care’.

    Conclusions: Postoperative recovery following day surgery implies, from the patients’ perspective, a migration from being a recipient of care at the day surgery unit to playing an active role, with extensive responsibility at home. To manage self-care confidently, postdischarge patients require knowledge and understanding of what constitutes the normal range in recovery following their specific surgical procedure.

  • 8660.
    Berg, Katarina
    et al.
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Idvall, Ewa
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Nilsson, Ulrica
    Örebro University Hospital.
    Franzén Årestedt, Kristofer
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences.
    Unosson, Mitra
    Linköping University, Department of Social and Welfare Studies, Division of Health, Activity and Care. Linköping University, Faculty of Health Sciences.
    Psychometric evaluation of the post-discharge surgical recovery scale2010In: Journal of Evaluation In Clinical Practice, ISSN 1356-1294, E-ISSN 1365-2753, Vol. 16, no 4, p. 794-801Article in journal (Refereed)
    Abstract [en]

    Rationale, aim and objectives Day surgery patients are discharged after a short period of postoperative surveillance, and reliable and valid instruments for assessment at home are needed. The aim of this study was to evaluate the psychometric properties of a Swedish version of the post-discharge surgical recovery (PSR) scale, an instrument to monitor the patients recovery after day surgery, in terms of data quality, internal consistency, dimensionality and responsiveness. Methods Data were collected on postoperative days 1 and 14 and included 525 patients. Data quality and internal consistency were evaluated using descriptive statistics, correlation analyses and Cronbachs alpha. The dimensionality of the scale was determined through an exploratory factor analysis. Responsiveness was evaluated using the standardized response mean and the area under the receiver operating characteristics curve (AUC). The correlation between change score in PSR and change score in self-rated health was assessed using Pearsons correlation coefficient. Patients ability to work and their self-rated health on postoperative day 14 were used as external indicators of change. Results Six items showed floor or ceiling effects. Cronbachs coefficient alpha was 0.90 and the average inter-item correlation coefficient was 0.44 after the deletion of two items. The items were closely related to each other, and a one-factor solution was decided on. A robust ability to detect changes in recovery (standardized response mean = 1.14) was shown. The AUC for the entire scale was 0.60. When initial PSR scores were categorized into three intervals, the ability to detect improved and non-improved patients varied (AUC 0.58-0.81). There was a strong correlation between change scores in PSR and health (0.63). Conclusions The Swedish version of the PSR scale demonstrates acceptable psychometric properties of data quality, internal consistency, dimensionality and responsiveness. In addition to previous findings, these results strengthen the PSR scale as a potential instrument of recovery at home.

  • 8661.
    Berg, Katarina
    et al.
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Idvall, Ewa
    Faculty of Health and Society, Malmö University.
    Nilsson, Ulrica
    Örebro University Hospital.
    Unosson, Mitra
    Linköping University, Department of Social and Welfare Studies, Health, Activity, Care. Linköping University, Faculty of Health Sciences.
    Postoperative recovery after different orthopedic day surgical procedures2011In: International Journal of Orthopaedic and Trauma Nursing, ISSN 1878-1241, E-ISSN 1878-1292, Vol. 15, no 4, p. 165-175Article in journal (Refereed)
    Abstract [en]

    Orthopedic day surgery is common. Postoperative recovery may differ according to surgical procedures and personal factors. We studied postoperative recovery up to 2 weeks after different orthopedic day surgical procedures and tried to identify possible predictors associated with recovery. Three-hundred and fifty eight patients who had undergone knee arthroscopy or surgery to the hand/arm, foot/leg or shoulder were included. Data were collected on postoperative days 1, 7 and 14 using the Swedish Post-discharge Surgery Recovery scale, the emotional state, physical comfort and physical independence dimensions in the Quality of Recovery-23 and a general health question. Multiple linear regression was used to explore predictors of recovery. The shoulder patients experienced significantly lower postoperative recovery and general health 1 and 2 weeks after surgery compared to the other patient groups (p < 0.001). Significant predictors of recovery were age, perceived health and emotional status on the first postoperative day and type of surgery. Postoperative recovery after common orthopedic day surgical procedures varies and factors influencing it need to be further explored. The impact of a patient’s emotional state on recovery after day surgery can be of particular interest in this work. Post-discharge planning needs to be tailored to the surgical procedure.

  • 8662.
    Berg, Katarina
    et al.
    Linköping University, Department of Medicine and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Idvall, Ewa
    Linköping University, Department of Medicine and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Nilsson, Ulrica
    Linköping University, Department of Medicine and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Unosson, Mitra
    Linköping University, Department of Medicine and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Postoperativerecovery after different orthopaedic day surgical proceduresManuscript (preprint) (Other academic)
    Abstract [en]

    Orthopaedic day surgery is common. Postoperative recovery may differ according to surgical procedures and personal factors. We studied postoperative recovery up to two weeks after different orthopaedic day surgical procedures, and tried to identify possible predictors associated with recovery. Three-hundred and fifty-eight patients who had undergone knee arthroscopy or surgery on the hand/arm, foot/leg or shoulder were included. Data were collected preoperatively and on postoperative days 1, 7 and 14 using the Swedish Post-discharge Surgery Recovery scale, the emotional state, physical comfort and physical independence dimensions in the Quality of Recovery-23, and a general health question. A multiple linear regression was used to explore predictors of recovery. The shoulder patients experienced significantly lower postoperative recovery and general health one and two weeks after surgery compared to the other patient groups (p<0.001). Significant predictors of recovery were age, perceived health and emotional status on the first postoperative day, and type of surgery. Postoperative recovery after common orthopaedic day surgical procedures differs, and factors influencing it need to be further explored. The impact of a patient’s emotional state on recovery after day surgery can be of particular interest in this work. Post-discharge planning needs to be tailored to the surgical procedure.

  • 8663.
    Berg, Katarina
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nursing Science.
    Idvall, Ewa
    Linköping University, Department of Medicine and Care.
    Unosson, Mitra
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nursing Science.
    Postoperative recovery for day surgery patients2004In: 12th Biennal Conference of the Workgroup of European Nurse Researchers,2004, 2004, p. 77-77Conference paper (Other academic)
  • 8664.
    Berg, Katarina
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences.
    Kaspersen, Rikard
    Sykehuset Osffold HF, Norway .
    Unby, Christina
    Sirius Humanum AB, Sweden .
    Hollman Frisman, Gunilla
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology.
    The Interaction Between the Patient and Nurse Anesthetist Immediately Before Elective Coronary Artery Bypass Surgery2013In: Journal of Perianesthesia Nursing, ISSN 1089-9472, E-ISSN 1532-8473, Vol. 28, no 5, p. 283-290Article in journal (Refereed)
    Abstract [en]

    Purpose: Establishing a purposive interaction with a patient who is in a vulnerable situation before coronary artery bypass graft (CABG) surgery poses a challenge for the nurse anesthetist. The aim of this study was to identify and describe the interaction between the patient and the nurse anesthetist immediately before elective CABG surgery. less thanbrgreater than less thanbrgreater thanDesign: An observational study using a grounded theory design was used. less thanbrgreater than less thanbrgreater thanMethods: A theoretical selection of patients and nurse anesthetists was made. A total of 11 situations of patient/nurse anesthetist interaction were observed. The data were analyzed using the constant comparative method. Findings:A core category of reassurance emerged from other categories of continuity, confirmation, and control. Continuity was characterized by expedient anesthesia nursing of high quality, confirmation was related to communication in a trusting atmosphere, and control was associated with skilled nursing interventions in the thoracic operating theatre. less thanbrgreater than less thanbrgreater thanConclusions: Reassurance can be achieved through a well-structured anesthesia nursing performance in the thoracic operating theatre, and by focusing on the patient and continuously giving him/her information during the preoperative preparation phase.

  • 8665.
    Berg, Katarina
    et al.
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Kjellgren, Karin
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Unosson, Mitra
    Linköping University, Department of Social and Welfare Studies, Health, Activity, Care. Linköping University, Faculty of Health Sciences.
    Franzén Årestedt, Kristofer
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Postoperative recovery and its association with health-related quality of life among day surgery patientsManuscript (preprint) (Other academic)
    Abstract [en]

    Background: Day surgery holds advantages for both the patient and the health care organization. However, recovery beyond the first postoperative week and following different types of surgery has not been explored to any greater degree. The current aims were to prospectively describe postoperative recovery and health-related quality of life among different groups of day surgery patients and to explore the association between postoperative recovery and health-related quality of life 30 days after discharge. A consecutive sample of 607 adult day surgery patients undergoing orthopaedic, gynaecological or general surgery was included. Postoperative recovery was assessed on days 1, 7 and 14 using the Swedish Post-discharge Surgery Recovery scale and the Quality of Recovery-23 scale. The EQ-5D was used to assess health-related quality of life preoperatively and 30 days following discharge. A repeated measure ANOVA was conducted to evaluate postoperative recovery from day 1 to day 14 and between different surgical groups. Hierarchical multiple linear regression models were used to explore the association between postoperative recovery and health-related quality of life.

    Results: Postoperative recovery improved from day 1 to 14 in all surgical groups (p<0.001). The orthopaedic patients had lower postoperative recovery on day 14 compared to the general and the gynaecological patients (p<0.001). Health-related quality of life was lower among orthopaedic patients (p<0.001), even if significant improvements over time were seen in all groups. Recovery on day 7 was associated with health-related quality of life 30 days after the day surgery (p<0.05).

    Conclusion: Particularly orthopaedic day surgical patients seem to favour a closer follow-up in order to support recovery and thereby also positively influence health-related quality of life.

  • 8666.
    Berg, Katarina
    et al.
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Kjellgren, Karin
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Unosson, Mitra
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Health Sciences.
    Årestedt, Kristofer
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Postoperative recovery and its association with health-related quality of life among day surgery patients2012In: BMC Nursing, ISSN 1472-6955, E-ISSN 1472-6955, Vol. 11, no 24Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Day surgery holds advantages for both the patient and the health care organization. However, recovery beyond the first Postoperative week and following different types of surgery has not been explored to any greater degree. The current aims were to prospectively describe Postoperative recovery and health-related quality of life among different groups of day surgery patients and to explore the association between Postoperative recovery and healthrelated quality of life 30 days after discharge.

