31325 research outputs found
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The Best of Two Worlds: Using Stacked Generalisation for Integrating Expert Range Maps in Species Distribution Models
No full textAim: Species distribution models (SDMs) are powerful tools for assessing suitable habitats across large areas and at fine spatial resolution. Yet, the usefulness of SDMs for mapping species' realised distributions is often limited since data biases or missing information on dispersal barriers or biotic interactions hinder them from accurately delineating species' range limits. One way to overcome this limitation is to integrate SDMs with expert range maps, which provide coarse‐scale information on the extent of species' ranges and thereby range limits that are complementary to information offered by SDMs. Innovation: Here, we propose a new approach for integrating expert range maps in SDMs based on an ensemble method called stacked generalisation. Specifically, our approach relies on training a meta‐learner regression model using predictions from one or more SDM algorithms alongside the distance of training points to expert‐defined ranges as predictor variables. We demonstrate our approach with an occurrence dataset for 49 bat species covering four biodiversity hotspots in the Eastern Mediterranean, Western Asia and Central Asia. Main Conclusions: Our approach offers a flexible method to integrate expert range maps with any combination of SDM modelling algorithms, thus facilitating the use of algorithm ensembles. In addition, it provides a novel, data‐driven way to account for uncertainty in expert‐defined ranges not requiring prior knowledge about their accuracy, which is often lacking. Integrating expert range maps into SDMs for bats resulted in more realistic predictions of distribution patterns that showed narrower niche breadths and smaller range overlaps between species compared to traditional SDMs. Our approach holds promise to improve assessments of species distributions, while our work highlights the overlooked potential of stacked generalisation as an ensemble method in species distribution modelling.Istanbul Teknik Üniversitesi http://dx.doi.org/10.13039/501100007504Leibniz Association http://dx.doi.org/10.13039/501100001664Peer Reviewe
A biomathematical model of SARS-CoV-2 in Syrian hamsters
No full textWhen infected with SARS-CoV-2, Syrian hamsters (Mesocricetus auratus) develop moderate disease severity presenting key features of human COVID-19. We here develop a biomathematical model of the disease course by translating known biological mechanisms of virus-host interactions and immune responses into ordinary differential equations. We explicitly describe the dynamics of virus population, affected alveolar epithelial cells, and involved relevant immune cells comprising for example CD4+ T cells, CD8+ T cells, macrophages, natural killer cells and B cells. We also describe the humoral response dynamics of neutralising antibodies and major regulatory cytokines including CCL8 and CXCL10. The model is developed and parametrized based on experimental data collected at days 2, 3, 5, and 14 post infection. Pulmonary cell composition and their transcriptional profiles were obtained by lung single-cell RNA (scRNA) sequencing analysis. Parametrization of the model resulted in a good agreement of model and data. The model can be used to predict, for example, the time course of the virus population, immune cell dynamics, antibody production and regeneration of alveolar cells for different therapy scenarios or after multiple-infection events. We aim to translate this model to the human situation in the future.Open Access funding enabled and organized by Projekt DEAL.Universität Leipzig (1039)Peer Reviewe
Syzygies of secant varieties of curves of genus 2
No full textEin, Niu and Park showed in [6] that if the degree of the line bundle L on a curve of genus g is at least 2g+2k+1, the k-th secant variety of the curve via the embedding defined by the complete linear system of L is normal, projectively normal and arithmetically Cohen-Macaulay, and they also proved some vanishing of the Betti diagrams. However, the length of the linear strand of weight k+1 of the resolution of the secant variety Σk of a curve of g≥2 is still mysterious. In this paper we calculate the complete Betti diagrams of the secant varieties of curves of genus 2 using Boij-Söderberg theory. The main idea is to find the pure diagrams that contribute to the Betti diagram of the secant variety via calculating some special positions of the Betti diagram
Sport for young people in their leisure time against the background of social trends
