30 research outputs found

    The field high-amplitude SX Phe variable BL Cam: results from a multisite photometric campaign. II. Evidence of a binary - possibly triple - system

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    Short-period high-amplitude pulsating stars of Population I (δ\delta Sct stars) and II (SX Phe variables) exist in the lower part of the classical (Cepheid) instability strip. Most of them have very simple pulsational behaviours, only one or two radial modes being excited. Nevertheless, BL Cam is a unique object among them, being an extreme metal-deficient field high-amplitude SX Phe variable with a large number of frequencies. Based on a frequency analysis, a pulsational interpretation was previously given. aims heading (mandatory) We attempt to interpret the long-term behaviour of the residuals that were not taken into account in the previous Observed-Calculated (O-C) short-term analyses. methods heading (mandatory) An investigation of the O-C times has been carried out, using a data set based on the previous published times of light maxima, largely enriched by those obtained during an intensive multisite photometric campaign of BL Cam lasting several months. results heading (mandatory) In addition to a positive (161 ±\pm 3) x 109^{-9} yr1^{-1} secular relative increase in the main pulsation period of BL Cam, we detected in the O-C data short- (144.2 d) and long-term (\sim 3400 d) variations, both incompatible with a scenario of stellar evolution. conclusions heading (mandatory) Interpreted as a light travel-time effect, the short-term O-C variation is indicative of a massive stellar component (0.46 to 1 M_{\sun}) with a short period orbit (144.2 d), within a distance of 0.7 AU from the primary. More observations are needed to confirm the long-term O-C variations: if they were also to be caused by a light travel-time effect, they could be interpreted in terms of a third component, in this case probably a brown dwarf star (\geq 0.03 \ M_{\sun}), orbiting in \sim 3400 d at a distance of 4.5 AU from the primary.Comment: 7 pages, 5 figures, accepted for publication in A&

    Enhancing discovery of genetic variants for posttraumatic stress disorder through integration of quantitative phenotypes and trauma exposure information

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    Background Posttraumatic stress disorder (PTSD) is heritable and a potential consequence of exposure to traumatic stress. Evidence suggests that a quantitative approach to PTSD phenotype measurement and incorporation of lifetime trauma exposure (LTE) information could enhance the discovery power of PTSD genome-wide association studies (GWASs). Methods A GWAS on PTSD symptoms was performed in 51 cohorts followed by a fixed-effects meta-analysis (N = 182,199 European ancestry participants). A GWAS of LTE burden was performed in the UK Biobank cohort (N = 132,988). Genetic correlations were evaluated with linkage disequilibrium score regression. Multivariate analysis was performed using Multi-Trait Analysis of GWAS. Functional mapping and annotation of leading loci was performed with FUMA. Replication was evaluated using the Million Veteran Program GWAS of PTSD total symptoms. Results GWASs of PTSD symptoms and LTE burden identified 5 and 6 independent genome-wide significant loci, respectively. There was a 72% genetic correlation between PTSD and LTE. PTSD and LTE showed largely similar patterns of genetic correlation with other traits, albeit with some distinctions. Adjusting PTSD for LTE reduced PTSD heritability by 31%. Multivariate analysis of PTSD and LTE increased the effective sample size of the PTSD GWAS by 20% and identified 4 additional loci. Four of these 9 PTSD loci were independently replicated in the Million Veteran Program. Conclusions Through using a quantitative trait measure of PTSD, we identified novel risk loci not previously identified using prior case-control analyses. PTSD and LTE have a high genetic overlap that can be leveraged to increase discovery power through multivariate methods

    Potential causal association between gut microbiome and posttraumatic stress disorder

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    Background: The causal effects of gut microbiome and the development of posttraumatic stress disorder (PTSD) are still unknown. This study aimed to clarify their potential causal association using mendelian randomization (MR). Methods: The summary-level statistics for gut microbiome were retrieved from a genome-wide association study (GWAS) of the MiBioGen consortium. As to PTSD, the Freeze 2 datasets were originated from the Psychiatric Genomics Consortium Posttraumatic Stress Disorder Working Group (PGC-PTSD), and the replicated datasets were obtained from FinnGen consortium. Single nucleotide polymorphisms meeting MR assumptions were selected as instrumental variables. The inverse variance weighting (IVW) method was employed as the main approach, supplemented by sensitivity analyses to evaluate potential pleiotropy and heterogeneity and ensure the robustness of the MR results. We also performed reverse MR analyses to explore PTSD’s causal effects on the relative abundances of specific features of the gut microbiome. Results: In Freeze 2 datasets from PGC-PTSD, eight bacterial traits revealed a potential causal association between gut microbiome and PTSD (IVW, all P < 0.05). In addition, Genus.Dorea and genus.Sellimonas were replicated in FinnGen datasets, in which eight bacterial traits revealed a potential causal association between gut microbiome and the occurrence of PTSD. The heterogeneity and pleiotropy analyses further supported the robustness of the IVW findings, providing additional evidence for their reliability. Conclusion: Our study provides the potential causal impact of gut microbiomes on the development of PTSD, shedding new light on the understanding of the dysfunctional gut-brain axis in this disorder. Our findings present novel evidence and call for investigations to confirm the association between their links, as well as to illuminate the underlying mechanisms

