225 research outputs found

    In situ sounding of radiative flux profiles through the Arctic lower troposphere

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    In situ profiles and fixed-altitude time series of all four components of net radiation were obtained at Ny-Ålesund, Svalbard (78.9° N, 11.9° E), in the period May 04–21, 2015. Measurements were performed using adapted high-quality instrumentation classified as “secondary standard” carried by a tethered balloon system. Balloon-lifted measurements of albedo under clear-sky conditions demonstrate the local dependence on altitude and on the surface inhomogeneity of this parameter over coastal terrain of Ny-Ålesund. Depending on the surface composition within the sensor’s footprint near the coastline, the albedo over predominantly snow-covered surfaces was found to decrease to 0.548 and 0.452 at 494 m and 881 m altitude compared with 0.731 and 0.788 measured with near-surface references, respectively. Albedo profiles show an all-sky maximum at 150 m above surface level due to local surface inhomogeneity, and an averaged vertical change rate of − 0.040/100 up to 750 m aboveground level (clear sky) and − 0.034/100 m (overcast). Profiling of arctic low-level clouds reveals distinct vertical gradients in all radiative fluxes but longwave upward at the cloud top. Observed radiative cooling at the top of a partly dissolving stratus cloud with heating rates of − 40.4 to − 62.1 Kd−1 in subsequent observations is exemplified

    Urgences pédiatriques: les moyens permettant d'identifier et de limiter les complications et les conséquences lors d'un traumatisme crùnio-cérébral léger à modéré

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    Cette revue de littĂ©rature vise Ă  dĂ©terminer des outils validĂ©s permettant Ă  l’infirmiĂšre d’identifier des TCC lĂ©gers Ă  modĂ©rĂ©s Ă  risque de dĂ©velopper des complications et des consĂ©quences. La finalitĂ© de cette revue est d’amĂ©liorer la qualitĂ© des soins infirmiers dĂšs l’admission d’un enfant aux urgences pĂ©diatriques jusqu’à la rĂ©cupĂ©ration complĂšte de ses symptĂŽmes

    Développement d'un cadre mathématique pour une théorie sensorimotrice de l'expérience sensorielle

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    Many neurophysiological theories of sensory experience assume that experience is mysteriously generated by specific cortical mechanisms. Other approaches claim that data on sensory experience can be explained from the structure of the rules governing sensory changes produced by various motor actions. The goal of this thesis is to develop a mathematical framework enabling to grasp symetry properties of such rules. In the case of a simplified perceptual system, we show that such an approach leads to distinguish categories of perceptual contexts, and changes of such contexts that coincide with various data on sensory experience, notably on spatiality sensation and the structure of our judgments on color similarities.Plusieurs théories neurophysiologiques de l'expérience sensorielle supposent que l'expérience est une chose mystérieuse produite par des mécanismes corticaux spécifiques. D'autres approches prétendent expliquer le discours que nous tenons sur nos expériences sensorielles à partir de la structure de nos fonctionnements sensorimoteurs, en particulier à partir de la dépendance induites par nos différents systÚmes perceptifs entre nos commandes motrices et nos stimulations sensorielles. Le but de cette thÚse est de développer un cadre mathématique permettant d'appréhender certaines propriétés de symétries de ces dépendances. En considérant le cas d'un systÚme perceptif simplifié, nous montrons que cette approche conduit à distinguer différentes catégories de situations perceptives, et de changements de situations, qui coïncident avec diverses données sur notre expérience sensorielle, notamment sur la sensation de spatialité et sur la structure de nos jugements de similarité des couleurs

    Accuracy of the IMET sensor package in the subtropics

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    Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 26 (2009): 1867-1890, doi:10.1175/2009JTECHO667.1.The accuracies of the meteorological sensors (air temperature, relative humidity, barometric pressure, near-surface temperature, longwave and shortwave radiation, and wind speed and direction) that compose the Improved Meteorological (IMET) system used on buoys at long-term ocean time series sites known as ocean reference stations (ORS) are analyzed to determine their absolute error characteristics. The predicted errors are compared to in situ measurement discrepancies and other observations (direct flux shipboard sensors) to confirm the predictions. The meteorological errors are then propagated through bulk flux formulas and the Coupled Ocean–Atmosphere Response Experiment (COARE) algorithm to give predicted errors for the heat flux components, the freshwater flux, and the momentum flux. Absolute errors are presented for three frequency bands [instantaneous (1-min sampling), diurnal, and annual]. The absolute uncertainty in the annually averaged net heat flux is found to be 8 W m−2 for conditions similar to the current ORS deployments in the subtropics.Support for the buoy deployments and the analysis from the NOAA Climate Observation Program is greatly appreciated (Grants NA17RJ1223 and NA17RJ1224)

    Isolating viable ancient bacteria: what you put in is what you get out

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    Letter to the editorRaphael Eisenhofer, Alan Cooper, Laura S. Weyric

    Signatures of landscape and captivity in the gut microbiota of Southern Hairy-nosed Wombats (Lasiorhinus latifrons)

