709 research outputs found

    Emissivity coatings for low-temperature space radiators Quarterly progress report, 1 Jan. - 31 Mar. 1966

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    Solar absorptance and emittance of candidate zinc oxides/silicone and zinc oxide/potassium silicate coatings measured at room temperature for application to space radiator

    Emissivity coatings for low-temperature space radiators Quarterly progress report, 1 Jul. - 30 Sep. 1966

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    Low solar absorption emissivity coatings for low temperature spacecraft radiators - ultraviolet radiation test

    Emissivity coatings for low-temperature space radiators Quarterly progress report, 10 Oct. - 31 Dec. 1966

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    Evaluation of aluminum silicate - potassium silicate, and zinc oxide - potassium silicate emissive coatings for spacecraft radiator

    Associations between developmental changes in errorā€related brain activity and executive functions in early childhood

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    Behavioral evidence indicates that skills associated with childrenā€™s cognitive control (e.g., response inhibition and attentional control) undergo rapid development during early childhood. A particularly important time is the transition to elementary school. Yet, at present, relatively little is known about developmental changes in the brain processes linked to cognitive control during this period, including those associated with error monitoring, including the errorā€related negativity (ERN) and the error positivity (Pe). Moreover, understanding how ERP correlates of cognitive control relate to behavioral measures of these skills over time is also limited. In the present study, repeated assessments of 4ā€ to 6ā€yearā€old childrenā€™s (Nā€‰=ā€‰49, mean ageā€‰=ā€‰5 years 10 months) performance on a go/noā€go task were collected to examine developmental changes in error processing and response inhibition across 6 months. Data revealed the presence of both the ERN and Pe at each time point, but also showed individual differences in the testā€retest associations for each component. Behavioral changes in response inhibition on the go/noā€go task and a standardized measure of attentional control were associated with changes in electrophysiological measures of error processing. Additional analyses comparing children of the same age who had completed the go/noā€go task once to those who participated longitudinally revealed that, with repeated assessments, children exhibited behavioral changes in performance that could be attributed to both development and to the effects of practice, such as strategic accommodation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142529/1/psyp13040.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142529/2/psyp13040_am.pd

    Surface characterization of selected LDEF tray clamps

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    The surface characterization of chromic acid anodized 6061-T6 aluminum alloy tray clamps has shown differences in surface chemistry depending upon the position on the Long Duration Exposure Facility (LDEF). Water contact angle results showed no changes in wettability of the tray clamps. The overall surface topography of the control, trailing edge(E3) and leading edge(D9) samples was similar. The thickness of the aluminum oxide layer for all samples determined by Auger depth profiling was less than one micron. X-ray photoelectron spectroscopy (XPS) analysis of the tray clamps showed significant differences in the surface composition. Carbon and silicon containing compounds were the primary contaminants detected

    \u3ci\u3eArgulus\u3c/i\u3e From the Pascagoula River, MS, USA, With an Emphasis On Those of the Threatened Gulf Sturgeon, \u3ci\u3eAcipenser oxyinchus desotoi\u3c/i\u3e

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    Species of Argulus (Branchiura Thorell, 1864) are common ectoparasites of freshwater, estuarine, and marine fishes. Argulid identification and taxonomy is often confusing because many species are reported to parasitize multiple host species, have similar morphological characters, and come from various salinity regimes. Gulf sturgeon is an anadromous fish natal to drainages in the north-central Gulf of Mexico, and as with many endangered species, has a poorly documented parasite community. During Gulf sturgeon tagging and monitoring studies (2016ā€“2019) in the Pascagoula River, MS, USA, species of Argulus were collected from Gulf sturgeon as well as other incidentally captured fishes. Argulus flavescens Wilson, 1916 was found on Gulf sturgeon and flathead catfish, Argulus americanus Wilson, 1902 on bowfin, and Argulus bicolor Bere, 1936 on Atlantic stingray. We provide morphological details and measurements for these species as well as the first confirmed 28S rDNA molecular data. Argulus flavescens was more abundant and prevalent on larger Gulf sturgeon and on sturgeon captured in freshwater rather than estuarine habitats. Our results indicate that A. flacescens may not tolerate estuarine salinities and that the anadromous life-history pattern of Gulf sturgeon could help rid them of A. flavescens when they emigrate from their riverine habitats
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