Trade-offs between time, predation risk and life history, and their implications for biogeography: A systems modelling approach with a primate case study

Group sizes are often considered to be the result of a trade-off between predation risk and the costs of feeding competition. We develop a model to explore the interaction between different ecological constraints on group sizes, using a primate (baboons) case study. The model uses climatic correlates of time budgets to predict maximum ecologically tolerable group size, and climatic predictors of predation risk (reflected mainly in predator density and female body mass) to predict minimum tolerable group size for any given habitat. As well as defining the range of sustainable group sizes for a given habitat, the model also allows us to reliably predict our exemplar taxon's biogeographical distribution across Africa. We also explore the life history implications of the model to ask whether baboons form group sizes which maximise survival or fecundity in the classic trade off between these two key life history variables. Our results indicate that, within the range of study sites in our sample, baboons prefer to maximise fecundity. However, the data indicate that in higher predation risk habitats they would switch to maximising survival at the expense of fecundity. We argue that this is due to the fact that interbirth interval and developmental rates have a ceiling that cannot be breached. Thus, while females can shorten interbirth intervals to compensate for increased predation risk, there is a limit to how much these life history variables can be altered, and when this is reached the best strategy is to maximise survivorship.     

煤矿事故中生命价值经济评价探讨

我国每年都有大量的煤矿事故发生 ,造成数千名矿工死亡 ,对死亡矿工的经济赔偿 ,往往是事故处理的一大难题 ,其主要原因是目前对死亡矿工的赔偿标准偏低。由于赔偿费用低 ,经济赔偿的代价不足 ,以引起威慑和警戒 ,部分煤矿企业仍然不重视安全生产、不珍惜矿工生命 ,从而煤矿伤亡事故不断发生。分析了目前国内外主要的生命价值评价方法和评价结果 ,对煤矿事故中的生命价值进行了研究 ,提出采用净产值推算矿工的生命价值 ,并给出了相应的计算公式和分析实例。分析结果表明 ,目前的赔偿标准不能体现矿工的生命价值 ,二者之间存在相当大的差距     

中国杀虫剂类持久性有机污染物的生命周期管理

中国已签署《关于持久性有机污染物的斯德哥尔摩公约》。面对目前杀虫剂类持久性有机污染物 (POPs)的生产、使用和环境污染现状 ,中国履约形势十分严峻。笔者探讨了生命周期管理的概念 ;分析了污染历史、现状和原因 ;提出了杀虫剂类POPs在生产、运输、销售、使用、库存和废弃处置等阶段的生命周期管理建议 ;指出相关法律、法规和制度的建立和执行应体现源头控制、优先控制和生命周期管理的思想。     

Recycling, landfill consumption, and CO2 emission: analysis by waste input–output model

The emission of waste in an economy, including landfill, is to a large extent determined by its patterns of technology, institutions, and lifestyle. A mathematical model (the waste input–output model) is presented that gives a simple analytical representation of this interdependence. The model was used to evaluate the effects of alternative waste disposal and recycling options on the levels of industrial production, landfill consumption, and the emission of carbon dioxide, and also to analyze the overall dependence on landfill of individual industries. It was found that a systematic combination of the options could be effective in reducing the overall landfill consumption and carbon dioxide emission. Received: November 4, 2000 / Accepted: August 2, 2001     

生命周期评价在过程工业用水网络设计中的应用

介绍了考虑环境因素的过程工业用水网络设计研究进展,分析了典型的过程工业水系统的特点,肯定了在整个水系统生命周期内考察用水网络设计方案环境效益的重要性,给出了生命周期评价方法在用水网络设计中应用的技术框架。     

Managing Tree-of-Heaven (Ailanthus altissima) in Parks and Protected Areas: A Case Study of Rondeau Provincial Park (Ontario, Canada)

