1,661 research outputs found

    Cape Verde's infrastructure : a continental perspective

    Get PDF
    Cape Verde stands out in West Africa as a country whose economic geography poses major and unique challenges for infrastructure development. Its small population of half a million people is spread across a nine-island archipelago. The islands need complementary infrastructure in terms of roads, water, transport, ports, power, and ICT. Cape Verde already has well-developed infrastructure networks. Road density is relatively high, and most of the national network is paved. Almost all islands have port and airport facilities. Around 70 percent of the population has power and utility water. Indicators for ICT coverage -- penetration, bandwidth, submarine cable, private sector participation -- are relatively good. Nevertheless, prices for all services are exceptionally high. The quality of services is often deficient. At least half of the national road network is in poor condition; power supply is unreliable; and half of the population receives water from standposts. Cape Verde devotes around 147millionperyeartoinfrastructure(almost15percentofGDP),amongthehighestlevelsofinfrastructurespendingonthecontinent.Some147 million per year to infrastructure (almost 15 percent of GDP), among the highest levels of infrastructure spending on the continent. Some 50 million of that is lost each year to operations inefficiencies and underpricing. The country's main challenges are to improve infrastructure management and reduce high costs of services.Transport Economics Policy&Planning,Infrastructure Economics,Energy Production and Transportation,E-Business,Banks&Banking Reform

    CLASH: Weak-Lensing Shear-and-Magnification Analysis of 20 Galaxy Clusters

    Get PDF
    We present a joint shear-and-magnification weak-lensing analysis of a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19<z<0.69 selected from the Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis uses wide-field multi-color imaging, taken primarily with Suprime-Cam on the Subaru Telescope. From a stacked shear-only analysis of the X-ray-selected subsample, we detect the ensemble-averaged lensing signal with a total signal-to-noise ratio of ~25 in the radial range of 200 to 3500kpc/h. The stacked tangential-shear signal is well described by a family of standard density profiles predicted for dark-matter-dominated halos in gravitational equilibrium, namely the Navarro-Frenk-White (NFW), truncated variants of NFW, and Einasto models. For the NFW model, we measure a mean concentration of c200c=4.010.32+0.35c_{200c}=4.01^{+0.35}_{-0.32} at M200c=1.340.09+0.101015MM_{200c}=1.34^{+0.10}_{-0.09} 10^{15}M_{\odot}. We show this is in excellent agreement with Lambda cold-dark-matter (LCDM) predictions when the CLASH X-ray selection function and projection effects are taken into account. The best-fit Einasto shape parameter is αE=0.1910.068+0.071\alpha_E=0.191^{+0.071}_{-0.068}, which is consistent with the NFW-equivalent Einasto parameter of 0.18\sim 0.18. We reconstruct projected mass density profiles of all CLASH clusters from a joint likelihood analysis of shear-and-magnification data, and measure cluster masses at several characteristic radii. We also derive an ensemble-averaged total projected mass profile of the X-ray-selected subsample by stacking their individual mass profiles. The stacked total mass profile, constrained by the shear+magnification data, is shown to be consistent with our shear-based halo-model predictions including the effects of surrounding large-scale structure as a two-halo term, establishing further consistency in the context of the LCDM model.Comment: Accepted by ApJ on 11 August 2014. Textual changes to improve clarity (e.g., Sec.3.2.2 "Number-count Depletion", Sec.4.3 "Shape Measurement", Sec.4.4 "Background Galaxy Selection"). Results and conclusions remain unchanged. For the public release of Subaru data, see http://archive.stsci.edu/prepds/clash

    CLASH-X: A Comparison of Lensing and X-ray Techniques for Measuring the Mass Profiles of Galaxy Clusters

