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241.
Oleksiy Ivaschenko Jesse Doyle Jaekyun Kim Jonathan Sibley Zaineb Majoka 《Disasters》2020,44(3):455-476
This paper contributes to the evidence on the effectiveness of shock-responsive social protection systems in helping affected households recover from the negative consequences of disasters. It evaluates the influence of the top-up cash transfers provided by the Government of Fiji to poor households in the wake of Tropical Cyclone Winston, which struck the Pacific Island country on 20 February 2016. The impact evaluation strategy incorporates a sharp regression discontinuity design to define treatment and control groups, based on the eligibility threshold of the poverty benefit scheme. The results indicate that treatment households—that is, those that received cash transfers—are significantly more likely to report quicker recovery from various shocks. Female-headed households are more likely to recover from the ramifications, whereas households with older heads are less likely to do so. The presence of a functioning market appears to be a major factor aiding the speed of recovery. Finally, the evidence points towards strong district effects on recovery. 相似文献
242.
Jeane G. Francisco Rodrigo F. Pimpinato Valdemar L. Tornisielo Ana C. D. Guimarães 《Journal of environmental science and health. Part. B》2017,52(7):470-475
This study aimed to evaluate the sorption-desorption and leaching of aminocyclopyrachlor from three Brazilian soils. The sorption-desorption of 14C-aminocyclopyrachlor was evaluated using the batch method and leaching was assessed in glass columns. The Freundlich model showed an adequate fit for the sorption-desorption of aminocyclopyrachlor. The Freundlich sorption coefficient [Kf (sorption)] ranged from 0.37 to 1.34 µmol (1–1/n) L1/n kg?1 and showed a significant positive correlation with the clay content of the soil, while the Kf (desorption) ranged from 3.62 to 5.36 µmol (1–1/n) L1/n kg?1. The Kf (desorption) values were higher than their respective Kf (sorption), indicating that aminocyclopyrachlor sorption is reversible, and the fate of this herbicide in the environment can be affected by leaching. Aminocyclopyrachlor was detected at all depths (0?30 cm) in all the studied soils, where leaching was influenced by soil texture. The total herbicide leaching from the sandy clay and clay soils was <0.06%, whereas, ~3% leached from the loamy sand soil. The results suggest that aminocyclopyrachlor has a high potential of leaching, based on its low sorption and high desorption capacities. Therefore, this herbicide can easily contaminate underground water resources. 相似文献
243.
车用柴油机排气中的微粒是一种十分有害的大气污染物,如何有效地净化它一直是人们密切关注的课题。介绍了一种旋流分离净化技术,以及应用此技术首先应解决的问题。 相似文献
244.
目的预测乙丙橡胶在我国热带雨林环境下的库内储存寿命。方法通过定期检测乙丙橡胶在西双版纳试验站库内储存时自由状态下的力学性能和受力状态下的压缩永久变形,压缩永久变形在储存过程中表现出较为明显的变化趋势,以压缩永久变形作为乙丙橡胶热带雨林储存时的寿命预测指标较为合理。结果在储存过程中,乙丙橡胶材料的压缩永久变形与老化时间符合幂函数关系,通过对样品的压缩永久变形数据进行处理,获得乙丙橡胶的性能变化速率常数和老化试验常数,用二分法确定老化的特征常数,建立了乙丙橡胶在西双版纳环境库内储存受力状态下的老化寿命方程。结论通过回归效果检验,老化寿命方程具有显著的回归效果。误差分析表明,老化寿命方程具有较高的可信度,可以用来预测乙丙橡胶在西双版纳实际储存时的性能变化。 相似文献
245.
为了提高高炉干法除尘布袋的寿命,在重力除尘器和布袋除尘器之间加入旋风除尘装置,得到的旋风灰可以作为煤粉添加剂。对首秦高炉旋风灰进行粒度和化学成分分析,研究发现高炉旋风灰可以降低煤粉着火温度,提高燃烧效率,且其粒度分布与喷吹煤粉相似,可以作为高炉喷吹煤粉添加剂。通过实验室测定煤粉添加不同比例旋风灰后的燃烧率,确定在富氧率为3%,旋风灰添加比例为6%的条件下,可达到最佳的煤粉燃烧效果。旋风灰作为高炉自产的喷煤添加剂,与煤粉混合喷吹可以为企业减轻固废处理负担,同时带来可观的经济效益和社会效益。 相似文献
246.
