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971.
Sanket Mohapatra George Joseph Dilip Ratha 《Environment, Development and Sustainability》2012,14(3):365-387
Macro- and microeconomic evidence suggests a positive role of remittances in preparing households against natural disasters
and in coping with the loss afterward. Analysis of cross-country macroeconomic data shows that remittances increase in the
aftermath of natural disasters in countries that have a larger number of migrants abroad. Analysis of household survey data
in Bangladesh shows that per capita consumption was higher in remittance-receiving households than in others after the 1998
flood. Ethiopian households that receive international remittances seem to rely more on cash reserves and less on selling
household assets or livestock to cope with drought. In Burkina Faso and Ghana, international remittance-receiving households,
especially those receiving remittances from high-income developed countries, tend to have housing built of concrete rather
than mud and greater access to communication equipment, suggesting that they are better prepared against natural disasters. 相似文献
972.
Exhaust emissions of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin/furan (PCDD/F) congeners, tetra-octa PCDD/F homologues, 12 WHO 2005 polychlorinated biphenyl (PCB) congeners, mono-nona chlorinated biphenyl homologues, and 19 polycyclic aromatic hydrocarbons (PAHs) from three legacy diesel engines were investigated. The three engines tested were a 1985 model year GM 6.2 J-series engine, a 1987 model year Detroit Diesel Corporation 6V92 engine, and a 1993 model year Cummins L10 engine. Results were compared to United States’ mobile source inventory for on-road diesel engines, as well as historic and modern diesel engine emission values. The test fuel contained chlorine at 9.8 ppm which is 1.5 orders of magnitude above what is found in current diesel fuel and 3900 ppm sulfur to simulate fuels that would have been available when these engines were produced. Results indicate PCDD/F emissions of 13.1, 7.1, and 13.6 pg International Toxic Equivalency (I-TEQ) L−1 fuel consumed for the three engines respectively, where non-detects are equal to zero. This compares with a United States’ mobile source on-road diesel engine inventory value of 946 pg I-TEQ L−1 fuel consumed and 1.28 pg I-TEQ L−1 fuel consumed for modern engines equipped with a catalyzed diesel particle filter and urea selective catalytic reduction. PCB emissions are 2 orders of magnitude greater than modern diesel engines. PAH results are representative of engines from this era based on historical values and are 3-4 orders of magnitude greater than modern diesel engines. 相似文献
973.
Solomon Omwoma W. Nyaigoti Omwoyo Joseck O. Alwala David M. K. Ongeri Lagat C. Sylus Joseph O. Lalah 《The Environmentalist》2012,32(4):494-502
Due to intensive use of agronomic inputs in sugarcane farming, runoff water from these farms is loaded with high concentrations of nutrients. These nutrients find their way into rivers, lakes and sinks, eutrophicating them. Reducing the levels of these nutrients in runoff water from sugarcane farms before it is discharged into sinks will help solve the problems that arise out of eutrophication. This study employed a simple sedimentation method of making depressions in canals draining runoff water from sugarcane farms and emptying them fortnightly during the rainy season and monthly during the dry season. The method was found to significantly (p????0.05) reduce water conductivity (??S/cm), turbidity (Nephelometric Turbidity Units), total phosphates, nitrate?Cnitrogen, potassium, calcium, magnesium, iron, copper, sodium and zinc (ppm) in the dry season from 52.89, 148.70,0.87, 3.34, 446.00, 420.00, 205.00, 12,941.00, 261.00, 398.00, and 484.00 in untreated canals to 48.33, 30.22, 0.21, 2.95, 120.00, 154.00, 98.00, 456.00, 181.00, 234.00, and 311.00 in treated canals, respectively. And in the wet season, the parameters were reduced from 261.46, 719.30, 820.00, 25.16, 654.00, 549.00, 493.00, 19,230.00, 763.00, 748.00, and 903.00 to 128.67, 365.70, 3.47, 10.12, 136.00, 187.00, 167.00, 654.00, 207.00, 321.00, and 231.00, respectively. Dissolved oxygen significantly (p????0.05) increased from 5.11 to 8.14?ppm in the dry season and from 3.82 to 7.92?ppm wet season. Acidity reduced in the wet season from pH 5.02 to 6.20. It is, therefore, recommended that sugarcane farmers adopt this method for sustainability of aquatic systems within these zones. 相似文献
974.
