Velikovskianism     

Greenberg LM 《Science (New York, N.Y.)》1978,200(4348):1336

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Effect of pre‐milking teat disinfection on clinical mastitis incidence in a dairy herd in Northern Queensland,Australia          下载免费PDF全文

SM Rowe  WP Tranter  RA Laven 《Australian veterinary journal》2018,96(3):69-75

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A comparison of the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts after calving in cows also given internal teat sealants     

LK Whitfield  RA Laven 《New Zealand veterinary journal》2018,66(1):44-47

AIM: To compare, in cows treated with an internal teat sealant, the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts (SCC) after calving.

METHODS: Cows from a spring-calving, pasture-based dairy farm in the Manawatu-Whanganui region of New Zealand were randomly allocated to receive either a short-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=291) or a long-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=288) at the end of lactation. Cows were managed on-farm with routine husbandry procedures through the dry period and following calving. A multivariable logistic regression model was used to determine the association between length of action of dry-cow therapy and the proportion of cows with a SCC >150,000?cells/mL at the first herd test after calving.

RESULTS: Age of cow, mean SCC for the preceding season and interval from calving to the first post-calving herd test were all associated with the proportion of cows with an individual SCC >150,000?cells/mL at the first herd test (p<0.001) Treatment with the short-acting dry-cow therapy was not associated with decreased odds of cows having a SCC >150,000?cells/mL at the first herd test compared with treatment with long-acting dry-cow therapy (OR=0.724; 95% CI=0.40–1.30).

CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, which routinely used internal teat sealants, the use of short-acting cloxacillin-based dry-cow therapy did not result in an increased proportion of cows with elevated SSC post-calving. This was a single farm, single year study but indicates that in this herd, changing from a long-acting to a short-acting antimicrobial may have no impact on the prevalence of subclinical mastitis.  相似文献   

植物促生菌及其促生机理 (续)   总被引：10，自引：0，他引：10  

黄晓东  季尚宁  Bernard Glick  Bruce Greenberg  卢林纲 《现代化农业》2002,(7):13-15

3 植物促生菌的促生长机理 3.1 产生嗜铁素 铁是生命的基本物质.不论是动、植物还是微生物,均需含铁蛋白来参与呼吸等一系列生理活动.尽管地球表面矿物含铁丰富,但土壤中能够直接为植物和微生物利用的铁却不多.土壤中铁主要以三价铁(Fe3+)状态存在,在pH值为7.4时其溶解度为10-18mol/L,此浓度下的铁一般无法满足土壤微生物繁衍和植物生长发育的需要.然而,某些细菌和植物分泌一种专门结合铁的小分子蛋白(siderophores)可从土壤中收集铁,这种物质被称之为嗜铁素.铁一旦与嗜铁素相结合则形成可溶性铁-嗜铁素复合体,并可通过植物和微生物细胞膜的特殊通道进入生物体内.氧化铁在体内还原后被释放并参与生物代谢活动.产生嗜铁素被认为是植物促生菌最主要的直接和间接促进植物生长的有效途径之一.植物促生菌产生的嗜铁素一般都具有高度的铁亲合性和专一性,含有各种能鳌合铁的结构基团(如邻二苯酚结构、羧基结构和乙二胺结构等)来摄取土壤中的铁,这种嗜铁素具有极强的吸收铁的能力,可在铁有效性极低时收集土壤中微量的移动性铁,从而使土壤中可用的铁降低至更为缺乏的程度.  相似文献   

Soviets, west discuss "think tank"     

Greenberg DS 《Science (New York, N.Y.)》1969,166(3911):1382

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Social science: federal agencies agree to end covert support     

Greenberg DS 《Science (New York, N.Y.)》1968,159(3810):64-66

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Dartmouth. Medical School shows good recovery from 1966 blowup     

D S Greenberg 《Science (New York, N.Y.)》1968,159(812):284-286

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Nanterre: a year later at campus where French student revolt began     

Greenberg DS 《Science (New York, N.Y.)》1969,164(3885):1261-1264

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ONR: Economy Cuts Hit London Office     

Greenberg DS 《Science (New York, N.Y.)》1968,161(3844):871-872

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The National Academy of Sciences: profile of an institution. I     

D S Greenberg 《Science (New York, N.Y.)》1967,156(772):222-229

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