排序方式： 共有44条查询结果，搜索用时 156 毫秒
31.
生产上常通过测定葡萄果实的糖、酸质量分数确定采收时期,而葡萄果实的酚类物质与糖、酸合成并不完全同步,其质量分数在传统采收期并未达到最高。以2013年北京市延庆县张山营镇下营村2个地块的‘梅鹿辄’葡萄果实为试材,分析从正常采收至延迟采收期间浆果的果粒质量、体积、总酸质量分数、可溶性固形物°Brix值以及酚类物质(包括总酚、花色苷及黄酮醇)质量分数的变化。结果表明,葡萄果实单粒质量和体积以及总酸质量分数随采收期的推迟呈下降趋势,浆果果皮/浆果质量比以及可溶性固形物°Brix值则呈上升趋势。果实酚类物质质量分数随采收时间推迟均呈上升趋势,通过延迟采收显著提高2个地块葡萄果实的总酚、花色苷及黄酮醇质量分数。因此,在9月末至10月初降雨较多的年份,延庆地区‘梅鹿辄’葡萄可推迟至10月20日以后采收,通过延迟采收能够提高延庆地区‘梅鹿辄’葡萄果实品质。 相似文献
32.
以《南京市新型农村社会养老保险办法》为依据,介绍了南京市新型农村养老保险的基本制度,并运用扩展的线性支出系统模型,测算出农民的基本消费支出,同时根据保险精算原理测算出满足农民基本养老需求所要缴纳的保险费,进而估量出农民在不同年龄的参保能力。研究发现,南京市新农保制度并不能完全保障农民的基本养老需求,政府财政补贴在制度建立和完善方面仍起着重要作用。据此提出了提高基本缴费比例、增加缴费浮动性、改革基本养老金计发方法等建议。 相似文献
33.
提出一种基于车轮侧向力和纵向力传感器信息的车辆状态观测器.建立3自由度车辆动力学模型,并构建扩展卡尔曼滤波器,结合纵向加速度传感器和横摆角速度传感器的校正信息,实时估计车辆的纵向车速和质心侧偏角.在复杂附着条件下,该车辆状态观测器对车轮滑移和路面附着条件有很好的鲁棒性.通过veDYNA车辆动力学仿真软件,对该观测器进行了仿真验证.在分离附着系数路面条件下的仿真结果显示,传统的基于2自由度和非线性轮胎模型估计方法的纵向车速最大估计误差为25 km/h,质心侧偏角最大估计误差为3°,相同工况下,提出的基于车轮力传感器信息的全轮驱动车辆状态观测器对车辆的纵向车速和质心侧偏角估计结果具有更好的精确度,最大估计误差分别不超过0.6 km/h和0.2°,对车轮滑移和复杂路面附着条件具有更强的自适应能力. 相似文献
34.
旨在通过科学测定县域农村饮用水价格以保障农村饮水安全工程发挥可持续效能。选取宜昌市点军区22个农村饮水安全工程进行实测,建立了成本水价模型测算供水工程成本水价,确定了水价下限;通过扩展线性支出系统(ELES)模型进行了水价承载力分析,基于调研结果修正承载力系数以测算承载力水价,确定了水价上限。首次提出并运用以人均供水成本和人均收入作为水价分类方法,通过分类成本水价的测算和修正,最终得到宜昌市点军区农村饮水安全工程的分类指导水价。结果表明,在保证农村饮水安全工程可持续运行和当地居民可承受的前提下,该测算方法能为县域农村饮水安全工程制定科学合理的水价提供借鉴。 相似文献
35.
Extended‐Spectrum β‐lactam Resistance in the Enteric Flora of Patients at a Tertiary Care Medical Centre 
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下载免费PDF全文 T. F. Landers D. F. Mollenkopf R. L. Faubel A. Dent P. Pancholi J. B. Daniels T. E. Wittum 《Zoonoses and public health》2017,64(2):161-164
The dissemination of Enterobacteriaceae expressing resistance to extended‐spectrum cephalosporins, which are therapeutically used in both human and veterinary medicine, is of critical concern. The normal commensal flora of food animals may serve as an important reservoir for the zoonotic food‐borne transmission of Enterobacteriaceae harbouring β‐lactam resistance. We hypothesized that the predominant AmpC and ESBL genes reported in US livestock and fresh retail meat products, blaCMY‐2 and blaCTX‐M, would also be predominant in human enteric flora. We recovered enteric flora from a convenience sample of patients included in a large tertiary medical centre's Clostridium difficile surveillance programme to screen for and estimate the frequency of carriage of AmpC and ESBL resistance genes. In‐ and outpatient diarrhoeic submissions (n = 692) received for C. difficile testing at the medical centre's clinical diagnostic laboratory from July to December, 2013, were included. Aliquoted to a transport swab, each submission was inoculated to MacConkey broth with cefotaxime, incubated at 37°C and then inoculated to MacConkey agars supplemented with cefoxitin and cefepime to select for the AmpC and ESBL phenotypes, with blaCMY and blaCTX‐M genotypes confirmed by PCR and sequencing. From the 692 diarrhoeic submissions, our selective culture yielded 184 isolates (26.6%) with reduced susceptibility to cefotaxime. Of these, 46 (6.7%) samples harboured commensal isolates carrying the AmpC blaCMY. Another 21 (3.0%) samples produced isolates harbouring the ESBL blaCTX‐M: 19 carrying CTX‐M‐15 and 2 with CTX‐M‐27. Our results indicate that β‐lactam resistance genes likely acquired through zoonotic food‐borne transmission are present in the enteric flora of this hospital‐associated population at lower levels than reported in livestock and fresh food products. 相似文献
36.
