9,780 research outputs found

    The Aaron Diamond Foundation AIDS Research in New York City

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    Case study examines a foundation that spent down its $200 million endowment over 10 years on programs in medical research, minority education, and culture in New York City

    Tribo-Corrosion behaviour of TiCxOy thin films in bio fluids

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    In recent years, the development of thin film systems for decorative applications has attracted significant attention in scientific research. These decorative coatings require, not only an attractive appearance for market applications, but also an ability to protect the surface underneath. Because of this, corrosion, wear and their combined effects (termed tribo-corrosion) are particularly important for lifetime prediction. The tribo-corrosion behaviour of a range of single layered titanium oxycarbide, TiCxOy,coatings, produced by DC reactive magnetron sputtering, has been studied and reported as a function of electrode potential (-0.9 V, -0.5 V, 0.0 V and +0.5 V) and applied load (3, 6 and 9 N). The study was conducted in a reciprocating sliding tribosystem (Plint TE 67/E) in a bio fluid (an artificial perspiration solution) at room temperature. During the wear tests, both the open-circuit potential and the corrosion current were monitored. The results showed that electrode potential and load have a significant influence on the total material loss. The variations in Rp (polarization resistance) and Cf(capacitance) before and after sliding, obtained by Electrochemical Impedance Spectroscopy (EIS) were evaluated in order to provide an understanding of the resistance of the film in such conditions. Tribo-corrosion maps were generated, based on the results, indicating the change in mechanisms of the tribological and corrosion parameters for such coatings

    Micro-abrasion-corrosion interactions of Ni-Cr/WC based coatings : approaches to construction of tribo-corrosion maps for the abrasion-corrosion synergism

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    The process of micro-abrasion-corrosion has been the subject of much research in recent years due to the fact that the action of micron sized particles, typically less than 10 um in diameter, can cause significant degradation of materials in many diverse environments involving aqueous corrosion. Cermet based coatings are often used to combat micro-abrasion-corrosion, but has been little work carried out to characterize the performance of such coatings exposed to micro-abrasion-corrosion or to provide a basis for coating optimisation. In addition, a basis for defining the various micro-abrasion-corrosion interactions has not been suggested to date. In this study the micro-abrasion-corrosion performance of a Ni-Cr/WC coating was assessed and compared to the performance of the steel substrate. The results were used to identify regimes of micro-abrasion as a function of applied load and pH of the solution. In addition, micro-abrasion-corrosion maps were constructed based on the results, showing the variation between micro-abrasion-corrosion regimes, as a function of applied load and pH of the solution

    An overview of the marine fish landings in Andhra Pradesh during 2014

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    The estimated marine fish landings in Andhra Pradesh during the year 2014 was 3.41 lakh tonnes (t) as compared to 2.66 lakh t in 2013 showing an increase of 28%. The state’s contribution to the all India landings during 2014 was 9.5 %. Resources such as Indian mackerel and lesser sardines constituted the maximum, being 16.3% and 12.2% of the landings respectively. Tunnies and penaeid prawns landings contributed 8% each while the other important species/ groups were ribbon fishes 5.9%, carangids 5.5%, perches 4.2%, croakers 3.8%, oil sardine 3.5%, goatfishes 2.3%, seer fishes 2.3%, Stolephorus spp. 2%, crabs 2%, Silverbellies 1.9% and elasmobranchs 1.6%. Landings of crabs, Indian mackerel, oil sardine, lesser sardines, seer fishes and tunnies had increased by 0.4, 0.65, 1.04, 2.32, 0.56, 1.07 times respectively when compared to 2013 landing trends. Other clupeids and silverbellies had decreased when compared to the previous year landings

    Scanning electron microscopic observations on the third ventricular floor of the rat following cervical sympathectomy

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    Various investigators have shown that unilateral ganglionectomy or transection of the internal and external carotid nerves leads to a regenerative response in the ipsilateral superior cervical ganglion and to uninjured mature sympathetic neurons sprouting into bilaterally innervated shared target organs. In this study changes in the supraependymal neuronal network following unilateral and bilateral cervical sympathectomy on the infundibular floor of the third ventricle were studied by scanning electron microscopy in comparison with normal and sham-operated control animals. After unilateral cervical sympathectomy there was a great increase in the number of varicose nerve fibres on the infundibular floor as compared to the normal and sham-operated control animals. Not only was there an increase in the number of nerve fibres, but also their varicosities were substantially larger than those normally present on the ependymal surface. This study indicates the possible sympathetic projections from the superior cervical ganglia to the ependymal surface of the third cerebral ventricle

    Nest Site Characteristics and Breeding Biology of Flammmulated Owls in Missoula Valley

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    Seidensticker, Mathew, M.S., Spring 2011 Environmental Studies Nest Sites and Breeding Biology of Flammulated Owls in Missoula Valley Chairperson: Len Broberg The Flammulated Owl is listed as a sensitive or species of concern with United States Forest Service, Bureau of Land Management, and Montana Fish, Wildlife and Parks. Despite these listings the Flammulated Owl is little studied in Montana. Although region-wide surveys have greatly increased our understanding of distribution and landscape level habitat associations of Flammulated Owls, information about breeding is lacking. In order to address this need for breeding information I searched for and quantified nest site characteristics and breeding biology of Flammulated Owls in Missoula Valley from 2008-2010. I located 17 Flammulated Owl territories, four nests, and banded 12 individuals. I also utilized radio telemetry to help gather information about roosting and foraging habitat. Although our sample size is limited, nest site characteristics and breeding parameters in my study were within the range of information published by other authors for Flammulated Owl nests. Much more information about Flammulated Owl breeding biology is needed to comprehensively assess the status of this owl species and build scientifically responsible models for managing habitat in Montana

    Properties and occurrence rates of KeplerKepler exoplanet candidates as a function of host star metallicity from the DR25 catalog

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    Correlations between the occurrence rate of exoplanets and their host star properties provide important clues about the planet formation processes. We studied the dependence of the observed properties of exoplanets (radius, mass, and orbital period) as a function of their host star metallicity. We analyzed the planetary radii and orbital periods of over 2800 KeplerKepler candidates from the latest KeplerKepler data release DR25 (Q1-Q17) with revised planetary radii based on GaiaGaia~DR2 as a function of host star metallicity (from the Q1-Q17 (DR25) stellar and planet catalog). With a much larger sample and improved radius measurements, we are able to reconfirm previous results in the literature. We show that the average metallicity of the host star increases as the radius of the planet increases. We demonstrate this by first calculating the average host star metallicity for different radius bins and then supplementing these results by calculating the occurrence rate as a function of planetary radius and host star metallicity. We find a similar trend between host star metallicity and planet mass: the average host star metallicity increases with increasing planet mass. This trend, however, reverses for masses >4.0MJ> 4.0\, M_\mathrm{J}: host star metallicity drops with increasing planetary mass. We further examined the correlation between the host star metallicity and the orbital period of the planet. We find that for planets with orbital periods less than 10 days, the average metallicity of the host star is higher than that for planets with periods greater than 10 days.Comment: 14 pages, 13 Figures, Accepted for publication in The Astronomical Journa
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