Publikationer från Umeå universitet
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New constraints on the absolute age and duration of the Paleocene-Eocene Thermal Maximum (PETM) from ash layer +19 in Denmark
No full textPrecise age constraints for the onset and duration of the Paleocene–Eocene Thermal Maximum (PETM) areessential for understanding the mechanisms that triggered and sustained this major climate perturbation.However, establishing a precise PETM geochronology is complicated by uncertainties in orbital tuning and acurrent lack of precise radiometrically dated marker horizons. An early Eocene rhyolitic ash layer named +19 is apromising marker horizon due to its distinct geochemistry, its occurrence in key offshore archives, and wellpreservedoutcrops in Denmark such as Stolleklint, where it conformably overlies PETM strata. We present anew high-precision U-Pb zircon age of 55.331 ± 0.053/(0.060)/[0.080] Ma for ash +19, supported by a new Ar-Ar age of 55.424 ± 0.115/(0.116)/[0.320] Ma within uncertainty. The ash +19 U-Pb age enables direct comparisonwith ash SB01–1 in Svalbard that was erupted during the PETM carbon isotope excursion (CIE), yieldinga 454 ± 90 kyr interval between the two layers. This provides a robust geochronological link from the PETM toash +19 that is independent of stratigraphic interpretations. Using end-member PETM durations (94–170 kyr),we estimate the time between the PETM onset and ash +19 as 528–604 ± 102 kyr, which is significantly shorterthan the 862 ± 20 kyr interval derived from astronomical tuning. Adopting the longer helium isotope-basedPETM duration yields an onset age of 55.935 ± 0.102 Ma, with a CIE recovery end at 55.700 Ma. A shorterPETM duration requires a younger PETM onset age. The positive ash series in Denmark, correlating with theoffshore Balder Formation, is now constrained to a 250 kyr interval between 55.367 and 55.117 ± 0.080 Ma.This refined age model provides a robust framework for testing and improving early Eocene astronomical timescales
Inhibition of soluble epoxide hydrolase in endotoxin induced pig lung injury
No full textPharmacological inhibition of soluble epoxide hydrolase has been shown to attenuate lung injury development in rodents exposed to bacterial lipopolysaccharide. To investigate if these effects can be reproduced in larger animals, we tested soluble epoxide hydrolase (sEH) inhibition using an sEH inhibitor 1-adamantanyl-3-{5-[2-(ethylethoxy)ethoxy]pentyl}urea (AEPU) in a porcine model of lipopolysaccharide-induced acute lung injury. AEPU was selected from 23 sEH inhibitors based on IC50 values and metabolic stability profiles established by a fluorescent based activity assay and porcine liver microsomal test, respectively. Hydrolysis of fatty acid epoxides to their corresponding diols is catalyzed by sEH. Inhibition of sEH reduces this conversion, leading to an accumulation of epoxides relative to diols. Hence, AEPU-treated subjects (n = 9) showed metabolic signs of effective in vivo inhibition of the target enzyme reflected in an increased epoxide/diol ratio of 12 (13)-epoxyoctadecenoic acid to 12,13-dihydroxyoctadecenoic acid compared to placebo-treated controls (p = 0.026). However, there was no difference in lung injury development or survival in subjects treated with the rapidly metabolized AEPU compared to placebo-treated controls (n = 10). In conclusion, administration of the soluble epoxide hydrolase inhibitor AEPU did not attenuate endotoxin induced lung injury with lipopolysaccharide in pigs under the severe conditions tested here
Schematic Network Extraction using Multimodal Generative Models : A Performance Evaluation of GPT-4o
No full textExtracting structural information from images is a task traditionally handled using object detection and rule-based methods. This thesis explores whether general-purpose multimodal language models, specifically GPT-4o, can interpret technical images and generate structured outputs without task-specific fine-tuning. The potential benefit of this approach lies in streamlining information retrieval for organizations handling large volumes of visually complex data, potentially reducing the need for extensive datasets typically required for training traditional computer vision systems. Technical images in this study are represented by electrical circuit diagrams. GPT-4o was evaluated on its ability to identify components, produce consistent and accurate responses, and generate netlists from circuit images. Two datasets were used for evaluation: one synthetically generated, and one manually created. Ground truth data was generated using traditional object detection and image processing techniques. Three model configurations were tested: the original GPT-4o model, a retrieval-augmented generation (RAG) version, and a labeled version where component symbols were annotated with textual labels in the image. The labeled configuration achieved the highest performance across all tasks, suggesting that embedded textual cues strongly support accurate and consistent predictions. The RAG setup, in contrast, often underperformed, possibly due to confusion introduced by loosely relevant context. Netlist generation was the most challenging task for all configurations. The results show that general-purpose multimodal models have some potential for structured visual understanding, but also clear limitations in handling complex domain-specific tasks. Overcoming these limitations will likely require methods that go beyond using the models in their current form, such as hybrid approaches, memory-based reasoning, and task-specific fine-tuning
