Publikationer från Umeå universitet
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Reciprocal effects between illicit drug use and mental health conditions among healthcare workers in Sweden : A one-year follow-up study
No full textBackground: Research suggests a comorbidity between illicit drug use and mental health conditions. However, it remains unclear whether illicit drug use serves as a risk factor for, or a consequence of, mental health conditions in healthcare workers (HCWs). This study aimed to 1) examine the prevalence of illicit drug use among HCWs in Sweden and 2) investigate the bidirectional relationship between illicit drug use and mental health conditions(i.e., depression and burnout). Methods: Data from the 2022 and 2023 Longitudinal Occupational Health Survey in Healthcare Sweden (LOHHCS) were used. The data included 3280 HCWs (50.3 % physicians and 49.7 % nurses). Questionnaires assessed illicit drug use frequency, burnout complaints (BAT-12), and depression (SCL-CD6). Cross-lagged panel models (CLPMs) were used to examine the reciprocal relationships over the two studied time-points between illicit drug use and mental health conditions. Results: The prevalence of illicit drug use in 2022 was 1.3 %, which increased slightly to 1.6 % one and a half years later, in 2023. Using two-wave panel data, results revealed a bidirectional effect between illicit drug use and burnout. However, while depression was associated with subsequent illicit drug use, the reversed association was not observed. Conclusions: These findings suggest that illicit drug use plays different roles in relation to burnout and depression among healthcare workers. This highlights the importance of integrated treatment strategies and preventive measures that address both illicit drug use and mental health conditions—especially burnout—simultaneously
Benchmarking foundation models and parameter-efficient fine-tuning for prognosis prediction in medical imaging
No full textBackground and Objectives: Despite the significant potential of Foundation Models (FMs) in medical imaging, their application to prognosis prediction remains challenging due to data scarcity, class imbalance, and task complexity, limiting their clinical adoption. This study introduces the first structured benchmark to assess the robustness and efficiency of transfer learning strategies for FMs compared with convolutional neural networks (CNNs) in predicting COVID-19 patient outcomes from chest X-rays. The goal is to systematically compare fine-tuning strategies, classical and parameter-efficient, under realistic clinical constraints related to data scarcity and class imbalance, offering empirical guidance for AI deployment in clinical workflows. Methods: Four publicly available COVID-19 chest X-ray datasets were used, covering mortality, severity, and ICU admission, with varying sample sizes and class imbalances. CNNs pretrained on ImageNet and FMs pretrained on general or biomedical datasets were adapted using full fine-tuning, linear probing, and parameter-efficient methods. Models were evaluated under full-data and few-shot regimes using Matthews Correlation Coefficient (MCC) and Precision–Recall AUC (PR-AUC) with cross-validation and class-weighted losses. Results: CNNs with full fine-tuning performed robustly on small, imbalanced datasets, while FMs with Parameter-Efficient Fine-Tuning (PEFT), particularly LoRA and BitFit, achieved competitive results on larger datasets. Severe class imbalance degraded PEFT performance, whereas balanced data mitigated this effect. In few-shot settings, FMs showed limited generalization, with linear probing yielding the most stable results. Conclusions: No single fine-tuning strategy proved universally optimal. CNNs remain dependable for low-resource scenarios, whereas FMs benefit from parameter-efficient methods when data are sufficient
Implicit and explicit (in)justice on the route to Paris : an analysis of justice expressions in the Paris Agreement, EU-, and Swedish climate-forest policy mixes
No full textForests are central to climate change mitigation, and there is consensus that climate transition efforts must be just. However, the “just transition” concept often functions as a boundary object, leading to ambiguity in its implementation. Statements of commitment to just transitions therefore require scrutiny as to what a just transition is meant to entail, what kind of justice transition policies seek to ensure, and how these ambitions are envisioned to be realised in practice. Yet, it is precisely this that is missing in the current academic literature, especially in the forest sector context. This study addresses this gap by analysing implicit and explicit justice expressions in the Paris Agreement, and EU- and Swedish climate-forest policy mixes, thereby providing empirical insights on the ‘what’ and ‘how’ of just transitions in the forest sector. Using a newly developed framework that combines the policy mix concept with distributional, recognitional, and procedural justice dimensions, the analysis reveals shared narrow foci in just transition understanding, discrepancies between expressed just transition motivations, and inconsistent mechanisms for implementation across governance levels, thus risking stakeholder disengagement. The results call for explicit discussions in policy debate on how justice can be ensured in transition efforts in the forest sector across levels, regardless of the specific understanding of justice that is adhered to, and open societal debate on what a just transition ultimately ought to mean in a forest context. Furthermore, policy makers must take the step from ambiguous promises to concrete instruments to support forest stakeholders through the transition
