| 1. |
- Isaksson, Joakim, 1976-
(författare)
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Spänningen mellan normalitet och avvikelse : om skolans insatser för elever i behov av särskilt stöd
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden, an increasing number of pupils are defined as having some form of difficulties in school. In order to receive special support measures in school, these difficulties must have been subject to a pedagogical examination that state that the pupil is in need of special support measures. This work of identifying and defining difficulties implies that questions about normality and deviance inevitably come into play in school. There has been an increasing demand in school politics to identify these difficulties as early as possible, and this demand has placed further pressure on school personnel in this issue. Furthermore, the personnel’s perspective on the difficulties is also important, i.e., in terms of their origin, because this has importance for the design and content of the special support measures. The overall aim of this thesis is to analyse the tension between normality and deviance that is manifested in the school’s work procedures for pupils with special educational needs. Related to the overall aim, four overarching research questions are addressed. How have pupils with special educational needs and special education been articulated in national policy documents during recent decades? What perspective on school difficulties are being portrayed in schools’ individual educational plans for pupils with special educational needs? How do school personnel identify and differentiate pupils with special educational needs from “normal” pupils? How do pupils with special educational needs and their parents experience the special support measures that they receive in school and what seems to be the main concern of such support measures? The thesis consists of four studies that are based on different empirical materials such as policy documents, individual educational plans (IEPs) and qualitative interviews with school personnel, pupils and parents. The methods that are used for analysing the material are policy analysis, content analysis and grounded theory. The results show that the target group for special support measures has been ascribed with different meanings (over time) in policy documents, something that has affected the recommendations of the support measures and the choice of actors who are assigned to provide such support. Furthermore, the IEPs, as well as the interviews, reveal that an individual perspective on school difficulties seems to be deeply rooted in school. The identification process of special educational needs followed three models: a pedagogical model, a social model, and a medical/health model. However, the process of sorting out and defining these pupils invoked ambivalent feelings in the school personnel and the school class usually became the frame of reference for normal or deviant behaviour. Finally, the pupils’ and parent’ main concern of special support measures in school were described as a struggle for recognition and inclusion. The results are discussed with theoretical perspectives on school difficulties and special education. In the concluding discussion, it is argued that pupils with special educational needs have to balance between normality and deviance in school, but also between a pedagogical and a medical discourse by means of having a medical diagnosis in school.
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| 2. |
- Langerth, Ann
(författare)
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Endoscopic retrograde cholangiopancreatography : Perforation and long-term outcomes after endoscopic sphincterotomy
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Endoscopic retrograde cholangio pancreatography (ERCP) is a commonly used procedure in various disorders of the pancreatobiliary tract. When extracting common bile duct stones (CBDS), the major duodenal papilla is divided using a papillotome to perform an endoscopic sphincterotomy (ES). Adverse events occurring shortly after ES are well-known and include perforation which, however, is difficult to investigate due to its low frequency. ES is often used in elderly and/or infirm patients with gallstone pancreatitis and cholangitis, to prevent relapse in biliary events linked to CBDS. Subsequent cholecystectomy in these patients remains controversial. What happens in the long term after ES is still partially unknown.In Paper I, we found an increased risk for both cholangitis and pancreatitis after ES for CBDS, without synchronic relapse of CBDS and when compared with the general population was found. In Paper II, we retained the ES group, but replaced the control group with controls with a history of gallstone disease. The increased risk for both cholangitis and pancreatitis without relapse of CBDS still remains but, no higher risk for malignancy in the pancreatobiliary tract was noted.We conducted study III, a prospective follow-up after ES, to evaluate to what extent ES prevents relapse into biliary events after cholangitis and pancreatitis caused by bile duct stones. We included 100 patients who did not have earlier gallbladder surgery and who were treated for pancreatitis and/or cholangitis. The patients then underwent ES but not cholecystectomy and were followed for a mean of 42 months. None of the patients had recurrent pancreatitis and one had cholangitis. This indicates that ES alone is an alternative to cholecystectomy in the prevention of further attacks of acute pancreatitis and cholangitis.Paper IV consists of 52,140 ERCPs that were registered with GallRiks, a Swedish population based register. A total of 376 cases were registered as perforations and 75 patients had a fatal outcome. These data showed that sphincterotomy in the pancreatic duct increased the risk of death from perforation but the risk of death was reduced when ERCP was performed at a Q4 centre.
