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81.
We examined variability in hierarchical beta diversity across ecosystems, geographical gradients, and organism groups using multivariate spatial mixed modeling analysis of two independent data sets. The larger data set comprised reported ratios of regional species richness (RSR) to local species richness (LSR) and the second data set consisted of RSR:LSR ratios derived from nested species-area relationships. There was a negative, albeit relatively weak, relationship between beta diversity and latitude. We found only relatively subtle differences in beta diversity among the realms, yet beta diversity was lower in marine systems than in terrestrial or freshwater realms. Beta diversity varied significantly among organisms' major characteristics such as body mass, trophic position, and dispersal type in the larger data set. Organisms that disperse via seeds had highest beta diversity, and passively dispersed organisms showed the lowest beta diversity. Furthermore, autotrophs had lower beta diversity than organisms higher up the food web; omnivores and carnivores had consistently higher beta diversity. This is evidence that beta diversity is simultaneously controlled by extrinsic factors related to geography and environment, and by intrinsic factors related to organism characteristics. 相似文献
82.
An optimised sequential extraction scheme for the evaluation of vanadium mobility in soils 总被引:1,自引:0,他引:1
Reviewing the current state of knowledge about sequential extraction applied for soil vanadium(V) fractionation, we identified an urgent requirement of an sequential extraction(SE) specified for V. Namely, almost all previous SE extracted only 8.4%–48% of total V in soils(excluding residue). Thus, we proposed an eight-step SE for V fractionation in soils according to the knowledge gained from literature and our own dissolution experiments with model minerals. After extracting the mobilisable and adsorbed V with de-ionised water and 5 mmol/L phosphate, 1 mol/L pyrophosphate was applied to gather organic matter bound V which minimised the artefact dissolving Al and Fe(hydr)oxides occurred when using HNO_3–H_2O_2for extraction. Extraction with 0.4 mol/L NH_2OH·HCl was highly selective toward manganese oxides. Fractionation of different crystalline Al and Fe(hydr)oxides associated V with 1 mol/L HCl, 0.2 mol/L oxalate buffer and 4 mol/L HCl at 95°C especially improved the extractability of V incorporated with crystalline phase associated V. The suitability of our new SE scheme was confirmed by its higher selectivity against the target phases and higher extraction efficiencies(55%–77% of total V) with model minerals and 6 soils of different properties than previous SE. 相似文献
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85.
Cell and molecular biological investigations have greatly contributed to our understanding of receptor and effector mechanisms in sensory, neuronal, and endocrine cells. A fascinating aspect of this line of research is how such mechanisms have evolved and how they interact with each other. As shown in this contribution, the vertebrate pineal organ is an interesting model to study these problems, because it undergoes a conspicuous transformation during phylogeny, comprises two well-chraracterized receptor mechanisms (photoreception and adrenoreception), and acts upon its targets via neuronal and neuroendocrine signals.
Herrn Professor Dr. Drs. h. c. A. Oksche zum 65. Geburtstag gewidnet 相似文献
Herrn Professor Dr. Drs. h. c. A. Oksche zum 65. Geburtstag gewidnet 相似文献
86.
Raphael Scheffler Christopher NeillAlex V. Krusche Helmut Elsenbeer 《Agriculture, ecosystems & environment》2011,144(1):281-289
Clearing for large-scale soy production and the displacement of cattle-breeding by soybeans are major features of land-use change in the lowland Amazon that can alter hydrologic properties of soils and the runoff generation over large areas. We measured infiltrability and saturated hydraulic conductivity (Ksat) under natural forest, pasture, and soybeans on Oxisols in a region of rapid soybean expansion in Mato Grosso, Brazil. The forest-pasture conversion reduced infiltrability from 1258 to 100 mm/h and Ksat at all depths. The pasture-soy conversion increased infiltrability from 100 to 469 mm/h (attributed to shallow disking), did not affect Ksat at 12.5 cm, but decreased Ksat at 30 cm from 122 to 80 mm/h, suggesting that soybean cultivation enhances subsoil compaction. Permeability decreased markedly with depth under forest, did not change under pasture, and averaged out at one fourth the forest value under soybeans with a similar pattern of anisotropy. Comparisons of permeability with rainfall intensities indicated that land-use change did not alter the predominantly vertical water movement within the soil. We conclude that this landscape is well buffered against land-use changes regarding near-surface hydrology, even though short-lived ponding and perched water tables may occur locally during high-intensity rainfall on pastures and under soybeans. 相似文献
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88.
Haiyan Zhang Keishiro Hara Helmut Yabar Yohei Yamaguchi Michinori Uwasu Tohru Morioka 《Sustainability Science》2009,4(2):263-279
To decouple economic growth from environmental degradation, the Chinese government proposed the circular economy (CE) strategy
as part of its 11th 5-Year Plan. This strategy expands the application of CE from individual enterprises to eco-industrial
parks (EIPs) and to the cities, provinces, and regions. We carried out field studies in three EIPs in Baotou, Suzhou, and
Shanghai. In this paper, we discuss the current state of CE and the sustainable development of EIPs in China. We first provide
detailed information on the three EIPs' infrastructures, preferential policies, CE frameworks, and eco-chains. We then examine
the status of sustainable development in the three EIPs from the perspectives of socio-economic, resource and material efficiency,
and environmental performance. The results indicate that the overall performance of the three EIPs is reasonably good with
respect to socio-economics, resources and materials, and efficiency and environmental protection, whereas green management
is rather weak and thus requires further improvement. We found that the CE frameworks along with eco-chains within the EIPs
are effectively improving resource and material efficiency. Moreover, we demonstrate that there are positive associations
among socio-economic, resource and material, and environmental indicators. Given the large presence of EIPs in the local economies,
these results suggest that EIPs play a key role in promoting sustainable development in China. 相似文献
89.
H Segner M Wenger AM Möller B Köllner A Casanova-Nakayama 《Environmental science and pollution research international》2011,19(7):2465-2476
Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present - on the example of teleost fishes - a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens. 相似文献
90.