    METHODS: A consecutive sample of 607 adult day surgery patients undergoing orthopaedic, gynaecological or general surgery was included. Postoperative recovery was assessed on days 1, 7 and 14 using the Swedish Post-discharge Surgery recovery scale and the quality of recovery-23 scale. The EQ-5D was used to assess health-related quality of life preoperatively and 30 days following discharge. A repeated measure ANOVA was conducted to evaluate Postoperative recovery from day 1 to day 14 and between different surgical groups. Hierarchical multiple linear regression models were used to explore the association between Postoperative recovery and health-related quality of life.

    RESULTS: Postoperative recovery improved from day 1 to 14 in all surgical groups (p<0.001). The orthopaedic patients had lower Postoperative recovery on day 14 compared to the general and the gynaecological patients (p<0.001). health-related quality of life was lower among orthopaedic patients (p<0.001), even if significant improvements over time were seen in all groups. recovery on day 7 was associated with health-related quality of life 30 days after the day surgery (p<0.05).

    CONCLUSION: Particularly orthopaedic day surgical patients seem to favour a closer follow-up in order to support recovery and thereby also positively influence health-related quality of life.

  • 8667.
    Berg, Kirsti
    et al.
    Norwegian University of Science and Technology, Trondheim, Norway.
    Ericsson, Madelene
    Umeå University, Sweden.
    Lindgren, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology. Norwegian University of Science and Technology, Trondheim, Norway.
    Gustafsson, Håkan
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Biomedical Engineering.
    A High Precision Method for Quantitative Measurements of Reactive Oxygen Species in Frozen Biopsies2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3Article in journal (Refereed)
    Abstract [en]

    Objective

    An electron paramagnetic resonance (EPR) technique using the spin probe cyclic hydroxylamine 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetr​amethylpyrrolidine(CMH) was introduced as a versatile method for high precision quantification of reactive oxygen species, including the superoxide radical in frozen biological samples such as cell suspensions, blood or biopsies.

    Materials and Methods

    Loss of measurement precision and accuracy due to variations in sample size and shape were minimized by assembling the sample in a well-defined volume. Measurement was carried out at low temperature (150 K) using a nitrogen flow Dewar. The signal intensity was measured from the EPR 1st derivative amplitude, and related to a sample, 3-carboxy-proxyl (CP•) with known spin concentration.

    Results

    The absolute spin concentration could be quantified with a precision and accuracy better than ±10 µM (k = 1). The spin concentration of samples stored at −80°C could be reproduced after 6 months of storage well within the same error estimate.

    Conclusion

    The absolute spin concentration in wet biological samples such as biopsies, water solutions and cell cultures could be quantified with higher precision and accuracy than normally achievable using common techniques such as flat cells, tissue cells and various capillary tubes. In addition; biological samples could be collected and stored for future incubation with spin probe, and also further stored up to at least six months before EPR analysis, without loss of signal intensity. This opens for the possibility to store and transport incubated biological samples with known accuracy of the spin concentration over time.

  • 8668.
    Berg, Kristoffer
    et al.
    Linköping University, Department of Management and Engineering.
    Lindholm, Jonas
    Linköping University, Department of Management and Engineering.
    Vibrationsisolering av gruvmaskinshytt2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The aim of this thesis, commissioned by Atlas Copco Rock Drills AB, is to investigate the vibration problems concerning the Scaletec MC and give proposals on new concept solutions that improve the handling of the vibration problems. The solutions are limited to the cabin and the cabins connection to the frame. The conclusion tells us that the most important issue is the long reaching boom with the hydraulic hammer attached to it. This assembly creates movements in the cabin during scaling and transportation. The non-damped transportation chair, the rough roads and the stiff axles are also factors that create problems with whole body vibrations.

    The concept phase focused on finding a robust and compact design that, with the correct degree of freedoms, reduces the influence of the vibrations. The result consists of two solutions, both controlling and managing the existing vibrations. The first solution focuses on the flaws that the existing system possesses and the other is designed to handle greater vibration levels.

  • 8669. Berg, L
    et al.
    Gustafsson, L
    Hansson, G
    Klingen, S
    Marcusson, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Geriatrics. Östergötlands Läns Landsting, MC - Medicincentrum, Geriatrik-LAH.
    Näsman, B
    Passant, U
    Wahlund, U
    Wallin, A
    Harmonisering av demensdiagnoser - en nödvändig kvalitetssäkring.2001In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 98, p. 3531-3535Article in journal (Other academic)
  • 8670.
    Berg, L K
    et al.
    Department of Anatomy, Institute of Basic Medical Sciences, Centre for Molecular, Biology and Neuroscience (CMBN), University of Oslo, Norway.
    Larsson, M
    Department of Anatomy, Institute of Basic Medical Sciences, Centre for Molecular, Biology and Neuroscience (CMBN), University of Oslo, Norway; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Morland, C
    Department of Anatomy, Institute of Basic Medical Sciences, Centre for Molecular, Biology and Neuroscience (CMBN), University of Oslo, Norway.
    Gundersen, V
    Department of Anatomy, Institute of Basic Medical Sciences, Centre for Molecular, Biology and Neuroscience (CMBN), University of Oslo, Norway; Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
    Pre- and postsynaptic localization of NMDA receptor subunits at hippocampal mossy fibre synapses.2013In: Neuroscience, ISSN 0306-4522, E-ISSN 1873-7544, Vol. 230, p. 139-150Article in journal (Refereed)
    Abstract [en]

    The N-methyl-D-aspartate (NMDA) type of glutamate receptors is involved in synaptic plasticity in hippocampal mossy fibre-CA3 pyramidal neuron synapses. The ultrastructural localization of NMDA receptor subunits at this synapse type is not known. By postembedding electron microscopic immunogold cytochemistry we show that the NMDA receptor subunits GluN1, GluN2A, GluN2B, GluN2C and GluN2D are located in postsynaptic membranes of mossy fibre as well as CA3 recurrent associational commissural synapses. In the mossy fibres the GluN1, GluN2B and GluN2D labelling patterns suggested that these subunits were located also presynaptically in nerve terminal membranes and in mossy fibre axons. GluN3B was predominantly present in mossy fibre synapses as compared to recurrent associational commissural synapses, showing a presynaptic labelling pattern. In conclusion, while the postsynaptic localization of GluN1, GluN2A, GluN2B, and GluN2D is in good agreement with the recent finding of NMDA receptor-dependent long term potentiation (LTP) at CA3 mossy fibre synapses, we propose that presynaptic GluN1, GluN2B, GluN2D and GluN3B subunits could be involved in plastic phenomena such as certain types of LTP and recurrent mossy fibre growth.

  • 8671.
    Berg, Linda
    et al.
    Centrum för Europaforskning (CERGU) / Statsvetenskapliga institutionen, Göteborgs universitet..
    Erlingsson, Gissur Ó
    Linköping University, Department for Studies of Social Change and Culture, Centre for Municipality Studies – CKS. Linköping University, Faculty of Arts and Sciences.
    Oscarsson, Henrik
    Statsvetenskapliga institutionen, Göteborgs universitet.
    Rekordhög röstdelning2019In: Storm och Stiltje / [ed] Ulrika Andersson, Björn Rönnerstrand, Patrik Öhberg & Annika Bergström, Göteborg: Förlag Göteborgs Universitet, 2019, p. 93-105Chapter in book (Other academic)
    Abstract [sv]

    En het frågeställning inom forskningen om väljarbeteende handlar om under vilka omständigheter och varför väljare fattar olika röstningsbeslut i samtidiga val till olika politiska nivåer: I vilken utsträckning är röstdelning ett uttryck för förvirring eller osäker riskspridning utifrån nationella överväganden bland väljarna, och i vad mån handlar det om sofistikerade väljares väl övervägda hänsyn till politiska omständigheter? För att kunna närma sig ett svar på dessa övergripande frågor behövs först en delstudie som noggrant kartlägger röstmönster i kommun- och riksdagsval. Röstdelningen i Sverige har åter slagit nytt rekord med omkring en tredjedel av väljarna som röstade på olika partier. Röstdelning tenderar idag att vara vanligare bland yngre, intresserade och högutbildade väljare som saknar starka band till politiska partier. Den vanligaste kombinationen vid det senaste riksdagsvalet 2018 var att rösta på Moderaterna lokalt och på Sverigedemokraterna nationellt. Resultaten indikerar att forskningens två huvudförklaringar till röstdelning inte är tillräckliga och att fördjupade analyser krävs för att bättre kunna sortera ut förklaringar till röstdelning och skilja ut olika typer av kommunala väljare.

  • 8672.
    Berg, Ludwig
    et al.
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies. Linköping University, The Institute of Technology.
    K. Engberg, Olle
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies. Linköping University, The Institute of Technology.
    Kollektion X: En möbelkollektion baserad på möbelhistoriska parenteser2013Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    The history of furniture is full of parentheses, furniture that appeared for short periods of time, was never a big hit, was forgotten or even disappeared. We were convinced that amongst all these more or less forgotten pieces of furniture there were examples worthy of rediscovery and renaissance. By examining these pieces of furniture, we have understood their history and context, found out and reflected upon why they where never more than a parenthesis in the history of furniture, and, last but not least, we have gained an understanding of the purpose of their creation and how they were used. Our ambition with this research - by creating a feeling and an understanding of the furniture - has been to find the pieces that are well suited to act as models for new concepts and products. By describing the furniture’s original purpose, functions and context, we saw opportunities for product updates and rearrangement of form and function. We have made a selection based on a story of a fictitious company, a small company planning to put on the market a coherent collection of exclusive furniture of high quality. The purpose of the collection is to inspire to use and to create stylish, restful places in your home. The concept of the collection guided the criteria and discussions that were the basis of the choices we made when particular pieces of furniture were selected to generate new concepts. The purpose of our work was to show a process of working where we, as cabinet-makers, by means of examining historic furniture, create a coherent collection based on historic models. Our work has resulted in a collection of four pieces of furniture that have been modeled in co-operation with external designers and architects.  

