821 research outputs found

    A novel virus genome discovered in an extreme environment suggests recombination between unrelated groups of RNA and DNA viruses

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    <p>Abstract</p> <p>Background</p> <p>Viruses are known to be the most abundant organisms on earth, yet little is known about their collective origin and evolutionary history. With exceptionally high rates of genetic mutation and mosaicism, it is not currently possible to resolve deep evolutionary histories of the known major virus groups. Metagenomics offers a potential means of establishing a more comprehensive view of viral evolution as vast amounts of new sequence data becomes available for comparative analysis.</p> <p>Results</p> <p>Bioinformatic analysis of viral metagenomic sequences derived from a hot, acidic lake revealed a circular, putatively single-stranded DNA virus encoding a major capsid protein similar to those found only in single-stranded RNA viruses. The presence and circular configuration of the complete virus genome was confirmed by inverse PCR amplification from native DNA extracted from lake sediment. The virus genome appears to be the result of a RNA-DNA recombination event between two ostensibly unrelated virus groups. Environmental sequence databases were examined for homologous genes arranged in similar configurations and three similar putative virus genomes from marine environments were identified. This result indicates the existence of a widespread but previously undetected group of viruses.</p> <p>Conclusions</p> <p>This unique viral genome carries implications for theories of virus emergence and evolution, as no mechanism for interviral RNA-DNA recombination has yet been identified, and only scant evidence exists that genetic exchange occurs between such distinct virus lineages.</p> <p>Reviewers</p> <p>This article was reviewed by EK, MK (nominated by PF) and AM. For the full reviews, please go to the Reviewers' comments section.</p

    Torsion cycles as non-local magnetic sources in non-orientable spaces

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    Non-orientable spaces can appear to carry net magnetic charge, even in the absence of magnetic sources. It is shown that this effect can be understood as a physical manifestation of the existence of torsion cycles of codimension one in the homology of space.Comment: 17 pages, 4 figure

    Effects of nanoparticles on murine macrophages

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    Metallic nanoparticles are more and more widely used in an increasing number of applications. Consequently, they are more and more present in the environment, and the risk that they may represent for human health must be evaluated. This requires to increase our knowledge of the cellular responses to nanoparticles. In this context, macrophages appear as an attractive system. They play a major role in eliminating foreign matter, e.g. pathogens or infectious agents, by phagocytosis and inflammatory responses, and are thus highly likely to react to nanoparticles. We have decided to study their responses to nanoparticles by a combination of classical and wide-scope approaches such as proteomics. The long term goal of this study is the better understanding of the responses of macrophages to nanoparticles, and thus to help to assess their possible impact on human health. We chose as a model system bone marrow-derived macrophages and studied the effect of commonly used nanoparticles such as TiO2 and Cu. Classical responses of macrophage were characterized and proteomic approaches based on 2D gels of whole cell extracts were used. Preliminary proteomic data resulting from whole cell extracts showed different effects for TiO2-NPs and Cu-NPs. Modifications of the expression of several proteins involved in different pathways such as, for example, signal transduction, endosome-lysosome pathway, Krebs cycle, oxidative stress response have been underscored. These first results validate our proteomics approach and open a new wide field of investigation for NPs impact on macrophagesComment: Nanosafe2010: International Conference on Safe Production and Use of Nanomaterials 16-18 November 2010, Grenoble, France, Grenoble : France (2010

    Viability-based computation of spatially constrained minimum time trajectories for an autonomous underwater vehicle: implementation and experiments.

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    A viability algorithm is developed to compute the constrained minimum time function for general dynamical systems. The algorithm is instantiated for a speciïŹc dynamics(Dubin’s vehicle forced by a ïŹ‚ow ïŹeld) in order to numerically solve the minimum time problem. With the speciïŹc dynamics considered, the framework of hybrid systems enables us to solve the problem efïŹciently. The algorithm is implemented in C using epigraphical techniques to reduce the dimension of the problem. The feasibility of this optimal trajectory algorithm is tested in an experiment with a Light Autonomous Underwater Vehicle (LAUV) system. The hydrodynamics of the LAUV are analyzed in order to develop a low-dimension vehicle model. Deployment results from experiments performed in the Sacramento River in California are presented, which show good performance of the algorithm.trajectories; underwater vehicle; viability algorithm; hybrid systems; implementation;

    Investigating Gender Disparities in Internal Medicine Residency Awards

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    Background: Significant gender disparities persist in career advancement for physicians. Studies have highlighted the lack of female representation in awards from both academic institutions and professional societies; these awards play a role in promotions, making them a fundamental building block of success. Objectives: We aim to explore the gender breakdown among resident awards presented by several Internal Medicine residency programs across the United States in this pilot study. Our ultimate goals are to define disparities in award selection, determine what variables contribute to these disparities, and work to mitigate these variables. Methods/Research: We generated a survey in REDCap to collect retrospective data about resident award selection from academic Internal Medicine residency programs across the country. This survey gathered awards data from 2009-2019 and included variables such as gender breakdown of the program, gender of resident award recipients, and details about how awards are selected. Eight programs completed the survey; these programs were from six different states in various geographic regions. Overall 43.1 percent of residents were female. Across all residency programs and years, there were 51 distinct resident awards with 290 (39.7%) female winners. Of the 51 distinct awards, there were 10 which were awarded to female residents with the same or higher frequency as males; 6 of these mentioned words that have been differentially associated with women in medicine such as “ambulatory,” “community,” “compassion,” and “humanism.” In the 41 awards favoring males, there was only a single mention of the word “compassion,” and no mention of the others. Conclusions/Impact: This data shows a concerning disparity in gender of award winners. In the future we will collect data from more residency programs and perform a thorough investigation of selection mechanisms that may help mitigate bias in order to ultimately propose strategies to reduce these gender disparities.https://jdc.jefferson.edu/sexandgenderhealth/1007/thumbnail.jp

