2,639 research outputs found

    Cutaneous eccrine glands of the foot pads of the rock hyrax (Procavia capensis, Hyracoidea, mammalia)

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    In order to find correlations between skin gland morphology and specific ethological features, the cutaneous glands of the foot pads of Procavia capensis were studied by histological and various histochemical methods and by electron microscopy. In the foot pads, abundant specific eccrine skin glands occur, which consist of coiled tubular secretory portions and coiled ducts. The wall of the secretory part is composed of cuboidal glandular cells and myoepithelial cells. Among the glandular cells two types occur: clear and dark cells. Clear cells have numerous mitochondria and form a basal labyrinth, indicating fluid transport. Dark cells, which stain strongly with periodic acid-Schiff, contain a highly developed perinuclear Golgi apparatus, large amounts of rough endoplasmic reticulum and many secretory granules indicating production of glycoproteins. Cytokeratin (CK) 19 was found in secretory compartments and ducts, CK14 only in duct cells. Single cells of the secretory coils and ducts may be stained with antibodies against antimicrobial peptides. Some glandular cells contain proliferating cell nuclear antigen-positive nuclei especially in the ducts indicating an increased cell proliferation. Terminal transferase (TdT)-mediated d-UTP nick-end labeling-positive nuclei can be detected predominantly in the secretory coils and rarely in the transitional portions between ducts and end pieces. We suppose that proliferating cells migrate from the ducts to the secretory coils. The secretory product of the eccrine cutaneous glands seems to improve the traction between the foot pads of these animals and the steep and smooth rock formations among which they live

    Calibration of a general optical equation for remote sensing of suspended sediments in a moderately turbid estuary

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    Abstract A general algorithm for determining suspended sediment concentrations in the surface waters of estuaries has been developed for use with satellite data. The algorithm uses a three-parameter general optical equation to relate suspended sediment concentrations to water reflectances that have been corrected for sun angle effects, atmospheric path radiance, and tidal excursion. Using data collected by the advanced very high resolution radiometer on five different dates, reflectances were determined using two different methods, one providing maximum correction for haze and the other providing minimum sensitivity to pigments. For both methods, in situ and remotely sensed samples from Delaware Bay acquired within 3.5 hours of each other agreed to within 60% at the 95% confidence level. Pixel and subpixel scale spatial variations and variability associated with in situ measurements produced about 50% of the differences. Chlorophyll concentrations of \u3e50 μg/L produced a discrepancy in the reflectance method that provided the best haze correction. The parameter values may be adjusted to allow for variations in sediment size and pigment variations, allowing application of the calibration to estuaries having optically different suspended sediments

    Remote estimation of the diffuse attenuation coefficient in a moderately turbid estuary

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    Abstract Solutions of the radiative transfer equation are used to derive relationships of water reflectance to the diffuse attenuation coefficient (K) in moderately turbid water (K \u3e 0.5 m−1). Data sets collected from the NOAA AVHRR and in situ observations from five different dates confirm the appropriateness of these relationships, in particular the logistic equation. Values of K calculated from the reflectance data agree to within 60% of the observed values, although the reflectance derived using a more comprehensive aerosol correction is sensitive to chlorophyll concentrations greater than 50 μg L−1. Agreement between in situ and remote observations improves as the time interval between samples is narrowed

    Taxonomic status of Bambusaspis miliaris : B. robusta, and B. pseudomiliaris (Hemiptera: Coccoidea: Asterolecaniidae)

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    Based on an assessment of 50 morphological characters from 110 specimens of Bambusaspis miliaris (BoisduvalI869), B. robusta (Green 1908), andB. pseudomiliaris (Green 1922) from different geographic regions around the world, we conclude that these specimens represent the same species. Therefore, the taxa B. robusta and B. pseudomiliaris are considered junior subjective synonyms of B. miliaris

    Mixed Symmetry Solutions of Generalized Three-Particle Bargmann-Wigner Equations in the Strong-Coupling Limit

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    Starting from a nonlinear isospinor-spinor field equation, generalized three-particle Bargmann-Wigner equations are derived. In the strong-coupling limit, a special class of spin 1/2 bound-states are calculated. These solutions which are antisymmetric with respect to all indices, have mixed symmetries in isospin-superspin space and in spin orbit space. As a consequence of this mixed symmetry, we get three solution manifolds. In appendix \ref{b}, table 2, these solution manifolds are interpreted as the three generations of leptons and quarks. This interpretation will be justified in a forthcoming paper.Comment: 17 page

    Statistical analysis of network data and evolution on GPUs: High-performance statistical computing

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    Network analysis typically involves as set of repetitive tasks that are particularly amenable to poor-man's parallelization. This is therefore an ideal application are for GPU architectures, which help to alleviate the tedium inherent to statistically sound analysis of network data. Here we will illustrate the use of GPUs in a range of applications, which include percolation processes on networks, the evolution of protein-protein interaction networks, and the fusion of different types of biomedical and disease data in the context of molecular interaction networks. We will pay particular attention to the numerical performance of different routines that are frequently invoked in network analysis problems. We conclude with a review over recent developments in the generation of random numbers that address the specific requirements posed by GPUs and high-performance computing needs
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