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    Background: Herbivorous mammals co-opt microbes to derive energy and nutrients from diets that are recalcitrant to host enzymes. Recent research has found that captive management—an important conservation tool for many species—can alter the gut microbiota of mammals. Such changes could negatively impact the ability of herbivorous mammals to derive energy from their native diets, and ultimately reduce host fitness. To date, nothing is known of how captivity influences the gut microbiota of the Southern Hairy-nosed Wombat (SHNW), a large herbivorous marsupial that inhabits South Australia. Here, using 16S rRNA gene sequencing, we characterized the faecal microbiota of SHNWs in captivity and from three wild populations, two from degraded habitats and one from an intact native grass habitat. Results: We found that captive SHNWs had gut microbiota that were compositionally different and less diverse compared to wild SHNWs. There were major differences in gut microbiota community membership between captive and wild animals, both in statistically significant changes in relative abundance of microbes, and in the presence/absence of microbes. We also observed differences in microbial composition between wild populations, with the largest difference associated with native vs. degraded habitat. Conclusions: These results suggest that captivity has a major impact on the gut microbiota of SHNWs, and that different wild populations harbour distinct microbial compositions. Such findings warrant further work to determine what impacts these changes have on the fitness of SHNWs, and whether they could be manipulated to improve future management of the species.Raphael Eisenhofer, Kristofer M. Helgen, and David Taggar

    Aerosol climate feedback due to decadal increases in Southern Hemisphere wind speeds

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    Observations indicate that the westerly jet in the Southern Hemisphere troposphere is accelerating. Using a global aerosol model we estimate that the increase in wind speed of 0.45 + /- 0.2 m s(-1) decade(-1) at 50-65 degrees S since the early 1980s caused a higher sea spray flux, resulting in an increase of cloud condensation nucleus concentrations of more than 85% in some regions, and of 22% on average between 50 and 65 degrees S. These fractional increases are similar in magnitude to the decreases over many northern hemisphere land areas due to changes in air pollution over the same period. The change in cloud drop concentrations causes an increase in cloud reflectivity and a summertime radiative forcing between at 50 and 65 degrees S comparable in magnitude but acting against that from greenhouse gas forcing over the same time period, and thus represents a substantial negative climate feedback. However, recovery of Antarctic ozone depletion in the next two decades will likely cause a fall in wind speeds, a decrease in cloud drop concentration and a correspondingly weaker cloud feedback

    Investigating the demographic history of Japan using ancient oral microbiota

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    While microbial communities in the human body (microbiota) are now commonly associated with health and disease in industrialised populations, we know very little about how these communities co-evolved and changed with humans throughout history and deep prehistory. We can now examine these communities by sequencing ancient DNA preserved within calcified dental plaque (calculus), providing insights into the origins of disease and their links to human history. Here, we examine ancient DNA preserved within dental calculus samples and their associations with two major cultural periods in Japan: the Jomon period hunter–gatherers approximately 3000 years before present (BP) and the Edo period agriculturalists 400–150 BP. We investigate how human oral microbiomes have changed in Japan through time and explore the presence of microorganisms associated with oral diseases (e.g. periodontal disease, dental caries) in ancient Japanese populations. Finally, we explore oral microbial strain diversity and its potential links to ancient demography in ancient Japan by performing phylogenomic analysis of a widely conserved oral species—Anaerolineaceae oral taxon 439. This research represents, to our knowledge, the first study of ancient oral microbiomes from Japan and demonstrates that the analysis of ancient dental calculus can provide key information about the origin of non-infectious disease and its deep roots with human demography. This article is part of the theme issue ‘Insights into health and disease from ancient biomolecules’.Raphael Eisenhofer, Hideaki Kanzawa-Kiriyama, Ken-ichi Shinoda and Laura S. Weyric

    Host reproductive cycle influences the pouch microbiota of wild southern hairy-nosed wombats (Lasiorhinus latifrons)

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    Background: Marsupials are born much earlier than placental mammals, with most crawling from the birth canal to the protective marsupium (pouch) to further their development. However, little is known about the microbiology of the pouch and how it changes throughout a marsupial's reproductive cycle. Here, using stringent controls, we characterized the microbial composition of multiple body sites from 26 wild Southern Hairy-nosed Wombats (SHNWs), including pouch samples from animals at different reproductive stages. Results: Using qPCR of the 16S rRNA gene we detected a microbial community in the SHNW pouch. We observed significant differences in microbial composition and diversity between the body sites tested, as well as between pouch samples from different reproductive stages. The pouches of reproductively active females had drastically lower microbial diversity (mean ASV richness 19 ± 8) compared to reproductively inactive females (mean ASV richness 941 ± 393) and were dominated by gram positive bacteria from the Actinobacteriota phylum (81.7-90.6%), with the dominant families classified as Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, and Dietziaceae. Three of the five most abundant sequences identified in reproductively active pouches had closest matches to microbes previously isolated from tammar wallaby pouches. Conclusions: This study represents the first contamination-controlled investigation into the marsupial pouch microbiota, and sets a rigorous framework for future pouch microbiota studies. Our results indicate that SHNW pouches contain communities of microorganisms that are substantially altered by the host reproductive cycle. We recommend further investigation into the roles that pouch microorganisms may play in marsupial reproductive health and joey survival.Sesilje Weiss, David Taggart, Ian Smith, Kristofer M. Helgen and Raphael Eisenhofe
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