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41.
A honey bee (Apis mellifera) queen mates with about ten haploid drones, thus producing colonies composed of about ten subfamilies of super-sisters. An increasing but controversial body of literature supports the views that: (1) Members of each subfamily within a colony can recognise each other, and distinguish supersisters from half-sisters. (2) Members of each subfamily use this recognition information and increase the reproductive fitness of their own subfamily at the expense of half-sisters through behaviour termed nepotism. A mathematical model is developed that shows that task specialisation by subfamilies, and bees that repeatedly undertake the behaviour within subfamilies, can influence the numbers of interactions among super-sisters, relative to the numbers of interactions between half-sisters. The model is then evaluated using a data set pertaining to trophallaxis behaviour in a two-subfamily colony. It is concluded that with this data set, task specialisation and subfamily recognition were indeed confounded, suggesting that the apparent subfamily recognition could easily have been an artefact of task specialisation. Correspondence to: B.P. Oldroyd  相似文献   
42.
Summary Male sand lizards (Lacerta agilis) are polygynous and guard individual females for several hours to days after copulation. Even though the copulation itself only lasts 2–4 min, the total time that a male invests per female is considerably more and may constitute a substantial investment during a mating season. In such situations, when male copulation frequency is constrained, or when variation in female fecundity is high, mate choice by males may be adaptive. Large body size in female sand lizards is correlated with higher fecundity. In choice experiments performed in the laboratory, male sand lizards preferred to court large females rather than small females. In addition, when there was little difference in size between the females in the experiment, the males visited the two females more often before they started to court the preferred female. The results from a field study during 1984 and 1987–1990 showed that females are non-aggressive, have small neighboring home ranges (c. 100 m2) and may share burrows and sites for thermoregulation. This means that females can be found close together and thus gives males the opportunity to choose a mate. Assortative mating with respect to size was observed in a natural population, as well as a limited number of direct choices of females by males. These results support the results of the choice experiment.  相似文献   
43.
To reduce greenhouse gas (GHG) emissions and help mitigate climate change, urban water systems need to be adapted so that electrical energy use is minimised. In this study, energy data from 2011 was used to quantify energy use in China’s urban water supply sector. The objective was to calculate the energy co-benefits of urban water conservation policies and compare energy use between China and other countries. The study investigated influencing factors with the aim of informing the development of energy efficient urban water infrastructure. The average energy use per cubic metre and per capita for urban water supply in China in 2011 was 0.29 kWh/m3 and 33.2 kWh/cap year, respectively. Total GHG emissions associated with energy use in the urban water supply sector were 7.63 MtCO2e, or carbon dioxide equivalent. Calculations using these indicators showed significant energy savings could result from water conservation measures. A comparison between provinces of China showed a direct correlation between energy intensity of urban water supply and the population served per unit length of pipe. This may imply energy and emission intensity can be reduced if more densely populated areas are supplied by a corresponding pipe density, rather than by a low-density network operating at higher flow rates. This study also found that while the percentage of electrical energy used for urban water supply tended to increase with the percentage of population served, this increase was slower where water supply was more energy efficient and where a larger percentage of population was already supplied.  相似文献   
44.
Planetary Stewardship in an Urbanizing World: Beyond City Limits   总被引:1,自引:0,他引:1  
Cities are rapidly increasing in importance as a major factor shaping the Earth system, and therefore, must take corresponding responsibility. With currently over half the world’s population, cities are supported by resources originating from primarily rural regions often located around the world far distant from the urban loci of use. The sustainability of a city can no longer be considered in isolation from the sustainability of human and natural resources it uses from proximal or distant regions, or the combined resource use and impacts of cities globally. The world’s multiple and complex environmental and social challenges require interconnected solutions and coordinated governance approaches to planetary stewardship. We suggest that a key component of planetary stewardship is a global system of cities that develop sustainable processes and policies in concert with its non-urban areas. The potential for cities to cooperate as a system and with rural connectivity could increase their capacity to effect change and foster stewardship at the planetary scale and also increase their resource security.  相似文献   
45.
46.
The REDD+ scheme of the United Nations intends to offer developing countries financial incentives to reduce the rates of deforestation and forest degradation for reducing global CO2 emissions. This is combined with building carbon stocks in existing wooded ecosystems and fostering other soil, biodiversity and water conservation objectives. Successful application of REDD+ to the Xylophone Triangle of West Africa faces substantial challenges and risks to both meeting REDD+ objectives and to the local people’s rights and livelihoods. The transnationality of the culturally coherent area requires collaboration of three national governments. The opportunities, however, are great to capitalize on the region’s biodiversity, the well-developed traditional ecological knowledge and the use of local medicinal plants as an integral part of the agro-ecosystem. Possibilities open to, not only sequester carbon, but also to increase the resilience of the ecosystem and of independent rural livelihoods in the face of climate change and globalization.  相似文献   
47.
