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《Ecological modelling》2003,170(1):45-53
The effect of an environmental gradient on inter-specific plant competitive interactions is modeled in a simple empirical model with biologically interpretable parameters. The model allows testing of hypotheses on the effect of the gradient on plant competitive interactions, as well as making ecological predictions from simple competition experiments using standard statistical procedures. The model, which is general and can be applied to different abiotic and biotic environmental gradients, is applied to a specific case of two competing Arabidopsis thaliana genotypes along a gradient of the general fungal pathogen Peronospora parasitica. One of the A. thaliana genotype is susceptible to the fungal pathogen P. parasitica and the other genotype is resistant. The Bayesian posterior distribution of the probability that the resistant genotype outcompetes the susceptible genotype is calculated as a function of the pathogen level. The design of the studied A. thaliana competition experiments is the minimum required experimental design needed to apply the model. 相似文献
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Considering the significant roles of the policies in developing environmental finance, an overview is conducted on the environmental finance policies (EFPs) in China. This paper analyzed the definition, scope, evolution and main instruments of EFPs. The implementation progress of financial activities on each instrument are investigated respectively. Then the experiences learned from and failures discovered in the development of the EFPs are discussed well recommendations for further improvement of the EFPs and their implementation are provided. Our study found that the EFPs have been established in China after a four-phase evolution since the early 1980s. The policies have played a critical role in leading to a rapid development in environmental finance by involving more financial instruments to accomplish the objective-led environmental plans. Driven by the policies, the new green credit (GC), green security (GS), and green insurance (GI) instruments have been phased in as supplements to the conventional command and control approaches to improve the environmental governance of financial activities and pollution sources. However, the market mechanism of financial institution is limited due to their defensive and incapable performance on implementation some of EFP instruments. To further strengthen the effectiveness of EFPs in facilitating environmental man- agement, recommendations are made mainly on the aspects including developing more specific policy guidelines, enhancing information sharing and disclosure, providing sufficient economic incentives, establishing environmental liabilities with financial activities, and involving issues related to climate change, and biodiversity and ecosystem service. 相似文献
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城市化趋势下城郊土地利用结构变化的区位分析--以杭州市为例 总被引:3,自引:0,他引:3
以杭州市区为研究区,利用近卜年的土地利用系列统计资料和遥感解译数据,采用统计分析和区位原理,经过数值计算,分析了杭州市区扩建过程中土地利用动态变化特点,重点讨论了耕地和农作物播种面积的时空动态过程。通过区位商数和分离指数的计算分析,揭示了未来土地利用方式的时空变化趋势。研究结果表明,居民工矿用地和耕地面积的变化最为明显;农作物播种面积的递减速率高于耕地面积的递减速率;蔬菜播种面积的区域不平衡性最大,集中程度高。萧山区是未来主要的菜篮子工程发展区。 相似文献
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有机肥与化肥的生产能耗、投入成本和环境效益比较分析——以污泥堆肥生产有机肥为例 总被引:3,自引:0,他引:3
针对目前国内肥料生产和施用现状,分别从能耗、成本和污染物排放等三个方面对有机肥和化肥进行比较分析。化肥生产呈现高能耗和高污染排放,而有机肥则表现为低能耗、无污染的特点,同时还可消纳废弃物,减轻污染负荷。从投入成本上分析,化肥相对于有机肥具有一定优势,其单位面积和折纯养分投入分别是有机肥的53%和26%。有机肥相对于化肥,其污染物排放负荷很低。从节能减排和降低投入的角度,提出支持基于废弃物资源化的有机肥产业化发展。 相似文献
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Four control theory models of natural and environmental resource use, drawn from the existing literature, are developed in a manner to emphasize their technical and decentralized interpretive similarity. Renewable, nonrenewable, and amenity resource use are treated as closely related problems of optimal (biological, earth material, ecological, or environmental) capital allocation over time. Thus nonrenewable resources, and the problem of exhaustion, are just limiting (zero growth) cases of renewable resources, and the problem of species extinction. Just as exhaustion can be optimal, extinction can be optimal. Waste recycling is treated as part of the problem of optimal regeneration of “sclean” environmental capital; wilderness use as a problem of managing the regeneration of ecological capital. 相似文献
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C. Radhakrishna Rao 《Environmental and Ecological Statistics》1994,1(1):7-19
Statistical methods as developed and used in decision making and scientific research are of recent origin. The logical foundations of statistics are still under discussion and some care is needed in applying the existing methodology and interpreting results. Some pitfalls in statistical data analysis are discussed and the importance of cross examination of data (or exploratory data analysis) before using specific statistical techniques are emphasized. Comments are made on the treatment of outliers, choice of stochastic models, use of multivariate techniques and the choice of software (expert systems) in statistical analysis. The need for developing new methodology with particular relevance to environmental research and policy is stressed.Dr Rao is Eberly Professor of Statistics and Director of the Penn State Center for Multivariate Analysis. He has received PhD and ScD degrees from Cambridge University, and has been awarded numerous honorary doctorates from universities around the world. He is a Fellow of Royal Society, UK; Fellow of Indian National Science Academy; Foreign Honorary Member of American Academy of Arts and Science; Life Fellow of King's College, Cambridge; and Founder Fellow of the Third World Academy of Sciences. He is Honorary Fellow and President of International Statistical Institute, Biometric Society and elected Fellow of the Institute of Mathematical Statistics. He has made outstanding contributions to virtually all important topics of theoretical and applied statistics, and many results bear his name. He has been Editor of Sankhya and theJournal of Multivariate Analysis, and serves on international advisory boards of several professional journals, includingEnvironmetrics and theJournal of Environmental Statistics. This paper is based on the keynote address to the Seventh Annual Conference on Statistics of the United States Environmental Protection Agency. 相似文献
