12 research outputs found

    Supernova siblings and their parent galaxies in the Zwicky Transient Facility Bright Transient Survey

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    International audienceSupernova (SN) siblings – two or more SNe in the same parent galaxy – are useful tools for exploring progenitor stellar populations as well as properties of the host galaxies such as distance, star-formation rate, dust extinction, and metallicity. Since the average SN rate for a Milky Way-type galaxy is just one per century, a large imaging survey is required to discover an appreciable sample of SN siblings. From the wide-field Zwicky Transient Facility (ZTF) Bright Transient Survey (which aims for spectroscopic completeness for all transients which peak brighter than r < 18.5 mag) we present 10 SN siblings in five parent galaxies. For each of these families, we analyse the SN’s location within the host and its underlying stellar population, finding agreement with expectations that SNe from more massive progenitors are found nearer to their host core and in regions of more active star formation. We also present an analysis of the relative rates of core collapse and thermonuclear SN siblings, finding a significantly lower ratio than past SN sibling samples due to the unbiased nature of the ZTF

    Review: A critical evaluation of arguments opposing male circumcision for HIV prevention in developed countries

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    A potential impediment to evidence-based policy development on medical male circumcision (MC) for HIV prevention in all countries worldwide is the uncritical acceptance by some of arguments used by opponents of this procedure. Here we evaluate recent opinion-pieces of 13 individuals opposed to MC. We find that these statements misrepresent good studies, selectively cite references, some containing fallacious information, and draw erroneous conclusions. In marked contrast, the scientific evidence shows MC to be a simple, low-risk procedure with very little or no adverse long-term effect on sexual function, sensitivity, sensation during arousal or overall satisfaction. Unscientific arguments have been recently used to drive ballot measures aimed at banning MC of minors in the USA, eliminate insurance coverage for medical MC for low-income families, and threaten large fines and incarceration for health care providers. Medical MC is a preventative health measure akin to immunisation, given its protective effect against HIV infection, genital cancers and various other conditions. Protection afforded by neonatal MC against a diversity of common medical conditions starts in infancy with urinary tract infections and extends throughout life. Besides protection in adulthood against acquiring HIV, MC also reduces morbidity and mortality from multiple other sexually transmitted infections (STIs) and genital cancers in men and their female sexual partners. It is estimated that over their lifetime one-third of uncircumcised males will suffer at least one foreskin-related medical condition. The scientific evidence indicates that medical MC is safe and effective. Its favourable risk/benefit ratio and cost/benefit support the advantages of medical MC

    Substitution therapy for heroin addiction

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    Substitution treatment for heroin addiction, defined here as maintenance prescribing of opioid agonist drugs to opioid dependent subjects, has increased in the last decade. The recent history of substitution treatment in five countries--Canada, the U.K., Australia, Israel, and France--is reviewed. In all five countries, the critical issues around substitution treatment are similar. The first key issue concerns the balance between making treatment accessible and attractive, and minimizing diversion to the black market. The second issue concerns the role of primary health care in delivering MMT. In general, there has been increasing involvement of primary health care, with training and support for practitioners. However, there remains uncertainty and official ambivalence over whether treatment should be restricted to specialist clinics and practitioners, or available through primary care. Most importantly, underlying these issues is the problem of stigma being associated with both addiction, and with substitution treatment. The underlying problem that treatment is often at odds with community values places enormous strains on substitution treatment, and makes the treatment system vulnerable to shifting community support and abrupt, politically-driven changes in policy

    Nanotribology and Materials Characterization of MEMS/NEMS and BioMEMS/BioNEMS Materials and Devices

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    Major Kinds of Drug Targets in Chagas Disease or American Trypanosomiasis

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