Doktorsritgerðir- HÍ
Varanleg URI fyrir þennan undirflokkhttps://hdl.handle.net/20.500.11815/84
Skoða
Nýlegt
Verk In Situ LIBS Analysis of Oxidation, Vaporization, and Phase Transformations in Molten Aluminum Alloys(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-06-24) Radsson, Mani Thor; Snorri Þorgeir Ingvarsson; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)This thesis demonstrates how in‑situ Laser‑Induced Breakdown Spectroscopy (LIBS) can be used to probe thermodynamic and kinetic phenomena in molten aluminum alloys. The results show that LIBS not only provides rapid compositional analysis but also captures vapor–liquid equilibria, oxidation behavior, and phase‑transformation dynamics in molten metal. In Al–Mg alloys, the Mg LIBS signal was found to be influenced by vapor‑phase emission, causing an exponential increase in apparent Mg concentration with temperature. Arrhenius analysis showed that this trend follows the enthalpy of Mg vaporization, confirming that LIBS directly reflects Mg vapor–liquid equilibrium. Alloying additions revealed varying degrees of thermodynamic interactions: Si, Zn, and Sn in 1-3 wt% concentrations moderately affected Mg activity, while alloying with Be, Ca, and Sr significantly reduced the temperature-dependent Mg contribution at only 0.01 wt% additions, in agreement with other studies on the influence of these group-II elements on the oxidation of Mg-containing melts. For Li‑containing alloys, the LIBS analysis showed strong signal saturation due to rapid surface oxidation and the formation of Li‑rich surface films. Time‑dependent measurements demonstrated that the Li concentration decays exponentially in the melt, with decay time increasing linearly with Mg concentration, suggesting that Mg-containing oxides have a partial blocking effect on Li removal from the melt. In primary aluminum, Li additions were shown to enhance the loss of Mg, Ca, and Sr from the melt. In Al–Ti and Al–Zr alloys, LIBS was successfully used to map liquid–solid equilibria and track real‑time formation of Al₃Ti and Al₃Zr. Measured liquidus lines agreed with thermodynamic predictions, while experiments at different cooling rates revealed different degrees of nucleation undercooling for Al₃Ti and Al₃Zr phases. Silicon additions were shown to reduce undercooling in Al–Zr alloys and affect the morphology of Al₃Zr in the solidified alloy. Overall, the work shows that molten-metal LIBS analysis is a powerful tool for studying vaporization, oxidation, and intermetallic phase formation in molten alloys, offering unique opportunities for real-time analysis in metallurgical research and industrial process monitoring.Verk Scribes and Scribal Practice in Fifteenth-Century Iceland: A Study on the Evolution of Script and Language.(University of Iceland, School of Humanities, Faculty of Icelandic and Comparative Cultural Studies, 2026-06-19) Pagani, Roberto Luigi; Haraldur Bernharðsson; Faculty of Icelandic and Comparative Cultural Studies (UI); Íslensku- og menningardeild (HÍ); School of Humanities (UI); Hugvísindasvið (HÍ)This dissertation investigates Icelandic scribal and linguistic practices during the socalled “long” fifteenth century, roughly spanning from the late fourteenth century to the early sixteenth. The period has traditionally been regarded as one of stagnation in both language and script, yet such an assessment has rarely been tested through systematic analysis. The present study re-examines this assumption by tracing selected palaeographic and orthographic developments across a corpus of fifty scribal hands drawn from manuscripts dated between c. 1375 and c. 1525. Three palaeographic and seven linguistic features were selected on the basis of their frequency, diagnostic value, and chronological sensitivity. These include, among others, the distribution of forms of the letter “a”, of the tall “s” and of the “r” rotunda on the one hand, and on the other the fricativisation of unstressed wordfinal k, the diphthongisation of e before ng and that of é, the drop of intervocalic g before i/j, the u-epenthesis, and the orthographic representation of palatal consonants. Data were gathered through systematic random sampling of images of manuscript texts and converted into quantitative tables allowing comparison between conservative and innovative forms. The results demonstrate that the fifteenth century was not a static period but rather one characterised by gradual and uneven change. Certain features reveal clear chronological trajectories, while others display persistent coexistence of competing forms. When the individual profiles of scribal hands are compared, no coherent clusters emerge that could correspond to geographical or institutional affiliations, suggesting a highly individualised scribal practice which challenges the notion of “scribal schools” or “scribal milieu”. The combination of palaeographic and linguistic data thus provides a more nuanced picture of late-medieval Icelandic manuscript culture. Far from representing a period of decline, the “long” fifteenth century appears as a dynamic phase of transition, bridging the classical and early modern stages of Icelandic writing. Not least, the findings offer a basis for refining the dating of broadly-dated manuscripts and for reassessing the evolution of Icelandic orthography and script.Verk The non-antibacterial mechanism of action of azithromycin and other macrolides in respiratory epithelium(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-06) Asbjarnarson , Arni; Þórarinn Guðjónsson; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)Epithelial barrier failure is a common denominator in multiple acute and chronic respiratory diseases. The respiratory epithelial barrier presents the first line of defence against infectious agents and other particulate matter; continuous exposure of epithelial cells results in molecular and phenotypic changes that evoke conditions such as inflammation, fibrosis, and epithelial-to-mesenchymal transition (EMT). Macrolide antibiotics are known for their off-label use in treatments of chronic respiratory diseases (CRD), primarily due to their anti-inflammatory and immunomodulatory effects. Azithromycin (AZM), in particular, has been recognized for its use in decreasing the frequency of CRD exacerbations. Our research group has previously shown that AZM maintains bronchial epithelial integrity in air-liquid interface (ALI) cell culture conditions. However, the mechanisms underlying this effect are not completely known. The aim of this thesis is to understand the non-antibiotic mechanism of action of macrolides, particularly AZM, in modulation of barrier integrity and metabolism of bronchial epithelial cells. In paper I, the effects of different macrolides (AZM, clarithromycin, erythromycin, roxithromycin and solithromycin) on gene expression and epithelial integrity in ALI culture were compared. AZM treatment, when compared to other macrolides, drastically enhanced barrier integrity, induced phospholipid retention and vesicle build-up. Analysis of gene sequencing data sets revealed AZM treatment distinctly enriched several gene sets, most notably increasing the expression of genes related to keratinocyte differentiation, establishment of skin barrier and downregulation of EMT pathways. The focus of Paper II was the potential role of AZM in EMT. AZM inhibited TGF-β1-induced upregulation of SNAI1, N-cadherin and vimentin, key features of EMT. Furthermore, AZM reduced the expression of caveolin-1 that has previously been linked to EMT. The data presented in Paper II report a potential mechanism by which AZM inhibits EMT via depletion of caveolin-1 and cholesterol from the cell membrane through their transport to a perinuclear location. The aim of Paper III was to expand on and compare the effects of the same macrolide antibiotics as those examined in Paper I, but with a focus on oxidative phosphorylation and mitochondrial function. Macrolide treatment indirectly decreased mitochondrial respiration and lowered protein levels of electron transport chain proteins. However, only AZM treatment caused an increase in reactive oxygen species at 72 hours post treatment along with a downstream increase in lipid peroxidation. The antioxidant pathway of KEAP1/NRF2 was activated and gene expression data from longer treatments (14 and 21 days) in ALI culture revealed that AZM initiated mitochondrial dynamic and protective pathways through mitohormesis. In Paper IV, AZM was compared to a nonantibacterial derivative of AZM (EP395) to determine whether the effects of AZM are distinct from its antimicrobial activity. It was shown that EP395 retained the barrier integrity enhancing capabilities of AZM along with positive enrichment of the same gene sets found to be uniquely affected by AZM treatment, indicating that these effects are distinct from the antibacterial activity. Papers V and VI focused on ventilatorinduced lung injury (VILI) in a rodent model where it was investigated whether macrolides ameliorate the negative effects caused by mechanical ventilation. It was shown that barrier failure correlated with increased expression of the pro-inflammatory