64 research outputs found
Bat Occupancy Estimates and Species Richness at Cache River National Wildlife Refuge
Six bat species of special concern, threatened or endangered, may occur in one of Arkansas’ largest bottomland hardwood forests, the Cache River National Wildlife Refuge (CRNWR). However, inventory of bat species throughout the refuge has been lacking and management plans may not be adequate in promoting bat conservation. The objectives of this study were to inventory bat species in the CRNWR, and determine bat-habitat associations via occupancy estimates. From May–August 2014 and 2015, we mist-netted from sunset for 5 hours. We also deployed bioacoustic devices throughout 5 habitat types (cypress-tupelo [dominantly Taxodium distichum and Nyssa aquatica], emergent wetland, mature forest, hardwood reforestation, and managed hardwood). Mist-netting yielded 460 bat captures with Rafinesque’s big-eared bats (Corynorhinus rafinesquii; n = 156) being the most common capture, followed by eastern red bats (Lasiurus borealis; n = 104), southeastern myotis (Myotis austroriparius; n = 91), evening bats (Nycticeius humeralis; n = 58), tri-colored bats (Perimyotis subflavus; n = 54), and a big-brown bat (Eptesicus fuscus; n = 1). Based on 3,896 calls identified with 85% certainty, evening bats and rarer big-brown bats tended to occupy managed hardwood forests more than any other habitat (occupancy probabilities ± SE: Ψ = 0.75 ± 0.13 and 0.38 ± 0.19, respectively). Tri-colored bats tended to be more present in mature forest habitats (Ψ = 0.91 ± 0.09), and Myotis species tended to have highest occupancy rates in cypress-tupelo stands (Ψ = 0.59 ± 0.15). Not all species were detected with both methods. Thus, we encourage future studies to combine mist-netting and acoustic surveying methods to minimize bias in species presence estimate. This would ensure management practices that would benefit all present species
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Sibling Aggression, Feeding Rates, and Hatch Rank of Nestling Red-Shouldered Hawks (Buteo lineatus)
Article describes how, in many raptor species, hatching asynchrony results in a size hierarchy among nestlings, which may facilitate brood reduction by means of sibling aggression-induced mortality, especially in times of low food resources. The authors studied the influence of hatch rank, brood size, and brood age on aggression and feeding rates among Red-shouldered Hawk (Buteo lineatus) nestlings in suburban southwestern Ohio
Expansion of Regulatory T Cells in Patients with Langerhans Cell Histiocytosis
Frederic Geissmann and colleagues find that Langerhans cell accumulation in Langerhans cell histiocytosis results from survival rather than uncontrolled proliferation, and is associated with the expansion of regulatory T cells
Amplification of a Zygosaccharomyces bailii DNA Segment in Wine Yeast Genomes by Extrachromosomal Circular DNA Formation
We recently described the presence of large chromosomal segments resulting from independent horizontal gene transfer (HGT) events in the genome of Saccharomyces cerevisiae strains, mostly of wine origin. We report here evidence for the amplification of one of these segments, a 17 kb DNA segment from Zygosaccharomyces bailii, in the genome of S. cerevisiae strains. The copy number, organization and location of this region differ considerably between strains, indicating that the insertions are independent and that they are post-HGT events. We identified eight different forms in 28 S. cerevisiae strains, mostly of wine origin, with up to four different copies in a single strain. The organization of these forms and the identification of an autonomously replicating sequence functional in S. cerevisiae, strongly suggest that an extrachromosomal circular DNA (eccDNA) molecule serves as an intermediate in the amplification of the Z. bailii region in yeast genomes. We found little or no sequence similarity at the breakpoint regions, suggesting that the insertions may be mediated by nonhomologous recombination. The diversity between these regions in S. cerevisiae represents roughly one third the divergence among the genomes of wine strains, which confirms the recent origin of this event, posterior to the start of wine strain expansion. This is the first report of a circle-based mechanism for the expansion of a DNA segment, mediated by nonhomologous recombination, in natural yeast populations
Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.
RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)
INFLUENCE DES CHANGEMENTS CLIMATIQUES ET DES PÊCHERIES INDUSTRIELLES SUR LA DYNAMIQUE DES POPULATIONS D'ALBATROS DE L'OCEAN AUSTRAL
Les albatros étant des espèces menacées d'extinction, j'ai choisi de commencer cette introduction par un état des lieux général de la perte de biodiversité actuelle et d'en exposer les principaux facteurs. Par la suite, j'exposerai les mécanismes sous-jacents à la dynamique des populations. Enfin, le contexte particulier de l'écosystème marin dans lequel vivent les albatros sera abordé pour définir la problématique et les objectifs de cette thèse
Influence des changements climatiques et des pêcheries industrielles sur la dynamique des populations d'albatros de l'océan austral
Cette thèse s inscrit dans le contexte des changements globaux et du rythme accéléré d extinction des espèces. Le but est de quantifier l impact relatif des fluctuations climatiques et des activités humaines sur la démographie des populations. En particulier, les pêcheries industrielles font accidentellement, chaque année, des centaines de milliers de victimes parmi les oiseaux marins, notamment les albatros. Les réponses démographiques de quatre espèces d albatros menacés de l océan Austral (albatros à sourcils noirs, à bec jaune, fuligineux à dos sombre et grand albatros) sont comparées dans cette étude. Le succès reproducteur des quatre espèces a répondu de manière très contrastée aux anomalies climatiques selon la zone d alimentation (subtropical, sub-Antarctique) et la saison (reproduction, hors-reproduction). La survie de toutes ces espèces a été canalisée contre les variations climatiques mais fortement affectée par les pêcheries palangrières au thon rouge du Sud sauf pour l albatros à bec jaune dont le déclin serait majoritairement dû à la présence du choléra aviaire, cause d une forte mortalité des jeunes poussins. Les pêcheries semblent avoir un impact plus important que les changements climatiques mais les interactions des effets climatiques et des pêcheries sont complexes. En outre, le réchauffement prédit pour la fin du 21ème siècle annonce la croissance de la population d albatros à sourcils noirs de Kerguelen, à la condition que l effort de pêche n augmente pas tandis que celle des albatros fuligineux à dos sombre continuerait son déclin même dans le cas d un arrêt de la pêche. Il paraît donc nécessaire de prédire les conséquences futures du réchauffement et des activités humaines sur des espèces menacées comme les albatros.PARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF
La Qualité au 21ème siècle : vers le management de la confiance
Aborde le problème de la qualité selon trois perspectives : analyse la version 2000 de la norme ISO 9001 et la certification d'engagements de service ; la diffusion sectorielle de la démarche qualité dans la fonction publique et les professions juridiques ; approche traditionnelle de la qualité et les technologies de l'information et de la communication.ou
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Summary of random-effect model selection for (a) hatching success, (b) hatchability, and (c) fledging success of Eastern bluebirds and Carolina chickadees at the species and species-region levels. No fixed terms were included. Though the model with nest location was not always the most parsimonious, we included this random variable in all our models for consistency across analyses. Models are presented with corresponding k (number of parameters), AIC (Akaike’s Information Criterion), ΔAIC (difference in AIC between given model and lowest AIC model), and wi (model weight) values. (DOCX)</p
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