49,851 research outputs found

    An Analytic Method of Interpretation of Electron Diffraction Photographs of Gases

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    An analytic procedure to be used in the interpretation of electron diffraction photographs for gases is developed. The experimentally determined positions of the maxima and minima are employed to solve directly for the interatomic distances through successive approximations. The method is then generalized so as to be applicable to molecules in which rotations or large oscillations about a bond are permitted. As a test, three sets of data which have already been published are recalculated yielding somewhat altered values for the molecular parameters. New diffraction photographs of propane are analyzed. It is pointed out that the number of theoretical intensity curves which must be computed to obtain the correct structure is thereby greatly reduced

    Air conditioning system and component therefore distributing air flow from opposite directions

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    The air conditioning system comprises a plurality of separate air conditioning units coupled to a common supply duct such that air may be introduced into the supply duct in two opposite flow directions. A plurality of outlets such as registers or auxiliary or branch ducts communicate with the supply duct and valve means are disposed in the supply duct at at least some of the outlets for automatically channelling a controllable amount of air from the supply duct to the associated outlet regardless of the direction of air flow within the supply duct. The valve means comprises an automatic air volume control apparatus for distribution within the air supply duct into which air may be introduced from two opposite directions. The apparatus incorporates a freely swinging movable vane in the supply duct to automatically channel into the associated outlet only the deflected air flow which has the higher relative pressure

    The cell cycle–apoptosis connection revisited in the adult brain

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    Adult neurogenesis is studied in vivo using thymidine analogues such as bromodeoxyuridine (BrdU) to label DNA synthesis during the S phase of the cell cycle. However, BrdU may also label DNA synthesis events not directly related to cell proliferation, such as DNA repair and/or abortive reentry into the cell cycle, which can occur as part of an apoptotic process in postmitotic neurons. In this study, we used three well-characterized models of injury-induced neuronal apoptosis and the combined visualization of cell birth (BrdU labeling) and death (Tdt-mediated dUTP-biotin nick end labeling) to investigate the specificity of BrdU incorporation in the adult mouse brain in vivo. We present evidence that BrdU is not significantly incorporated during DNA repair and that labeling is not detected in vulnerable or dying postmitotic neurons, even when a high dose of BrdU is directly infused into the brain. These findings have important implications for a controversy surrounding adult neurogenesis: the connection between cell cycle reactivation and apoptosis of terminally differentiated neurons

    The Orientation of Unsymmetrical Molecules at Interfaces

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    A function giving the distribution of the angles of orientation of the molecular axes from the normal to the interface can be obtained if one makes use of a number of special assumptions regarding the forces of orientation. This is compared with the distribution calculated on assuming an extreme form of Langmuir's principle of independent surface action. The importance of having such a function is pointed out

    Value Based Benchmarking and Market Partitioning

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    The paper offers an analytical approach for an integrated treatment of market partitioning and benchmarking within a Data Envelopment Analysis (DEA) framework. Based on an empirical example from the automotive industry we measure product effciency from the customer’s perspective. This is interpreted as customer value, i. e., as a ratio of outputs that customers obtain from a product (e. g., resale value, reliability) and inputs that customers have to invest (e. g., price, running costs). Products offering a maximum customer value relative to all other alternatives represent effcient peers, which constitute benchmarks for different sub-markets. All products benchmarked via the same effcient peer(s) constitute a sub-market including the benchmarks.Data Envelopment Analysis (DEA), Market Partitioning, Benchmarking, Product-Market Structuring, Customer Value

    Studies of specific nuclear light bulb and open-cycle vortex stabilized gaseous nuclear rocket engines

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    Specific nuclear light bulb and open-cycle vortex stabilized gaseous nuclear rocket engine design
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