180 research outputs found

    The Swift X-Ray Te1escope: Status and Performance

    Get PDF
    We present science highlights and performance from the Swift X-ray Telescope (XRT), which was launched on November 20,2004. The XRT covers the 0.2-10 keV band, and spends most of its time observing gamma-ray burst (GRB) afterglows, though it has also performed observations of many other objects. By mid-August 2007, the XRT had observed over 220 GRB afterglows, detecting about 96% of them. The XRT positions enable followup ground-based optical observations, with roughly 60% of the afterglows detected at optical or near IR wavelengths. Redshifts are measured for 33% of X-ray afterglows. Science highlights include the discovery of flaring behavior at quite late times, with implications for GRB central engines; localization of short GRBs, leading to observational support for compact merger progenitors for this class of bursts; a mysterious plateau phase to GRB afterglows; as well as many other interesting observations such as X-ray emission from comets, novae, galactic transients, and other objects

    Effects of d-α-Tocopherol and Dietary Energy on Growth and Health of Pre-Ruminant Dairy Calves

    Get PDF
    Newborn Holstein bull calves were fed milk to support low or moderate growth and were supplemented with a complement of vitamins A, D, and E. The objective of the study was to determine the effects of dietary energy and vitamin supplementation on inflammation at the whole-body level. Calves were assigned randomly to one of four treatment groups (low growth, not vitamin supplemented; low growth, vitamin supplemented; moderate growth, not vitamin supplemented; moderate growth, vitamin supplemented) for five weeks. Vitamin supplementation tended to improve average daily gain in moderate-growth calves and significantly increased concentrations of retinol, 25-(OH)-vitamin D, and α-tocopherol in plasma in supplemented groups. Moderate growth calves exhibited lower concentrations of α-tocopherol in plasma and higher concentrations of serum haptoglobin, which is a protein associated with chronic inflammation. All calves exhibited elevated concentrations of the more acute indicator of inflammation, serum amyloid A, during weeks 1-3. These results indicate potential roles for vitamins A, D, and E in moderation of pro-inflammatory responses early in life

    Does congenital deafness affect the structural and functional architecture of primary visual cortex?

    Get PDF
    Deafness results in greater reliance on the remaining senses. It is unknown whether the cortical architecture of the intact senses is optimized to compensate for lost input. Here we performed widefield population receptive field (pRF) mapping of primary visual cortex (V1) with functional magnetic resonance imaging (fMRI) in hearing and congenitally deaf participants, all of whom had learnt sign language after the age of 10 years. We found larger pRFs encoding the peripheral visual field of deaf compared to hearing participants. This was likely driven by larger facilitatory center zones of the pRF profile concentrated in the near and far periphery in the deaf group. pRF density was comparable between groups, indicating pRFs overlapped more in the deaf group. This could suggest that a coarse coding strategy underlies enhanced peripheral visual skills in deaf people. Cortical thickness was also decreased in V1 in the deaf group. These findings suggest deafness causes structural and functional plasticity at the earliest stages of visual cortex

    Environmental indicators of recharge to basement aquifers of Tanzania

    Get PDF
    One of the main uncertainties surrounding the impact of climate change in Africa is its effect on water supplies. Adding to this uncertainty is a lack of information on recharge to the weathered basement aquifers and how these aquifers respond to rainfall and abstraction. Residence time indicators (such as CFCs) which can indicate the amount of modern recharge in abstracted groundwater, can be a helpful first step in identifying whether active recharge is occurring. Simple chloride balance techniques are also useful to provide an indication of the proportion of recharge. We report the results of using these environmental indicators in the Singida area of Central Tanzania as part of a wider study of groundwater chemistry in the basement aquifers

    STRAIN DIFFERENCES IN THE EXPRESSION OF THE EPA-1-RESTRICTING ELEMENT

    Full text link
    Epa-1-specific cytotoxic T lymphocytes (CTL) lyse epidermal cells (EC) of different Epa-1 + H-2 k strains, such as AKR, CBA, C58, and RF, at different levels. We used an H-2K k -specific monoclonal antibody (mAb) to test the hypothesis that this phenomenon is due to differences in the H-2-restricting element. Initially, we established the specificity of this mAb for the Epa-1-restricting element by demonstrating its capacity to inhibit the lysis of CBA EC by Epa-1-specific CTL. We then used it as the probe in a cellular radioimmunoassay to quantify the expression of the restricting element by EC of different H-2 k strains. We found that C58 and RF EC bound significantly less of the mAb than did CBA EC. Although AKR also bound less of the mAb than did CBA EC, the difference was not statistically significant. To examine the generality of this phenomenon, we quantified the expression of K k antigens on spleen cells (SC) of the same four strains. We found that RF SC, but not AKR or C58 SC, bound significantly less of the K k mAb than did CBA SC. Thus, the differential CTL lysis of Epa-1 + EC of different strains probably reflects differences in expression of the H-2-restricting element rather than of the nominal antigen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75485/1/j.1744-313X.1987.tb00375.x.pd

    Excavation of an early 17th-century glassmaking site at Glasshouse, Shinrone, Co. Offaly, Ireland

    Get PDF
    An archaeological research excavation was conducted in the area immediately surrounding an upstanding glassmaking furnace near Shinrone, Co. Offaly, Ireland. It dates to the early to mid 17th century and was built and operated by French Huguenots, probably de Hennezells (de Hennezel/Henzeys/Hensie) who had settled in this region as part of the Crown plantation of King’s County (now Co. Offaly). This furnace, which employed wood rather than coal as a fuel, is a very rare survival, with no other upstanding examples known in Ireland, Britain or the Lorraine region of France where the form probably originated

    Confiança na polícia em Minas Gerais: o efeito da percepção de eficiência e do contato individual

    Full text link
    O artigo busca identificar e analisar os principais fatores que impactam a confiança na polícia em Minas Gerais. Utilizou-se a pesquisa "Vitimização e Percepção de Medo em Belo Horizonte e Minas Gerais" de 2009, aplicada em 29 municípios. Além de Belo Horizonte, abrangeu 5 cidades da Região Metropolitana, 7 cidades consideradas polos regionais e 16 municípios com população inferior a 10 mil habitantes. Os resultados mostram que indivíduos confundem funções do trabalho policial com as do sistema de justiça criminal. O contato com a polícia reduz a confiança, especialmente quando ele é iniciado por policiais. Nas cidades menores, onde a polícia é mais próxima dos cidadãos e a criminalidade é menor, a polícia recebe mais confiança do que nas maiores. A percepção de eficiência em solucionar problemas relacionados à violência é a variável que produz maior efeito positivo no nível de confiança que a instituição recebe
    corecore