429 research outputs found

    Early Mission Maneuver Operations for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

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    The Deep Space Climate Observatory mission launched on February 11, 2015, and inserted onto a transfer trajectory toward a Lissajous orbit around the Sun-Earth L1 libration point. This paper presents an overview of the baseline transfer orbit and early mission maneuver operations leading up to the start of nominal science orbit operations. In particular, the analysis and performance of the spacecraft insertion, mid-course correction maneuvers, and the deep-space Lissajous orbit insertion maneuvers are discussed, com-paring the baseline orbit with actual mission results and highlighting mission and operations constraints.

    Ecological and Social Factors Constrain Spatial and Temporal Opportunities for Mating in a Migratory Songbird

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    Many studies of sexual selection assume that individuals have equal mating opportunities and that differences in mating success result from variation in sexual traits. However, the inability of sexual traits to explain variation in male mating success suggests that other factors moderate the strength of sexual selection. Extrapair paternity is common in vertebrates and can contribute to variation in mating success and thus serves as a model for understanding the operation of sexual selection. We developed a spatially explicit, multifactor model of all possible female-male pairings to test the hypothesis that ecological (food availability) and social (breeding density, breeding distance, and the social mate's nest stage) factors influence an individual's opportunity for extrapair paternity in a socially monogamous bird, the black-throated blue warbler, Setophaga caerulescens. A male's probability of siring extrapair young decreased with increasing distance to females, breeding density, and food availability. Males on food-poor territories were more likely to sire extrapair young, and these offspring were produced farther from the male's territory relative to males on food-abundant territories. Moreover, males sired extrapair young mostly during their social mates' incubation stage, especially males on food-abundant territories. This study demonstrates how ecological and social conditions constrain the spatial and temporal opportunities for extrapair paternity that affect variation in mating success and the strength of sexual selection in socially monogamous species

    Microbial communities and bioactive compounds in marine sponges of the family Irciniidae-a review

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    Marine sponges harbour complex microbial communities of ecological and biotechnological importance. Here, we propose the application of the widespread sponge family Irciniidae as an appropriate model in microbiology and biochemistry research. Half a gram of one Irciniidae specimen hosts hundreds of bacterial species-the vast majority of which are difficult to cultivate-and dozens of fungal and archaeal species. The structure of these symbiont assemblages is shaped by the sponge host and is highly stable over space and time. Two types of quorum-sensing molecules have been detected in these animals, hinting at microbe-microbe and host-microbe signalling being important processes governing the dynamics of the Irciniidae holobiont. Irciniids are vulnerable to disease outbreaks, and concerns have emerged about their conservation in a changing climate. They are nevertheless amenable to mariculture and laboratory maintenance, being attractive targets for metabolite harvesting and experimental biology endeavours. Several bioactive terpenoids and polyketides have been retrieved from Irciniidae sponges, but the actual producer (host or symbiont) of these compounds has rarely been clarified. To tackle this, and further pertinent questions concerning the functioning, resilience and physiology of these organisms, truly multi-layered approaches integrating cutting-edge microbiology, biochemistry, genetics and zoology research are needed.Portuguese Foundation [PTDC/MAR/101431/2008, PTDC/BIA-MIC/3865/2012]; European Regional Development Fund (ERDF) through the Operational Competitiveness Programme (COMPETE); national funds through FCT (Foundation for Science and Technology) [PEst-C/MAR/LA0015/2011]; FCT [SFRH/BD/60873/2009]info:eu-repo/semantics/publishedVersio

    Factors associated with cardiovascular events in systemic lupus erythematosus in a monocentric cohort with up to 40 years of follow-up

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    OBJECTIVES: Systemic lupus erythematosus (SLE) is associated with an increased cardiovascular risk. Several traditional and disease-specific risk factors have been shown to correlate with the occurrence of cardiovascular events (CVE) in patients with SLE. However, results of previous studies are diverse. The objectives of this study were to report number, type and those factors associated with CVE in patients with SLE in a large, single-center, ethnically diverse cohort with a long follow-up duration. METHODS: Medical records of patients treated at the Lupus Clinic at University College London Hospital (UCLH) between 1979 and 2020 were retrospectively reviewed. Data about CVE, traditional cardiovascular risk factors, demographic and disease features, and treatment history were collected. Only patients with complete available information were included in the study. Regression analyses were performed to identify factors associated with CVE. RESULTS: Four hundred and nineteen patients were included in the study. Maximum follow-up length was 40 years. Seventy-one (17%) patients had at least one CVE. Multivariable analysis showed that only antiphospholipid antibody positivity (p-value<0.001) was associated with CVE. When analysing different types of CVE, antiphospholipid antibodies were specifically associated with both venous thromboembolic events (p-value<0.001) and cerebrovascular events (p-value=0.007). Dedicated subanalyses revealed that cumulative glucocorticoid dose (p-value=0.010) and a diagnosis of SLE before 2000 (p-value<0.001) were significantly associated with CVE. CONCLUSIONS: Cardiovascular disease is highly prevalent among patients with SLE and is associated with antiphospholipid antibodies, glucocorticoid therapy, and diagnosis before 2000

    Phenotypic and genotypic monitoring of Schistosoma mansoni in Tanzanian schoolchildren five years into a preventative chemotherapy national control programme

