31 research outputs found

    Users' guides to the medical literature: how to use an article about mortality in a humanitarian emergency

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    The accurate interpretation of mortality surveys in humanitarian crises is useful for both public health responses and security responses. Recent examples suggest that few medical personnel and researchers can accurately interpret the validity of a mortality survey in these settings. Using an example of a mortality survey from the Democratic Republic of Congo (DRC), we demonstrate important methodological considerations that readers should keep in mind when reading a mortality survey to determine the validity of the study and the applicability of the findings to their settings

    Can environmental or occupational hazards alter the sex ratio at birth? A systematic review

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    More than 100 studies have examined whether environmental or occupational exposures of parents affect the sex ratio of their offspring at birth. For this review, we searched Medline and Web of Science using the terms ‘sex ratio at birth’ and ‘sex ratio and exposure’ for all dates, and reviewed bibliographies of relevant studies to find additional articles. This review focuses on exposures that have been the subject of at least four studies including polychlorinated biphenyls (PCBs), dioxins, pesticides, lead and other metals, radiation, boron, and g-forces. For paternal exposures, only dioxins and PCBs were consistently associated with sex ratios higher or lower than the expected 1.06. Dioxins were associated with a decreased proportion of male births, whereas PCBs were associated with an increased proportion of male births. There was limited evidence for a decrease in the proportion of male births after paternal exposure to DBCP, lead, methylmercury, non-ionizing radiation, ionizing radiation treatment for childhood cancer, boron, or g-forces. Few studies have found higher or lower sex ratios associated with maternal exposures. Studies in humans and animals have found a reduction in the number of male births associated with lower male fertility, but the mechanism by which environmental hazards might change the sex ratio has not yet been established

    Evidence of Inbreeding Depression on Human Height

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    WOS:000306840400001Peer reviewe

    Champagne: Automated Whole-Genome Phylogenomic Character Matrix Method Using Large Genomic Indels for Homoplasy-Free Inference.

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    We present Champagne, a whole-genome method for generating character matrices for phylogenomic analysis using large genomic indel events. By rigorously picking orthologous genes and locating large insertion and deletion events, Champagne delivers a character matrix that considerably reduces homoplasy compared with morphological and nucleotide-based matrices, on both established phylogenies and difficult-to-resolve nodes in the mammalian tree. Champagne provides ample evidence in the form of genomic structural variation to support incomplete lineage sorting and possible introgression in Paenungulata and human-chimp-gorilla which were previously inferred primarily through matrices composed of aligned single-nucleotide characters. Champagne also offers further evidence for Myomorpha as sister to Sciuridae and Hystricomorpha in the rodent tree. Champagne harbors distinct theoretical advantages as an automated method that produces nearly homoplasy-free character matrices on the whole-genome scale

    Tuning current rectification across molecular junctions

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    We demonstrate the ability to tune the current rectification in metal-molecule-metal junctions through control of the interaction strength of one of the two metal-molecule contacts. Current-voltage characteristics of thiolate bound molecular wires with a nitro or pyridine termination show that the extent of current rectification in a molecular junction correlates well with the extent of coupling between the chemical linker and metal electrode

    Ligand effects on charge transport in platinum(II) acetylides

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    To investigate the electrical characteristics of organometallic complexes as molecular conductors, organometallic π-conjugated molecules of the type trans-[PtL2(C≡CC6H4SAc-4)2], where L=PCy3, PBu3, PPh3, P(OEt)3, P(OPh)3, were synthesized and characterized by NMR, IR, UV, and X-ray spectroscopies. For the three complexes (L=PCy3, PPh3, and P(OEt)3) that could be measured using a cross-wire junction technique, the current-voltage (I-V) characteristics of a molecular monolayer of these complexes showed no ligand effect, despite spectroscopic evidence that electronic interaction between the phosphine ligands and the π-system does occur. It was concluded that the tunneling efficiency across the molecule is the determining factor for conduction in this metal-molecule-metal system. It was also shown that the incorporation of a transition metal in π -conjugated molecular wires does not adversely affect charge transport compared to all-carbon π -conjugated molecular wires
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