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31.
This study examines the impact of the creation of marine protected areas (MPAs), from both economic and biological perspectives. In particular, we examine the effects of protected patches and harvesting on resource populations. We conclude that protected patches are an effective means of conserving resource populations, even though extinction cannot be prevented in all cases. We discuss the dynamic optimization of a harvest policy by choosing E(t), the harvesting effort, as the dynamic variable. We also discuss the optimal equilibrium harvest policy and explain the biological and bioeconomic interpretations of the results. 相似文献
32.
Poverty studies have demonstrated that a group’s ability to escape poverty is largely dependent on the types of assets that the group’s members possess. A major claim that has been asserted with limited empirical evidence in the asset literature is the gender disparity dichotomy. Using rural Ghana as a case study, we assess the asset levels of farm households from a gender perspective. In doing so, we theorized and empirically tested assets on case bases. A household questionnaire survey was used to collect data from two hundred households in the Fanteakwa district of eastern Ghana. An asset index was used to compute the asset levels, while Kruskal–Wallis statistics was employed to compare the significance of the temporal changes. The results show a minimum level of asset endowment. Natural, social and financial assets were the three most endowed assets, with physical and human assets being the least. A gender analysis shows no significant difference, even though the levels of assets for the female-headed households were slightly higher than those of the male-headed households. However, the study found a 22.7% increment in the accumulation of financial assets among the female-headed households over the last 5 years compared to a 9.3% decrement in the same assets for their male-headed counterparts. Applying our theory, the results present an unbalanced and unstable asset situation among the household heads. We call for improvement, in physical and human assets. The overall study results imply an improvement in gender-asset accessibility in the context of rural Ghana. 相似文献
33.
Questioning Community Based Coral Reef Management Systems: Case Study of Awig-Awig in Gili Indah, Indonesia 总被引:1,自引:0,他引:1
Arif Satria Yoshiaki Matsuda Masaaki Sano 《Environment, Development and Sustainability》2006,8(1):99-118
Issues and complexities arising when the fisheries and marine tourism sectors have stakes in an institution governing the
coral reefs ecosystem called awig-awig are discussed, awig-awig is a colloquialism meaning ‘a local rule’. The community-based management system is commonly recognized as a better approach
to governing resources, however, the success of awig-awig in the study area is questionable. Awig-awig fails to deal with the conflict of interest among stakeholders in coastal resource appropriation, despite the community being
relatively culturally homogenous. The benefits of awig-awig are biased in favor of the tourism as opposed to fisheries, leading to the fishers’ resistance of awig-awig. There are critical factors to this weakness: a crisis of legitimacy within community, socio-economic inequality among actors
involved in such system, high intervention from external agencies, and the institutional conflict over conservation policy.
In addition, awig-awig reduces community spirit as it is perceived as not being attached to any customary law or traditional norms. Group cohesion
is challenged and there is no common understanding of the problem or alternatives strategies. 相似文献
34.
Increasing centralization of the control of fisheries combined with increased knowledge of food-web relationships is likely to lead to attempts to maximize economic yield from entire food webs. With the exception of predator-prey systems, we lack any analysis of the nature of such yield-maximizing strategies. We use simple food-web models to investigate the nature of yield- or profit-maximizing exploitation of communities including two types of three-species food webs and a variety of six-species systems with as many as five trophic levels. These models show that, for most webs, relatively few species are harvested at equilibrium and that a significant fraction of the species is lost from the web. These extinctions occur for two reasons: (1) indirect effects due to harvesting of species that had positive effects on the extinct species, and (2) intentional eradication of species that are not themselves valuable, but have negative effects on more valuable species. In most cases, the yield-maximizing harvest involves taking only species from one trophic level. In no case was an unharvested top predator part of the yield-maximizing strategy. Analyses reveal that the existence of direct density dependence in consumers has a large effect on the nature of the optimal harvest policy, typically resulting in harvest of a larger number of species. A constraint that all species must be retained in the system (a "constraint of biodiversity conservation") usually increases the number of species and trophic levels harvested at the yield-maximizing policy. The reduction in total yield caused by such a constraint is modest for most food webs but can be over 90% in some cases. Independent harvesting of species within the web can also cause extinctions but is less likely to do so. 相似文献
35.
