2,695 research outputs found

    Preparatory studies of zero-g cloud drop coalescence experiment

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    Experiments to be performed in a weightless environment in order to study collision and coalescence processes of cloud droplets are described. Rain formation in warm clouds, formation of larger cloud drops, ice and water collision processes, and precipitation in supercooled clouds are among the topics covered

    An inertial velocity reference for the NASA airborne Doppler lidar

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    The following four tasks were studied: (1) modification of the calibration routines to calibrate the Inertial Measurement Unit gyroscope drifts with fixed platform heading; (2) modification of the calibration routines to calibrate the Inertial Measurement Unit accelerometers; (3) checking overall software again for errors; and (4) providing documentation on the above work describing changes to the present software, results of these changes and future operating procedures

    Evaluation of data obtained from atmospheric laser Doppler velocimeter

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    The Doppler lidar velocimeter produces a variety of kinds of data. Besides the line of sight velocity components, there are the reflected amplitudes and the Doppler widths. Computer graphics software for displaying these data was produced. Different methods of presentation are needed for the various items. A picture was produced as pictures are often the best way to gain understanding. The individual lidar scans form a crosshatch pattern. Thus one-dimensional measurements fit together to form a two-dimensional whole. A pair of velocity measurements at a point combine to form a wind measurement with direction and magnitude. This gives a forest of wind vectors. The goal is to find a recognizable pattern to these trees. Often it is necessary to show only part of the information. That is, show only the wind direction not its magnitude or reduce the wind to streamlines of air flow. In other cases data are reduced to contour plots. Just enough contour lines are included to show the picture described

    The name Ixodes dammini epidemiologically justified.

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    Physical Education and Blood Lipid Concentrations in Children: The LOOK Randomized Cluster Trial

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    BACKGROUND AND OBJECTIVES Elevated blood lipids during childhood are predictive of dyslipidemia in adults. Although obese and inactive children have elevated values, any potentially protective role of elementary school physical education is unknown. Our objective was to determine the effect of a modern elementary school physical education (PE) program on the blood lipid concentrations in community-based children. METHODS In this cluster-randomized controlled trial, 708 healthy children (8.1±0.3 years, 367 boys) in 29 schools were allocated to either a 4-year intervention program of specialist-taught PE (13 schools) or to a control group of the currently practiced PE conducted by generalist classroom teachers. Fasting blood lipids were measured at ages 8, 10, and 12 years and intervention and control class activities were recorded. RESULTS Intervention classes included more fitness work and more moderate and vigorous physical activity than control classes (both p3.36mmol.L(-1),130 mg/dL) was lower in the intervention than control group (14% vs. 23%, p = 0.02). There was also an intervention effect on mean LDL-C across all boys (reduction of 9.6% for intervention v 2.8% control, p = 0.02), but not girls (p = 0.2). The intervention effect on total cholesterol mirrored LDL-C, but there were no detectable 4-year intervention effects on high-density lipoprotein cholesterol or triglycerides. CONCLUSIONS The PE program delivered by specialist teachers over four years in elementary school reduced the incidence of elevated LDL-C in boys and girls, and provides a means by which early preventative practices can be offered to all children. TRIAL REGISTRATION Australia New Zealand Clinical Trial Registry ANZRN12612000027819 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=347799.Sources of funding were The Commonwealth Education Trust (New Zealand House, London, UK) (http://www.commonwealth.org.uk/) and the Canberra Hospital Salaried Staff Specialists Fund (http://healthresearch.anu.edu.au/documents/PPFVACATION/ppf-major-info-2012.pdf). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Star Clusters in Virgo and Fornax Dwarf Irregular Galaxies

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    We present the results of a search for clusters in dwarf irregular galaxies in the Virgo and Fornax Cluster using HST WFPC2 snapshot data. The galaxy sample includes 28 galaxies, 11 of which are confirmed members of the Virgo and Fornax clusters. In the 11 confirmed members, we detect 237 cluster candidates and determine their V magnitudes, V-I colors and core radii. After statistical subtraction of background galaxies and foreground stars, most of the cluster candidates have V-I colors of -0.2 and 1.4, V magnitudes lying between 20 and 25th magnitude and core radii between 0 and 6 pc. Using H-alpha observations, we find that 26% of the blue cluster candidates are most likely HII regions. The rest of the cluster candidates are most likely massive (>10^4 Msol) young and old clusters. A comparison between the red cluster candidates in our sample and the Milky Way globular clusters shows that they have similar luminosity distributions, but that the red cluster candidates typically have larger core radii. Assuming that the red cluster candidates are in fact globular clusters, we derive specific frequencies (S_N) ranging from ~0-9 for the galaxies. Although the values are uncertain, seven of the galaxies appear to have specific frequencies greater than 2. These values are more typical of ellipticals and nucleated dwarf ellipticals than they are of spirals or Local Group dwarf irregulars.Comment: 46 pages, 14 figures, 3 tables, accepted by AJ. Higher quality PS version of entire paper available at http://www.astro.washington.edu/seth/dirr_gcs.htm

    The syrphidae of Minnesota

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    This archival publication may not reflect current scientific knowledge or recommendations

    The invasive guttural toad, Amietophrynus gutturalis

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    Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol)The guttural toad, Amietophrynus gutturalis, Power 1927, is a common toad with a broad geographic range through much of temperate, sub-tropical and tropical southern and central Africa. Introduced to the islands of Mauritius and Reunion in the 1960’s, and subsequently to Cape Town in the 1990’s, the species has become invasive in its extra-limital ranges. Determining the invasion history of a species provides valuable information for conservation biologists and managers and it is fundamentally important for improving our understanding of the underlying processes of biological invasions. This study aimed to determine the source populations of the extra-limital populations from Mauritius and Cape Town. Furthermore, studies investigating genetic diversity and demographics of African Bufonidae are largely absent from the literature. Understanding the evolutionary history of the species may also assist with determining their invasive ability and identifying similar features in other bufonids such as Amietophrynus regularis and A. xeros. Using mtDNA sequence data from the 16S and ND2 markers four geographically distinct clades were identified through Bayesian phylogenies and haplotype networks. However, a spatial analysis of molecular variance (SAMOVA) indicated a grouping structure of three clades. A total of 16 haplotypes were identified from 53 samples for the 16S marker and 22 haplotypes were identified from 43 samples for the ND2 marker. Both the Mauritius and Cape Town invasive populations were found to have originated from the eastern clade. However, they matched the common haplotype from this region which was found across a vast area that spans the KwaZulu-Natal province and into the Mpumulanga and Limpopo provinces. This did not allow for identifying a more precise region for the origin of the founder populations. The presence of haplotypes unique to the Cape Town invasive population, which group with the eastern clade, indicates that there has potentially been more than one introduction event. Demographic analysis revealed a recent population expansion in both the northern (Fs = -2.92) and the eastern clades (Fs = -5.03). Significant genetic variation was found among groups (93.92%), with low variation among populations and among populations within groups. Population pairwise differences were found to be significantly different between all clades except between the central and the southern clade. There was a negligible difference in the genetic diversity of the invasive populations when compared to the eastern clade. The eastern clades’ genetic diversity was low compared to the two other clades and demographic analysis revealed that this region has undergone the most recent population expansion. The negligible difference between the eastern clades’ genetic diversity and both invasive populations indicate that founder effects and genetic bottlenecking should have no impact on the invasive populations.National Research Foundation (NRF

    Paul M. Eide, 1906-1980

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