cytokine IL-6 and higher tidal volumes. Furthermore, increased oxidative stress and phenotypic changes in mitochondria were observed. Finally, we reported that AZM and EP317, another derivative of AZM with reduced antibacterial activity, ameliorated pulmonary oedema, enhanced barrier integrity, and attenuated inflammatory responses caused by ventilation. Collectively, I have shown that AZM has greater effects on bronchial epithelial barrier integrity than other macrolides, that it inhibits EMT and fortifies mitochondrial resilience. I propose possible mechanistic pathways involved in the beneficial effects of AZM treatment, while recognising that additional research is needed to fully uncover AZM’s involvement in the discussed pathways.Verk BDPA radicals for DNP-NMR and a new method for RNA spin-labeling(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-06-16) Ahmad, Iram; Snorri Þór Sigurðsson; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)Dynamic nuclear polarization (DNP) is a powerful approach for overcoming the low sensitivity of nuclear magnetic resonance (NMR) spectroscopy and has extensive applications in the study of both materials and biological systems. Electron paramagnetic resonance (EPR) and fluorescence spectroscopy are highly important complementary techniques and are particularly valuable for studying nucleic acid structure and dynamics. The broader application of these methods, however, depends on the availability of suitable polarizing agents and site-specific spectroscopic probes, respectively. This thesis focuses on the development of 1,3 bisdiphenylene-2-phenylallyl (BDPA)-based polarizing agents for DNP-NMR and a facile spin labeling strategy for nucleic acids. The first part describes the development of tailored BDPA derivatives for high-field DNPNMR. The synthesis of the key precursor, tetrabromo BDPA, was first optimized. A tetraazide-BDPA building block was subsequently prepared, enabling conjugation to a variety of alkynes via copper-catalyzed azide-alkyne cycloaddition. Using this strategy, four BDPA derivatives with varied polarity, size, and steric shielding were prepared. Of these, a BDPA-dendrimer derivative exhibited enhanced persistence and superior DNP performance, achieving the highest liquid-state DNP enhancement reported to date in viscous solutions. The second part describes a noncovalent RNA spin labeling strategy based on helical stacking of small RNA hairpins, containing the rigid spin label Çm, on RNA duplexes. Complementary overhangs promoted efficient hairpin-duplex stacking, monitored by EPR spectroscopy. In addition, collaborative projects involving incorporation of rigid and semirigid spin labels and fluorophores in nucleic acids to study their structure, dynamics and interactions with proteins using EPR and fluorescence spectroscopies, are recounted.Verk Development of AsymPol- and bTurea-Derived Bis-Nitroxides for DNP-Enhanced NMR in Biological Systems(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-06-16) Wilson, Ancy Trisha; Snorri Þór Sigurðsson; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (NMR) spectroscopy has emerged as a powerful technique to unravel complex biomolecular structures at atomistic resolution. DNP serves to overcome the inherent insensitivity of NMR by the polarization transfer from unpaired electrons to nuclei of interest under microwave irradiation. The sensitivity gain conferred by DNP enables the detection of biomolecules at their physiological concentration. Nitroxide biradicals have shown to be excellent polarizing agents at 9.4 T and 14.1 T, prompting our interest in utilizing them to investigate complex systems via DNP-NMR. However, their broader applicability is limited by several factors, including synthetic challenges, lack of specificity, poor aqueous solubility, and rapid reduction in a reducing environment. This thesis describes the development of synthetic strategies for nitroxide-based biradicals to address these limitations. Firstly, a series of AsymPol-derivatives, including an isothiocyanate, a tetrazine, a maleimide, a cholesterolbased tripod, and an azide, was synthesized to enable targeting of diverse systems ranging from biomolecules to materials. These radicals enabled targeted DNP, which allows selective enhancement of signals from specific sites. Secondly, bTurea-derived bcTCOOKs and bcTmols were developed as readily accessible and water-soluble derivatives to address synthetic limitations associated with highly performing bis-nitroxide biradicals. Among these, bcTCOOK-M2 was the highest yielding and exhibited particularly high DNP sensitivity. Finally, a synthetic strategy was established for highly water-soluble, reductionresistant nitroxide radicals (43 and 44) for in-cell DNP applications. Their stability in the presence of ascorbic acid was evaluated and compared with known radicals; however, they did not exhibit sufficient stability under reductive conditions.Verk An infant diet score, BMI and asthma medication in childhood; Population-based evidence from the Icelandic Maternal and Child Health Study (ICE-MCH).(University of Iceland, School of Health Sciences, Faculty of Food Science and Nutrition, 2026-06) Jonsdottir, Jenny; Birna Þórisdóttir og Inga Þórsdóttir; Faculty of Food Science and Nutrition (UI); Matvæla- og næringarfræðideild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)Background and aim: Infant nutrition is a key determinant of both short- and long-term health. However, few population-based studies have integrated information on breastfeeding and complementary feeding into a comprehensive measure and examined its associations with childhood health outcomes. The aim of this doctoral thesis, “An Infant Diet Score, BMI, and Asthma Medication in Childhood: PopulationBased Evidence from the Icelandic Maternal and Child Health Study (ICE-MCH)”, was to investigate associations between infant nutrition, childhood BMI, and pediatric asthma medication use. Materials and methods: The ICE-MCH study includes data from electronic health registers for children born in Iceland between 2009 and 2015, forming a nationwide population-based cohort (N=30,623). Paper I of the thesis describes infant nutrition from a few weeks after birth until one year of age. Nutritional variables were obtained from records completed by primary healthcare nurses during nine routine visits with the infant and their caregiver, most often the mother. A composite measure of infant nutrition quality, the Infant Diet Score (IDS), was derived from these data, based on Icelandic infant feeding recommendations and existing infant diet scores. The IDS comprised six components: duration of exclusive and any breastfeeding, age at introduction of cow’s milk and complementary foods, an estimate of dietary variety, and use of vitamin D supplementation. Higher scores indicated greater adherence to infant nutrition guidelines. Associations between the IDS and growth outcomes were examined, with a focus on the international BMI-for-age z-scores during infancy and toddlerhood (12 and 18 months; Paper I) and childhood (2.5, 4, 6, and 9 years; Paper II). Associations between the IDS and asthma medication between ages 1 and 7 years were investigated using data from the Icelandic Prescription Medicines Register. The outcome was defined as two or more dispensations of asthma medication within a 12- month period (Paper III). In addition to descriptive analyses, linear and logistic regression models were applied, both unadjusted and adjusted for potential confounders. Results: Due to its composite nature, the IDS was calculated for the subset of children with complete nutritional data across all nine visits from 0 to 12 months of age (n = 12,848). Findings from Papers I–III showed that greater adherence to infant nutrition guidelines, reflected by a higher IDS, was associated with more favorable BMI trajectories up to 9 years of age and a lower risk of asthma medication use up to age 7. Children in the lowest IDS quintiles had higher odds of overweight and obesity (based on international definitions) at 12 and 18 months and at 6 and 9 years compared with those in the highest quintile, after adjustment for relevant maternal and birth characteristics. When examining individual components of the score, most consistently shorter duration of exclusive and any breastfeeding were associated with less favorable growth outcomes. Shorter duration of exclusive and any breastfeeding, lower use of vitamin D supplementation, and lower overall IDS were consistently associated with increased odds of having two or more asthma medication dispensations within a 12- month period between ages 1 and 7 years. Conclusions: This study demonstrates that the Infant Diet Score, a composite measure capturing overall diet quality during the first year of life, is a valuable population-based indicator of infant nutrition that can be applied in research on health outcomes. Lower adherence to infant nutrition guidelines in the first year of life is associated with less favorable growth trajectories and increased asthma medication dispensation in childhood. These findings suggest that infant nutrition is