  • 8673.
    Berg, Magnus
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Social and Welfare Studies, Society, Diversity, Identity .
    Belägrade människor - belägrade rum2007In: RIG: Kulturhistorisk tidskrift, ISSN 0035-5267, E-ISSN 2002-3863, Vol. 3Article in journal (Other academic)
  • 8674.
    Berg, Magnus
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Social and Welfare Studies, Society, Diversity, Identity .
    Mia, Moa, kroppar, tankar, nytta2007In: Kulturella perspektiv - Svensk etnologisk tidskrift, ISSN 1102-7908, Vol. 1Article in journal (Other academic)
  • 8675.
    Berg, Magnus
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Arts and Sciences.
    Nicke2009In: Kulturellt: Reflektioner i Erling Bjurströms anda, Linköping: Linköping University Electronic Press , 2009, p. 26-26Chapter in book (Other (popular science, discussion, etc.))
  • 8676.
    Berg, Magnus
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Social and Welfare Studies, Society, Diversity, Identity .
    Recention av Ulf Hedetoft, Bo Petersson & Lina Sturfelt (red) Bortom stereotyperna2007In: RIG: Kulturhistorisk tidskrift, ISSN 0035-5267, E-ISSN 2002-3863, Vol. 4Article in journal (Other academic)
    Abstract [sv]

       

  • 8677.
    Berg, Martin
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Pose Recognition for Tracker Initialization Using 3D Models2008Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis it is examined whether the pose of an object can be determined by a system trained with a synthetic 3D model of said object. A number of variations of methods using P-channel representation are examined. Reference images are rendered from the 3D model, features, such as gradient orientation and color information are extracted and encoded into P-channels. The P-channel representation is then used to estimate an overlapping channel representation, using B1-spline functions, to estimate a density function for the feature set. Experiments were conducted with this representation as well as the raw P-channel representation in conjunction with a number of distance measures and estimation methods.

    It is shown that, with correct preprocessing and choice of parameters, the pose can be detected with some accuracy and, if not in real-time, fast enough to be useful in a tracker initialization scenario. It is also concluded that the success rate of the estimation depends heavily on the nature of the object.

  • 8678.
    Berg, Matilda
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Rozental, Alexander
    Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden; Institute of Child Health, University College London, London, United Kingdom of Great Britain and Northern Ireland.
    Johansson, Sofie
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Liljethorn, Lina
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Radvogin, Ella
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Topooco, Naira
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Andersson, Gerhard
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences. Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden.
    The role of knowledge in internet-based cognitive behavioural therapy for adolescent depression: Results from a randomised controlled study2019In: Internet Interventions, ISSN 2214-7829, Vol. 15, p. 10-17Article in journal (Refereed)
    Abstract [en]

    Background and objectives

    Clients' knowledge about their condition and treatment is considered crucial for general health improvement, and knowledge acquisition is an essential part in internet-based cognitive behavioural therapy (ICBT). Yet, little is known about the role of knowledge and how it influences treatment outcome. This study aimed to examine if explicit knowledgeincreased following ICBT for adolescent depression, if knowledge gainwould be associated with symptom reduction, and if pre-existing knowledge predicted changes in depressive symptoms.

    Methods

    Seventy-one adolescents were randomised to a therapist-supported ICBT or a attention control condition. A measure of depression (BDI-II) and a knowledge test dealing with depression, comorbid anxiety, and its CBT-treatment were administered before and after treatment.

    Results

    Significant improvements in knowledge were observed following ICBT compared to the attention control (between-group Cohen's d = 1.25, 95% CI [0.67–1.79]). On average, participants in the treatment group answered 1.4 more questions correctly at post treatment compared to the control group. No relation between change in knowledge and change in depressive symptoms could be observed. Knowledge scores at baseline were high for both groups, with participants answering approximately 75% of the questions correct. A higher level of initial knowledge level predicted poorer treatment response (Parson's r = −0.38, p = .048).

    Conclusions

    The findings indicate that knowledge about basic concepts and principles about depression, anxiety, and CBT increases following ICBT. This increase in knowledge was not related to change in depressive symptoms, indicating that knowledge is a different construct. The results also suggest that clients who are more knowledgeable prior to treatment might benefit less from ICBT. In sum, the results highlight the need to further examine the role of knowledge in ICBT.

  • 8679.
    Berg, Monica
    Linköping University, Department of Educational Science (IUV).
    Kemilaborationer: Hur elever och deras lärare uppfattar det laborativa arbetssättet under år fyra och fem2000Independent thesis Basic level (professional degree)Student thesis
    Abstract [sv]

    Syftet med detta arbete är att undersöka hur elever och deras lärare uppfattar kemi-laborationer. Genom litteraturstudier har jag sökt vad som ligger till grund för det laborativa arbetssättet. Jag har därefter använt mig av en kvalitativ metod och intervjuat sju elever samt deras klasslärare, i år fyra och fem, om hur de upplevt ett antal kemilaborationer och vad de lärt sig genom att utföra dessa. De flesta elever tyckte att det var roligt att laborera. De kom ihåg vad de hade gjort, men visste oftast inte varför resultatet blev som det blev. Deras egen uppfattning av vad de själva lärt sig var ofta inte kopplat till laborationerna, utan till lärarens teorigenomgångar. Läraren var positiv till arbetssättet och såg framförallt en fördel med att det förde med sig andra sidoeffekter än att just förstå kemin, t.ex. samarbetsträning och övning i själva utförandet.

  • 8680.
    Berg, Märta
    et al.
    Naturskyddsföreningen, Stockholm.
    Fägerstam, Emilia
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science. Linköping University, Faculty of Arts and Sciences.
    Utvärdering. Skogen som klassrum: Utvärdering av projektet 2009-20122013Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Följande rapport är en utvärdering av projekt Skogen som klassrum som har bedrivits gemensamt av Naturskyddsföreningen och Naturskoleföreningen under 2009-2012. Projektet har bestått av en fortbildning i utomhuspedagogik för pedagoger kallad Skogen som klassrum samt aktiviteter på lokal, regional och nationell nivå för att uppmärksamma värdet av undervisning i skogen och behovet av att tillgängliggöra och bevara skogar nära skolor och bostäder.

    Projektet har lyft frågor och startat processer som har förbättrat förutsättningarna för att tusentals lärare och elever ska ha möjlighet att vistas i och lära känna skogen under skoltid. Utvärderingen visar att även en förhållandevis kort fortbildning som Skogen som klassrum bidrar till en utökad och fördjupad undervisning i naturen. Samtidigt kan fortbildningens upplägg med undervisning i och om närliggande skogsområden ha en positiv inverkan på lärarnas möjlighet att uppfylla målen i skolans styrdokument. En fortbildning som Skogen som klassrum kan på detta sätt vara en viktig del i arbetet för lärande för hållbar utveckling.

    Det finns ett stort intresse för en fortsättning av projektet. Många aktörer inomSkogen som klassrum uttrycker att projektet har varit lärorikt och roligt och man ser det positiva i att integrera frågor kring skogens biologiska och sociala värden med skogens möjligheter som pedagogisk resurs i olika skolämnen. För att undervisning i naturen ska bli en naturlig del av skolans verksamhet i alla Sveriges kommuner krävs fortsatt arbete för att myndigheter och politiker ska ge stöd till utomhuspedagogisk verksamhet. Dessutom måste naturområden nära skolor bevaras och göras lättillgängliga. I längden kan undervisning i naturen leda till ett ökat intresse för växter och djur och att vara ute i naturen på fritiden. Detta kan i sin tur leda vidare till ett ökat intresse för att bevara natur och ett engagemang för samhällets hållbara utveckling.

  • 8681. Berg, S
    et al.
    Delude, RL
    Linkoping Univ, S-58183 Linkoping, Sweden Univ Pittsburgh, Dept Crit Care Med, Pittsburgh, PA 15260 USA Dept Pathol, Pittsburgh, PA USA Dept Crit Care Med, Pittsburgh, PA USA.
    Fink, MP
    Linkoping Univ, S-58183 Linkoping, Sweden Univ Pittsburgh, Dept Crit Care Med, Pittsburgh, PA 15260 USA Dept Pathol, Pittsburgh, PA USA Dept Crit Care Med, Pittsburgh, PA USA.
    Pro-inflammatory cytokines increase ATP consumption rate in cultured rat enterocytes2001In: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 29, no 12, p. 26-Conference paper (Other academic)
  • 8682.
    Berg, Sandra
    et al.
    Linköping University, Department of Management and Engineering.
    Wannes, Rebecca
    Linköping University, Department of Management and Engineering.
    ROT-avdrag ur ett småföretagarperspektiv: en studie av hur de nya reglerna med fakturamodellen uppfattas2010Student paper other, 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Background and problem discussion: For the purpose of this study, “ROT-avdrag” is translated into Renovation deduction. It is a tax reduction for individuals of up to 50 % of the cost of labour for repair and maintenance, and renovation and expansion costs. This system has been in use at several occasions, undergoing some changes. The new invoice system was introduced 1st of July 2009 which means that the customer deducts the tax at the point of purchase of the service. In other words, the costumer will only pay half the cost of labour to the seller. Consequently, it is now the seller who is required to request the outstanding sum straight from the Tax Office. The new model and its system has been a hot topic of whether it affects societal actors positively or negatively. Small businesses have highlighted several risks and problems with the new rules.

    Aim: The aim of this study is to examine how the invoice system is perceived by small businesses. It also aims to find out how small businesses perceive that the invoice system relates to the Government’s target of reducing the administrative burden on small businesses, and also to see how the invoice system complies with the target of the Renovation deduction, which is to reduce illegal employment and increase demand in the construction sector.

    Method: This essay is based on a qualitative approach in which interviews have been a central part. Of a total of seven completed interviews, five have been made with small businesses in the construction industry. One interview has been conducted with an accounting consultant and one interview with a legal expert from the Tax Office.

    Results: The result indicates that small businesses´ administrative burden has increased substantially since the invoice system was introduced. Furthermore, different industries are differently affected by the system. The Government´s target with the Renovation deduction has been benefited by the invoice system sinces illegal employment has been reduced and demand for services has increased. The introduction of the invoice system, however, could have been better; the study indicates that the information have been inadequate.

