Food and drink consumption was found to be responsible for around 20–30% of environmental impacts. Environmental impacts occur during all stages of the food production chain. However, households influence these impacts with through their choice of diet and habits, thus directly affecting the environment through food-related energy consumption and waste generation. With the multiplication of local policies for sustainable consumption, it has become increasingly useful to gather information on the evolution of the ecological impacts associated with household food consumption. Dealing with the indicators of household consumption of fruits and vegetables will enable changes in the population's lifestyles and the effectiveness of local policies to be monitored.The aims of this article are twofold: to provide a conceptual framework on the purposes of ecological indicators of fruit and vegetable consumption (EIFVCs) and to provide a methodological approach for selecting and measuring the most relevant EIFVCs at a local scale. Considering the great diversity of ecological impacts, the large number of potential EIFVCs must be reduced to obtain fewer EIFVCs, but that are relevant at local scale. To be relevant, the EIFVCs must provide information on the three phases of consumption (acquisition, use, and disposal) and on the upstream and downstream phases of the consumption process; they should evaluate the more problematic ecological impacts at the local scale (level of concern); and they have to only point out the ecological impacts that households can significantly reduce through their consumption rates. To measure relevant EIFVCs, three approaches must be combined: monitoring the ecological impacts, measuring the material and energy fluxes associated with household consumption, and analysing the consumer behaviours that result in the observed ecological impacts.As an illustration, the methodology is applied to the Bordeaux Metropolitan Area (France). In this area, eleven EIFVCs seem relevant. The use of surveys characterises all eleven of the EIFVCs, despite the difficulty of establishing quantified relationships between household behaviours and measured ecological impacts. The measuring of fluxes is possible for eight of them, whereas the monitoring of ecological impacts is only feasible for two of them. 相似文献
A simple and accurate model of high-temperature treatment of wood can assist in the process design and the evaluation of performance of equipment. The high-temperature treatment of wood is essentially a drying process under linearly-increased gas temperature up to final temperature of 220-230 °C which is a challenging process to model. This study is aimed to assess the applicability and accuracy of the reaction engineering approach (REA) to model the heat treatment of wood. In order to describe the process using the REA, the maximum activation energy (ΔEv,b) is evaluated according to the corresponding external conditions during the heat treatment. Results indicate that the REA coupled with the heat balance describes both moisture content and temperature profiles during the heat treatment very well. A good agreement towards the experimental data is indicated. It has also been shown that the current model is highly comparable in accuracy with the complex models. 相似文献
The molecular origin of nucleotide insertion catalysis and fidelity of DNA polymerases is explored by means of computational simulations. Special attention is paid to the examination of the validity of proposals that invoke prechemistry effects, checkpoints concepts, and dynamical effects. The simulations reproduce the observed fidelity in Pol β, starting with the relevant observed X-ray structures of the complex with the right (R) and wrong (W) nucleotides. The generation of free energy surfaces for the R and W systems also allowed us to analyze different proposals about the origin of the fidelity and to reach several important conclusions. It is found that the potential of mean force (PMF) obtained by proper sampling does not support QM/MM-based proposals of a large barrier before the prechemistry state. Furthermore, examination of dynamical proposals by the renormalization approach indicates that the motions from open to close configurations do not contribute to catalysis or fidelity. Finally we discuss and analyze the induced fit concept and show that, despite its importance, it does not explain fidelity. That is, the fidelity is apparently due to the change in the preorganization of the chemical site, as a result of the relaxation of the binding site upon binding of the incorrect nucleotide. Finally and importantly, since the issue is the barrier associated with the enzyme-substrate (ES)/DNA complex at the chemical transition state and not the path to this complex formation (unless this path involves rate determining steps), it is also not useful to invoke checkpoints while discussing fidelity. 相似文献
The World Health Organization (WHO) has a commitment to helping Member States achieve safe, sustainable and health-enhancing human environments, protected from biological, chemical and physical agents. The latter includes advising on the health impact of electromagnetic fields (EMFs) and radiation.
The results of the WHO/ICNIRP/NRPB workshop on static magnetic fields, published in this volume, provide a valuable and much needed contribution to the health risk assessment of exposure to static electric and magnetic fields, which is currently being coordinated by the WHO's International EMF Project. This WHO health risk assessment will be published as an environmental health criteria (EHC) monograph in early 2005.
This paper briefly gives an overview of the process of developing the WHO static fields EHC monograph, the criteria applied to studies that could contribute to the EHC, along with the ‘weight-of-evidence’ approach to health risk assessment. In addition, there is an increasing awareness of the need to account for uncertainty in the science database. This is traditionally addressed by further research, and the EMF project addresses these needs through the development of a ‘research agenda’. However, research programmes may take several years to complete, and the long latency associated with diseases such as cancer in people may also preclude a rapid outcome in some studies. The issue of current uncertainty is being addressed by the WHO EMF project through the development of a ‘precautionary framework’ in which precautionary measures will be applied to policy recommendations. 相似文献
Surveys were conducted in the cold desert environment of the Lahaul valley in the northwestern Himalaya for assessing the past and present status of Kuth (Saussurea lappa) cultivation. The findings reveal that this age-old practice now is in bottleneck. Main factors responsible for this setback to the species were the lengthy cultivation cycle, small land holdings, and even fluctuating and relatively low market prices. Owing to these constraints farmers have now started replacing cultivation of this threatened herb with pea (Pisum sativum L.), potato (Solanum tuberosum L.) and hop (Humulus lupulus L.). These crops obtained popularity due to comparatively more economic returns as well as their easy adaptability to the short growth season of the cold desert environment. Kuth cultivation in this region is among the interesting examples of domesticating wild medicinal herb by some innovative farmers during the 1920s. However, in the recent past farmers have been less interested to continue this practice due to its larger cultivation cycle, more profits with cash crops like pea and potato, and permit formalities at the time of export from the valley. In addition to being the oldest cash crop in the cold desert environment, Kuth is an endangered medicinal herb that has to be conserved on a priority basis. This study attempts to find out potential measures such as regular revision of market rates, development of existing uncultivable land under medicinal plant cultivation and strengthening the marketing network through establishment of federations of farmers at village level to revive cultivation of this important species. 相似文献