43 research outputs found

    Faculty Newsletter

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    Volume 5, Number 1 August/September 2000Newsletter sent to faculty in August of 2000 with information regarding library services and resource

    Faculty Newsletter

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    Volume 6, Number 1 August/September 2001Newsletter sent to faculty in August of 2001 with information regarding library services and resource

    The auditory cortex of the bat Phyllostomus discolor: Localization and organization of basic response properties

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    <p>Abstract</p> <p>Background</p> <p>The mammalian auditory cortex can be subdivided into various fields characterized by neurophysiological and neuroarchitectural properties and by connections with different nuclei of the thalamus. Besides the primary auditory cortex, echolocating bats have cortical fields for the processing of temporal and spectral features of the echolocation pulses. This paper reports on location, neuroarchitecture and basic functional organization of the auditory cortex of the microchiropteran bat <it>Phyllostomus discolor </it>(family: Phyllostomidae).</p> <p>Results</p> <p>The auditory cortical area of <it>P. discolor </it>is located at parieto-temporal portions of the neocortex. It covers a rostro-caudal range of about 4800 μm and a medio-lateral distance of about 7000 μm on the flattened cortical surface.</p> <p>The auditory cortices of ten adult <it>P. discolor </it>were electrophysiologically mapped in detail. Responses of 849 units (single neurons and neuronal clusters up to three neurons) to pure tone stimulation were recorded extracellularly. Cortical units were characterized and classified depending on their response properties such as best frequency, auditory threshold, first spike latency, response duration, width and shape of the frequency response area and binaural interactions.</p> <p>Based on neurophysiological and neuroanatomical criteria, the auditory cortex of <it>P. discolor </it>could be subdivided into anterior and posterior ventral fields and anterior and posterior dorsal fields. The representation of response properties within the different auditory cortical fields was analyzed in detail. The two ventral fields were distinguished by their tonotopic organization with opposing frequency gradients. The dorsal cortical fields were not tonotopically organized but contained neurons that were responsive to high frequencies only.</p> <p>Conclusion</p> <p>The auditory cortex of <it>P. discolor </it>resembles the auditory cortex of other phyllostomid bats in size and basic functional organization. The tonotopically organized posterior ventral field might represent the primary auditory cortex and the tonotopically organized anterior ventral field seems to be similar to the anterior auditory field of other mammals. As most energy of the echolocation pulse of <it>P. discolor </it>is contained in the high-frequency range, the non-tonotopically organized high-frequency dorsal region seems to be particularly important for echolocation.</p

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Settlement of Alabama before 1819

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    Physiological quality in seeds obtained by topcrosses between vegetable soybean and grain type

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    Attempts were made to study the gene introgression for high physiological quality from adapted cultivars in the vegetable soybean (exotic). Promising results were obtained for all topocrosses, with increased in germination percentage in majority. General mean of the germination percentage in topcrosses with large seeds exotic parental showed an increase from 28 to 46%, and topcrosses with small seeds exotic parental, from 54 up to 60%, both cases compared to self pollinated exotic parental. Related to variance, the topcrosses showed higher values than the self pollinated exotic parental, showing to be possible the selecion of promising materials.<br>Esforços foram feitos para estudar o efeito da introgressão de genes para alta qualidade fisiológica de sementes de cultivares adaptados na soja alimento (considerados exóticos). Resultados promissores foram obtidos para todos os topocruzamentos, com aumento na porcentagem de germinação na maioria dos materiais avaliados. A média geral da porcentagem de germinação nos topocruzamentos com parentais exóticos de sementes grandes mostraram aumentos de 28 a 46%, e topocruzamentos com parentais exóticos de sementes pequenas de 54 a mais de 60%, ambos os casos comparados com os parentais exóticos auto fecundados. Em relação a variância, os topocruzamentos apresentaram valores maiores do que os parentais exóticos auto fecundados, mostrando a possibilidade de seleção de soja alimento com sementes com maiores porcentagens de emergência
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