5,909 research outputs found

    Provision of water to the poor in Africa : experience with water standposts and the informal water sector

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    Standpipes that dispense water from utilities are the most common alternatives to piped water connections for poor customers in the cities of Sub-Saharan Africa. Fifty-five percent of the unconnected urban population relies on standpipes as their first water source. Other informal water providers include household resellers and a variety of water tankers and vendors, which are the first water source of 1 percent and 3 percent of the urban population, respectively. In the cities studied, the percentage of unconnected households ranges from 12 percent to 86 percent of the population. The percentage of unconnected people covered by standpipes is substantially higher for countries with higher rates of household connection, while the percentage of unconnected people covered by water tankers or water vendors is higher for countries with lower rates of household connection. Water prices in the informal market are much higher than for households with private connections or yard taps. Although standpipes are heavily subsidized by utilities, the prices charged by standpipe operators are closely related to the informal water reseller price. Standpipe management models also affect the informal price of water. For example, the shift from utilities management to delegated management models without complementary regulation or consumer information has often led to declines in service levels and increased prices. Standpipes are not the only or even the most efficient solution in peri-urban areas. Programs that promote private household connections and arrangements that improve pricing and services in the household resale market should also be considered by policy makers.Town Water Supply and Sanitation,Urban Water Supply and Sanitation,Water Supply and Sanitation Governance and Institutions,Water and Industry,Water Conservation

    A Hybrid Segmentation and D-bar Method for Electrical Impedance Tomography

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    The Regularized D-bar method for Electrical Impedance Tomography provides a rigorous mathematical approach for solving the full nonlinear inverse problem directly, i.e. without iterations. It is based on a low-pass filtering in the (nonlinear) frequency domain. However, the resulting D-bar reconstructions are inherently smoothed leading to a loss of edge distinction. In this paper, a novel approach that combines the rigor of the D-bar approach with the edge-preserving nature of Total Variation regularization is presented. The method also includes a data-driven contrast adjustment technique guided by the key functions (CGO solutions) of the D-bar method. The new TV-Enhanced D-bar Method produces reconstructions with sharper edges and improved contrast while still solving the full nonlinear problem. This is achieved by using the TV-induced edges to increase the truncation radius of the scattering data in the nonlinear frequency domain thereby increasing the radius of the low pass filter. The algorithm is tested on numerically simulated noisy EIT data and demonstrates significant improvements in edge preservation and contrast which can be highly valuable for absolute EIT imaging

    Prominence Mass Supply and the Cavity

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    A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet emission (EUV) surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the SDO/AIA 171\AA\ bandpass near the prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of our one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure

    The Affect Misattribution Procedure.

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    The Affect Misattribution Procedure (AMP) has been forwarded as one of the most promising alternatives to the Implicit Association Test and the evaluative-priming task for measuring attitudes such as prejudice indirectly. We investigated whether the AMP is indeed able to detect an evaluative out-group bias. In contrast to recent conclusions about the robustness of AMP effects, six out of seven pilot studies indicated that participants did not show any prejudice effects in the AMP. Yet, these pilot studies were not fully conclusive with regard to our research question because they investigated different domains of prejudice, used small sample sizes, and employed a modified AMP version. In a preregistered, high-powered AMP study, we therefore examined whether the standard AMP does reveal prejudice against Turks, the biggest minority in Germany, and found a significant, albeit very small prejudice effect. We discuss possible reasons for the AMP's weak sensitivity to evaluations in socially sensitive domains

    Exploring Pottery Production in Estremoz, Portugal

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    UID/HIS/04209/2013This paper discusses recent research exploring early modern pottery production associated with Estremoz, Portugal. Estremoz has played a prominent role in the historical narrative of Portuguese earthenwares stretching back to the 16th century, influencing research on both domestic and export consumption of Portuguese wares. New information presented here on the physical nature of Estremoz earthenware helps to deconstruct the area’s role in the production and distribution of ceramics in the early modern period.publishersversionpublishe

    Health and Social Service Needs of US-Citizen Children with Detained or Departed Immigrant Parents

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    The second report offers findings from fieldwork in five study sites in California, Florida, Illinois, South Carolina and Texas, examining the involvement of families with a deported parent with health and social service systems, as well as their needs and the barriers they face accessing such services. The researchers find that family economic hardship is highly prevalent following parental detention and deportation, while child welfare system involvement is rarer. Schools represent a promising avenue for interaction with these families and delivery of services, as school officials cannot inquire about immigration status and thus are perceived as safer intermediaries by unauthorized immigrant parents who may be skeptical of interaction with other government agencies. Other important sources of support include health providers, legal service providers and community- and faith-based organizations that immigrants trust
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