an early-life exposure that is important for subsequent child health.Verk On seismic behavior and vulnerability of building structures: Dynamic identification, condition assessment, and fragility modeling(University of Iceland, School of Engineering and Natural Sciences, Faculty of Civil and Environmental Engineering, 2026-06-10) Gautam, Dipendra; Rajesh Rupakhety, Bjarni Bessason, Hugo Rodrigues; Faculty of Civil and Environmental Engineering (UI); Umhverfis- og byggingarverkfræðideild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)Structures undergo various changes during their service life due to deterioration or external loading. These changes are the keys to design, assess, and predict structural behavior. The three pillars of structural engineering are the most governing factors to justify safety, serviceability, functionality, and operability of structures, considering forms and functions. Although independently extensively studied, coordinated efforts have not been widely practiced in structural engineering, starting from characterization to condition assessment and finally probabilistic response depiction. Aiming at coordinated dissemination of the three pillars, the present study performs system identification based modal characterization to develop period-height relationships and condition assessment under no external loading, structure undergoing deterioration, changed state of structure due to extreme loading, changed state of structure due to construction progression, and strengthened structures following various states of damage. Furthermore, many sets of seismic fragility functions have been developed for low-rise RC buildings, considering global and component level performance using empirical data. This study covers RC and stone and brick masonry buildings for dynamic identification, condition assessment, and seismic vulnerability modeling. Experimental and empirical approaches have been deployed to estimate dynamic characteristics as structural performance signatures, evolution of dynamic characteristics as signatures of changed state of the structures, and probabilistic models as signatures to quantify the exceedance probability of particular damage level in buildings and components under seismic excitation. Bayesian modeling based formulation is adopted through MCMC using Metropolis-Hastings sampling to derive period-height relationships and fragility functions. Subsequently, posterior parameter uncertainties have also been characterized.Verk Bleeding following cardiac surgery: Incidence, risk factors, complications and outcomes(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-06) Heimisdóttir, Alexandra; Tómas Guðbjartsson; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)Aims: Bleeding is a common and inevitable complication of cardiac surgery, and excessive bleeding is associated with increased morbidity, mortality, and healthcare costs. Various complications related to excessive bleeding and re-exploration have been identified, including prolonged hospital stay, increased incidence of infections, and a higher risk of 30-day mortality. Less is known, however, regarding the long-term prognosis of these patients, and results of previous studies on certain proposed risk factors have been conflicting. The aim of this thesis was to gain a better understanding of bleeding complications after cardiac surgery, especially coronary artery bypass grafting (CABG) and valve replacement surgery. The specific aims were to identify risk factors (Studies III and IV) and analyse short- and long-term outcomes (Studies I, II, and V), in order to help prevent excessive bleeding and improve patient prognosis. Methods: The project consisted of five retrospective, nationwide cohort studies. Study I was based on data from over 48,000 patients from the SWEDEHEART registry who underwent CABG and/or valve replacement surgery in Sweden between 2006 and 2015. Studies II–V included all patients who underwent CABG in Iceland between 2001 and 2022. Risk factors for excessive bleeding were assessed, as well as the relationship between excessive bleeding and preoperative use of antidepressants (SSRI/SNRI), red cell distribution width (RDW), and perioperative complications. Short- and long-term outcomes of patients re-explored for bleeding were also examined, and perioperative transfusion trends over an 18-year period in Iceland were analysed. Multivariable logistic regression was used to identify independent factors associated with excessive bleeding, re-exploration, and transfusions, while Cox proportional hazards regression analysis was used to assess long-term outcomes. Results: Re-exploration for bleeding was associated with significantly increased 30- and 90-day mortality and higher rates of perioperative complications, including stroke, acute kidney injury, and prolonged hospital stay, but was not associated with increased long-term mortality among patients who survived the initial postoperative period. Preoperative use of SSRI/SNRIs was not associated with an increased risk of bleeding, perioperative complications, or 30-day mortality. Elevated preoperative RDW was independently associated with increased 24-hour chest tube output, higher rates of red blood cell transfusion, re-exploration for bleeding, and other perioperative complications, but not with 30-day mortality. Over an 18-year study period, a significant decline was observed in the proportion of patients receiving perioperative transfusion of any blood product. This decline may have been attributed to increased awareness, improved surgical techniques, and the implementation of international transfusion guidelines and strategies such as cell salvage and point-of-care coagulation testing. The main factors associated with excessive bleeding were female sex, low body mass index, preoperative use of antiplatelet medication, and impaired renal function. Conclusions: This project provided in-depth insight into bleeding as a complication of cardiac surgery and highlighted important risk factors and predictors of severe bleeding, as well as the short- and long-term outcomes of affected patients. The findings underscored the importance of preoperative risk stratification, timely intervention, and the implementation of strategies to reduce bleeding during and after surgery. The decline in transfusion rates in Iceland over the past two decades likely reflected the positive impact of system-level improvements in bleeding and transfusion management.Verk Can a novel imagery-competing task intervention reduce intrusive memories of trauma? A study among Icelandic women(University of Iceland, School of Health Sciences, Faculty of Psychology, 2026) Thorarinsdottir, Kristjana; Andri Steinþór Björnsson; Faculty of Psychology (UI); Sálfræðideild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)Objective: Intrusive memories of trauma, experienced as vivid and distressing involuntary sensory memories, are the core clinical symptom of posttraumatic stress disorder (PTSD) and contribute to the enduring distress and functional impairment associated with the disorder. Although existing PTSD treatments are effective, they often require a detailed description of the trauma on the patient’s behalf, causing additional distress. They also depend on specialist clinical delivery, making therapists too few to deliver therapy to all those in need. These factors limit accessibility and scalability of the interventions. There is a pressing need for brief, simple and scalable interventions that minimize treatment barriers and that can be delivered remotely. The overarching aim of this thesis was to adapt to the Icelandic population and then evaluate a brief cognitive intervention designed to reduce the frequency of established intrusive trauma memories using an imagery-competing task after a memory retrieval, drawing from theories of memory reconsolidation. This is known as a novel imagery-competing task intervention (ICTI). Specifically, the intervention combines a memory reminder cue with a visuospatial task (playing Tetris with mental rotation) to disrupt sensory-perceptual features of intrusive memories. The objectives were to test the efficacy of the intervention in an Icelandic context. Further objectives were to evaluate whether the intervention would be a feasible way to reduce the frequency of intrusive memories and whether such reduction in frequency would have an impact on PTSD symptoms, depression and anxiety symptoms and functional impairment. Methods: Three studies were conducted using repeated single-case AB designs in which each intrusive memory “hotspot” was targeted individually. Study I was a single-case design with a woman with subthreshold PTSD. She monitored four intrusive memories across a four-week baseline, an eight week intervention period, and one- and three-month follow-ups. Study II was a case series of three women (two with PTSD, one with subthreshold PTSD). Each participant monitored their intrusive memories for one week at baseline, up to six weeks during the intervention phase, and again for one week at the one- and three-month follow-ups. Study III was a case series with eight trauma-exposed