Competition and group size in Thomas’s langurs (Presbytis thomasi): the folivore paradox revisited

Among primates, group size is highly variable. The standard ecological model assumes that better predation avoidance as group size increases favours living in larger groups, whereas increased travel costs and reduced net food intake due to within-group competition for resources set the upper limit. Folivorous primates, however, tend to defy this generalisation in that some live in small groups despite low costs of feeding competition. To resolve this ’folivore paradox’, it has been suggested that folivore group size is limited by social factors such as male harassment or infanticide, or that females can disperse more easily and thus maintain group size near optimum levels. In this paper, we examine the effects of group size on home range size, day-journey length, activity budget and diet in wild Thomas’s langurs (Presbytis thomasi), which live in one-male multi-female groups with a limited life cycle. We examined only data from the stable middle tenure phase when factors such as the strength of the breeding male or the way in which groups were formed did not influence ranging and activities. During this phase, group size affected day-journey length and home range size, and had a minor effect on diet, but did not influence time spent feeding or resting, allogrooming or birth rates. Hence the upper limit to group size during the middle tenure phase in Thomas’s langurs is not set by feeding competition. The folivore paradox is not due to frequent female dispersal in Thomas’s langurs. The timing of female dispersal is not as expected if it serves to keep group sizes near the ecological optimum, and groups seem to be below this optimum. Instead, female reproductive success is presumably maximised in small to mid-sized groups because larger groups show a clear trend to experience higher risk of take-over, often accompanied by infanticide. Because females can redistribute themselves among nearby groups when groups reorganise each time a new male starts up a new group, females can keep the group small. Thus, a social factor, risk of infanticide, seems to provide the selective advantage to small group size in Thomas’s langurs. Received: 29 July 1999 / Revised: 17 November 1999 / Accepted: 15 October 2000     

Helpers in colonial cooperatively breeding sociable weavers <Emphasis Type="Italic">Philetairus socius</Emphasis> contribute to buffer the effects of adverse breeding conditions

Some studies on the effects of helpers in cooperatively breeding vertebrates show a positive effect of helper presence on reproductive output whereas others find no effect. One possibility for this discrepancy is that helpers may have a positive effect when breeding conditions are adverse, while their effect might go unnoticed under good conditions. We investigate this hypothesis on sociable weavers Philetairus socius, a colonial cooperatively breeding passerine that inhabits a semi-arid region where breeding conditions vary markedly. We used multivariate mixed models to analyse the effect of helpers on reproduction under contrasting environmental and social conditions while controlling for parental and colony identity. We found that reproductive success in sociable weavers was primarily influenced by nest predation and rainfall. In addition, colony size was negatively associated with hatching and fledging success and number of young fledged per season. Helpers had a less prominent but significant influence on feeding rates and reproductive outcome. In agreement with expectations, the presence of helpers counteracted some of the negative effects of breeding in periods of low rainfall or in large colonies and was also associated with an increased number of young fledged per season. Our results illustrate that the effect of helpers might be detectable mostly under unfavourable conditions, but can contribute to improve reproductive performance in those situations.     

Tracking changes in the global impacts of metal concentrate acquisition for the metals industry in Finland

This article considers the environmental impacts and the governance framework of the domestic and international supply of iron, zinc, copper and nickel concentrates smelted and refined in Finland. The metals industry in the country is heavily dependent on imported concentrates, and the research is thus focused on defining the level of impacts related to mining and mineral processing abroad, and the change in the impacts between 2000 and 2010. The estimations of environmental impacts are based on waste minerals and CO_2eq emissions, and the quality of governance in the set of indicators measuring different aspects of governance. The total amount of waste minerals and CO_2eq emissions related to metal concentrates decreased over the ten-year period. At the same time, the quality of governance improved in all concentrate groups except nickel. Ore grade, mine type and transportation distance appear to be the most influential factors on environmental impacts. The results suggest that the country of origin can have a noticeable effect on the environmental impacts and the quality of governance of the mining and processing of metal concentrates.     

