The Legal Regulation of Floats and Gliders—In Quest of a New Regime?

This article analyzes the legal status of unmanned instruments (particularly, floats and gliders) for observation purposes in the ocean environment. These new kinds of instruments are being deployed by the thousands into the oceans, not the least as part of the Argo Project of the International Oceanographic Commission. Their uncontrolled drifting has raised legal questions, especially when such instruments enter waters subject to the jurisdiction of foreign states. The authors argue that the current international legal framework is insufficient to address the pertinent issues, and that a new legal regime is needed.     

The significance of mycotoxins in the framework of assessing workplace related risks

Mycotoxins are fungal metabolite which may in some cases exhibit a high health hazard potential. Mycotoxins can show carcinogenic, mutagenic, toxic, teratogenic or immunotoxic effects. Mycotoxin exposure in the workplace may occur through inhalation and skin contact,e.g. during occupational handling of organic matter such as livestock feed, food products, or waste. Various studies suggest that both acute and chronic effects can occur, depending at least on the exposure level. The magnitude of the potential health risks associated with a respiratory or dermal intake of mycotoxins has largely remained unclear to date. However, according to the directive 2000/54/EC on biological agents and the corresponding German Biological Agents Ordinance, employers are also required to consider the potential hazards posed by toxic effects of biological agents when assessing workplace risks. The aim of this article, therefore, is to present some basis information that should facilitate an evaluation of the significance of mycotoxins in the context of assessing workplace risks. It also provides suggestions for occupational health and safety measures.     

生态意识及其主要特点

一、生态意识产生的时代背景生态意识作为人类思想的先进观念,产生于20世纪后半叶。产业革命以来二百多年,人类依据先进科学技术武装的强大生产力,无限制地向自然进     

Fish community response to the longitudinal environmental gradient in Czech deep-valley reservoirs: Implications for ecological monitoring and management

Ecological quality assessment of non-natural water bodies is, in contrast to natural systems, less developed and requires determining biological indicators that reliably reflect environmental conditions and anthropogenic pressures. This study was motivated to propose fish indicators appropriate for assessment of reservoir ecosystems in central Europe. We analysed changes in water quality, total biomass and the taxonomic, trophic and size composition of fish communities along the longitudinal axes of four elongated, deep-valley reservoirs. Due to high nutrient inputs from their catchments, the reservoirs exhibited pronounced within-system gradients in primary productivity and water transparency. Although fish communities were similar among the reservoirs and dominated by few native species, the community structure and biomass systematically changed along the longitudinal axes of the reservoirs. The biomass and proportion of planktivores/benthivores in the fish community were highest at eutrophic sites near the river inflow and declined substantially towards deep, more oligotrophic sites close to the dam. The biomass and proportion of piscivores significantly increased downstream within the reservoirs alongside improving water quality. At species level, perch Perca fluviatilis and bream Abramis brama responded most sensitively, although in opposite directions, to the longitudinal environmental gradient. The major longitudinal changes in fish community characteristics were found to be consistent between pelagic and benthic habitats. The results of this study suggest that fish communities are appropriate indicators of eutrophication and can be used for ecological quality assessment of non-natural lentic water bodies, such as reservoirs. Moreover, our results underline the necessity to consider within-system gradients in water quality and the fish community when planning sampling programmes for deep-valley reservoirs.     

Ethical Considerations for Outcome‐adaptive Trial Designs: A Clinical Researcher's Perspective

In a typical comparative clinical trial the randomization scheme is fixed at the beginning of the study, and maintained throughout the course of the trial. A number of researchers have championed a randomized trial design referred to as ‘outcome‐adaptive randomization.’ In this type of trial, the likelihood of a patient being enrolled to a particular arm of the study increases or decreases as preliminary information becomes available suggesting that treatment may be superior or inferior. While the design merits of outcome‐adaptive trials have been debated, little attention has been paid to significant ethical concerns that arise in the conduct of such studies. These include loss of equipoise, lack of processes for adequate informed consent, and inequalities inherent in the research design which could lead to perceptions of injustice that may have negative implications for patients and the research enterprise. This article examines the ethical difficulties inherent in outcome‐adaptive trials.     

Examination of the 'founder effect' in biodiversity research: patterns and imbalances in the published literature

We reviewed 2524 articles published from 1987 to 1995 in five international journals, Conservation Biology , Biological Conservation , Biodiversity and Conservation , Ecological Applications , and the Journal of Applied Ecology , to assess patterns and imbalances in biodiversity research in the following subject areas: locations where research was conducted, types of organisms studied, types of ecosystems studied, types of methodologies used, and types of stresses investigated. Biodiversity research was found to be narrowly focused with little deviation from its initial course set of being a discipline concerned largely with the implications of forest habitat loss on charismatic terrestrial megafauna; i.e. the 'founder effect' is very much in evidence. The 'sleeping dragon' of ignored marine biodiversity is really symptomatic of a wider problem, and can perhaps be referred to as a 'hibernating hydra' of many imbalances due to, for example, under-representations of research from developing nations, or on amphibians and invertebrates, alpine and arctic systems, sociological components and chemical stresses etc. It is time to take steps to actively awaken the creature so that conservation biology/applied ecology can become more pluralistic in scope.     

Ecosystem function and species loss – a microcosm study

There are too many kinds of organisms to be able to study and manage each, yet the loss of a single species can sometimes unravel an ecosystem. Such `fusewire species'– critical in the same sense that an electrical fuse can cut out a whole circuit – would be a rewarding focus for research and management effort. However, this approach can only be effective if these `fusewires' represent but a small proportion of the number of species in the system.  

Aim

To demonstrate methods for measuring what proportion of the species in a system are critical to ecosystem function.  

Methods

The prevalence of fusewire species was measured in manipulative experiments on an aquatic microcosm.  

Results

No single genus deletion caused changes in key characteristics of the system.  

Main conclusions

Comparison of these results with other published studies shows that the proportion of critical fusewire species varies amongst different ecosystems. The oxidation pond microcosms were shown to contain no single species indispensable to system function. They appear to be ill-suited to a management strategy which focuses on priority eukaryote species. However, a single study provides no evidence that this result is general or even typical of other kinds of ecosystems; it is presented here as an empirical model. Other methods of investigation are available; they are less experimentally rigorous but more practical. These could provide important guidance in planning an approach to management in a particular ecosystem.     

Assessment of Optimal Selected Prognostic Factors

The identification and assessment of prognostic factors is one of the major tasks in clinical research. The assessment of one single prognostic factor can be done by recently established methods for using optimal cutpoints. Here, we suggest a method to consider an optimal selected prognostic factor from a set of prognostic factors of interest. This can be viewed as a variable selection method and is the underlying decision problem at each node of various tree building algorithms. We propose to use maximally selected statistics where the selection is defined over the set of prognostic factors and over all cutpoints in each prognostic factor. We demonstrate that it is feasible to compute the approximate null distribution. We illustrate the new variable selection test with data of the German Breast Cancer Study Group and of a small study on patients with diffuse large B‐cell lymphoma. Using the null distribution for a p‐value adjusted regression trees algorithm, we adjust for the number of variables analysed at each node as well. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)