High rates of extra-pair young in the pair-living fat-tailed dwarf lemur, Cheirogaleus medius

Cheirogaleids are one of the most primitive extant primate taxa in the world. Their lifestyle and mating system, therefore, have been considered to be representative for social systems in primate ancestors. Accepted models of social evolution in primates state that pair-bonding has evolved secondarily from diurnal group-living taxa and should therefore be constrained primarily to diurnal species. In contrast to these assumptions, the nocturnal fat-tailed dwarf lemur (Cheirogaleus medius) lives in permanent pairs, with obligate paternal care probably representing the evolutionary basis of pair-living. In this sociobiological field study, we analyzed the reproduction strategy of C. medius in the tropical forest of western Madagascar. In the rainy seasons from 1995 to 1999, 173 individuals of C. medius were captured and individually marked and 131 were genetically characterized through seven microsatellite loci. Additionally, 36 of these individuals were radio-tracked and observed. For 53 genotyped individuals, including 16 offspring, information about pair-bonding and family structure was known from field observations. Genetic analyses revealed that yearlings and infants living with an adult pair were in all cases sibs of the social mother. However, C. medius does not restrain from extra-pair copulations (EPCs) and a high rate of extra-pair paternity (44%) was detected. Males sired offspring with their female partners as well as with extra-pair females within the same year, indicating that males may increase their reproductive success by EPCs without necessarily running the risk of cuckoldry. Females on the other hand do not seem to run the risk of reduced paternal care, either because males cannot detect relatedness of young, or because they might even increase their inclusive fitness by raising offspring of closely related males. Since females reproduce preferentially with territory holders and no paternity could be assigned to floating males, superior genetic quality of the males might be crucial for female choice. Received: 12 January 2000 / Revised: 15 August 2000 / Accepted: 26 August 2000     

Effects of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the swimming behavior,population growth and reproduction of the rotifer Brachionus plicatilis

Polybrominated diphenyl ethers(PBDEs) are new kinds of persistent organic pollutants(POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE(BDE-47)and deca-BDE(BDE-209) were applied, and their toxic effects on the swimming behavior,population growth and reproduction of Brachionus plicatilis were investigated. The results showed that:(1) The actual concentrations of BDE-47 and-209 in the seawater phase measured by GC–MS(Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations.(2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 is more toxic than BDE-209.(3) Both BDE-47 and-209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females(OF/NOF), the ratio of mictic females/amictic females(MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and-209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.     

Effects of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the swimming behavior, population growth and reproduction of the rotifer Brachionus plicatilis

Polybrominated diphenyl ethers (PBDEs) are new kinds of persistent organic pollutants (POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE (BDE-47) and deca-BDE (BDE-209) were applied, and their toxic effects on the swimming behavior, population growth and reproduction of Brachionus plicatilis were investigated. The results showed that: (1) The actual concentrations of BDE-47 and -209 in the seawater phase measured by GC-MS (Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations. (2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 ismore toxic than BDE-209. (3) Both BDE-47 and -209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females (OF/NOF), the ratio of mictic females/amictic females (MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and -209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.     

我国绿色产业投资机制建立与启动

本文针对当前我国绿色产业投资机制存在的诸多问题，从产权、市场、制度等方面剖析了绿色产业投资机制扭曲的内因，并在此基础提出了完善绿色产业投资机制的思路与对策     

治污投资方向选择的灰靶决策法

依据灰色决策的基本原理，结合治污投资方向选择的决策实际，采用灰靶决策法对治污投资方向进行优化决策，结果表明，灰靶决策法原理直观、计算简便、精确度高，是治污投资方向选择优化决策的一种有效方法。     

Strategies to overcome barriers to the development of sustainable agriculture in Canada: The role of agribusiness

Strategies to involve agribusiness in the development of sustainable agricultural systems have been limited by the lack of a comprehensive conceptual framework for identifying the most critical supportive policies, programs and regulations. In this paper, we propose an efficiency/substitution/redesign framework to categorize strategies for modifying agribusiness practices. This framework is then used to identify a diverse range of short, medium, and long-term strategies to be pursued by governments, community groups, academics and agribusiness to support the transition. Strategies discussed include corporate greening, ethical investment, changing the legal status of the corporaton, new business forms and the development of ecological economics.     

THEORY AND REALITY IN ALLOCATING FEDERAL RESOURCES TO WATER RESOURCES DEVELOPMENT1

ABSTRACT: Federal spending on water resource development projects exceeds $10 billion annually. This paper examines the economic theory and practice on which the Federal water resource development plans are based. Existing theoretical and applied problems result in overinvestment. These include 1) no standard of value for the tradeoff of environmental objectives with economic objectives; 2) benefits based on “willingness to pay,” but beneficiaries pay only a fraction of a project's costs; 3) beneficiaries “shop around” among program purposes in order to reduce their commitments; and 4) benefit/cost (B/C) analyses are based on a discount rate, which is consistently below the Federal borrowing rate. Furthermore, the Government Accounting Office (GAO) frequently finds that the agency regulations are inadequate and result in inconsistent and questionable benefit computations. The President has proposed a series of water policy reforms, to reduce some of the apparent overinvestment in water resource development, but fundmental corrective action rests with the members of Congress.     

AN APPLICATION OF OPERATIONS RESEARCH METHODS TO BEACH RENOURISHMENT PROJECTS1

ABSTRACT: Mathematical models have been widely used in business to minimize cost and maximize profit. In this paper such models are used to help determine the optimum strategy for a beach renourishment project including the initial and subsequent fill quantities and the length of a complete renourishment cycle. The importance of considering economic factors is emphasized, and the sensitivity of the optimal values to changes in the basic parameters of the models are discussed. The possible extensions and limitations of the models are considered.     

论我国环境保护投资与投资制度的概念

本文从对我国投资概念的理论入手，论述了我国环境保护投资与投资制度的概念和意义。     

Colony specificity of Dufour gland secretions in a functionally monogynous ant

Summary. Queens in colonies of the small myrmicine ant, Leptothorax gredleri Mayr 1855 (Hymenoptera, Formicidae) engage in dominance interactions and form social hierarchies, in which typically only the top-ranking queen lays eggs. Occasionally, queen antagonism escalates to violent mandible fighting, during which the sting is used to apply Dufour gland secretions onto the cuticle of the opponent. Contaminated queens often are attacked by nestmate workers. Here we show that the chemical composition of the Dufour gland is colony-specific and that workers can discriminate between secretions from their own and other colonies. Our findings suggest that Dufour gland secretions are involved in the establishment of hierarchies within a colony. When invading an alien colony the queen presumably employs the secretions during the expulsion of the resident queen. Apparently, Dufour gland secretions play a role in intraspecific queen competition similar to that in slave-making and inquiline formicoxenine ants, where they function as "propaganda substances" in an interspecific context. Received 7 July 1998; accepted 15 September 1998.