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Of major concern to agriculturists and society are issues of sustainability and land and resource requirements for food and fiber. Sustainability of Swedish domestic agriculture is explored using the production of tomatoes in greenhouses as a case study. Issues of sustainability are related to net yields, environmental loading, greenhouse gases, employment and land use. A model for evaluation of sustainability is developed and illustrated using the concepts and theories of
analysis. The intensive tomato production system investigated was shown to be highly dependent on non-renewable resources and human service fed back from society. Substituting wood powder from logging residues for the oil used for heating reduced the environmental load and improved the sustainability of the system significantly. 相似文献
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Mapping wetlands in the Lower Mekong Basin for wetland resource and conservation management using Landsat ETM images and field survey data 总被引:1,自引:0,他引:1
The Mekong River Basin is considered to be the second most species rich river basin in the world. The 795,000 km(2) catchment encompasses several ecoregions, incorporating biodiverse and productive wetland systems. Eighty percent of the rapidly expanding population of the Lower Mekong Basin (LMB), made up in part by Lao PDR, Thailand, Cambodia and Viet Nam, live in rural areas and are heavily reliant on wetland resources. As the populations of Cambodia and Lao PDR will double in the next 20 years, pressure on natural resources and particularly wetlands can only increase. For development planning, resource and conservation management to incorporate wetland issues, information on the distribution and character of Mekong wetlands is essential. The existing but outdated wetland maps were compiled from secondary landuse-landcover data, have limited coverage, poor thematic accuracy and no meta-data. Therefore the Mekong River Commission (MRC) undertook to produce new wetland coverage for the LMB. As resources, funding and regional capacity are limited, it was determined that the method applied should use existing facilities, be easily adaptable, and replicable locally. For the product to be useful it must be accepted by local governments and decision makers. The results must be of acceptable accuracy (>75%) and the methodology should be relatively understandable to non-experts. In the first stage of this exercise, field survey was conducted at five pilot sites covering a range of typical wetland habitats (MRC wetland classification) to supply data for a supervised classification of Landsat ETM images from the existing MRC archive. Images were analysed using ERDAS IMAGINE and applying Maximum Likelihood Classification. Field data were reserved to apply formal accuracy assessment to the final wetland habitat maps, with resulting accuracy ranging from 77 to 94%. The maps produced are now in use at a Provincial and National level in three countries for resource and conservation planning and management applications, including designation of a Ramsar wetland site of international importance. 相似文献
147.
Philopatry, male presence and grooming reciprocation among female primates: a comparative perspective 总被引:3,自引:0,他引:3
Competition for food and a safe location in a group are considered to be the main determinants of variation in social relationships
among female primates. The effect of the presence of males is usually overlooked, however. Here we put forward two hypotheses
connecting the (relative) number of males in a group, a statistic measuring the strength of positive relationships among females
(the degree of reciprocity of grooming) and female residence. Under the first hypothesis, we assumed that philopatric females
suffer especially from competition for males. Because females of these species are restrained to their native group and thus
do not move to groups where better conditions (i.e. more males) prevail, a higher socionomic sex ratio would imply reduced
competition and this should be reflected in better relationships among females (i.e. in a higher degree of reciprocation).
The second hypothesis is based on the contention of Wrangham (1987) that groups with more males are better able to defend
large food sources: in these groups female relationships would suffer less from within-group competition for food. We therefore
also expected a positive correlation between the absolute number of males and grooming reciprocation. To test the hypotheses,
matrices of grooming interactions were collected by going through the primatological literature. For ten female-resident and
four female-transfer primate species, the degree of grooming reciprocation was quantified using a specially adapted matrix
statistic. The results favoured the first (competition for males) hypothesis. The degree of grooming reciprocation among females
was positively correlated with socionomic sex ratio, but neither with group size nor with the absolute number of males. Correlations
between the degree of reciprocity and sex ratio were confirmed at three levels: within the same group at different points
in time, between groups of the same species, and between species. In addition, the degree of reciprocation increased with
sex ratio more strongly in typical single/variable male than in multi-male species. This we interpreted as a direct consequence
of the lower social availability of males for females in multi-male groups than single-male groups. In turn, this effect may
be due to males competing for females in multi-male groups.
