1,860 research outputs found
The Impact of Microfinance in the Developing World
This research paper is about the impact of microfinance in the developing world. Microfinance is the provision of small-scale loans to low-income clients, most commonly in the developing world, for the purposes of beginning a microenterprise. The subject is a topic of contention in the global development community. My paper will explore the different arguments surrounding the concept
Trace elements in stream bed sediments from agricultural catchments (Gascogne region, S-W France): Where do they come from?
The Gascogne region (SW of France) is cultivated for more than 75% of the area. 83 samples of stream bed sediments were collected in three main Gascogne river basins (Gers, Save and Touch, left tributaries of the Garonne river) to evaluate the impact of agricultural practices on trace elements behavior. Eight potential harmful elements (PHE) (Cr, Co, Ni, Cu, Zn, As, Cd and Pb), four reference elements for normalization (Sc, Cs, Al and Fe) and four major elements (Mn, Ca, Mg and P) were considered. The average trace element concentrations in the fine fractions (b63 μm) are in the decreasing order: ZnNCrNNiNPbNCuNCoNAsNScNCsNCd. Geochemical investigations and an original approach combining regression analysis and chemical sequential extraction allowed to select the most adequate reference material (regional molasse)and reference element (Cs) for normalization procedure. The enrichment factor (EF) is generally lower than 2.5, particularly for Cr, Ni, Cu, As, Zn; however, 23% of the sampling stations are more contaminated (2.5bEFb4.5), particularly for Cd, Pb and Co. The PHE in the Gascogne river sediments are mainly originated from natural weathering processes; nevertheless, anthropogenic contribution could represent up to 34% of the total sediment content. For lead, geochemical and isotopic methods gave very similar anthropogenic contributions (24% and 22%, respectively). The enrichment of Cu, Pb, Zn, Co, As, Ni, Cr was mainly related to global and local atmospheric deposition of industrial emissions and gasoline combustion, and was associated to forested catchments. All PHE's are controlled by clay and oxi-hydroxides minerals. Cdwas the only PHE enriched downstreamcultivated catchments and this enrichmentwas linked to Ca and P. This indicates a major origin of Cd fromfertilizer inputs and a main control by carbonate mineral
Distribution and origin of lead in stream sediments from small agricultural catchments draining Miocene molassic deposits (SW France)
Total Pb concentrations and isotopic composition were determined in stream-bed sediments and bedrock from 29 small agricultural or forested catchments in the Gascogne area (SW France). The contribution of Pb from various natural and anthropogenic sources was investigated in this rural area which is very weakly impacted by industrial or urban emissions. Environmental parameters in catchments (importance of forest cover, organic matter and oxide content in sediments) were considered. A combination of geochemical (enrichment calculation, sequential extraction) and isotopic investigations was performed to constrain the origin of Pb and the distribution of anthropogenic Pb in sediments. Most of the sediments have low total Pb content compared to other agricultural regions more impacted by industrial or urban emissions. The results indicated a moderate but significant Pb enrichment, particularly for catchments draining forested areas. This enrichment was positively related to organic C content in sediment and catchment forest cover, whereas in entirely cultivated catchments it was related to Fe-oxide content. An average anthropogenic end-member was determined using Pb isotopes, and was supposed to be representative of background atmospheric Pb pollution, with a weak influence of Pb from recent gasoline and local fertiliser spreading. The amount of anthropogenic Pb (Pbanthr) in sediments estimated using a geochemical approach (mean 63.7 ± 20.4%) was higher than that estimated using an isotopic approach (mean 36.6 ± 17.8%), but the same trend was observed among the samples, except for low anthropogenic contributions. The distribution of Pbanthr in sediments from weakly forested catchments indicated a strong affinity for carbonates and Fe-oxides. Amorphous Fe-oxides became preferential trapping compounds as soon as Pb enrichment increased and carbonate content decreased. Finally, in cultivated catchments, organic C was not a main trapping component for Pbanthr in sediments
Toxicity of Pb and of Pb/Cd combination on the springtail Folsomia candida in natural soils: Reproduction, growth and bioaccumulation as indicators
The toxicity of Pb and Cd+Pb was assessed on the Collembola F. candida in two cultivated soils (SV and AU) with low organic matter (OM) content and circumneutral to basic pH, and an acid forested soil (EPC) with high OM content. Collembola reproduction and growth as well as metal content in Collembola body, in soil, exchangeable fraction and soil solutions, pH and DOC were investigated. Pb and Cd+Pb were the highest in exchangeable fraction and soil solution of the acidic soils. Soil solution pH decreased after metal spiking in every soil due to metal adsorption, which was similar for Cd and the highest in AU for Pb. With increasing Pb and Cd+Pb, the most important reproduction decrease was in EPC soil. The LOEC for reproduction after metal addition was 2400 (Pb) and 200/2400 (Cd/Pb), 1200 and 100/1200, 300 and 100/1200 μg g−1 for AU, SV and EPC, respectively. The highest and the lowest Pb toxicity was observed for EPC and AU bulk soil, respectively. The metal in Collembola increased with increasing soil concentration, except in AU, but the decreasing BFsolution with increasing concentrations indicates a limited metal transfer to Collembola or an increased metal removal. Loading high Pb concentrations decreases Cd absorption by the Collembola, but the reverse was not true. The highest Pb toxicity in EPC can be explained by pH and OM content. Because of metal complexation, OM might have a protective role but its ingestion by Collembola lead to higher toxicity. Metal bioavailability in Collembola differs from soil solution indicating that soil solution is not sufficient to evaluate toxicity in soil organisms. The toxicity as a whole decreased when metals were combined, except for Pb in AU, due to adsorption competition between Cd and Pb on clay particles and OM sites in AU and EPC soils, respectively
