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云南金顶铅锌矿是镉(Cd)元素富集区,采矿活动导致Cd释放出来进入地表环境造成Cd污染。矿区水体中出现较高含量的Cd,高出天然河流中Cd含量的50~100倍。矿区架崖山、北厂和跑马坪等采矿区水体中Cd浓度范围在15~30μg/L之间。矿区水体中Cd含量水平表现为:矿山浅层地下水〉矿山溪流水〉沘江河水。研究结果表明,矿区沘江下游河段水体明显受Cd污染,其中水体中Cd的平均含量为15.7μg/L,悬浮物中Cd含量为49.3mg/kg,沉积物中Cd含量为203.7mg/ks。矿区载Cd岩石和矿物的自然风化是造成矿区水环境中Cd污染的直接原因。

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我国在高放废物深地质处置预选区域的前期研究工作中,已经在地质基础、地壳稳定性、构造格架、地震地质、新构造运动、水文地质、工程地质及关键核素的运移行为等方面取得重要进展.要求更长的安全评价期是上世纪90年代以来,国际公众和社会对高放废物地质处置提出的新要求.因而,有待在较长时间尺度上认识高放废物深地质处置预选区域的环境变化及其对核素迁移行为的可能影响.

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The digital divide continues to challenge political and academic circles worldwide. A range of policy solutions is briefly evaluated, from laissez-faire on the right to “arithmetic” egalitarianism on the left. The article recasts the digital divide as a problem for the social distribution of presumptively important information (e.g., electoral data, news, science) within postindustrial society. Endorsing in general terms the left-liberal approach of differential or “geometric” egalitarianism, it seeks to invest this with greater precision, and therefore utility, by means of a possibly original synthesis of the ideas of John Rawls and R. H. Tawney. It is argued that, once certain categories of information are accorded the status of “primary goods,” their distribution must then comply with principles of justice as articulated by those major 20th century exponents of ethical social democracy. The resultant Rawls-Tawney theorem, if valid, might augment the portfolio of options for interventionist information policy in the 21st century

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http://www.archive.org/details/upanddownnorth00crosrich

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Research on future episodic thought has produced compelling theories and results in cognitive psychology, cognitive neuroscience, and clinical psychology. In experiments aimed to integrate these with basic concepts and methods from autobiographical memory research, 76 undergraduates remembered past and imagined future positive and negative events that had or would have a major impact on them. Correlations of the online ratings of visual and auditory imagery, emotion, and other measures demonstrated that individuals used the same processes to the same extent to remember past and construct future events. These measures predicted the theoretically important metacognitive judgment of past reliving and future "preliving" in similar ways. On standardized tests of reactions to traumatic events, scores for future negative events were much higher than scores for past negative events. The scores for future negative events were in the range that would qualify for a diagnosis of posttraumatic stress disorder (PTSD); the test was replicated (n = 52) to check for order effects. Consistent with earlier work, future events had less sensory vividness. Thus, the imagined symptoms of future events were unlikely to be caused by sensory vividness. In a second experiment, to confirm this, 63 undergraduates produced numerous added details between 2 constructions of the same negative future events; deficits in rated vividness were removed with no increase in the standardized tests of reactions to traumatic events. Neuroticism predicted individuals' reactions to negative past events but did not predict imagined reactions to future events. This set of novel methods and findings is interpreted in the contexts of the literatures of episodic future thought, autobiographical memory, PTSD, and classic schema theory.

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Pathogenic mycobacteria induce the formation of complex cellular aggregates called granulomas that are the hallmark of tuberculosis. Here we examine the development and consequences of vascularization of the tuberculous granuloma in the zebrafish-Mycobacterium marinum infection model, which is characterized by organized granulomas with necrotic cores that bear striking resemblance to those of human tuberculosis. Using intravital microscopy in the transparent larval zebrafish, we show that granuloma formation is intimately associated with angiogenesis. The initiation of angiogenesis in turn coincides with the generation of local hypoxia and transcriptional induction of the canonical pro-angiogenic molecule Vegfaa. Pharmacological inhibition of the Vegf pathway suppresses granuloma-associated angiogenesis, reduces infection burden and limits dissemination. Moreover, anti-angiogenic therapies synergize with the first-line anti-tubercular antibiotic rifampicin, as well as with the antibiotic metronidazole, which targets hypoxic bacterial populations. Our data indicate that mycobacteria induce granuloma-associated angiogenesis, which promotes mycobacterial growth and increases spread of infection to new tissue sites. We propose the use of anti-angiogenic agents, now being used in cancer regimens, as a host-targeting tuberculosis therapy, particularly in extensively drug-resistant disease for which current antibiotic regimens are largely ineffective.

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Book review of: Chance Encounters: A First Course in Data Analysis and Inference by Christopher J. Wild and George A.F. Seber 2000, John Wiley & Sons Inc. Hard-bound, xviii + 612 pp ISBN 0-471-32936-3

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In this past decade finite volume (FV) methods have increasingly been used for the solution of solid mechanics problems. This contribution describes a cell vertex finite volume discretisation approach to the solution of geometrically nonlinear (GNL) problems. These problems, which may well have linear material properties, are subject to large deformation. This requires a distinct formulation, which is described in this paper together with the solution strategy for GNL problem. The competitive performance for this procedure against the conventional finite element (FE) formulation is illustrated for a three dimensional axially loaded column.

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A cytochrome P-450-dependent benzo[a]pyrene mono-oxygenase enzyme system (BPM) has been identified and partially characterized in males of the shore crab Carcinus maenas (L.). Apparent Km values obtained at 30 °C using microsomal preparations from the antennary glands of animals collected during summer were in the range 1.61–2.11 µM. The cytochrome P-450 content was 0·022 nmol/mg microsomal protein when BPM activity in the same preparation was 0·085 nmol/mg protein/min.