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1.
杨泽新  蔡维湘 《草业科学》1995,12(2):17-21,24
通过对放牧山羊的牧草适口性,嗜食性和采食率及其相互关系的分析,表明山羊放牧对灌丛草地的植物适口性、嗜食性比率和采食率均以灌木嫩枝叶,中禾草和苔草属植物较优。季节性规律为:春季山羊喜哺食灌木嫩枝叶,灌木嗜食性比率较高,采食率也较高,夏季山羊喜草本植物,草本植物的嗜食性比率高于灌木,秋季山羊较喜啃食灌木枝叶,嗜食性比率灌木高于草本植物,采食率低于春季,灌木采食率高于草本植物。  相似文献   
2.
为了提高煤与瓦斯突出预测的准确性、保障采掘工作面的安全、高效推进和降低防突工程成本,根据“三率”(预测突出率、突出预测准确率、不突出预测准确率)各自具有的合理区间属性和权重,以张集煤矿采掘工作面为例,采用区间数关联决策方法,得出综合预测指标 F ′的最优化区间为[370,380];根据加权灰靶决策方法,得出预测指标临界值排序为400、390、380等;取最优化区间和排序靠前的临界值的交集,得到煤与瓦斯突出综合预测指标 F ′的临界值为380,并开展现场应用。结果表明,考虑评价指标的区间属性,并取预测指标区间与排序靠前的临界值的交集作为煤与瓦斯突出预测综合指标 F ′的最优临界值方法是合理的。  相似文献   
3.
A methodology for ranking and classifying performance of irrigation systems through multidimensional performance indicators is developed using fuzzy set theory. The procedure uses the concepts of fuzzy resemblance and fuzzy dominance. Preference levels reflecting management priorities are incorporated into the analysis using appropriate weighting factors. The application of the procedure is demonstrated through two case studies: the Shi-Jin irrigation district in Hebei Province, China and the Goulburn irrigation region in Victoria, Australia. The classification of performance periods for the Australian system shows three clusters indicating the predominant effect of the increase in waterlogged area when higher priority is given to this indicator. No clear trend appeared when equal weight was assigned to all indicators. The effect of economic reforms implemented in 1977–78 in China is clearly reflected in the resulting ranking and clustering of the performance periods in the Shi-Jin irrigation district. Performance levels following reforms are shown to be consistently higher.Units mu unit of area equal to 1/15 ha (666 m2) - jin unit of weight equal to 0.5 kg.  相似文献   
4.
以国内40所高校在英国职业与教育资讯机构QS亚洲大学排行榜及国内三大排行榜中的位序及位序波动分析为基础,运用SPSS统计分析软件对QS亚洲大学排行榜与国内三大排行榜进行相关性分析,结果表明,尽管国内外四大排行榜的指标体系不尽相同,但QS亚洲大学排行榜与国内三大排行榜之间存在显著的正相关关系,而国内三大排行榜之间也存在极为显著的正相关关系。多元化的评价指标体系更能反映高等教育多元化的现实,要客观地反映一所大学的综合实力必须进行多维评价结果比较。  相似文献   
5.
During the period 2000–03, local potato cultivars in Estonia, Latvia, Lithuania, Poland and Denmark were tested for foliar resistance to Phytophthora infestans (late blight) in an international field trial network. Four standard cultivars were included in the trials: Sava, Oleva, Danva and Kuras. Primary disease-assessment data were entered into a common database, and parameters from the disease progress curves were calculated and made available on interactive web pages. A regression model, using relative area under disease progress curve (RAUDPC) values for cv. Oleva as a reference, was developed for the estimation of 1–9 scale values, where 1 = most susceptible. Standard deviations for the estimated 1–9 scale values and a nonparametric rank stability analysis of RAUDPC were used to evaluate the stability of resistance of the cultivars. Overall, the results showed stability of resistance for cvs Sava, Oleva and Danva, but not for Kuras. Use of the Internet-based Web-Blight service in this study facilitated comparison of results among countries for the level and stability of resistance. The estimated 1–9 scale values were similar to, or slightly lower than, those from official cultivar lists or from the European Cultivated Potato Database, especially for the more resistant cultivars. Possible reasons for discrepancies from different sources and locations are discussed. It is concluded that RAUPDC and the derived 1–9 scale values are useful for ranking cultivars for resistance to P. infestans , but this information is not detailed enough for use in a decision support system for late blight control.  相似文献   
6.
