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Metagenomic insights into the diet and past Kolyma Lowland habitat from the intestinal content of a Late Pleistocene steppe bison
No full textDuring the last cold stage (115-11.7 cal kya BP), the non-glaciated part of Arctic Eurasia exhibited a distinctive plant composition consisting of steppe and xerophilous arctic plants. This vegetation formed the Pleistocene mammoth steppe, which provided a habitat for large herbivores like mammoths (Mammuthus primigenius) and steppe bison (Bison priscus). In this study, we analyzed the DNA sequences of well-preserved plant material from the intestinal tract of the frozen mummy of an extinct steppe bison discovered in the Kolyma Lowland, Northeastern Russia in 2009. Radiocarbon dating placed the specimen at >48 kyr. We leveraged genome-wide and skimmed genome accessions to maximize the retrieval of sequenced reads for identification. In line with macrofossil evidence, we identified alkali grass (Puccinellia), indicating high salinity, and Larch (Larix) in the DNA data of the steppe bison sample. The occurrence of larch north of the current tree line indicates warm temperatures during the growing season. Additionally, we confirmed the presence of plant genera typically associated with steppes and productive meadows under open and arid soil conditions such as Artemisia, Tanacetum, Koeleria, Festuca, Puccinellia, Taraxacum, Alopecurus, and Poa, while Phippsia suggests high soil water content, at least locally. We also attempted to infer the likely most closely related species for each genus. The most abundant authenticated genera, Artemisia and Puccinellia, align with their known prevalence in the mammoth steppe, reflecting broader environmental signals beyond the steppe bison's diet. Hence, the use of metagenomic approaches in combination with comprehensive reference databases offered insights into steppe bison diet, allowed us to obtain a more detailed view of the mammoth steppe vegetation, and provided extended interpretations of soil conditions
Abelian spectral topology of multifold exceptional points
No full textThe advent of non-Hermitian physics has enriched the plethora of topological phases to include phenomena without Hermitian counterparts. Despite being among the most well-studied uniquely non-Hermitian features, the topological properties of multifold exceptional points, -fold spectral degeneracies (EPs) at which also the corresponding eigenvectors coalesce, were only recently revealed in terms of topological resultant winding numbers and concomitant Abelian doubling theorems. Nevertheless, a more mathematically fundamental description of EPs and their topological nature has remained an open question. To fill this void, in this article, we revisit the topological classification of EPs in generic systems and systems with local symmetries, generalize it in terms of more mathematically tractable (local) similarity relations, and extend it to include all such similarities as well as nonlocal symmetries. Through the resultant vector, whose components are given in terms of the resultants between the corresponding characteristic polynomial and its derivatives, the topological nature of the resultant winding number is understood in several ways: in terms of (1) the tenfold classification of (Hermitian) topological matter, (2) the framework of Mayer-Vietoris sequence, and (3) the classification of vector bundles. The classification scheme further predicts the existence of topological bulk Fermi arcs protected by a ℤ2-invariant, induced by nonlocal symmetries, dubbed ℤ2-protected Fermi arcs. Our work reveals the mathematical foundations on which the topological nature of EPs resides, enriches the theoretical understanding of non-Hermitian spectral features, and will therefore find great use in modern experiments within both classical and quantum physics
Bispecific brain-penetrant antibodies for treatment of Alzheimer's disease
No full textThe emerging class of bispecific antibodies represents a significant advancement in Alzheimer's disease (AD) immunotherapy by addressing the limited brain concentrations achieved with conventional monoclonal antibodies. The majority of bispecific antibodies developed for AD treatment utilize transferrin receptor (TfR1)-mediated transcytosis to enhance blood-brain barrier (BBB) penetration, resulting in higher and more uniform brain concentrations compared to conventional antibodies. This improved delivery has demonstrated superior efficacy in reducing brain amyloid-beta (A beta) burden. Additionally, TfR1-mediated delivery may help mitigate adverse effects such as amyloid-related imaging abnormalities (ARIA). This is likely achieved by a reduction in antibody accumulation at vascular A beta deposits, resulting from the combined effects of lower dosing and a different