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121.
A dynamic dose and risk assessment model is developed to estimate radiological consequences of atmospheric emissions from nuclear power plants. Internal exposure via inhalation and ingestion, external exposure from clouds and radioactivity deposited on the ground are included in the model. The model allows to simulate interregional moves of people and multi-location food supply in the computational domain. Any long-range atmospheric dispersion model which yields radionuclide concentrations in air and on the ground at predetermined time intervals can easily be integrated into the model. The software developed is validated against radionuclide concentrations measured in different environmental media and dose values estimated after the Chernobyl accident. Results obtained using the model compare well with dose estimates and activities measured in foodstuffs and feedstuffs. 相似文献
122.
Energy efficiency and conservation for individual Americans 总被引:1,自引:0,他引:1
D. Pimentel Jennifer Gardner Adam Bonnifield Ximena Garcia Julie Grufferman Claire Horan Julia Schlenker Emily Walling Emily Rochon 《Environment, Development and Sustainability》2009,11(3):523-546
Americans make up only 4% of the world population, yet currently consume 25% of the world’s fossil fuels. The U.S. imports
63% of its oil and it is predicted that by 2020 the U.S. will be importing 95% of its oil resources. Over the past century,
ample and affordable supplies of fossil fuels have powered the growth and prosperity of the economies of the US and other
countries. Within this century, world oil supplies will decline while demand is projected to continue to increase, suggesting
that we will have to transition to different fuels or become much more energy efficient or both. Looking ahead to the near
decades, estimates are that consumers will have to reduce their energy use by at least 50%. This reduction will be necessary
in large part due the decline in the availability of conventional oil and gas, but also because the U.S. population will continue
to grow in number. Although government action is important, individuals too often discount their ability to make significant
contributions to solving such major problems. This investigation identifies how informed and concerned individuals can collectively
conserve fossil energy.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.
An erratum to this article can be found at 相似文献
123.
High-quality food and general good health are fundamental needs that have to be satisfied if society is to attain a high standard of living. Accordingly, a great deal of effort is expended in order to guarantee a high quality of food and ensure healthy living conditions. Among other things, these efforts entail massive substance flows. Significant substance flows are connected with the production and consumption of food and can be regarded from an economic, social, or environmental point of view. Substance flows are a part of both nature and the anthroposphere. This study demonstrates that food production at present is not linked to societal issues of production and sustainability; rather, it shows that a systematic approach and an analysis of issues and measures to be taken are required. This interconnectedness can be described as a timescape, in analogy to a landscape. For proper orientation in a landscape, a map is helpful, especially in combination with a compass. In the same way, we need a temporal orientation. Time scales serve as a compass to give orientation. A complete temporal analysis that includes all relevant temporalities provides the information that is encoded in a map. What has to be learned and exercised is the reading of such temporal maps. One method of doing this is temporal impact analysis (TIA). Temporal impact analysis brings issues that are not normally focused on into the foreground. It allows a better understanding of the implications of certain substance flows and the measures necessary for their management, and it provides an opportunity to develop a more sustainable management of substance flows. 相似文献
124.
Tsegaye Tadesse Menghestab Haile Gabriel Senay Brian D. Wardlow Cody L. Knutson 《Natural resources forum》2008,32(4):265-279
Reducing the impact of drought and famine remains a challenge in sub‐Saharan Africa despite ongoing drought relief assistance in recent decades. This is because drought and famine are primarily addressed through a crisis management approach when a disaster occurs, rather than stressing preparedness and risk management. Moreover, drought planning and food security efforts have been hampered by a lack of integrated drought monitoring tools, inadequate early warning systems (EWS), and insufficient information flow within and between levels of government in many sub‐Saharan countries. The integration of existing drought monitoring tools for sub‐Saharan Africa is essential for improving food security systems to reduce the impacts of drought and famine on society in this region. A proactive approach emphasizing integration requires the collective use of multiple tools, which can be used to detect trends in food availability and provide early indicators at local, national, and regional scales on the likely occurrence of food crises. In addition, improving the ability to monitor and disseminate critical drought‐related information using available modern technologies (e.g., satellites, computers, and modern communication techniques) may help trigger timely and appropriate preventive responses and, ultimately, contribute to food security and sustainable development in sub‐Saharan Africa. 相似文献
125.
From subsistence farming towards a multifunctional agriculture: sustainability in the Chinese rural reality 总被引:1,自引:0,他引:1
Prändl-Zika V 《Journal of environmental management》2008,87(2):236-248
The rural economic situation in China-with a living standard mostly at subsistence level-lags far behind the prosperous development in the cities and coastal areas. To balance this disequilibrium, comprehensive concepts and endeavors are necessary keeping in view all-not just economic-interests and needs that contribute to lively rural identities. In this context the role of agriculture, where still 50% of the Chinese population are working, will be newly defined, and sustainability concepts can help to find a readjusted position within the Chinese economy focusing on environmental health and food safety as main targets of political and other supporting measures. Within the SUCCESS project, a Concept of Sustainable Agriculture was developed and it drafts one conceivable relation between the exposure to natural resources and economy and tries to find new answers to the broad range of rural challenges in China. It is a qualitative model and, therefore, not always fully applicable, but in the concrete situation of villages, it shows possible directions of sustainability-oriented development by considering the typical local potentials. In the Chinese context that means identifying the different functions of agriculture-the well-known and the hidden-to make them explicit for the Chinese public and therewith to give them new significance. The article is based on a 3-years study within the EU-China Project SUCCESS with field research in four Chinese rural communities. It analyzes the agricultural sustainability potential of these selected villages against the background of massive structural changes within the next 20 years in rural China. Starting from the current agricultural reality, based on a qualitative analysis of the actual situation, local potentials and needs towards sustainable production and marketing are identified, and possible functions of the Chinese agriculture are formulated for the future. 相似文献
126.