women, three with PTSD and three with subthreshold PTSD. The intervention was delivered face-to-face in Study I, partly remotely in Study II and entirely remotely in Study III, with guidance provided by either clinical psychologists or psychology students without specialist mental health training. Participants completed baseline, intervention, and follow-up diaries at one- and threemonths. Across all studies, the primary outcome was frequency of intrusive memories recorded in daily diaries. Secondary outcomes were PTSD symptoms, depression symptoms, anxiety symptoms, functional impairment, and acceptability and feasibility of the intervention. Results: Across the three studies, the intervention was found to be feasible, acceptable, and consistently associated with substantial reductions in intrusive memories. Results in Study I showed a 52% reduction in the frequency of total intrusive memories during the intervention compared to baseline, increasing to a 76% reduction at the one-month follow-up and a 92% reduction at the three-month followup. Improvements were also observed in PTSD symptoms, depression and anxiety symptoms, sleep, concentration, and functioning. The participant rated the intervention as an acceptable way to reduce the frequency of intrusive memories. Study II also found reductions across all three participants. One participant reported 38.8 intrusions per week at baseline, which reduced to 18.0 per week during the intervention period (54% reduction). The number of intrusive memories further reduced to 8 per week at the one-month follow-up (80% reduction) and increased to 13 (67% reduction) at the three-month follow-up. The second participant reported 10.8 intrusions per week at baseline, which reduced to 4.7 per week during the intervention period (57% reduction) with a further reduction to 1 per week at the onemonth follow-up (91% reduction) and to zero at the three-month follow-up. The third participant reported 33.7 intrusions per week at baseline, which reduced to 20.7 per week during the intervention period (39% reduction) and to 5 per week at the onemonth follow-up (85% reduction) and increased to 8 per week (76% reduction) at the three-month follow-up. All participants reported reductions in PTSD symptoms postintervention, with two also showing reductions in depression and anxiety symptoms. Participants rated the intervention as being acceptable. Study III extended these findings to remote delivery and non-specialist guidance. All eight participants showed reductions in intrusive memories from baseline to the intervention period, although reductions were minimal for two participants, overall, 6.3% to 93% reduction. At the one-month follow-up, six out of eight participants showed further reductions, 58% to 100%, and by the three-month follow-up reductions were 72% to 100%. Most participants experienced improvements in PTSD, depression, and anxiety symptoms, and functioning improved for seven out of eight participants. Participants rated the digital delivery and non-specialist guidance as highly acceptable. Conclusions: The research presented in this thesis provides evidence in support of a brief imagery-competing task intervention which can substantially reduce the frequency of long-standing intrusive memories of trauma. Furthermore, it can improve associated psychological symptoms and functioning. The intervention targeting the core clinical symptom of PTSD is low-cost, scalable and acceptable. It does not require patients to describe their trauma in detail, and it can be delivered by nonspecialists after training, thereby addressing key barriers in traditional effective PTSD treatments. The studies further demonstrate the feasibility of remote digital delivery, indicating scalability and public mental health relevance. The findings support progression to a randomized controlled trial. Overall, the thesis highlights the promise of this simple and brief intervention for reducing intrusive memories and related distress, improving access to care for trauma-exposed populations. Keywords: Intrusive memories of trauma, trauma, post-traumatic stress disorder, visuospatial task interventionVerk Disabled Women and Violence: Access to Justice(University of Iceland, School of Social Sciences, Faculty of Sociology, Anthropology and Folkloristics, 2026-06) Gjecaj, Eliona; Rannveig Traustadóttir; Faculty of Sociology, Anthropology and Folkloristics (UI); Félagsfræði-, mannfræði- og þjóðfræðideild (HÍ); School of Social Sciences (UI); Félagsvísindasvið (HÍ)This dissertation explores access to justice for disabled women who have been subjected to gender-based violence. The research was conducted in Iceland and foregrounds the intersectional nature of the multiple forms of discrimination these women face, emphasizing their right to live free from violence and abuse, and their right to access justice as enshrined in the UN Convention on the Rights of Persons with Disabilities (CRPD). Scholarship in this area remains surprisingly limited; therefore, the aim of this dissertation is to address this gap by creating new and much needed knowledge about the experiences of disabled women as well as of those who support them through the processes of detection, reporting, investigation and prosecution of violence. The doctoral research adopts an interdisciplinary human rights approach, combining disability studies, gender studies and disability human rights law. This framework emphasizes the intersecting forms of discrimination and unequal power relations that contribute to the social exclusion, marginalisation, and disempowerment of disabled women, rendering them more vulnerable to violence than both disabled men and nondisabled women. A multi-method qualitative approach was employed for data collection including 36 in-depth interviews with participants from key stakeholder groups identified as critical to the process of reporting and prosecution of the violence: disabled women, professionals working in support centres for survivors of violence, individuals within the justice system involved in reporting and prosecution, and experts in the field of disability, violence and justice. Qualitative interviews were essential in enabling an in-depth exploration of the lived experiences of the disabled women at the centre of the study. This approach recognizes and values the meanings they ascribe to their everyday experiences and ensures that the voices of marginalised groups are acknowledged. Additional data were gathered through document analysis and field observations. Document analysis comprised a detailed review of published life histories by disabled women, court documents, national laws and policies, and international human rights instruments with a particular focus on the CRPD. Field observations included attending court proceedings involving cases of violence against disabled women and visiting centres that provide support to survivors of violence. The study unfolded during the onset, progression, and aftermath of the COVID-19 pandemic, providing insights into its impacts on the lives and experiences of disabled women while also introducing methodological challenges that shaped the research process. The findings document the lived experiences of violence described by disabled women, detailing its multiple forms and complex manifestations. The study highlights the low rates of reporting and explores the multifaceted reasons underlying this, including how the women conceptualise justice in relation to the barriers they face. Through an in-depth analysis of a single court case, the research also provides a critical lens on broader issues concerning access to justice for disabled women. It identifies factors that facilitate access to justice in accordance with CRPD obligations, as well as barriers that hinder, or have the potential to hinder, such access. Rights Protection Officers (RPOs) emerged as a particularly important procedural accommodation in facilitating effective access to justice. As a result, a part of the research focused on the scope of the work performed by Rights Protection Officers and their role in securing access to justice for disabled women. A key conclusion of this research is a call for Icelandic authorities to take meaningful action to protect disabled women from the pervasive violence they face and fulfil their duty to provide reasonable and procedural accommodation within the Icelandic justice system. This includes ensuring that all professionals involved receive appropriate training and awareness-raising grounded in the human rights principles and values of the CRPD. Without such reforms, access to justice will remain inconsistent and contingent upon the particular professionals assigned to a case—effectively rendering justice a matter of chance rather than a guaranteed right.Verk Brexit: A Case Study in Post-Truth Politics and European Disintegration(University of Iceland, School of Social Sciences, Faculty of Political Science, 2026-04-27) Orlando, Vittorio; Maximilian Conrad; Faculty of Political Science (UI); Stjórnmálafræðideild (HÍ); School of Social Sciences (UI); Félagsvísindasvið (HÍ)This dissertation investigates