Mesh removal in groin hernia surgery : a long-term nationwide population-based register study
No full textBackground: Nowadays, groin hernia repair with mesh is a gold standard procedure in western countries. Yet, foreign body reaction and mesh infection are feared complications. This study aimed to investigate the prevalence and risk factors for mesh removal due to foreign body reaction and mesh infection after groin hernia repair. Method: This is an observational nationwide population-based register study with the use of prospectively collected data from the Swedish Hernia Register. All patients 15 years or older with a groin hernia repair registered between 1992 and 2022 were eligible. The primary outcome was the prevalence of re-surgery with mesh removal. The secondary outcome was risk factors for re-surgery with mesh removal. Results: Of 363,664 groin hernia repairs during this 30-year-long study period, 211 (0.06%) had a re-surgery with mesh removal. The proportion of female groin hernia repairs was higher in the mesh removal group (15.2%) compared with the nonmesh removal group (7.9%). The adjusted multivariable Cox regression analysis for the risk of re-surgery with mesh removal demonstrated significantly increased hazard ratios for female (2.80, confidence interval: 1.70–4.63), emergency (3.43, confidence interval: 1.94–6.03), open anterior mesh (2.76, confidence interval: 1.61–4.72), and combined anterior/posterior mesh (predominately mesh plugs) (3.98, confidence interval: 1.84–8.57) groin hernia repairs, and for patients below the total median of 63 years (2.61, confidence interval: 1.78–3.81). Conclusion: The groin tissue's tolerance for an implanted mesh after a groin hernia repair can be considered high where re-surgery for mesh removal due to foreign body reaction and mesh infection is rare. Female sex, younger patients, emergency repairs, and mesh plugs were most evident associated risk factors for such re-surgery
Polygenic prediction of body mass index and obesity through the life course and across ancestries
No full textPolygenic scores (PGSs) for body mass index (BMI) may guide early prevention and targeted treatment of obesity. Using genetic data from up to 5.1 million people (4.6% African ancestry, 14.4% American ancestry, 8.4% East Asian ancestry, 71.1% European ancestry and 1.5% South Asian ancestry) from the GIANT consortium and 23andMe, Inc., we developed ancestry-specific and multi-ancestry PGSs. The multi-ancestry score explained 17.6% of BMI variation among UK Biobank participants of European ancestry. For other populations, this ranged from 16% in East Asian-Americans to 2.2% in rural Ugandans. In the ALSPAC study, children with higher PGSs showed accelerated BMI gain from age 2.5 years to adolescence, with earlier adiposity rebound. Adding the PGS to predictors available at birth nearly doubled explained variance for BMI from age 5 onward (for example, from 11% to 21% at age 8). Up to age 5, adding the PGS to early-life BMI improved prediction of BMI at age 18 (for example, from 22% to 35% at age 5). Higher PGSs were associated with greater adult weight gain. In intensive lifestyle intervention trials, individuals with higher PGSs lost modestly more weight in the first year (0.55 kg per s.d.) but were more likely to regain it. Overall, these data show that PGSs have the potential to improve obesity prediction, particularly when implemented early in life
Hållbarhetsrapportering ur företagsperspektiv : - En studie om svenska företags hållbarhetsarbete och dess effekter på aktiemarknaden
No full textSammanfattning Bakgrund: År 2017 infördes lagen om hållbarhetsrapportering i Sverige. Börsnoterade stora bolag har fått krav på att informera om deras hållbarhetsarbete bredvid eller integrerat i den finansiella rapporten. Vissa företag hade redan börjat följa internationella standarder inom detta ämne före 2017, och för vissa andra krävdes en större omställning efter 2017. Tidigare studier visar på motsägelsefulla samband mellan företags finansiella prestation och hållbarhetsrapportering. Syfte: Syftet med denna studie är att undersöka om lagen har påverkat den finansiella prestationen i börsnoterade svenska företag. För att göra detta undersöker studien närmare hur börsen har utvecklats under perioden 2015–2018. Studien syftar även till att undersöka hur kvalitén på hållbarhetsrapporten påverkar företagens finansiella prestation på börsen. Metod: Kvalitativ metod används i studien genom en kategorisering av 29 utvalda svenska börsnoterade företag. I urvalet inkluderas företag från olika etiska organisationer, bland annat Ethical Trading Initiative Sverige och Carnegie Fonder, samt företag verksamma i utsatta branscher. Detta resulterade i ett blandat urval mellan stora och större bolag, där endast 8 bolag är med i OMXS30. Kvantitativ metod används för att jämföra årlig avkastning (CAGR) mellan ovan nämnda kategorier och börsindexen OMXS30 och SIXRX. Resultat och slutsats: Studien hittar inget signifikant samband mellan hållbarhetsrapporteringen, kvalitén av rapporten och bolagets kursutveckling. Statistiskt signifikanta avvikelser har hittats för vissa kategorier vid jämförelse mot OMXS30 men inte vid jämförelse mot det större indexet SIXRX. Mer undersökningar och data om etisk listade bolag i Sverige är intressanta för framtida forskning