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Graeme Reed Nicolas D. Brunet Sheri Longboat David C. Natcher 《Conservation biology》2021,35(1):179-189
Over the past 3 decades, indigenous guardian programs (also known as indigenous rangers or watchmen) have emerged as an institution for indigenous governments to engage in collaborative environmental governance. Using a systematic review of peer-reviewed literature for research conducted in Australia, Canada, Aotearoa-New Zealand, and the United States, we sought to characterize the emergence of indigenous guardians in the literature and explore whether guardian approaches are representative of Indigenous approaches to environmental governance. Using a multistep relevance-screening method, we reviewed 83 articles published since 1995, that report on, critique, or comment on Indigenous guardians. Our findings indicated that most articles on the topic were published in the last decade (88%), focused on Australia (65%), and were in a social science discipline (53%). The lead author of the majority of articles was an academic, although only half of the articles included an indigenous scholar or member of an indigenous group or organization as a coauthor. Finally, 11 articles were on research of guardian programs that were locally led and only 5 exemplified indigenous governance, based on 2 well-known community-based monitoring typologies. Our findings indicate that more research is required to understand the implications of current guardian programs for indigenous self-determination, particularly when such programs are embedded in a broader western environmental governance structure. 相似文献
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Esmail Amiri 《Environmental and Ecological Statistics》2014,21(1):125-141
Atmospheric carbon dioxide concentration (ACDC) level is an important factor for predicting temperature and climate changes. We analyze the conditional variance of a function of ACDC level known as ACDC level growth rate (ACDCGR) using the generalised autoregressive conditional heteroskedasticity (GARCH) and GARCH models with leverage effect. The data are a subset of the well known Mauna Loa atmosphere carbon dioxide record. We test for the presence of stylized facts in the ACDCGR time series. The performance of GARCH models are compared to EGARCH, TGARCH and PGARCH models. Model fit measures AIC, BIC and likelihood is calculated for each fitted model. The results do confirm the presence of some of important stylized facts in the ACDCGR time series, but the presence of leverage effect is not significant . The out of sample one step ahead forecasting performances of the models based on RMSE and MAE metrics are evaluated. EGARCH model with student $t$ disturbances showed the best fit and a valid forecasting performance. A bootstrap algorithm is employed to calculate confidence intervals for future values of ACDCGR time series and its volatility. The constructed bootstrap confidence intervals showed a reasonable performance. 相似文献
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Three shell-shape parameters of Littorina saxatilis were measured and found to vary in a regular pattern with distance up an estuary. The translation rate of the shell increased, the rate of whorl expansion decreased and the circularity of the aperture decreased proceeding from the exposed shore to the protected shore. The genetic variance of these traits was estimated from the full-sib covariance and the motheroffspring covariance. The genetic variance of the translation rate and the circularity of the aperture was low in all populations, but the genetic variance of the rate of whorl expansion was high on the exposed shore and low on the protected shore. It is argued that the change in mean phenotype of these traits is the result of natural selection produced by varying degrees of wave action and desiccation. The observed genetic variance is consistent with the theory that a trait under selection will show little additive genetic variance. 相似文献
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Ioanna Katsiadaki Matthew Sanders Marion Sebire Masaki Nagae Kiyoshi Soyano Alexander P Scott 《Environmental sciences》2007,14(5):263-283
The three-spined stickleback, a small teleost species with habitats that range from full marine to fresh water bodies across the whole Northern hemisphere, has a number of advantages for endocrine disruption research. It is the only teleost species with an unambiguous biomarker for androgens, the presence of the glue protein spiggin in the male kidney, which can be measured by enzyme-linked immunosorbent assay (ELISA). The androgen assay has been adopted to detect antiandrogens in two different ways and an homologous ELISA for stickleback vitellogenin is also available. DNA markers for molecular sex determination are available; thus, sex ratios can also be used for in situ biomonitoring. In addition, the critical period of sexual differentiation has been determined and the occurrence of intersex fish has been reported several times. The species full genome sequence is almost complete. All aspects of stickleback biology (ecology, evolution, behavior, physiology, endocrinology) are well documented. In European waters, the stickleback is the only fish that can bring laboratory and field studies together and allow the true impact of endocrine disruptors on fish populations to be evaluated. 相似文献
