2,077 research outputs found

    Urban Public Works in Spatial Equilibrium: Experimental Evidence from Ethiopia

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    This paper evaluates a large urban public works program randomly rolled out across neighborhoods of Addis Ababa, Ethiopia. We find the program increased public employment and reduced private labor supply among beneficiaries and improved local amenities in treated locations. We then combine a spatial equilibrium model and unique commuting data to estimate the spillover effects of the program on private sector wages across neighborhoods: under full program rollout, wages increased by 18.6 percent. Using our model, we show that welfare gains to the poor are six times larger when we include the indirect effects on private wages and local amenities

    The JGrass-NewAge system for forecasting and managing the hydrological budgets at the basin scale: models of flow generation and propagation/routing

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    Abstract. This paper presents a discussion of the predictive capacity of the implementation of the semi-distributed hydrological modeling system JGrass-NewAge. This model focuses on the hydrological budgets of medium scale to large scale basins as the product of the processes at the hillslope scale with the interplay of the river network. The part of the modeling system presented here deals with the: (i) estimation of the space-time structure of precipitation, (ii) estimation of runoff production; (iii) aggregation and propagation of flows in channel; (v) estimation of evapotranspiration; (vi) automatic calibration of the discharge with the method of particle swarming. The system is based on a hillslope-link geometrical partition of the landscape, combining raster and vectorial treatment of hillslope data with vector based tracking of flow in channels. Measured precipitation are spatially interpolated with the use of kriging. Runoff production at each channel link is estimated through a peculiar application of the Hymod model. Routing in channels uses an integrated flow equation and produces discharges at any link end, for any link in the river network. Evapotranspiration is estimated with an implementation of the Priestley-Taylor equation. The model system assembly is calibrated using the particle swarming algorithm. A two year simulation of hourly discharge of the Little Washita (OK, USA) basin is presented and discussed with the support of some classical indices of goodness of fit, and analysis of the residuals. A novelty with respect to traditional hydrological modeling is that each of the elements above, including the preprocessing and the analysis tools, is implemented as a software component, built upon Object Modelling System v3 and jgrasstools prescriptions, that can be cleanly switched in and out at run-time, rather than at compiling time. The possibility of creating different modeling products by the connection of modules with or without the calibration tool, as for instance the case of the present modeling chain, reduces redundancy in programming, promotes collaborative work, enhances the productivity of researchers, and facilitates the search for the optimal modeling solution

    Estudios en suelos del Valle del Cauca con relación Ca:Mg invertida, 2. Efecto de varias enmiendas en las propiedades químicas y físicas de un suelo de Guayabito.

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    Se observó el efecto de 2 enmiendas en las propiedades físico-químicas de un suelo vallecaucano, que presenta la relación Ca:Mg, menor que la unidad. Se escogió un suelo de la serie Galpón, localizado en la Hacienda Guayabito y cuya relación Ca:Mg es bastante estrecha (0.3). Las muestras se tomaron de 0a 40 cm de profundidad. Las enmiendas utilizadas para tratar el suelo fueron: yeso y cloruro de calcio en mezclas con otras sales que contenían iones de K, NH4 o Ca, con el objeto de observar su efecto en el desplazamiento del Mg y el Na de cambio y en algunas propiedades físicas del mismo. Al analizar los suelos tratados y las aguas de lavado recogidas durante 66 días, se encontró que la adición de yeso produce resultados favorables en cuanto a absorción de Ca, desplazamiento de Mg e incremento en la permeabilidad. Cuando se incorporó yeso mezclado con (NH4)2SO4, hubo mayor desplazamiento del Mg y Na de cambio, comparado con los demás tratamientos. Los lavados del suelo sin adición de correctivos aumentaron notoriamente el Mg y el Na intercambiables, sin mejorar la permeabilidad del suelo. La incorporación al suelo de yeso, solo o mezclado con sales, parece ser más efectivo que el cloruro de calcio aplicado en solución a la superficie del suelo al iniciar el lavado, en cuanto a la absorción del Ca, al desplazamiento del Mg y Na y al mejoramiento de la permeabilidadGuayaba-Psidium guajav