Determining cadmium critical concentrations in natural soils by assessing Collembola mortality, reproduction and growth
The toxicity of cadmium for the Collembola Folsomia candida was studied by determining the effects of increasing Cd concentrations on growth, survival and reproduction in three cultivated and forested soils with different pH (4.5–8.2) and organic matter content (1.6–16.5%). The Cd concentration in soil CaCl2 exchangeable fraction, in soil solution and in Collembola body was determined. At similar total soil concentrations, the Cd concentration in soil solutions strongly decreased with increasing pH. Reproduction was the most sensitive parameter. Low organic matter content was a limiting factor for reproduction. Effect of Cd on reproduction was better described by soil or body concentrations than by soil solution concentration. Values of EC50-Repro expressed on the basis of nominal soil concentration were 182, 111 and 107 μg g−1, respectively, for a carbonated cultivated soil (AU), an acid forested soil with high organic matter (EPC) and a circumneutral cultivated soil with low organic content (SV). Sensitivity to Cd was enhanced for low OM content and acidic pH. The effect of Cd on reproduction is not directly related to Cd concentration in soil solution for carbonated soil: a very low value is found for EC50-Repro (0.17) based on soil solution for the soil with the highest pH (AU; pH=8.2). Chronic toxicity cannot be predicted on the basis of soluble fractions. Critical concentrations were 8×10−5, 1.1, 0.3 μg mL−1, respectively, for AU, EPC and SV soils
Maturity and Fecundity of the White Perch, Morone americana, in Western Lake Erie
Author Institution: Sandusky Biological Station, Great Lakes Fishery Laboratory, U.S. Fish and Wildlife ServiceAmong white perch {Morone americana) collected from bottom trawl catches in 1984 and commercial trap net catches in 1985, all males were mature at age 2, and all females by age 3. Fecundity estimates for 50 females collected in May, 1985 ranged from 64,480 to 388,736 eggs (x ± SE=174,945±10,198)
Korea housing guaranty program 1977-78
노트 : Evaluation period: 1977-197
Promoting quality in low-cost gas sensor devices for real-world applications
Recent advancements in metal oxide semiconductor sensors enable system integrators to make sensor devices without the traditional complications of operating barebone sensor components. Anyone, so it seems, can put together multi-sensor-systems by combining an integrated sensor subsystem with a small piece of digital infrastructure, resulting in low-cost sensor systems or sensor networks for all kinds of applications. With low energy consumption, the deployment of close meshed sensor networks is becoming a reality, promising high density data for big data models. However, data quality is not necessarily a feature of such devices, since the device output signals are heavily processed and the insight into the actual operating technique is black-boxed by the respective sensor manufacturer. High volume production of a sensor model requires widely applicable output information, yet this mainstreaming negatively impacts quality control efforts on the system level as well as niche applications that require specialized operation modes. This article exemplarily examines the measurement chain of typical metal oxide semiconductor sensor applications and deduces requirements for a technically sound advancement of the subject for research and commercial purposes. Equivalent considerations can be made for any low-cost sensor principle and their respective challenges. The conclusion urges all stakeholders participating in the development and marketing of sensor devices to advance a scientifically valid state of knowledge and to educate their customers and even the general public accordingly
Mechanical Miracles: Automata in Ancient Greek Religion
What role did technologies of automation play in the ancient Greek religious experience? In this dissertation, I investigate the use of self-animated machines, known as automata, in their religious contexts. As no thorough examination of the topic has been undertaken to date, the thesis brings together the ancient evidence for the use of large automata in festival processions, as well as smaller gadgets set up in temples. Having gathered together the primary sources attesting to the phenomenon, I insist on the importance of moving beyond viewing these self-animated machines as mere illustrations of ancient mechanics. Instead, I investigate the subtleties behind the interaction of the spheres of mechanical ingenuity and religious spectacle in the ancient Greek world. I look at the ancient evidence in order to understand both the symbolic and aesthetic value of the machines, and how they might have been conceptualised by spectators given a disposition to interpret animation according to a certain framework. The study investigates the place that automata occupied more broadly in the ancient imagination in order to understand the role of mechanical ingenuity when it combines with religious occasion and religious space. We will see, above all, the way in which technologies of animation were used in religious contexts to provoke a particular type of ‘thaumastic’ awe in the ancient Greek viewer. The project’s originality lies in the way in which it intersects with a number of scholarly discourses: It takes part in the reassessment of the use and sophistication of technology in the ancient world, contributes to discussions on human-divine relations and, in particular, it introduces the novel element of human artifice (technē) in shaping ancient Greek religious experience
- …