    The Role of International Administration [IA] in the Globally Engaged University

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    This paper describes best practice and effective techniques in international administration (IA) within the Globally Engaged University. The Globally Engaged University is one that continually promotes, communicates, initiates, controls, monitors, and evaluates international activity in at least one of its major academic units [5]. Emphasis is IA within engineering and technology higher education. Nonetheless, the description of best practice in IA is also applicable to various other academic disciplines at the Globally Engaged University. In describing best practice in IA, the paper adds the perspective of the authors' applied experience. The combined IA experience among the coauthors includes successful international programs in South and Southeast Asia, the European Union, and the USA. Three of the co-authors are senior administrators within one and the same university in the USA. Another co-author is a senior administrator at a university in Malaysia. Broadening the perspective yet further, another team member is an IA specialist at a Globally Engaged University in Poland. The authors compare and contrast techniques and organizational structure common to IA at three differing locations: USA, Malaysia, and Poland as a central member state of the European Union

    Evidence for Marine Influence on a Low-Gradient Coastal Plain: Ichnology and Invertebrate Paleontology of the Lower Tongue River Member (Fort Union Formation, Middle Paleocene), Western Williston Basin, U.S.A.

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    The Paleocene Tongue River Member of the Fort Union Formation contains trace-fossil associations indicative of marine influence in otherwise freshwater facies. The identified ichnogenera include: Arenicolites, Diplocraterion, Monocraterion, Ophiomorpha, Rhizocorallium, Skolithos linearis, Teichichnus, Thalassinoides, and one form of uncertain affinity. Two species of the marine diatom Coscinodiscus occur a few meters above the base of the member. The burrows occur in at least five discrete, thin, rippled, fine-grained sandstone beds within the lower 85 m of the member west of the Cedar Creek anticline (CCA) in the Signal Butte, Terry Badlands, and Pine Hills areas. Two discrete burrowed beds are found in the lower 10 m of the member east of the CCA in the little Missouri River area. Abundant freshwater ostracodes include Bisulcocypridea arvadensis, Candona, and Cypridopsis. Freshwater bivalves include Plesielliptio and Pachydon mactriformis. We recognize four fossil assemblages that represent fluvio-lacustrine, proximal estuarine, central estuarine, and distal estuarine environments. Biostratal alternations between fresh- and brackish-water assemblages indicate that the Tongue River Member was deposited along a low-gradient coastal plain that was repeatedly inundated from the east by the Cannonball Sea. The existence of marine-influenced beds in the Tongue River Member invalidates the basis for the Slope Formation

    Charges and fluxes in Maxwell theory on compact manifolds with boundary

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    We investigate the charges and fluxes that can occur in higher-order Abelian gauge theories defined on compact space-time manifolds with boundary. The boundary is necessary to supply a destination to the electric lines of force emanating from brane sources, thus allowing non-zero net electric charges, but it also introduces new types of electric and magnetic flux. The resulting structure of currents, charges, and fluxes is studied and expressed in the language of relative homology and de Rham cohomology and the corresponding abelian groups. These can be organised in terms of a pair of exact sequences related by the Poincar\'e-Lefschetz isomorphism and by a weaker flip symmetry exchanging the ends of the sequences. It is shown how all this structure is brought into play by the imposition of the appropriately generalised Maxwell's equations. The requirement that these equations be integrable restricts the world-volume of a permitted brane (assumed closed) to be homologous to a cycle on the boundary of space-time. All electric charges and magnetic fluxes are quantised and satisfy the Dirac quantisation condition. But through some boundary cycles there may be unquantised electric fluxes associated with quantised magnetic fluxes and so dyonic in nature.Comment: 28 pages, plain Te

    The Vice Chair of Education in Emergency Medicine: A Workforce Study to Establish the Role, Clarify Responsibilities, and Plan for Success

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    ObjectivesDespite increasing prevalence in emergency medicine (EM), the vice chair of education (VCE) role remains ambiguous with regard to associated responsibilities and expectations. This study aimed to identify training experiences of current VCEs, clarify responsibilities, review career paths, and gather data to inform a unified job description.MethodsA 40‐item, anonymous survey was electronically sent to EM VCEs. VCEs were identified through EM chairs, residency program directors, and residency coordinators through solicitation e‐mails distributed through respective listservs. Quantitative data are reported as percentages with 95% confidence intervals and continuous variables as medians with interquartiles (IQRs). Open‐ and axial‐coding methods were used to organize qualitative data into thematic categories.ResultsForty‐seven of 59 VCEs completed the survey (79.6% response rate); 74.4% were male and 89.3% were white. Average time in the role was 3.56 years (median = 3.0 years, IQR = 4.0 years), with 74.5% serving as inaugural VCE. Many respondents held at least one additional administrative title. Most had no defined job description (68.9%) and reported no defined metrics of success (88.6%). Almost 78% received a reduction in clinical duties, with an average reduction of 27.7% protected time effort (median = 27.2%, IQR = 22.5%). Responsibilities thematically link to faculty affairs and promotion of the departmental educational mission and scholarship.ConclusionGiven the variability in expectations observed, the authors suggest the adoption of a unified VCE job description with detailed responsibilities and performance metrics to ensure success in the role. Efforts to improve the diversity of VCEs are encouraged to better match the diversity of learners.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154254/1/aet210407_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154254/2/aet210407.pd
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