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1.
卡尔纳普主张从哲学中清除形而上学。他拒斥行而上学.对综合命题提出了确证代替证实的标准,后来走向概率研究,为现代归纳逻辑发展开辟了新方向;对于分析命题则从句法分析到语义分析,为语言哲学和分析哲学作出了贡献。然而他主张的物理主义却并未成为现实。  相似文献   
2.
Eight strains of Taylorella equigenitalis were identified by a polymerase chain reaction using a primer pair specific to the 16S rDNA of T equigenitalis. These eight strains were chosen because they had previously been shown to represent eight distinct genotypes by pulsed-field gel electrophoresis analysis after separate digestion of the genomic DNA with ApaI or NotI. The eight strains could be classified into six or seven types by random amplified polymorphic DNA analysis using different kinds of primers. Amplified rDNA restriction analysis after separate digestion with five restriction enzymes, including AluI and MboI, of the 1,500 bp fragments of rDNA amplified by polymerase chain reaction did not discriminate the genomic variations among the eight strains of T equigenitalis. Thus, pulsed-field gel electrophoresis was shown to discriminate these eight organisms better than random amplified polymorphic DNA analysis, while amplified rDNA restriction analysis was found to be unsuitable for subtyping T equigenitalis.  相似文献   
3.
应用前后对比分析法,对三峡水库重庆库区云阳县移土培肥一期与二期工程进行效益分析;得出移土培肥工程将给三峡库区带来巨大的生态效益、经济效益和社会效益的结论;说明该工程不仅能带动库区经济发展,并对其社会及生态环境产生深远影响。  相似文献   
4.
Amoebic gill disease (AGD) affects the marine culture phase of Atlantic salmon, Salmo salar L., in Tasmania. Here, we describe histopathological observations of AGD from smolts, sampled weekly, following transfer to estuarine/marine sites. AGD was initially detected histologically at week 13 post-transfer while gross signs were not observed for a further week post-transfer. Significant increases (P < 0.001) in the proportion of affected gill filaments occurred at weeks 18 and 19 post-transfer coinciding with the cessation of a halocline and increased water temperature at the cage sites. The progression of AGD histopathology, during the sampling period, was characterized by three phases. (1) Primary attachment/interaction associated with extremely localized host cellular alterations, juxtaposed to amoebae, including epithelial desquamation and oedema. (2) Innate immune response activation and initial focal hyperplasia of undifferentiated epithelial cells. (3) Finally, lesion expansion, squamation-stratification of epithelia at lesion surfaces and variable recruitment of mucous cells to these regions. A pattern of preferential colonization of amoebae at lesion margins was apparent during stage 3 of disease development. Together, these data suggest that AGD progression was linked to retraction of the estuarine halocline and increases in water temperature. The host response to gill infection with Neoparamoeba sp. is characterized by a focal fortification strategy concurrent with a migration of immunoregulatory cells to lesion-affected regions.  相似文献   
5.
Two trials were designed to quantify the effect of feeding ratio and fish size on the cohabitation transmission of Loma salmonae, the causative agent of microsporidial gill disease (MGD) in salmonids, Oncorhynchus spp. To evaluate the effect of feeding ratio on disease onset, groups of 45 rainbow trout, O. mykiss (Walbaum) (RBT), were fed daily at 1% (low), 2% (medium) or 4% (high) of the fish biomass in the tank. There were three tanks at each feeding level: two tanks were exposed to the pathogen and one was a control. For the second objective, 300 RBT were separated into seven tanks so that the weight classifications were small (17-23 g), medium (32-38 g) and large (57-63 g). Each size class was done in duplicate with one control tank containing medium-sized fish. Separately for each trial, on day 0 post-exposure (PE) five highly infectious RBT were added to each tank (not including the control tanks) to begin the cohabitation exposure period. Beginning on day 21 PE and continuing biweekly until days 70 and 77 PE for the feeding and fish size trials, respectively, each fish was evaluated for visible branchial xenomas to determine disease onset time. Using survival analysis, the survival curves for the low, medium and high feedings were not significantly different from each other. However, there were significant differences amongst the small, medium and large weight classes in the size trial. The median numbers of days to the development of branchial xenomas was 31, 38 and 42 for small, medium and large size fish, respectively. On any given day, a medium or large sized fish had a hazard ratio for developing branchial xenomas of 0.66 and 0.63, respectively, compared with a small fish. In addition to host species and host strain differences, fish size is now considered a host risk factor for the development of MGD.  相似文献   
6.
The genetic contribution of 51 broodstock, comprising 29 females and 22 males, reared at Hiroshima City Marine Products Promotion Center for the production of stocked black sea bream was monitored during two consecutive years using seven microsatellite DNA loci. The high discrimination ability of these markers was reflected in the polymorphic identification content (PIC=0.831), the exclusion probability (Q≈1), and the low probability of identity index (I=3.635−10). The total number of breeders contributing to the mating process was estimated at 32 (62.7%) in 2000 and 30 (58.8%) in 2001. On pedigree reconstruction, 69.3% of the offspring were successfully assigned to a single broodstock pair. Loss of alleles accounted for 16.9% during seed production; nevertheless, 90.9% of males and 69.0% of females participated in the mating process. Based on microsatellite genetic tagging, 58.9% of the fish sampled during the two months after release were identified as hatchery stock, presenting no significant differences from wild conspecifics in either fork length or body weight.  相似文献   
7.
我国的现代化建设必须要坚持走中国特色的新型工业化、信息化、城镇化、农业现代化(以下简称“四化”)同步发展的道路。文章阐述了“四化”同步发展的科学内涵,并对“四化”之间的相关系系做了论证,在对我国“四化”存在问题分析的基础上。提出了加快信息化进程,实现“四化”同步发展的对策措旋。  相似文献   
8.
采用大型通用有限元分析程序ABAQUS进行了方钢管混凝土轴压短柱力学性能模拟,分析了各个阶段构件的承载能力。结果表明:有限元计算的极限荷载和荷载-平均纵向应变曲线与试验结果符合较好,说明网格划分、边界条件、材料本构关系的选取基本正确,适用于钢管混凝土短柱的非线性分析。  相似文献   
9.
张佳佳  封皖 《安徽农业科学》2014,(30):10487-10488
简述了伟思富奇恒温恒湿箱以及与之配套使用的神荣露点仪日常维护与保养的注意事项,指出以预防故障为前提的日常维护工作的必要性.分析了设备可能出现的故障情况,并列举排除故障的方法和维修措施.  相似文献   
10.
多相混输泵输送技术在油田的应用   总被引:1,自引:0,他引:1  
多相混输泵输送技术是近几年发展较快的一项新技术,概述了混输泵应用的意义及试验情况,对混输泵试验的结果及设计安装中的有关问题进行了分析和讨论,,介绍了多相混输泵现场应用效果和经验。  相似文献   
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