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| 3. |
- Carlsson, Jenny, 1984-
(författare)
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On Crack Dynamics in Brittle Heterogeneous Materials
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Natural variation, sub-structural features, heterogeneity and porosity make fracture modelling of wood and many other heterogeneous and cellular materials challenging. In this thesis, fracture in such complicated materials is simulated using phase field methods for fracture. Phase field methods have shown promise in simulations of complex geometries as well as dynamics and require few additional parameters; only the material toughness and a length parameter, determining the width of a regularised crack, are needed.First, a dynamic phase field model is developed and validated against experiments performed on homogeneous brittle polymeric materials, wood fibre composites and polymeric materials with different hole patterns. Then, a high-resolution model of wood is developed and related to experiments, this time without considering fracture. Attention is finally focussed on high-resolution numerical analyses of fracture in wood and other cellular microstructures, considering both heterogeneity and relative density.The phase field model is found to reproduce crack paths, velocities and energy release rates well in homogeneous samples both with and without holes. In more complicated heterogeneous and porous materials, the model is also able to simulate crack paths, but the interpretation of the length scale is complicated by the inherent lengths of the micro-structural geometry. In sum, the thesis points to possibilities with the proposed method, as well as limitations in our current understanding of both quasistatic and dynamic fracture of heterogeneous and cellular materials. The findings of this thesis can contribute to an improved understanding of fracture in such materials.
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| 4. |
- Gerén, Linda, 1962-
(författare)
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Pionic Fusion Study of the 6He Halo
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The structure of the halo nucleus 6He has been investigated in a pionic fusion experiment at the CELSIUS storage ring facility in Uppsala. The 4He(d, 6He)π+ reaction was studied 0.6 - 5.0 MeV above threshold in the centre-of-mass frame with a deuteron beam incident on a 4He gas target. The 6He ions were detected in a ΔE - E solid-state detector telescope inserted into the CELSIUS ring. The results for the total and differential cross section are presented and compared to results for the analogue reaction producing the 3.56 MeV analogue state in 6Li. A simple model of the reaction gives results consistent with earlier findings of 6He as having a spatial extent considerably exceeding that of the alpha particle. It is also shown that information about the high momentum part of the halo wave function can be extracted from the results of this pionic fusion measurement.
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| 5. |
- Isaksson, Charlotta, 1974-
(författare)
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Uthålligt lärande om värmen? : Domesticering av energiteknik i passivhus
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Den vanligaste lösningen på problemet att för mycket energi används i den byggda miljön är implementering av energieffektiv teknik. Men installation av teknik räcker sällan för att nå förväntad energibesparing: det är människor som i sin vardag använder tekniken och de använder den inte alltid på det sätt som teknikutvecklarna har tänkt sig. I avhandlingen behandlas människors vardagliga användning av energiteknik. Det innebär att fokus skiftas från produktutvecklarnas och experternas intentioner och syn på teknikens användning, till det sociala sammanhang där människor lever sitt vardagsliv.Syftet med avhandlingen är att undersöka hur energiteknik som utvecklats för att hushålla med energi och effektivisera energianvändningen domesticeras i hemmet. En fallstudie har genomförts för att undersöka hur energikonceptet för passivhus med tillhörande teknik domesticeras i hemmet. Detta energikoncept förväntas leda till ett nytt energieffektivt sätt att hantera värmen i bostaden. Fallstudien består av två intervjuomgångar med boende i passivhusen i Lindås, söder om Göteborg.Utifrån ett sociokulturellt perspektiv på lärande och begreppet domesticering analyseras hur de boende tolkar energikonceptet i passivhus, hur de på olika sätt förändrar sitt förhållande till värme och sitt sätt att hantera värmen inomhus, samt hur och varför deras engagemang för energitekniken begränsas. I avhandlingen analyseras processen där de boende med stöd av tidigare erfarenheter och olika typer av resurser efter hand gör tekniken begriplig och lär sig att hantera värmen i sitt passivhus.En slutsats är att mer uthållig energianvändning inte kan nås enbart genom att utveckla nya energitekniska lösningar, utan det krävs också att förutsättningar skapas för att människor ska kunna lära sig hantera de mer hållbara alternativen och dessutom välja dem.