Received: 28 May 1997 / Accepted after revision: 9 November 1997 相似文献
148.
Stefan Banzhaf Marko Filipovic Jeffrey Lewis Charlotte J. Sparrenbom Roland Barthel 《Ambio》2017,46(3):335-346
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are found in aquatic systems, flora, and fauna worldwide. These potentially harmful compounds are also frequently detected in Sweden and have already resulted in severe problems for public drinking water supply, i.e., some wells had to be closed due to high PFAS concentrations both in raw water and produced drinking water. Knowledge on PFAS occurrence in Sweden is still quite low, although monitoring is currently ongoing. This work describes potential sources for PFASs to enter the drinking water supply in Sweden and compares different occurrences of PFASs in raw and drinking water in the country. Moreover, the monitoring history, the legal situation, and remediation actions taken are presented. Finally, future challenges and the way forward in Sweden are discussed. 相似文献
149.
Efficacy of insurance for organisational disaster recovery: case study of the 2010 and 2011 Canterbury earthquakes
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Insurance is widely acknowledged to be an important component of an organisation's disaster preparedness and resilience. Yet, little analysis exists of how well current commercial insurance policies and practices support organisational recovery in the wake of a major disaster. This exploratory qualitative research, supported by some quantitative survey data, evaluated the efficacy of commercial insurance following the sequence of earthquakes in Canterbury, New Zealand, in 2010 and 2011. The study found that, generally, the commercial insurance sector performed adequately, given the complexity of the events. However, there are a number of ways in which insurers could improve their operations to increase the efficacy of commercial insurance cover and to assist organisational recovery following a disaster. The most notable of these are: (i) better wording of policies; (ii) the availability of sector‐specific policies; (iii) the enhancement of claims assessment systems; and (iv) risk‐based policy pricing to incentivise risk reduction measures. 相似文献
150.
Bergkvist C Aune M Nilsson I Sandanger TM Hamadani JD Tofail F Oyvind-Odland J Kabir I Vahter M 《Chemosphere》2012,88(7):784-790
In low-income countries, the use of some organochlorine pesticides is still common in order to increase food production. Monitoring the chemical exposure is an important step in risk-reducing strategies. This is the first study to report concentrations of organochlorines in breast milk of women from Bangladesh where farming is the main income source.Organochlorines such as p,p′-DDT, o,p′-DDT, p,p′-DDE, p,p′-DDD (i.e., ∑DDT), HCB, α-, β- and γ-HCH, trans-chlordane, cis-chlordane, oxy-chlordane, trans-nonachlor, cis-nonachlor, mirex and polychlorinated biphenyls (CB 28, 52, 99, 101, 105, 114, 118, 123, 128, 138, 141, 149, 153, 156, 157, 163, 167, 170, 180, 183, 187, 189, 194) were analyzed in breast milk collected in 2002 from 72 first-time mothers (median age 20 years) living in the rural area Matlab, Bangladesh.While the concentrations of PCBs and many of the pesticides were low, the concentrations of p,p′-DDT and its metabolite p,p′-DDE were high (median 349 and 1645 ng g−1 lipid, respectively) in comparison to other countries. The median value of ∑DDT was 2123 ng g−1 lipid. The estimated daily exposure to p,p′-DDT, p,p′-DDE and ∑DDTs was 10, 30 and 42 μg kg−1 body weight, respectively, in 3 months old infants. The p,p′-DDE/p,p′-DDT ratio ranged from 1 to 23, where 58% of the mothers had a ratio below 5 indicating recent or ongoing DDT exposure.This study reports infant exposure and maternal body burden of organochlorines through breast milk. Although the findings give no reason to limit breast-feeding, it is essential to identify the main exposure sources and find means to decrease the exposure. 相似文献