247.
Uera RB Paz-Alberto AM Sigua GC 《Environmental science and pollution research international》2007,14(7):505-509
Background, Aims and Scope Research and development has its own benefits and inconveniences. One of the inconveniences is the generation of enormous
quantity of diverse toxic and hazardous wastes and its eventual contamination to soil and groundwater resources. Ethidium
bromide (EtBr) is one of the commonly used substances in molecular biology experiments. It is highly mutagenic and moderately
toxic substance used in DNA-staining during electrophoresis. Interest in phytoremediation as a method to solve chemical contamination
has been growing rapidly in recent years. The technology has been utilized to clean up soil and groundwater from heavy metals
and other toxic organic compounds in many countries like the United States, Russia, and most of European countries. Phytoremediation
requires somewhat limited resources and very useful in treating wide variety of environmental contaminants. This study aimed
to assess the potential of selected tropical plants as phytoremediators of EtBr.
Materials and Methods This study used tomato (Solanum lycopersicum), mustard (Brassica alba), vetivergrass (Vetiveria zizanioedes), cogongrass (Imperata cylindrica), carabaograss (Paspalum conjugatum), and talahib (Saccharum spontaneum) to remove EtBr from laboratory wastes. The six tropical plants were planted in individual plastic bags containing soil and
10% EtBr-stained agarose gel. The plants were allowed to establish and grow in soil for 30 days. Ethidium bromide content
of the test plants and the soil were analyzed before and after soil treatment. Ethidium bromide contents of the plants and
soils were analyzed using an UV VIS spectrophotometer.
Results Results showed a highly significant (p≤0.001) difference in the ability of the tropical plants to absorb EtBr from soils.
Mustard registered the highest absorption of EtBr (1.4±0.12 μg kg−1) followed by tomato and vetivergrass with average uptake of 1.0±0.23 and 0.7±0.17 μg kg−1 EtBr, respectively. Cogongrass, talahib, and carabaograss had the least amount of EtBr absorbed (0.2±0.6 μg kg−1). Ethidium bromide content of soil planted to mustard was reduced by 10.7%. This was followed by tomato with an average reduction
of 8.1%. Only 5.6% reduction was obtained from soils planted to vetivergrass. Soils planted to cogongrass, talahib, and carabaograss
had the least reduction of 1.52% from its initial EtBr content.
Discussion In this study, mustard, tomato, and vetivergrass have shown their ability to absorb EtBr from contaminated soil keeping them
from expanding their reach into the environment and preventing further contamination. Its downside, however, is that living
creatures including humans, fish, and birds, must be prevented from eating the plants that utilized these substances. Nonetheless,
it is still easier to isolate, cut down, and remove plants growing on the surface of the contaminated matrices, than to use
strong acids and permanganates to chemically neutralize a dangerous process that can further contaminate the environment and
pose additional risks to humans. Though this alternative method does not totally eliminate eventual environmental contamination,
it is by far produces extremely insignificant amount of by-products compared with the existing processes and technologies.
Conclusions Mustard had the highest potential as phytoremediator of EtBr in soil. However, the absorption capabilities of the other test
plants may also be considered in terms of period of maturity and productivity.
Recommendations and Perspectives It is recommended that a more detailed and complete investigation of the phytoremediation properties of the different plants
tested should be conducted in actual field experiments. Plants should be exposed until they reach maturity to establish their
maximum response to the toxicity and mutagenecity of EtBr and their maximum absorbing capabilities. Different plant parts
should be analyzed individually to determine the movement and translocation of EtBr from soil to the tissues of plants. Since
this study has established that some plants can thrive and dwell in EtBr-treated soil, an increased amount of EtBr application
should be explored in future studies. It is suggested therefore that a larger, more comprehensive exploration of phytoremediation
application in the management of toxic and hazardous wastes emanating from biotechnology research activities should be considered
especially on the use of vetivergrass, a very promising tropical perennial grass.
