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931.
随着现阶段城市建设速度的加快,各地因拆迁行为引发的争议越来越激烈。为了更好地协调城市发展与私人权益的关系,2011年1月21日国务院颁布了《国有土地上房屋征收与补偿条例》(简称《征收条例》,下同)。与先前的《城市房屋拆迁管理条例》相比较,《征收条例》无论在立法的价值目标、具体的实施机制方面都有很大的区别。以《征收条例》和相关立法作为制度框架,构建并逐步完善房屋征收与补偿过程中的维权机制,有助于使得包括《征收条例》在内的上述立法得以贯彻实现,从而使得利益博弈在市场经济、法治国家的轨道上进行。 相似文献
932.
张学全 《内蒙古林业调查设计》2013,36(3):96-99
古林箐自然保护区位于北回归线以南,哀牢山南端以东的滇东南高原向东南半岛延伸的结合部,南亚热带与热带的过渡地带。在这特殊的自然地理条件下,成为我国三大生物多样性中心之一的滇东南—桂西北的核心部位,区内有发育完整,保存完好的森林生态系统和丰富的生物资源。但在管理中存在许多方面问题,据此提出保护措施。 相似文献
933.
934.
超干种子老化方法比较研究 总被引:5,自引:3,他引:5
本试验种用谷子、绿豆,经40℃及45℃,湿度RH=95%-100%老化6天及5天。然后测各含水量的5项活力指标。经生物统计表明:谷子40℃,45℃二处理间差异显著,且40℃高温老化6天时间,在不同含水量的组合上,除含水量0.85%外,其余二因子组合均优于45℃老化6天的不同含水量处理,且有0.01显著差异。绿豆老化温度亦以40℃较好,种子含水量老化结合谷子和绿豆均以5.8%处理效果最好,二种作物经 相似文献
935.
本文根据变量理论分布对区试中b值及CV值参数的数量分类,提出了适于目前普及推广的查表计算法。在此基础上,对区试品种提出了按主要生产性能指标以量定性的评定分类体系。从而推出可排除主观随意性干扰、较为完整严密的区试汇总模式,并以范例作了运用说明。 相似文献
936.
二倍体栽培棉种草棉和亚洲棉的核型比较研究 总被引:5,自引:0,他引:5
以二倍体栽培棉种草棉(Gossypium herbaceumL.)3个品种和亚洲棉(G.arboreum L.)6个品种,以及1个亚洲棉与草棉种间杂种 F_1为材料,进行核型分析。结果表明,草棉和亚洲棉在核型上基本相似,其主要差异是草棉具有2对 st 染色体,而亚洲棉中没有;虽然2个棉种的核型类别都属于2A 型,但草棉的核型比亚洲棉更对称,属于较原始的类型。来 相似文献
937.
938.
Ignacy Misztal Ignacio Aguilar Daniela Lourenco Li Ma Juan Pedro Steibel Miguel Toro 《Journal of animal science》2021,99(6)
Genomic selection (GS) is now practiced successfully across many species. However, many questions remain, such as long-term effects, estimations of genomic parameters, robustness of genome-wide association study (GWAS) with small and large datasets, and stability of genomic predictions. This study summarizes presentations from the authors at the 2020 American Society of Animal Science (ASAS) symposium. The focus of many studies until now is on linkage disequilibrium between two loci. Ignoring higher-level equilibrium may lead to phantom dominance and epistasis. The Bulmer effect leads to a reduction of the additive variance; however, the selection for increased recombination rate can release anew genetic variance. With genomic information, estimates of genetic parameters may be biased by genomic preselection, but costs of estimation can increase drastically due to the dense form of the genomic information. To make the computation of estimates feasible, genotypes could be retained only for the most important animals, and methods of estimation should use algorithms that can recognize dense blocks in sparse matrices. GWASs using small genomic datasets frequently find many marker-trait associations, whereas studies using much bigger datasets find only a few. Most of the current tools use very simple models for GWAS, possibly causing artifacts. These models are adequate for large datasets where pseudo-phenotypes such as deregressed proofs indirectly account for important effects for traits of interest. Artifacts arising in GWAS with small datasets can be minimized by using data from all animals (whether genotyped or not), realistic models, and methods that account for population structure. Recent developments permit the computation of P-values from genomic best linear unbiased prediction (GBLUP), where models can be arbitrarily complex but restricted to genotyped animals only, and single-step GBLUP that also uses phenotypes from ungenotyped animals. Stability was an important part of nongenomic evaluations, where genetic predictions were stable in the absence of new data even with low prediction accuracies. Unfortunately, genomic evaluations for such animals change because all animals with genotypes are connected. A top-ranked animal can easily drop in the next evaluation, causing a crisis of confidence in genomic evaluations. While correlations between consecutive genomic evaluations are high, outliers can have differences as high as 1 SD. A solution to fluctuating genomic evaluations is to base selection decisions on groups of animals. Although many issues in GS have been solved, many new issues that require additional research continue to surface. 相似文献
939.
Chlamydia abortus is one of the most common abortive agents worldwide in sheep. Few studies have been reported C. abortus infection among sheep in Egypt but the available data is scarce. The objective of the present study was to determine the seroprevalence of C. abortus among sheep, the associated risk factors and its molecular characterization. The present study was conducted on 675 sheep in six Governorates at Northern Egypt. Data analysis confirmed the presence of antibodies against C. abortus in 93 out of 675 sheep. The logistic regression model was fitted to identify the associated risk factors with C. abortus infection. The results revealed that C. abortus increased significantly in ewes (OR = 4.04, 95 %CI: 1.44−11.28) during autumn season (OR = 3.6, 95 %CI: 1.64–8.28), in ewes with a history of abortion (OR = 1.4, 95 %CI: 0.87–2.50) and in farm where no lambing pen (OR = 2.2, 95 %CI: 1.30–3.94) or abscence of post abortion measures (OR = 1.96, 95%CI: 1.23-3.12). In addition, age, flock size and exchange of breeding ram had no significant effect on prevalence of chlamydiosis. Also, PCR assay was confirmed presence of C. abortus as accusative pathogen in aborted ewe and the genetic characterization of Egyptian C. abortus strain revealed 100 % identity with another strain from Iraq. A control program should be applied to reduce economic losses and risk of human infection. 相似文献
940.
为探索精子发生的分子机制,寻找精子变形期间的关键基因,本研究从公共基因表达数据库下载小鼠精细胞的转录组测序数据,利用R软件Ballgown程序包筛选差异表达基因,并对差异表达基因进行Gene ontology(GO)和Kyoto Encyclopedia of Genes and Genomes(KEGG)富集分析后,再对筛选出的关键基因进行分析。结果显示:筛选出8个相关性较强的关键通路,将其所包含的基因进行FPKM值从大到小排序,取前18名的基因进行功能分析。其中,Txnrd3和Tcp1与繁殖活动相关;Gpx4、Dkkl1、Dbil5与发育相关;Prm2、Selenof、Tnp1、Tnp2、Ropn1l、Pafah1b2、Spink2和Prm1等8个基因参与精子发生;Spa17、Ldhc、Hsp90aa1、Gstm5和Csnk2b参与鞭毛和纤毛的形成。以上基因对精子发生具有重要作用,深入发掘这些基因的功能特点可为进一步揭示精子变形机制提供理论依据。 相似文献