森林旅游资源的分级   总被引:1,自引:0,他引:1  
为正确反映森林旅游资源系统的本质和客观差异,将森林旅游资源分为4个层次、6个项目、26个要素.以200分为总分,按各要素的权重系数分配各要素的赋分值,所得总高分高于171分为一级;161~170分为二级,以此类推,低于90分为十级,共分为10级.最后对9个森林旅游区的森林旅游资源进行了评价与分级.  相似文献   
7.
《Southern Forests》2013,75(2):85-92
A performance comparison of seven-year-old individuals of 13 Casuarina species/provenances in terms of survival, growth (diameter, height and volume), wood basic density and wood biomass was undertaken at Kongowe, Kibaha, Tanzania. The trial was laid out using a randomised complete block design with four replications. The results showed significant differences (P < 0.0001) in all parameters. Casuarina equisetifolia from Montazah National Park, Egypt, had the lowest untransformed survival (48.8%), whereas C. equisetifolia from Wagait Tower (North Timor), Indonesia, had the highest survival (87.5%). Casuarina equisetifolia from Montazah National Park, Egypt, had the lowest mean diameter (8.6 cm) while the C. junghuhniana provenance from Timor, Indonesia (seedlot no. 19489) had the highest diameter (14.8 cm). Casuarina equisetifolia from Montazah National Park, Egypt, had the lowest mean height (16.2 m), volume (22.1 m3 ha?1) and biomass production (23.5 t ha?1), whereas C. equisetifolia from Hadsamira Songkhla, Thailand, had the highest mean height (24.3 m), volume (66.4 m3 ha?1) and biomass production (72.9 t ha?1). In terms of wood basic density, the C. junghuhniana provenance from Timor, Indonesia (seedlot no. 19489) had the lowest (617 kg m?3), whereas C. equisetifolia from Wagait Tower (North Timor), Indonesia, had the highest (731 kg m?3). Ordinal ranking for the best-performing species/provenances revealed that the best two provenances were C. equisetifolia from Hadsamira Sonkhla, Thailand, and C. junghuhniana from Timor, Indonesia (seedlot no. 19491). The two poorest-performing provenances were C. equisetifolia from Montazah National Park, Egypt, and C. equisetifolia from Cotonou, Benin. The outstanding species/provenances are recommended for pilot planting at Kibaha and similar sites.  相似文献   
8.
Yield and adaptation of hexaploid spring triticale   总被引:2,自引:0,他引:2  
Summary Gains in yield and stability were analysed using grain yield data from the 8th to the 14th International Triticale Yield Nursery (ITYN) and differences in adaptation between complete and substituted triticales (X Triticosecale Wittmack) were examined. A trend of improving yield and adaptation was observed. As highly significant genotype × site interaction each year was not adequately described using regression analysis, yield stability was examined by ranking genotypes within sites and summarizing scores for individual genotypes across sites. Cluster analysis was used to study the relationships among sites and among genotypes. There was little evidence of sites grouping on a geographical basis. Grouping of genotypes showed a tendency for complete and substituted triticales to perform differently, suggesting that diversity for adaptation is maximized by utilizing both types in breeding.Progress for grain yield is compared with more spectacular gains in test weight and reasons for the different rates of improvement are postulated.Abbreviations CIMMYT International Maize & Wheat Improvement Centre - ITYN International Triticale Yield Nursery contribution from CIMMYT/Agriculture Canada (No. R-002)  相似文献   
9.
In the paper, the advanced assessment method of DEA (Date Envelopment Analysis) had been used to evaluate relative efficiency and select the optimal scheme of agricultural industrial structure adjustment. According to the results of DEA models, we analyzed scale benefits of every optional schemes, probed deeply the ultimate reason for not DEA efficient, which clarified the method and approach to improve these optional schemes. Finally, a new method had been proposed to rank and select the optimal scheme. The research is significant to direct the practice of the adjustment of agricultural industrial structure.  相似文献   
10.
本文归纳分析了澳大利亚国内大学的整体概况、国内八所名牌大学、国内各大学排名、高等教育十大领域以及在各大学中的分布、和悉尼大学的某些学科专业情况。  相似文献   
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