Reference values for trace and ultratrace elements in human serum determined by double-focusing ICP-MS

Reference values for trace and ultratrace elements concentrations in healthy human serum, measured by double-focusing inductively coupled plasma-mass spectrometry (ICP-MS), are presented. Blood donors from Asturias (Spain) were selected as the reference population (n=59). Blood samples were collected, after donation, taking the necessary precautions to avoid contamination. All subjects analyzed had normal renal function and nutritional status, as shown from their creatinine and albumin levels. A total number of 14 elements (Al, Ca, Cr, Mn, Fe, Co, Cu, Zn, Rb, Sr, Mo, Cd, Pb, and U) were monitored almost simultaneously. Serum samples were diluted 1+4 with ultrapure water and matrix interferences were corrected using Sc, Ga, Y, and Tl as internal standards. Fe, Cu, and Zn were also determined by isotope dilution analysis (IDA). Reference trace element concentrations intervals observed containing 95% of the reference distribution after excluding outliers are presented. Fourteen serum samples from hemodialysis patients were also analyzed for comparison. High levels of Al, Cr, Sr, Mo, Mn, Pb, U, Co, and Cu and low levels of Fe, Zn, and Rb were found in the serum samples from hemodialysis patients compared to the corresponding reference values observed in this work.     

Reference values of selenium in plasma in population from Barcelona. Comparison with several pathologies

Plasma selenium reference values from healthy donors in the metropolitan area of Barcelona are determined. A random sample from 156 healthy adults (control group) is analysed by using electrothermal atomic absorption spectrometry with Zeeman effect background correction.

The relationship between several pathologies and Se content is also evaluated. Se content from 64 samples from subjects with chronic renal failure and 54 from subjects suffering from several malignancies are determined and the results are compared to the reference values. Moreover, Se contents are determined and compared in two groups of children, healthy (19 samples) and children of mothers infected with HIV-1 (16 samples).

In the control group, Se plasma concentration ranges between 50 and 145 μg · L⁻¹ (82.2 ± 17.5 μg · L⁻¹). Significantly lower values are found in the two pathologies studied (malignancy and chronic renal failure), compared to the control group. However, no significant differences in Se content are found between the two groups studied regarding malignancy and chronic renal failure.

In children of mothers infected with HIV-1, Se status is significantly lower than that of healthy children.     

Species Sensitivity Distributions Revisited: A Critical Appraisal

We revisit the assumptions associated with the derivation and application of species sensitivity distributions (SSDs). Our questions are (1) Do SSDs clarify or obscure the setting of ecological effects thresholds for risk assessment? and (2) Do SSDs reduce or introduce uncertainty into risk assessment? Our conclusions are that if we could determine a community sensitivity distribution, this would provide a better estimate of an ecologically relevant effects threshold and therefore be an improvement for risk assessment. However, the distributions generated are typically based on haphazard collections of species and endpoints and by adjusting these to reflect more realistic trophic structures we show that effects thresholds can be shifted but in a direction and to an extent that is not predictable. Despite claims that the SSD approach uses all available data to assess effects, we demonstrate that in certain frequently used applications only a small fraction of the species going into the SSD determine the effects threshold. If the SSD approach is to lead to better risk assessments, improvements are needed in how the theory is put into practice. This requires careful definition of the risk assessment targets and of the species and endpoints selected for use in generating SSDs.     

Herbivore and pathogen damage on grassland and woodland plants: a test of the herbivore uncertainty principle

Researchers can alter the behaviour and ecology of their study organisms by conducting such seemingly benign activities as non-destructive measurements and observations. In plant communities, researcher visitation and measurement of plants may increase herbivore damage in some plant species while decreasing it in others. Simply measuring plants could change their competitive ability by altering the amount of herbivore damage that they suffer. Currently, however, there is only limited empirical evidence to support this `herbivore uncertainty principle' (HUP). We tested the HUP by quantifying the amount of herbivore and pathogen damage in 13 plant species (> 1400 individuals) at four different visitation intensities at Cedar Creek Natural History Area, Minnesota, USA. Altogether, we found very little evidence to support the HUP at any intensity of visitation. Researcher visitation did not alter overall plant herbivore damage or survival and we did not detect a significant visitation effect in any of the 13 species. Pathogen damage also did not significantly vary among visitation treatments, although there was some evidence that high visitation caused slightly higher pathogen damage. Based on our results, we question whether this phenomenon should be considered a `principle' of plant ecology.     

