基于PEST分析的中国农业电子商务 竞争环境研究     

杜丹  路文如 《勤云标准版测试》2009,29(8)

农业电子商务是一种先进的商务模式,能改进中国农业市场流通环节存在的突出矛盾.中国农业电子商务还处在网上农业商务信息服务发展的初期.作者运用了竞争情报理论中的PEST分析工具,从政治、经济、社会以及技术四个方面分析了中国现阶段农业电子商务行业所处的宏观竞争环境.研究结果表明,中国目前的农业电子商务行业虽然在信用体系、农产品标准化等方面还存在很多不足,但基本的硬件条件已具备.制约农业电子商务发展的主要障碍是农民用户比较传统的意识形态.农业电子商务企业首先应充分认识到开展农业电子商务的必要性,然后以国家农业政策为依托,努力提高农业电子商务的认知度,帮助农民用户转变传统思维.  相似文献   

园林意境 生态校园——山东省花园式单位哈尔滨工业大学（威海）          下载免费PDF全文

{{each article.authors author i}} {{if author.authorNameCn && author.authorNameCn != ''}}{{@ author.authorNameCn}}{{if i != article.authors.length - }}  {{/if}} {{/if}} {{/each}} 《中国城市林业》2009,7(4):78-78

哈尔滨工业大学新校区坐落于胶东半岛海滨城市——威海,是有着87年发展历史的全国著名重点高校哈尔滨工业大学校区之一,创建于1987年,2002年学校正式更名为哈尔滨工业大学(威海)。校园依山傍海,环境幽雅,地理位置得天独厚,规划占地155hm2,其中绿地规划面积占62.29%,是一所正在蓬勃发展的花园式大学。    相似文献   

烟草赤星病拮抗细菌Ata28菌株的诱变选育     

chgxiao@swau.cq.c 《中国农学通报》2006,22(5):377-377

（西南大学植物保护学院,重庆 400716）  相似文献   

Failed attempt of Cryptosporidium andersoni infection in lambs     

Kvác M  Ditrich O  Kouba M  Sak B  Vitovec J  Kvetonová D 《Folia parasitologica》2004,51(4):373-374

Four lambs 4 months old were inoculated with Cryptosporidium andersoni oocysts (bovine isolate) in a dose of 5 x 10(6) per animal followed later by 1 x 10(7) oocysts per animal. No animal shed Cryptosporidium oocysts during 56 days post infection, no lamb showed clinical symptoms of cryptosporidiosis and no macroscopic changes were detected in the abomasum immediately after autopsy. Histological examinations did not demonstrate the occurrence of Cryptosporidium in the abomasum and other selected organs.  相似文献   

Study of immune response in pigs fed with high vitamin E-dosages     

Mudron P  Levkut M  Revajová V  Kovác G 《DTW. Deutsche tier?rztliche Wochenschrift》2000,107(10):411-414

The effects of long-term vitamin E-supplementation on phagocytic cells, lymphocyte sub-populations, and SWC3+ cell count were studied in pigs. Eighteen weaned pigs were divided into three groups: 1) 100 mg DL-alpha tocopheryl acetate/kg diet, 2) 200 mg DL-alpha tocopheryl acetate/kg diet, 3) control group (basic feed with 10 mg DL-alpha tocopheryl acetate/kg diet). The examination of the immune indices was performed on day 120 of feeding the supplemented diets. The higher dietary levels of vitamin E resulted in increased serum concentration of alpha-tocopherol for both experimental groups (p < 0.05) and there were no significant differences in counts of CD2+, CD4+, CD8+, B lymphocytes nor SWC3+ cells among the groups. Similarly, vitamin E supplementation did not affect the functions of phagocytic cells tested.  相似文献   