Frank?M.?BakkerEmail author Rik?Feije André?J.?Grove Gijs?Hoogendoorn Gerrit?Jacobs Edwin?D.?Loose Pam?van?Stratum 《Journal of Soils and Sediments》2003,3(2):73-77
We provide a test protocol to evaluate the effects of plant protection products on mortality and reproductive performance
ofHypoaspis aculeifer (Acari: Laelapidae). The test design is in compliance with standard characteristics of extended laboratory studies as formulated
by international expert panels dealing with non-target arthropod testing schemes. Potential effects on survival rates are
evaluated by assessing mortality after an exposure period of 14 days that starts with protonymphs. The reproductive performance
of surviving mites is studied by following the egg production of individually isolated females over a 7-day period. The hatching
success of these eggs is assessed subsequently. Using several years’ data obtained from water control treatments, we propose
criteria to evaluate the validity of individual experiments. 相似文献
37.
基于扩展卡尔曼滤波的车辆质量与道路坡度估计 总被引：2，自引：0，他引：2
针对车辆自动变速器控制系统难以实时测得车辆质量与道路坡度参数这一问题,运用最优估计理论,以车辆纵向动力学模型为基础,建立系统的状态空间模型,运用前向欧拉法将过程方程离散化,进一步对非线性过程方程进行近似线性化,获得过程方程向量函数的Jacobian矩阵,实现了基于扩展卡尔曼滤波(EKF)的车辆质量及道路坡度估计算法。在Matlab/Simulink仿真平台下,进行了实车道路试验数据的离线仿真。仿真结果表明,该算法可有效估计车辆质量及道路坡度,能够满足车辆自动变速器控制系统的要求。 相似文献
38.
Stefan B?rjesson Bj?rn Bengtsson Cecilia Jernberg Stina Englund 《Acta veterinaria Scandinavica》2013,55(1):3
Background
The already high and increasing occurrence of extended-spectrum beta-lactamases (ESBL) producing Escherichia coli in European broiler populations is of concern due to the fact that third and fourth generation cephalosporins are deemed critically important in human medicine. In Sweden 34% of the broilers carry ESBL/pAmpC producing E. coli in their gut, despite the absence of a known selection pressure such as antimicrobial usages. The aim of the current study was to characterise a selection of E. coli strains carrying the blaCTX-M-1, to determine if the spread was due to a specific clone.Findings
Ten isolates carrying blaCTX-M-1 from Swedish broilers belonged to eight different multi-locus sequence types with three isolates belonging to ST155. The ST155 isolates were identical as assessed by PFGE. The blaCTX-M-1 was in all isolates carried on a plasmid of replicon type incI, which also transferred resistance to tetracycline and sulfamethoxazole.Conclusion
The occurrence of ESBL-producing E. coli in the Swedish broilers is not due to the emergence of a single clone, but rather the spread of a specific incI plasmid carrying blaCTX-M-1. 相似文献39.
24年田间定位试验研究表明,长期不施肥处理和化肥PK配施处理土壤表层N呈下降趋势,而施入化肥N处理(包括化肥N、化肥NP配施、化肥NK配施、化肥NPK配施处理)N增加较缓慢,有机与无机肥结合处理土壤表层N增加迅速。以长期不施肥为对照,长期有机肥 NPK处理水稻增产最多,达35.94%。随着N肥的逐年施入,土壤表层全N含量与产量间由显著正相关关系变为相关性不显著。 相似文献
40.
利用与甘蓝显性雄性不育基因（Ｍｓ）连锁的延长随机引物扩增ＤＮＡ（ＥＲＰＡＤ）标记ＥＰＴ１１９００对３３个甘蓝自交系的多态性进行了分析。ＥＰＴ１１９００主要分布在各种早熟甘蓝中,很少存在于鸡心类型或晚熟扁圆类型甘蓝中。该结果表明：它可用于辅助大多数鸡心型或晚熟扁圆类型甘蓝的Ｍｓ基因转育;ＥＰＴ１１９００在辅助两个甘蓝自交系回交三代及两个青花菜自交系回交一代的Ｍｓ基因转育中,预测的准确性超过９０％。 相似文献