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261.
Mathieu Ouédraogo Robert Zougmoré Abdoulaye S. Moussa Samuel T. Partey Philip K. Thornton Patti Kristjanson Ndèye Y. B. Ndour Léopold Somé Jesse Naab Moussa Boureima Lamissa Diakité Carlos Quiros 《Regional Environmental Change》2017,17(2):437-449
Agricultural practices have constantly changed in West Africa, and understanding the factors that have driven the changes may help guide strategies to promote sustainable agriculture in the region. To contribute to such efforts, this paper analyzes drivers of change in farming practices in the region using data obtained from surveys of 700 farming households in five countries (Burkina Faso, Ghana, Mali, Niger and Senegal). The results showed that farmers have adopted various practices in response to the challenges they have faced during the last decade. A series of logit models showed that most changes farmers made to their practices are undertaken for multiple reasons. Land use and management changes including expanding farmed areas and using mineral fertilization and manure are positively related to perceived changes in the climate, such as more erratic rainfall. Planting new varieties, introducing new crops, crop rotation, expanding farmed area and using pesticides are positively associated with new market opportunities. Farm practices that require relatively high financial investment such as use of pesticides, drought-tolerant varieties and improved seeds were positively associated with the provision of technical and financial support for farmers through development projects and policies. Changes in markets and climate are both helping to promote needed changes in farming practices in West Africa. Therefore, policies that foster the development of markets for agricultural products, and improved weather- and climate-related information linked to knowledge of appropriate agricultural innovations in different environments are needed. 相似文献
262.
The 2004 tsunami and mental health in Thailand: a longitudinal analysis of one‐and two‐year post‐disaster data
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Some 280,000 people died in the Indian Ocean tsunami on 26 December 2004. This cohort study examined its impact on mental health one and two years later. It did so by investigating the association between six consequent variables (personal injury, loss of home, loss of business, death of a family member, injury to a family member, or loss of a family member's business) and mental health, as measured by the 36‐item Short Form Health Survey (SF‐36), among residents in four provinces of Thailand. One year later, participants who suffered a personal injury, the loss of a business, or the loss of a family member reported poorer mental health than those who were unaffected. Two years later, participants who experienced the loss of a family member reported poorer mental health than those who were unaffected. This research shows that such a disaster may have long‐lasting ramifications for mental health, and that diverse losses may influence mental health differently. 相似文献
263.
Uchendu Eugene Chigbu Anna Schopf Walter T. de Vries Fahria Masum Samuel Mabikke Danilo Antonio 《Journal of Environmental Planning and Management》2017,60(9):1622-1639
There is tenure insecurity around land ownerships and land rights in most developing countries. There are also many land-use planning projects being implemented in these countries. Often, land-use planning exists in these countries but is not formally linked with tenure security. This study argues that combining them by conducting land-use planning in a way that promotes tenure security presents a new approach. A central premise for the rationale of this intervention is that processes of land-use planning may inadvertently increase tenure security. By way of methodology, it evaluates land-use planning case studies from Africa, Asia and South America. It uses the three case study examples to build a case for making tenure security one of the major planned outcomes of a land-use planning process and provides a detailed framework for operationalising the concept. Its main contribution to the literature is that it introduces the concept of tenure responsive land-use planning. 相似文献
264.
