809 research outputs found

    Unification: An international aerospace information issue

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    Science and technology projects are becoming more and more international and interdisciplinary. Other parts of the world, notably Europe, are increasingly powerful players in the aerospace business. This change has led to the development of various aerospace information initiatives in other countries. With scarce resources in all areas of government and industry, the NASA STI Program is reviewing its current acquisition and exchange practices and policies to factor in the changing requirements and new opportunities within the international community. Current NASA goals and activities are reviewed with a view toward developing a scenario for establishing an international aerospace data base, maintaining compatibility among national aerospace information systems, eliminating duplication of effort, and sharing resources through international cooperation wherever possible

    Chromogranin A in neurons of the rat cerebellum and spinal cord: quantification and sites of expression

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    Chromogranin A (CGA) is an abundant protein of dense-cored secretory vesicles in endocrine and neuronal cells. The present study, for the first time, compares CGA of neurons of the central nervous system with the CGA of adrenal origin. By S1 nucleus protection assay, we found that the 3' part of the CGA mRNA between exons 5-8 of the cerebellum and the spinal cord of the rat is homologous to that of the adrenal. In situ hybridization histochemistry revealed that CGA mRNA in the cerebellar cortex is present in cell bodies of Purkinje cells and in neurons of the deep cerebellar nuclei. The perikarya of these cells also exhibit CGA-like immunoreactivity. CGA mRNA and CGA-like immunoreactivity are also present in the motoneurons of the ventral, lateral, and dorsal horns of the rat spinal cord. The amounts of CGA, as determined by radioimmunoassay in cerebellum and spinal cord, were about one tenth of the amounts detected in the adrenal, adenohypophysis, or the olfactory bulb. The sites of CGA expression suggest that CGA may be involved in signal transduction in the motor system

    Unification: An international aerospace information opportunity

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    Science and technology projects are becoming more and more international and interdisciplinary. Other parts of the world, notably Europe, are increasingly powerful players in the aerospace industry. This change has led to the development of various aerospace information initiatives in other countries. With scarce resources in all areas of government and industry, the NASA STI Program is reviewing its current acquisition and exchange practices and policies to factor in the changing requirements and new opportunities within the international community. Current NASA goals and activities are reviewed with a new view toward developing a scenario for establishing an international aerospace database, maintaining compatibility among national aerospace information systems, eliminating duplication of effort, and sharing resources through international cooperation wherever possible

    Endocuff Vision Reduces Inspection Time Without Decreasing Lesion Detection in a Randomized Colonoscopy Trial

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    Background & Aims Mucosal exposure devices improve detection of lesions during colonoscopy and have reduced examination times in uncontrolled studies. We performed a randomized trial of Endocuff Vision vs standard colonoscopy to compare differences in withdrawal time (the primary end point). We proposed that Endocuff Vision would allow complete mucosal inspection in a shorter time without impairing lesion detection. Methods Adults older than 40 years undergoing screening or surveillance colonoscopies were randomly assigned to the Endocuff group (n=101, 43.6% women) or the standard colonoscopy group (n=99; 57.6% women). One of 2 experienced endoscopists performed the colonoscopies, aiming for a thorough evaluation of the proximal sides of all haustral folds, flexures, and valves in the shortest time possible. Inspection time was measured with a stopwatch and calculated by subtracting washing, suctioning, polypectomy and biopsy times from total withdrawal time. Results There were significantly fewer women in the Endocuff arm (P = .0475) but there were no other demographic differences between groups. Mean insertion time with Endocuff was 4.0 min vs 4.4 min for standard colonoscopy (P = .14). Mean inspection time with Endocuff was 6.5 min vs 8.4 min for standard colonoscopy (P < .0001). Numbers of adenomas detected per colonoscopy (1.43 vs 1.07; P = .07), adenoma detection rate (61.4% vs 52%; P = .21), number of sessile serrated polyps per colonoscopy (0.27 vs 0.21; P = .12), and sessile serrated polyp detection rate (19.8% vs 11.1%; P = .09) were all higher with Endocuff Vision. Results did not differ significantly when we controlled for age, sex, or race. Conclusion In a randomized trial, we found inclusion of Endocuff in screening or surveillance colonoscopies to decrease examination time without reducing lesion detection

    Leydig cells express neural cell adhesion molecules in vivo and in vitro

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    The neural cell adhesion molecule (NCAM) polypeptides are expressed by numerous tissues during embryonic development, where they are involved in cell-cell interactions. In the adult, NCAM expression is confined to a few cell types, including neurons and peptide-hormone-producing cells. Here we demonstrate that the Leydig cells of the adult rat, mouse, and hamster testes express NCAM as well. Western blotting showed that an NCAM of approximately 120 kDa was present in the adult testes of all three species investigated. This form was also found in freshly isolated mouse Leydig cells and in Leydig cells after 2 days in culture. After 4 days in culture, mouse Leydig cells expressed additional NCAM isoforms of approximately 140 and 180 kDa, indicating changes in alternative splicing of NCAM primary transcripts. Also, NCAM mRNA of all isoforms, as detected by S1-nuclease protection assays, increased with time in culture. The expression of the cell adhesion molecule NCAM by adult Leydig cells may explain the aggregation of Leydig cells in clusters in rodent testes, which could be a prerequisite for functional coordination of groups of Leydig cells. Furthermore, the presence of this neural and endocrine marker may indicate a closer relationship between Leydig cells and neural and peptide-hormone-producing cells than is considered to exist at the present time

