895 research outputs found

    Measured electron contribution to Shuttle plasma environment: Abbreviated update

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    The differential energy spectra of electrons between 1 and 100 eV were measured by an electron spectrometer flown on an early shuttle. This energy range was scanned in 64 incremental steps with a resolution of 7%. The most striking feature that was observed throughout these spectra was a relatively flat distribution of the higher energy electrons out to 100 eV. This is in contrast to normal ambient spectra which consistently show a rapid decline in quantitative flux beyond 50 to 55 eV. The lower energy (1 to 2 eV) end of these spectra showed steep thermal trails comparable to normal ambient spectral structure. In general, daytime fluxes were significantly higher than those obtained during nighttime measurements. Quantitative flux excursions which may possibly be associated with thruster firing were frequently observed. Spectral structure suggestive of the N2 vibrational excitation energy loss mechanism was also seen in the data from some measurement periods. Examples of these spectra are shown and possible correlations are discussed

    Earthquake Arrival Association with Backprojection and Graph Theory

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    The association of seismic wave arrivals with causative earthquakes becomes progressively more challenging as arrival detection methods become more sensitive, and particularly when earthquake rates are high. For instance, seismic waves arriving across a monitoring network from several sources may overlap in time, false arrivals may be detected, and some arrivals may be of unknown phase (e.g., P- or S-waves). We propose an automated method to associate arrivals with earthquake sources and obtain source locations applicable to such situations. To do so we use a pattern detection metric based on the principle of backprojection to reveal candidate sources, followed by graph-theory-based clustering and an integer linear optimization routine to associate arrivals with the minimum number of sources necessary to explain the data. This method solves for all sources and phase assignments simultaneously, rather than in a sequential greedy procedure as is common in other association routines. We demonstrate our method on both synthetic and real data from the Integrated Plate Boundary Observatory Chile (IPOC) seismic network of northern Chile. For the synthetic tests we report results for cases with varying complexity, including rates of 500 earthquakes/day and 500 false arrivals/station/day, for which we measure true positive detection accuracy of > 95%. For the real data we develop a new catalog between January 1, 2010 - December 31, 2017 containing 817,548 earthquakes, with detection rates on average 279 earthquakes/day, and a magnitude-of-completion of ~M1.8. A subset of detections are identified as sources related to quarry and industrial site activity, and we also detect thousands of foreshocks and aftershocks of the April 1, 2014 Mw 8.2 Iquique earthquake. During the highest rates of aftershock activity, > 600 earthquakes/day are detected in the vicinity of the Iquique earthquake rupture zone

    Metamorphic Domain-Specific Languages: A Journey Into the Shapes of a Language

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    External or internal domain-specific languages (DSLs) or (fluent) APIs? Whoever you are -- a developer or a user of a DSL -- you usually have to choose your side; you should not! What about metamorphic DSLs that change their shape according to your needs? We report on our 4-years journey of providing the "right" support (in the domain of feature modeling), leading us to develop an external DSL, different shapes of an internal API, and maintain all these languages. A key insight is that there is no one-size-fits-all solution or no clear superiority of a solution compared to another. On the contrary, we found that it does make sense to continue the maintenance of an external and internal DSL. The vision that we foresee for the future of software languages is their ability to be self-adaptable to the most appropriate shape (including the corresponding integrated development environment) according to a particular usage or task. We call metamorphic DSL such a language, able to change from one shape to another shape

    Mitigating Covid-19 Infection Rates and Increasing Vaccination Rates for Children Ages 5-11: A Content Analysis of How Two Hospitals’ Use of Effective Social Media Engagement Helped to Influence a Healthier Public

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    The Covid-19 outbreak initiated an international public health crisis, altering our publics dependency on health organizations communication strategies and tactics. Immediate crisis communication and public health efforts were needed to mitigate panic and infectious disease across the globe. The digital marketing strategies utilized for social media began to reflect the value of accurate and timely information spread in correlation to a healthier targeted public for large health organizations. The significance of this thesis in the field of communications directly correlates to the health belief model, which is used to observe the motivation and decision-making processes that influence an individual’s choice to seek medical intervention. This Quantitative Analysis approach will use qualitative and quantitative research studying two out-of-state hospitals from leading health organizations and analyze their promotional success and failures concerning pediatric Covid-19 rates, specifically children ages 5-11. After analyzing the hospital\u27s social media engagement metrics, data comparisons will be drawn to establish a correlation between effective communication and a healthier, informed, and motivated public through increased engagement as a factor for these health outcomes. I will begin by analyzing three chosen social media platforms: Instagram, Facebook, and Twitter. My analysis will compare Children’s of Alabama with records of high pediatric Covid-19 infection and Boston Children’s Hospital with lower records of pediatric Covid-19 infection rates. This will lead to an informed analysis focusing on which hospital\u27s social media accounts are most engaging, resulting in their public being well-informed and motivated to act as a healthier public when reflected in their infection rates