Determination of the thermo-electronic and structural properties of polycrystalline metals and single-crystal semiconductors
No full textThis study explores the correlation between thermal, electrical, and structural properties of metals, alloys, and single-crystal semiconductors using photothermal techniques, electrical methods, and X-ray diffraction. Polycrystalline metals (Al, Pt, Ti, Cu, AISI 1030 steel, α-brass) and semiconductors (Si, GaSb-Te) were systematically analyzed. Thermal diffusivity was measured using Frequency Domain Photoacoustic (FDPA), and thermal conductivity and volumetric heat capacity using the Thermal Relaxation Method (TRM). A thermal diffusivity image for a Si sample was taken to show the influence of mechanical damage on the thermal transport properties. The structural properties were determined using X-ray diffraction, while the electrical properties were evaluated using the Van der Pauw method. The results show a strong correlation between the thermal, electrical, and structural properties of the materials, specifically with respect to crystallite size and space group. The thermal conductivity is influenced by the crystallite size, while electrical conductivity varies due to extrinsic factors, especially for polycrystalline metals. These results suggest that the Wiedemann-Franz theory needs to be re-evaluated by considering both intrinsic and extrinsic influences on material behavior
Upper-secondary school segregation in Stockholm metropolitan area : the relationship between commuting distance and school characteristics
No full textAlthough free school choice policies are often proposed as strategies to decouple residential and school segregation, research has found that they may actually increase segregation. This study investigates an underexplored aspect of these policies: the role of commuting in influencing school segregation patterns. Using Swedish register data from Stockholm Metropolitan Area, we analyse ethnic and socioeconomic segregation across residential neighbourhoods and upper-secondary schools. We examine students' distances to the nearest schools offering their chosen programs and their actual commuting distances in relation to the schools' characteristics. Our findings reveal that students with immigrant backgrounds, despite living closer to the nearest schools offering their chosen programs than native peers, tend to travel longer distances to attend their chosen schools. For native students, choosing nearby schools is associated with selecting more privileged institutions that have higher proportions of native students and higher average income levels. In contrast, students with immigrant backgrounds often travel longer distances to reach schools with characteristics similar to those attended by native students. These results challenge simplistic assumptions about the segregation-reducing effects of free school choice policies and highlight the complex interplay among the uneven distribution of educational opportunities, home-to-school mobility, and school selection strategies
Characteristics of bark and wood of Norway spruce infested by spruce bark beetle and blue-stain fungi : relevance for biomass utilization
No full textRecent droughts have accentuated problems with attacks of the European spruce bark beetle (SBB) (Ips typographus) on Norway spruce (Picea abies), one of the most important tree species in European forestry. SBB attacks are typically accompanied by infestation with Ophiostomatoid fungi causing blue stain. The chemical composition of sapwood and bark from spruce trees infested by SBB, or by both SBB and blue-stain fungi (BSF), was investigated and compared to corresponding fractions from non-infested reference (REF) trees. While sapwood from infested trees showed higher carbohydrate:lignin (C:L) ratios (SBB, 2.21; BSF, 2.47) than sapwood from non-infested trees (REF, 2.17), BSF bark showed lower C:L ratio (0.81) than REF bark (1.23). For BSF sapwood and bark, and SBB bark, the fractions of extractives were half or less than half of that of the corresponding REF materials. Group analysis using GC-FID showed significantly (p ≤ 0.01) lower levels of resin acids, fatty acids, steryl esters, and triglycerides in BSF materials than in REF materials, a phenomenon that was, however, not observed for sterols. Analysis of subgroups and individual fatty acids, resin acids, and sterols identified using GC-MS revealed complex patterns, in which many, but not all, substances exhibited lower values in BSF and SBB materials than in REF materials. Overall, the results point towards the possibility to utilize a larger portion of wood logs from trees infested by beetles and fungi for value-added applications, such as pulping, rather than as fuel wood
Standardized mortality ratio and long-term stroke incidence after PFO closure