  • 8683.
    Berg, Sofia
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Community Robustness Analysis: Theoretical Approaches to Identifying Keystone Structures in Ecological Communities2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Most of the world’s ecosystems suffer from stress caused by human activities such as habitat destruction, fragmentation, overexploitation of species and climate change. These factors affect the reproduction and/or survival of individual species as well as interactions between species in ecological communities. Forthcoming effects of this are altered abundances, direct species loss, and indirect cascading extinctions, with yet largely unknown consequences on community structure and functioning. Today, biodiversity loss is of global concern since human society and welfare depend upon resources and services provided by ecosystems. The importance of considering entire ecological communities as a target for conservation and management has been increasingly recognized due to the interdependencie  of species. Our ability to make predictions of the response of ecological communities to stress and biodiversity loss is in need of a deeper understanding of how structure and dynamical processes contributes to the functioning and stability of a community. In this thesis I use mathematical theory and dynamical models to study the response of community structure and resilience to a variety of disturbances affecting species and species interactions, ranging from small perturbations (Papers I-II) to large perturbations (species extinctions, Papers IIIIV).

    In Paper I we develop Community Sensitivity Analysis (CSA) as an analytical tool to study how a small permanent perturbation to the intrinsic growth rate, or mortality rate, of species is expected to affect i) the resilience (return rate) and ii) the structure (distribution of species equilibrium abundances) of an ecological community. Species interactions are described using Lotka-Volterra predator-prey dynamics. We apply CSA on the pelagic food webs of Lake Vättern and the Baltic Sea, respectively, and find that a change in the mortality rate of large-bodied species has a higher impact on community resilience and structure, compared to a perturbation to small-bodied species. However, analyzing the effect of a proportional change to the growth or mortality rate of species (elasticity analysis) shows that smallbodied species have proportionally larger effects on species equilibrium abundances, but not on resilience. CSA can also be used to study the effect of permanent (absolute or proportional) changes to inter- and intraspecific interaction strengths. For the two pelagic systems used in this study, CSA reveal that changes in the effect of a prey on its consumer tend to affect community structure and resilience significantly more than changes in the effect of a predator on its prey.

    In Paper II we assess the importance of rare species for the structure and resilience of ecological communities. First we show analytically, for a two species predator-prey system, that a change in the intrinsic growth rate of the rare species affect resilience more than a change in the growth rate of the common species. To test the generality of these results we next apply CSA on complex model food webs. In the analysis we distinguish between four trophic groups, each including only species with a similar trophic position, to separate the effect of abundance from the trophic position of species. Using mixed effect models we find support for our analytical predictions. More precisely, we find a strong negative relationship between the importance (sensitivity) of a species and its equilibrium abundance within all consumer groups and a weaker, but significant, relationship for producer species. The results from this study suggest that rare species can act as keystones through their effect on both community resilience and community structure, regardless of its trophic position.

    In Paper III we evaluate the risk of food web collapse caused by different trait-based extinction scenarios. In previous studies, groups of species, e.g. rare species, large-bodied species and top predators, have been identified to be relatively more prone to extinctions and other studies have found that extinctions of such species have comparably small effects on the remaining community. Using mathematical models of species dynamics we study the response of ecological communities to species removal (i.e. the proportion of species needed to be primarily removed to cause a 50% reduction in species richness, R50) when species are sequentially removed from the food web based on eight different traits. We show, contrary to some previous studies of sequential extinction simulations, that communities can be very vulnerable to realistic species loss. We furthermore find that the response of communities seems to depend on whether the extinction sequence follows a bottom-up or top-down direction, making it difficult to identify one particular extinction sequence as the most important/severe sequence.

    Finally, in Paper IV we aim to identify traits of species that can be used to identify keystone species, in terms of causing the highest proportion of secondary extinctions following their loss, in food webs with different degree of disassembly. Moreover, we analyze if the loss of a species that triggers a cascade of many secondary extinctions are the same species being identified as a keystones using Community Sensitivity Analysis. To answer these questions we randomly remove species from a set of 100 model communities. We analyze the relationship between the number of secondary extinctions following the randomly removed species and a range of species traits in communities where i) 75-100% of the initial number of species remain, ii) 50-75% of all species remain, iii) 25-50% of all species remain and iv) only 0-25% of all species remain. We find that the variation in secondary extinctions explained using species traits increases when the degree of food web disassembly and food web connectance are taken into account. The most important trait varies for different degrees of food web disassembly and also depends on whether basal species can go primarily extinct or not. However, due to correlation between most important traits, we conclude that the key status of different traits is rather robust against structural changes in the model food webs. Interestingly, food webs seem to be most sensitive to a random species loss after the loss of more than 25% of all initial species, suggesting that there is a threshold from which secondary extinctions increases. We also conclude that species being identified as keystones, based on the effect of their loss, are to some extent the same species being identified as having the largest effect on community structure and resilience, respectively, following a small perturbation.

    List of papers
    1. Using sensitivity analysis to identify keystone species and keystone links in size-based food webs
    Open this publication in new window or tab >>Using sensitivity analysis to identify keystone species and keystone links in size-based food webs
    2011 (English)In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 120, no 4, p. 510-519Article in journal (Refereed) Published
    Abstract [en]

    Human-induced alterations in the birth and mortality rates of species and in the strength of interactions within and between species can lead to changes in the structure and resilience of ecological communities. Recent research points to the importance of considering the distribution of body sizes of species when exploring the response of communities to such perturbations. Here, we present a new size-based approach for assessing the sensitivity and elasticity of community structure (species equilibrium abundances) and resilience (rate of return to equilibrium) to changes in the intrinsic growth rate of species and in the strengths of species interactions. We apply this approach on two natural systems, the pelagic communities of the Baltic Sea and Lake Vättern, to illustrate how it can be used to identify potential keystone species and keystone links. We find that the keystone status of a species is closely linked to its body size. The analysis also suggests that communities are structurally and dynamically more sensitive to changes in the effects of prey on their consumers than in the effects of consumers on their prey. Moreover, we discuss how community sensitivity analysis can be used to study and compare the fragility of communities with different body size distributions by measuring the mean sensitivity or elasticity over all species or all interaction links in a community. We believe that the community sensitivity analysis developed here holds some promise for identifying species and links that are critical for the structural and dynamic robustness of ecological communities.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-66991 (URN)10.1111/j.1600-0706.2010.18864.x (DOI)000288753800005 ()
    Available from: 2011-03-24 Created: 2011-03-24 Last updated: 2017-12-11
    2. Rare but important: perturbations to uncommon species have disproportionately large impact on ecological communities
    Open this publication in new window or tab >>Rare but important: perturbations to uncommon species have disproportionately large impact on ecological communities
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The majority of species in the ecosystems of the world are rare. Because the contributions to community biomass and productivity of many of these species are small it has been suggested that loss of rare species should have relatively small ecological consequences. However, the extent to which rare species affect the structure and stability of ecosystems is largely unknown. Using a theoretical approach, based on analytical methods, we here   investigate how perturbations to rare as well as common species affect the structure (distribution of equilibrium abundances of species) and resilience (recovery rate) of complex ecological communities. We show that, contrary to expectation, resilience and structure of ecological communities are generally more sensitive to perturbations to rare than to common species. We find the explanation for this to lie in the cause of rarity: rare species tend to interact strongly, on a per capita basis, with other species. Our results suggest that many rare species are likely to fill important ecological roles in ecosystems.

    Keywords
    Community sensitivity analysis, species abundance, species importance, food webs, stability, resilience
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-88048 (URN)
    Available from: 2013-01-29 Created: 2013-01-29 Last updated: 2013-01-29Bibliographically approved
    3. Ecological communities are vulnerable to realistic extinction sequences
    Open this publication in new window or tab >>Ecological communities are vulnerable to realistic extinction sequences
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Loss of species will directly change the structure of ecological communities, which in turn may cause additional species loss (secondary extinctions) due to indirect effects (e.g. loss of resources or altered population dynamics). The vulnerability of food webs to repeated species loss is expected to be affected by food web topology, species interactions and the order in which species go extinct. Species traits such as body size, abundance and connectivity probably determine the vulnerability to extinction of species and, thus, the order in which species go primarily extinct. However, how different sequences of primary extinctions affect the vulnerability of food webs to secondary extinctions, when species abundances are allowed to respond dynamically, is not well understood. So far, only one study has incorporated species dynamics when assessing the effect of different extinction sequences on community structure, and only a limited number of extinction sequences have been evaluated. Here, using complex model food webs and including population dynamics, we analyze the effect of 33 extinction sequences on community structure using R50 (the proportion of primarily removed species needed to cause a 50% reduction in species richness) as a measure of community robustness to secondary extinctions. As expected, we find community structure to be highly vulnerable to removal of primary producers. More surprisingly, removing species based on traits that are strongly linked to the trophic position of species (such as large-bodied species, rare species, species with a high net effect, species with a high trophic position) are found to be as destructive as removing only primary producers. Such top-down oriented removal of species are often considered to correspond to realistic primary extinctions of species, but earlier studies, based on topological approaches, have not found such realistic extinction sequences to have any drastic effect on the remaining community. Thus, our result suggests that ecological communities could be more vulnerable to realistic extinction sequences than previously believed.

    Keywords
    Community structure, extinction sequence, food webs, species loss, community robustness
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-88050 (URN)
    Available from: 2013-01-29 Created: 2013-01-29 Last updated: 2013-01-29Bibliographically approved
    4. Using species traits to predict secondary extinctions during food web disassembly
    Open this publication in new window or tab >>Using species traits to predict secondary extinctions during food web disassembly
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Global change keeps pushing species towards extinction which results in altered structures of ecological communities. Consequently, the loss of certain species can trigger a cascade of secondary extinctions resulting in further degradation of the system. The importance of species for upholding the structure of communities may be linked to the traits of species. However, due to the altered structure of communities following species loss, the importance of species (and species traits) may change as the structure of the food web change. Using a dynamical approach and simulating species loss in complex model communities we analyze the potential importance of 11 species traits. We find that the most important trait varies for different degree of food web collapse and food web connectance. Though, as the most important traits of species usually are correlated we conclude that the importance of species traits is rather robust against structural changes in the communities (especially when only consumer species are targets of primarily extinctions). Interestingly, food webs display a collapse threshold (after the initial loss of approximately 25% of all species) from which secondary extinctions increases. Finally, consider only the loss of consumer species, the effect (number of secondary extinctions) on community structure caused by a large perturbation (species loss) is positively correlated to the response of food webs resulting from a small perturbation to the same species.