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| 6. |
- Landin, Per, 1983-
(författare)
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Digital Baseband Modeling and Correction of Radio Frequency Power Amplifiers
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aspects related to behavioral modeling and correction of distortions for radio frequency (RF) power amplifiers (PAs) are treated in the thesis. When evaluating the performance of a behavioral model it is important to, first of all, use an evaluation criterion, and second, make sure that the criterion actually tells something about the behavior one wishes to describe. This is used in the weighted error spectral power ratio (WESPR) criterion by means of a frequency dependent weighting function. When the parameters of the models are estimated a suitable error criterion should likewise be used. The frequency weighting function in the WESPR is used in the extraction of the parameters. It is shown on two types of PAs that the model performance measured as WESPR can be improved while the model complexity is reduced compared to the standard frequency neutral criterion. When building a model of a system it is advantageous to take account of the physical structure and incorporate this knowledge into the model. It can improve model performance and possibly reduce the number of parameters. By starting from a physically motivated nonlinear model of a RF PA, the commonly used memory polynomial (MP) models are derived. Additionally, three novel MP model structures are derived. Using data measured on a PA it is found that two of these model structures have lower model errors while using fewer parameters than models previously published in the literature. Methods to increase the power efficiency and the linearity of RF PAs have been investigated. One of these methods is digital predistortion (DPD) which improves the linearity, thus facilitating operation at higher power levels which improves power efficiency. The other method is a signal shaping method that makes the signal more favorable to the PA by reducing the highest peaks to lower values. It is experimentally shown that the combination of DPD and signal shaping results in an increase of power efficiency in the order of 2-4 times. An instability in the feedback loop that updates the parameters of the DPD was also identified and two solutions were proposed. One solution changes the parameters of the DPD in such a way that the instability is avoided and the other changes the signal to avoid high amplitudes. The nonlinear effects of class-D outphasing amplifiers are considered. Four model structures are proposed and evaluated on data measured from two amplifiers. In order to reduce the distortions in the output signal from the amplifiers an algorithm using constant envelope amplitude (purely phase-modulated) signals is proposed. The DPD is evaluated and found to reduce the distortions in a state-of-the-art 32 dBm class-D outphasing PA to make it fulfill the linearity requirements for downlink signals used in the universal mobile telecommunications system (UMTS).
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| 7. |
- Nordhall, Ola
(författare)
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Feeling and Thinking at Work : Personal and Collective Work-Identity Predictions and Formations
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present thesis was to investigate emotional and cognitive personal and collective work-identity in predicting employees’ work-related motivation, organizational justice perceptions, general mental health and exhaustion; as well as if psychosocial working conditions might explain some of these relationships. Emotion and cognition in formation of personal and collective work-identity were also investigated. The sample consisted of 768 teachers responding to a questionnaire (Study I-IV) during spring 2016. The results showed that personal work-identity positively predicted self-determined work motivation, accounted for by the emotion component, and collective work-identity positively predicted organizational pay justice, accounted for by the cognition component (Study I). Emotional personal and cognitive collective work-identity positively predicted general mental health and negatively predicted exhaustion. Reversed relationships were found for cognitive personal and emotional collective work-identity (Study II). Teachers’ psychological job demands and resources mediated the relations between emotional and cognitive personal and collective work-identity, respectively, and exhaustion and self-determined work motivation, respectively (Study III). Emotional processes positively predicted cognitive processes, and the emotional profile showed effects on cognitive processes regarding personal work-identity formation, while cognitive processes positively predicted emotional processes, and the cognitive profile showed effects on emotional processes regarding collective work-identity formation (Study IV). In conclusion, emotional and cognitive personal and collective work-identity play significant but different roles in predicting work-related motivation, organizational pay justice as well as general mental health and exhaustion. Also, teachers’ psychosocial working conditions may contribute to explaining some of these associations. Finally, emotion and cognition may play different roles in the formation of personal and collective work-identity.
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| 8. |
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| 9. |
- Engdahl, Johan, et al.
