216 research outputs found

    Diurnal fluctuation in the number of hypocretin/orexin and histamine producing: Implication for understanding and treating neuronal loss.

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    The loss of specific neuronal phenotypes, as determined by immunohistochemistry, has become a powerful tool for identifying the nature and cause of neurological diseases. Here we show that the number of neurons identified and quantified using this method misses a substantial percentage of extant neurons in a phenotype specific manner. In mice, 24% more hypocretin/orexin (Hcrt) neurons are seen in the night compared to the day, and an additional 17% are seen after inhibiting microtubule polymerization with colchicine. We see no such difference between the number of MCH (melanin concentrating hormone) neurons in dark, light or colchicine conditions, despite MCH and Hcrt both being hypothalamic peptide transmitters. Although the size of Hcrt neurons did not differ between light and dark, the size of MCH neurons was increased by 15% in the light phase. The number of neurons containing histidine decarboxylase (HDC), the histamine synthesizing enzyme, was 34% greater in the dark than in the light, but, like Hcrt, cell size did not differ. We did not find a significant difference in the number or the size of neurons expressing choline acetyltransferase (ChAT), the acetylcholine synthesizing enzyme, in the horizontal diagonal band (HBD) during the dark and light conditions. As expected, colchicine treatment did not increase the number of these neurons. Understanding the function and dynamics of transmitter production within "non-visible" phenotypically defined cells has fundamental implications for our understanding of brain plasticity

    Estimating The Economic Impact Of Local Cultural Organizations: The Charlotte Arts & Science Council Example

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    This paper details the impact of the 58 affiliated members of the Charlotte Arts & Science Council on the economy of Mecklenburg County, North Carolina. We find that the affiliated members of the Arts & Science Council had a sizable impact on the Mecklenburg economy.  Output was expanded by 129,171,622;earningswereincreasedby129,171,622; earnings were increased by 50,589,999; and employment was increased by 2,132 full-time equivalent jobs.  These economic impacts were an important addition to the rich and varied cultural offerings provided by the Arts & Science Council affiliates

    Evidence for field enhanced electron capture by EL2 centers in semiā€insulating GaAs and the effect on GaAs radiation detectors

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    The performance of Schottky contact semiconductor radiation detectors fabricated from semiā€insulating GaAs is highly sensitive to charged impurities and defects in the material. The observed behavior of semiā€insulating GaAs Schottky barrier alpha particle detectors does not match well with models that treat the semiā€insulating material as either perfectly intrinsic or as material with deep donors (EL2) of constant capture cross section compensated with shallow acceptors. We propose an explanation for the discrepancy based on enhanced capture of electrons by EL2 centers at high electric fields and the resulting formation of a quasineutral region in the GaAs. Presented is a simple model including field enhanced electron capture which shows good agreement with experimental alpha particle pulse height measurements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71231/2/JAPIAU-75-12-7910-1.pd

    Natural Sleep and Its Seasonal Variations in Three Pre-Industrial Societies

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    How did humans sleep before the modern era? Because the tools to measure sleep under natural conditions were developed long after the invention of the electric devices suspected of delaying and reducing sleep, we investigated sleep in three preindustrial societies[1ā€“3]. We find that all three show similar sleep organization, suggesting that they express core human sleep patterns, likely characteristic of pre-modern era Homo sapiens. Sleep periods, the times from onset to offset, averaged 6.9ā€“8.5-h, with sleep durations of 5.7ā€“7.1-h, amounts near the low end of those industrial societies[4ā€“7]. There was a difference of nearly 1-h between summer and winter sleep. Daily variation in sleep duration was strongly linked to time of onset, rather than offset. None of these groups began sleep near sunset, onset occurring, on average, 3.3-h after sunset. Awakening was usually before sunrise. The sleep period consistently occurred during the nighttime period of falling environmental temperature, was not interrupted by extended periods of waking and terminated, with vasoconstriction, near the nadir of daily ambient temperature. The daily cycle of temperature change, largely eliminated from modern sleep environments, may be a potent natural regulator of sleep. Light exposure, was maximal in the morning greatly decreasing at noon, indicating that all three groups seek shade at midday and that light activation of the suprachiasmatic nucleus is maximal in the morning. Napping occurred on \u3c7% of days in winter and \u3c22% of days in summer. Mimicking aspects of the natural environment might be effective in treating certain modern sleep disorders

    Childrenā€™s language abilities predict success in remote communication contexts

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    Remote communicative contexts are part of everyday social, familial, and academic interactions for the modern child. We investigated the ability of second-graders to engage in remote discourse, and we determined which of several abilitiesā€”language, theory of mind, and temperamentā€”predicted their success. Fifty 7-to-9-year-old monolingual English speakers with a wide range of language abilities participated in standardized testing and an expository discourse task in which they taught two adults to solve the Tower of London, one in simulated video chat and a second in a simulated phone condition. The discourse was scored for the inclusion of 15 items deemed relevant to the explanation. Children included from 27% to 87% of the items. They communicated more information via gesture than spoken word in both conditions. They included more spoken information in the phone condition than the video condition and more information overall in the phone condition. Performance was positively associated with spoken language ability. There was no relationship between performance and theory of mind, temperament, ability to solve the Tower of London, age, or sex. We conclude that 7-to-9-year-olds adjust the modality and content of their message to suit their remote partner's needs, but their success in remote discourse contexts varies greatly from individual to individual. Children with below-average language skills are at risk for functional impairments in remote communication

    Evidence for field enhanced electron capture by EL2 centers in semi-insulating GaAs and the effect on GaAs radiation detectors

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    The performance of Schottky contact semiconductor radiation detectors fabricated from semi-insulating GaAs is highly sensitive to charged impurities and defects in the material. The observed behavior of semi-insulating GaAs Schottky barrier alpha particle detectors does not match well with models that treat the semi-insulating material as either perfectly intrinsic or as material with deep donors (EL2) of constant capture cross section compensated with shallow acceptors. We propose an explanation for the discrepancy based on enhanced capture of electrons by EL2 centers at high electric fields and the resulting formation of a quasineutral region in the GaAs. Presented is a simple model including field enhanced electron capture which shows good agreement with experimental alpha particle pulse height measurements

    Clinical characteristics and outcome of pauci-immune glomerulonephritis in African Americans

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    Pauci-immune glomerulonephritis is rare in African Americans (AA) and the clinical presentation and treatment outcomes of vasculitis have not been well described
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