The Carolinian Life Zone in southwestern Ontario, Canada is valued because it represents an almost disjunct ecosystem (i.e., one that is typical of the mid-Atlantic United States, rather than the rest of Canada or the nearby states in the United States). The landscape of the Carolinian Life Zone has undergone dramatic transformation, especially in recent decades as agriculture, urbanization, and recreation have intensified. One of the most apparent changes is the invasion of exotic plant species that exacerbates the need for mass restoration efforts. Within the Carolinian Life Zone, Rondeau Provincial Park has experienced an influx of nonindigenous, invasive species in recent years. Tree-of-heaven (Ailanthus altissima) is one example. The infestation is still relatively localized to (mainly) the park, slowly spreading, and manageable as long as something is done immediately. We examined the effects of hand-pulling and mulching, cut stump and glyphosate application, cut stump alone, and the EZJect Capsule Injection System (using glyphosate) on the management of A. altissima within the park. Cut stump and glyphosate treatment was most effective and efficient in its control of young A. altissima shoots because it limits disturbance and has acceptable capital and operating costs. Hand-pulling and mulching was the second choice, mainly because of the risk of additional disturbance that increased shoot densities 1 year after treatment. Cut stump alone was not effective, worsened the infestation, and is not recommended for this species. The EZJect system was effective at managing mature, seed-producing shoots, although the somewhat higher capital costs mean that the system probably should be purchased for management of several invasive tree species to make it more cost-effective.     

Guidelines for life extension process management in oil and gas facilities

Facilities life extension has caught the attention among the capital-intensive industries, like oil and gas. By extending the life cycle of the industrial assets, a wide range of benefits is obtained, comparing with other life ending management strategies. This article first contextualizes the implementation of the life extension concept in the oil and gas industry, showing global data about life extension. Despite the importance of the ageing process, due to its great economic impact and the risk it poses to the production sector, regulatory entities, even in countries more advanced in that sector or that have already experienced the extension process, developed only superficial material about the topic without defining a structured methodology for the assessment of the possibility of useful life extension. The available references do not allow a comprehensive analysis of that possibility, which highlights the importance the methodology proposed. Thus, this article proposes a guideline for the life extension process management, strengthening a framework containing the main evaluation stages, aiming to facilitate the analysis of issues related to ageing and to support the decision-making process. Lastly, real case studies regarding current life extension processes submitted to the Brazilian regulatory body were evaluated against the proposed framework stages, evidencing their lack of necessary details to support the decision-making. Upon the realization that the real cases identified do not allow for the assessment of the contribution and adequacy of the proposed framework in its entirety, the same was also applied to a hypothetical case. The latter was developed based on facts reported by a major operator in Brazil. The result was the determination that the use of the proposed methodology transformed the assessment of the possibility of life extension into a systematic and transparent process, leading to easier and better-founded decision-making procedures, and improving the management of the asset during its extended life.     

The effect of the exposure time on the value of a manSievert averted

The basis of the manSievert as a unit for collective radiation dose is discussed and previous recommendations are considered for how much should be spent to avert a collective dose of 1 manSv. New calculations are given using the J-value method. It is shown that the value to be assigned to averting a manSievert depends on the duration of averted exposure as well as on the net discount rate and the loan rate thought to be appropriate. Different figures will result depending on whether the exposed group consists of workers or the general public. The variation with dose duration is so large that it is not possible to recommend a single figure for the value of a manSievert. Instead, tables are given at two conservative, loan and net discount rates for the value of a manSievert as a function of exposure time. The base data for the J-value method need to be updated annually, and this means that the values given in the tables will increase over time as people live longer and become richer.     

Potential re-colonisation by cladocerans of an acidic tropical pond

To predict how re-colonisation of acidified lakes will proceed, at least two approaches are possible: (i) to compare the life history traits of candidate species and determine which one has the highest fitness, and (ii) to simulate a more realistic scenario carrying out experiments with the grouping of the candidate species, so that the intrinsic rate of natural increase of each species is integrated with its sensitivity to low pH and its ability to compete with the other candidate populations. The objective of the present study was to investigate the future re-colonisation of such acidified systems, taking as case-study a tropical pond (Lagoa das Dunas, Camaçari, BA, Brazil) and four species of cladocerans occurring in nearby water bodies (Ceriodaphniacornuta, Ceriodaphniasilvestrii, Latonopsisaustralis and Macrothrix elegans), by comparing the two above mentioned approaches. The second approach included two sets of in situ microcosms experiments, one simulating the re-colonisation by immigrating ephippia, thus using neonates of each species as colonisers, and another simulating the immigration of adults. Both these simulations followed nearly the same trends. The integration of the effects of a higher temperature, a different photoperiod and species competition determined differences in the species densities ranking between the two approaches: life history versus microcosms. The densities of C.cornuta in the microcosms matched the biphasic concentration/response hormetic model, in the simultaneous presence of two increasingly intense stressors (interspecific competition and acidity), with a low-dose stimulation and a high-dose inhibition. The present study provided, thus, a further support to the acceptance of hormesis in ecotoxicology, also at the population level in multispecies experiments.