Takafumi Fujita Takayuki Kawano Liwei Huang Yoshihiro Kojima Hitoki Matsuda Koichi Ushiroebisu 《Journal of Material Cycles and Waste Management》2007,9(1):15-20
To control the emission of halides into the environment, an experiment on the nonthermal plasma decomposition of the halides
CF4, CHF3, C2HCl3, and CHClF2 was conducted in a wire-in-tube corona reactor. It was found that the decomposition of C2HCl3 and CHClF2 was easy compared with the decomposition of CF4 and CHF3. With the addition of H2 in N2 gas, the decomposition ratio of CF4, C2HCl3, and CHClF2 increased. In contrast, the decomposition ratio of CHF3 in a hydrogen-rich atmosphere was lower than that in an N2 atmosphere. It was demonstrated that the yields of HF and/or HCl formed during halide decomposition clearly increased in
the presence of H2 in N2 gas. Furthermore, in order to prevent the production of unwanted products from halide decomposition, a combination of plasma
decomposition and in situ alkaline absorption was devised by coating a layer of Ca(OH)2 onto the surface of the grounding electrode. It was demonstrated that the Ca(OH)2 sorbent played an effective role as a scavenger, participating in halide decomposition by capturing reaction products such
as HCl and HF, therefore resulting in increased halide decomposition. 相似文献
36.
Naoto Mihara Dalibor Kuchar Yoshihiro Kojima Hitoki Matsuda 《Journal of Material Cycles and Waste Management》2007,9(1):21-26
From the point of view of a sustainable and environment-friendly society based on the recycling of material resources, it
is preferable to utilize waste gypsum as a substitute for lime, which is currently produced by the calcination of limestone.
In the present work, the reductive decomposition of CaSO4 was investigated under an atmosphere of CO: 2 vol%, CO2: 30 vol%, with N2 as a carrier gas without and with the addition of SiO2, Al2O3, or Fe2O3. It was found that the decomposition temperature of CaSO4 was significantly reduced from 1673 K to 1223 K when only 5 wt% Fe2O3 was added to CaSO4. In the case of the addition of SiO2 or Al2O3 to CaSO4, the decomposition temperature was reduced from 1673 K to 1623 K. This was due to the formation of composite oxides (calcium
ferrite, calcium silicate, or calcium aluminate) during the reaction of CaSO4 with the additives at a lower temperature. In addition, the formation of unfavorable product CaS was inhibited in the presence
of 5 wt% Fe2O3, and this inhibition effect further increased as the addition of Fe2O3 was increased. In contrast, no significant effect on the inhibition of CaS formation was observed on the addition of SiO2 or Al2O3. 相似文献
37.
Yoshiaki Tsuzuki Masato Fujii Yasuo Mochihar Kouki Matsu Minoru Yoneda 《环境科学学报(英文版)》2010,22(6):892-897
The first social experiment program in Japan to reduce domestic wastewater pollutant discharge by “soft interventions” in households
has been conducted in the Yamato-gawa River drainage area since 2005. The Yamato-gawa River has been listed as one of the worst
water quality rivers in Japan because of the larger annual average BOD. “Hard interventions” including deployment of wastewater
treatment facilities and artificial installation of natural purification facilities in the river has been conducted in these years to improve
river water quality. At the first Yamato-gawa River social experiment program (YR-SEP) in March 2005, BOD at the monitoring point
near the river mouth decreased about 6% during the Program. Natural purification e ect along the river was evaluated in this article
with one-dimensional water quality model for the six river sections. Larger biological oxygen consumption rate, kb, was estimated in
the sections with artificially installed natural purification facilities. The e ect of “soft interventions” in households in the YR-SEP was
estimated as 25% BOD decrease in the nearest monitoring point to the river mouth, when all the households participate in the Program
and BOD discharge reduction rate with “soft interventions” in households was 40%. 相似文献
38.
