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Knowledge of the level of natural uranium (U) in the human body is fundamental in order to estimate the potentially hazardous incorporation in accidentally exposed subjects. A constant monitoring of exposed workers needs reliable reference baseline values, which can be determined by measuring the U concentration in urine. ICPMS has proven to be a fast, reliable and highly sensitive technique for this purpose. Non-uniformity in the distribution of U levels in various regions and differences in dietary habits account for the significant regional variations of U concentration in urine in non-exposed subjects. In this paper, the determination of daily uranium urinary excretion levels in a group of 12 non-exposed subjects from Northern Italy is presented and compared to data present in the published literature and to values obtained in a larger group of German volunteers. The urinary U output values observed in the Italian subset are generally higher than the corresponding levels measured in other groups. This could be the result of a higher intake of U from liquids, as assessed by the determination of U concentration in drinking waters.  相似文献   
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The Palmerton Zinc Site is a Superfund site in Palmerton, Pennsylvania. Its former mineral processing operations have contaminated nearby wells and soils with zinc and cadmium. Preliminary analysis of soil and dust sampling conducted in May 1991 has revealed that the dust poses a potential threat to human health. Based on the results of a previous study, which showed a high percentage of silt and clay in soils from Palmerton residential properties, it was concluded that soil washing is not likely to be a viable method to treat the soil and dust contamination in Palmerton. However, since the completion of this study, a soil-washing process for “unwashable” clays and silts has been developed. A residential soil sample from Palmerton, which had low concentrations of arsenic, cadmium, and lead, and a somewhat high concentration of zinc, was washed in a bench-scale version of this process. The results showed that the new soil-washing process for “unwashable” clays and silts may be a viable method to treat the soil and dust contamination in Palmerton, depending on the soil quality criteria concentrations selected for site cleanup.  相似文献   
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A number of EU institutions and government committees across Europe have expressed interest in developing methods and decision-support tools to facilitate consideration of the ethical dimensions of biotechnology assessment. As part of the work conducted in the EC supported project on ethical tools (Ethical Bio-TA Tools), a number of ethical frameworks with the potential to support the work of public policy decision-makers has been characterized and evaluated. One of these potential tools is the Delphi method. The Delphi method was originally developed to assess variables that are intangible and/or shrouded in uncertainty by drawing on the knowledge and abilities of a diverse group of experts through a form of anonymous and iterative consultation. The method has hitherto been used by a diversity of practitioners to explore issues such as technology assessment, environmental planning, and public health measures. From the original (classical) Delphi, a family of Delphi-related processes has emerged. As a result of the evaluation of the various Delphi processes, it is proposed that the classical method can be further developed and applied as a form of ethical framework to assist policy-makers. Through a series of exercises and trials, an Ethical Delphi has been developed as a potential approach for characterizing ethical issues raised by the use of novel biotechnologies. Advantages and disadvantages of the method are discussed. Further work is needed to develop the procedural aspects of the Ethical Delphi method and to test its use in different cultural contexts. However, utilizing an ethical framework of this type combines the advantages of a methodical approach to capture ethical aspects with the democratic virtues of transparency and openness to criticism. Ethical frameworks such as the Ethical Delphi should contribute to better understanding of and decision-making on issues that involve decisive ethical dimensions.  相似文献   
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The assessment of greenhouse gases (GHGs) emitted to and removed from the atmosphere is high on both political and scientific agendas internationally. As increasing international concern and cooperation aim at policy-oriented solutions to the climate change problem, several issues have begun to arise regarding verification and compliance under both proposed and legislated schemes meant to reduce the human-induced global climate impact. The approaches to addressing uncertainty introduced in this article attempt to improve national inventories or to provide a basis for the standardization of inventory estimates to enable comparison of emissions and emission changes across countries. Authors of the accompanying articles use detailed uncertainty analyses to enforce the current structure of the emission trading system and attempt to internalize high levels of uncertainty by tailoring the emissions trading market rules. Assessment of uncertainty can help improve inventories and manage risk. Through recognizing the importance of, identifying and quantifying uncertainties, great strides can be made in the process of Accounting for Climate Change.  相似文献   
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Greenhouse gas intensity is a ratio comparing the greenhouse gas (GHG) emissions of an activity or economic sector to the economic value it generates. In recent years, many countries have calculated the GHG intensity of their economic sectors as a basis for policy making. The GHG intensity of tourism, however, has not been determined since tourism is not measured as an economic sector in the national accounts. While for tourism-reliant countries it would be useful to know this quantity, a number of difficulties exist in its determination. In this study, we determine the GHG intensity of tourism's value added in Switzerland by means of a detailed bottom-up approach with the main methodological focus on how to achieve consistent system boundaries. For comparison, we calculate the tourism sector's GHG intensity for selected European countries using a simpler top-down approach. Our results show that the Swiss tourism sector is more than four times more GHG intensive than the Swiss economy on average. Of all tourism's sub-sectors, air transport stands out as the sector with by far largest emissions (80%) and highest GHG intensity. The results for other countries make similar, if not as pronounced, patterns apparent. We discuss the results and possible mitigation options against the background of the goal to prevent dangerous climate change.  相似文献   
410.
In fish the neuromasts of the lateral line develop as follows: a “migrating primordium” (MP) migrates from the postotic placode along the future posterior lateral line canal to the tail fin. Its placodal cells are assumed to be the basis for the development of the neuromasts. However, an MP was not found in all fish, e.g., in catfish. In the present study, a search was made for the MP in the larvae of the catfish Silurus glanis. Using light and electron microscopy, an MP was found to migrate along the ventral rim of the tail. It precedes the formation of a ventral row of free neuromasts. An MP preceding the main lateral row of the future canal neuromasts was not found. The necessity of the MP for the ventral-free neuromast development is shown by making incisions which block its migration. The result: caudal to the incision site neuromasts do not develop. On the other hand, the same incision procedure applied to the assumed migration route of a—hypothetical—lateral MP does not block the development of the lateral neuromasts. It is concluded that in this case an MP is not necessary for the development of the canal neuromasts.  相似文献   
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