3,745 research outputs found

    Mojave remote sensing field experiment

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    The Mojave Remote Sensing Field Experiment (MFE), conducted in June 1988, involved acquisition of Thermal Infrared Multispectral Scanner (TIMS); C, L, and P-band polarimetric radar (AIRSAR) data; and simultaneous field observations at the Pisgah and Cima volcanic fields, and Lavic and Silver Lake Playas, Mojave Desert, California. A LANDSAT Thematic Mapper (TM) scene is also included in the MFE archive. TM-based reflectance and TIMS-based emissivity surface spectra were extracted for selected surfaces. Radiative transfer procedures were used to model the atmosphere and surface simultaneously, with the constraint that the spectra must be consistent with field-based spectral observations. AIRSAR data were calibrated to backscatter cross sections using corner reflectors deployed at target sites. Analyses of MFE data focus on extraction of reflectance, emissivity, and cross section for lava flows of various ages and degradation states. Results have relevance for the evolution of volcanic plains on Venus and Mars

    Counseling for Young People and Families Affected by Child Sexual Exploitation and Abuse: A Qualitative Investigation of the Perspective of Young People, Parents, and Professionals

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    Despite growing awareness of the negative impact of child sexual exploitation on young people’s psychological, emotional and relational lives, little is known about how counseling can support young people and their families. The aim of this study was to explore the experience of counseling for young people and parents affected by child sexual exploitation and abuse, with a view to examining what facilitates progress, from the perspective of young people, parents and professionals. In-depth semi-structured interviews were conducted with 10 young people, 8 parents and 7 professionals and were analyzed using thematic analysis. Findings suggest that through counseling, young people experienced affective and relational improvements that were attributed to the process. Characteristics of the counseling relationship that facilitated progress included being able to talk openly in a caring, non-judgmental and unpressurized environment, as well as receiving advice, techniques or solutions within a holistic approach. Facets of service delivery were also highlighted, including the provision of confidentiality, flexibility and consistency, along with a multi-agency approach that promoted engagement. Perceived obstacles to progress included resistance at the outset and service location issues

    The not-so-massive black hole in the microquasar GRS1915+105

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    We present a new dynamical study of the black hole X-ray transient GRS1915+105 making use of near-infrared spectroscopy obtained with X-shooter at the VLT. We detect a large number of donor star absorption features across a wide range of wavelengths spanning the H and K bands. Our 24 epochs covering a baseline of over 1 year permit us to determine a new binary ephemeris including a refined orbital period of P=33.85 +/- 0.16 d. The donor star radial velocity curves deliver a significantly improved determination of the donor semi-amplitude which is both accurate (K_2=126 +/- 1 km/s) and robust against choice of donor star template and spectral features used. We furthermore constrain the donor star's rotational broadening to vsini=21 +/-4 km/s, delivering a binary mass ratio of q=0.042 +/- 0.024. If we combine these new constraints with distance and inclination estimates derived from modelling the radio emission, a black hole mass of M_BH=10.1 +/- 0.6 M_sun is inferred, paired with an evolved mass donor of M_2=0.47 +/- 0.27 M_sun. Our analysis suggests a more typical black hole mass for GRS1915+105 rather than the unusually high values derived in the pioneering dynamical study by Greiner et al. (2001). Our data demonstrate that high-resolution infrared spectroscopy of obscured accreting binaries can deliver dynamical mass determinations with a precision on par with optical studies

    Spaceborne radar observations: A guide for Magellan radar-image analysis

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    Geologic analyses of spaceborne radar images of Earth are reviewed and summarized with respect to detecting, mapping, and interpreting impact craters, volcanic landforms, eolian and subsurface features, and tectonic landforms. Interpretations are illustrated mostly with Seasat synthetic aperture radar and shuttle-imaging-radar images. Analogies are drawn for the potential interpretation of radar images of Venus, with emphasis on the effects of variation in Magellan look angle with Venusian latitude. In each landform category, differences in feature perception and interpretive capability are related to variations in imaging geometry, spatial resolution, and wavelength of the imaging radar systems. Impact craters and other radially symmetrical features may show apparent bilateral symmetry parallel to the illumination vector at low look angles. The styles of eruption and the emplacement of major and minor volcanic constructs can be interpreted from morphological features observed in images. Radar responses that are governed by small-scale surface roughness may serve to distinguish flow types, but do not provide unambiguous information. Imaging of sand dunes is rigorously constrained by specific angular relations between the illumination vector and the orientation and angle of repose of the dune faces, but is independent of radar wavelength. With a single look angle, conditions that enable shallow subsurface imaging to occur do not provide the information necessary to determine whether the radar has recorded surface or subsurface features. The topographic linearity of many tectonic landforms is enhanced on images at regional and local scales, but the detection of structural detail is a strong function of illumination direction. Nontopographic tectonic lineaments may appear in response to contrasts in small-surface roughness or dielectric constant. The breakpoint for rough surfaces will vary by about 25 percent through the Magellan viewing geometries from low to high Venusian latitudes. Examples of anomalies and system artifacts that can affect image interpretation are described

    Supplement: Going the Distance: Mapping Host Galaxies of LIGO and Virgo Sources in Three Dimensions Using Local Cosmography and Targeted Follow-up

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    This is a supplement to the Letter of Singer et al. (https://arxiv.org/abs/1603.07333), in which we demonstrated a rapid algorithm for obtaining joint 3D estimates of sky location and luminosity distance from observations of binary neutron star mergers with Advanced LIGO and Virgo. We argued that combining the reconstructed volumes with positions and redshifts of possible host galaxies can provide large-aperture but small field of view instruments with a manageable list of targets to search for optical or infrared emission. In this Supplement, we document the new HEALPix-based file format for 3D localizations of gravitational-wave transients. We include Python sample code to show the reader how to perform simple manipulations of the 3D sky maps and extract ranked lists of likely host galaxies. Finally, we include mathematical details of the rapid volume reconstruction algorithm.Comment: For associated data release, see http://asd.gsfc.nasa.gov/Leo.Singer/going-the-distanc

    THERMODYNAMIC PROPERTIES AND PHASE RELATIONSHIPS IN THE U-C SYSTEM AND SELECTED U-M-C SYSTEMS

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    Results of phase and thermodynamic studies strongly suggest only small differences in stability for the different uranium carbides. Partial phase diagram studies are made on several U--M--C ternary systems. Studies of the U-- Zr-- C and the U--Nb--C system indicate improved physical properties and stability for (U,M)C solid solutions in some reactor fuel applications. A relatively large number of compounds of the type UMC/sub 2/ exist and may exhibit desirable properties as specific reactor fuels. For example, UMoC/sub 2/ does not hydrolyze and does not react with C to form UC/sub 2/. (auth

    The interaction between pesticides and particles in rivers. Final Report

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