No full textVor dem Hintergrund von gesellschaftlichen Trends, die sich mit der Scholarisierung von Freizeit, Versportung jugendlicher Körper und Fitnesssport als neuem Sporttrend verschlagworten lassen, wird untersucht, welchen Stellenwert sportliche Aktivitäten in der Freizeit von Jugendlichen einnehmen und wie attraktiv der Sportverein im Vergleich zu anderen Sportsettings ist. Vor allem werden zeitliche Veränderungen in den Blick genommen. Zurückgegriffen wird auf Daten einer bundesweit repräsentativen Jugendsportstudie, die im Sommer 2023 als Online-Umfrage mit 1978 13- bis 17-Jährigen im Rahmen des Move-For-Health-Projekts (MFH) durchgeführt wurde. Die MFH-Daten werden mit der 2012 durchgeführten Studie „Jugend und Sport – Online“ verglichen, die Daten einer Zufallstichprobe von 1662 Altersgleichen enthält. Als Ergebnisse lassen sich festhalten: „Sportmachen“ nimmt nach wie vor einen großen Stellenwert bei Jugendlichen ein. 60 % der Befragten geben an, regelmäßig sportlich aktiv zu sein. Etwa 42 % der Jugendlichen sind in einem Sportverein aktiv, 13 % nutzen kommerzielle Sportangebote, 27 % gehen ihren Sportaktivitäten auch informell nach. Alles in allem weisen die Befunde darauf hin, dass die skizzierten gesellschaftlichen Trends mit einem veränderten Freizeit- und Sportverhalten von jungen Menschen einhergehen. Insbesondere die seit vielen Jahrzehnten postulierte These von der Versportung des Jugendalters scheint nach der Pandemie allerdings etwas ins Wanken geraten zu sein. Die Sportbeteiligung von Jugendlichen in der Freizeit ist deutlich gesunken. Inwieweit sich diese Entwicklungen fortsetzen oder kurzfristige Folgen der Pandemie sind, sollte weiter beobachtet werden.Against the backdrop of social trends that can be summarised as the scholasticisation of leisure time, the sportification of young bodies and fitness sports as a new sports trend, the importance of sporting activities in young people’s leisure time and how attractive the sports club is in comparison to other sports settings are examined. In particular, changes over time will be analysed. The study draws on data from a nationally representative youth sports study, which was conducted in summer 2023 as an online survey with 1978 13 to 17-year-olds as part of the Move For Health project (M4H). The M4H data is compared with the 2012 study “Youth and Sport—Online”, which contains data from a random sample of 1662 people of the same age. The results show that “doing sport” is still an important activity for young people. 60% of those surveyed stated that they were regularly active in sport. Around 42% of young people are active in a sports club, 13% use commercial sports facilities and 27% also engage in sports activities informally. All in all, the findings indicate that the social trends outlined go hand in hand with a change in young people’s sporting behaviour. In particular, however, the thesis of the sportification of adolescence, which has been postulated for many decades, seems to have faltered somewhat after the pandemic. Young people’s participation in sport in their leisure time has fallen significantly. The extent to which these developments will continue or are short-term consequences of the pandemic should be monitored further.Open Access funding enabled and organized by Projekt DEAL.Humboldt-Universität zu Berlin (1034)Peer Reviewe
Meditation expertise influences response bias and prestimulus alpha activity in the somatosensory signal detection task
No full textThis study investigates the proposed mechanism of mindfulness, its impact on body awareness and interoception, and its potential benefits for mental and physical health. Using psychophysical assessments, we compared 31 expert meditators with 33 matched controls (non‐meditators who engage in regular reading, more than 5 h per week) in terms of somatosensory accuracy with a somatosensory signal detection task (SSDT) and interoceptive sensibility via self‐report measures. We hypothesized that meditators would demonstrate superior somatosensory accuracy, indicative of heightened body awareness, potentially linked to increased alpha modulation in the somatosensory cortex, as observed via electroencephalography (EEG). In the SSDT, participants attempted to detect near‐threshold tactile stimuli presented with a non‐informative light in half of the trials. Contrary to our expectations, the findings showed that meditators had a lower decision threshold rather than higher accuracy. EEG results corroborated earlier research, indicating reduced prestimulus alpha power in meditators, suggesting enhanced alpha modulation. Furthermore, a trial‐by‐trial analysis revealed a negative correlation between prestimulus alpha activity and tactile perception. Compared to controls, meditators also reported greater interoceptive sensibility, less emotional suppression, and fewer difficulties in describing feelings. These findings may imply that enhanced tactile perception is associated with lower prestimulus alpha activity by reducing sensory filtering in the somatosensory cortex, thus increasing response rates without necessarily improving accuracy among meditators.Einstein Center for Neurosciences Berlin http://dx.doi.org/10.13039/501100023564Peer Reviewe
Telemedicine-based exercise intervention in cancer survivors: a non-randomized controlled trial