Integrating biodiversity priorities with conflicting socio-economic values in the Guinean–Congolian forest region

Identifying important areas for conserving biodiversity has attracted much discussion, but relatively few studies have dealt with conflicting socio-economic interests in a manner that is fully accountable. For the Guinean–Congolian forest region, we applied quantitative methods to select a network of coarse-scale areas sufficient to represent all forest mammal and bird species at least once. In a separate exercise, we prioritised 50% of the region to represent the same species as many times as possible. In both cases, we sought to minimise potential conflicts between conservation and other socio-economic imperatives by considering benefit-to-cost ratios. We found that by choosing areas to reduce conflicts, we were able to increase markedly the proportion of selected areas with low or medium conflict and decrease the proportion with high conflict. Nonetheless, we cannot expect that conservation goals will always be met unless some of these conflicts are faced and resolved. By working together with specialists from both the biological and socio-economic fields, we show that easily implemented quantitative tools could be useful for supporting the process of finding important areas for biodiversity conservation, while avoiding much of the conflict with other interests.     

Incorporating Science,Technology, Fairness,and Accountability in Environmental,Health, and Safety Decisions

The Precautionary Principle is in sharp political focus today because (1) the nature of scientific uncertainty is changing and (2) there is increasing pressure to base governmental action on more “rational” schemes, such as cost-benefit analysis and quantitative risk assessment, the former being an embodiment of ‘rational choice theory’ promoted by the Chicago school of law and economics. The Precautionary Principle has been criticized as being both too vague and too arbitrary to form a basis for rational decision making. The assumption underlying this criticism is that any scheme not based on cost-benefit analysis and risk assessment is both irrational and without secure foundation in either science or economics. This paper contests that view and makes explicit the rational tenets of the Precautionary Principle within an analytical framework as rigorous as uncertainties permit, and one that mirrors democratic values embodied in regulatory, compensatory, and common law. Unlike other formulations that reject risk assessment, this paper argues that risk assessment can be used within the formalism of tradeoff analysis—a more appropriate alternative to traditional cost-benefit analysis and one that satisfies the need for well-grounded public policy decision making. This paper will argue that the precautionary approach is the most appropriate basis for policy, even when large uncertainties do not exist, especially where the fairness of the distributions of costs and benefits of hazardous activities and products are a concern. Furthermore, it will offer an approach to making decisions within an analytic framework, based on equity and justice, to replace the economic paradigm of utilitarian cost-benefit analysis.     

On the Even Greater Need for Precaution Under Global Change

The greater the potential for disastrous, large-scale, or catastrophic impacts on health, the greater the case for precaution. The imperative for precautionary action, critical also for downstream determinants of health, is at least as compelling where macro-level concerns about the sustainability of life on Earth are at issue. In this context, I propose that a higher threshold of uncertainty is needed where large-scale harms to health and well-being are possible. Initial efforts must focus on the training of researchers and risk managers for competencies in complexity, and in systems approaches to transdisciplinary enquiry. Revisiting the intent behind Bradford Hill on causation is an essential first step. Focus on the more proximate causes of diseases, such as those related either to occupational exposures or to more downstream environmental exposures, is left to others in this collection.     

略论中国园林观赏昆虫的美学价值

对中国园林中栖息于不同植物群落的观赏昆虫主要类群及其美学价值进行了初步探析;简析了审美意识与审美主体及时空的关系;并对如何进一步能动地利用观赏昆虫去丰富、补缀、显豁园林的美学价进行了探讨。     

当归栽培及加工技术

本文对当归的形态特征、分布区域、药用价值,特别是当归的栽培及加工技术进行了详细的论述,以期为当归的生产提供一项实用技术.