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1.
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   
2.
供应链管理中的信息流网络   总被引:6,自引:0,他引:6  
本文对供应链管理中的信息流理论进行了探讨 ,指出了传统链式信息流模式的缺陷 ,分析了简单的网络式信息流模型的构造 ;阐述了信息流网络的特征与优势 ;对若干有待深入研究的问题进行了展望。  相似文献   
3.
论网络社会秩序的维护   总被引:3,自引:0,他引:3  
本文从网络社会秩序的范畴角度入手 ,分析了网络社会秩序维护的必要性 ,并就如何维护问题提出了相关的对策  相似文献   
4.
上海第四制药厂在抗生素生产过程系统节能技术研究中对该厂的热能供应系统提出了3个改造方案.本文以该热力系统为例,通过对各方案的技术经济分析比较,以揭示热力系统经济评估的内在含义,并提出了用参数“净年收益”作为评估依据之一的建议.  相似文献   
5.
本文首次将Elastic Net这种用于高度相关变量的惩罚方法用于面板数据的贝叶斯分位数回归,并基于非对称Laplace先验分布推导所有参数的后验分布,进而构建Gibbs抽样。为了验证模型的有效性,本文将面板数据的贝叶斯Elastic Net分位数回归方法(BQR. EN)与面板数据的贝叶斯分位数回归方法(BQR)、面板数据的贝叶斯Lasso分位数回归方法(BLQR)、面板数据的贝叶斯自适应Lasso分位数回归方法(BALQR)进行了多种情形下的全方位比较,结果表明BQR. EN方法适用于具有高度相关性、数据维度很高和尖峰厚尾分布特征的数据。进一步地,本文就BQR. EN方法在不同扰动项假设、不同样本量的情形展开模拟比较,验证了新方法的稳健性和小样本特性。最后,本文选取互联网金融类上市公司经济增加值(EVA)作为实证研究对象,检验新方法在实际问题中的参数估计与变量选择能力,实证结果符合预期。  相似文献   
6.
Cue-reactivity has received increased attention in addiction research, though not for gambling in particular. We examined cue reactivity in 18 problem gamblers by accompanying them to a gaming casino and measuring their subjective urge to gamble over a 1-h period. Half of the sample was additionally exposed to a gambling-specific negative mood induction (NMI) manipulation via guided imagery. Overall, about two-thirds of the sample reported moderate to high-gambling urges during the casino exposure. Additionally, the NMI reduced cue-reactivity. Finally, gambling urges in both groups decreased over the course of the exposure sessions. These findings suggest that a majority of problem gamblers experience the urge to gamble when exposed to gambling cues and that the intensity of these urges decrease with time, especially in the presence of a gambling-relevant NMI. Cue exposure should be studied further as a potential tool in the treatment of problem gambling.  相似文献   
7.
This paper simultaneously measures the rate of time preference and the coefficient of risk aversion, as well as investigates the interdependencies of four addictive behaviours: smoking, drinking, pachinko (a popular Japanese form of pinball gambling), and horse betting among a sample of the Japanese population. We reach two main conclusions. First, there are significant interdependencies among the four addictive behaviours, in particular between smoking and drinking and between gambling on pachinko and the horses. Second, we conclude that the higher the time preference rate and the lower the risk aversion coefficient becomes, the more likely individuals smoke, drink frequently, and gamble on pachinko and the horses.  相似文献   
8.
网络文化的出现使人类正迈入一个全新的"网络时代",它使大众文化资源和潜力得到了极大限度的发展,并且激活了大众的想象力与创造力,但是与此同时带来了一系列的困难与挑战,如虚拟化的挑战、多元化的挑战、开放性的挑战等。  相似文献   
9.
The focus of this paper is on the notion of 'addictive consumption', conceived as a set of discourses that are embedded within wider socio-historical processes of governance and control. It examines the discursive convergences and conflicts between practices of consumption and notions of addiction, which it notes are consistently represented in terms of the oppositional categories of self-control vs. compulsion and freedom vs. determinism. These interrelations are explored with reference to the development of notions of addiction, and their relation to shifting configurations of identity, subjectivity and governance. Finally, it suggests that the notion of 'addiction' has particular valence in advanced liberal societies, where an unprecedented emphasis on the values of freedom, autonomy and choice not only encourage the conditions for its proliferation into ever wider areas of social life, but also reveal deep tensions within the ideology of consumerism itself.  相似文献   
10.
《成都,今夜请将我遗忘》初在网络亮相登场,引起意想不到的轰动。对这部网络文学作品,本文从结构、语言、主旨三个方面,探查了其成败得失,并对有关的网络文学现象进行了分析。作者认为,该作品有开合有致、驰缓得宜的结构纵深,刚柔相间、沉稳活泼的语言韵味,超越传统、深刻凝重的主旨意义。正是这些原因造就了它的成功。  相似文献   
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