182 research outputs found

    Tiger Sharks Eat Songbirds: Reply

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    In response to our recent paper (Drymon et al. 2019), Yosef (2019) questions the mechanism proposed to explain interactions between tiger sharks (Galeocerdo cuvier) and migratory songbirds, while offering an alternative mechanism based on a single observation. We appreciate the comments from Yosef and the opportunity to respond

    Stickiness in a bouncer model: A slowing mechanism for Fermi acceleration

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    Some phase space transport properties for a conservative bouncer model are studied. The dynamics of the model is described by using a two-dimensional measure preserving mapping for the variables velocity and time. The system is characterized by a control parameter ϵ\epsilon and experiences a transition from integrable (ϵ=0\epsilon=0) to non integrable (ϵ≠0\epsilon\ne 0). For small values of ϵ\epsilon, the phase space shows a mixed structure where periodic islands, chaotic seas and invariant tori coexist. As the parameter ϵ\epsilon increases and reaches a critical value ϵc\epsilon_c all invariant tori are destroyed and the chaotic sea spreads over the phase space leading the particle to diffuse in velocity and experience Fermi acceleration (unlimited energy growth). During the dynamics the particle can be temporarily trapped near periodic and stable regions. We use the finite time Lyapunov exponent to visualize this effect. The survival probability was used to obtain some of the transport properties in the phase space. For large ϵ\epsilon, the survival probability decays exponentially when it turns into a slower decay as the control parameter ϵ\epsilon is reduced. The slower decay is related to trapping dynamics, slowing the Fermi Acceleration, i.e., unbounded growth of the velocityComment: 9 pages, 7 figure

    In-depth triacylglycerol profiling using MS3 Q-Trap mass spectrometry

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    Total triacylglycerol (TAG) level is a key clinical marker of metabolic and cardiovascular diseases. However, the roles of individual TAGs have not been thoroughly explored in part due to their extreme structural complexity. We present a targeted mass spectrometry-based method combining multiple reaction monitoring (MRM) and multiple stage mass spectrometry (MS3) for the comprehensive qualitative and semiquantitative profiling of TAGs. This method referred as TriP-MS3 – triacylglycerol profiling using MS3 – screens for more than 6,700 TAG species in a fully automated fashion. TriP-MS3 demonstrated excellent reproducibility (median interday CV ∼ 0.15) and linearity (median R2 = 0.978) and detected 285 individual TAG species in human plasma. The semiquantitative accuracy of the method was validated by comparison with a state-of-the-art reverse phase liquid chromatography (RPLC)-MS (R2 = 0.83), which is the most commonly used approach for TAGs profiling. Finally, we demonstrate the utility and the versatility of the method by characterizing the effects of a fatty acid desaturase inhibitor on TAG profiles in vitro and by profiling TAGs in Caenorhabditis elegans.Fil: Cabruja, Matias Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. University of Stanford; Estados UnidosFil: Priotti, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. University of California; Estados UnidosFil: Domizi, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. University of Stanford; Estados UnidosFil: Papsdorf, Katharina. University of Stanford; Estados UnidosFil: Kroetz, Deanna L.. University of California; Estados UnidosFil: Brunet, Anne. University of Stanford; Estados UnidosFil: Contrepois, Kévin. University of Stanford; Estados UnidosFil: Snyder, Michael P.. University of Stanford; Estados Unido

    Documentation of Atlantic Tarpon (Megalops atlanticus) Space Use and Move Persistence in the Northern Gulf of Mexico Facilitated by Angler Advocates

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    Atlantic tarpon (Megalops atlanticus, hereafter tarpon) are facing a multitude of stressors and are considered Vulnerable by the IUCN; however, significant gaps remain in our understanding of tarpon space use and movement. From 2018 to 2019, citizen scientists facilitated tagging of 23 tarpon with SPOT tags to examine space use and movement across the northern Gulf of Mexico. Movement-based kernel densities were used to estimate simplified biased random bridge-based utilization distributions and a joint move persistence model was used to estimate a behavioral index for each fish. Tarpon showed consistent east–west movement from the Alabama/Florida border to Louisiana, and utilization distributions were highest in the Mississippi River Delta. Move persistence was highest in Alabama and Mississippi and lowest in Louisiana. Our examination of tarpon space use and movement indicates that Louisiana is a critical, yet understudied, part of their range

    O DIALOGISMO NA ERA DIGITAL

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    Neste trabalho, propõem-se algumas reflexões sobre o dialogismo presente nacomunicação realizada pela internet. Para tanto, foram apresentados algunsexemplos de práticas discursivas encontradas em redes sociais contendo todaforma de discurso e o dialogismo como seu elemento constituinte. Para talproposta, fundamenta-se nas teorias de Mikhail Bakhtin, articuladas com algunsautores contemporâneos como Brait, Fiorin, dentre outros. Neste estudo, também,converge-se para a importância da educação na perspectiva dos letramentos noensino de linguagem

    Identification of a Genomic Region Between SLC29A1 and HSP90AB1 Associated With Risk of Bevacizumab-Induced Hypertension: CALGB 80405 (Alliance)

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    Purpose: Bevacizumab is a VEGF-specific angiogenesis inhibitor indicated as an adjunct to chemotherapy for the treatment of multiple cancers. Hypertension is commonly observed during bevacizumab treatment, and high-grade toxicity can limit therapy or lead to cardiovascular complications. The factors that contribute to interindividual variability in blood pressure rise during bevacizumab treatment are not well understood.Experimental Design: To identify genomic regions associated with bevacizumab-induced hypertension risk, sequencing of candidate genes and flanking regulatory regions was performed on 61 patients treated with bevacizumab (19 cases developed early-onset grade 3 hypertension and 42 controls had no reported hypertension in the first six cycles of treatment). SNP-based tests for common variant associations and gene-based tests for rare variant associations were performed in 174 candidate genes.Results: Four common variants in independent linkage disequilibrium blocks between SLC29A1 and HSP90AB1 were among the top associations. Validation in larger bevacizumab-treated cohorts supported association between rs9381299 with early grade 3+ hypertension (P = 0.01; OR, 2.4) and systolic blood pressure >180 mm Hg (P = 0.02; OR, 2.1). rs834576 was associated with early grade 3+ hypertension in CALGB 40502 (P = 0.03; OR, 2.9). These SNP regions are enriched for regulatory elements that may potentially increase gene expression. In vitro overexpression of SLC29A1 in human endothelial cells disrupted adenosine signaling and reduced nitric oxide levels that were further lowered upon bevacizumab exposure.Conclusions: The genomic region between SLC29A1 and HSP90AB1 and its role in regulating adenosine signaling are key targets for further investigation into the pathogenesis of bevacizumab-induced hypertension
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