    Rumo a um Observatório Latino-Americano do Clima e da Saúde: Seminário sobre Instrumentos e Metodologias

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    The study of the relationship between health and climate requires articulating various actors and disciplines. This paper presents the experience of the Latin American Seminar on Instruments and Methodologies for a climate and health observatory— held in Buenos Aires in 2019 and supported by the Latin American Center for Interdisciplinary Training (CELFI)—as a linking and training facility referencing the projects that are being carried out in this field throughout Latin American. This paper presents the design, contents, didactic approach and execution of the seminar, as well as its results regarding participation, products and evaluation. Likewise, the methodologies that could allow articulating different disciplines in a process of gainingknowledge about the climate-health relationship are reflected throughout this process. Finally, the main guidelines for this observatory, arising from an exchange with key actors, are set forth herein. The execution of the seminar, the projects presented as the products thereof, the discussions that arose during the exchange, and the need to continue with this work over the following months point out to the importance and necessity of building this observatory for Latin America and the Caribbean in an interdisciplinary way.El estudio de la relación entre clima y salud requiere la articulación de diversos actores y disciplinas. En este artículo se presenta la experiencia del Seminario Latinoamericano Instrumentos y Metodologías para un observatorio de clima y salud, realizado en Buenos Aires en 2019, apoyado por el Centro Latinoamericano de Formación Interdisciplinaria (CELFI), como un espacio de vinculación, capacitación y referencia a experiencias que se vienen desarrollando en este campo en América Latina. En este trabajo se presenta el diseño del seminario, su contenido, didáctica y desarrollo, así como los resultados en cuanto a participación, productos y evaluación. Asimismo, durante el proceso se reflexiona en torno a las metodologías que permitan articular diferentes disciplinas en un proceso de construcción de conocimiento sobre la relación clima-salud. Finalmente, se explicitan los principales lineamientos del observatorio, surgidos de una instancia de intercambio con actores clave. El desarrollo del seminario, los proyectos presentados como producto, las discusiones surgidas durante el intercambio y la continuidad de trabajo en los meses posteriores permiten dar cuenta de la importancia y necesidad de construir interdisciplinariamente este observatorio para América Latina y el Caribe.O estudo da relação entre o clima e a saúde requere a articulação de diversos atores e disciplinas. Neste artigo, apresenta-se a experiência do Seminário Latino-americano Instrumentos e Metodologias para um observatório de clima e saúde, realizado em Buenos Aires em 2019. Foi apoiado pelo Centro Latino-americano de Formação Interdisciplinar (CELFI), como espaço de vinculação, capacitação e referência das experiências que se estão a desenvolver neste campo na América Latina. Neste trabalho, apresenta- se a conceção do seminário, o seu conteúdo, dinâmica e desenvolvimento, bem como, os resultados em termos de participação, produtos e avaliação. Da mesma forma, durante o processo, é feita uma reflexão sobre as metodologias que permitem a articulação de diferentes disciplinas, num processo de construção do conhecimento sobre a relação clima-saúde. Por fim, explicitam-se as principais diretrizes do observatório, decorrentes de uma plataforma de intercâmbio dos atores chave. O desenvolvimento do seminário, os projetos apresentados como produto, as discussões ocorridas durante o intercâmbio e a continuidade de trabalho nos meses seguintes, permitem perceber a importância e a necessidade de construir este observatório interdisciplinar, para a América Latina e Caribe

    Aislamiento de bacterias nativas de Oncorhynchus mykiss con potencial probiótico frente a Yersinia ruckeri