brain entry route when using bispecific antibodies. Besides targeting A beta, bispecific antibodies have been engineered to address other key pathological features of AD, including tau pathology and neuroinflammatory targets, which are critical drivers of disease progression. These antibodies also show promise in diagnostic applications, particularly as radioligands for antibody-based positron emission tomography (immunoPET), leveraging their rapid brain delivery and efficient and specific target engagement. Moreover, the principles of bispecific antibody technology have been adapted for use beyond immunotherapy. The incorporation of TfR1-binding domains into enzymes, antisense oligonucleotides, or viral vectors such as adeno-associated viruses broadens their therapeutic potential. These approaches may enable more efficient treatment strategies, not only for AD but also for other neurological disorders, by facilitating the delivery of diverse therapeutic agents across the BBB
Supported in a time of need - first-time parents' perceptions of a Swedish extended home visiting program
No full textBackgroundHome visiting programs offer a way of delivering child health services to families that need them the most, based on socioeconomic and psychosocial conditions. Following evaluations of the implementation of a successful multiprofessional home visiting program in the Stockholm region, an extended version, Together for a safe start, was tested in four municipalities in the middle and southern parts of Sweden targeting first-time parents and immigrant parents having their first child in Sweden.AimTo explore parents' perceptions of an extended Swedish home visiting program conducted by a nurse and a social service counselor.MethodsInterviews with 17 parents (12 mothers and 5 fathers) who had participated in the program were conducted. Among the 17 interviews, 11 were conducted in Swedish, 4 in Arabic and 2 in English by a multilingual interviewer. The data were coded inductively and analyzed using thematic analysis. The findings were discussed and validated with parents from the community who advised the research team.ResultsThree main themes were identified, each with two subthemes (1). Trust was created in the comfort of the home, with the subthemes 'Home environment had many advantages', and 'Team's way of working created trust'; (2) The information on child health and development was valuable, with the subthemes 'Practical information and advice were useful' and 'Information on child development gave guidance'; and (3) Socioemotional support kept the parents' worries at bay, with the subthemes 'Mental well-being of the parents was cared for' and 'Parents felt supported in their new role'. Areas for improvement included mitigating the fear of social services, paying more attention to fathers' mental health and providing more written information.ConclusionThe home environment, adaptability to parents' needs, a combination of practical information on the child's development, and emotional support to parents were underscored as vital components of a successful home visiting program. The results reaffirm the potential of extended home visiting programs to increase trust and make child health services accessible, as well as bridge the gap between immigrant parents and societal services
Repeated polyploidization shapes divergence in floral morphology in Lithophragma bolanderi (Saxifragaceae)
No full textPolyploidization is an important driver of evolution and diversification in flowering plants. Here, we assess how repeated polyploidization may have shaped diversification of floral morphology in Lithophragma bolanderi (Saxifragaceae). This species comprises multiple cytotypes and varies geographically in its interactions with specialized pollinating moths in the genus Greya (Prodoxidae). Past studies have shown that coevolution with these moths has favored particular suites of floral characters but does not fully explain local and regional floral diversification. We combined phenotypic and genomic data from more than 1,800 individuals from 40 L. bolanderi populations spread across its entire range. Flow-cytometric analyses revealed a geographic mosaic of populations comprising one to four of three dominant (diploid, tetraploid, hexaploid) and three rare (triploid, pentaploid, octoploid) cytotypes. Whole-genome resequencing of a subset of populations suggested that polyploids arose from multiple autopolyploidization events, rather than a single event and/or through hybridization, albeit with some signals consistent with low levels of introgression from the congener Lithophragma glabrum. Quantification of flower traits from plants grown in a common garden showed that cytotype explained more than 15% of the variation in floral morphology, with polyploids showing more variability than diploids. Experimental induction of neopolyploids directly induced phenotypic changes but also indicated that local selection may have favored subsequent convergence in floral morphology among cytotypes in natural populations. Collectively, this comprehensive and integrative approach provides insights into how variability generating processes, such as polyploidization integrates with selection from species interactions to shape local floral diversification