Lead (Pb) sorption onto oxide surfaces in soils may strongly influence the risk posed from incidental ingestion of Pb-contaminated soil. Lead was sorbed to model oxide minerals of corundum (alpha-Al(2)O(3)) and ferrihydrite (Fe(5)HO(8).4H(2)O). The Pb-sorbed minerals were placed in a simulated gastrointestinal tract (in vitro) to simulate ingestion of Pb-contaminated soil. The changes in Pb speciation were determined using extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge spectroscopy (XANES). Both corundum (sorption maximum of 2.13 g kg(-1)) and ferrihydrite (sorption maximum of 38.6 g kg(-1)) have been shown to sorb Pb, with ferrihydrite having a very high affinity for Pb. The gastric bioaccessible Pb for corundum was >85% for corundum when the concentration of Pb was >200 mg kg(-1). Bioaccessible Pb was not detectable at =200 mg kg(-1). Bioaccessible Pb ranged from 53 to 88% for ferrihydrite. The bioaccessible Pb was below detection limits for the intestinal phase in the ferrihydrite system. Solid phase speciation identified both inner- (mononuclear bidentate) and outer-sphere species for Pb sorbed to corundum, while only an inner-sphere (mononuclear bidentate) complex was found for ferrihydrite. Although corundum and ferrihydrite can bind Pb, they fail to significantly reduce gastric bioaccessible Pb but do reduce intestinal bioaccessible Pb. Treatment of Pb-contaminated soil with corundum or ferrihydrite may reduce Pb solubility under field soil conditions of pH > 4. However, much of the sorbed Pb will become bioaccessible under gastric conditions (pH 1.5-2.5) if this soil is ingested. Caution should be used before using these materials to remediate a soil where soil ingestion is an important exposure pathway. 相似文献
265.
Isotopic evidence of nitrate sources and denitrification in the Mississippi River, Illinois 总被引:6,自引:0,他引:6
Anthropogenic nitrate (NO3-) within the Mississippi-Atchafalaya River basin and discharge to the Gulf of Mexico has been linked to serious environmental problems. The sources of this NO3- have been estimated by others using mass balance methods; however, there is considerable uncertainty in these estimates. Part of the uncertainty is the degree of denitrification that the NO3- has undergone. The isotopic composition of NO3- in the Mississippi River adjacent to Illinois and tile drain (subsurface drain) discharge in agricultural areas of east-central Illinois was examined using N and O isotopes to help identify the major sources of NO3- and assess the degree of denitrification in the samples. The isotopic evidence suggests that most of the NO3- in the river is primarily derived from synthetic fertilizers and soil organic N, which is consistent with published estimates of N inputs to the Mississippi River. The 1:2 relationship between delta18O and delta15N also indicate that, depending on sample location and season, NO3- in the river and tile drains has undergone significant denitrification, ranging from about 0 to 55%. The majority of the denitrification appears to have occurred before discharge into the Mississippi River. 相似文献
266.
The globally distributed fallout radionuclide 137Cs was monitored in 25 resident and 22 migratory fish species collected from some regions of west and east coast of southern
India to establish a baseline data. The samples were collected during June 2008 to June 2009. Higher level of 137Cs was noted in planktivorous fishes and lower level in herbivores. A significant variation in 137Cs was observed between fishes with different feeding habits and different migratory pattern. Oceanodromic migratory fishes
displayed higher cesium levels than other migratory types. Similarly, migratory fishes displayed higher 137Cs concentration compared to resident fishes. The overall range of 137Cs varied from 0.06 to 0.3 Bq/kg in fishes. The biological concentration varied from 55 to 250. The average external dose
rate to fishes was calculated to be 2.7 × 10−7 μGy/h, while the internal dose rate varied from 8.50 × 10−6 to 5.27 × 10−5 μGy/h. The hazard quotient for fishes was found to be less than 1. The average intake of 137Cs via fishes to the public was calculated to be 3.5 Bq/year and subsequently the committed effective dose was 0.05 μSv/year.
The data obtained were less than global average and comparable to those of many regions. 相似文献
267.