    Keywords
    Community structure, extinction sequence, food webs, species loss, community robustness
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-88052 (URN)
    Available from: 2013-01-29 Created: 2013-01-29 Last updated: 2013-01-29Bibliographically approved
  • 8684.
    Berg, Sofia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology . Linköping University, The Institute of Technology.
    Christianou, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology . Linköping University, The Institute of Technology.
    Jonsson, Tomas
    Research centre for Systems Biology, Univ. of Skövde, Sweden.
    Ebenman, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology . Linköping University, The Institute of Technology.
    Using sensitivity analysis to identify keystone species and keystone links in size-based food webs2011In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 120, no 4, p. 510-519Article in journal (Refereed)
    Abstract [en]

    Human-induced alterations in the birth and mortality rates of species and in the strength of interactions within and between species can lead to changes in the structure and resilience of ecological communities. Recent research points to the importance of considering the distribution of body sizes of species when exploring the response of communities to such perturbations. Here, we present a new size-based approach for assessing the sensitivity and elasticity of community structure (species equilibrium abundances) and resilience (rate of return to equilibrium) to changes in the intrinsic growth rate of species and in the strengths of species interactions. We apply this approach on two natural systems, the pelagic communities of the Baltic Sea and Lake Vättern, to illustrate how it can be used to identify potential keystone species and keystone links. We find that the keystone status of a species is closely linked to its body size. The analysis also suggests that communities are structurally and dynamically more sensitive to changes in the effects of prey on their consumers than in the effects of consumers on their prey. Moreover, we discuss how community sensitivity analysis can be used to study and compare the fragility of communities with different body size distributions by measuring the mean sensitivity or elasticity over all species or all interaction links in a community. We believe that the community sensitivity analysis developed here holds some promise for identifying species and links that are critical for the structural and dynamic robustness of ecological communities.

  • 8685.
    Berg, Sofia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Jonsson, Tomas
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Hauzy, Céline
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Säterberg, Torbjörn
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Christianou, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Yearsley, Jon
    School of Biology and Environmental Science, University College Dublin, Ireland.
    Ebenman, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Rare but important: perturbations to uncommon species have disproportionately large impact on ecological communitiesManuscript (preprint) (Other academic)
    Abstract [en]

    The majority of species in the ecosystems of the world are rare. Because the contributions to community biomass and productivity of many of these species are small it has been suggested that loss of rare species should have relatively small ecological consequences. However, the extent to which rare species affect the structure and stability of ecosystems is largely unknown. Using a theoretical approach, based on analytical methods, we here   investigate how perturbations to rare as well as common species affect the structure (distribution of equilibrium abundances of species) and resilience (recovery rate) of complex ecological communities. We show that, contrary to expectation, resilience and structure of ecological communities are generally more sensitive to perturbations to rare than to common species. We find the explanation for this to lie in the cause of rarity: rare species tend to interact strongly, on a per capita basis, with other species. Our results suggest that many rare species are likely to fill important ecological roles in ecosystems.

  • 8686.
    Berg, Sofia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Pimenov, Alexander
    Weierstrass Institute, Berlin, Germany.
    Palmer, Catherine
    Environmental Research Institute, University College Cork, Cork, Ireland.
    Emmerson, Mark
    Environmental Research Institute, University College Cork, Cork, Ireland.
    Jonsson, Tomas
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Ecological communities are vulnerable to realistic extinction sequencesManuscript (preprint) (Other academic)
    Abstract [en]

    Loss of species will directly change the structure of ecological communities, which in turn may cause additional species loss (secondary extinctions) due to indirect effects (e.g. loss of resources or altered population dynamics). The vulnerability of food webs to repeated species loss is expected to be affected by food web topology, species interactions and the order in which species go extinct. Species traits such as body size, abundance and connectivity probably determine the vulnerability to extinction of species and, thus, the order in which species go primarily extinct. However, how different sequences of primary extinctions affect the vulnerability of food webs to secondary extinctions, when species abundances are allowed to respond dynamically, is not well understood. So far, only one study has incorporated species dynamics when assessing the effect of different extinction sequences on community structure, and only a limited number of extinction sequences have been evaluated. Here, using complex model food webs and including population dynamics, we analyze the effect of 33 extinction sequences on community structure using R50 (the proportion of primarily removed species needed to cause a 50% reduction in species richness) as a measure of community robustness to secondary extinctions. As expected, we find community structure to be highly vulnerable to removal of primary producers. More surprisingly, removing species based on traits that are strongly linked to the trophic position of species (such as large-bodied species, rare species, species with a high net effect, species with a high trophic position) are found to be as destructive as removing only primary producers. Such top-down oriented removal of species are often considered to correspond to realistic primary extinctions of species, but earlier studies, based on topological approaches, have not found such realistic extinction sequences to have any drastic effect on the remaining community. Thus, our result suggests that ecological communities could be more vulnerable to realistic extinction sequences than previously believed.

  • 8687.
    Berg, Sofia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology. University of Skovde, Sweden.
    Pimenov, Alexander
    Weierstrass Institute, Germany; National University of Ireland University of Coll Cork, Ireland.
    Palmer, Catherine
    Weierstrass Institute, Germany.
    Emmerson, Mark
    Queens University of Belfast, North Ireland.
    Jonsson, Tomas
    University of Skovde, Sweden; Swedish University of Agriculture Science, Sweden.
    Ecological communities are vulnerable to realistic extinction sequences2015In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 124, no 4, p. 486-496Article in journal (Refereed)
    Abstract [en]

    Loss of species will directly change the structure and potentially the dynamics of ecological communities, which in turn may lead to additional species loss (secondary extinctions) due to direct and/or indirect effects (e.g. loss of resources or altered population dynamics). Furthermore, the vulnerability of food webs to repeated species loss is expected to be affected by food web topology, species interactions, as well as the order in which species go extinct. Species traits such as body size, abundance and connectivity might determine a species vulnerability to extinction and, thus, the order in which species go primarily extinct. Yet, the sequence of primary extinctions, and their effects on the vulnerability of food webs to secondary extinctions, when species abundances are allowed to respond dynamically, has only recently become the focus of attention. Here, we analyse and compare topological and dynamical robustness to secondary extinctions of model food webs, in the face of 34 extinction sequences based on species traits. Although secondary extinctions are frequent in the dynamical approach and rare in the topological approach, topological and dynamical robustness tends to be correlated for many bottom-up directed, but not for top-down directed deletion sequences. Furthermore, removing species based on traits that are strongly positively correlated to the trophic position of species (such as large body size, low abundance, high net effect) is, under the dynamical approach, found to be as destructive as removing primary producers. Such top-down oriented removal of species are often considered to correspond to realistic extinction scenarios, but earlier studies, based on topological approaches, have found such extinction sequences to have only moderate effects on the remaining community. Thus, our result suggests that the structure of ecological communities, and therefore the integrity of important ecosystem processes could be more vulnerable to realistic extinction sequences than previously believed.

  • 8688.
    Berg, Sofia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Pimenov, Alexander
    Weierstrass Institute, Berlin, Germany.
    Palmer, Catherine
    Environmental Research Institute, University College Cork, Cork, Ireland.
    Emmerson, Mark
    Environmental Research Institute, University College Cork, Cork, Ireland.
    Jonsson, Tomas
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Using species traits to predict secondary extinctions during food web disassemblyManuscript (preprint) (Other academic)
    Abstract [en]

    Global change keeps pushing species towards extinction which results in altered structures of ecological communities. Consequently, the loss of certain species can trigger a cascade of secondary extinctions resulting in further degradation of the system. The importance of species for upholding the structure of communities may be linked to the traits of species. However, due to the altered structure of communities following species loss, the importance of species (and species traits) may change as the structure of the food web change. Using a dynamical approach and simulating species loss in complex model communities we analyze the potential importance of 11 species traits. We find that the most important trait varies for different degree of food web collapse and food web connectance. Though, as the most important traits of species usually are correlated we conclude that the importance of species traits is rather robust against structural changes in the communities (especially when only consumer species are targets of primarily extinctions). Interestingly, food webs display a collapse threshold (after the initial loss of approximately 25% of all species) from which secondary extinctions increases. Finally, consider only the loss of consumer species, the effect (number of secondary extinctions) on community structure caused by a large perturbation (species loss) is positively correlated to the response of food webs resulting from a small perturbation to the same species.

  • 8689.
    Berg, Svante
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Linköping University, Faculty of Health Sciences.
    On Total Disc Replacement2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Low back pain consumes a large part of the community’s resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient’s quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR).

    This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR.

    The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%).

    Time of surgery and total time in hospital were shorter in the TDR group.

    There was no difference in complications and reoperations, except that seventeen of the patients in the fusion group were re-operated for removal of their implants.

    The second study concerned sex life and sexual function. TDR is performed via an anterior approach, an approach that has been used for a long time for various procedures on the lumbar spine. A frequent complication reported in males when this approach is used is persistent retrograde ejaculation. The TDR group in this material was operated via an extra-peritoneal approach to the retroperitoneal space, and there were no cases of persistent retrograde ejaculation. There was a surprisingly high frequency of men in the fusion group reporting deterioration in ability to have an orgasm postoperatively.

    Preoperative sex life was severely hampered in the majority of patients in the entire material, but sex life underwent a marked improvement in both treatment groups by the two-year follow-up that correlated with reduction in back pain.

    The third study was on mobility in the lumbar spinal segments, where X-rays were taken in full extension and flexion prior to surgery and at two-year follow-up. Analysis of the films showed that 78% of the patients in the fusion group reached the surgical goal (non-mobility) and that 89% of the TDR patients maintained mobility.

    Preoperative disc height was lower than in a normative database in both groups, and remained lower in the fusion group, while it became higher in the TDR group. Mobility in the operated segment increased in the TDR group postoperatively. Mobility at the rest of the lumbar spine increased in both treatment groups. Mobility in adjacent segments was within the norm postoperatively, but slightly larger in the fusion group.

    In the fourth study the health economics of TDR vs Fusion was analysed. The hospital costs for the procedure were higher for patients in the fusion group compared to the TDR group, and the TDR patients were on sick-leave two months less.

    In all, these studies showed that the results in the TDR group were as good as in the fusion group. Patients are more likely to be totally pain-free when treated with TDR compared to fusion. Treatment with this new procedure seems justified in selected patients at least in the short-term perspective. Long-term follow-up is underway and results will be published in due course.