Iftheker A. Khan Nirupam Aich A.R.M. Nabiul Afrooz Joseph R.V. Flora P. Ariette Schierz P. Lee Ferguson Tara Sabo-Attwood Navid B. Saleh 《Chemosphere》2013
Aggregate structure of covalently functionalized chiral specific semiconducting single-walled carbon nanotubes (SWNTs) was systematically studied employing static light scattering (SLS). Fractal dimensions (Df) of two specific chirality SWNTs—SG65 and SG76 with (6, 5) and (7, 6) chiral enrichments—were measured under four biological exposure media conditions, namely: Dulbecco’s Modified Eagle Medium (DMEM), Minimum Essential Medium (MEM), Roswell Park Memorial Institute (RPMI) 1640 medium, and 0.9% saline solution. The SWNTs exhibited chiral dependence on Df with SG65 showing more fractal or loosely bound aggregate structures, i.e., lower Df values (range of 2.24 ± 0.03 to 2.64 ± 0.05), compared to the SG76 sample (range of 2.58 ± 0.13 to 2.90 ± 0.08). All the Df values reported are highly reproducible, measured from multiple SLS runs and estimated with ‘random block-effects’ statistical analysis that yielded all p values to be <0.001. The key mechanism for such difference in Df between the SWNT samples was identified as the difference in van der Waals (VDW) interaction energies of these samples, where higher VDW of SG76 resulted in tighter packing density. Effect of medium type showed lower sensitivity; however, presence of di-valent cations (Ca2+) in DMEM and MEM media resulted in relatively loose or more fractal aggregates. Moreover, presence of fetal bovine serum (FBS) and bovine serum albumin (BSA), used to mimic the in vitro cell culture condition, reduced the Df values, i.e., created more fractal structures. Steric hindrance to aggregation was identified as the key mechanism for creating the fractal structures. Also, increase in FBS concentration from 1% to 10% resulted in increasingly lower Df values. 相似文献
975.
Hang Wang Joseph Holden Kandice Spera XinHua Xu ZaoDe Wang JingHua Luan Xin Xu ZhiJian Zhang 《Chemosphere》2013,90(6):1794-1804
Global warming is increasingly challenging for wetland ecological function. A temperature controlled microcosm system was developed to simulate climate change scenarios of an ambient temperature (control) and an elevated temperature (+5 °C). The effects and associated mechanisms of warming on phosphorus (P) fluxes at the sediment–water interface of six subtropical wetlands were investigated. The results indicated that P fluxes were generally enhanced under the experimental warming as measured by higher P concentrations in the porewater and overlying water as well as higher benthic P fluxes. The release of P from sediment to porewater occurred more strongly and quickly in response to experimental warming compared to the subsequent upward transfer into overlying water. The average accumulative benthic P output from the tested wetlands under the experimental warming was greater by 12.9 μg cm?2 y?1 (28%) for total P and 8.26 μg cm?2 y?1 (25%) for dissolved reactive P, compared to the ambient scenarios. Under warming the redistribution of P fractions in sediments occurred with greater NH4Cl–P and lower BD–P (extracted by a bicarbonate buffered dithionite solution) accompanied by greater NaOH–P. The higher temperature enhanced total phospholipid fatty acids. A shift in the microbial community was also observed with a relative dominance of fungi (a 4.7% increase) and a relative decline (by 18%) in bacterial abundance, leading to the higher secretion of phosphatase. Comparing between wetlands, the potential P fluxes in the nutrient-enriched wetlands were less impacted by warming than the other wetland types investigated. Thus wetlands characterized by low or medium concentrations of P in sediments were more susceptible to warming compared to P-rich wetlands. 相似文献
976.
In this study, seven soil and sedimentary humic acid samples were analyzed by synchronous scan fluorescence (SSF) spectroscopy. The spectra of these humic acids were compared to each other and characterized, based on three major SSF peaks centered at approximately 281, 367 and 470 nm. Intensity ratios were calculated based on these peaks that were used to numerically assist in source discrimination. All humic acid samples were then reacted with Ferrate(VI) and were again analyzed with SSF. Upon the addition of Ferrate(VI) SSF spectra were obtained which more readily differentiated humic acid source. This method will assist geochemists and water management districts in tracing sources of organic matter to receiving water bodies and may aid in the elucidation of the chemical nature of humic acids. 相似文献
977.
