1,178 research outputs found

    Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae

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    Physiological measurements of both stress and sex hormones are often used to estimate the consequences of natural or human-induced change in ecological studies of various animals. Different methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross-validated to ensure that they correlate. We directly compared faecal and plasma hormone measurements for the first time in a wild free-living species, the Adelie penguin (Pygoscelis adeliae). Blood and faecal samples were simultaneously collected from individual penguins for comparison and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher mean corticosterone concentrations than females, but the difference was only statistically significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males, perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma ‘snapshot’ concentration. Our data indicate that faecal sampling appears more suitable for assessing baseline hormone concentrations, whilst plasma sampling may best define immediate responses to environmental events. Consequently, future studies should ensure that they select the most appropriate matrix and method of hormone measurement to answer their research questions

    Does past unemployment experience explain the transition happiness gap?

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    The profound economic and political changes of the 1990s had detrimental social effects in many domains of life in post-socialist countries, including diminishing life expectancy and growing unhappiness. Despite economic improvements in the second decade of transition, research has documented that happiness lagged behind. We test whether past unemployment experience can explain this “transition happiness gap in the context of Ukraine”, a country with a painful delayed transition from planned to market economy. We analyze unique longitudinal data for the period 2003–2012. Current unemployment substantially reduces subjective wellbeing, and the effect is roughly 50% larger for men than for women. The effect of past unemployment is significant, but small in magnitude compared to the effect of current unemployment. However, it does correspond to around 8% of the ‘’transition happiness gap” found by Guriev and Melnikov (2017), suggesting that past unemployment experience can be considered as a partial explanation

    Janus: Launch of a NASA SmallSat Mission to Near-Earth Binary Asteroids

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    Janus is a two-spacecraft SmallSat mission to fly by two different pairs of binary near Earth asteroids, (175706) 1996 FG3 and (35107) 1991 VH. The two identical Janus spacecraft are scheduled to launch during a launch period opening 1 August 2022 as secondary payloads with the NASA Psyche mission, on a SpaceX Falcon Heavy launch vehicle. Janus is led by principal investigator Dr. Dan Scheeres at the University of Colorado Boulder and managed, built, and operated by Lockheed Martin. These planetary SmallSats share many deep space challenges similar to larger missions: Janus must execute deep space maneuvers to achieve hundreds of meters per second ΔV to reach its destinations, close a telecommunication link at ranges up to 2.4 AU, autonomously manage a several-month-long telecommunications blackout during solar conjunction, operate at a maximum Sun range of 1.62 AU, and survive for approximately four years in interplanetary space before encountering their target asteroids. During the encounters, the spacecraft will return high resolution visible and infra-red images of the asteroids. In getting Janus to the pad, the implementation team successfully managed an aggressive mission schedule despite COVID-19 related supply chain impacts and work environments, all while remaining on target for the SIMPLEx-2 cost cap. Janus is a pathfinder for achievable and affordable SmallSat science missions and demonstrates the valuable partnership between an experienced deep space mission engineering team, the SmallSat commercial component industry, and a forward- looking NASA model for Class-D science missions

    Effects of an open-label pilot study with high-dose EPA/DHA concentrates on plasma phospholipids and behavior in children with attention deficit hyperactivity disorder

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    <p>Abstract</p> <p>Background</p> <p>Attention deficit hyperactivity disorder (ADHD) is the most common neurological condition in children. This pilot study evaluated the effects of high-dose eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on the isolated plasma phospholipids and behavior in children with ADHD (primarily inattentive subtype and combined subtype).</p> <p>Methods</p> <p>Nine children were initially supplemented with 16.2 g EPA/DHA concentrates per day. The dosage was adjusted dependent on the ratio of arachidonic acid (AA) to EPA in the isolated plasma phospholipids at four weeks to reach a level normally found in the Japanese population.</p> <p>Results</p> <p>At the end of the eight-week study, supplementation resulted in significant increases in EPA and DHA, as well as a significant reduction in the AA:EPA ratio (20.78 ± 5.26 to 5.95 ± 7.35, p < 0.01). A psychiatrist (blind to supplement compliance or dosage modifications) reported significant improvements in behavior (inattention, hyperactivity, oppositional/defiant behavior, and conduct disorder). There was also a significant correlation between the reduction in the AA:EPA ratio and global severity of illness scores.</p> <p>Conclusion</p> <p>The findings of this small pilot study suggest supplementation with high-dose EPA/DHA concentrates may improve behavior in children with ADHD.</p

    Correlations between life-detection techniques and implications for sampling site selection in planetary analog missions

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    We conducted an analog sampling expedition under simulated mission constraints to areas dominated by basaltic tephra of the Eldfell and Fimmvörðuháls lava fields (Iceland). Sites were selected to be “homogeneous” at a coarse remote sensing resolution (10–100 m) in apparent color, morphology, moisture, and grain size, with best-effort realism in numbers of locations and replicates. Three different biomarker assays (counting of nucleic-acid-stained cells via fluorescent microscopy, a luciferin/luciferase assay for adenosine triphosphate, and quantitative polymerase chain reaction (qPCR) to detect DNA associated with bacteria, archaea, and fungi) were characterized at four nested spatial scales (1 m, 10 m, 100 m, and >1 km) by using five common metrics for sample site representativeness (sample mean variance, group F tests, pairwise t tests, and the distribution-free rank sum H and u tests). Correlations between all assays were characterized with Spearman's rank test. The bioluminescence assay showed the most variance across the sites, followed by qPCR for bacterial and archaeal DNA; these results could not be considered representative at the finest resolution tested (1 m). Cell concentration and fungal DNA also had significant local variation, but they were homogeneous over scales of >1 km. These results show that the selection of life detection assays and the number, distribution, and location of sampling sites in a low biomass environment with limited a priori characterization can yield both contrasting and complementary results, and that their interdependence must be given due consideration to maximize science return in future biomarker sampling expeditions
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