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    The aim of this study was to identify native bacteria isolated from the intestinal tract of rainbow trout (Oncorhynchus mykiss) with probiotic properties against Yersinia ruckeri. In the study, 48 healthy trout from the hatchery of the Universidad Nacional del Altiplano (Puno, Peru) were used. The intestinal tract of the fry and juveniles was removed, and samples were taken from the intestinal mucosa. The samples were cultured on MRS agar and incubated at 30 °C for 24-48 h. The colonies were identified by their morphology and their inhibitory effect was evaluated in vitro against a Yersinia ruckeri strain isolated from a high mortality outbreak. Three isolates compatible with the genus Lactobacillus and one isolate compatible with the genus Bacillus were identified. These isolates showed inhibition halos greater than 9 mm in diameter against Y. ruckeri.  El objetivo del estudio fue identificar bacterias nativas aisladas del tracto intestinal de trucha arco iris (Oncorhynchus mykiss) con propiedades probióticas frente a Yersinia ruckeri. Se utilizaron 48 truchas sanas provenientes de la eclosería de la Universidad Nacional del Altiplano (Puno, Perú). El tracto intestinal de los alevines y juveniles fue extraído y se tomaron muestras de la mucosa intestinal. Las muestras fueron sembradas en agar MRS e incubadas a 30 °C por 24-48 h. Las colonias fueron identificadas por su morfología y se evaluó su efecto inhibitorio in vitro frente a una cepa de Yersinia ruckeri, aislada de un brote de alta mortalidad. Se identificaron tres aislados compatibles con el género Lactobacillus y un aislado compatible con el género Bacillus. Estos aislados mostraron halos de inhibición mayores a 9 mm de diámetro frente a Y. ruckeri. &nbsp

    Seroprevalencia del Virus de la Rinoneumonitis en Caballos (Equus caballus) del Perú

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    The aim of this study was to determine the seroprevalence of antibodies against Equine Herpes Virus type 1 (EHV-1) and Equine Herpes Virus type 4 (EHV-4), which causes rhinopneumonitis in horses. Blood samples (n=825) from Peruvian horses older than six months of age, both sexes, identified as racehorses, Peruvian Paso, equitation and criollo, in apparent healthy conditions, were collected for detection of neutralizing antibodies against EHV-1/EHV-4 by virus neutralization test. The 48.9 ± 5.3% (403/825) of the samples had antibodies against EHV-1/EHV-4. Antibody titers ranged from 2 to >256, where 58.5% ranged from 2 to 8, 29.5% from 16 to 64, and 11.9% from 128 to >256. The sex and region of the country did not represent a risk for presenting antibodies against EHV-1/EHV-4.El objetivo del presente estudio fue determinar la seroprevalencia del virus Herpes Equino tipo 1 o Herpes Equino tipo 4 (VHE-1/VHE-4), causante de la rinoneumonitis viral en caballos. Se recolectaron muestras de suero (n=825) de caballos mayores a seis meses de edad, entre machos y hembras, identificados como caballos de crianza familiar, de carrera, Peruano de Paso y de equitación, clínicamente normales, provenientes de varias regiones del Perú, para la detección de anticuerpos neutralizantes contra el VHE-1/VHE- 4 mediante la prueba de neutralización viral. El 48.9 ± 5.3% (403/825) de las muestras tuvieron anticuerpos contra el VHE-1/VHE-4. Los títulos de anticuerpos tuvieron un rango entre 2 a >256, siendo de 58.6% de títulos de 2 a 8, de 29.5% en títulos de 16 a 64, y de 11.9% en títulos de 128 a >256. La prueba de regresión logística indicó que las variables sexo y lugar de procedencia no constituyeron factores de riesgo para la presentación de anticuerpos contra el VHE-1/VHE-4

    Assessment of alternative divertor configurations as an exhaust solution for DEMO