The Janus face of Rassemblement National : An analysis of the gender values of women supporting a radical right populist party
No full textThis paper investigates the radical right gender gap, which, after decades of persistence, has seen a sudden shrinkage. Whereas in the past men voted much more for radical right parties than women, this gap has now decreased despite these parties’ prominent anti-gender politics. In the case of the French radical right populist party Rassemblement National (RN), women now make up almost as large a part of the voter base as men. This thesis aims to explore the gender values among women expressing support for RN, in order to provide a possible explanation for this change. Following Schwartz’s basic value theory, the hypothesis is that French women have experienced a conservative shift from pro-gender to anti-gender values, which makes the RN more attractive to them. Data from the European Value Survey is used to measure the statistical correlation between gender values and women’s support for RN in a regression analysis, as well as to investigate a possible occurrence of a shift towards more conservative gender values among women between 2008 to 2017. The study also controls for female RN voters’ attitudes towards the EU and immigrants, in line with previous research that correlates support for populist parties with a rejection of universalism (anti-EU) and prioritization of security (anti-immigrant). The results show a strong correlation between female RN support and low confidence in the EU plus discontent with immigrants, but no significant statistical correlation or indication of a conservative shift in gender values. This leads the thesis to suspect that anti-immigrant attitudes and a superficial pro-gender rhetoric play a large part in attracting women to the party, rather than their anti-gender values.
Chaperone-Mediated Regulation of Tau Phase Separation, Fibrillation, and Toxicity
No full textBiological condensates are involved in several essential processes but may also be tangled into disease progression in protein misfolding diseases such as Alzheimer's disease and tauopathies. One hallmark of these disorders is the appearance of fibrillar aggregates formed by microtubule-stabilizing Tau protein. Notably, Tau can also assemble into biological condensates and droplets via liquid-liquid phase separation (LLPS). The molecular mechanisms of the conversion of functional Tau toward insoluble fibrils, potentially via LLPS processes, remain largely unknown, and efficient treatment approaches to target toxic pathways and species are still missing. Here, we show that the molecular chaperone-like Bri2 BRICHOS domain efficiently inhibits full-length Tau fibril formation and subsequent neurotoxicity by specifically suppressing secondary nucleation processes. Further, at substoichiometric ratios, Bri2 BRICHOS modulates the potency of Tau to form droplets, incorporates into Tau droplets, and alters the dynamic behavior of Tau. In contrast, at superstoichiometric Bri2 BRICHOS ratios, Tau droplet formation is abolished. Finally, Bri2 BRICHOS reduces Tau fibril toxicity in electrophysiological experiments on hippocampal slice preparations. Taken together, Bri2 BRICHOS targets molecular processes related to protein misfolding, where our study provides molecular insights into how the inhibition of secondary nucleation pathways and modulated droplet formation are eventually linked to attenuated neurotoxicity
Nato på schemat : En samhällskunskapsdidaktisk analys av elevers uppfattningar och attityder till Nato
No full textMot bakgrund av Sveriges Nato-medlemskap och att Nato har fått en tydligare roll i läroplanen för Gy25, har denna studie undersökt hur elever i kurserna samhällskunskap 1b och 1a1 uppfattar Nato som ett fenomen samt vilka attityder de har till ett svenskt medlemskap. Studien bygger på en enkätundersökning med huvudsakligen kvalitativa essäfrågor, kompletterad med en kvantitativ fråga. Studien har en fenomenografisk och variationteoretisk anknytning som ligger till grund för elevernas uppfattning av Nato. Vidare används en kvantitativ analysmetod och en tematisk analysmetod för att analysera elevernas attityder till Nato. Analysen baseras på 65 enkätsvar från elever på två olika gymnasieskolor. Enkätsvaren analyserades och placerades först i ett utfallsrum med tre beskrivningskategorier. Därefter identifieras två stycken