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

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

Qualitative comparison of several phase correction algorithms in single-image in-line X-ray phase contrast tomography

In recent years, phase contrast has gained importance in the field of X-ray imaging and more particular in high-resolution X-ray computed tomography or micro-CT. For phase propagation imaging, no additional hardware or specific setup is required, which makes the effect inherent to micro-CT where it is manifested as an edge-enhancement effect. As such, it can be beneficial for qualitative analysis of a 3D volume. Nevertheless, it induces unreal gray values and is thus often considered as an imaging artefact which hinders proper quantitative 3D analysis. Several methods exist to reduce this phase contrast effect or to retrieve the phase information from the mixed phase-and-amplitude images. In this presentation, a comparison will be made between 2 phase retrieval algorithms and 2 phase correction algorithms. Of these 2 latter, one can be performed on the reconstructed volume, which clearly facilitates the operation of phase correction

Industria de bienes de equipo: Inserción comercial y cambio estructural

The aim of this paper is to analyze the Spanish trade flows of capital goods in the EU. This analysis is based on the evolution of quality integration ratios: the technology and range position of the exports. The main conclusion is that, even accepting the diversity of positions and trends observed inside the capital goods industry, it seems to be positioned in a relatively subordinate position, specialized in segments of lower-middle market and technology range.El texto examina el comercio exterior de la industria de bienes de equipo de la economía española en el entorno comunitario. Dicho análisis se realiza a partir de la evolución de un conjunto de indicadores reveladores de la calidad de la inserción comercial: el nivel tecnológico y la posición de gama. La principal conclusión es que, aun aceptando la diversidad de posiciones y trayectorias observadas en la industria, parece que ésta ocupa un espacio relativamente subordinado, instalada en segmentos de mercado de media-baja tecnología y gama.Industria, Bienes de equipo, Competitividad, Inserción comercial, Cambio estructural, Economía española, Industry, Capital goods, Competitiveness, Trade integration, Structural change, Spanish economy.

Forced oscillations of isothermal axisymmetric liquid bridges

The forced oscillations of a liquid column held by surface tension forces between two solid supports are analysed by using an inviscid linear three-dimensional model. The liquid bridge frequency response (interface deformation and pressure and velocity fields) when one (or both) of the supporting disks are oscillated or when the gravity field changes with time is calculated. The influence of a surrounding media of non-negligible density (outer bath) is included in the model. The latter consideration allows the use of experiments done on ground using the neutral buoyancy technique to validate the model for later use in flight experiments (where air is used as surrounding media and there is no need for considering its effect). In normal gravity conditions, the most appropriate way to obtain near cylindrical configurations is to surround the bridge with a matching density media and thus, the inertial effects of that fluid modifies significantly the dynamic behaviour

Teacher reactions to the use of blogs in the classroom.

En este artículo presentamos un estudio exploratorio cualitativo cuyo objetivo fue co - no cer la percepción que una muestra de 25 profesores de enseñanza primaria, secundaria y uni versitaria, que utilizan habitualmente los blogs en sus aulas, sobre las posibilidades edu cativas que, en su opinión, tiene este recurso en rendimiento y comportamiento de los alum nos. Se realizó una investigación cualitativa mediante la técnica de relatos. La extracción de la información contenida en los relatos fue llevada a cabo mediante Análisis de Con - tin gencias utilizando software experimental como GestMagister y GOLUCA, para elaborar una representación gráfica en forma de Red Asociativas Pathfinder de las categorías más im portantes encontradas. Según estas categorías y sus relaciones identificamos las princi pa les posibilidades educativas del uso de los blogs, en opinión de los participantes.In this article we present a cualitative study whose objective was to find out the perception of 25 teachers of primary, high school and university who usually use blogs for their lessons, regarding the educational posibilities which, in their opionions, this resource has in the performance and behaviour of the pupils. A qualitative investigation was made using the story telling technique. The extraction of information of the tales was made using Risk Analysis, helped by experimental software, in the form of GestMagister and GOLUCA, to make a graphical representation in the shape of an Pathfinder Asociative Network of the most important categories found. With these categories and their relations we identify the main educational posibilities of the use of blogs in the opinion of the participants.peerReviewe

Creando música con la pizarra digital : comunicación presentada al II Congreso DIM-Aulatic 18 y 19 de marzo del 2010

Se propone la composición colaborativa de una pieza musical con alumnos de 6º de Primaria usando una Pizarra Digital Interactiva (PDI). Se analizan las actitudes de los alumnos ante aspectos concretos del día a día del aula de música (mediante la técnica de Diferencial Semántico) para contrastar el uso de las PDI con otras metodologías más tradicionales.We propose the collaborative composition of a piece of music with students from 6th grade using an interactive whiteboard (IWB). We analyze the students' attitudes to specific aspects of everyday classroom music (through the Semantic Differential technique) to contrast the use of IWB with other more traditional methodologies