In Pursuit of Safety: One-Hundred Years of Toxicological Risk Assessment

The publication in 1962 of Rachel Carson's Silent Spring marks the mid-point in a century that saw, in its first half, the emergence of public health concerns related to human exposures to chemicals, and, in its second half, the emergence of public policies to deal with those concerns. Those policies made it imperative that the scientific community come to grips with the problem of identifying exposure levels not likely to cause harm. This problem was not significantly discussed within the scientific community until the 1950s, and well-described methods for practical solutions to it did not appear until the 1970s. An important report from the National Academy of Sciences, published in 1983 (Risk Assessment in the Federal Government), provided an analysis of these emerging methods, and recommended a useful framework for the assessment and management of risk. This framework remains central to public health and regulatory decision-making. A high-level perspective is offered on events leading to and following the 1983 report. The article describes early thinking about chemical toxicity and the scientific path that thinking followed through the 20th century, and to the present.     

On the Application of Fuzzy Decision Theory in Chemotherapy

1IntreductionTheliteratUreonmulti-Criteriondecisionmaking(MCDM)problemshas~tremendouslyintherecentpast.TwomajorareashaveevolvedwhiChbothconcentrateondecisionmakingwithseveralcriteria:multiobjectivedecisionmaking(MODM)andmulti-attributedecisionmaking(MADM).TheformerconcentratesoncontinuousdecisionspaceandthelatterfocusesonproblemswithdiscreteSPace.FuzzysettheoryhascontributedtoMODMproblemsaswellastheMADMProblems.ThegeneralMODMproblemcanbedeft.edLllasfollows:Twostagescangenerallybe…     

Ants resort to majority concession to reach democratic consensus in the presence of a persistent minority

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Labor specialization and the formation of markets for food in a Shipibo subsistence economy

Traditionally, the Shipibo economy was subsistence-based with shifting cultivation supplying calories, principally in the form of plantains and root crops, while fishing and hunting provided animal proteins to the diet. Some men, who recently began producing rice for sale in regional markets, now allocate less time to wild food procurement. Moreover, this trend has been accompanied by the nucleation of households, a growing cash market for agricultural labor, and the intravillage sale of faunal foods. This paper shows that with cash cropping, some Shipibo now freely distribute less food to others in relation to the amount they produce. To account for this change, a theory is developed based on time allocation and patterns of economic behavior reported throughout the Amazon. This theory is then applied to explain specialization and the formation of cash markets for food labor among the Shipibo.     

Settler agriculture and the dynamics of resource allocation in frontier environments

This article attempts to conceptualize the dynamics of resource allocation by colonist farmers under the unique conditions of land abundance and labor scarcity which characterize frontier environments, such as the smallholder agricultural settlement areas in the Amazon basin. In contrast, most previous theoretical literature on household agricultural decision making and land-use change in rural areas considers conditions of high population density and land scarcity, and is not, therefore, adequate for understanding critical land-use changes which may be occurring in frontier regions. This article first discusses the appropriateness and inadequacies of the analytical frameworks commonly used to explain the expansion of settler agriculture into remote forest regions and the unsustainable land-use practices observed in these areas. This review serves as the basis for characterizing resource allocation under the particular conditions of frontier environments. A conceptual advance in the analysis is its consideration of the way institutional/policy factors and farm-level characteristics can interact to produce land-use outcomes. This knowledge is essential to understand not only the social and economic factors affecting present land use and choice of technology, but also those factors influencing farmers' demand for more optimal systems of land use which are consistent with varying agro-ecological potentials, demographic situations, and their own management capacity.     

Mobility and cooperation among nomadic shepherds: The case of theRaikas

This paper describes and then analyzes the decision-making arrangements that prevail among the Raikas—nomadic shepherds from Western India. The paper suggests, using a simple analytical framework, that the existing distribution of decision-making during migration helps the Raikasto utilize available economies of scale, represent the different interest groups in their collectives, and control their decision-makers. At the same time, the ordinary shepherds in the camp are able to extract a comfortable subsistence from a complex and harsh environment by delegating much of their decision-making responsibilities to the leaders in the camp. To the extent shepherds in other parts of the world migrate over long distances and must confront similar issues of delegation of responsibilities and control over decision-makers, the analysis holds general relevance.     

Mechanisms of group-hunting in vertebrates

Group-hunting is ubiquitous across animal taxa and has received considerable attention in the context of its functions. By contrast much less is known about the mechanisms by which grouping predators hunt their prey. This is primarily due to a lack of experimental manipulation alongside logistical difficulties quantifying the behaviour of multiple predators at high spatiotemporal resolution as they search, select, and capture wild prey. However, the use of new remote-sensing technologies and a broadening of the focal taxa beyond apex predators provides researchers with a great opportunity to discern accurately how multiple predators hunt together and not just whether doing so provides hunters with a per capita benefit. We incorporate many ideas from collective behaviour and locomotion throughout this review to make testable predictions for future researchers and pay particular attention to the role that computer simulation can play in a feedback loop with empirical data collection. Our review of the literature showed that the breadth of predator:prey size ratios among the taxa that can be considered to hunt as a group is very large (<10⁰ to >10²). We therefore synthesised the literature with respect to these predator:prey ratios and found that they promoted different hunting mechanisms. Additionally, these different hunting mechanisms are also related to particular stages of the hunt (search, selection, capture) and thus we structure our review in accordance with these two factors (stage of the hunt and predator:prey size ratio). We identify several novel group-hunting mechanisms which are largely untested, particularly under field conditions, and we also highlight a range of potential study organisms that are amenable to experimental testing of these mechanisms in connection with tracking technology. We believe that a combination of new hypotheses, study systems and methodological approaches should help push the field of group-hunting in new directions.     

灰色多目标局势决策在晋西北植树造林中的应用

采用灰色多目标局势决策方法确定了晋西北地区不同土地类型上的最佳造林树种．在梁峁坡地、阴沟坡地、阳沟坡地和河滩地上的最佳造林树种分别是柠条、油松、刺槐和杨树     

Moral Darwinism: Ethical evidence for the descent of man

Could an ethical theory ever play a substantial evidential role in a scientific argument for an empirical hypothesis? InThe Descent of Man, Darwin includes an extended discussion of the nature of human morality, and the ethical theory which he sketches is not simply developed as an interesting ramification of his theory of evolution, but is used as a key part of his evidence for human descent from animal ancestors. Darwin must rebut the argument that, because of our moral nature, humans are essentially different in kind from other animals and so had to have had a different origin. I trace his causal story of how the moral sense could develop out of social instincts by evolutionary mechanisms of group selection, and show that the form of Utilitarianism he proposes involves a radical reduction of the standard of value to the concept of biological fitness. I argue that this causal analysis, although a weakness from a normative standpoint, is a strength when judged for its intended purpose as part of an evidential argument to confirm the hypothesis of human descent.