The simultaneous adsorption of copper (Cu), cadmium (Cd), nickel (Ni), and lead (Pb) ions from spiked deionized water and spiked leachate onto natural materials (peat A and B), by-product or waste materials (carbon-containing ash, paper pellets, pine bark, and semi-coke), and synthetic materials (based on urea-formaldehyde resins, called blue and red adsorbents) or mixtures thereof was investigated. The adsorbents that gave the highest metal removal efficiencies were peat A, a mixture of peat B and carbon-containing ash, and a mixture of peat A and blue. At an initial concentration of 5 mg/l for each metal, the removal of each species of metal ion from spiked water and spiked leachate solutions was very good (>90%) and good (>75%), respectively. When the initial concentration of each metal in the solutions was twenty times higher (100 mg/l), there was a noticeable decrease in the removal efficiency of Cu2+, Cd2+, and Ni2+, but not of Pb2+. Langmuir monolayer adsorption capacities, qm, on peat A were found to be 0.57, 0.37, and 0.36 mmol/g for Pb2+, Cd2+, and Ni2+, respectively. The order of metal adsorption capacity on peat A was the same in the case of competitive multimetal adsorption conditions as it was for single-element adsorption, namely Pb2+ > Cd2+ ≥ Ni2+. The results show that peat alone (an inexpensive adsorbent) is a good adsorbent for heavy metal ions.  相似文献   
48.
Structuring sustainability science   总被引:2,自引:2,他引:0  
It is urgent in science and society to address climate change and other sustainability challenges such as biodiversity loss, deforestation, depletion of marine fish stocks, global ill-health, land degradation, land use change and water scarcity. Sustainability science (SS) is an attempt to bridge the natural and social sciences for seeking creative solutions to these complex challenges. In this article, we propose a research agenda that advances the methodological and theoretical understanding of what SS can be, how it can be pursued and what it can contribute. The key focus is on knowledge structuring. For that purpose, we designed a generic research platform organised as a three-dimensional matrix comprising three components: core themes (scientific understanding, sustainability goals, sustainability pathways); cross-cutting critical and problem-solving approaches; and any combination of the sustainability challenges above. As an example, we insert four sustainability challenges into the matrix (biodiversity loss, climate change, land use changes, water scarcity). Based on the matrix with the four challenges, we discuss three issues for advancing theory and methodology in SS: how new synergies across natural and social sciences can be created; how integrated theories for understanding and responding to complex sustainability issues can be developed; and how theories and concepts in economics, gender studies, geography, political science and sociology can be applied in SS. The generic research platform serves to structure and create new knowledge in SS and is a tool for exploring any set of sustainability challenges. The combined critical and problem-solving approach is essential.  相似文献   
49.
A study was performed between June 2001 and December 2004 with the primary objective of assessing long-term leaching from municipal solid waste incineration bottom ash in a test road construction in relation to a reference road made up of conventional materials and the natural geochemical conditions in the surroundings. The metal leaching from the test road and the reference road was compared with the natural weathering in the regional surroundings for three time scales: 16, 80 and 1000 years. The results show that Cu and Zn cause a geochemical anomaly from the test road compared with the surroundings. The leaching of Cu from the test road is initially high but will decline with time and will in the long term be exceeded by natural weathering. Zn on the other hand has low initial leaching, which will increase with time and will in the long term exceed that of the test road and the surroundings by a factor of 100-300. For the other metals studied, Al, Na, K and Mg, there is only very limited leaching over time and the potential accumulation will not exceed the background values in a 1000 years.  相似文献   
50.
This paper analyses proposals for new multi-level governance of Swedish water resources to implement the EU Water Framework Directive. The question is, do they satisfy the criteria for ecologically rational and democratically legitimate governance? The core of the analysis concerns an administrative 'trilemma' encountered in designing ecologically effective and democratically acceptable multi-level governance. This trilemma is characterised by tensions between effectiveness, participation and legitimacy, all core values of 'good governance'. The Swedish proposal constitutes an effort to achieve cost-effective implementation of the EU Directive through an ecosystem-based multi-level organisation. It also seeks to bring about democratically legitimate governance through stakeholder networks and negotiations at the sub-catchment level, and governance 'partnerships' among local governments and organised interests. In particular, the assessment addresses issues of integrating such 'super-local' and local alternatives within the larger web of multi-level water resource governance. Although intended to escape the 'trilemma', the proposed combination of formal government and informal governance is found wanting in terms of effectiveness as well as participation and legitimacy.  相似文献   
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