从世遗标准看广东客家乡村景观的文化遗产价值

在认知粤东北传统客家乡村景观遗产分布、构成及现状的基础上,运用世界遗产杰出普世价值的评估标准,分析归纳了它作为文化景观的遗产价值;主要体现在三个方面:1)两千年中原文化南迁历史的活体见证;2)客家传统文化及民俗风貌的独特展示;3)岭南山区人居环境营造的杰出范例。     

海南岛热带天然林可持续经营单位、标准和指标及采伐作业的研究

具有“地球之肺”之称的热带森林,长期以来,只用来采伐木材和开垦农田等,使得热带森林尤其是热带天然林面积不断减少,质量不断降低。根据联合国粮农组织《１９９１年生产年鉴》资料,从１９８０～１９９０年,热带地区森林减少９％。全球濒临灭绝的有花植物为１万种,...     

邓恩桉优树的选择标准

以1988、1991年种植在广西柳州、桂林两地的邓恩桉为选优林分对象,用5株优势木对比法进行选优,同时研究了优树的入选标准.通过对50株候选优树和250株5株优势木生长量数据、分枝与干形得分值的分析,确定了本次选优的标准为:胸径≥优势木平均胸径1.2倍(或树高≥优势木平均树高1.06倍)、单株材积≥优势木平均单株材积1.44倍、分枝与干形二者综合得分5分以上(含),符合该选优标准的候选优树有26株,入选率为52%.该选优标准适合所研究的林分及与研究林分情况相近的邓恩桉林分的选优.     

祁连山水源涵养林可持续经营标准与指标体系的建立

阐述了森林可持续经营标准与指标的研究动态，分析了建立祁连山水源涵养林可持续经营标准与指标体系的必要性，提出了祁连山水源涵养林可持续经营的7个标准，28个指标，其目的是探讨祁连山水源函养林合理经营的理论依据，最大限度地保护和恢复祁连山的天然林资源，并取得较大的生态，经济和社会效益。     

27个木槿品种的数量分类和主成分分析

通过观测27个木槿品种的17个数量和质量性状,探究了木槿品种分类的等级和标准,便于为木槿品种的选育与资源研究等提供参考依据。首先对17个性状指标进行R型聚类分析和主成分分析,根据分析结果再对27个木槿品种进行Q型聚类分析。R型聚类分析结果表明,各性状选取是合理的;主成分分析结果表明,17个性状可综合为6个主成分,其累计贡献率达88.096%。Q型聚类结果表明,27个木槿品种根据有无丹心、花型、丹心基部形状、花瓣指数、花径、叶形、丹心线与丹心的关系可被分为2大类、3大类或8大类。16个性状对木槿品种的划分贡献较大。综合而言,有无丹心、花型、花瓣指数、丹心线与丹心的关系是木槿品种分类的主要标准和依据。     

N—110系列缝隙式喷雾喷头的报废标准探讨

本文对国产N—110系列缝隙式喷雾喷头的报废标准进行了探讨,提出了报废标准。     

不同决策准则下的模糊最短路径算法设计

通过引入参变量函数,设计不同决策准则下的模糊最短路径算法。由该算法决策者可以求解出各自的最满意路径。同时,基于人机交互作用,决策者还可以求出其他决策准则下的最优路径,从而为决策者提供了更多的决策信息。最后通过实例说明算法的有效性。     

Performance and fitness traits versus phenotypic appearance in the African Ankole Longhorn cattle: A novel approach to identify selection criteria for indigenous breeds

Ankole cattle are well known for their massive white horns and red coat colour. These characteristics are attributed to centuries of cultural breeding practices. Two experiments with traditional cattle keepers were carried out at a governmental Ankole nucleus farm in south-western Uganda to identify phenotypic characteristics as well as production and fitness traits which are important indigenous selection criteria. Forty one body measurements each were taken from 15 bulls and 35 cows and phenotypic characteristics were described in detail. In the first experiment 12 groups of 6 to 8 cattle keepers were invited to rank several groups of 4–5 animals according to their preference for a breeding bull or cow based on phenotype alone. In the second experiment the ranking was based on phenotype and a hypothetical life history that was randomly assigned to each animal on each day of experiment. The history included milk yield (on own performance for cows and that of the dam for bulls), fertility of the animal and its sire as well as events of East Coast Fever. For analysis, Generalized Multinomial Logit Models were fitted. To compare different models the likelihood-based pseudo R square measure was used. The results indicate that, in the selection of cows, performance and fitness traits are emphasized by the cattle keepers while in the selection of bulls, the phenotypic appearance of the animal plays an important role. Individual fertility followed by milk performance are the main criteria for selecting cows, resistance to East Coast Fever was of highest importance in bulls. In both sexes a dark red coat colour was highly rated. The study indicates that the methodology of preference ranking combining phenotype and a hypothetical life history may provide insight into indigenous selection criteria of stock owners elsewhere.     

水泵进水池模型试验新方法研究

针对我国目前水泵进水池模型试验相似准则不明确，忽视观测水泵进口流态和吸水管内涡流强度等缺陷，提出了水泵进水池模型试验研究的新方法。开敞式水泵进水池模型试验按弗劳德数相似准则模拟。不带泵进行试验，模型比尺的选取应保证一定的进水池宽度、水深和吸水管直径，从而提高试验结果的可靠性。模型试验应重点检查进水池中是否出现有害的水面涡和水下涡，控制水泵进口时均流速波动范围和吸水管内涡流强度的大小。     

The use of ecological traits in extinction risk assessments: A case study on geometrid moths

Identifying ecological traits that make some species more vulnerable than others is vital for predictive conservation science. By identifying these predisposing traits we can predict which species are most prone to decline and gain an understanding of the reasons behind the decline. The aim of this study was to determine the ecological traits that best predict extinction risk and distribution change in Finnish geometrid moths and to develop an understanding of the biological connections between these traits and threats. We found that larval specificity, overwintering stage and flight period length predicted distribution change and extinction risk. There was also an interaction effect between larval specificity and body size on both distribution change and extinction risk. In monophagous species the host plant distribution predicted extinction risk. Even though ecological traits are known to be important determinants of extinction risk, the IUCN red list categorization system is exclusively based on quantitative measures of populations and ignores the ecological traits. Here, we propose that taxon specific ecological data should also be used to predict extinction risk at least on a regional scale to improve the accuracy of the IUCN extinction risk classification.