Brexit as both a unique political event and a paradigmatic case of European disintegration, situating it within the broader context of post-truth politics. The overarching aim is to understand how ideological, structural, and communicative dynamics interact to challenge the cohesion of the European Union (EU). By combining five interlinked studies, the research develops a theory of European disintegration grounded in the role of crises, political actors, and post-truth narratives. Methodologically, the thesis employs qualitative case study designs, process tracing, qualitative content analysis, and frame analysis. Empirical materials include political speeches, campaign documents, party manifestos, media content, and EU institutional texts. The article-based format allows each publication to focus on a distinct dimension of disintegration while collectively contributing to the development of a comprehensive theoretical model. The first article analyses the causes of Brexit through process tracing, identifying the interplay between pre-existing ideological Euroscepticism, structural crises such as the Eurozone and refugee crises, and the strategic agency of political actors. It concludes that disintegration is best understood as the outcome of a triad of ideas, actors, and crises. The second article investigates the role of post-truth politics in the Leave campaign, demonstrating how misinformation and emotionally charged narratives framed EU membership as a risk. By classifying campaign materials into thematic groups, it shows how actors mobilised post-truth strategies across different arenas, confirming the centrality of communicative manipulation in disintegration processes. The third article explores Brexit’s impact on Euroscepticism in Italy and Germany. Through comparative content analysis of four Eurosceptic parties, it finds that Brexit served as a rhetorical benchmark. In Germany, the AfD openly advocated “DEXIT,” while in Italy, parties such as Lega and Fratelli d’Italia reinforced their Euroscepticism without pursuing withdrawal. Structural contexts and government participation largely explain these divergences, highlighting how Brexit influenced national discourses without producing uniform effects. The fourth article examines Brexit’s institutional consequences, focusing on differentiated integration. Analysing policy documents and official EU statements, it finds that while Brexit introduced disintegration pressures, it simultaneously reinforced differentiated integration, especially in monetary and foreign policy. This suggests that disintegration can reshape integration trajectories rather than simply weaken them. The fifth article assesses Eurosceptic narratives in the 2024 European Parliament elections, analysing materials from far-left and far-right parties. Using frame analysis, it identifies persistent themes—migration, governance, and economic sovereignty—mirroring the Leave campaign’s post-truth strategies. The findings indicate that destructive Euroscepticism remains strong, framing the EU as illegitimate, while constructive Euroscepticism advocates reform rather than withdrawal. Across the five studies, several consistent results emerge. First, political parties and institutions shape disintegration by constructing narratives that reframe EU membership as a matter of identity, security, and sovereignty. Second, ideological forces such as nationalism and economic anxiety interact with crises to provide fertile ground for disintegrative narratives. Third, post-truth politics intensifies these dynamics by privileging emotion and representation over factual accuracy. Finally, Brexit is shown to be both a cause and a symptom of European disintegration: while it has not produced immediate systemic collapse, it has reframed EU membership as reversible and provided a blueprint for future contestation. The dissertation concludes that European disintegration is a multidimensional process driven by the interaction of crises, actors, and ideational forces. Post-truth politics plays a pivotal role in this process, enabling political actors to transform crises into disintegrative opportunities. By integrating insights from Brexit and subsequent Eurosceptic developments, the thesis proposes a constructivist theory of disintegration that advances scholarly understanding of the EU’s vulnerabilities and future trajectories.Verk The Effects of Long-term Cessation of Grazing on Carbon Dynamics in Icelandic Grassland and Heathland(University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences, 2026-05-20) Klopsch, Christian; Anna Guðrún Þórhallsdóttir; Faculty of Earth Sciences (UI); Jarðvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)Large herbivores are increasingly recognised as key regulators of terrestrial carbon cycling, yet empirical evidence on how long-term cessation of grazing alters carbon dynamics and storage remains limited. The aim of this PhD research is to investigate how multi-decadal cessation of grazing influences carbon fluxes and storage in sub-arctic grassland and heathland ecosystems. The study uses a network of grazer exclosures established 20-83 years ago across 34 sites in Iceland, with paired continuously grazed land. Growing-season CO₂ exchange was quantified through extensive chamber-based flux measurements and NDVI data, and carbon storage and pathways in the plant–soil system were assessed using 201 soil profiles to 60 cm depth. The study results show that across sites, long-term cessation of grazing was associated with a 37% lower growing-season net CO₂ uptake and lower vegetation greenness relative to grazed land. In topsoil (0–10 cm), soil organic carbon stocks were 8% lower in exclosures, accompanied by 21% lower fine-root biomass, while root functional traits remained largely unchanged. Grazed grassland retained both the highest net CO₂ uptake and largest SOC stocks. Cessation of grazing caused a transition toward heathland at several grassland sites, associated with lower productivity and carbon sequestration while it had more limited effects in long-established heathlands. Collectively, the findings demonstrate that sustained extensive grazing maintains higher carbon turnover, enhances below-ground carbon inputs, and supports long-term SOC storage in sub-arctic grassland. This dissertation provides comprehensive empirical evidence that grazing can function as a nature-based solution for preserving carbon sinks in sub-arctic ecosystems.Verk Metal ion escape and gas rarefaction in high power impulse magnetron sputtering(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-05-29) Barynova, Kateryna; Jón Tómas Guðmundsson; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)High power impulse magnetron sputtering (HiPIMS) is an advanced ionized physical vapor deposition (IPVD) technique that uses almost the same hardware as dc magnetron sputtering (dcMS), but is more flexible in tuning film characteristics. Compared to conventional dc magnetron sputtered films, thin films produced by HiPIMS typically have enhanced properties, such as better crystallinity, higher mass density, and improved phase composition, primarily due to low-energy ion bombardment during the film growth process. However, the broader use of HiPIMS in industrial applications is constrained by the main disadvantage: often a significantly lower deposition rate. This drawback is mainly attributed to the back-attraction of the film-forming species after they have been ionized in the dense plasma near the cathode target. The thesis focuses on addressing this primary limitation of HiPIMS by investigating the physics governing the discharge, and the relationship between sputter yield and deposition rate. The central goal was to analyze and further develop the ionization region model (IRM) of HiPIMS discharges to optimize the deposition process. The research involved computational modeling, including studies on working gas rarefaction across multiple target materials, the detailed modeling of discharges with chromium, aluminum, and graphite targets in various gas mixtures (e.g., Ne/Ar), and the analysis of the results obtained from the simulations. The main conclusion, supported by the data analysis of the IRM simulation results for various target materials under diverse discharge conditions, is that the sputter yield dictates the back-attraction probability of the sputtered species. The sputter yield is shown to be a key factor that significantly changes the discharge composition, electron temperature, degree of gas rarefaction, and, consequently, the possible limit on deposition rate and overall discharge characteristics. Furthermore, the sputter yield determines which process is mainly responsible for working gas rarefaction. In conclusion, this work establishes that the target sputter yield is important for controlling and optimizing the HiPIMS discharge. The thesis serves as an introduction to the physical processes investigated, while the detailed results of the work are presented in the attached articles. The work also includes a supplementary experimental part focused on measurements of the ionized flux fraction (IFF) in the deposition