kritiska aspekter som utmärker skillnaderna mellan uppfattningarna hos elever. Dessa två kritiska aspekter blir viktiga för samhällskunskapslärare att lägga fokus på i undervisningen. Det är värt att ha i beaktning att resultatets pålitlighet begränsas då dessa kritiska aspekter inte har undersökts i relation till aktiv undervisning om Nato i samhällskunskap. Vidare genomförs en kvantitativ analys för att belysa huruvida eleverna ställer sig positivt eller negativt till Nato. Resultatet visar att eleverna var svagt positiva till Nato. Till sist genomförs en tematisk analys av elevernas attityder och resultatet visar att det fanns fem olika kategorier som baseras på de svar eleverna gav, dessa är: trygghet och skydd, neutralitet och självständighet, rädsla för Ryssland, rädsla för krig samt kunskap och erfarenhet
Design and Comparison of High-Power Bidirectional Isolated DC-DC Converters for Energy Storage Systems : Dual Active Bridge and CLLC Resonant Converter
No full textAs electric vehicles (EVs) and battery energy storage systems (BESS) scale in power and capacity, compact and efficient bidirectional power conversion systems are required to enable reliable and high-performance operation. Enabling functionalities such as vehicle-to-grid (V2G) and grid-to-vehicle (G2V) requires converters capable of both delivering and receiving energy with minimal losses and high power density. This thesis presents a comparative evaluation of two silicon carbide (SiC)-based bidirectional isolated DC-DC converter topologies: the Dual Active Bridge (DAB) and the CLLC resonant converter. The study is conducted under operating conditions of 600–900 V and 150–225 kW, with the converters acting as the essential DC-DC interface between the DC-link and the battery while ensuring galvanic isolation for safety. The methodology combines detailed PLECS simulations of conduction and switching behavior in SiC MOSFETs with analytical models for transformer core and winding losses, including skin and proximity effects. Transformer optimization, soft switching conditions and thermal performance are also investigated to ensure reliable operation under high-frequency, high-power conditions. The simulation results demonstrate that both converters achieve high efficiency through soft switching, with peak values of 98.83% for the DAB and 99.12% for the CLLC at 200 kW. Total losses were found to be 2.1–3.0 kW for the DAB and 1.8–2.9 kW for the CLLC across the studied battery operating range. Thermal analysis further confirmed that transformer temperatures remained below 42°C under full load, while the use of ferrite UU cores and litz wire windings resulted in low magnetic losses, enabling high power density. The comparative analysis highlights clear trade-offs: the DAB offers simpler control and scalability, making it attractive for practical high-power applications, whereas the CLLC achieves slightly higher efficiency at the cost of increased control complexity. These findings provide practical guidelines and insights for design of next-generation high-power bidirectional converters in EV and BESS applications
The effect of wetlands on hydrological low flow signatures in Swedish catchments
No full textWetlands are globally distributed ecosystems that provide several important ecosystem services, including biodiversity, water regulation and purification, and climate regulation. Wetlands in the boreal landscape can have a great impact on streamflow behaviour, which is often used as an argument to restore and rewet wetland areas. A way of investigating the streamflow characteristics is with hydrological signatures. This study is complementary to previous studies and has the aim to investigate whether the extent of wetland cover in the catchment area has an effect on the hydrological low flow characteristic. A selection based on predefined criteria resulted in 75 catchments with 20 years of continuous streamflow data from 2001 to 2020. The analysis was done on three datasets: annual data, seasonal data and five catchment clusters. Correlations between wetland cover and landcover types and meteorological variables were detected using Kendall’s Tau correlation test. The found correlations were then further investigated with multiple linear regression. The results of this study indicate that wetland cover could shorten the low flow duration and increase monthly low flows. The seasonal analysis showed that the influence from wetland cover varies across the seasons. In spring, wetland cover had an increasing effect on the low flow signatures, but a negative effect in summer. The influence of wetland cover in autumn increased the mean streamflow and also decreased the low flows. The effect of wetland cover was the least in winter. The cluster analysis did not show any significant influence from wetland cover in any of the five clusters.