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Data in the wavelength range 0.545-1.652 w m from the Moderate Resolution Imaging Spectroradiometer (MODIS), launched aboard the Earth Observing System (EOS) Terra in December 1999, are used to map daily global snow cover at 500 m resolution. However, during darkness, or when the satellite's view of the surface is obscured by cloud, snow cover cannot be mapped using MODIS data. We show that during these conditions, it is possible to supplement the MODIS product by mapping the snow cover using passive microwave data from the Special Sensor Microwave Imager (SSM/I), albeit with much poorer resolution. For a 7-day time period in March 1999, a prototype MODIS snow-cover product was compared with a prototype MODIS-SSM/I product for the same area in the mid-western USA. The combined MODIS-SSM/I product mapped 9% more snow cover than the MODIS-only product. 相似文献
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In pigs the lymphocytes emigrating from the intestinal wall were collected by cannulating the lymphatics, labeled in vitro using a fluorescent dye and retransfused. The injection of 6.6+/-4.2 x 10(8) cells resulted in a labeling index between 1.5% in intestinal lymph, 0.2% in the spleen and lymph nodes, approximately 0.1% in the intestinal lamina propria and 0.003% in intraepithelial lymphocytes. About 25 % of the injected cells were present in the blood and 1 % was recovered in the lymph. T cells were found in similar proportions in the injected and the recovered cells in the organs (70-80%). The proportion of IgA+ cells among the immigrated cells in the intestinal lamina propria ranged from 5 to 8%, which in absolute numbers was up to 60% of the injected IgA+ cells. T and IgM+ cells did not show a higher accumulation in any organ. These experiments in conventional, unrestrained animals revealed that (1) T cells immigrate into the intestinal lamina propria, (2) preferential migration of IgA+ cells from gut lymph to the intestinal lamina propria is obvious under in vivo conditions and (3) the immigrated IgA+ cells represent a very small population which is difficult to detect when analyzed in relative numbers. 相似文献
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A Schellart R Veldkamp M Klootwijk F Clemens S Tait R Ashley C Howes 《Water science and technology》2005,52(3):137-146
A greater understanding of the erosion behaviour of sewer sediments is necessary in order to reliably estimate the amount and nature of the sewer sediments released from deposits in sewers and transported either to waste water treatment plants or discharged into the environment. Research has indicated that microbial activity in sediment can influence the physical release of sediment from in-pipe deposits. This paper reports on a series of erosion tests in which sewer sediments from different sewer networks are kept under different environmental conditions and their resistance to erosion is examined. The erosion tests are carried out under aerobic and anaerobic conditions and two temperatures, one representing ambient sewer temperatures and a lower temperature that significantly suppresses bacterial activity. 相似文献
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RG Stock K Chan M Terk JK Dewyngaert NN Stone P Dottino 《Canadian Metallurgical Quarterly》1997,37(4):819-825
The authors review the literature on intra-adenomatous pituitary apoplexy with special emphasis on pathophysiology, diagnosis and therapeutic approach. They present five cases, from a series of 86 patients with pituitary tumors, that developed this syndrome. The patients were diagnosed and followed by the Neurosurgery and Endocrinology Services of Hospital Universitario Clementino Fraga Filho, Universidade Federal do Rio de Janeiro. Diagnosis was confirmed by CT-Scan and MRI in all cases, and the treatment of choice was surgical. Conclusions point to the diagnostic difficulties and the urgency of treatment in this clinical setting. 相似文献
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MZ Shakhmardanov VI Luchshev VM Bondarenko NN Isaeva 《Canadian Metallurgical Quarterly》1997,75(7):47-49
Flexner's dysentery is often accompanied with intestinal dysbacteriosis. Disbiotic changes in the intestine contribute to specific shigella endotoxins entering blood flow thus prolonging clinical symptoms of the underlying disease. Administration of bacterial biological preparations (bifidumbacterin forte, lactobacterin) relieves specific endotoxemia, reduces the duration of the disease and has an immunomodulating action. 相似文献
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A transport-field parallel-plate formulation and solution method to determine the small-signal propagation constant is given for wide microstrip lines over an inhomogeneously doped semiconductor substrate of small transverse dimensions. Included in the detailed transport model are two carrier species, recombination-generation mechanisms, DC and AC field-dependent mobilities and diffusion constants, and boundary condition contact effects. A transverse DC bias condition is applied. Structures numerically simulated are a voltage-variable GaAs distributed Schottky-barrier phase shifter and a transmission line over an Si bipolar junction. Numerical data based on a finite-difference technique are generated on carrier densities, electric potentials and fields, and current densities. Propagation constant calculations compared favorably to those calculated by both full-wave field analysis and moments-of-the-Boltzmann-equation analysis for some less general cases. Propagation constant results for the GaAs structure are compared with available experimental data, and good agreement is obtained 相似文献