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This paper seeks to construct some theoretical tools that can be used to examine formally the equity issues raised in the use of pricing as a means to conserve scarce resources, in particular, the criteria that can be used to judge the equity of such a price change and the special problem raised by differences in elasticity of demand of different customer groups are considered. Toward this end the concept of a “superfair” distribution (a distribution under which each and every participant obtains a share of the total which is equal to or greater than that individuars pro-rata share, in his own estimation) is introduced and discussed. 相似文献
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Ričardas Taraškevičius Rimantė Zinkutė Laura Gedminienė Žilvinas Stankevičius 《Environmental geochemistry and health》2018,40(5):1817-1840
The research is based on analysis data of Cr, Cu, Mn, Ni, V, Zn (metals) and S in the hair of 47 girls and 63 boys from eight Vilnius kindergartens and the distribution pattern of high metal concentrations and bioavailability in snow-cover dust, also dust samples from vents of characteristic pollution sources. The kindergartens were selected according to topsoil total contamination index and dust-related indices. Significantly higher Cu, Mn, Ni and Zn concentrations in the hair of girls (means are 1.1, 1.9, 1.3, 1.2 times higher) and the differences between hair of genders according to inter-element correlation and clustering were found. Analysis of Spearman correlation coefficients between metal concentrations in hair of each gender and dust metal concentrations or metal loading rates at their residence sites revealed that for Mn, Cu and Zn, they are insignificant, while for Cr, Ni, Pb and V, they are mainly significant positive (except V in female hair). The correlation of the contents of Cr, Ni and V in dust with respective concentrations in hair was more significant for boys (p < 0.001) than for girls. Only a few cases with a significant Cr, Ni, Cu, Pb and Zn increase were revealed in hair of children attending polluted kindergartens in comparison with control. It was concluded that relationship between metal concentrations in hair and dust-related indices is more expressed for children’s residence sites than for their kindergarten sites. The gender-based grouping and site-by-site study design are recommended in the studies of reflection of environmental exposure in hair. 相似文献
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The utility of systems diagrams and of energy as a unit of measure for environmental impact assessment is illustrated using results from the White Sands Missile Range, New Mexico Environmental Impact Statement. A set of procedures for developing and evaluating the diagrams is given and applied to White Sands. The utility of results obtained using this method is compared to those obtained from other methods, and the inadequacies of each are discussed.These procedures guide data collection; organize and summarize data; make explicit interactions between the environment and the “proposed project”; place various kinds of impacts and alternatives in perspective with each other and with the entire system; identify components of a macroscale system which need microscale analysis; and permit quantification of total impact and quantitative comparisons of impact types, of alternatives, and of environmental control strategies. The procedures do not guarantee that important impacts have not been overlooked, do not deal with so called aesthetic impacts, and do not guarantee that the appropriate system boundary has been chosen.Impacts at White Sands were evaluated at two system levels of detail. At a macroscale, five types of impacts resulting from missile range activities were analyzed. Results indicated that stresses on the environment caused by those activities represent 1.0% of the natural energy flow through the system. At a more detailed level of analysis, the effect of water consumption by the Missile Range on the aquifer from which the water is obtained was analyzed by means of a hydrologic model. Model simulations indicated that salt water intrusion into the aquifer was eminent and identified two aquifer management strategies that could prevent that intrusion. 相似文献
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The optimal pricing of pollution when enforcement is costly 总被引:3,自引:0,他引:3
John K. Stranlund Carlos A. Chvez Mauricio G. Villena 《Journal of Environmental Economics and Management》2009,58(2):183-191
We consider the pricing of a uniformly mixed pollutant with a model of optimal, possibly firm-specific, emissions taxes and their enforcement under incomplete information about firms’ abatement costs, enforcement costs, and pollution damage. We argue that optimality requires an enforcement strategy that induces full compliance by every firm, except possibly when a regulator can base the probabilities of detecting individual violations on observable correlates of violators’ actual emissions. Moreover, optimality requires discriminatory taxes, except when a regulator is unable to use observable firm-level characteristics to gain some information about the variation in firms’ abatement costs or monitoring costs. 相似文献