工业毒物危险度估测的概率模型

本文提出一个危险度估测的对数正态概率模型,用此模型可建立某已知各浓度反应概率资料的反应经典曲线,估测不同浓度下总体的反应概率或个体被侵害的概率、某样本浓度的反应概率及某样本反应概率时的容许平均浓度.     

Palaeolimnological responses of nine North African lakes in the CASSARINA Project to recent environmental changes and human impact detected by plant macrofossil, pollen, and faunal analyses

This paper presents multi-proxy palaeolimnological analyses from recent sediments in the nine CASSARINA lakes in northernmost Africa, three from each of Morocco, Tunisia, and Egypt. The lakes are diverse, ranging from hypersaline to brackish lagoons and fresh-water lakes from high to low conductivity and pH. The macrofossils analysed include fruits, seeds, and vegetative remains of plants, lagoon and fresh-water Mollusca, a range of other aquatic animals, and from one site in each country, Ostracoda and Foraminifera. The diverse macrofossils are multi-proxy indicators of environmental change, and demonstrate changes in response to human activities in the catchments of all the lakes. The three Egyptian Nile Delta lakes have received massive inputs of fresh-water due to modifications of the flow of the R. Nile culminating in the Aswan High Dam built in 1964. Elsewhere, water withdrawal is frequently a serious threat. One lake with high biodiversity in Morocco has been drained and cultivated, and a rare acid-water lake in Tunisia is in danger of drying up. The internationally famous Garaet El Ichkeul in Tunisia, which was so important for birds, has become permanently saline with a loss of diversity. All the lakes are affected by agricultural and/or urban run-off and are experiencing changes as a result of human activities. Several are in a marginally sustainable condition, whereas others are permanently damaged.     

Overexpression of the glucoamylase-encoding STA1 gene of Saccharomyces cerevisiae var. diastaticus in laboratory and industrial strains of Saccharomyces

Production of glucoamylase encoded by the Saccharomyces cerevisiae (var. diastaticus) STA1 gene has been assayed in laboratory S. cerevisiae strains of different ploidy and in different industrial Saccharomyces strains, in which STA1 was expressed under control of an inducible promoter. Highest enzyme activity was achieved with a tetraploid strain constructed by crossing preselected parental strains. Maximal glucoamylase production correlated with heterogeneity in enzyme mass, likely due to incomplete glycosylation, suggesting that the secretion-glycosylation process is the limiting step in the production of the STA-encoded glucoamylase by Saccharomyces. Industrial strains showed quite different capacity to produce glucoamylase. High production was achieved with a S. pastorianus brewer’s strain. Overall, our results allowed the selection of strains capable of yielding a high level of glucoamylase and suggest specific approaches for further enhancing this capability.     

Modelling More Sustainable Aluminium (4 pp)

Goal, Scope and Background This case study describes the development and utilization of a global, quantitative model of current and projected aluminium and life cycle inventory mass flows. The model and key results were developed to be shared with global aluminium industry technical experts, executives, and external stakeholders to better understand potential paths to more global sustainable aluminium. Methods The model is based on annual statistical data since 1950 provided by government agencies and regional aluminum associations and on the most recent life cycle inventory intensity data (year 2002) complied for the global industry by the International Aluminium Institute. Modeling of future aluminium and resource flows are based on literature and industry expert projections of future product shipment demand. The availability of recycle flows to meet these market demands are based on projected utilization, yield, and melt loss recovery rates, post-consumer recycling rates, and anticipated future product lifetimes. The model was developed with quantitative 'what-if' capability to determine the positive impact of enhanced recycling, lower resource intense production, and product usage scenarios. Results and Conclusion The model provides the first quantitative assessment of annual global aluminium and life cycle inventory flows. Results include a quantitative estimate by major market of global aluminium product inventory, system losses, recycle rates, and selected resource requirements and air emissions implications. - Recommendation and Perspective. Model results and scenarios have been reviewed and shared with global aluminium technical leaders, executives and key external stakeholders in support of the International Aluminum Institute's new voluntary global objective to better monitor and enhance aluminium recycling and sustainable development initiative.     

Outcomes of a pilot fish telemetry workshop for developing countries

Fisheries management is a crucial issue worldwide, but it is proportionally more crucial in developing countries that rely heavily on inland fisheries. Management requires proper knowledge of fish behaviour and habitat use, as can be achieved through telemetry techniques, although these are most rarely used in tropical regions. Here we report briefly on the outcomes of a pilot workshop and training course aiming at improving technology transfer and capacity building, laying the stress on strengths and weaknesses of this approach, as evaluated by trainees.     

Molecular cloning of a novel allele of SMR1 which determines sulfometuron methyl resistance in Saccharomyces cerevisiae

Abstract A different mutation ( SMR1B ) to SMR1-410 (ilv2) , which determines resistance to sulfometuron methyl in Saccharomyces cerevisiae , was cloned by PCR. Sequence analysis indicated a C to T change at position 575 of the ILV2 coding sequence, which results in a proline transition to leucine at position 192. Similarly to SMR1-410 , the SMR1B gene was confirmed as a convenient dominant selective marker for yeast transformation including industrial strains.     

Analysis of microbial exopolysaccharides from industrial water systems

Summary The monosaccharide composition of exopolysaccharides extracted from mixed microbial slimes from cooling towers and process waters of paper machines was determined. Gas chromatographic evidence demonstrated that the microbial slimes found in these industrial systems were heteropolysaccharides, each composed of more than one monosaccharide. Monosaccharides identified in deposit samples were glucose, mannose, galactose, rhamnose, fucose, and glucuronic acid. The methods reported allow efficient extraction and analysis of microbial exopolysaccharides, and the results have implications for slime control strategies in industrial systems.     

From Metaphor to Measurement: Resilience of What to What?

Resilience is the magnitude of disturbance that can be tolerated before a socioecological system (SES) moves to a different region of state space controlled by a different set of processes. Resilience has multiple levels of meaning: as a metaphor related to sustainability, as a property of dynamic models, and as a measurable quantity that can be assessed in field studies of SES. The operational indicators of resilience have, however, received little attention in the literature. To assess a system's resilience, one must specify which system configuration and which disturbances are of interest. This paper compares resilience properties in two contrasting SES, lake districts and rangelands, with respect to the following three general features: (a) The ability of an SES to stay in the domain of attraction is related to slowly changing variables, or slowly changing disturbance regimes, which control the boundaries of the domain of attraction or the frequency of events that could push the system across the boundaries. Examples are soil phosphorus content in lake districts woody vegetation cover in rangelands, and property rights systems that affect land use in both lake districts and rangelands. (b) The ability of an SES to self-organize is related to the extent to which reorganization is endogenous rather than forced by external drivers. Self-organization is enhanced by coevolved ecosystem components and the presence of social networks that facilitate innovative problem solving. (c) The adaptive capacity of an SES is related to the existence of mechanisms for the evolution of novelty or learning. Examples include biodiversity at multiple scales and the existence of institutions that facilitate experimentation, discovery, and innovation. Received 20 March 2001; accepted 6 June 2001.