205 research outputs found

    Utility of Landsat Image in the Study of Land Cover and Land Surface Temperature Change

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    AbstractScientists have aimed at exploring land use and land cover (LULC) and their environmental influence in order to improve our understanding of the causes and consequences of these phenomena. This study addresses and use and land cover change (LUCC) in the upper reaches of Pearl River Delta, China, from 1990 to 2008. Based on remotely sensed images of Landsat, LUCC and land surface temperature were assessed. Results showed that land surface temperature was highly influenced by the LUCC from 1990 to 2008. An examination of the relationship between the LULC and LST maps was finally conducted to comprehension their interactions. Results indicated that Landsat image was effective for quantifying the heat environment and providing reliable measurements of land use change. LST was found to be positively correlated with impervious surface but negatively correlated with vegetated land. Each temperature zone was associated with a dominant LULC category

    Ginzburg-Landau-type theory of non-polarized spin superconductivity

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    Since the concept of spin superconductor was proposed, all the related studies concentrate on spin-polarized case. Here, we generalize the study to spin-non-polarized case. The free energy of non-polarized spin superconductor is obtained, and the Ginzburg-Landau-type equations are derived by using the variational method. These Ginzburg-Landau-type equations can be reduced to the spin-polarized case when the spin direction is fixed. Moreover, the expressions of super linear and angular spin currents inside the superconductor are derived. We demonstrate that the electric field induced by super spin current is equal to the one induced by equivalent charge obtained from the second Ginzburg-Landau-type equation, which shows self-consistency of our theory. By applying these Ginzburg-Landau-type equations, the effect of electric field on the superconductor is also studied. These results will help us get a better understanding of the spin superconductor and the related topics such as Bose-Einstein condensate of magnons and spin superfluidity.Comment: 9 pages, 5 figure

    DETC2005-84370 STUDY ON THE SENSITIVITY OF CONTROLLABLE PARAMETERS IN AN ACTIVE VIBRATION ISOLATION SYSTEM OF AIR SPRING WITH RUBBER BELLOW

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    ABSTRACT The characteristics of control parameters of air spring with rubber bellow are analyzed through finite element method and thermodynamic equation respectively. The analysis results indicate that the vertical stiffness of air spring is sensitive to the varying of vertical displacement and volume, and nonlinearly varies with vertical displacement. When the air spring is pressed down or pulled up under the exterior excitation, the height of air spring can be controlled to keep stable through adjusting the volume of air spring by the use of hydraulic transformer

    Impulse-based reciprocal measurement of the transfer functions of underwater structure

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    An impulse-based reciprocal method is proposed for measuring the transfer functions of underwater structure. This method uses an impulse sound source, and the volume velocity of source is derived from the detected sound pressure. The influences of the reverberant sound field on the detected sound pressure are eliminated by an operation with time gates. Numerical simulation verifies that this impulses-based reciprocal measurement can obtain results with accuracy similar to the traditional reciprocal measurement method using electromagnetic source. Because much less time is required in the impulse-based measurement, the time efficiency is boosted. This method is also validated in a lake experiment, and the experimental result shows that the influences of the reverberant field on the derived volume velocity are eliminated

    Expression of DCX and Transcription Factor Profiling in Photothrombosis-Induced Focal Ischemia in Mice

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    Adult neurogenesis is present in the dentate gyrus and the subventricular zone in mammalian brain under physiological conditions. Recently, adult neurogenesis has also been reported in other brain regions after brain injury. In this study, we established a focal striatal ischemic model in adult mice via photothrombosis (PT) and investigated how focal ischemia elicits neurogenesis in the striatum. We found that astrocytes and microglia increased in early post-ischemic stage, followed by a 1-week late-onset of doublecortin (DCX) expression in the striatum. The number of DCX-positive neurons reached the peak level at day 7, but they were still observed at day 28 post-ischemia. Moreover, Rbp-J (a key effector of Notch signaling) deletion in astrocytes has been reported to promote the neuron regeneration after brain ischemia, and we provided the change of gene expression profile in the striatum of astrocyte-specific Rbp-J knockout (KO) mice glial fibrillary acidic protein (GFAP-CreER:Rbp-Jfl/fl), which may help to clarify detailed potential mechanisms for the post-ischemic neurogenesis in the striatum

    Progress in Research and Application of Insect-resistant Packaging for Grain Storage

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    Stored grain is extremely vulnerable to the storage insects during storage and processing. At present, chemical control is still the main method for controlling stored grain insects. However, the increasing resistance of insects caused by long-term use of chemical control raises unprecedented challenges. Insect-repellent packaging, as a traditional and emerging physical insect prevention method, has increasingly attracted widespread attention among people. The types and characteristics of food packaging materials, the types and application of insect-repellent packaging, the research and evaluating methods of insect-repellent packaging at home and abroad, and the problems existing in the practical application of insect-repellent packaging were reviewed, and the development trend of insect-repellent packaging was prospected, so as to provide reference information for the scientific and efficient use of insect-repellent packaging, development of new insect-repellent packaging to control stored grain insects in the future

    Cross-sectional study of the relationship of peripheral blood cell profiles with severity of infection by adenovirus type 55

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    BACKGROUND: The immunologic profiles of patients with human adenovirus serotype 55 (HAdV-55) infections were characterized in subjects diagnosed with silent infections (n = 30), minor infections (n = 27), severe infections (n = 34), and healthy controls (n = 30) during a recent outbreak among Chinese military trainees. METHODS: Blood was sampled at the disease peak and four weeks later, and samples were analyzed to measure changes in leukocyte and platelet profiles in patients with different severities of disease. Differential lymphocyte subsets and cytokine profiles were measured by flow cytometry and Luminex xMAP®, and serum antibodies were analyzed by ELISA and immunofluorescence staining. RESULTS: Patients with severe HAdV infections had higher proportions of neutrophils and reduced levels of lymphocytes (p < 0.005 for both). Patients with minor and severe infections had significantly lower platelet counts (p < 0.005 for both) than those with silent infections. The silent and minor infection groups had higher levels of dendritic cells than the severe infection group. Relative to patients with silent infections, patients with severe infections had significantly higher levels of IL-17(+)CD4(+) cells, decreased levels of IL-17(+)CD8(+) cells, and higher levels of IFN-γ, IL-4, IL-10, and IFN-α2 (p < 0.001 for all comparisons). CONCLUSIONS: Patients with different severities of disease due to HAdV-55 infection had significantly different immune responses. These data provide an initial step toward the identification of patients at risk for more severe disease and the development of treatments against HAdV-55 infection

    New Insights into Traffic Dynamics: A Weighted Probabilistic Cellular Automaton Model

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    From the macroscopic viewpoint for describing the acceleration behavior of drivers, this letter presents a weighted probabilistic cellular automaton model (the WP model, for short) by introducing a kind of random acceleration probabilistic distribution function. The fundamental diagrams, the spatio-temporal pattern are analyzed in detail. It is shown that the presented model leads to the results consistent with the empirical data rather well, nonlinear velocity-density relationship exists in lower density region, and a new kind of traffic phenomenon called neo-synchronized flow is resulted. Furthermore, we give the criterion for distinguishing the high-speed and low-speed neo-synchronized flows and clarify the mechanism of this kind of traffic phenomena. In addition, the result that the time evolution of distribution of headways is displayed as a normal distribution further validates the reasonability of the neo-synchronized flow. These findings suggest that the diversity and randomicity of drivers and vehicles has indeed remarkable effect on traffic dynamics.Comment: 12 pages, 5 figures, submitted to Europhysics Letter
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