No full textCancer survivors (CS) often experience treatment-related side effects, such as fatigue, and have reduced physical function. Regular physical activity has been demonstrated to reduce these symptoms and improve cardiopulmonary fitness. Digital solutions are needed to optimize exercise options for CS in aftercare, especially given the significant limitations during the Covid-19 pandemic. This two-armed, non-randomized, controlled intervention study for CS aims to investigate whether a telemedicine-based exercise intervention is as effective as the current standard of care for oncological exercise therapy in aftercare. Patients in the intervention group (n = 61) performed a telemedicine-based exercise program (TE) and patients in the control group (n = 31) participated in an existing rehabilitation sports group (RG) over a six-month intervention period. The primary outcome was cardiopulmonary fitness measured by VO2peak; secondary outcomes included quality of life (QoL), fatigue, and physical activity. A non-inferiority analysis was performed with a predefined non-inferiority margin for relative VO2peak of -1.50 ml/min/kg. Although TE demonstrated a slight advantage in relative VO2peak compared to RG (adjusted mean difference of 0.55 ml/min/kg [95% CI: -2.74; 3.84]), the non-inferiority was not statistically significant. Nevertheless, the implementation of a telemedicine-based exercise intervention indicates that individual patients respond well to this type of exercise program and benefit from the intervention, particularly in terms of QoL. Finding an individualized program for each cancer survivor is the overarching goal. A telemedicine-based exercise intervention may be a promising option, particularly for younger patients.Peer Reviewe
Terahertz Resonant Emission by Optically Excited Infrared‐Active Shear Phonons in KY(MoO4)2
No full textThe generation of monochromatic electromagnetic radiation in the terahertz (THz) frequency range has remained a challenging task for many decades. Here, the emission of monochromatic sub‐THz radiation by optical phonons in the dielectric material KY(MoO4)2 is demonstrated. The layered crystal structure of KY(MoO4)2 causes infrared‐active shear lattice vibrations to have energies below 3.7 meV, corresponding to frequencies lower than 900 GHz where solid‐state‐based monochromatic radiation sources are rare. Directly excited by a 5 ps long broadband THz pulse, infrared‐active optical vibrations in KY(MoO4)2 re‐emit narrowband sub‐THz radiation as a time‐varying dipole for tens of picoseconds, which is exceptionally long for oscillators with frequencies below 1 THz. Such a long coherent emission allows for the detection of more than 50 periods of radiation with frequencies of 568 and 860 GHz. The remarkably long decay time together with the chemical stability of the employed material suggests a variety of possible applications in THz technology.Peer Reviewe
Sketching the spatial disparities in heatwave trends by changing atmospheric teleconnections in the Northern Hemisphere
No full textPronounced spatial disparities in heatwave trends are bound up with a diversity of atmospheric signals with complex variations, including different phases and wavenumbers. However, assessing their relationships quantitatively remains a challenging problem. Here, we use a network-searching approach to identify the strengths of heatwave-related atmospheric teleconnections (AT) with ERA5 reanalysis data. This way, we quantify the close links between heatwave intensity and AT in the Northern Hemisphere. Approximately half of the interannual variability of heatwaves is explained and nearly 80% of the zonally asymmetric trend signs are estimated correctly by the AT changes in the mid-latitudes. We also uncover that the likelihood of extremely hot summers has increased sharply by a factor of 4.5 after 2000 over areas with enhanced AT, but remained almost unchanged over the areas with attenuated AT. Furthermore, reproducing Eastern European heatwave trends among various models of the Coupled Model Intercomparison Project Phase 6 largely depends on the simulated Eurasian AT changes, highlighting the potentially significant impact of AT shifts on the simulation and projection of heatwaves
A compact tri-notched flexible UWB antenna based on an inkjet-printable and plasma-activated silver nano ink
No full textThe rapid development of ultrawideband (UWB) communication systems has resulted in increasing performance requirements for the antenna system. In addition to a wide bandwidth, fast propagation rates and compact dimensions, flexibility, wearability or portability are also desirable for UWB antennas, as are excellent notch characteristics. Although progress has been made in the development of flexible/wearable antennas desired notch properties are still rather limited. Moreover, most presently available flexible UWB antennas are fabricated using environmentally not attractive subtractive etching-based processes. The usage of facile additive sustainably inkjet printing processes also utilizing low temperature plasma-activated conductive inks is