512 research outputs found

    Low power, compact charge coupled device signal processing system

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    A variety of charged coupled devices (CCDs) for performing programmable correlation for preprocessing environmental sensor data preparatory to its transmission to the ground were developed. A total of two separate ICs were developed and a third was evaluated. The first IC was a CCD chirp z transform IC capable of performing a 32 point DFT at frequencies to 1 MHz. All on chip circuitry operated as designed with the exception of the limited dynamic range caused by a fixed pattern noise due to interactions between the digital and analog circuits. The second IC developed was a 64 stage CCD analog/analog correlator for performing time domain correlation. Multiplier errors were found to be less than 1 percent at designed signal levels and less than 0.3 percent at the measured smaller levels. A prototype IC for performing time domain correlation was also evaluated

    Leukotriene C4 biosynthesis in isolated August rat peritoneal leukocytes

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    The mixed leukocyte population obtained from the peritoneum of the August rat is a potentially important experimental model of inherent eosinophilia that has not been well characterized. In the present study, isolated cell preparations generated a concentration-dependent release of leukotriene (LT) C4 when exposed to the Ca2+ ionophore A23187, reaching maximal stimulation at 5.0 μM. This response was inhibited by the 5-lipoxygenase activating protein antagonist MK-886 (0.1 μM), nominally Ca2+ and Mg2+-free incubation media and by activation of protein kinase C via phorbol 12-myristate 13-acetate (50 nM). These findings establish a model system for investigating LTC4 profiles contingent with innate peritoneal eosinophilia and are consistent with the hypothesis that cellular LTC4 biosynthesis is phosphoregulated

    Applying a community entrepreneurship development (CED) framework

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    This article develops a community entrepreneurship development (CED) framework and illustrates its use in a case study of the current and potential value of agriculture to the Barossa Valley in South Australia. The CED offers a framework for rural regional development that both practitioners and policymakers can use to develop and leverage entrepreneurial competencies and other forms of community capital to foster entrepreneurship at the community level. It assesses the potential for leveraging Emery and Flora’s [(2006). Spiraling-up: Mapping community transformation with community capitals framework. Community Development, 37(1), 19–35] community capital framework to build entrepreneurship and innovation. The findings suggest that the success of firm-level entrepreneurship is often dependent upon leveraging the rural region’s idiosyncratic natural capitals with human and social/entrepreneurial capitals to result in community-level entrepreneurial market development initiatives

    A Conserved Bicycle Model for Circadian Clock Control of Membrane Excitability

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    SummaryCircadian clocks regulate membrane excitability in master pacemaker neurons to control daily rhythms of sleep and wake. Here, we find that two distinctly timed electrical drives collaborate to impose rhythmicity on Drosophila clock neurons. In the morning, a voltage-independent sodium conductance via the NA/NALCN ion channel depolarizes these neurons. This current is driven by the rhythmic expression of NCA localization factor-1, linking the molecular clock to ion channel function. In the evening, basal potassium currents peak to silence clock neurons. Remarkably, daily antiphase cycles of sodium and potassium currents also drive mouse clock neuron rhythms. Thus, we reveal an evolutionarily ancient strategy for the neural mechanisms that govern daily sleep and wake

    Cellular Angiofibroma of Oral Mucosa: Report of Two Cases

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    Cellular angiofibroma is a benign vascular neoplasm that typically arises in the vulva, perineal, and paratesticular region. Microscopically the lesions exhibit multiple small, non-dilated capillary channels, many of which contain erythrocytes. The endothelial lining cells are prominent, with monomorphic oval nuclei. Interposed among the vessels are both delicate and mature collagen fibers with fibroblastic hypercellularity that is variable in older lesions where sclerosis is prominent. The lesions usually do not recur following simple excision. Recent evidence indicates that cellular angiofibromas may be cytogenetically related to spindle cell lipoma. This represents the first reported instances of cellular angiofibroma in the oral cavity

    The Central Clock Neurons Regulate Lipid Storage in Drosophila

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    A proper balance of lipid breakdown and synthesis is essential for achieving energy homeostasis as alterations in either of these processes can lead to pathological states such as obesity. The regulation of lipid metabolism is quite complex with multiple signals integrated to control overall triglyceride levels in metabolic tissues. Based upon studies demonstrating effects of the circadian clock on metabolism, we sought to determine if the central clock cells in the Drosophila brain contribute to lipid levels in the fat body, the main nutrient storage organ of the fly. Here, we show that altering the function of the Drosophila central clock neurons leads to an increase in fat body triglycerides. We also show that although triglyceride levels are not affected by age, they are increased by expression of the amyloid-beta protein in central clock neurons. The effect on lipid storage seems to be independent of circadian clock output as changes in triglycerides are not always observed in genetic manipulations that result in altered locomotor rhythms. These data demonstrate that the activity of the central clock neurons is necessary for proper lipid storage

    Mobilizing Crop Biodiversity

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    Over the past 70 years, the world has witnessed extraordinary growth in crop productivity, 1 enabled by a suite of technological advances, including higher yielding crop varieties, improved farm management, synthetic agrochemicals, and agricultural mechanization. While this “Green Revolution” intensified crop production, and is credited with reducing famine and malnutrition, its benefits were accompanied by several undesirable collateral effects (Pingali, 2012). These include a narrowing of agricultural biodiversity, stemming from increased monoculture and greater reliance on a smaller number of crops and crop varieties for the majority of our calories. This reduction in diversity has created vulnerabilities to pest and disease epidemics, climate variation, and ultimately to human health (Harlan, 1972). The value of crop diversity has long been recognized (Vavilov, 1992). A global system of genebanks (e.g.www.genebanks.org/genebanks/) was established in the 1970s to preserve the abundant genetic variation found in traditional “landrace” varieties of crops and in crop wild relatives (Harlan, 1972). While preserving crop variation is a critical first step, the time has come to make use of this variation to breed more resilient crops. The DivSeek International Network (https://divseekintl.org/) is a scientific, not-for profit organization that aims to accelerate such effort

    Overview of the Alliance for Cellular Signaling

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    The Alliance for Cellular Signaling is a large-scale collaboration designed to answer global questions about signalling networks. Pathways will be studied intensively in two cells-B lymphocytes (the cells of the immune system) and cardiac myocytes-to facilitate quantitative modelling. One goal is to catalyse complementary research in individual laboratories; to facilitate this, all alliance data are freely available for use by the entire research community.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62977/1/nature01304.pd

    Historical analysis of the Brazilian cervical cancer screening program from 2006 to 2013: a time for reflection

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    BACKGROUND: The Cervical Cancer Database of the Brazilian National Health Service (SISCOLO) contains information regarding all cervical cytological tests and, if properly explored, can be used as a tool for monitoring and managing the cervical cancer screening program. The aim of this study was to perform a historical analysis of the cervical cancer screening program in Brazil from 2006 to 2013. MATERIAL AND METHODS: The data necessary to calculate quality indicators were obtained from the SISCOLO, a Brazilian health system tool. Joinpoint analysis was used to calculate the annual percentage change. RESULTS: We observed important trends showing decreased rates of low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL) and an increased rate of rejected exams from 2009 to 2013. The index of positivity was maintained at levels below those indicated by international standards; very low frequencies of unsatisfactory cases were observed over the study period, which partially contradicts the low rate of positive cases. The number of positive cytological diagnoses was below that expected, considering that developed countries with low frequencies of cervical cancer detect more lesions annually. CONCLUSIONS: The evolution of indicators from 2006 to 2013 suggests that actions must be taken to improve the effectiveness of cervical cancer control in Brazil
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