    The Dynamic Nature of Eukaryotic Genomes

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    Analyses of diverse eukaryotes reveal that genomes are dynamic, sometimes dramatically so. In numerous lineages across the eukaryotic tree of life, DNA content varies within individuals throughout life cycles and among individuals within species. Discovery of examples of genome dynamism is accelerating as genome sequences are completed from diverse eukaryotes. Though much is known about genomes in animals, fungi, and plants, these lineages represent only 3 of the 60-200 lineages of eukaryotes. Here, we discuss diverse genomic strategies in exemplar eukaryotic lineages, including numerous microbial eukaryotes, to reveal dramatic variation that challenges established views of genome evolution. For example, in the life cycle of some members of the radiolaria, ploidy increases from haploid (N) to approximately 1,000N, whereas intrapopulation variability of the enteric parasite Entamoeba ranges from 4N to 40N. Variation has also been found within our own species, with substantial differences in both gene content and chromosome lengths between individuals. Data on the dynamic nature of genomes shift the perception of the genome from being fixed and characteristic of a species (typological) to plastic due to variation within and between species

    Major transitions in human evolution.

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    Evolutionary problems are often considered in terms of 'origins', and research in human evolution seen as a search for human origins. However, evolution, including human evolution, is a process of transitions from one state to another, and so questions are best put in terms of understanding the nature of those transitions. This paper discusses how the contributions to the themed issue 'Major transitions in human evolution' throw light on the pattern of change in hominin evolution. Four questions are addressed: (1) Is there a major divide between early (australopithecine) and later (Homo) evolution? (2) Does the pattern of change fit a model of short transformations, or gradual evolution? (3) Why is the role of Africa so prominent? (4) How are different aspects of adaptation-genes, phenotypes and behaviour-integrated across the transitions? The importance of developing technologies and approaches and the enduring role of fieldwork are emphasized.This article is part of the themed issue 'Major transitions in human evolution'

    Caracterização física das chapas de partículas com os rejeitos oriundos da cana-de-açúcar e das folhas de bambu

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    A problemática do descarte correto dos resíduos sólidos gerados nos diferentes processos industriais faz parte das questões ambientais discutidas na atualidade. Nesse sentido, este trabalho visa estabelecer uma nova alternativa na disposição final de dois rejeitos por meio da produção compósitos para chapas de partículas e, a avaliação das propriedades físicas. O enfoque foi dado à reutilização do bagaço da cana-de-açúcar, originário do processamento da Saccharum officinarum, resíduo oriundo da usina Paraíso Bioenergia, produtora de açúcar e álcool, localizada no município de Torrinha-SP; além das folhas caulinares do bambu da espécie Dendrocalamus giganteus. Para tanto, foram produzidas chapas em seis diferentes tratamentos – 100%, 75%, 50%, 40%, 25% e 0% de bagaço de cana, em relação à massa total dos compósitos, sendo completadas com as folhas de bambu trituradas. Tais chapas foram produzidas e distinguidas por meio de ensaios normalizados da norma NBR 14.810-3 (2002), nas quais foram determinados os coeficientes de teor de umidade (variação de 8,8% a 11,94%) e, absorção (56,3% a 71,3%) e massa específica (0,69 g/cm3 a 0,74 g/cm3).In present days, the disposition of solid residues generated in industrial processes is one of the most important environment questions. In this context, the aim of this work is to establish an alternative to employ these residues, producing particleboards, and evaluation of physical property. The mean focus of the word is reusing: sugar cane bagasse, from processing Saccharum officinarum in Paraíso Bioenergia plant (Torrinha, SP), that produces sugar and ethanol; and caulinar leaves of bamboo Dendrocalamus giganteus. Particleboards were produced in six different insume fractions: 100%, 75%, 50%, 40%, 25% e 0% (sugar cane bagasse) related to total composite mass, completed with bamboo caulinar leaves. The panels were evaluated using normative recommendations from NBR14810-3 (2002) to determine moisture content (ranging from 8.8 % to 11.9%), water absorption (56,3 % to 71,3 %), and density (0,69 g/cm3 to 0,74g/cm3

    Are Microbes Fundamentally Different Than Macroorganisms? Convergence and a Possible Case for Neutral Phenotypic Evolution in Testate Amoeba (Amoebozoa: Arcellinida)

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    This study reveals extensive phenotypic convergence based on the non-monophyly of genera and morphospecies of testate (shelled) amoebae. Using two independent markers, small subunit ribosomal DNA (ssu-rDNA) and mitochondrial cytochrome oxidase I (COI), we demonstrate discordance between morphology and molecules for ‘core Nebela’ species (Arcellinida; Amoebozoa). Prior work using just a single locus, ssu-rDNA, also supported the non-monophyly of the genera Hyalosphenia and Nebela as well as for several morphospecies within these genera. Here, we obtained COI gene sequences of 59 specimens from seven morphospecies and ssu-rDNA gene sequences of 50 specimens from six morphospecies of hyalosphenids. Our analyses corroborate the prior ssu-rDNA findings of morphological convergence in test (shell) morphologies, as COI and ssu-rDNA phylogenies are concordant. Further, the monophyly of morphospecies is rejected using approximately unbiased tests. Given that testate amoebae are used as bioindicators in both palaeoecological and contemporary studies of threatened ecosystems such as bogs and fens, understanding the discordance between morphology and genetics in the hyalosphenids is essential for interpretation of indicator species. Further, while convergence is normally considered the result of natural selection, it is possible that neutrality underlies phenotypic evolution in these microorganisms
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