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吉林省西部草原现状及草原"三化"已成为吉林西部地区环境恶化,制约社会、经济可持续发展的主要"瓶颈",这不仅给人们生产和生活带来了极大的危害,也直接威胁着吉林西部生态安全。通过分析草原生态环境恶化产生的原因,有针对性提出草原生态环境存在的主要问 相似文献
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张佳 《国外畜牧学(猪与禽)》2013,33(3):19-20
上周五(2月4日),美国农业部发布了巴西和阿根廷已开始收获的谷物估计产量。相比一年前,这两个国家的玉米和大豆供应量有所增加(表1)。如果美国农业部的预测准确,大豆的产量将同比增加3 0 0 0万t(1 2亿蒲式耳),玉米产量将同比增加3 3 0万t(2 2 5 0 0万蒲式耳)。良好的天气造就了较 相似文献
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用硫酸铵沉淀、离子交换层析和亲和层析等方法,从鸡的胰和十二指肠中提纯了胰淀粉酶(P-Amyl)和十二指肠淀粉酶(D-Amyl).提纯倍数分别为67.5倍和78.8倍.二者提取液等电聚焦电泳鉴定均出现1条酶带,等电点分别为4.5和4.6.聚丙烯酰胺梯度凝胶电泳测定,二者的分子量均为53500.以可溶性淀粉为底物,测得P-Amyl和D-Amyl的Km值分别为6.20×10~-5和1.16×10~-5mol/L.P-Amyl对热敏感,D-Amyl则较稳定.EDTA强烈地抑制P-Amyl的活性,而对D-Amyl的抑制作用弱.P-Amyl和D-Amyl的最适pH分别为7.0和6.6.对P-Amyl和D-Amyl,Ca~(2+)、Mg~(2+)和Co~(2+)均有不同程度的激活作用,Cu~(2+)和Mn~(2+)有抑制作用;Zn~(2+)对P-Amyl有抑制作用;低浓度Fe~(3+)对P-Amyl有激活作用,高浓度Fe~(2+)对P-Amyl和D-Amyl均有抑制作用. 相似文献
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Beran GW 《Preventive veterinary medicine》2008,86(3-4):198-207
When early people made their appearance, zoonotic infectious diseases were already waiting, but epidemic diseases did not appear in human history until people began to live in large numbers under conditions of close contact, mainly during the last 10,000 years. Disease has decimated urban populations, conquered armies, and disrupted society. The focus here is on (1) the plague of Athens and the Black Death; (2) smallpox, influenza, and rabies; (3) avian influenza prion diseases, and foot & mouth disease; and (4) emerging and re-emerging diseases. All have veterinary public health associations. In Athens, Greece, in 430 BC, when the Spartans ravaged the countryside, hordes crowded into Athens so that orderly movements, space in which to live, and adequate supplies of food became impossible. Crowding of any population fosters disease transmission; chaos and disorder enhance it all the more. Out of northern Egypt came a terrible plague from across the Mediterranean Sea. The identity of the plague of Athens remains unsure, but the well-considered conclusion is Rift Valley Fever, a mosquito borne, viral zoonosis. The Black Death, also called the Plague, raged in Asia for centuries. In 1347, the Black Death was brought by a ship out of Asia to Sicily. The scenes of devastation were repeated throughout Europe, with 90% or more of the people dying in city after city. Influenza, too, has been a cause of periodic human epidemics, but the great pandemic of influenza occurred in the last months of World War I. In the years of highest occurrence, more than half the world's population became clinically infected. If veterinary public health had been born earlier, it could have led to elucidating the epidemiology of influenza and the plagues of Athens, Europe, and Asia. In turn, smallpox had also caused continual tragedy. In 1796, Edward Jenner began to harvest pustules of cowpox from children or infected cows and inject them into susceptible children. In 1980, the World Health Organization declared that smallpox had been eliminated from the world. Rabies, though, still strikes terror. A number of animal diseases, broadly termed emerging and re-emerging diseases, need surveillance because they have the potential to impact human health. From late in 2003 to 2007, the highly pathogenic H5N1 influenza virus in poultry infected at least 121 people and caused 62 deaths in four countries. The prion diseases, too, all have very high numbers in concentrated contacts. To control these diseases, veterinary public health is essential, with diagnosis, epidemiological surveillance, clinical manifestations, and prevention as primary measures. 相似文献
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在动物的异常行为中以刻板行为最为常见,而咽气癖又是马最常见的口部刻板行为之一。作者就咽气癖在生理方面和心智方面对马体产生的影响、行为基础、诱因的研究进展及常见的防治措施进行综述。 相似文献
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Dekker A Dercksen D Snoep J van Wuyjckhuise L 《Tijdschrift voor diergeneeskunde》2007,132(18):695-701
On 26th of july 2007 a new case of bluetongue was notified in the Netherlands and on 2nd of august 2007 foot-and-mouth disease was diagnosed in Surrey, England, which raised the threat of having both infections simultaniously in one area. Bluetongue and foot-and-mouth disease have a different pathogenesis, but symptoms may resemble each other at a later stage of infection. The pathogenesis and possible clinical symptoms of both infections are discussed and illustrated with pictures. 相似文献
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近几年,世界饲用添加剂市场增长较快,预计今后将进一步增长,据世界粮农组织(FAO)首领会议的倡议,到2015年,将使世界营养不良的人口削减一半,其间,肉制品将会以每年2％的速度增长,特别是加快猪肉和禽肉增长。这将促进世界添加剂,尤其是蛋氨酸和赖氨酸需求量的增加。 相似文献
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