1,294 research outputs found

    Classification of hyperspectral imagery with neural networks: comparison to conventional tools

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    Efficient exploitation of hyperspectral imagery is of great importance in remote sensing. Artificial intelligence approaches have been receiving favorable reviews for classification of hyperspectral data because the complexity of such data challenges the limitations of many conventional methods. Artificial neural networks (ANNs) were shown to outperform traditional classifiers in many situations. However, studies that use the full spectral dimensionality of hyperspectral images to classify a large number of surface covers are scarce if non-existent. We advocate the need for methods that can handle the full dimensionality and a large number of classes to retain the discovery potential and the ability to discriminate classes with subtle spectral differences. We demonstrate that such a method exists in the family of ANNs. We compare the maximum likelihood, Mahalonobis distance, minimum distance, spectral angle mapper, and a hybrid ANN classifier for real hyperspectral AVIRIS data, using the full spectral resolution to map 23 cover types and using a small training set. Rigorous evaluation of the classification accuracies shows that the ANN outperforms the other methods and achieves ?90% accuracy on test data

    Grain sorghum, 1978

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    Corn, 1978

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    Architectural Features of Streetscapes and Aging in Cameron County, Texas: Preliminary Results

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    The impact of architectural features in urban settings reveals priorities for its residents and the integration of social and natural environments. It has been estimated that 23% of global deaths to the environments in which people live. We aim to characterize the most prevalent architectural features of Cameron County, Texas streetscapes and analyze their role in health promotion and healthy aging

    The impact of premorbid adjustment, neurocognition, and depression on social and role functioning in patients in an early psychosis treatment program

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    Objective: Functional impairments are debilitating concomitants of psychotic disorders and are present early in the illness course and, commonly, prior to psychosis onset. The factors affecting social and role functioning in early psychosis (EP) following treatment are unclear. We evaluated whether six months of participation in the PREPR, Boston, EP treatment program, part of a public-academic community mental health center, was related to improvements in social and role functioning and whether premorbid adjustment in adolescence, baseline neurocognition, and depression symptoms predicted functional improvement. Method: The Global Functioning Social and Role scales, MATRICS neurocognitive battery, and Calgary Depression Scale were assessed at baseline and six months during naturalistic treatment, while premorbid adjustment was measured at baseline. All participants were psychotic disorder patients in PREPR (n = 46 with social functioning and 47 with role functioning measures at both time points). Results: Large improvements were observed in role functioning (d = 0.84) and medium to large improvements were observed in social functioning (d = 0.70). Models consisting of adolescent premorbid adjustment and change in depression symptoms predicted social and role functioning change, whereas neuropsychological functioning did not. Conclusions: Substantial improvements in social and role functioning were observed among this sample participating in a recovery-based EP program. The impact of clinical factors on social and role functioning was highlighted. Further studies of premorbid adjustment in adolescence and the treatment of depression in EP programs in controlled treatment trials are needed to confirm these findings

    Order by disorder and spiral spin liquid in frustrated diamond lattice antiferromagnets

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    Frustration refers to competition between different interactions that cannot be simultaneously satisfied, a familiar feature in many magnetic solids. Strong frustration results in highly degenerate ground states, and a large suppression of ordering by fluctuations. Key challenges in frustrated magnetism are characterizing the fluctuating spin-liquid regime and determining the mechanism of eventual order at lower temperature. Here, we study a model of a diamond lattice antiferromagnet appropriate for numerous spinel materials. With sufficiently strong frustration a massive ground state degeneracy develops amongst spirals whose propagation wavevectors reside on a continuous two-dimensional ``spiral surface'' in momentum space. We argue that an important ordering mechanism is entropic splitting of the degenerate ground states, an elusive phenomena called order-by-disorder. A broad ``spiral spin-liquid'' regime emerges at higher temperatures, where the underlying spiral surface can be directly revealed via spin correlations. We discuss the agreement between these predictions and the well characterized spinel MnSc2S4

    Canine NAPEPLD-associated models of human myelin disorders

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    Canine leukoencephalomyelopathy (LEMP) is a juvenile-onset neurodegenerative disorder of the CNS white matter currently described in Rottweiler and Leonberger dogs. Genome-wide association study (GWAS) allowed us to map LEMP in a Leonberger cohort to dog chromosome 18. Subsequent whole genome re-sequencing of a Leonberger case enabled the identification of a single private homozygous non-synonymous missense variant located in the highly conserved metallo-beta-lactamase domain of the N-acyl phosphatidylethanolamine phospholipase D (NAPEPLD) gene, encoding an enzyme of the endocannabinoid system. We then sequenced this gene in LEMP-affected Rottweilers and identified a different frameshift variant, which is predicted to replace the C-terminal metallo-beta-lactamase domain of the wild type protein. Haplotype analysis of SNP array genotypes revealed that the frameshift variant was present in diverse haplotypes in Rottweilers, and also in Great Danes, indicating an old origin of this second NAPEPLD variant. The identification of different NAPEPLD variants in dog breeds affected by leukoencephalopathies with heterogeneous pathological features, implicates the NAPEPLD enzyme as important in myelin homeostasis, and suggests a novel candidate gene for myelination disorders in people

    Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2

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    We have searched for the proton decay mode proton to neutrino K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0. We found one candidate event consistent with background, yielding a limit, tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters
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