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41.
Hans-Rolf Gregorius 《Ecological modelling》2012,224(1):1-10
Particularly in ecological and evolutionary genetics, methods of discerning complex traits are improving at a considerable rate. As a consequence, the resolution of intrinsically qualitative traits such as species affiliation or genetic type is increasing to degrees that blur their distinction from continuously varying characteristics. The common notion of diversity, however, relies on distinct features such as the states of qualitative traits, and it aims to assess variation as a counting of these features or types. This situation brings up the question of whether and how the diversity perspective of variation can be broadened to cover higher levels of complexity without sacrificing its concept. The present paper suggests two approaches that refer to established criteria for measures of diversity and that complement each other. The partitions approach treats complexity through general measures of difference between trait states, and the relations approach rests on general binary relations that capture structural aspects of diversity. Both approaches are shown to consistently imply effective numbers of types even in cases where distinct types are not explicitly specified. Practically all of the common methods of measuring diversity can be classified into either of the two approaches, and new opportunities for analyses of the diversity of complex traits are provided. The latter analyses include those of diversity in subdivided collections. Other perspectives of variation (such as dispersion, variances, etc.) are discussed and analyzed for their distinction from the diversity perspective. In many cases, the distinction can be made apparent with the help of diversity portraits. 相似文献
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环境监测的主要目的是为了保证人类能够居住在一个健康的生态环境之中,并可以使他们能够合理安全地使用自然资源,所以我们要通过多项措施,建立起完整的质量保证体系、完善和实践实验室认可制度、提高内部检测人员的素质,使他们自觉的适应环境管理的各项要求等,来提高环境监测的最终质量。 相似文献
44.
Socioeconomic indicators and the survival of the tropical rainforest of cross river state of Nigeria
An internal household survey of socioeconomic indicators in the Cross River State forest communities showed that basic infrastructural
facilities such as clean water supply, adequate waste disposal system, good roads and electricity are grossly inadequate.
There is a total absence of modern family planning practices in the communities, and population is projected to increase by
44.8% between 2000 and 2015 and 85.4% between 2000 and 2025. The study revealed that about 65% of the population of the rainforest
communities consists of subsistence farmers and power chain operators, and besides the 19% of the Cross River State Tropical
High Forestry (THF) already reported to have been lost to agriculture and plantation between 1972 and 1991, about 9% was lost
between 1991 and 2000. An additional 25% of the THF will be lost by 2025, leaving only 470600 hectares (4706 km2). With 84.1% of community members having an annual income less than $300, the survival potential of the Cross River State
rainforest in the next fifty years is very low, unless an effective forest management programme is encouraged by government
in partnership with all stakeholders. 相似文献
45.
This article describes some laboratory tests performed on each kind of sludge located in an industrial wastes landfill. Measured physical properties are: field capacity, hydraulic permeability, saturation water content, effective porosity and particle-size distribution. The laboratory apparatus is described; the obtained results are analyzed to point out the possible correlations among the examined parameters. The aim of this work is to provide a data bank for industrial wastes landfills useful to perform some applications such as the evaluation of the produced leachate quantity for landfills whose wastes are similar to the ones here considered. 相似文献
46.
Frank?E.?Rheindt Jürgen?GadauEmail author Christoph-Peter?Strehl Bert?H?lldobler 《Behavioral ecology and sociobiology》2004,56(5):472-481
High effective multiple queen mating is a rare but taxonomically widespread phenomenon in eusocial Hymenoptera that has arisen convergently in several taxa. In ants, high effective mating frequencies have been confirmed in only two clades: the higher leaf-cutters (Atta, Acromyrmex) and the
Pogonomyrmex seed harvesters. We analysed polyandry in
Pogonomyrmex badius, which has a life-history unique within the genus, and report the highest numerical mating frequencies thus far recorded in ants. We also show that P. badius is characterized by one of the highest effective mating frequencies hitherto found in ants. It is now clear that all major sub-clades of
Pogonomyrmex sensu stricto exhibit high levels of polyandry. Therefore, multiple mating must have arisen early in the evolution of the genus, and may have constituted a mechanism to increase offspring variability for queens that were confronted with increasingly complex levels of organization. Too few congeners have been investigated by the same method to be certain that polyandry in P. badius is really higher than in the rest of the genus. If so, research should concentrate on a possible link between high queen mating frequency and the distinct caste system found in P. badius.Communicated by L. Keller 相似文献
47.
EM有效微生物技术在我国的应用研究进展 总被引:18,自引:0,他引:18
EM有效微生物技术自问世以来已经在世界各国的养殖、环保、种植等领域广泛应用,本文详细介绍了EM生物技术在我国环境保护、种植业、养殖业等方面的应用。 相似文献
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