In the last few years, microblogging platforms such as Twitter have given rise to a deluge of textual data that can be used for the analysis of informal communication between millions of individuals. In this work, we propose an informationtheoretic approach to geographic language variation using a corpus based on Twitter. We test our models with tens of concepts and their associated keywords detected in Spanish tweets geolocated in Spain. We employ dialectometric measures (cosine similarity and Jensen-Shannon divergence) to quantify the linguistic distance on the lexical level between cells created in a uniform grid over the map. This can be done for a single concept or in the general case taking into account an average of the considered variants. The latter permits an analysis of the dialects that naturally emerge from the data. Interestingly, our results reveal the existence of two dialect macrovarieties. The first group includes a region-specific speech spoken in small towns and rural areas whereas the second cluster encompasses cities that tend to use a more uniform variety. Since the results obtained with the two different metrics qualitatively agree, our work suggests that social media corpora can be efficiently used for dialectometric analyses.

La educación superior requiere incrementar decididamente la retención de estudiantes, fenómeno que hasta hace algunos años no se consideraba relevante para el sistema pese a que sus cifras eran de magnitud, lo que en la actualidad ha cambiado, por la competencia, las presiones de las familias y de instituciones de financiamiento, y por las políticas de desarrollo de los países que se sustentan en el fortalecimiento del capital humano avanzado. El trabajo expone la magnitud del problema y sus principales impactos, revisándose sus estrategias de superación, las que implicaron desarrollo teórico y práctico de este campo de estudio, revisándose algunas soluciones emprendidas, las cuales se analizan en función de las estrategias que han sido más eficaces. Al tenor de lo expuesto, se proponen iniciativas para el sistema y las instituciones de educación en Chile.

21 h. a t 110" showed losses of dry weight, nitrogen, sulphur and all the amino-acids. The protein value of the heated material as shown by bioassay fell by a greater extent t h a n could be accounted for by losses of lysine, available lysine or the sulphur amino-acids. The limiting amino-acids in both original and heated material were the sulphur amino-acids. Balance stuJies of nitrogen, sulphur and lysine carried out concomitantly showed that the fall in the utilisation of lysine was largely accounted for by a reduction in its digestibility : the falls in utilisation of nitrogen and sulphur were mainly due to a reduced retention of the absorbed elements. The results are discussed in relation to possible types of reaction involved in the heat damage of proteins.

The aim of this work was to compare the quality of renal drainage obtained with two well-described procedures of diuretic renography (F+20 and F0 tests). We selected 36 clinically stable children, aged 10 days to 17 years, with unilateral (25) or bilateral (11) hydronephrosis, in whom both F+20 and F0 tests were successively performed. In all cases, a late image (PM) was acquired after micturition and after changing the position of the patient. The following parameters were calculated: the time to the maximum of the basic renogram (Tmax); and the normalized residual activity (NORA) and output efficiency (OE) at the end of the 20 min renogram, at the end of the furosemide test (35 min) and on the PM image. In F+20, the renal drainage was better on the PM image than at the end of the diuretic renogram, whereas, in F0, the renal drainage was better on the PM image than at the end of the 20 min diuretic renogram. When comparing F0 and F+20, both OE and NORA parameters revealed slightly better drainage at the end of the 20 min F0 renogram than at the end of the 35 min F+20 diuretic renogram. The drainage obtained on the late post-voiding image was comparable for both F0 and F+20 tests. In conclusion, the quality of drainage obtained during the F+20 and F0 procedures can easily be compared using both OE and NORA. A very similar quality of drainage was reached for both procedures when considering only the PM image. This PM view remains mandatory irrespective of the timing of the furosemide injection and despite the use of tracers with a high extraction rate.

Resumen Resumen Resumen Resumen ResumenEl artículo analiza las políticas de gestión de la enseñanza obligatoria en Chile al cumplirse próximamente dos décadas del proyecto educacional vigente, el cual ha logrado progresos importantes en materia de cobertura e incremento presupuestario, pero no han sido equivalentes sus avances en la calidad de la educación, pese a que en las comparaciones internacionales Chile mejora su posición relativa. El texto levanta un diagnostico del problema, cuyo núcleo central está constituido por la tensión entre la lógica del mercado con la cual opera el financiamiento escolar y la lógica de los derechos ciudadanos de educación que se ha buscado afanosamente implantar. Este camino está prácticamente agotado y tras dos décadas de forzar su andar demanda un cambio profundo en la manera cómo se diseña e implementan las políticas de gestión de educación obligatoria en Chile. El artículo releva el peso de la desigualdad social en el logro de los objetivos pedagógicos del sistema escolar público chileno, analiza las dificultades institucionales y, finalmente, evalúa algunos puntos críticos, generando proposiciones para la búsqueda de soluciones. Palabras clave: Gestión de la enseñanza obligatoria. Evaluación de la gestión escolar. Políticas de le gestión de la enseñanza pública en Chile. Desafíos de la gestión educacional.Políticas de gestão da educação pública escolar no Chile (1990Chile ( -2010: uma avaliação inicial Resumo O artigo analisa as políticas de gestão do ensino obrigatório no Chile ao se cumprir aproximamente duas décadas do projeto educacional vigente que logrou progressos importantes em matéria de cobertura e implementação, porém ensaio64.pmd

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There is a high proportion of abnormal DMSA scans in children with a first episode of acute pyelonephritis.

Purpose The purpose of this paper is to explore the possibility of producing Cu-based shape memory alloys (SMA) by means of direct metal laser fabrication (DMLF). Design/methodology/approach The fabrication approach consists of the combination of laser melting of a metallic powder with heating treatment in a controlled inert atmosphere. Three prospective Cu-Al-Ni alloy compositions were tested, and the effects of laser power, as well as laser exposure time, were verified. Findings All the processed materials were found to attain microstructures and phase change transformation temperatures typical of this type of SMA. Practical implications Further development of this technique will allow for fabrication of large elements with considerable shape memory effect, which are currently not viable due to high cost of nitinol. Originality/value This work showed a proof of concept toward the development of DMLF-based additive manufacturing of near net shape components of Cu-based SMAs from elemental powders.