flux. This experimental data served for constraining one of the parameters within the IRM, thereby improving the model’s predictive power.Verk Lifandi texti - Áhrif þýðinga á sögu leiklistariðkunar á Íslandi(Háskóli Íslands, Hugvísindasvið, Íslensku og menningardeild, 2026-05-18) Gunnlaugsdóttir, Tinna Þórdís; Gauti Kristmannsson; Íslensku og menningardeild (HÍ); Icelandic and Comparative Cultural Studies (UI); Hugvísindasvið (HÍ); School of Humanities (UI)Í þessari rannsókn — sem ég kýs að kalla „Lifandi texta“ þar sem hún snýr fyrst og fremst að texta sem ætlaður er til lifandi flutnings af leiksviði — verður saga og þróun leiklistariðkunar á Íslandi rakin út frá hlutverki og vægi erlendra áhrifa og fyrirmynda. Þýðingar erlendra leikrita eru í kjarna rannsóknarinnar en einnig margvísleg hagræðing og endurritun texta fyrir leiksvið. Samhliða verður leitast við að varpa ljósi á þýðingarhugtakið með vísan til þýðingasögunnar og helstu fræðikenninga á því sviði, en með sérstöku tilliti til leikbókmennta og sviðshandrita, eða þess sem tekur til eða heimfæra má upp á slíkan texta. Helstu rannsóknarspurningarnar snúa að erlendum áhrifum, hvaðan þau komu, hvernig þau birtust og síðast en ekki síst hvaða merkjanlegu spor þau skildu eftir sig – og þar með vægi þeirra og áhrif á þróun leiklistarinnar í landinu. Niðurstöður rannsóknarinnar sýna að erlendar fyrirmyndir hafi vísað veginn í árdaga og að stælingar erlendra gamanleikja hafi verið sá efniviður sem gerði leiklistinni kleift að festa rætur á Íslandi. Íslensk leiklist og innlend leikritun rekur þannig upphaf sitt til þýðinga, auk þess sem ýmiss konar erlend áhrif og þýðingar í margbreytilegum og margvíslegum myndum og skilningi þess orðs, hafa til þessa dags stuðlað að áframhaldandi vexti starfsins og viðgangi þess. Í fyrsta kafla ritgerðarinnar er fjallað um þýðingar og þróun fræðigreinarinnar í stærra samhengi. Leitast er við að varpa ljósi á stefnumótandi skoðanir skálda og heimspekinga fyrri tíðar og athyglinni síðan beint að Íslandi og staðan hér á landi rakin að nokkru. Staldrað er við fyrstu þýðingar fagurbókmennta á síðari öldum á Íslandi og nálgun þýðenda er sett í samhengi við orðræðuna um mismunandi nálgun þýðenda að bókmenntatexta, en hér á landi voru það ljóðaþýðendur sem ruddu brautina og settu þeim sem á eftir komu fagurfræðileg og skáldskaparleg viðmið, ekki síst þýðendum bundins leiktexta. Umræðunnar um sérstöðu leiktexta er einnig getið og hugmynda þeirra fræðimanna sem einna fyrstir settu fram hugmyndir um æskilega nálgun að slíkum textum. Í öðrum kafla ritgerðarinnar er saga leiklistariðkunar í landinu rakin að nokkru og vísað til dæma af hlutverkaleikjum og skemmtanahaldi á fyrri öldum sem rekja má til þeirrar norrænu arfleifðar sem landnemar báru með sér til landsins. Því er síðan fylgt eftir hvernig þeirri arfleifð reiddi af í gegnum aldirnar og þá hvernig flest það sem menn gerðu sér til skemmtunar féll í ónáð eða var beinlínis bannað. Þrátt fyrir það var það látið óáreitt þegar hlutverkaleikir tóku að þrífast á skólaskemmtunum í Latínuskólanum í Skálholti og á átjándu öld og rakið hvernig þeir leikir þróuðust smám saman í frumstæða leiklistariðkun, en færð eru rök fyrir því að það starf hafi markað upphafið að ástundun þeirrar listgreinar í landinu í nútímaskilningi þess orðs. Sagan er síðan rakin frá því að Latínuskólinn flutti endanlega til Reykjavíkur um miðja nítjándu öld og leikstarf og skemmtanir skólapilta urðu hluti af bæjarmenningunni. Einstaklingar í bænum stóðu einnig fyrir stöku leiksýningum og fljótlega voru stofnaðir leikhópar og félög um starfið. Efniviðurinn var að mestu evrópskir gamanleikir, aðallega danskir, sem bárust til landsins í gegnum Kaupmannahöfn. Sumt var leikið á dönsku, sérstaklega framan af, annað í íslenskum þýðingum, stælingum eða staðfærslum, eins og vísað er til með dæmum. Sagan er síðan rakin til loka nítjándu aldar og getið um hvernig erlendar fyrirmyndir urðu aflvaki fyrstu innlendu leikritanna sem náðu máli. Í kaflanum er einnig komið inn á hina menningarpólitísku umræðu og leikritaþýðingar sem hluta af endurreisn þjóðtungunnar. Í þriðja kafla ritgerðarinnar er athyglinni beint sérstaklega að þýðingum sígildra leikbókmennta. Yfirlýst markmið var að reyna á þanþol og blæbrigði tungumálsins og sýna fram á hæfni þess til að skila stórbrotnum erlendum leikskáldskap. Lýsandi dæmi eru tekin úr fyrstu þýðingum sígildra leikbókmennta á íslensku og vitnað til þeirrar umræðu sem fylgdi útgáfu þeirra á prenti. Samhliða er komið inn á kenninguna um fjölkerfi samfélagsins, eða helstu ytri áhrifaþætti og viðleitni áhrifavalda til að stýra umræðunni. Einnig er í kaflanum varpað ljósi á stöðu leikrita og leikbókmennta innan bókmenntakerfisins á Íslandi, en með vönduðum þýðingum sígildra leikrita stækkaði mengi leikbókmennta auk þess sem þýðingar sköpuðu fordæmi og urðu grundvöllur frekari þróunar. Í kafla fjögur er innlend leiklistarsaga undir, allt frá því að leiklistarstarf í Reykjavík varð nokkuð samfellt við lok nítjándu aldar til fullgildrar atvinnustarfsemi um miðja tuttugustu öldina og áfram inn á fyrsta fjórðung þeirrar tuttugustu og fyrstu. Framboð leikrita er rannsakað sérstaklega og sýnt fram á að þýdd erlend leikrit hafi verið í meirihluta sviðsettra verka og sá efniviður sem fleytti starfinu áfram. Einnig er varpað ljósi á hvernig erlendarstefnur og straumar höfðu áhrif á verkefnaval og fólu í sér nýjar áskoranir. Sérstaða leiktexta er áréttuð og þær kröfur sem gera verður tiltexta sem beinlínis er þýddur til lifandi flutnings á leiksviði. Umræðan um skort á frambærilegum innlendum leikritum varð hávær með opnun Þjóðleikhússins og leikskáldunum kennt um, en starfsumhverfi höfunda var lítt hvetjandi, eins og rakið er og sama átti við um þýðendur. Í kafla fimm er sjónum beint að þeim margvíslegu erlendu áhrifum sem bárust til landsins með fólki sem menntaði sig og starfaði erlendis. Nýsköpun og tilraunastarf í erlendum leikhúsum varð að fyrirmynd þegar hér voru stofnaðir fyrstu sjálfstæðu atvinnuleikhóparnir. Einnig er komið inn á þau áhrif sem erlendir gestaleikstjórar höfðu á starfsemi atvinnuleikhúsanna með því að kynna og fylgja eftir nýrri nálgun að sígildum leiktextum. Tekin dæmi af stefnumótandi samstarfi erlendra og innlendra leikhúslistamanna sem leiddi til ögrandi túlkunar á efni sígildra leikrita. Einnig er komið inn á endurritun og hagræðingu og þau verkfæri þýðingafræðinnar sem nýta má í þágu nýtúlkunar á sígildum leiktexta, sem aftur er til þess fallin að endurnýja erindi hans og tilhöfðun. Varpað er ljósi á slíka nýtúlkun með raundæmum úr íslensku leikhúsi á síðari árum. Samhliða er vitnað til listrænna stjórnenda og þýðenda þeirra sömu verkefna, þar sem þeir ræða og skýra ásetning sinn og nálgun. Hér er hið nýskapandi afl þýðinga í formi endurritunar og hagræðingar áréttað og um leið hið nýskapandi afl leiklistarinnar til að opna áhorfendum nýjan skilning á eldri texta. Í kafla sex er athyglinni beint að höfundinum og þýðandanum í íslensku leikhúsi, en skilin þar á milli eru oft á tíðum óljós. Varpað er ljósi á hvað hugtakið „þýðing“ getur umfaðmað vítt svið, en það á jafnt við þegar texti er þýddur frá einu tungumáli til annars og þegar formi hugverks er breytt, eins og þegar skáldsaga eða annað höfundarverk á öðru formi er endurritað og því hagrætt fyrir leikhúsmiðilinn. Það á einnig við um túlkun leikara á leiksviði, eða þegar texti er túlkaður í lifandi flutningi. Í kaflanum er einnig varpað ljósi á stöðu höfundarins, sem lengst af stóð nokkuð höllum fæti í íslensku leikhúsi, en svo virðist sem það hafi tekið stjórnendur leikhúsanna tíma að átta sig á mikilvægi þess að hlúa að starfi þeirra. Sama á við um þýðendur sem oft fengu lítið svigrúm til að skila vinnu sinni. Hér er einnig er komið inn á umræðuna umleikgerðir og hvað telst fullgilt leikrit, eða hvað sé rétt að flokka sem höfundarverk og hvað endurvinnslu texta. Hér er dregið í efa það sjónarmið að uppruni hugmynda skipti sköpum og staðhæft að það sé úrvinnslan sem allt veltur á. Staða innlendrar leikritunar og nýsköpunar er síðan rædd í sögulegu samhengi og umræðunni fylgt eftir með samanburði, sem byggir á samantekt á fjölda innlendra og erlendra leikrita á verkefnaskrá Leikfélags Reykjavíkur og Þjóðleikhússins frá upphafi og til leikársins 2024-2025. Í kaflanum eru birt súlurit og línurit sem byggja á þessum upplýsingum og sýna fram á yfirgnæfandi meirihluta þýddra leikrita á verkefnaskrá beggja leikhúsanna frá upphafi, en samantektin er birt í heild sinni í viðaukum. Síðan eru niðurstöður dregnar saman og loksfylgja lokaorð höfundar.Verk The role of atrial fibrillation and aortic stiffness in brain structure and function(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026) Gardarsdottir, Marianna; Davíð O. Arnar; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)Atrial fibrillation is the most common sustained cardiac arrhythmia and is associated not only with stroke and heart failure, but also with reduced brain volume and cognitive impairment. While thromboembolism explains part of this relationship, growing evidence suggests that additional mechanisms, including vascular, inflammatory, and hemodynamic processes, contribute to brain vulnerability in atrial