    List of papers
    1. Total disc replacement compared to lumbar fusion: a randomised controlled trial with 2-year follow-up
    Open this publication in new window or tab >>Total disc replacement compared to lumbar fusion: a randomised controlled trial with 2-year follow-up
    Show others...
    2009 (English)In: EUROPEAN SPINE JOURNAL, ISSN 0940-6719, Vol. 18, no 10, p. 1512-1519Article in journal (Refereed) Published
    Abstract [en]

    The study design includes a prospective, randomised controlled study comparing total disc replacement (TDR) with posterior fusion. The main objective of this study is to compare TDR with lumbar spinal fusion, in terms of clinical outcome, in patients referred to a spine clinic for surgical evaluation. Fusion is effective for treating chronic low back pain (LBP), but has drawbacks, such as stiffness and possibly adjacent level degradation. Motion-preserving options have emerged, of which TDR is frequently used because of these drawbacks. How the results of TDR compare to fusion, however, is uncertain. One hundred and fifty-two patients with a mean age of 40 years (21-55) were included: 90 were women, and 80 underwent TDR. The patients had not responded to a conservative treatment programme and suffered from predominantly LBP, with varying degrees of leg pain. Diagnosis was based on clinical examination, radiographs, MRI, and in unclear cases, diagnostic injections. Outcome measures were global assessment (GA), VAS for back and leg pain, Oswestry Disability Index, SF36 and EQ5D at 1 and 2 years. Follow-up rate was 100%, at both 1 and 2 years. All outcome variables improved in both groups between preoperative and follow-up assessment. The primary outcome measure, GA, revealed that 30% in the TDR group and 15% in the fusion group were totally pain-free at 2 years (P = 0.031). TDR patients had reached maximum recovery in virtually all variables at 1 year, with significant differences compared to the fusion group. The fusion patients continued to improve and at 2 years had results similar to TDR patients apart from numbers of pain-free. Complications and reoperations were similar in both groups, but pedicle screw removal as additive surgery, was frequent in the fusion group. One year after surgery, TDR was superior to spinal fusion in clinical outcome, but this difference had diminished by 2 years, apart from (VAS for back pain and) numbers of pain-free. The long-term benefits have yet to be examined.

    Keywords
    Degenerative disc disease, Prospective randomised controlled trial, Total disc replacement, Spinal fusion, Patients global assessment of back pain
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-51285 (URN)10.1007/s00586-009-1047-0 (DOI)
    Available from: 2009-10-26 Created: 2009-10-26 Last updated: 2010-03-08
    2. Sex life and sexual function in men and women before and after total disc replacement compared with posterior lumbar fusion
    Open this publication in new window or tab >>Sex life and sexual function in men and women before and after total disc replacement compared with posterior lumbar fusion
    2009 (English)In: The spine journal, ISSN 1529-9430, E-ISSN 1878-1632, Vol. 9, no 12, p. 987-994Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND CONTEXT: Sex life and sexual function maybe affected by low back pain (LBP). Sexual dysfunction after anterior lumbar fusion is reported in both men and women, but focus is mainly on impaired male biological function (retrograde ejaculation) as this may cause infertility. This has led to concern as to whether anterior surgery should be employed in men, at least in younger age groups. PURPOSE: To investigate how chronic low back pain (CLBP) of assumed discogenic origin affects sex life and sexual function in patients considered for surgical treatment, whether this is affected by surgical treatment (total disc replacement [TDR] or posterolateral fusion [PLF]/posterior lumbar interbody fusion [PLIF]), and if so, are there differences between the surgical procedures undertaken. STUDY DESIGN: A randomized controlled trial comparing TDR and instrumented lumbar spine fusion, performed either as a PLF or PLIF. PATIENT SAMPLE: One hundred fifty-two patients were included in this randomized controlled trial to compare the effect on CLBP of either TDR via an anterior retroperitoneal approach or instrumented posterior lumbar fusion, PLF or PLIF. OUTCOME MEASURES: Global assessment of back pain, back pain (visual analog scale [VAS] 0-100), function (Oswestry Disability Index [ODI] 0-100), quality of life (EQ5D [EuroQol] 0-1), and answers on specific sexual function. METHODS: Outcome was assessed using data from the Swedish Spine Register (SweSpine). In ODI, one question, ODI 8, reflects the impact of back pain on sex life. This question was analyzed separately. Patients also answered a gender-specific questionnaire preoperatively and at the 2-year follow-up to determine any sexual dysfunction regarding erection, orgasm, and ejaculation. Followup was at 1 and 2 years. RESULTS: Before surgery, 34% reported that their sex life caused some extra LBP, and an additional 30% that their sex life was severely restricted by LBP. After surgery, sex life improved in both groups, with a strong correlation to a reduction of LBP. The gender-specific questionnaire used to measure sexual function after 2 years revealed no negative effect of TDR or Fusion in men regarding erection or retrograde ejaculation. However, 26% of all men in the Fusion group, compared with 3% in the TDR group, reported postoperative deterioration in the ability to achieve orgasm, despite a reduction of LBP CONCLUSIONS: Impairment of sex life appears to be related to CLBP. An improvement in sex life after TDR or lumbar fusion was positively correlated to a reduction in LBP. Total disc replacement in this study, performed through an anterior retroperitoneal approach, was not associated with greater sexual dysfunction compared with instrumented lumbar fusion performed either as a PLF or as a PLIF. Sexual function, expressed as orgasm, deteriorated in men in the Fusion group postoperatively, in spite of this group reporting less LBP after 2 years.

    Keywords
    Sex life; Sexual dysfunction; Retrograde ejaculation; Total disc replacement; Lumbar fusion; Low back pain
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-52885 (URN)10.1016/j.spinee.2009.08.454 (DOI)
    Available from: 2010-01-13 Created: 2010-01-12 Last updated: 2017-12-12
    3. Disc height and motion patterns in the lumbar spine in patients treated with total disc replacement or fusion for discogenic back pain: Results from a randomized controlled trial
    Open this publication in new window or tab >>Disc height and motion patterns in the lumbar spine in patients treated with total disc replacement or fusion for discogenic back pain: Results from a randomized controlled trial
    2011 (English)In: The spine journal, ISSN 1529-9430, E-ISSN 1878-1632, Vol. 11, no 11, p. 991-998Article in journal (Refereed) Published
    Abstract [en]

    Study Design. Comparison of X-ray measurements in a randomized controlled trial between instrumented posterior fusion (N=72) and total disc replacement (TDR) (N=80) for chronic low back pain assumed to be discogenic. Results were compared to clinical outcome.

    Objective. To see if surgical goals for respective treatments had been reached, if clinical outcome was related to this, and if differences in disc height and adjacent segment motion patterns between groups occurred.

    Summary of Background Data. Fusion is considered the “gold standard” in surgical treatment of degenerated disc disease, though the resulting stiffness may induce degeneration in adjacent segments. TDR aims to restore and maintain mobility by replacing a painful disc. Little is known about the degree and quality of mobility in artificial discs in vivo, and whether maintained mobility reduces stress on adjacent segments.

    Methods. Flexion-extension X-rays were analyzed pre- and two years postoperatively using Distortion Compensated Roentgen Analysis (DCRA) at treated and adjacent levels, mobility following fusion and TDR was estimated. Changes in disc height and changes in mobility patterns in adjacent segments were compared. The results were compared with clinical outcome regarding back pain.

    Results. 78% of fused patients had no mobility whereas 89% of TDR-patients were mobile, but with less than normal mobility. The fulfilment of surgical goals was not correlated to clinical outcome. Fused segments were lower and TDR-segments were higher than normal. There were minor differences, there being more translation or flexion-extension at adjacent levels in the fusion group than in the TDR group.

    Conclusions. This very accurate X-ray method (DCRA) indicates that surgical goals were reached in most patients. This however, was not correlated to outcome. Differences between the groups in postoperative disc height and motion patterns at adjacent segments may lead to differences in outcome in the long-term perspective, but this was not detectable after two years.

    Place, publisher, year, edition, pages
    Elsevier, 2011
    Keywords
    RCT, Fusion, total disc replacement, mobility, disc height, clinical outcome, DCRA, adjacent segment
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-54288 (URN)10.1016/j.spinee.2011.08.434 (DOI)000297864300001 ()
    Available from: 2010-03-08 Created: 2010-03-08 Last updated: 2017-12-12
    4. Cost effectiveness of disc prosthesis versus lumbar fusion in patients with chronic low back pain: randomized controlled trial with 2-year follow-up:  
    Open this publication in new window or tab >>Cost effectiveness of disc prosthesis versus lumbar fusion in patients with chronic low back pain: randomized controlled trial with 2-year follow-up:  
    Show others...
    2011 (English)In: European spine journal, ISSN 0940-6719, E-ISSN 1432-0932, Vol. 20, no 7, p. 1001-1011Article in journal (Refereed) Published
    Abstract [en]

    When low back pain becomes chronic, surgery is sometimes performed. The gold standard today is lumbar fusion (FUS), using a variety of procedures. Total disc replacement (TDR) aimed at motion preservation is increasing in popularity. This randomized controlled health economic study assesses the cost-effectiveness of TDR (Charité/Prodisc/Maverick) compared with instrumented FUS (posterior lumbar fusion (PLF)/posterior lumbar interbody fusion (PLIF). Social and healthcare perspectives after two years are reported. In all, 152 patients were randomized to either TDR (n=80) or FUS (n=72). Cost to society, (total mean cost/patient, Swedish kronor=SEK, standard deviation) for TDR was SEK 599,560 (400,272), and for FUS SEK 685,919 (422,903) (ns). TDR was significantly less costly from a healthcare perspective, SEK 22,996 (43,055- -1,202). Number of days on sick leave among those who returned to work was 185 (146) in the TDR group, and 252 (189) in the FUS group (ns). Using EQ-5D, the total gain in quality adjusted life years (QALYs) over two years was 0.41 units for TDR and 0.40 units for FUS (ns). Based on EQ-5D, the incremental cost effectiveness ratio (ICER) of using TDR instead of FUS was difficult to analyze due to the “non-difference” in treatment outcome, which is why cost/QALY could not be defined. Using cost-effectiveness probabilistic analysis, the net benefit with CI) was found to be SEK 91,359 (-73,643 – 249,114) (ns).

    Conclusion: It is not possible to state whether TDR or FUS is more cost-effective after two years. Since disc replacement and lumbar fusion are based on different conceptual approaches, it is important to follow these results over time.