Yuki Yoshida Hirotaka Matsuda Kensuke Fukushi Shinya Ikeda Shunsuke Managi Kazuhiko Takeuchi 《Sustainability Science》2018,13(5):1399-1414
Present trends of urbanization are accompanied by increasing demographic and economic shrinkage of rural regions. In countries such as Japan, these rural regions trail behind metropolitan counterparts according to GDP, the conventional measure used to guide governmental policies. Yet, past research suggests that these regions may be undervalued. Further, the Inclusive Wealth Index (IWI), largely only used at the national level, may be able to capture aspects previously missed. As such, our study attempts to highlight the wealth of rural regions by comparing the inclusive wealth of Sado Island and Japan between 1990 and 2014. Minor methodological modifications were made according to data availability at the local level and to improve the accuracy of human capital estimations. Results captured the ongoing shrinkage of Sado and demonstrate the distinct potential of the IWI as a stock measure. Sado’s per capita wealth was about 10% lower than the national averages, but its natural capital was about threefold national averages. Supplementary estimations of the natural capital of fisheries and cultivated forests suggest that inclusion of additional factors in the evaluation would further increase the relative valuation of rural regions. We discuss implications of our estimations for wellbeing, and conclude with a critical appraisal of the IWI calculation towards policy implementation of the index. 相似文献
39.
Shizuka S. Shida Satoru Nemoto Rieko Matsuda 《Journal of environmental science and health. Part. B》2013,48(3):151-162
A sensitive and efficient method has been developed for the simultaneous determination of 73 multi-class acidic pesticides, such as phenoxy acid and sulfonylurea herbicides, in vegetables and fruits. The sample preparation procedure was carefully optimized for the efficient removal of co-extracted matrix components. The method involves extraction of acidic pesticides with acetonitrile containing hydrochloric acid, removal of water from crude extract by salting out, and sequential cleanup by octadecylsilyl silica gel and silica gel columns. For samples containing high amounts of pigments, such as spinach, additional cleanup using a graphitized carbon column was performed prior to liquid chromatography–mass spectrometry (LC–MS/MS) analysis. Recovery tests were performed for five times for each sample of cabbage, spinach, potato, eggplant, orange, and apple fortified at 0.01 mg kg?1. Out of the 73 tested pesticides, 70 for cabbage, 67 for spinach, 69 for potato, 67 for eggplant, 64 for orange, and 70 for apple were within the range of 70–120%, with relative standard deviations below 25%. Nitenpyram and pyrasulfotole showed low recoveries for all the samples tested, probably due to low recoveries from silica gel column. The developed method effectively removed co-extracted matrix components and was highly selective, with no interfering peaks found in the chromatograms of blank samples. The overall results indicate that the developed method is suitable for the quantitative analysis of acidic pesticide residues in vegetables and fruits. 相似文献
40.
Shin-ichi Sakai Junya Yano Yasuhiro Hirai Misuzu Asari Ritsuki Yanagawa Takeshi Matsuda Hideto Yoshida Tetsuji Yamada Natsuko Kajiwara Go Suzuki Tatsuya Kunisue Shin Takahashi Keijiro Tomoda Joachim Wuttke Paul Mählitz Vera Susanne Rotter Mario Grosso Thomas Fruergaard Astrup Julian Cleary Gil-Jong Oh Lili Liu Jinhui Li Hwong-wen Ma Ngo Kim Chi Stephen Moore 《Journal of Material Cycles and Waste Management》2017,19(4):1295-1313
Although the 2Rs (reduce and reuse) are considered high-priority approaches, there has not been enough quantitative research on effective 2R management. The purpose of this paper is to provide information obtained through the International Workshop in Kyoto, Japan, on 11–13 November 2015, which included invited experts and researchers in several countries who were in charge of 3R policies, and an additional review of 245 previous studies. It was found that, regarding policy development, the decoupling between environmental pressures and economy growth was recognized as an essential step towards a sustainable society. 3R and resource management policies, including waste prevention, will play a crucial role. Approaches using material/substance flow analyses have become sophisticated enough to describe the fate of resources and/or hazardous substances based on human activity and the environment, including the final sink. Life-cycle assessment has also been developed to evaluate waste prevention activities. Regarding target products for waste prevention, food loss is one of the waste fractions with the highest priority because its countermeasures have significant upstream and downstream effects. Persistent organic pollutants and hazardous compounds should also be taken into account in the situation where recycling activities are globally widespread for the promotion of a material-cycling society. 相似文献