Prenatal diagnosis of Fanconi anemia (Group C) subsequent to abnormal sonographic findings

Manifestations of Fanconi Anemia Complementation Group C (FA-C) include multiple major congenital malformations, hypoplastic radius, absent thumb, growth retardation, elfin-like facial features, microphthalmia, microcephaly, café-au-lait spots, early onset of hematologic disease and poor survival (Auerbach, 1997). We describe two cases in which second-trimester sonographic findings led to parental carrier testing for FA-C and subsequent prenatal diagnosis of affected fetuses. Copyright © 2005 John Wiley & Sons, Ltd.     

Harnessing the bonanza: economic liberalization and capacity building in the mineral sector

Over the past decade many developing and transition economies have liberalized their investment regimes for mining and privatized formerly state-owned mineral assets. In response, these economies have witnessed increased foreign investment in exploration and development, growth in the number and diversity of mineral projects, and the opening up of new channels for harnessing increased economic and social benefits from development in the minerals sector. The restructuring of fiscal and regulatory regimes to encourage foreign investment, and the associated influx of mining capital, technology and skills, is transforming traditional relationships between mining firms, local communities and the government. This transformation necessitates a re-evaluation of the most effective policy approaches to capture increased economic and social benefits from mineral production. This article considers effective mechanisms for improving the capacity of developing and transition countries to maximize the economic and social benefits of mineral production. Common challenges associated with minerals economies are reviewed. Consideration is given to the opportunities for harnessing foreign direct investment and the possibilities for creating new partnerships between local communities, industry, government, and multilateral development agencies through social investment projects. The article concludes with a series of recommendations for the design and implementation of policy approaches towards harnessing mineral production for economic and social benefit following the liberalization of investment regimes for mining.     

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.     

当今采动地层塌陷灾害研究与控制途径

作者论述了采矿引起地层塌陷灾害的严重性，探讨了采动地层塌陷的影响因素，并以此提出当今地层塌陷研究途径和地层塌陷灾害控制技术。     

The resource curse

Countries that possess rich mineral deposits, it is widely assumed, are fortunate. Such deposits are assets, part of a country's natural capital. Mining is the key that converts dormant mineral wealth into schools, homes, ports, and other forms of capital that directly contribute to economic development. Over the past two decades, however, a more negative view of mining has emerged that questions the positive relationship between mineral extraction and economic development. The impetus for the alternative view came from empirical studies suggesting that countries where mining is important have not grown as rapidly as other countries. More recent studies have explored the possible reasons behind the disappointing performance of many mineral producing countries. While the central point of contention between the conventional and alternative views — namely, whether or not mining usually promotes economic development — remains unresolved, there is widespread agreement that rich mineral deposits provide developing countries with opportunities, which in some instances have been used wisely to promote development, and in other instances have been misused, hurting development. The consensus on this issue is important, for it means that one uniform policy toward all mining in the developing world is not desirable, despite the recent suggestions by some to the contrary. The appropriate public policy question is not should we or should we not promote mining in the developing countries, but rather where should we encourage it and how can we ensure that it contributes as much as possible to economic development and poverty alleviation.     

专用铁路开采沉陷信息综合处理系统

依据现行铁路规程、规范 ,以随机介质理论、概率积分法、条件模拟、系统工程方法等为基础 ,应用数据仓库原理、专家系统理论、CAD技术、人机交互技术以及系统集成技术 ,针对专用铁路开采沉陷与治理的特点 ,开发了矿区专用铁路开采沉陷信息综合处理系统 ;实现了实测数据分析与处理、信息预测预报、模型计算、图件绘制、报表与曲线输出、措施知识库管理等的系统化和自动化。笔者介绍了该软件系统的总体目标、系统设计、关键技术及系统构成和主要功能。     

岩层与地表移动控制技术的研究现状及展望

岩层与地表移动控制技术是矿山开采沉陷学的主要研究方向 ,其目的是研究合适的采矿方法和相关技术 ,尽可能地减少岩层和地表移动 ,保护地表建筑物的安全。在综合分析大量文献的基础上 ,从部分开采方法、充填开采方法、覆岩离层注浆和协调开采方法等几个方面对目前岩层与地表移动控制技术的研究现状进行了论述。展望了我国岩层与地表移动控制技术的发展趋势。