Investigating the influence of smartphones on affective responses and time perception in exercise
No full textThis experimental study examined the influence of smartphones on affective responses and time perception in exercise. Twenty-four physically active participants (16 females, 8 males; Mage = 24.40, SD = 4.35) completed randomised conditions alternating between hard intensity cycling and seated rest whilst their smartphone was: a) used to view videos; b) present but not viewed; or c) out of sight. In each condition, participants produced a target amount of time (i.e., 37s) during the trial and estimated the trial’s duration upon completion (i.e., 330s). Participants’ feeling state, perceived exertion, and heart rate were recorded at each measurement of time perception during and following each trial. One-sample t-tests and repeated measures ANOVAs indicated that smartphones significantly affected participants’ perception of time during and following intervals of cycling and rest. Participants perceived more time had passed than chronometric time during cycling; this effect was most significant when viewing their smartphone. Participants estimated that the duration of each trial was less than actual chronometric time, although they were more accurate when they viewed their smartphone during the trial. Participants reported the greatest positive affect when viewing their smartphone, although it was not associated with time estimation accuracy. These findings highlight that highly trained exercisers overestimate the passage of time during physical activity, yet upon completion, they perceive they exercised for a shorter amount of time than reality. Smartphones can distort time perception and influence affective responses to exercise; this may have implications for the evaluation of physical activity, intentions to exercise, and health behaviours
Implementation and evaluation of a new optical path difference calibration method in frequency-comb-based Fourier transform spectroscopy
No full textBroadband optical frequency combs (OFCs) in combination with Fourier transform spectrometers (FTSs) offer state-of-the-art precision in studying molecular ro-vibrational transitions. However, the frequency accuracy of such systems is limited by accurate calibration of optical path difference (OPD), which can be measured using a monochromatic reference laser as a ruler. Conventional path-parallel OPD calibration methods suffer from inaccuracies in optical path matching and requires a time-consuming iterative wavelength calibration process. This thesis presents the implementation and evaluation of an alternative OPD calibration method using a copropagating near-infrared continuous-wave (NIR–CW) laser that is frequency-locked to a comb mode. This approach eliminates the need for wavelength calibration of the reference laser while improving path matching with the OFC. The NIR–CW laser with a wavelength inside the molecular important NIR region falls within the bandwidth of the OFC, providing means to frequency-lock the reference laser to a nearby comb mode. This provides a basis where the wavelength can be found from known parameters and thus eliminates the wavelength calibration time. The method is experimentally validated through cavity-enhanced Doppler-broadened methane absorption spectra and compared to a conventional calibration method. We also include a discussion about system design considerations like beam combination and separation techniques, noise assessments and distortion analysis. Results showed that the NIR–CW calibration method accurately determined the reference wavelength up to some integer multiples of the OFC repetition rate. However, noise evaluation against the conventional calibration method found challenges in reaching comparable noise levels due to signal leakage between the OFC and reference detectors
Empower our growth as athletes : voices of Swedish athletes with intellectual disability
No full textBackground: People with intellectual disability participate in organised sports to a lesser extent than people in general. The aim of this study was to explore the motivation for engaging in sports among athletes using the theoretical framework of sense of belonging. Method: Semi-structured online interviews were carried out with athletes (N = 15, 8/7 women/men, 29.5 ± 9 years) with intellectual disabilities. Results: The main theme ‘Empower me to grow as an athlete—adapt the support to help me develop my sport skills and social aspects’ showed that motivation, competence, perception, and opportunities were important factors for engaging in sports. Support was an important factor for creating adapted opportunities. Conclusion: Athletes with intellectual disabilities have motivation, want to feel competent, and to be athletes who belong in sports and develop as such. They also appreciate coaches giving adapted support that enhances understanding and promotes inclusion in the sport community