fibrillation. Aortic stiffness, a manifestation of vascular aging, has similarly been linked to structural brain changes and cognitive decline. The overall aim of this thesis was to investigate whether disturbances in central hemodynamics represent a common pathway linking AF and aortic stiffness to alterations in brain perfusion, brain structure, and cognitive performance. In a population-based cohort of older adults, total cerebral blood flow measured by phase-contrast magnetic resonance imaging and estimated brain perfusion were significantly lower in individuals with persistent atrial fibrillation compared with those in sinus rhythm. Individuals with paroxysmal atrial fibrillation had similar cerebral blood flow to those in sinus rhythm. Persistent atrial fibrillation was also associated with smaller relative brain volume assessed by magnetic resonance imaging, whereas cognitive performance did not differ significantly between groups. To explore whether atrial fibrillation-related hypoperfusion might be reversible, total cerebral blood flow and brain perfusion were measured before and after electrical cardioversion using phase contrast and arterial spin labeling magnetic resonance imaging. Brain perfusion increased significantly in individuals who achieved and maintained sinus rhythm, whereas no significant change was observed in those who remained in atrial fibrillation. In a separate cohort, aortic stiffness assessed as carotid-femoral pulse wave velocity measured by applanation tonometry was inversely associated with brain perfusion measured with arterial spin labeling magnetic resonance imaging. Higher aortic stiffness was also associated with smaller relative total brain, grey matter, and white matter volumes, and with greater white matter hyperintensity burden. In multivariable analyses, aortic stiffness independently predicted lower brain perfusion whereas chronological age was the strongest determinant of structural brain measures. In conclusion, both atrial fibrillation and increased aortic stiffness were associated with reduced brain perfusion and markers of structural brain vulnerability. Restoration of sinus rhythm was accompanied by improvement in brain perfusion, supporting a dynamic hemodynamic mechanism. Together, these findings suggest that hemodynamic alterations represent an important pathway linking cardiovascular aging to brain vulnerability and highlight brain perfusion as a potential early marker of brain risk.Verk Zoning for Zero - Climate impacts of zoning plans in a Nordic context(University of Iceland, School of Engineering and Natural Sciences, Faculty of Civil and Environmental Engineering, 2026-05-20) Jama, Teemu; Jukka Heinonen; Faculty of Civil and Environmental Engineering (UI); Umhverfis- og byggingarverkfræðideild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)This thesis examines the climate impacts of urban planning, with a focus on its primary institutional outcome: zoning plans. Methodologically, it contributes by analysing planning paradigms, typically addressed qualitatively in normative terms, through quantitative methods based on high-resolution spatial data of the built environment classified by their zoning plan denotations. Using this mixed-method approach grounded in Critical Realism, the thesis provides quantitative evidence on how land-use zoning influences the carbon footprint of urban development, with a qualitative analysis of the mechanisms behind this evidence. The quantitative results from the Nordic case cities challenge prevailing assumptions from two directions. On the one hand, high-density, efficiency-oriented zoning seems to fail to enable argued low-carbon lifestyles, instead reinforcing high-carbon behaviours through consumerism and increased travel. On the other hand, lower-density zoning, widely deemed unsustainable, tends to dominate also in cities in locations where residents have lower carbon intensities and overall emissions, even when income and household types are controlled. The findings reveal zoning’s causal power to shape global emissions from the bottom up, although it is currently applied counterproductively. The thesis demonstrates and argues that using zoning plans to manage climate impacts, rather than building rights with per capita–based efficiency metrics, is not only a feasible and historically defensible reconception of zoning but also essential for urban planning to retain its public mandate as a libertarian paternalistic policy tool for climate-friendly development.Verk “What’s Love Got to Do with It?” The Role of Gender in Time Used on Care, Love and Work among Doctorate Holders(2026-05-22) Hjálmsdóttir, Andrea; Guðbjörg Linda Rafnsdóttir; Faculty of Sociology, Anthropology and Folkloristics (UI); Félagsfræði-, mannfræði- og þjóðfræðideild (HÍ); School of Social Sciences (UI); Félagsvísindasvið (HÍ)Over the last few decades, the share of doctorate degrees earned by women has increased considerably. Despite this trend, there is a scarcity of studies addressing gender disparities among doctorate holders, working within and outside academia. Although accounting for a relatively small portion of the labour force, doctorate holders' experiences are important, as they can provide an important insight into how well-educated people who often enjoy privileged working arrangements and flexibility, negotiate gender roles at home and in the workplace. The main aim of the research introduced in this thesis was to gain a better understanding of how and if time used on care, love labour and work, influences gendered outcomes on the career trajectories of doctorate holders working within and outside academia. The findings draw on quantitative and qualitative research data. In terms of quantitative data longitudinal individual register data from Iceland between 1997 and 2017 was used and the population analysed were doctoral graduates holding five to 20-year-old degrees. The average total earnings of male and female doctorate holders were compared in relative values, either depending on their field of study or employment within or outside academia. The findings based on the qualitative data are derived from two datasets: the first dataset comprised 32 open-ended interviews conducted with doctorate holders in Iceland, 16 men and 16 women, working within and outside academia; the second dataset comprised open-ended interviews with five men and five women working in a higher education institution in British Columbia, Canada. The findings from the quantitative study reveal a continuous gender gap in total earnings between the fifth and the tenth career years, regardless of the field of study or whether employment is within or outside academia. The novelty from the findings based on the qualitative data is mainly two folded: firstly, it provides multifaceted findings on work-family balance among doctorate holders working within and outside academia. The academics expressed more complex feelings about their daily lives than those working outside academia. The findings suggest that women, academics especially, experience limitless, boundaryless and invisible labour, both at home and at work, causing them considerable stress, while the men, within and outside academia, can selectively distance themselves from burdening caring roles at home and at work. Despite all the participants enjoying privileged working arrangements and flexibility, the participants in this research described having difficulties drawing lines around working hours. This applied especially to the participating academics, who, despite enjoying the most working arrangement flexibility, described working in a 'greedy' institution that absorbed all their time. Secondly, the findings offer a new insight into the different, yet strikingly similar, realities of academics in Iceland and Canada. This is a new perspective, to my knowledge. The most significant national difference observed in the findings was that welfare policies and having access to the extended family, played a role in career decisions among Icelanders. However, the similarities among Canadians and Icelanders in terms of stress experienced were remarkable, as the institutional structures of the academia as a workplace tailor the academics' working life very closely. The success of Iceland in terms of gender equality compared to Canada, is undermined by the structures of higher education institutions that demand long working hours and commitment and fosters competition. The study offers new insights by leveraging love labour and care as theoretical tools for analysing work-family balance and the career trajectories of doctorate holders working in and outside academia. Despite advancement in gender equality and implementation of several initiatives to advance gender equality by the government of Iceland, the findings of this thesis reveal highly traditional gendered division of labour among doctorate holders, illustrated by the fact that undertaking primary care is not central to men's identity. Such divisions of labour are maintained by patriarchal organizational structures and gendered power relations, resulting in highly gendered outcomes both at home and