9,874 research outputs found

    Apparatus and process for microbial detection and enumeration

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    An apparatus and process for detecting and enumerating specific microorganisms from large volume samples containing small numbers of the microorganisms is presented. The large volume samples are filtered through a membrane filter to concentrate the microorganisms. The filter is positioned between two absorbent pads and previously moistened with a growth medium for the microorganisms. A pair of electrodes are disposed against the filter and the pad electrode filter assembly is retained within a petri dish by retainer ring. The cover is positioned on base of petri dish and sealed at the edges by a parafilm seal prior to being electrically connected via connectors to a strip chart recorder for detecting and enumerating the microorganisms collected on filter

    Driving extreme variability: The evolving corona and evidence for jet launching in Markarian 335

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    Variations in the X-ray emission from the narrow line Seyfert 1 galaxy, Markarian 335 (Mrk 335), are studied on both long and short timescales through observations made between 2006 and 2013 with XMM-Newton, Suzaku and NuSTAR. Changes in the geometry and energetics of the corona that give rise to this variability are inferred through measurements of the relativistically blurred reflection seen from the accretion disc. On long timescales, we find that during the high flux epochs the corona has expanded, covering the inner regions of the accretion disc out to a radius of 26(-7,+10)rg. The corona contracts to within 12rg and 5rg in the intermediate and low flux epochs, respectively. While the earlier high flux observation made in 2006 is consistent with a corona extending over the inner part of the accretion disc, a later high flux observation that year revealed that the X-ray source had become collimated into a vertically-extended jet-like corona and suggested relativistic motion of material upward. On short timescales, we find that an X-ray flare during a low flux epoch in 2013 corresponded to a reconfiguration from a slightly extended corona to one much more compact, within just 2~3rg of the black hole. There is evidence that during the flare itself, the spectrum softened and the corona became collimated and slightly extended vertically as if a jet-launching event was aborted. Understanding the evolution of the X-ray emitting corona may reveal the underlying mechanism by which the luminous X-ray sources in AGN are powered.Comment: 21 pages, 9 figures. Accepted for publication in MNRA

    Description and field test of an in situ coliform monitoring system

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    A prototype in situ system for monitoring the levels of fecal coliforms in shallow water bodies was developed and evaluated. This system was based on the known relationship between the concentration of the coliform bacteria and the amount of hydrogen they produce during growth in a complex organic media. The prototype system consists of a sampler platform, which sits on the bottom; a surface buoy, which transmits sampler-generated data; and a shore station, which receives, displays the data, and controls the sampler. The concept of remote monitoring of fecal coliform concentrations by utilizing a system based on the electrochemical method was verified during the evaluation of the prototype

    Giotto Extended Mission (GEM)

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    The primary objectives of the Giotto Extended Mission (GEM), are to determine the composition and physical state of the Grigg Skjellerup Comet's nucleus; to determine the processes that govern the composition and distribution of neutral and ionized species in the cometary atmosphere. Giotto consists of a single European Space Agency (ESA) spacecraft that was launched in 1985 from Center Spatial Guyanis in French Guiana on an Ariane launch vehicle. After a successful launch into geostationary orbit and a heliocentric transfer trajectory, the spacecraft successfully encountered Halley's Comet in 1986. One month after encountering Halley's Comet, Mar. 1986, the spacecraft was placed in hibernation in a heliocentric orbit slightly less than 1 AU. Between Feb. and Jul. 1990 the spacecraft was successfully reactivated, checked out, and placed on a trajectory course to intercept comet Grigg Skjellerup. The spacecraft has been in hibernation since Jul. 1990. Information is presented in tabular form in the following areas: coverage goals, Deep Space Network Support, frequency assignments, telemetry, command, and tracking support responsibility

    The gender and access to health services study: final report

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    Men and women frequently think and behave differently. To observe this is not to suggest anything so absurdly simple as that there are only male and female ways of being; behaviours and thought processes vary according to numerous other factors besides gender. That this is very generally the case however, does mean that there are broad - and often broadly predictable - differences in the way men and women engage with the world. Most commercial organisations understand this very well and plan accordingly. Many public authorities recognise it too and take these differences into account when developing and providing services. For historical reasons however the NHS has rarely done so. It is widely known that there are differences between men and women in the incidence and prevalence of most health conditions. Sometimes there are clear biological reasons for these differences but often there are not. Where biology offers little or no enlightenment, other questions need to be asked: · Do men and women behave in ways that predispose them to particular health conditions to different degrees? · Do men and women use health services with different degrees of effectiveness? · Do men and women receive differerent kinds of service from the NHS? The answer is – yes, these things happen frequently. This is sometimes to the disadvantage of one sex and sometimes to the disadvantage of the other. Sometimes it is to the disadvantage of both. And when these things happen, health outcomes are often affected. This report looks at the reasons why gender is such an important and fundamental determinant of health status and considers the ways in which gender inequalities can be tackled within the present legislative and policy framework. It also brings together the knowledge and evidence in relation to six specific areas of health concerns

    Multimegawatt thermionic reactor systems for space applications

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    Design features and performance characteristics of thermionic reactor systems for space application
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