    Virulence difference between the prototypic Schu S4 strain (A1a) and Francisella tularensisA1a, A1b, A2 and type B strains in a murine model of infection

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    BACKGROUND: The use of prototypic strains is common among laboratories studying infectious agents as it promotes consistency for data comparability among and between laboratories. Schu S(4) is the prototypic virulent strain of Francisella tularensis and has been used extensively as such over the past six decades. Studies have demonstrated virulence differences among the two clinically relevant subspecies of F. tularensis, tularensis (type A) and holarctica (type B) and more recently between type A subpopulations (A1a, A1b and A2). Schu S(4) belongs to the most virulent subspecies of F. tularensis, subspecies tularensis. METHODS: In this study, we investigated the relative virulence of Schu S(4) in comparison to A1a, A1b, A2 and type B strains using a temperature-based murine model of infection. Mice were inoculated intradermally and a hypothermic drop point was used as a surrogate for death. Survival curves and the length of temperature phases were compared for all infections. Bacterial burdens were also compared between the most virulent type A subpopulation, A1b, and Schu S(4) at drop point. RESULTS: Survival curve comparisons demonstrate that the Schu S(4) strain used in this study resembles the virulence of type B strains, and is significantly less virulent than all other type A (A1a, A1b and A2) strains tested. Additionally, when bacterial burdens were compared between mice infected with Schu S(4) or MA00-2987 (A1b) significantly higher burdens were present in the blood and spleen of mice infected with MA00-2987. CONCLUSIONS: The knowledge gained from using Schu S(4) as a prototypic virulent strain has unquestionably advanced the field of tularemia research. The findings of this study, however, indicate that careful consideration of F. tularensis strain selection must occur when the overall virulence of the strain used could impact the outcome and interpretation of results

    Inference and Evolutionary Analysis of Genome-Scale Regulatory Networks in Large Phylogenies

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    Changes in transcriptional regulatory networks can significantly contribute to species evolution and adaptation. However, identification of genome-scale regulatory networks is an open challenge, especially in non-model organisms. Here, we introduce multi-species regulatory network learning (MRTLE), a computational approach that uses phylogenetic structure, sequence-specific motifs, and transcriptomic data, to infer the regulatory networks in different species. Using simulated data from known networks and transcriptomic data from six divergent yeasts, we demonstrate that MRTLE predicts networks with greater accuracy than existing methods because it incorporates phylogenetic information. We used MRTLE to infer the structure of the transcriptional networks that control the osmotic stress responses of divergent, non-model yeast species and then validated our predictions experimentally. Interrogating these networks reveals that gene duplication promotes network divergence across evolution. Taken together, our approach facilitates study of regulatory network evolutionary dynamics across multiple poorly studied species. Keywords: regulatory networks; network inference; evolution of gene regulatory networks; evolution of stress response; yeast; probabilistic graphical model; phylogeny; comparative functional genomicsNational Science Foundation (U.S.) (Grant DBI-1350677)National Institutes of Health (U.S.) (Grant R01CA119176-01)National Institutes of Health (U.S.) (Grant DP1OD003958-01

    ‘Priming’ exercise and O2 uptake kinetics during treadmill running

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    We tested the hypothesis that priming exercise would speed kinetics during treadmill running. Eight subjects completed a square-wave protocol, involving two bouts of treadmill running at 70% of the difference between the running speeds at lactate threshold (LT) and max, separated by 6-min of walking at 4 km h−1, on two occasions. Oxygen uptake was measured breath-by-breath and subsequently modelled using non-linear regression techniques. Heart rate and blood lactate concentration were significantly elevated prior to the second exercise bout compared to the first. However, kinetics was not significantly different between the first and second exercise bouts (mean ± S.D., phase II time constant, Bout 1: 16 ± 3 s vs. Bout 2: 16 ± 4 s; slow component amplitude, Bout 1: 0.24 ± 0.10 L min−1vs. Bout 2: 0.20 ± 0.12 L min−1; mean response time, Bout 1: 34 ± 4 s vs. Bout 2: 34 ± 6 s; P > 0.05 for all comparisons). These results indicate that, contrary to previous findings with other exercise modalities, priming exercise does not alter kinetics during high-intensity treadmill running, at least in physically active young subjects. We speculate that the relatively fast kinetics and the relatively small slow component in the control (‘un-primed’) condition negated any enhancement of kinetics by priming exercise in this exercise modality
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