    International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci

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    The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5–20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson’s disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations. © 2019, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply

    Оптимизация конструкции захвата для детали «Барабан»

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    Грузозахватные приспособления обычно применяются при производстве работ по подъему и перемещению грузов с применением грузоподъемных машин. Использование приспособлений позволяет реализовать максимальное удобство и безопасность производственного процесса. Грузозахватные приспособления конструируются для определенного этапа технологического процесса, для конкретного изделия. При проектировании таких приспособлений необходимо учитывать основные показатели оптимальности конструкции: прочность, надежность, простота, удобство и безопасность при эксплуатации, эргономичность. Кроме того, нужно стремиться к наименьшей массе и, соответственно, металлоемкости захвата. Конструкция грузозахватного приспособления, в основном, будет зависеть от назначенных технологом поверхностей, за которые можно крепиться и от максимальной высоты подъема крюка крана. В статье описана задача по конструированию захвата для детали «Барабан¬ в новом технологическом процессе. Рассмотрена конструкция существующего захвата, взятого за прототип. Приведен анализ различных вариантов конструктивных решений, созданных в процессе проектирования. Выбран вариант конструкции захвата, который в наибольшей степени соответствует требованиям технического задания. Конструкция этого модернизированного приспособления представляет собой захват с тремя лапами, удерживающими деталь, и подвес в виде траверсы. Разработанная конструкторская документация утверждена производством и отделом промышленной безопасности

    International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci

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    The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5–20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson’s disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations

    Integrated Forest Policy and Economics, An International Masters Program in Southeast Europe

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    In 2007, the first FOPER masters program on Integrated Forest Policy and Economics was offered jointly by the University of Belgrade, Faculty of Forestry and the University of Sarajevo, Faculty of Forestry and accredited by not only Bosnia‐Herzegovina and Serbia, but also Albania, Croatia and Macedonia. Twenty‐four students from these countries enrolled in the program and to date nineteen of them have successfully defended their master’s thesis. This innovative program was the first time that students from the former Yugoslavian countries came together in a joint educational setting. It was also the first time that faculty from the different universities collaborated in offering a single curriculum. This MSc program is part of a larger capacity building project in Southeast Europe focused on increasing research and education in both forest policy and economics, areas of weakness in recent decades and essential for current policy and practice. It is also in compliance with the new educational policy in Europe called ‘the Bologna Process’. In 2010, the second offering of the FOPER MSc program will begin in Sarajevo and continue in Belgrade as before. In addition to the common curriculum of study, the students will be integrated into multi‐country research projects that are lead by a collaborative group of faculty and researchers from the SEE region, Europe and potentially elsewhere for their thesis research. What is distinctive about this program is the effort to integrate the teaching of policy and economics. These topics are often separated – in theory and disciplinary organization as well as in teaching— leading students, researchers and policy makers to consider each as a separately functioning aspect of society. Nothing could be farther from actual practice and in the context of rapid political, economic and social transition in the SEE countries, this artificial divide is untenable when effective new policies and institutions are being created. From this disciplinary, pedagogical and practical commitment comes also a social and political commitment to address problems of relevance to the region, to prepare students for a social and political environment that is much different than their professors and families experienced, and to create a functioning science‐policy community that is capable of addressing the challenging issues of the times. This paper will address the origin and design of this new program, but will focus on the impact of this educational and research experience on the students, faculties and universities as well as prospects for the future in terms of education, research, management and policy. As part of a larger donor funded capacity building project, the FOPER MSc program precipitated numerous innovations in teaching method and style, modes of research organization, and recognition of the value of social science in natural resource and environmental policy making processes. In addition, new educational and research capacities resulted from this collaborative effort which can support the incorporation of a wider network of teachers and a more international body of students. These kinds of programs can offer an opportunity for US universities to cooperate with European partner programs so as to greatly expand the opportunities for students

    Stress-Induced Pathology and Accelerated Aging

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    Local forest governance assessed through Social Network Analysis: comparison of three case studies in Italy, Bosnia Herzegovina and Montenegro

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    In natural resources governance, there is a growing awareness on the importance of being able to manage multidimensional networks which involve a multitude of actors representing different levels (from local to international; vertical integration) and various (public and private) sectors (horizontal integration). The organizations which play key roles in local development based on forest resources need to involve actors of civil society in decision-making processes, and to form new networks of collaboration and information exchange. At local level, governance assessment systems seldom consider the analysis of networks as an instrument to better address policy making, and Social Network Analysis (SNA) is prominently used in descriptive studies. In our work, SNA tool has been applied in three case studies (protected forest areas, in Italy, Montenegro and Bosnia-Herzegovina). Indices, including network density and cliques analysis, typical of SNA, have been calculated as proxy indicators for evaluating key aspects of governance capacity (e.g. level of efficiency and participation). The snowball technique was applied to identify stakeholders, data were collected through face-to-face interviews in 2012 and 2013, and networks were graphically represented. Results show that SNA is important to assess the role of main actors and to evaluate the policy process in local forest governance
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