Max Eisenberg Joseph J. Topping 《Journal of environmental science and health. Part. B》2013,48(6):729-742
Abstract Organochlorine pesticide and herbicide levels were monitored in samples of a variety of edible finfish harvested from the Maryland section of the Chesapeake Bay and its tributaries over a five‐year period (1976–80). Qualitative and quantitative information was obtained for the various polychlorinated biphenyls (PCB's), heptachlor, α‐BHC, chlordane, DDD, DDE, DDT, dieldrin, endrin, heptachlor‐epoxide, lindane, mirex, methoxychlor, aldrin, toxaphene, hexachlorobenzene, kepone and dacthal. In addition to analyses of the flesh of the animals, organochlorine residue levels were determined in roe or gonad tissue of several samples. Striped bass, white perch and yellow perch samples showed significantly higher concentrations of certain of these substances in roe or gonad tissue, especially PCB's, chlordane, DDD and dieldrin. Significantly higher levels of six organochlorine residues were found in the gonad tissue of striped bass; however, similar studies on gonad tissue of American Shad, harvested from the same region, show no such enhancement. Rather, the reverse is true; levels of certain organochlorine residues are higher in flesh tissue. All mean values, and virtually all individual values of organochlorine concentrations in the edible portion of the fish were within the U.S. Food and Drug Administration guideline, where such guidelines have been established. 相似文献
978.
Christopher J. Williamson Paul L. Pennington Mary Carla Curran 《Journal of environmental science and health. Part. B》2013,48(8):810-816
The grass shrimp, Palaemonetes pugio, plays a large role in the marine ecosystem, serving as a vital link in the food web between many other species. Marine parasites such as the bopyrid isopod, Probopyrus pandalicola, reduce shrimp growth and reproductive output and may also cause P. pugio to be more vulnerable to the lethal effects of contaminants. The purpose of this study was to determine the toxicity of resmethrin and bifenthrin on the grass shrimp, P. pugio, infected with the bopyrid isopod, Probopyrus pandalicola. A 96-h static renewal test was conducted to determine the toxicity of the pyrethroid insecticides resmethrin and bifenthrin to grass shrimp, Palaemonetes pugio, parasitized with the bopyrid isopod, Probopyrus pandalicola. The results were then compared to similar tests utilizing unparasitized P. pugio. Parasitized P. pugio had lower 24-h LC50 (1.08 μg/L) and 96-h LC50 (0.43 μg/L) values for resmethrin than unparasitized P. pugio. However, LC50 ratio tests found that there was no significant difference between parasitized and unparasitized shrimp when affected by resmethrin (p = 0.1751 and 0.1108, respectively). In contrast, an LC10 ratio test indicated that there was a significant difference between parasitized and unparasitized P. pugio after 96 h (p < 0.0001). When subjected to bifenthrin, parasitized P. pugio had a higher 24-h LC50 (0.049 μg/L6) than unparasitized P. pugio. The LC50 ratio test established that the effects of bifenthrin on parasitized P. pugio when compared to unparasitized P. pugio were significantly different at 24 h (p = 0.0065). However, there were no significant differences between parasitized and unparasitized after 96 h (p = 0.4229). In conclusion, both resmethrin and bifenthrin are toxic to the grass shrimp, P. pugio, regardless of parasite presence, and parasitized shrimp may be more susceptible to lower doses of resmethrin (when exposed in the field). 相似文献
979.
Plants were examined at three different locations in the eastern part of the United States to determine whether damage from air pollution had occurred. This paper discusses sulfur dioxide damage in the metropolitan New York City area; hydrogen fluoride damage near a glass fiber manufacturing plant in the midwest; and hydrochloric acid mist and chlorine damage from a manufacturing operation in an eastern state. The symptoms that developed in vegetation were often found to be similar. Chemical and microscopical analyses were helpful in diagnosing the toxicants. 相似文献
980.