in the workplacesVerk Positional Leverage in Distant Institutional Environments: Insights from a Multilevel Context(University of Iceland, School of Social Sciences, Faculty of Business Administration, 2026-05) Ólafsdóttir, Bryndís; Erla Sólveig Kristjánsdóttir; Faculty of Business Administration (UI); Viðskiptafræðideild (HÍ); School of Social Sciences (UI); Félagsvísindasvið (HÍ)This compilation thesis investigates internationalization and positional leverage within an institutionally distinct but developed host country environment. Adopting a holistic perspective, the research emphasizes the meso- and micro-level dynamics of internationalization, while situating them within the shaping influence of the macrolevel, institutional environment. It addresses gaps in the existing market entry literature related to cross-level dynamics, the role and positional leverage of institutional networks in the support environment, and the adaptation strategies of internationalizing firms. Employing a qualitative methodology, this exploratory research adopts a Constructivist Grounded Theory approach with simultaneous data collection and analysis, with the objective of constructing a theory and theoretical extension grounded in empirical field data. This aimed to provide insights into the institutional environment and the experiences of managers within internationalizing high-technology firms, as well as institutional actors within the support network. The research primarily relies on in-depth semi-structured interviews conducted on-site in Japan, Denmark, Iceland, and Sweden. Additionally, case studies and text analysis are utilized to enable triangulation, capture institutional dynamics across levels, and contextualize actor perspectives. Social constructivism underpins the philosophical stance of the thesis, emphasizing the interpretation of social phenomena, the complexity of perspectives, and the existence of multiple realities within the context. The qualities of the compilation papers are best captured through three unifying characteristics: theory development, interdisciplinary diversification, and contextualization. The results reveal significant findings from two research streams. The research consists of four journal articles, two published and two under review, referred to as ‘papers’ in the thesis. The first research stream, focused on institutional networks, encompasses the first three papers. It uncovers the positional power of these support networks within the bureaucratic host country environment. This power stems from the network's legitimized position and social status in the market, which enhances its leverage in accessing influential power players. Conversely, the antecedents and dynamics of supranational coopetition (simultaneous cooperation and competition) built on collective identity and closeness are also examined. It reveals how the nested tensions and competing interests characterizing this paradox can undermine the effectiveness and potential benefits of collaboration within the institutional networks and aid stakeholders. The second research stream, centered on high technology firms, comprises the fourth and final paper. This research illustrates how firms transition from outsidership to insidership by strategically developing their network position. It complements the first stream by examining how SMEs respond to institutional dynamics through strategic adaptation and capability development. They achieve this by leveraging both business and non-business actors to improve communication with local customers. It also highlights how firms learn and adapt to the market by enhancing four types of dynamic capabilities: culture-adjusting, network-shaping, establishment-reconfiguring, and service-improving. It demonstrates how there are both assets and liabilities associated with being an insider and an outsider. In conclusion, the institutionally distinct and multilayered structures of distant sociopolitical environments, coupled with the overall complexity and uncertainty of the global market, continue to pose significant challenges for Western firms and organizations during market entry. This thesis identifies two key strategies for facilitating smoother access. Firstly, home country institutional networks can act as valuable liaisons, enabling firms to navigate these challenging environments more effectively. They provide positional leverage within bureaucratic systems and capitalize on longstanding regional alliances. However, achieving success in regional collaboration requires balancing paradoxical tensions arising from competing interests and implementing improved governance through higher-level institutional support and leadership. Secondly, internationalizing firms can address the challenges of their liability of outsidership by adopting strategic positioning. By leveraging local actors to build trust and legitimacy and by enhancing their unique dynamic capabilities to adapt to the environment, these firms can significantly improve their chances of survival and success. The thesis contributes to internationalization studies and the broader field of organizational sociology through its interdisciplinary approach. It makes a notable impact on institutional theory by highlighting the connection between organizational legitimacy and status, and is further enriched by incorporating the concept of power to explain positional leverage. Additionally, the thesis significantly advances the coopetition approach by integrating paradox theory and game theory. It introduces the novel concept of supranational coopetition to explain the complexities of regional collaboration. It also extends the Uppsala internationalization process model by refining and advancing the conceptualization of network outsidership and its link to dynamic capabilities. These theoretical contributions are solidly grounded in rigorous empirical research and thorough analysis.Verk Enumerating score sequences and permutations by inversions and forbidden patterns(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026) Franklín, Atli Fannar; Anders Karl Claesson; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)This thesis studies the enumeration of score sequences and permutations. The first paper settles a conjecture of Hanna on a recursion for the number of score sequences of a tournament, derives a closed formula, and gives a quadratic-time algorithm. The second presents generating functions for permutations with few inversions: those with as many inversions as elements, and those with a fixed number of inversions fewer than elements. The third continues on the theme of inversions, enumerating pattern-avoiding permutations by inversions for all patterns of length at most 3. The fourth and last paper explores how to obtain bounds on the number of 1324-avoiding permutations by encoding permutations as walks in a directed graph.Verk Novel Hybrid Quantum-Classical Computing Algorithms Enhancing Satellite Remote Sensing Applications for Earth Observation(University of Iceland, School of Engineering and Natural Sciences, Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, 2026-04) Delilbasic, Amer; Prof. Dr. Morris Riedel; Faculty of Industrial Engineering, Mechanical Engineering and Computer Science (UI); Iðnaðarverkfræði-, vélaverkfræði- og tölvunarfræðideild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)Earth observation (EO) is increasingly driven by large-scale remote sensing (RS) data, acquired from satellite and airborne platforms across diverse temporal and spatial resolutions. These datasets are characterized not only by volume, but by complex properties such as multi-source heterogeneity, high dimensionality, nonlinear feature distributions, and spatio-temporal variability. Processing such data at operational scale introduces significant algorithmic and computational challenges, particularly in high resolution environmental monitoring and planetary-scale inference tasks. Quantum computing (QC) offers a computational paradigm fundamentally different from classical computing, leveraging the principles of quantum mechanics to perform operations in high-dimensional state spaces. This theoretical advantage makes QC a compelling candidate for selected EO tasks, especially those involving combinatorial optimization and learning tasks. However, the limited qubit fidelity and scale of current quantum hardware constrain their direct applicability to operational applications in Earth observation. This PhD thesis investigates the application of annealing-based and circuit-based quantum algorithms to EO, as well as the integration of quantum algorithms with classical devices, such as those in high-performance computing (HPC) environments. It examines acquisition scheduling and data classification tasks within EO workflows. Experiments assess practical algorithmic benefits, computational scalability, and constraints imposed by hybrid quantum-classical execution. Results demonstrate that quantum modules, when carefully embedded into HPC architectures, can enhance selected stages of EO pipelines, specifically using quantum machine learning and quantum optimization approaches.