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51.
52.
Quantifying uncertainty in the biospheric carbon flux for England and Wales   总被引:1,自引:0,他引:1  
Summary.  A crucial issue in the current global warming debate is the effect of vegetation and soils on carbon dioxide (CO2) concentrations in the atmosphere. Vegetation can extract CO2 through photosynthesis, but respiration, decay of soil organic matter and disturbance effects such as fire return it to the atmosphere. The balance of these processes is the net carbon flux. To estimate the biospheric carbon flux for England and Wales, we address the statistical problem of inference for the sum of multiple outputs from a complex deterministic computer code whose input parameters are uncertain. The code is a process model which simulates the carbon dynamics of vegetation and soils, including the amount of carbon that is stored as a result of photosynthesis and the amount that is returned to the atmosphere through respiration. The aggregation of outputs corresponding to multiple sites and types of vegetation in a region gives an estimate of the total carbon flux for that region over a period of time. Expert prior opinions are elicited for marginal uncertainty about the relevant input parameters and for correlations of inputs between sites. A Gaussian process model is used to build emulators of the multiple code outputs and Bayesian uncertainty analysis is then used to propagate uncertainty in the input parameters through to uncertainty on the aggregated output. Numerical results are presented for England and Wales in the year 2000. It is estimated that vegetation and soils in England and Wales constituted a net sink of 7.55 Mt C (1 Mt C = 1012 g of carbon) in 2000, with standard deviation 0.56 Mt C resulting from the sources of uncertainty that are considered.  相似文献   
53.
1938年夏天,美国年轻学者科尼利尔斯·奥斯古德为了履行与燕京大学的合作计划,不远万里来到滇池西岸一个名不见经传的小村庄调查.1961年,他开启尘封的笔记本,整理旧资料,补充新文献,完成了<旧中国的农村生活:对云南高峣的社区研究>.70年过去,重温科尼利尔斯·奥斯古德的研究历程,我们仍会从中获得许多有益的启示.  相似文献   
54.
In this work, some corporate websites of the chemical industry of Tarragona (Spain) are studied, analysing how the chemical trade associations and companies present information and/or encourage dialogue with the community on issues relating to the chemical risk and their environmental, health and safety (EHS) performance. The results suggest that the chemical industry in Tarragona uses the corporate websites mainly to disseminate information about its EHS commitments and performance, but they do not encourage dialogue with the community through the Internet.  相似文献   
55.
Over the last ten years in Australia the social component of Australian Environmental Impact statements has gradually increased in size as the importance of Social Impact Analysis has been recognised. This commendable trend has not been without mishap, however, and there remain many areas largely ignored in Social Impact Assessment. This paper seeks to identify these areas, identifying value questions that need to be addressed in the preparation of the social impact component.  相似文献   
56.
We examine the labor-cost savings associated with privatization by comparing earnings and employment trends of public and private sector refuse workers. Findings suggest that high union earnings for workers in the public sector are a source of labor-cost savings in the refuse industry. Evidence on job changers does not indicate that earnings for this group of workers are a compensating differential. Metropolitan area employment findings suggest that municipalities are less likely to use union refuse workers in the public sector when a relatively small percentage of area residents belong to a union. The authors thank Jacqueline Agesa, Keith Bender, Maria Crawford, and Richard Perlman for valuable suggestions. Research assistance from Eric Blackburn is greatly appreciated.  相似文献   
57.
Diagnostics for dependence within time series extremes   总被引:1,自引:0,他引:1  
Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed.  相似文献   
58.
The body is socially constructed; and in this paper we explore the various and ever-changing constructions of the body, and thus of the embodied self, from the Greeks to the present. The one word, body, may therefore signify very different realities and perceptions of reality; and we consider briefly how and why these meanings changed. Plato believed the body was a 'tomb', Paul said it was the 'temple' of the Holy Spirit, the Stoic philosopher Epictetus taught that it was a 'corpse'. Christians believed, and believe, that the body is not only physical, but also spiritual and mystical, and many believed it was an allegory of church, state and family. Some said it was cosmic: one with the planets and the constellations. Descartes wrote that the body is a 'machine', and this definition has underpinned biomedicine to this day; but Sartre said that the body is the self. In sum, the body has no intrinsic meaning. Populations create their own meanings, and thus their own bodies; but how they create, and then change them, and why, reflects the social body.  相似文献   
59.
The paper evaluates the accuracy of Burr approximations of critical values and p-values for test a of autocorrelation and heteroscedasticity in the linear regression model.  相似文献   
60.
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