欧盟共同农业政策面临的挑战及最新改革措施

共同农业政策作为联系欧盟成员国农业的纽带,在经历2003年的改革后,虽然在价格补贴、农村发展等方面取得一定的成效,但仍然面临财政负担、食品安全、新成员国加入等来自内外部的挑战和压力.为应对这些挑战和压力,欧盟进行了降低政策价格、微调配额等一系列的最新改革.     

农业信息：传统与现代的耦合

近年来，国家投资建设大量信息基础设施，以保证农业信息能更好的被农户采用。而现实中，农户并不通过网络、电视和报刊等现代信息手段获得农业信息，相反，基于地缘和血缘的熟人网络和以盈利为目的的商人成了农业信息传播的主要媒介。在这种传播方式下，农户的利益常遭侵害，农业科技难以广泛有效的传播，甚至一些假信息让农户失去了对“科技”的信赖。针对目前存在的种种问题，笔者兼顾现实与未来，提出了相关对策。     

沙门氏菌鞭毛蛋白属共同抗原表位的定位

用淋巴细胞杂交瘤技术研制成４株沙门氏菌属特异单抗ＣＢ８，ｄｅ７，ｃｃ６，ＤＤ４，在免疫转印试验中，证实它们所识别的抗原表位位于鞭毛蛋白上，ＥＬＩＳＡ相加试验及竞争试验显示，ＣＢ８和ｃｃ６与ｄｅ７，ＤＤ４识别的抗原表位不同，表明鞭毛蛋白的属共同抗原具有多种表位的特性。用胰蛋白酶消化鞭毛蛋白，ＳＤＳ－ＰＡＧＥ结果出现两条新带，分子量分别为４２０００（Ｆ４２），２７０００（Ｆ２７），长时间消化，最终只剩下Ｆ２７条带，它可抵制该酶的消化。对该酶切样品的免疫转印结果表明，沙门氏菌鞭毛蛋白属共同抗原表位出现于Ｆ４２和Ｆ２７上，而相应的沙门氏菌分型Ｈ抗原单抗或因子血清识别的表位也在Ｆ４２和Ｆ２７上都得到了证实。这为沙门氏菌鞭毛蛋白抗原的多样性及结构和功能研究提供了证据。     

Seroprevalence of porcine and human influenza A virus antibodies in pigs between 1986 and 1988 in Hassia

1,268 sera collected from slaughtered pigs in Hassia (FRG) from 1986 to 1988 were tested for antibodies against porcine and human influenza A virus strains using the single radial haemolysis test (SRHT). Antibodies against the porcine strains (subtype H1N1) A/Swine/Arnsberg/1/81, A/Swine/Iowa/15/30 and A/New Jersey/7/76 were detected in 411 (32.4%), 318 (25.1%) and 304 (24.0%) of sera, respectively. Up to 1988 a slight increase (10%) in the seroprevalence to A/Swine/Arnsberg/1/81 was noticed, whereas the results obtained with the other strains showed little variation. Antibodies against the human H1N1 strain A/Singapore/6/86 were only found in sera collected 1987 and 1988 in rates of 1.6% and 3.0%. Serological indication of infections with the human H3N2 strains A/Victoria/1/75, A/Hong Kong/1/68 and A/Philippines/2/82 could be shown in 286 (22.6%), 178 (14.4%) and 135 (10.6%) of the serum samples. Within the three year period the rate of sera positive for antibodies against A/Philippines/2/82 increased from 6.5% to 23.0%, whereas no variation in the rates were found using the other H3N2 strains. Antibodies simultaneously against porcine (H1N1) and human (H3N2) virus strains were detected in 9.9% of all sera tested.     

发展沙早事业 推进结构调整

开发利用水土资源，推进黄土山区经济结构调整，实现经济社会可持续发展，是值得研究的重要课题，结合柳林县的实际，从农田水利基本建设，水土保持生态建设，水资源统一管理，科技兴水，落实政策，更新机制等方面论述了如何发展水利事业，推进结构调整。     

2009年大豆市场行情回顾与2010年展望

2009年国际大豆市场触底反弹，美元疲软、流动性过剩是其上涨的外因。南美减产、中国需求增加是国际大豆回暖的关键因素．偏紧的供求结构让国际大豆库存面临考验。     

鸡新城疫免疫失败的原因及防制措施

1 免疫失败的原因1.1 免疫方式不当。鸡的新城疫(ND)保护性抗体可分为粘膜表面的IgA和血清中的IgG,只有呼吸道粘膜抗体和血清抗体都达到一定滴度时才能有效防止新城疫发生。由于免疫方法选择不当(如饮水免疫),致使鸡的呼吸道粘膜抗体未达到保护水平,或使血清中新城疫抗体不高,都可引起鸡发生新城疫。     

A formation mechanism for catalytically grown helix-shaped graphite nanotubes

The concept of a spatial-velocity hodograph is introduced to describe quantitatively the extrusion of a carbon tubule from a catalytic particle. The conditions under which a continuous tubular surface can be generated are discussed in terms of this hodograph, the shape of which determines the geometry of the initial nanotube. The model is consistent with all observed tubular shapes and explains why the formation process induces stresses that may lead to "spontaneous" plastic deformation of the tubule. This result is due to the violation of the continuity condition, that is, to the mismatch between the extrusion velocity by the catalytic particle, required to generate a continuous tubular surface, and the rate of carbon deposition.