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    We conducted combined in vitro PZQ efficacy testing with population genetic analyses of S. mansoni collected from children from two schools in 2010, five years after the introduction of a National Control Programme. Children at one school had received four annual PZQ treatments and the other school had received two mass treatments in total. We compared genetic differentiation, indices of genetic diversity, and estimated adult worm burden from parasites collected in 2010 with samples collected in 2005 (before the control programme began) and in 2006 (six months after the first PZQ treatment). Using 2010 larval samples, we also compared the genetic similarity of those with high and low in vitro sensitivity to PZQ

    Warm Springs, Early Lay Dates, and Double Brooding in a North American Migratory Songbird, the Black-Throated Blue Warbler

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    Numerous studies have correlated the advancement of lay date in birds with warming climate trends, yet the fitness effects associated with this phenological response have been examined in only a small number of species. Most of these species–primarily insectivorous cavity nesters in Europe–exhibit fitness declines associated with increasing asynchrony with prey. Here, we use 25 years of demographic data, collected from 1986 to 2010, to examine the effects of spring temperature on breeding initiation date, double brooding, and annual fecundity in a Nearctic - Neotropical migratory songbird, the black-throated blue warbler (Setophaga caerulescens). Data were collected from birds breeding at the Hubbard Brook Experimental Forest, New Hampshire, USA, where long-term trends toward warmer springs have been recorded. We found that black-throated blue warblers initiated breeding earlier in warmer springs, that early breeders were more likely to attempt a second brood than those starting later in the season, and that double brooding and lay date were linked to higher annual fecundity. Accordingly, we found selection favored earlier breeding in most years. However, in contrast to studies of several other long-distance migratory species in Europe, this selection pressure was not stronger in warmer springs, indicating that these warblers were able to adjust mean lay date appropriately to substantial inter-annual variation in spring temperature. Our results suggest that this North American migratory songbird might not experience the same fecundity declines as songbirds that are unable to adjust their timing of breeding in pace with spring temperatures

    New Mexico 4-H Online Horse Bowl Tournament

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    Under COVID-19 public health order constraints, Extension professionals used readily available technology (e.g., Google Forms, Zoom, Facebook Live, and QuizBowl Pro) to conduct a traditional 4-H quiz bowl contest entirely in a virtual setting as an innovative means of offering positive youth development in a structured environment when most New Mexicans were homebound and unable to travel. Participation in the virtual contest was substantially greater than similar in-person contests in the preceding five-year period, and youth reported an increase in equine knowledge as well as life skill development

    White Light Demonstration of One Hundred Parts per Billion Irradiance Suppression in Air by New Starshade Occulters

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    A new mission concept for the direct imaging of exo-solar planets called the New Worlds Observer (NWO) has been proposed. The concept involves flying a meter-class space telescope in formation with a newly-conceived, specially-shaped, deployable star-occulting shade several meters across at a separation of some tens of thousands of kilometers. The telescope would make its observations from behind the starshade in a volume of high suppression of incident irradiance from the star around which planets orbit. The required level of irradiance suppression created by the starshade for an efficacious mission is of order 0.1 to 10 parts per billion in broadband light. This paper discusses the experimental setup developed to accurately measure the suppression ratio of irradiance produced at the null position behind candidate starshade forms to these levels. It also presents results of broadband measurements which demonstrated suppression levels of just under 100 parts per billion in air using the Sun as a light source. Analytical modeling of spatial irradiance distributions surrounding the null are presented and compared with photographs of irradiance captured in situ behind candidate starshades

    Firearms on College Campuses: Research Evidence nad Policy Implications

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    This report reviews the evidence surrounding the relationship between civilian gun carrying and violent crime and mass shootings and factors that are unique to public safety on college campuses. Policies removing restrictions on civilian gun carrying are based on claims or assumptions about civilian gun use, the impact of state Right-to-Carry (RTC) laws, and the nature of mass shootings that are not supported by or are contrary to the best available research. The incidence of civilian self-defensive gun use (SDGU) is difficult to discern as available data are based on self-report, and distinguishing aggressor from victim in interpersonal altercations can be highly subjective. Nonetheless, data from the National Crime Victimization Survey indicate that SDGU is relatively rare (about 102,000 self-reported incidents per year affecting 0.9% of all violent crime victimizations) and is no more effective in reducing victims' risk of injury than other victim responses to attempted violent crimes. Research led by John Lott, author of More Guns, Less Crime, suggesting that RTC laws prevent violent crime has important flaws that biased his findings. The most recent and rigorous research on RTC laws that corrects for these flaws consistently finds that RTC laws are associated with more violent crime. These findings may seem counterintuitive because concealed-carry permit holders have, as a group, low rates of criminal offending and must pass a background check to ensure that they do not have any condition, such as a felony conviction, that prohibits firearm ownership. But, in states with low standards for legal gun ownership, legal gun owners account for the majority of persons incarcerated for committing violent crimes with firearms

    Active Learning Pipeline for Brain Mapping in a High Performance Computing Environment

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    This paper describes a scalable active learning pipeline prototype for large-scale brain mapping that leverages high performance computing power. It enables high-throughput evaluation of algorithm results, which, after human review, are used for iterative machine learning model training. Image processing and machine learning are performed in a batch layer. Benchmark testing of image processing using pMATLAB shows that a 100×\times increase in throughput (10,000%) can be achieved while total processing time only increases by 9% on Xeon-G6 CPUs and by 22% on Xeon-E5 CPUs, indicating robust scalability. The images and algorithm results are provided through a serving layer to a browser-based user interface for interactive review. This pipeline has the potential to greatly reduce the manual annotation burden and improve the overall performance of machine learning-based brain mapping.Comment: 6 pages, 5 figures, submitted to IEEE HPEC 2020 proceeding
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