1,213 research outputs found

    estMOI: estimating multiplicity of infection using parasite deep sequencing data.

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    Individuals living in endemic areas generally harbour multiple parasite strains. Multiplicity of infection (MOI) can be an indicator of immune status and transmission intensity. It has a potentially confounding effect on a number of population genetic analyses, which often assume isolates are clonal. Polymerase chain reaction-based approaches to estimate MOI can lack sensitivity. For example, in the human malaria parasite Plasmodium falciparum, genotyping of the merozoite surface protein (MSP1/2) genes is a standard method for assessing MOI, despite the apparent problem of underestimation. The availability of deep coverage data from massively parallizable sequencing technologies means that MOI can be detected genome wide by considering the abundance of heterozygous genotypes. Here, we present a method to estimate MOI, which considers unique combinations of polymorphisms from sequence reads. The method is implemented within the estMOI software. When applied to clinical P.falciparum isolates from three continents, we find that multiple infections are common, especially in regions with high transmission

    Biomass burning is a source of modern black carbon to equatorial Atlantic Ocean sediments

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    Black carbon is a refractory form of organic carbon formed from the incomplete combustion of fossil fuels and biomass. Riverine transport is considered the dominant pathway of black carbon to the coastal oceans. However, the provenance and pathways of black carbon to the open ocean remain unknown. Here we use both stable and radiogenic isotopes of carbon to show that sedimentary black carbon across the equatorial Atlantic Ocean is aeolian and primarily derived from biomass burning of C4-plants. Fluxes of surface sedimentary black carbon measured along an equatorial Atlantic Ocean transect using chemothermal oxidation at 375 °C were relatively consistent across the Atlantic, ranging from 0.10–0.35 mg cm−2 kyr−1. Carbon isotope values near Africa suggest the black carbon was mostly young and derived from C4 plants, whereas offshore South America, the black carbon was older and dominated by C3 plants. The black carbon radiocarbon values were similar to the reservoir corrected total organic carbon near Africa, implying little pre-aging on land and increased westwards. These findings highlight the influence of C4-biomass burning in the tropical Atlantic and the importance of aeolian deposition as a black carbon source within the global carbon cycle

    Tetra-μ-chlorido-bis­(18-crown-6)platinum(II)dipotassium(I)

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    In the title compound, [K2PtCl4(C12H24O6)2], the PtII ion is located on an inversion centre and is coordinated by four Cl atoms, forming a square-planar geometry. The KI ion is coordinated by six O atoms of the crown ether and two bridging Cl atoms. The KI ion is displaced by 0.756 (2) Å from the mean plane of the six O atoms of the crown ether. The mol­ecules are connected by weak C—H⋯O hydrogen bonds, forming an infinite two-dimensional network parallel to the (10) plane. Intra- and inter­molecular C—H⋯Cl hydrogen bonds are also observed

    PLANE LANGUAGES AND THEIR PROPERTIES

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    In this paper we study the Generalized Parikh Vector of words over three letter alphabet. For S = {a, b, c} the GPVs of words lie in the tetrahedron whose vertices are (1, 0, 0), (0, 1, 0), (0, 0, 1) and (0, 0, 0). All GPVs of words of equal length lie on the same plane. Plane languages and their language theoretical properties are studied. Further, the GPVs of words lying on surfaces are discussed. The concepts of surface language, language surface and their properties are also studied in this paper

    Statistical mechanics of columnar DNA assemblies

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    Many physical systems can be mapped onto solved or "solvable" models of magnetism. In this work, we have mapped the statistical mechanics of columnar phases of ideally helical rigid DNA -- subject to the earlier found unusual, frustrated pair potential [A. A. Kornyshev and S. Leikin, J. Chem. Phys. 107, 3656 (1997)] -- onto an exotic, unknown variant of the XY model on a fixed or restructurable lattice. Here the role of the 'spin' is played by the azimuthal orientation of the molecules. We have solved this model using a Hartree-Fock approximation, ground state calculations, and finite temperature Monte Carlo simulations. We have found peculiar spin order transitions, which may also be accompanied by positional restructuring, from hexagonal to rhombohedric lattices. Some of these have been experimentally observed in dense columnar aggregates. Note that DNA columnar phases are of great interest in biophysical research, not only because they are a useful in vitro tool for the study of DNA condensation, but also since these structures have been detected in living matter. Within the approximations made, our study provides insight into the statistical mechanics of these systems.Comment: 19 pages, 18 figure

