95 research outputs found

    The DMSP/MFR total ozone and radiance data base

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    This report describes the entries in sufficient detail so that the data base might be useful to others. The characteristics of the MFR sensor are briefly discussed and a complete index to the data base tapes is given

    Light amplification without stimulated emission: Beyond the standard quantum limit to the laser linewidth

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    The standard quantum limit to the linewidth of a laser for which the gain medium can be adiabatically eliminated is l(0) = K/2 (n) over bar Here K is the intensity damping rate and (n) over bar the mean photon number. This contains equal contributions from the loss and gain processes, so that simple arguments which attribute the linewidth wholly to phase noise from spontaneous gain are wrong. I show that an unstimulated gain process actually introduces no phase noise, so that the ultimate quantum limit to the linewidth comes from the loss alone and is equal to l(ult) = K/4 (n) over bar. I investigate a number of physical gain mechanisms which attempt to achieve gain without phase noise: a linear atom-field coupling with a finite interaction time, a nonlinear atom-field coupling, and adiabatic photon transfer using a counterintuitive pulse sequence. The first at best reaches the standard limit l(0), the second reaches 3/4l(0), and the third reaches the ultimate limit of l(ult)= 1/2l(0). [S1050-2947(99)03711-7]

    Chronic NMDA administration to rats increases brain pro-apoptotic factors while decreasing anti-Apoptotic factors and causes cell death

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    <p>Abstract</p> <p>Background</p> <p>Chronic <it>N</it>-Methyl-d-aspartate (NMDA) administration to rats is reported to increase arachidonic acid signaling and upregulate neuroinflammatory markers in rat brain. These changes may damage brain cells. In this study, we determined if chronic NMDA administration (25 mg/kg i.p., 21 days) to rats would alter expression of pro- and anti-apoptotic factors in frontal cortex, compared with vehicle control.</p> <p>Results</p> <p>Using real time RT-PCR and Western blotting, chronic NMDA administration was shown to decrease mRNA and protein levels of anti-apoptotic markers Bcl-2 and BDNF, and of their transcription factor phospho-CREB in the cortex. Expression of pro-apoptotic Bax, Bad, and 14-3-3ζ was increased, as well as Fluoro-Jade B (FJB) staining, a marker of neuronal loss.</p> <p>Conclusion</p> <p>This alteration in the balance between pro- and anti-apoptotic factors by chronic NMDA receptor activation in this animal model may contribute to neuronal loss, and further suggests that the model can be used to examine multiple processes involved in excitotoxicity.</p

    Brachypodium distachyon as a model for defining the allergen potential of non-prolamin proteins

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    Epitope databases and the protein sequences of published plant genomes are suitable to identify some of the proteins causing food allergies and sensitivities. Brachypodium distachyon, a diploid wild grass with a sequenced genome and low prolamin content, is the closest relative of the allergen cereals, such as wheat or barley. Using the Brachypodium genome sequence, a workflow has been developed to identify potentially harmful proteins which may cause either celiac disease or wheat allergy-related symptoms. Seed tissue-specific expression of the potential allergens has been determined, and intact epitopes following an in silico digestion with several endopeptidases have been identified. Molecular function of allergen proteins has been evaluated using Gene Ontology terms. Biologically overrepresented proteins and potentially allergen protein families have been identified. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10142-012-0294-z) contains supplementary material, which is available to authorized users

    Trinta anos de sintaxe gerativa no Brasil

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