21,794 research outputs found

    Enhanced LANDSAT images of Antarctica and planetary exploration

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    Since early in the LANDSAT program, black-and-white paper prints of band 7 (near infrared) of the LANDSAT multispectral scanner have been used extensively to prepare semicontrolled maps of Antarctica. Image-processing techniques are now employed to enhance fine detail and to make controlled image-mosaic maps in color. LANDSAT multispectral images of Antarctica help to expand our knowledge of extraterrestrial bodies by showing bare-ice areas as bright blue patches; on such patches meteorites tend to be concentrated and are collected. Many subtle flow features in Antarctic ice streams resemble features at the mouths of Martian outflow channels, which suggests that the channels also contained ice. Furthermore, flow lines in Antarctic ice sheets that merge with ice shelves resemble Martian flow features associated with dissected terrain along the Martian northern highland margin, and support the concept that ice was involved in the transport of material from the southern highlands to the northern lowland plains. In Antarctica, as on Mars, the virtual absence of fluvial activity over millions of years has permitted the growth of glacial and eolian features to unusually large sizes

    The use of remote sensing in solving Florida's geological and coastal engineering problems

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    LANDSAT imagery and NASA high altitude color infrared (CIR) photography were used to select suitable sites for sanitary landfill in Volusia County, Florida and to develop techniques for preventing sand deposits in the Clearwater inlet. Activities described include the acquisition of imagery, its analysis by the IMAGE 100 system, conventional photointerpretation, evaluation of existing data sources (vegetation, soil, and ground water maps), site investigations for ground truth, and preparation of displays for reports

    Boundary crossing Random Walks, clinical trials and multinomial sequential estimation

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    A sufficient condition for the uniqueness of multinomial sequential unbiased estimators is provided generalizing a classical result for binomial samples. Unbiased estimators are applied to infer the parameters of multidimensional or multinomial Random Walks which are observed until they reach a boundary. An application to clinical trials is presented

    Framed to fit? Challenging the domestic abuse ‘story’ in child protection

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    The current framing of domestic violence generates profound problems for those concerned with supporting change for all involved. In particular, the stress on the ‘equal vulnerability’ of all women to domestic abuse, irrespective of economic or social circumstances, is out of line with a developing evidence base and deprives policymakers and practitioners of the conceptual tools that are needed to situate actual identities, choices and challenges with differing implications for women as well as men. In this article, we note the relative lack of attention in the UK to the work of international researchers on how gendered inequalities intersect with those arising from a range of others, crucially, class and ‘race’. This body of work also draws attention to the importance of understanding the impact of state interventions on marginalised communities, an area also neglected in the UK

    The allometric relationship between mean fibre diameter of mohair and the fleece-free liveweight of Angora goats over their lifetime

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    As mean fibre diameter (MFD) is the primary determinant of mohair price we aimed to quantify the lifetime changes in mohair MFDas Angora goats aged and grew. Measurements were made over 12 shearing periods on a population of Angora goats representing the current range and diversity of genetic origins including South African, Texan and interbred admixtures of these and Australian sources. Records of sire, dam, birthweight, birth parity, liveweight, fleece growth and fleece quality were taken for does and castrated males (wethers) (n = 267 animals). Fleece-free liveweights (FFLwt) were determined for each goat at shearing time by subtracting the greasy fleece weight from the liveweight recorded immediately before shearing. A restricted maximum likelihood growth curve model was developed for relating MFD to FFLwt, age and other measurements.Asimple way of describing the results is:MFD= k (FFLwt)b E; where k is a parameter that can vary in a systematic way with shearing(age), breed, weaning weight, sire, dam and individual; b is a parameter that is the same for nearly the whole study; and E are independent errors from a log-normal distribution. The analysis shows that ^b = 0.34, with s.e. (^b) = 0.021. Thus, mohair MFD was allometrically related to the cube root of FFLwt over the lifetime of Angora goats. However, the allometric proportionality constant differed in a systematic way with age at shearing, genetic strain, weaning weight, sire, dam and individual. For Texan-breed goats, MFD decreased as weaning weight increased (P = 0.00016). The findings indicate that management factors that affect liveweight and weaning weight have lifetime effects on mohair fibre diameter and therefore the value of mohair and the profitability of the mohair enterprise.<br /

    The Star-Forming Dwarf Galaxy Populations of two z ~ 0.4 Clusters: MS1512.4+3647 and Abell 851

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    We present the results of a deep narrow-band [OII] 3727 \AA emission-line search for faint (g<g < 27), star-forming galaxies in the field of the z=0.37z=0.37 MS1512.4+3647 cluster. We find no evidence for an over-density of emission-line sources relative to the field at z∼z \sim 0.4 (Hogg et al. 1998), and therefore conclude that the MS1512.4+3647 sample is dominated by field [OII] emission-line galaxies which lie along the ∼\sim 180 Mpc line of sight immediately in front and behind the cluster. This is surprising, given that the previously surveyed z=0.41z=0.41 cluster Abell 851 has 3-4 times the field emission-line galaxy density (Martin et al. 2000). We find that the MS1512.4+3647 sample is deficient in galaxies with intermediate colors (1.0 <g−i<< g-i < 2.0) and implied star-formation exponential decay timescales τ∼\tau \sim 100 Myr - 1 Gyr that dominate the Abell 851 emission-line galaxy population. Instead, the majority of [OII] emission-line galaxies surrounding the MS1512.4+3647 cluster are blue (g−i≤1.0g-i \leq 1.0) and forming stars in bursts with τ<\tau < 100 Myr. In both samples, galaxies with the shortest star-formation timescales are preferentially among the faintest star-forming objects. Their i luminosities are consistent with young stellar populations \sim 10^8 - 10^9 \Msun, although an additional factor of ten in stellar mass could be hiding in underlying old stellar populations. We discuss the implications for the star-formation histories of dwarf galaxies in the field and rich clusters.Comment: 26 pages, including 5 tables and 13 figures; accepted for publication in the Astrophysical Journa

    Spin-dependent phenomena and device concepts explored in (Ga,Mn)As

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    Over the past two decades, the research of (Ga,Mn)As has led to a deeper understanding of relativistic spin-dependent phenomena in magnetic systems. It has also led to discoveries of new effects and demonstrations of unprecedented functionalities of experimental spintronic devices with general applicability to a wide range of materials. In this article we review the basic material properties that make (Ga,Mn)As a favorable test-bed system for spintronics research and discuss contributions of (Ga,Mn)As studies in the general context of the spin-dependent phenomena and device concepts. Special focus is on the spin-orbit coupling induced effects and the reviewed topics include the interaction of spin with electrical current, light, and heat.Comment: 47 pages, 41 figure
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