    Motor competence and its effect on positive developmental trajectories of health

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    In 2008, Stodden and colleagues took a unique developmental approach toward addressing the potential role of motor competence in promoting positive or negative trajectories of physical activity, health-related fitness, and weight status. The conceptual model proposed synergistic relationships among physical activity, motor competence, perceived motor competence, health-related physical fit ness, and obesity with associations hypothesized to strengthen over time. At the time the model was proposed, limited evidence was available to support or refute the model hypotheses. Over the past 6 years, the number of investigations exploring these relationships has increased significantly. Thus, it is an appropriate time to examine published data that directly or indirectly relate to specific pathways noted in the conceptual model. Evidence indi cates that motor competence is positively associated with perceived competence and multiple aspects of health (i.e., physical activity, cardiorespiratory fitness, muscular strength, muscular endurance, and a healthy weight status). However, questions related to the increased strength of associations across time and antecedent/consequent mech anisms remain. An individual’s physical and psychological development is a complex and multifaceted process that synergistically evolves across time. Understanding the most salient factors that influence health and well-being and how relationships among these factors change across time is a critical need for future research in this area. This knowledge could aid in addressing the declining levels of physical activity and fitness along with the increasing rates of obesity across childhood and adolescence.4811-99FE-2ECD | Luis Paulo Rodriguesinfo:eu-repo/semantics/publishedVersio

    Rationale, design, and protocol for the prevention of low back pain in the military (POLM) trial (NCT00373009)

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    <p>Abstract</p> <p>Background</p> <p>There are few effective strategies reported for the primary prevention of low back pain (LBP). Core stabilization exercises targeting the deep abdominal and trunk musculature and psychosocial education programs addressing patient beliefs and coping styles represent the current best evidence for secondary prevention of low back pain. However, these programs have not been widely tested to determine if they are effective at preventing the primary onset and/or severity of LBP. The purpose of this cluster randomized clinical trial is to determine if a combined core stabilization exercise and education program is effective in preventing the onset and/or severity of LBP. The effect of the combined program will be compared to three other standard programs.</p> <p>Methods/Design</p> <p>Consecutive Soldiers participating in advanced individual training (AIT) will be screened for eligibility requirements and consented to study participation, as appropriate. Companies of Soldiers will be randomly assigned to receive the following standard prevention programs; a core stabilization exercise program (CSEP) alone, a CSEP with a psychosocial education (PSEP), a traditional exercise (TEP), or a TEP with a PSEP. Proximal outcome measures will be assessed at the conclusion of AIT (a 12 week training period) and include imaging of deep lumbar musculature using real-time ultrasound imaging and beliefs about LBP by self-report questionnaire. We are hypothesizing that Soldiers receiving the CSEP will have improved thickness of selected deep lumbar musculature (transversus abdominus, multifidi, and erector spinae muscles). We are also hypothesizing that Soldiers receiving the PSEP will have improved beliefs about the management of LBP. After AIT, Soldiers will be followed monthly to measure the distal outcomes of LBP occurrence and severity. This information will be collected during the subsequent 2 years following completion of AIT using a web-based data entry system. Soldiers will receive a monthly email that queries whether any LBP was experienced in the previous calendar month. Soldiers reporting LBP will enter episode-specific data related to pain intensity, pain-related disability, fear-avoidance beliefs, and pain catastrophizing. We are hypothesizing that Soldiers receiving the CSEP and PSEP will report the longest duration to first episode of LBP, the lowest frequency of LBP, and the lowest severity of LBP episodes. Statistical comparisons will be made between each of the randomly assigned prevention programs to test our hypotheses related to determining which of the 4 programs is most effective.</p> <p>Discussion</p> <p>We have presented the design and protocol for the POLM trial. Completion of this trial will provide important information on how to effectively train Soldiers for the prevention of LBP.</p> <p>Trial registration</p> <p>NCT00373009</p
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