The urinary excretion of selenium in sheep treated with a vasopressin analogue     

Leng L  Boldizárová K  Faix S  Kovác G 《Veterinary research》2000,31(5):499-505

The renal excretion of selenium was investigated in ewes with an excretion of hypotonic urine (control group) and in ewes with a formation of highly concentrated urine. Chronic stimulation of the urinary concentrating activity of sheep kidneys was induced by a long-term treatment with 1-desamino-8-D-arginine vasopressin (dDAVP), a synthetic analogue of vasopressin with prolonged effects. Young animals with 22 to 25 kg b.w. were fed a normal protein diet providing a daily intake of 129.25 g of crude protein, 12.03 MJ of digestible energy and 0.18 mg of selenium for 3 weeks. The vasopressin treated sheep (n = 11) were given subcutaneous injections of 12.5 micrograms of dDAVP in glycerol twice daily for one week before the clearance measurement of renal functions. The control group (n = 11) was treated with glycerol only. The administration of dDAVP resulted in a highly significant decrease of the urinary flow rate (from 3.19 +/- 0.50 in control group to 0.33 +/- 0.03 mL.min-1 in dDAVP animals, P < 0.001) without changes in the glomerular filtration rate (80.18 +/- 6.36 in controls vs. 77.86 +/- 6.26 mL.min-1, NS). No effects on plasma selenium level were observed (0.17 +/- 0.03 in controls vs. 0.20 +/- 0.03 mumol.L-1, NS) but the amounts of selenium excreted were found to be highly significantly reduced (from 0.29 +/- 0.05 in controls to 0.03 +/- 0.01 nmol.min-1, P < 0.001) in dDAVP treated sheep. Despite a large reduction in urinary flow rate, the selenium concentration in urine was actually the same in both groups (0.09 +/- 0.01 mumol.L-1) resulting in a sharp fall in the renal clearance of selenium (2.20 +/- 0.54 in controls vs. 0.18 +/- 0.03 mL.min-1, P < 0.01) due to dDAVP. This seems to be a consequence of the large increase in the selenium solvent drag induced by a vasopressin treatment. The results presented suggest that vasopressin may contribute to maintenance of the selenium balance in sheep via its effects on renal function.  相似文献   

侧耳菌原生质体融合子的子实体发育及遗传重组     

Too.Y.b Kim.G.h 《安徽农业大学学报》1999,26(3):321-329

通过原生质体融合技术得到侧耳菌亲和与非亲和菌种的融合产物,亲和菌种间体细胞杂交得到异核体,而非亲和菌种杂交得到保留有双亲基因的结合体（核）。结合核子实体发育受光照、温度、营养及培养基的物理状态等因素影响。结合体不能形成初始融合菌落,但大多数成熟的子实体中存在锁状联合,与异核体相比,结合体具生长速率缓慢,有丝分裂阶段形成锁状联合及子实体发育不同步等特点。体细胞杂交后代可以分离到四种遗传型菌落：原养型、一种亲本营养缺陷型、另一亲本营养缺陷型及重组子营养缺陷型。一些结合体具备异常等位基因,说明在受体细胞染色体重排中有大片段随机整合位点。  相似文献   

入孵种蛋贮存以4天为宜     

山东枣强马雪云侯宗良等将新鲜种蛋和存放 《畜禽业》2000,(12):23

山东枣强马雪云、侯宗良等将新鲜种蛋和存放18℃、75％4d、8d和12d的种蛋同时入孵。在入孵的第2h、24h、48h和66h分别抽取4组存放不同天数的种蛋、测量蛋重丢失、蛋清PH值和蛋清厚度。结果表明：新鲜蛋清PH值在入孵后先迅速增加,至PH值为9时,变化缓慢,但最终表现新鲜蛋清PH值最低;入孵2h,新鲜蛋蛋清最厚,与贮存4d、8d和12d的种蛋比较,新鲜蛋的蛋清厚度在入孵后的前24h降低较快,贮存种蛋的蛋清厚度也逐渐下降,但下降缓慢,且贮存4d的蛋清厚度始终高于贮存8d、12d的种蛋;随着贮存和孵化时间的延长,种蛋重量丢失增加,直至趋向一致,即种蛋从种鸡产出至孵化结束,其蛋重丢失占种蛋重的百分比是一致的。新鲜蛋入孵24h的蛋清变化相当于种蛋在18℃,相对湿度75％环境下存放4d的变化,将新鲜蛋入孵,胚胎供养不足,死淘汰和弱雏率增大。而入孵前贮放4d的种蛋,其蛋清粘度和PH值变化刚好满足胚胎供养需要,孵化效果最佳。  相似文献   