    Place, publisher, year, edition, pages
    Springer, 2011
    Keywords
    Disc prosthesis; Lumbar fusion; Cost-effectiveness; Cost-utility; Health economic evaluation
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-54289 (URN)10.1007/s00586-010-1607-3 (DOI)000292746500002 ()
    Available from: 2010-03-08 Created: 2010-03-08 Last updated: 2017-12-12
  • 8690.
    Berg, Svante
    et al.
    Lowenstromska Hosp, Stockholm Spine Ctr, SE-19489 Stockholm, Sweden.
    Fritzell, Peter
    Falun Cent Hosp, Dept Orthoped Surg, S-79182 Falun, Sweden.
    Tropp, Hans
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Sex life and sexual function in men and women before and after total disc replacement compared with posterior lumbar fusion2009In: The spine journal, ISSN 1529-9430, E-ISSN 1878-1632, Vol. 9, no 12, p. 987-994Article in journal (Refereed)
    Abstract [en]

    BACKGROUND CONTEXT: Sex life and sexual function maybe affected by low back pain (LBP). Sexual dysfunction after anterior lumbar fusion is reported in both men and women, but focus is mainly on impaired male biological function (retrograde ejaculation) as this may cause infertility. This has led to concern as to whether anterior surgery should be employed in men, at least in younger age groups. PURPOSE: To investigate how chronic low back pain (CLBP) of assumed discogenic origin affects sex life and sexual function in patients considered for surgical treatment, whether this is affected by surgical treatment (total disc replacement [TDR] or posterolateral fusion [PLF]/posterior lumbar interbody fusion [PLIF]), and if so, are there differences between the surgical procedures undertaken. STUDY DESIGN: A randomized controlled trial comparing TDR and instrumented lumbar spine fusion, performed either as a PLF or PLIF. PATIENT SAMPLE: One hundred fifty-two patients were included in this randomized controlled trial to compare the effect on CLBP of either TDR via an anterior retroperitoneal approach or instrumented posterior lumbar fusion, PLF or PLIF. OUTCOME MEASURES: Global assessment of back pain, back pain (visual analog scale [VAS] 0-100), function (Oswestry Disability Index [ODI] 0-100), quality of life (EQ5D [EuroQol] 0-1), and answers on specific sexual function. METHODS: Outcome was assessed using data from the Swedish Spine Register (SweSpine). In ODI, one question, ODI 8, reflects the impact of back pain on sex life. This question was analyzed separately. Patients also answered a gender-specific questionnaire preoperatively and at the 2-year follow-up to determine any sexual dysfunction regarding erection, orgasm, and ejaculation. Followup was at 1 and 2 years. RESULTS: Before surgery, 34% reported that their sex life caused some extra LBP, and an additional 30% that their sex life was severely restricted by LBP. After surgery, sex life improved in both groups, with a strong correlation to a reduction of LBP. The gender-specific questionnaire used to measure sexual function after 2 years revealed no negative effect of TDR or Fusion in men regarding erection or retrograde ejaculation. However, 26% of all men in the Fusion group, compared with 3% in the TDR group, reported postoperative deterioration in the ability to achieve orgasm, despite a reduction of LBP CONCLUSIONS: Impairment of sex life appears to be related to CLBP. An improvement in sex life after TDR or lumbar fusion was positively correlated to a reduction in LBP. Total disc replacement in this study, performed through an anterior retroperitoneal approach, was not associated with greater sexual dysfunction compared with instrumented lumbar fusion performed either as a PLF or as a PLIF. Sexual function, expressed as orgasm, deteriorated in men in the Fusion group postoperatively, in spite of this group reporting less LBP after 2 years.

  • 8691.
    Berg, Svante
    et al.
    Lowenstromska Hospital.
    Tropp, Hans
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Leivseth, Gunnar
    Institute Of Clinical Neuroscience,Norwegian University of Science and Technology, Trondheim, Norway.
    Disc height and motion patterns in the lumbar spine in patients treated with total disc replacement or fusion for discogenic back pain: Results from a randomized controlled trial2011In: The spine journal, ISSN 1529-9430, E-ISSN 1878-1632, Vol. 11, no 11, p. 991-998Article in journal (Refereed)
    Abstract [en]

    Study Design. Comparison of X-ray measurements in a randomized controlled trial between instrumented posterior fusion (N=72) and total disc replacement (TDR) (N=80) for chronic low back pain assumed to be discogenic. Results were compared to clinical outcome.

    Objective. To see if surgical goals for respective treatments had been reached, if clinical outcome was related to this, and if differences in disc height and adjacent segment motion patterns between groups occurred.

    Summary of Background Data. Fusion is considered the “gold standard” in surgical treatment of degenerated disc disease, though the resulting stiffness may induce degeneration in adjacent segments. TDR aims to restore and maintain mobility by replacing a painful disc. Little is known about the degree and quality of mobility in artificial discs in vivo, and whether maintained mobility reduces stress on adjacent segments.

    Methods. Flexion-extension X-rays were analyzed pre- and two years postoperatively using Distortion Compensated Roentgen Analysis (DCRA) at treated and adjacent levels, mobility following fusion and TDR was estimated. Changes in disc height and changes in mobility patterns in adjacent segments were compared. The results were compared with clinical outcome regarding back pain.

    Results. 78% of fused patients had no mobility whereas 89% of TDR-patients were mobile, but with less than normal mobility. The fulfilment of surgical goals was not correlated to clinical outcome. Fused segments were lower and TDR-segments were higher than normal. There were minor differences, there being more translation or flexion-extension at adjacent levels in the fusion group than in the TDR group.

    Conclusions. This very accurate X-ray method (DCRA) indicates that surgical goals were reached in most patients. This however, was not correlated to outcome. Differences between the groups in postoperative disc height and motion patterns at adjacent segments may lead to differences in outcome in the long-term perspective, but this was not detectable after two years.

  • 8692.
    Berg, Svante
    et al.
    Lowenstromska Hospital.
    Tullberg, Tycho
    Lowenstromska Hospital.
    Branth, Bjoern
    Lowenstromska Hospital.
    Olerud, Claes
    Lowenstromska Hospital.
    Tropp, Hans
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Total disc replacement compared to lumbar fusion: a randomised controlled trial with 2-year follow-up2009In: EUROPEAN SPINE JOURNAL, ISSN 0940-6719, Vol. 18, no 10, p. 1512-1519Article in journal (Refereed)
    Abstract [en]

    The study design includes a prospective, randomised controlled study comparing total disc replacement (TDR) with posterior fusion. The main objective of this study is to compare TDR with lumbar spinal fusion, in terms of clinical outcome, in patients referred to a spine clinic for surgical evaluation. Fusion is effective for treating chronic low back pain (LBP), but has drawbacks, such as stiffness and possibly adjacent level degradation. Motion-preserving options have emerged, of which TDR is frequently used because of these drawbacks. How the results of TDR compare to fusion, however, is uncertain. One hundred and fifty-two patients with a mean age of 40 years (21-55) were included: 90 were women, and 80 underwent TDR. The patients had not responded to a conservative treatment programme and suffered from predominantly LBP, with varying degrees of leg pain. Diagnosis was based on clinical examination, radiographs, MRI, and in unclear cases, diagnostic injections. Outcome measures were global assessment (GA), VAS for back and leg pain, Oswestry Disability Index, SF36 and EQ5D at 1 and 2 years. Follow-up rate was 100%, at both 1 and 2 years. All outcome variables improved in both groups between preoperative and follow-up assessment. The primary outcome measure, GA, revealed that 30% in the TDR group and 15% in the fusion group were totally pain-free at 2 years (P = 0.031). TDR patients had reached maximum recovery in virtually all variables at 1 year, with significant differences compared to the fusion group. The fusion patients continued to improve and at 2 years had results similar to TDR patients apart from numbers of pain-free. Complications and reoperations were similar in both groups, but pedicle screw removal as additive surgery, was frequent in the fusion group. One year after surgery, TDR was superior to spinal fusion in clinical outcome, but this difference had diminished by 2 years, apart from (VAS for back pain and) numbers of pain-free. The long-term benefits have yet to be examined.

  • 8693.
    Berg, Sören
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Akut handläggning av svår sepsis och septisk chock2013In: Sepsis på akuten & IVA: diagnostik och antibiotikaterapi / [ed] Håkan Hanberger, Linköping: Linköpings universitet , 2013, 2, p. 14-25Chapter in book (Other academic)
  • 8694.
    Berg, Sören
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Faculty of Health Sciences.
    Hyaluronan in sepsis: A clinical and experimental study1994Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Sepsis and septic shock are important causes of morbidity and mortality in the intensive care unit (ICU). Mortality rates in septic shock are estimated to be 40-50%, in spite of modem intensive care. Death is commonly caused by cardiovascular collapse and multiple organ dysfunction syndrome (MODS). Hepatic dysfunction is a common component of MODS, and can have a major impact on prognosis and survival. Sepsis is, among other derangements, also accompanied by disturbed tissue water homeostasis with increased extravasation of water resulting in tissue edema.

    Hyaluronan is an interstitial macromolecule that participates in the regulation of tissue hydration. It is normally present in small concentrations in the blood, and is rapidly cleared from the blood by the liver endothelial cells. The synthesis of hyaluronan can be stimulated by inflammatory mediators. Thus sepsis and hyaluronan turnover could interact in many ways. The aim of the present investigations was to study possible changes in circulating hyaluronan concentrations in relation to sepsis and septic shock.

    Plasma levels of hyaluronan were studied in 44 patients with infections and septic shock. Increased plasma concentrations were found, and the increase correlated to disease severity and outcome. In experimentally induced sepsis in pigs, an increase in circulating concentrations was found, and a relation to hemodynamic instability and outcome was seen. A moderate increase in blood hyaluronan concentrations was seen after surgical trauma in both humans and pigs. Crystalloid infusion therapy also caused a small increase in plasma hyaluronan concentrations in healthy volunteers, probably through an increased washout of interstitial hyaluronan. The hepatic turnover of hyaluronan was studied in septic shock patients. Low extraction ratios at high circulating concentrations were found, suggesting a reduced capacity of hepatic uptake and an increased inflow to the circulation. The kinetics of plasma turnover of hyaluronan were studied in septic and non-septic ICU patients. A prolonged half-life was seen among the septic patients, suggesting a reduced clearance capacity.