ESS-Submission Editor: Professor Zhihong Xu (zhihong.xu@griffith.edu.au: www.griffith.edu.au/centre/cfhr) 相似文献
248.
Joseph O. Lalah Bonface M. Muendo Zachary M. Getenga 《Journal of environmental science and health. Part. B》2013,48(7):690-696
The dissipation of hexazinone (Velpar) in two tropical soil types in Kenya was studied under field and semi-controlled conditions for a period of 84 days. The dissipation was found to be very rapid and this could be attributed to adverse weather conditions including high initial rainfall as well as to low soil-organic-matter content, volatilization, surface run-off and biodegradation. The DT50 values of dissipation obtained by first order kinetics were 20 days and 21.3 days in clay and loam soil types, respectively. The influence of bargasse compost (1000 μg/g dry soil) was also studied and was found to enhance dissipation to some extent, giving DT50 values of 18 days and 18.3 days in clay and loam soil types, respectively. 相似文献
249.
Understanding the circumstances and conditions surrounding disaster‐attributed deaths may contribute to designing and implementing emergency preparedness and response programmes. This paper introduces a three‐step cluster analysis of multiple binary variables to investigate mortality patterns related to tropical cyclones. It is designed to overcome the difficulties of performing cluster analysis in a disaster database that is composed in part of nominal variables and is unavoidably incomplete owing to missing information. The first step in the process codes all variables as binary data in order to accommodate the nominal variables. The second step calculates Spearman's rank correlation coefficients for pairs of variables. And the third step subjects the correlation coefficients to cluster analysis. Data related to 1,575 deaths attributed to tropical cyclones (also known as typhoons) that struck Taiwan between 2000 and 2015 are used to illustrate the method. The results yield two distinct groups of variables that are worthy of further exploration. 相似文献
250.
Associations of Forest Cover,Fragment Area,and Connectivity with Neotropical Understory Bird Species Richness and Abundance 总被引:1,自引:0,他引:1
Alexandre Camargo Martensen Milton Cezar Ribeiro Cristina Banks‐Leite Paulo Inácio Prado Jean Paul Metzger 《Conservation biology》2012,26(6):1100-1111
Theoretical and empirical studies demonstrate that the total amount of forest and the size and connectivity of fragments have nonlinear effects on species survival. We tested how habitat amount and configuration affect understory bird species richness and abundance. We used mist nets (almost 34,000 net hours) to sample birds in 53 Atlantic Forest fragments in southeastern Brazil. Fragments were distributed among 3 10,800‐ha landscapes. The remaining forest in these landscapes was below (10% forest cover), similar to (30%), and above (50%) the theoretical fragmentation threshold (approximately 30%) below which the effects of fragmentation should be intensified. Species‐richness estimates were significantly higher (F= 3715, p = 0.00) where 50% of the forest remained, which suggests a species occurrence threshold of 30–50% forest, which is higher than usually occurs (<30%). Relations between forest cover and species richness differed depending on species sensitivity to forest conversion and fragmentation. For less sensitive species, species richness decreased as forest cover increased, whereas for highly sensitive species the opposite occurred. For sensitive species, species richness and the amount of forest cover were positively related, particularly when forest cover was 30–50%. Fragment size and connectivity were related to species richness and abundance in all landscapes, not just below the 30% threshold. Where 10% of the forest remained, fragment size was more related to species richness and abundance than connectivity. However, the relation between connectivity and species richness and abundance was stronger where 30% of the landscape was forested. Where 50% of the landscape was forested, fragment size and connectivity were both related to species richness and abundance. Our results demonstrated a rapid loss of species at relatively high levels of forest cover (30–50%). Highly sensitive species were 3‐4 times more common above the 30–50% threshold than below it; however, our results do not support a unique fragmentation threshold. Asociaciones de la Cobertura Forestal, Superficie del Fragmento y Conectividad con la Riqueza y Abundancia de Aves Neotropicales de Sotobosque 相似文献