常见耐药基因多重PCR方法的建立及用于禽致病性大肠杆菌耐药性监测     

张耀东  朱红  AFAYIBO Doss&#  h Jean Ap&#  tre  王瑶  易正飞  信素华  陶程琳  李涛  祁晶晶  田明星  丁铲  于圣青  王少辉 《畜牧兽医学报》2020,51(12):3193-3198

本研究旨在建立β-内酰胺类、四环素类、氨基苷类、酰胺醇类、磺胺类抗菌药物耐药基因的多重PCR检测方法,用于耐药基因的快速检测。根据GenBank公布的上述5类抗菌药物的耐药基因序列,设计17对特异性引物。通过优化PCR体系和反应程序,建立4组耐药基因（cat+floR+tetB+tetC;dfrA12+sul2+sul1+bla_CTX-M+bal_TEM-1;aac3+aph3+aadA1+strB;tetA+cmlA+strA+sul3）的多重PCR反应体系。然后,检测多重PCR方法的特异性和敏感性。利用建立的多重PCR方法检测42株禽致病性大肠杆菌的耐药基因,同时,检测其耐药性,比较分析耐药基因和耐药表型之间的相关性。结果显示,建立的4组多重PCR体系可有效扩增出17个耐药基因片段,测序结果表明特异性较好。敏感性结果表明,4组多重PCR体系的菌液敏感性分别为10³、10⁴、10⁴和10⁵CFU。禽致病性大肠杆菌分离株的耐药基因多重PCR和单重PCR检测结果一致,其携带的耐药基因和耐药表型的符合率为92.86%。本研究建立的耐药基因多重PCR方法能简便、快速地检测常见的耐药基因,可用于耐药基因的传播、流行调查。  相似文献   

双组分系统CpxR影响禽致病性大肠杆菌的耐药性、抗血清杀菌能力及毒力     

易正飞  张耀东  王瑶  朱红  陶程琳  AFAYIBO Doss&#  h Jean Ap&#  tre  李涛  祁晶晶  田明星  丁铲  于圣青  王少辉 《畜牧兽医学报》2021,52(4):1053-1060

CpxR是细菌中Cpx双组分系统（two component system,TCS）的反应调控蛋白,通过调控靶基因的转录表达,在细菌细胞膜稳定及毒力方面发挥作用。本研究旨在探究TCS CpxR对禽致病性大肠杆菌（avian pathogenic Escherichia coli,APEC）基本生物学特性、抗血清杀菌能力及致病性的影响。利用Red同源重组系统及互补质粒构建cpxR基因缺失株、互补株,然后比较分析野生株、基因缺失株与互补株的生长曲线、运动性、生物被膜形成能力、药物敏感性、抗血清杀菌能力、动物致病性的差异。结果显示：cpxR基因缺失株与野生株、互补株的生长速度和运动性能无明显差异,且缺失cpxR基因不影响APEC的生物被膜形成能力。然而,缺失CpxR导致APEC对阿米卡星和卡那霉素耐药性降低。血清杀菌试验结果显示,CpxR有助于APEC的抗血清杀菌能力。动物感染试验结果显示,野生株、cpxR基因缺失株和互补株对雏鸭的半数致死量（LD₅₀）分别为7.50×10⁵、7.50×10⁶、1.33×10⁶ CFU,表明CpxR缺失显著降低APEC的毒力。综上表明,TCS CpxR在APEC耐药性、抗血清杀菌能力及毒力方面发挥作用,为阐明APEC的环境适应性、生存能力及致病机制提供参考。  相似文献