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TB Mitchell JJ Bollinger DHE Dubin X Huang WM Itano RH Baughman 《Science (New York, N.Y.)》1998,282(5392):1290-1293
Laser-cooled 9Be+ ions confined in two-dimensionally extended lattice planes were directly observed, and the images were used to characterize the structural phases of the ions. Five different stable crystalline phases were observed, and the energetically favored structure could be sensitively tuned by changing the areal density of the confined ions. The experimental results are in good agreement with theoretical predictions for the planar (infinite in two dimensions) one-component plasma. Qualitatively similar structural phase transitions occur, or are predicted to occur, in other experimentally realizable planar systems. 相似文献
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Hamid ME Alla KM Ahmed SS El Shiekh AE Ibrahim KE 《Journal of the South African Veterinary Association》2006,77(2):90-91
We describe a rare case of a concurrent demodectic and sarcoptic mange in a 2-year-old heifer in Khartoum, Sudan. The lesions were massive lumps of granulomatous tumour-like dermatitis with thick, nodular folds mainly covering the head, neck and shoulders. Histopathological examination of the lesions revealed the presence of both Demodex bovis and Sarcoptes scabiei. The animal died regardless of the anti-parasitic treatment it received. 相似文献
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A K Elmubarak S A Kheir A I Abuelgasim 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1990,43(3):317-322
The first outbreak of reovirus infection in broiler chickens was observed in the Sudan in the largest poultry industry of the country. The disease was characterized clinically by growth retardation, lameness, poor feathering, shank depigmentation and occasionally retraction of the head. Grossly there was enlargement of the proventriculus, atrophy of the pancreas and bone abnormalities. Histopathologic changes included hepatitis, nephritis, myocarditis, pericarditis, catarrhal enteritis, pancreatic necrosis, encephalomalacia and ricketic changes. Details were described. Reovirus was isolated from affected birds and reisolated from experimentally infected chicks. Infection was confirmed by immunoelectrophoresis and agar gel precipitation tests. 相似文献
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ABSTRACT Despite the fact that nonemployment income makes up approximately one-third of all personal income, its impact on local area economies has not been closely examined. This study uses Michigan county data to examine the impact of nonemployment income on nonbasic income over a twenty-seven-year period. This impact is compared to the impact of basic income by employing regression analysis to estimate comparative multiplier effects for both types of income. Nonemployment income is found to have a significant impact on nonbasic income, particularly in metropolitan and nonmetropolitan urban counties, where its impact appears to be stronger than that of basic income. 相似文献
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