No full textBackground: Closure of a patent foramen ovale (PFO) is frequently recommended in patients with cryptogenic stroke. Long-term outcomes in real-world settings remain unknown. Objectives: This study analyzed standardized mortality ratio (SMR), subsequent stroke, and associated risk factors after PFO closure. Methods: National registers on congenital heart disease and stroke were cross-linked to identify individuals who underwent PFO closure between 2001 and 2018. The ratio of observed to expected deaths was calculated (SMR). Data were analyzed using survival analysis and Cox regression. Results; A total of 827 patients (60.5% males, median age 47.9 years, IQR: 40.0-55.6 at the time of PFO closure) were included and observed for a median duration of 8.0 years (IQR: 4.8-11.0). During follow-up, 23 patients died, SMR was 0.65 (95% CI: 0.41-0.98). A total of 34 ischemic strokes occurred, yielding an incidence rate of 0.51 events per 100 patient-years. Among the 34 patients who experienced a subsequent stroke, 27 were receiving antithrombotic therapy at the time of the event. New-onset atrial fibrillation following PFO closure was associated with an increased risk of subsequent ischemic stroke (HR: 8.2; 95% CI: 2.6-25.8), as was active/previous smoking (HR: 2.5; 95% CI: 1.2-5.1). Conclusions: Patients undergoing PFO closure demonstrated a lower all-cause mortality compared to the general population. The observed rate of subsequent ischemic stroke was consistent with findings from previous randomized controlled trials. New-onset atrial fibrillation following PFO closure and active/previous smoking emerged as modifiable risk factors
Food-related sensory activities for children in educational settings : a scoping review
No full textHands-on activities, where children explore food with their senses, are of interest for their potential to promote healthy eating. Various food-related sensory activities (FRSA) have been developed as interventions, but design, delivery and outcome variation challenge a robust evaluation of programs. Some argue that a focus on health is narrow and that FRSA could foster other competences, including non-health dimensions of sustainability. The objective of this scoping review was therefore to examine insights from the scientific literature regarding types, aims, perceived benefits, outcome measures and connections to sustainability of FRSA targeting children in educational settings. PRISMA-ScR was used. Three databases were searched in Spring 2024, resulting in 25 included articles. The FRSA were categorized into two main types and four subtypes. The most common aims, perceived benefits, and outcome measures were related to improving children's healthy eating. It has also been suggested that FRSA might foster critically conscious consumers and socially competent individuals, and support product development. Yet, these aspects were only partially evaluated in the studies reviewed. While environmental dimensions of sustainable eating were recognized, some of the competences related to being critically conscious and socially competent may also be important for sustainable development. Future research may explore FRSA's potential contributions to outcomes other than physical health
Transcriptomic analysis of two wheat genotypes in the presence of the pathogen Zymoseptoria tritici and the biological control agent Clonostachys rosea
No full textBiological control agents (BCAs) are reported to control plant diseases by directly targeting pathogens or indirectly by enhancing the plant's immune system. It has also been reported that plants exhibit genetic variation for compatibility with BCAs, ultimately impacting biocontrol efficacy. This study explored transcriptomic host responses of two winter wheat genotypes differing for biocontrol efficacy of the fungal BCA C. rosea in controlling septoria tritici blotch disease caused by the fungus Zymoseptoria tritici . Leaves of winter wheat genotypes NGB6704 (high biocontrol efficacy) and NGB348 (low biocontrol efficacy) were spray inoculated with C. rosea , Z. tritici, or their co-inoculation and were harvested at 8 h, 16 h, 32 h, and 40 h for differential gene expression analysis. The results indicate genotype-dependent and time-dependent responses in gene expression towards C. rosea and Z. tritici . Induction of several defense-related genes associated with pattern-triggered immunity and effector-triggered immunity was also observed in interactions with C. rosea exclusively and in the presence of Z. tritici . NGB348 showed a stronger expression of defense-related genes when inoculated with C. rosea at early time points, while NGB6704 exhibited a stronger response at 40 h, emphasizing the differential responses to the presence of C. rosea by the two genotypes, ultimately affecting STB disease development. Cross-referencing differentially expressed genes with genes segregating for C. rosea biocontrol efficacy identified genes associated with receptor-like protein kinases, chitinases, oxalate oxidases, and E3 ubiquitin-protein ligases. Further microscopic and functional validation studies are recommended to determine the intricate nature of plant genotype-specific interactions
Short rainbow cycles for families of small edge sets
No full textIn 2019, Aharoni proposed a conjecture generalizing the Caccetta-Häggkvist conjecture: if an n -vertex graph G admits an edge coloring (not necessarily proper) with n colors such that each color class has size at least r , then G contains a rainbow cycle of length at most ⌈ n / r ⌉ . Recent works (Aharoni and Guo, 2023 [1] ; Aharoni et al., 2023 [3] ; Guo, 2025 [8] ) have shown that if a constant fraction of the color classes are non-star, then the rainbow girth is O ( log n ) . In this note, we extend these results, and show that even a small fraction of non-star color classes suffices to ensure logarithmic rainbow girth. We also prove that the logarithmic bound is of the right order of magnitude. Moreover, we determine the threshold fraction between the types of color classes at which the rainbow girth transitions from linear to logarithmic