(författare)
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Multicentre, national, investigator-initiated, randomised, parallel-group, register-based superiority trial to compare extended ECG monitoring versus standard ECG monitoring in elderly patients with ischaemic stroke or transient ischaemic attack and the effect on stroke, death and intracerebral bleeding : the AF SPICE protocol
- 2023
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 13:11
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Atrial fibrillation (AF) is a major risk factor for ischaemic stroke and transient ischaemic attack (TIA), and AF detection can be challenged by asymptomatic and paroxysmal presentation. Long-term ECG monitoring after ischaemic stroke or TIA is recommended by all major societies in cardiology and cerebrovascular medicine as a secondary prophylactic measure. However, data on stroke reduction are lacking, and the recommendations show significant diversity.Methods and analysis: AF SPICE is a multicentre, national, investigator-initiated, randomised, parallel-group, register-based trial comparing extended ECG monitoring versus standard ECG monitoring in patients admitted with ischaemic stroke or TIA, with a composite endpoint of stroke, all-cause-mortality and intracerebral bleeding. Patients aged ≥ 70 years without previous AF will be randomised 1:1 to control (standard ECG monitoring) or intervention (extended ECG monitoring). In the control arm, patients will undergo 48±24 hours (ie, a range of 24-72hours) of continuous ECG monitoring according to national recommendations. In the intervention arm, patients will undergo 14+14 days of continuous ECG monitoring 3months apart using an ECG patch device, which will provide an easy-accessed, well-tolerated 14-day continuous ECG recording. All ECG patch recordings will be read in a core facility. In cases of AF detection, oral anticoagulation will be recommended if not contraindicated. A pilot phase has been concluded in 2022, which will transcend into the main trial during 2023-2026, including approximately 30 stroke units. The sample size was calculated to be 3262 patients. The primary outcome will be collected from register data during a 36-month follow-up.Ethics and dissemination: Ethical approval has been provided by the Swedish Ethical Review Authority, reference 2021-02770. The trial will be conducted according to the ethical principles of the Declaration of Helsinki and national regulatory standards. Positive results from the study have the potential for rapid dissemination in clinical practice. Trial registration number NCT05134454.
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| 10. |
- Landin, Per N.
(författare)
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On Radio Frequency Behavioral Modeling : Measurement Techniques, Devices and Validation Aspects
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Effektförstärkare för radiofrekvensapplikationer utgör fortfarande ett av de största problemen i trådlösa kommunikationssystem. Detta beror på att dessa förstärkare är ickelinjära, har låg energieffektivitet och ger mycket distortioner. Bättre verktyg för att förstå och korrigera dessa beteenden är nödvändiga. Ett sådant verktyg är beteendemodellering. En beteendemodell kan ses som en svart låda med insignal(er) och utsignal(er). In detta fall är dessa signaler samplade basbandssignaler och den svarta lådan är en matematisk relation mellan en insignal och en utsignal. Avhandlingen behandlar några krav för beteendemodellering av nämnda system genom att presentera metoder för utvärdering och förbättring av modellernas prestanda. Detta åstadkoms genom att betrakta ett frekvensviktat felkriterium. Ett högpresterande mätsystem är också nödvändigt för experimenten. Prestandan hos det tillgängliga systemet jämförs med prestandan hos ett allmänt erkänt mätsystem, en s.k. storsignalsnätverksanalysator, genom att betrakta prestandan hos beteendemodellerna som extraheras och valideras med data från respektive mätsystem. Resultatet visar att det existerande mätsystemet har god prestanda. Ett stort problem vid beteendemodellering är att kunna sampla med tillräckligt hög hastighet. Genom att använda Zhu-Franks generaliserade samplingsteorem vid beteendemodellering kan en del av detta problem undvikas. Teoremet medför att man kan sampla med en väsentligt lägre samlingsfrekvens än vad Nyquistteoremet säger. Modeller extraheras och prestandan utvärderas genom att använda kriteriet normalized mean square error (NMSE). För stabil prediktion och korrektion av utsignalen måste robustheten hos de använda modellerna verifieras. En sådan studie som berör robustheten mot variationer i lastimpedansen har genomförts. Prestandan på direkta modeller försämras med 7 dB mätt som adjacent channel error power ratio (ACEPR). Prestanda på inversmodellen, implementerad som digital predistortion, försämras med upp till 13 dB mätt som adjacent channel power ratio (ACPR).
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