7,069 research outputs found

    LANDSAT Digital Data Base Preparation for the Pennsylvania Defoliation Application Pilot Test

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    A LANDSAT digital mosaic data base for the State of Pennsylvania was prepared for use in the development of an automated system to annually estimate the extent and severity of Gypsy Moth defoliation of hardward forests. The techniques for detecting the defoliation and development of a geographic information system (GIS) to assess damage is being developed jointly by NASA/Goddard Space Flight Center and Pennsylvania State University using the JPL prepared mosaic base. The JPL processing involved the use of ground control points from the Master Data Processor for planimetric control, resampling of the LANDSAT data to 57 x 57 meter pixels, realignment to north, and reprojection to the Universal Transverse Mercator (UTM) projection in UTM zones 17 and 18. The completed mosaic for each UTM zone was subdivided into 1 degree of latitude by 2 degrees of longitude quadrangles for easy data handling. Consideration is given to the issues of mapping standards, sensor and spacecraft platform characteristics, and their implication to geographic information systems operation. Methods for obtaining measures of accuracy for LANDSAT mosaics are reviewed

    Unveiling the nature of bright z ~ 7 galaxies with the Hubble Space Telescope

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    We present new Hubble Space Telescope/Wide Field Camera 3 imaging of 25 extremely luminous (-23.2 < M_ UV < -21.2) Lyman-break galaxies (LBGs) at z ~ 7. The sample was initially selected from 1.65 deg^2 of ground-based imaging in the UltraVISTA/COSMOS and UDS/SXDS fields, and includes the extreme Lyman-alpha emitters, `Himiko' and `CR7'. A deconfusion analysis of the deep Spitzer photometry available suggests that these galaxies exhibit strong rest-frame optical nebular emission lines (EW_0(H_beta + [OIII]) > 600A). We find that irregular, multiple-component morphologies suggestive of clumpy or merging systems are common (f_multi > 0.4) in bright z ~ 7 galaxies, and ubiquitous at the very bright end (M_UV < -22.5). The galaxies have half-light radii in the range r_1/2 ~ 0.5-3 kpc. The size measurements provide the first determination of the size-luminosity relation at z ~ 7 that extends to M_UV ~ -23. We find the relation to be steep with r_1/2 ~ L^1/2. Excluding clumpy, multi-component galaxies however, we find a shallower relation that implies an increased star-formation rate surface density in bright LBGs. Using the new, independent, HST/WFC3 data we confirm that the rest-frame UV luminosity function at z ~ 7 favours a power-law decline at the bright-end, compared to an exponential Schechter function drop-off. Finally, these results have important implications for the Euclid mission, which we predict will detect > 1000 similarly bright galaxies at z ~ 7. Our new HST imaging suggests that the vast majority of these galaxies will be spatially resolved by Euclid, mitigating concerns over dwarf star contamination.Comment: 26 pages, 11 figures and 5 tables. Updated to match MNRAS accepted versio

    Approximated maximum likelihood estimation in multifractal random walks

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    We present an approximated maximum likelihood method for the multifractal random walk processes of [E. Bacry et al., Phys. Rev. E 64, 026103 (2001)]. The likelihood is computed using a Laplace approximation and a truncation in the dependency structure for the latent volatility. The procedure is implemented as a package in the R computer language. Its performance is tested on synthetic data and compared to an inference approach based on the generalized method of moments. The method is applied to estimate parameters for various financial stock indices.Comment: 8 pages, 3 figures, 2 table

    An exploration into the client at the heart of therapy : a qualitative perspective

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    Over 50 years ago Eysenck challenged the existing base of research into psychotherapy. Since that time, a large number of investigations have been conducted to verify the efficacy of therapy. Recently however, an increasing number of studies have cast new doubts on this research base. Instead of therapy being a function of the therapist, it is now becoming ever more apparent that the client plays a prime role in the therapeutic process. The qualitative studies presented in this paper provide some examples of research that demonstrates that clients are actively involved in their therapy, even making counselling work despite their counsellor. These studies suggest that clients may not experience therapy as beneficially as traditional outcome studies indicate. This raises a new challenge to researchers to more fully explore the client's experience of therapy, a challenge to which qualitative methods of inquiry would appear well suited

    Carboplatin/taxane-induced gastrointestinal toxicity: a pharmacogenomics study on the SCOTROC1 trial

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    Carboplatin/taxane combination is first-line therapy for ovarian cancer. However, patients can encounter treatment delays, impaired quality of life, even death because of chemotherapy-induced gastrointestinal (GI) toxicity. A candidate gene study was conducted to assess potential association of genetic variants with GI toxicity in 808 patients who received carboplatin/taxane in the Scottish Randomized Trial in Ovarian Cancer 1 (SCOTROC1). Patients were randomized into discovery and validation cohorts consisting of 404 patients each. Clinical covariates and genetic variants associated with grade III/IV GI toxicity in discovery cohort were evaluated in replication cohort. Chemotherapy-induced GI toxicity was significantly associated with seven single-nucleotide polymorphisms in the ATP7B, GSR, VEGFA and SCN10A genes. Patients with risk genotypes were at 1.53 to 18.01 higher odds to develop carboplatin/taxane-induced GI toxicity (P&#60;0.01). Variants in the VEGF gene were marginally associated with survival time. Our data provide potential targets for modulation/inhibition of GI toxicity in ovarian cancer patients
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