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    Plasma exhaust has been identified as a major challenge towards the realisation of magnetic confinement fusion. To mitigate the risk that the single null divertor (SND) with a high radiation fraction in the scrape-of-layer (SOL) adopted for ITER will not extrapolate to a DEMO reactor, the EUROfusion consortium is assessing potential benefits and engineering challenges of alternative divertor configurations. Alternative configurations that could be readily adopted in a DEMO design include the X divertor (XD), the Super-X divertor (SXD), the Snowflake divertor (SFD) and the double null divertor (DND). The flux flaring towards the divertor target of the XD is limited by the minimum grazing angle at the target set by gaps and misalignments. The characteristic increase of the target radius in the SXD is a trade-off with the increased TF coil volume, but, ultimately, also limited by forces onto coils. Engineering constraints also limit XD and SXD characteristics to the outer divertor leg with a solution for the inner leg requiring up-down symmetric configurations. Capital cost increases with respect to a SND configuration are largest for SXD and SFD, which require both significantly more poloidal field coil conductors and in the case of the SXD also more toroidal field coil conductors. Boundary models with increasing degrees of complexity have been used to predict the beneficial effect of the alternative configurations on exhaust performance. While all alternative configurations should decrease the power that must be radiated in the outer divertor, only the DND and possibly the SFD also ease the radiation requirements in the inner divertor. These decreases of the radiation requirements are however expected to be small making the ability of alternative divertors to increase divertor radiation without excessive core performance degradation their main advantage. Initial 2D fluid modeling of argon seeding in XD and SFD configurations indicate such advantages over the SND, while results for SXD and DND are still pending. Additional improvements, expected from increased turbulence in the low poloidal field region of the SFD also remain to be verified. A more precise comparison with the SND as well as absolute quantitative predictions for all configurations requires more complete physics models that are currently only being developed

    Seroprevalencia del virus de Lengua Azul en cabras (Capra hircus) de la Región Norte del Perú

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    Bluetongue is an endemic disease in tropical and subtropical regions and the virus that causes the disease is transmitted by mosquito vectors of the genus Culicoides. The aim of this study was to determine the seroprevalence of the Bluetongue virus (BTV) in goats from the departments of Tumbes, Piura, Lambayeque, Cajamarca and La Libertad (Peru). Blood samples (n=424) were collected from goats older than 6 months of age, without clinical signs of disease and reared in extensive production systems between June and October 2017. The sera were analysed with commercial ELISA competition kits to determine antibodies against BTV. A seroprevalence of 23.8% (95% CI 19.84-28.16) was found. The results by department indicate that 34.9% (81/232), 20.9% (13/62), 9.5% (4/42) and 6.0% (3/50) and 0% (0/38) of samples from Piura, Tumbes, Cajamarca. Lambayeque and La Libertad, respectively, had antibodies against BTV. The seropositivity showed a positive association (p<0.05) with the age of the goats and negative (p<0.05) with the altitude of rearing.Lengua Azul es una enfermedad endémica en regiones tropicales y subtropicales y el virus causante de la enfermedad es transmitido por mosquitos vectores del género Culicoides. El objetivo del presente estudio fue determinar la seroprevalencia del virus de Lengua azul (VLA) en cabras de los departamentos de Tumbes, Piura, Lambayeque, Cajamarca y La Libertad (Perú). Se colectaron muestras de sangre (n=424) entre junio a octubre de 2017 de cabras mayores a 6 meses de edad, sin signos clínicos de enfermedad y criadas en forma extensiva. Los sueros fueron analizados con kits comerciales de ELISA de competición para determinar anticuerpos contra VLA. Se encontró una seroprevalencia de 23.8% (IC 95% 19.84-28.16). Los resultados por departamento indican que 34.9% (81/232), 20.9% (13/62), 9.5% (4/42) y 6.0% (3/50) y 0% (0/38) de las cabras de Piura, Tumbes, Cajamarca. Lambayeque y La Libertad, respectivamente, tuvieron anticuerpos contra el VLA. La seropositividad al VLA mostró una asociación positiva (p<0.05) con la edad de las cabras y negativa (p<0.05) con la altitud (msnm) de crianza
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