rarely reported. In addition, the currently used tri-notched flexible UWB antenna designs have a relatively large footprint, which poses difficulties when integrated into miniaturized and compact communication devices. In this work, a silver nano ink is used to fabricate the antenna via inkjet printing and an efficient plasma sintering procedure. For the targeted UWB applications miniaturized tri-notched flexible antenna is realized on a flexible polyethylene terephthalate (PET) substrate with a compact size of 17.6 mm × 16 mm × 0.12 mm. The antenna operates in the UWB frequency band (2.9–10.61 GHz), and can shield interferences from WiMAX (3.3–3.6 GHz), WLAN (5.150–5.825 GHz) and X-uplink (7.9–8.4 GHz) bands, as well as exhibits a certain of bendability. Three nested "C" slots of different sizes were adopted to achieve notch features. The simulation and test results demonstrate that the proposed antenna can generate signal radiation in the desired UWB frequency band while retaining the desired notch properties and having acceptable SAR values on-body, making it a viable candidate for usage in flexible or wearable communication transmission devices. The research provides a facile and highly efficient method for fabricating flexible/wearable UWB antennas, that is, the effective combination of inkjet printing processing, flexible substrates, low temperature-activated conductive ink and antenna structure design.Department of Education of Liaoning Provincehttp://dx.doi.org/10.13039/501100007620Liaoning Technical Universityhttp://dx.doi.org/10.13039/501100009015Peer Reviewe
Genome-Wide Association Study of Obsessive-Compulsive Symptoms including 33,943 individuals from the general population
No full textWhile 1–2% of individuals meet the criteria for a clinical diagnosis of obsessive-compulsive disorder (OCD), many more (~13–38%) experience subclinical obsessive-compulsive symptoms (OCS) during their life. To characterize the genetic underpinnings of OCS and its genetic relationship to OCD, we conducted the largest genome-wide association study (GWAS) meta-analysis of parent- or self-reported OCS to date (N = 33,943 with complete phenotypic and genome-wide data), combining the results from seven large-scale population-based cohorts from Sweden, the Netherlands, England, and Canada (including six twin cohorts and one cohort of unrelated individuals). We found no genome-wide significant associations at the single-nucleotide polymorphism (SNP) or gene-level, but a polygenic risk score (PRS) based on the OCD GWAS previously published by the Psychiatric Genetics Consortium (PGC-OCD) was significantly associated with OCS (Pfixed = 3.06 × 10−5). Also, one curated gene set (Mootha Gluconeogenesis) reached Bonferroni-corrected significance (Ngenes = 28, Beta = 0.79, SE = 0.16, Pbon = 0.008). Expression of genes in this set is high at sites of insulin mediated glucose disposal. Dysregulated insulin signaling in the etiology of OCS has been suggested by a previous study describing a genetic overlap of OCS with insulin signaling-related traits in children and adolescents. We report a SNP heritability of 4.1% (P = 0.0044) in the meta-analyzed GWAS, and heritability estimates based on the twin cohorts of 33–43%. Genetic correlation analysis showed that OCS were most strongly associated with OCD (rG = 0.72, p = 0.0007) among all tested psychiatric disorders (N = 11). Of all 97 tested phenotypes, 24 showed a significant genetic correlation with OCS, and 66 traits showed concordant directions of effect with OCS and OCD. OCS have a significant polygenic contribution and share genetic risk with diagnosed OCD, supporting the hypothesis that OCD represents the extreme end of widely distributed OCS in the population.Vetenskapsrådet (Swedish Research Council)https://doi.org/10.13039/501100004359U.S. Department of Health & Human Services | NIH | National Institute of Mental Health (NIMH)https://doi.org/10.13039/100000025U.S. Department of Health & Human Services | NIH | National Institute of Mental Health (NIMH)Nederlandse Organisatie voor Wetenschappelijk Onderzoek (Netherlands Organisation for Scientific Research)https://doi.org/10.13039/501100003246Foundation for the National Institutes of Health (Foundation for the National Institutes of Health, Inc.)https://doi.org/10.13039/100000009NTR is supported by multiple grants from the Netherlands Organizations for Scientific Research (NWO) and Medical Research (ZonMW): Netherlands Twin Registry Repository (NWO 480-15-001/674); Biobank-based integrative omics study (BIOS) funded by BBMRI-NL (NWO projects 184.021.007 and 184.033.111); the European Science Council (ERC) Genetics of Mental Illness (ERC Advanced, 230374, PI Boomsma); the Royal Netherlands Academy of Science Professor Award (PAH/6635) to D.I.B; the Genetic Association Information Network (GAIN) of the Foundation for the National Institutes of Health and Grand Opportunity grants 1RC2 MH089951).U.S. Department of Health & Human Services | NIH | National Institute of Mental Health (NIMH)Peer Reviewe