A study was conducted in southern Ethiopia to evaluate the nutrient status on smallholder farms with respect to land use class
(garden, grassland, and outfield) and slope position (upper, middle, and lower). Soil physical and chemical properties were
quantified using soil samples collected at two depths (0–15 and 15–30 cm). Available phosphorous was significantly different
among the three land use classes. However, organic carbon and total nitrogen were lower in the outfield compared to the garden
and grass land but not significantly different. The lower than expected nutrient status of the garden and grassland, which
receive almost all available organic supplements, was attributed to the overall low availability of these inputs. Similarly,
pH and cation exchange capacity were not significantly different among the different land use classes. However, the sum of
the exchangeable cations was significantly higher in the garden compared to the outfields. Comparison at landscape level revealed
that the sand fraction was significantly greater, whereas the silt fractions were significantly smaller, on the lower slopes
relative to the middle slopes. Moreover, the organic carbon, total nitrogen, cation exchange capacity, Ca, and Mg values were
significantly less on lower slopes than upper and middle slopes. Perhaps this is because of leaching and the effect of deposition
of coarser sediments from the prevailing gully system. Overall, the fertility of the soil was adequate for supporting smallholder
farming, but consideration must be given to reducing pressure on the land resources, addressing erosion problems, and providing
a line of credit for purchasing inputs. 相似文献
127.
128.
The Komati Downstream Development Project (KDDP), based upon the Maguga Dam has enabled 6,000 hectares of semi‐arid lowveld, in a region with low and highly variable rainfall to be converted from subsistence to irrigated commercial farming, mainly of sugar cane. This has transformed the Swazi sugar industry from one dominated by a small number of large‐scale commercial estates to one where more than 1,500 previously impoverished small‐scale Swazi farmers have been able to enter the industry by joining farmers’ associations and creating communally managed farms. Recent changes to the EU's Sugar Protocol have undermined the financial viability of the KDDP farms and undermined food security, especially for the poorest, due to the cut in sugar prices. However, some farmers’ associations have opted to keep some of their land as irrigated home gardens, rather than convert all their land to sugar cane. This model has improved food security at a time of low sugar prices and points to a more sustainable way of using water from large scale dams than the conventional model. It is argued that the EU should target support to members of the KDDP who have taken out large‐scale loans to pay for the in‐field infrastructure and encourage all farmers’ associations to adopt the food garden model. This would enable them to continue to benefit from the irrigation through improved production of subsistence crops, whilst they diversify their commercial production into novel markets. 相似文献
129.
We investigated the extent of Sb uptake by maize (Zea mays) and sunflower (Helianthus annuus) from nutrient solutions containing concentrations from 3 to 24 mg/L of potassium antimonate, with the aim of determining
the potential of Sb to enter the food chain. The maximum shoot Sb concentrations in Z. mays and H. annuus were 41 mg/kg and 77 mg/kg dry weight, respectively. There was no significant difference in Sb uptake between species. The
average bioaccumulation coefficients (the plant/solution concentration quotients) were 1.02 and 1.93 for Z. mays and H. annuus, respectively. Phosphate addition did not affect plant growth or Sb uptake. Antimony uptake by both Z. mays and H. annuus is unlikely to pose a health risk to animals and humans. 相似文献
130.
Tae Won Kim Kotaro Sakamoto Yasuhisa Henmi Jae C. Choe 《Behavioral ecology and sociobiology》2008,62(7):1139-1147
For males, courting and foraging are often behavioral alternatives, which take time and consume energy. When males have a
possibility of mating with receptive females, there may be a behavioral trade-off between courtship and feeding; the outcome
of which may be affected by male physiological condition and food availability. Although many mathematical models and empirical
studies suggest that the expression of male courtship signals are condition-dependent, decisions about courtship and mating
strategies in relation to food availability have not attracted much attention. In this study, we tested whether daily changes
in food availability affect males’ decisions about whether to court. We conducted experiments with the fiddler crab Uca lactea by providing males with additional food every other day. In food-supplemented enclosures, males did not increase courtship
activity on the days when food was supplemented. However, they built more courtship structures (semidomes) and waved more
on the days when they were not given additional food. Male size had a strong influence on the number of days the males courted.
We also tested whether the frequency of surface mating, as an alternative reproductive tactic, decreased when food was supplemented.
Contrary to our expectation, the number of males that exhibited the surface-mating tactic increased when food was supplemented
whereas the number of mate-searching females did not change. Our findings in this field study suggest that reproductive decisions
by male fiddler crabs are affected by fluctuating food availability and present body condition, and the alternative mating
tactic of this species may be more frequently used by males under good condition. 相似文献