    In conclusion, sepsis is accompanied by increased circulating hyaluronan concentrations. The magnitude of the increase seems to correlate to disease severity and outcome. The cause of this increase is suggested to be both reduced hepatic uptake function, and increased input to the circulation. The relative contributions of these mechanisms, and the possible clinical utility of plasma hyaluronan measurements, remain to be determined.

  • 8695.
    Berg, Sören
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Delude, RL
    Fink, MP
    Increased glycolysis maintains ATP levels after hypoxia and cytokine stimulation in rat enterocytes2002In: Intensive Care Medicine, ISSN 0342-4642, E-ISSN 1432-1238, Vol. 28, p. 236-Conference paper (Other academic)
  • 8696.
    Berg, Sören
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Engman, A
    Stockholm.
    Holmgren, Susanna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Lundahl, T
    Västervik.
    Laurent, T
    Uppsala.
    Increased plasma hyaluronan in severe pre-eclampsia and eclampsia2001In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 61, no 2, p. 131-138Article in journal (Refereed)
    Abstract [en]

    Pre-eclampsia is a serious multi-system disorder with general endothelial disease, often with a component of hepatic dysfunction. The pathogenesis of pre-eclampsia is not fully understood, and no specific diagnostic tests are available for early and reliable diagnosis, or for monitoring of the disease process. Hyaluronan is an extracellular matrix polysaccharide present at low concentrations in plasma. Normally, it is rapidly eliminated from the blood by the liver. Increased concentrations of circulating hyaluronan are seen in conditions with impaired hepatic function such as liver cirrhosis, and hyaluronan concentrations have previously been used to evaluate hepatic function in other diseases. In the present study, 11 pregnant women admitted to the intensive care unit with severe pre-eclampsia or eclampsia were studied. As control 31 healthy pregnant women, 18 undergoing vaginal delivery and 13 caesarean section, were included. Plasma hyaluronan was measured before and after delivery. Increased concentrations of plasma hyaluronan were found in the pre-eclampsia group both before (171 (75-586) ╡g/L (p < 0.01) and after delivery (215 (124-768) ╡g/L (p < 0.001) (median and inter-quartile range), as compared to both caesarean section (13 (7-28) ╡g/L before and 28 (18-48) ╡g/L after delivery) and vaginal delivery healthy controls (12 (8-24) ╡g/L before and 30 (13-63) ╡g/L after delivery). In the control groups, a small increase in plasma hyaluronan was seen after delivery, after both caesarean section (p < 0.05) and vaginal delivery (p < 0.01). In conclusion, plasma hyaluronan is increased in severe pre-eclampsia and eclampsia. The cause of the increase is unknown.

  • 8697.
    Berg, Sören
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Fink, MP
    Linkoping Univ, S-58183 Linkoping, Sweden Univ Pittsburgh, Dept Surg, Pittsburgh, PA USA Univ Pittsburgh, Dept Crit Care Med, Pittsburgh, PA USA.
    Delude, RL
    Linkoping Univ, S-58183 Linkoping, Sweden Univ Pittsburgh, Dept Surg, Pittsburgh, PA USA Univ Pittsburgh, Dept Crit Care Med, Pittsburgh, PA USA.
    Cytokine exposure prior to hypoxia modulates HIF-1 nuclear binding in response to hypoxia in cultured rat (IEC-6) enterocytes2001In: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 29, no 12, p. 77-Conference paper (Other academic)
  • 8698.
    Berg, Sören
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Golster, M
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, MKC - Medicin och kirurgicentrum, Anestesi.
    Lisander, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, MKC - Medicin och kirurgicentrum, Anestesi.
    Albumin extravasation and tissue washout of hyaluronan after plasma volume expansion with crystalloid or hypooncotic colloid solutions2002In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 46, no 2, p. 166-172Article in journal (Refereed)
    Abstract [en]

    Background: Intravascular volume expansion is followed by loss of fluid from the circulation. The extravasation of albumin in this readjustment is insufficiently known. Methods: Twelve male volunteers participated, each in three separate sessions, in a controlled, randomised, open fashion. They received one of the following: albumin 40g/L,(7.1mL/kg, i.e. 500mL per 70kg), Ringer's acetate (21.4mL/kg), or dextran 30g/L (7.1mL/kg). The fluids were infused during 30min and the subjects were followed for 180min. ECG, arterial oxygen saturation and non-invasive arterial pressure were recorded. Haemoglobin, haematocrit, serum albumin and osmolality, plasma colloid osmotic pressure and hyaluronan concentration were determined in venous samples. Results: The serum albumin concentration decreased (P < 0.05, ANOVA) following Ringer's acetate or dextran, whereas serum osmolality was unchanged in all groups. The colloid osmotic pressure decreased (P<0.05) after the Ringer solution. The blood volume increase was estimated from the decrease in haemoglobin concentration and did not differ between the three fluids. The cumulated extravasation of albumin was largest following albumin (10.4 ▒ 5.4g, mean ▒ SD), less following dextran (5.6 ▒ 5.0 g) and negligible in the Ringer group (0.5 ▒ 10.0 g, P < 0.05 against albumin). However, the Ringer solution increased the plasma concentration of hyaluronan drastically. Conclusions: Infusion of hypotonic colloidal solutions entails net loss of albumin from the vascular space. This is not the case after Ringer's acetate. Increased interstitial hydration from the latter fluid is followed by lymphatic wash out of hyaluronan. ⌐ Acta Anaesthesiologica Scandinavica.

  • 8699.
    Berg, Sören
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Sappington, P.L.
    Department of Critical Care Medicine, Univ. of Pittsburgh Sch. of Medicine, Pittsburgh, PA, United States.
    Guzik, L.J.
    Department of Critical Care Medicine, Univ. of Pittsburgh Sch. of Medicine, Pittsburgh, PA, United States.
    Delude, R.L.
    Department of Critical Care Medicine, Univ. of Pittsburgh Sch. of Medicine, Pittsburgh, PA, United States, Department of Pathology, Univ. of Pittsburgh Sch. of Medicine, Pittsburgh, PA, United States.
    Fink, M.P.
    Department of Critical Care Medicine, Univ. of Pittsburgh Sch. of Medicine, Pittsburgh, PA, United States, Department of Surgery, Univ. of Pittsburgh Sch. of Medicine, Pittsburgh, PA, United States, 616 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA 15261, United States.
    Proinflammatory cytokines increase the rate of glycolysis and adenosine-5'-triphosphate turnover in cultured rat enterocytes2003In: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 31, no 4, p. 1203-1212Article in journal (Refereed)
    Abstract [en]

    Objective: Measurements of steady-state adenosine-5'-triphosphate (ATP) levels in tissue samples from patients or experimental animals with sepsis or endotoxemia provide little information about the rate of ATP production and consumption in these conditions. Accordingly, we sought to use an in vitro "reductionist" model of sepsis to test the hypothesis that proinflammatory cytokines modulate ATP turnover rate. Design: In vitro "reductionist" model of sepsis. Setting: University laboratory. Subjects: Cultured rat enterocyte-like cells. Interventions: IEC-6 nontransformed rat enterocytes were studied under control conditions or following incubation for 24 or 48 hrs with cytomix, a mixture of tumor necrosis factor-a (10 ng/mL), interleukin-1ß (1 ng/mL), and interferon-? (1000 units/mL). To measure ATP turnover rate, ATP synthesis was acutely blocked by adding to the cells a mixture of 2-deoxyglucose (10 mM), potassium cyanide (8 mM), and antimycin A (1 µM). ATP content was measured at baseline (before metabolic inhibition) and 0.5, 1, 2, 5, and 10 mins later. Log-linear ATP decay curves were generated and the kinetics of ATP utilization thereby calculated. Measurements and Main Results: ATP consumption rate was higher in cytomix-stimulated compared with control cells (3.11 ± 1.39 vs. 1.25 ± 0.66 nmol/min, respectively, p < .01). Similarly, the half-time for ATP disappearance was shorter in cytomix-stimulated compared with control cells (2.63 ± 1.00 vs. 6.21 ± 3.49, p < .05). In contrast to these findings, the rate of ATP disappearance was similar in cytokine-naïve and immunostimulated IEC-6 cells when protein and nucleic acid synthesis were inhibited by adding 50 µg/mL cycloheximide and 5 µg/mL actinomycin D to cultures for 4 hrs. The rates of glucose consumption and lactate production were significantly greater in cytomix-stimulated compared with controls cells. Conclusions: Incubation of IEC-6 cells with cytomix significantly increased ATP turnover. Increased ATP turnover rate was supported by increases in the rate of anaerobic glycolysis. These findings support the view that proinflammatory mediators impose a metabolic demand on visceral cells. In sepsis, cells may be more susceptible to dysfunction on the basis of diminished oxygen delivery and/or mitochondrial dysfunction.

  • 8700.
    Berg, Thirése
    Linköping University, Department of Social and Welfare Studies.
    Medias framväxt – individens bakslag?: En studie kring tjejers uppfattningar och upplevelser av Internetmobbning2011Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Jag har undersökt hur ca ett 30 tal tjejer uppfattar och upplevt Internetmobbning. Jag har bland annat studerat vad Internetmobbningen har för definition hos informanterna, varför Internetmobbning uppstår, om det, enligt informanterna är lika allvarligt som vanlig mobbning, som bland annat sker i skolor och på arbetsplatser, om Internetmobbning kan tänkas vara mer accepterat i samhället, huruvida informanterna har upplevt och påverkats av Internetmobbningen, och om de tror att det skiljer sig lika mycket Internetmobbning bland könen eller om det kan tänkas skilja sig. Mina teoretiska utgångspunkter härstammar från social psykologin och innefattar bland annat sociala identitetsprocesser, social interaktion och socialt identitetsskapande. Jag har även, utöver teori använt mig av tidigare forskning kring Internetmobbning men också av perspektiv tjejmobbning. Materialet är inhämtat från en enkätundersökning och har kodats och analyserats med hjälp av Grundad Teori. Studien avlutas med en slutdiskussion där jag sammanför mitt analysmaterial med informanternas utsagor och för dessa samman med mina teorietiska utgångspunkter. Studien redovisar bland annat för att informanternas upplevelser av Internetmobbning har, enligt dem, både omformat och utvecklat sina identiteter på olika sätt. Denna studie ämnar till att uppmärksamma Internetmobbning, både för samhällsforskningen men också för enskilda individer i samhället och för att, genom studien, redovisa eventuella effekter av detta fenomen.

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