Fumes from a group of gas metal arc welding (GMAW) processes used on stainless steel were generated using three different metal transfer modes and four different shield gases. The objective was to identify and measure manganese (Mn) species in the fumes, and identify processes that are minimal generators of Mn species. The robotic welding system was operated in short-circuit (SC) mode (Ar/CO2 and He/Ar), axial spray (AXS) mode (Ar/O2 and Ar/CO2), and pulsed axial-spray (PAXS) mode (Ar/O2). The fumes were analyzed for Mn by a sequential extraction process followed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, and by X-ray diffraction (XRD). Total elemental Mn, iron (Fe), chromium (Cr) and nickel (Ni) were separately measured after aqua regia digestion and ICP-AES analysis. Soluble Mn2+, Fe2+, Fe3+, and Ni2+ in a simple biological buffer (phosphate-buffered saline) were determined at pH 7.2 and 5.0 after 2 h incubation at 37 C by ion chromatography. Results indicate that Mn was present in soluble form, acid-soluble form, and acid-soluble form after reduction by hydroxylamine, which represents soluble Mn0 and Mn2+ compounds, other Mn2+ compounds, and (Mn3+ and Mn4+) compounds, respectively. The dominant fraction was the acid-soluble Mn2+ fraction, but results varied with the process and shield gas. Soluble Mn mass percent in the fume ranged from 0.2 to 0.9%, acid-soluble Mn2+ compounds ranged from 2.6 to 9.3%, and acid plus reducing agent-soluble (Mn3+ and Mn4+) compounds ranged from 0.6 to 5.1%. Total Mn composition ranged from 7 to 15%. XRD results showed fumes had a crystalline content of 90-99% Fe3O4, and showed evidence of multiple Mn oxides, but overlaps and weak signals limited identification. Small amounts of the Mn2+ in the fume (<0.01 to ≈ 1% or <0.1 to ≈ 10 microg ml(-1)) and Ni2+ (<0.01 to ≈ 0.2% or <0.1 to ≈ 2 mg ml(-1)) ions were found in biological buffer media, but amounts were highly dependent on pH and the welding process. Mn generation rates for the fractions were tabulated, and the influence of ozone is discussed. The conclusions are that exposures to welding fumes include multiple Mn species, both soluble and insoluble, and that exposures to Mn species vary with specific processes and shield gases. 相似文献
268.
Peretyatko A Teissier S De Backer S Triest L 《Environmental monitoring and assessment》2012,184(3):1517-1531
Phytoplankton, zooplankton, submerged vegetation and main nutrients have been monitored in 48 eutrophic ponds from the Brussels
Capital Region (Belgium) between 2005 and 2008. Nine ponds have been biomanipulated in order to improve their ecological quality
and prevent the occurrence of noxious cyanobacterial blooms. The 4-year study of a large number of ponds allowed identification
of the factors having the strongest influence on phytoplankton growth. Continuous monitoring of the biomanipulated ponds allowed
the significance of changes caused by biomanipulation to be tested as well as the main reasons of biomanipulation successes
and failures to be elucidated. The main factors controlling phytoplankton in the ponds studied appeared to be grazing by large
cladocerans and inhibition of phytoplankton growth by submerged vegetation. Biomanipulation resulted in a significant decrease
in phytoplankton biomass in general and biomass of bloom-forming cyanobacteria in particular that were associated with a significant
increase in large Cladocera density and size. In six out of nine ponds biomanipulation resulted in the restoration of submerged
vegetation. The maintenance of the restored clearwater state in the biomanipulated ponds was strongly dependent on fish recolonisation
and nutrient level. In the absence of fish, the clearwater state could be maintained by submerged vegetation or large zooplankton
grazing alone. In case of fish recolonisation, restoration of extensive submerged vegetation could buffer, to a considerable
degree, the effect of fish except for ponds with high nutrient levels. 相似文献
269.
270.
Richard A. Retting Jonathan Williams Samuel I. Schwartz 《Journal of Safety Research》2000,31(4):203-210
There are approximately 600,000 highway bridges in the United States. These structures differ from surface streets and highways in terms of their physical properties and operational characteristics, which in turn, affect the risk of motor-vehicle crashes and the kinds of crashes that occur. The purpose of this study was to identify motor-vehicle crash patterns and contributing factors to bridge crashes and related countermeasure opportunities on four urban bridges in the New York metropolitan area. A crash typology was developed using the narratives and diagrams in police crash reports in addition to standard police classifications of crashes. The final dataset contained records of 1,381 police-reported crashes. The four bridges studied had higher crash rates than their respective approach roads. Four major crash types accounted for approximately 90% of the bridge crashes. Primary collision factors are reviewed, and potential countermeasures are discussed. 相似文献