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This paper goes some way towards redressing the lack of geographical literature on charity through exploring the geography of the British domestic charitable sector. The size and geography of the third sector is outlined, followed by an analysis of how almshouses can be understood as inherently geographical and deeply embedded in local social networks of inclusion as well as exclusion. 相似文献
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Stacin Martin Chen Zhu Joseph Rule Robert Ford Yee Soong 《Geochimica et cosmochimica acta》2005,69(6):1543-1553
Experiments of Zn2+ and Fe3+ coprecipitation as a function of pH were conducted in the laboratory at ambient temperature and pressure. X-ray diffraction patterns of the coprecipitates show two broad peaks at 0.149 and 0.258 nm, which is consistent with published patterns for pure 2-line ferrihydrite. Zn2+ uptake occurred at pH ≥5 while Fe3+ precipitation occurred between pH 3 and 4, although both Zn2+ and Fe3+ were present in the same solution during the entire range of pH titration. High-resolution transmission electron microscopy shows that the coprecipitates are 2 to 6 nm sized single crystalline particles but aggregated to 50 to 400 nm sized clusters. Analytical electron microscopy indicated that the 5% atomic Zn with respect to Fe was homogeneously distributed. No segregated phases were found in the clusters or at single crystal edges, which is consistent with published extended X-ray absorption fine structure (EXAFS) results at similar Zn/(Zn + Fe) ratios. Hence, occlusion and surface precipitation may be excluded as possible coprecipitation mechanisms. The bulk solution Zn2+ sorption edge was fitted to both solid solution and generalized diffuse layer surface complexation models. However, a solid solution model is inconsistent with published EXAFS results that show tetrahedral polydentate Zn2+ complexes sharing apices with Fe3+octahedra. 相似文献
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Large amounts of digital data must be analyzed and integrated to generate mineral potential maps, which can be used for exploration targeting. The quality of the mineral potential maps is dependent on the quality of the data used as inputs, with higher quality inputs producing higher quality outputs. In mineral exploration, particularly in regions with little to no exploration history, datasets are often incomplete at the scale of investigation with data missing due to incomplete mapping or the unavailability of data over certain areas. It is not always clear that datasets are incomplete, and this study examines how mineral potential mapping results may differ in this context. Different methods of mineral potential mapping provide different ways of dealing with analyzing and integrating incomplete data. This study examines the weights of evidence (WofE), evidential belief function and fuzzy logic methods of mineral potential mapping using incomplete data from the Carajás mineral province, Brazil to target for orogenic gold mineralization. Results demonstrate that WofE is the best one able to predict the location of known mineralization within the study area when either complete or unacknowledged incomplete data are used. It is suggested that this is due to the use of Bayes’ rule, which can account for “missing data.” The results indicate the effectiveness of WofE for mineral potential mapping with incomplete data. 相似文献
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Torbern Tagesson Jonas Ardö Idrissa Guiro Ford Cropley Cheikh Mbow Stephanie Horion 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2016,116(2):93-109
Africa is a sink of carbon, but there are large gaps in our knowledge regarding the CO2 exchange fluxes for many African ecosystems. Here, we analyse multi-annual eddy covariance data of CO2 exchange fluxes for a grazed Sahelian semi-arid savanna ecosystem in Senegal, West Africa. The aim of the study is to investigate the high CO2 exchange fluxes measured at the peak of the rainy season at the Dahra field site: gross primary productivity and ecosystem respiration peaked at values up to ?48 μmol CO2 m?2 s?1 and 20 μmol CO2 m?2 s?1, respectively. Possible explanations for such high fluxes include a combination of moderately dense herbaceous C4 ground vegetation, high soil nutrient availability and a grazing pressure increasing the fluxes. Even though the peak net CO2 uptake was high, the annual budget of ?229 ± 7 ± 49 g C m?2 y?1 (±random errors ± systematic errors) is comparable to that of other semi-arid savanna sites due the short length of the rainy season. An inter-comparison between the open-path and a closed-path infrared sensor indicated no systematic errors related to the instrumentation. An uncertainty analysis of long-term NEE budgets indicated that corrections for air density fluctuations were the largest error source (11.3% out of 24.3% uncertainty). Soil organic carbon data indicated a substantial increase in the soil organic carbon pool for the uppermost .20 m. These findings have large implications for the perception of the carbon sink/source of Sahelian ecosystems and its response to climate change. 相似文献
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R. D. Preece M. S. Briggs G. N. Pendleton W. S. Paciesas J. L. Matteson D. L. Band L. A. Ford 《Astrophysics and Space Science》1995,231(1-2):207-210
The BATSE Spectroscopy Detectors (SDs) each have a thin beryllium window which allows detection of photons down to 5 keV. Until recently, exploitation of low-energy SD discriminator data has been held up by a lack of knowledge of its energy coverage. A recent series of in-flight changes in the instrument configuration has allowed the SD discriminators to be calibrated fairly accurately. With this in hand, we have surveyed BATSE GRBs for such features as X-ray precursors and after-glows in the roughly 5-10 keV band. For a large percentage of the BATSE bursts, no emission is observed in this energy band. In some cases where low-energy emission has been observed, ratios of flux histories indicate differential spectral evolution. In addition, we have obtained joint spectral fits between the low-energy data and the regular SD data, showing that a single spectral model is sometimes insufficient to fit the entire energy range. 相似文献