    Get PDF
    We present profiles of temperature (Tx), gas mass, and hydrostatic mass estimated from new and archival X-ray observations of CLASH clusters. We compare measurements derived from XMM and Chandra observations with one another and compare both to gravitational lensing mass profiles derived with CLASH HST and ground-based lensing data. Radial profiles of Chandra and XMM electron density and enclosed gas mass are nearly identical, indicating that differences in hydrostatic masses inferred from X-ray observations arise from differences in Tx measurements. Encouragingly, cluster Txs are consistent with one another at ~100-200 kpc radii but XMM Tx systematically decline relative to Chandra Tx at larger radii. The angular dependence of the discrepancy suggests additional investigation on systematics such as the XMM point spread function correction, vignetting and off-axis responses. We present the CLASH-X mass-profile comparisons in the form of cosmology-independent and redshift-independent circular-velocity profiles. Ratios of Chandra HSE mass profiles to CLASH lensing profiles show no obvious radial dependence in the 0.3-0.8 Mpc range. However, the mean mass biases inferred from the WL and SaWLens data are different. e.g., the weighted-mean value at 0.5 Mpc is = 0.12 for the WL comparison and = -0.11 for the SaWLens comparison. The ratios of XMM HSE mass profiles to CLASH lensing profiles show a pronounced radial dependence in the 0.3-1.0 Mpc range, with a weighted mean mass bias of value rising to ~0.3 at ~1 Mpc for the WL comparison and of 0.25 for SaWLens comparison. The enclosed gas mass profiles from both Chandra and XMM rise to a value 1/8 times the total-mass profiles inferred from lensing at 0.5 Mpc and remain constant outside of that radius, suggesting that [8xMgas] profiles may be an excellent proxy for total-mass profiles at >0.5 Mpc in massive galaxy clusters.Comment: Accepted to ApJ; 24 pages; scheduled to appear in the Oct 10, 2014 issue. This version corrects the typographical error in the superscripts for Equation (2) to include the square of (r/r_core). The correct version of this equation was used in the analysi

    Composición e invarianza factorial del Autoinforme de Barreras para la Práctica de Ejercicio Físico (ABPEF-M) en universitarios mexicanos deportistas

    Get PDF
    The aim of this research was to analyze the psychometric properties proposed by Rodríguez-Villalobos et al. (2017) for the Barriers for the Practice of Physical Activity Scale (ABPEF-M) in university athletes &nbsp;mens and women. The total sample has been composed by 413 Mexican university athletes, 174 women and 239 mens, with ages from 18-26 years (M = 20.76, SD = 2.06). The factor structure of questionnaire has been analized through the confirmatory factor analysis. This analysis shows that a tetrafactorial structure (body image, fatigue, obligations, and environment) is viable and adequate for the total sample and the populations of mens and woman. The four factors structure, according to statistical and substantive criteria, has shown adequate indicators of reliability and validity adjustment. On the other hand, the factorial structure, the factorial loads and the intercepts are considered invariant according to the variable gender; however, no differences were found between mens and women athletes in their perception of the presence of barriers in the four dimensions studied.El presente estudio analiza las propiedades psicométricas propuestos por Rodríguez-Villalobos, Viciana, Tristán y Blanco (2017) para el Autoinforme de Barreras para la Práctica de Ejercicio Físico (ABPEF-M) en hombres y mujeres deportistas universitarios. La muestra total fue de 413 universitarios mexicanos deportistas 174 mujeres y 239 hombres, con edades comprendidas entre 18-26 años (M = 20.76; DE = 2.06). La estructura factorial del cuestionario se analizó mediante análisis factoriales confirmatorios. Los análisis, muestran que una estructura tetrafactorial (imagen corporal, fatiga, obligaciones y ambiente) es viable y adecuada tanto para la muestra total como para las poblaciones de hombres y mujeres. La estructura de cuatro factores, atendiendo a criterios estadísticos y sustantivos, ha mostrado adecuados indicadores de ajuste de fiabilidad y validez. Además, la estructura factorial, las cargas factoriales y los interceptos se consideran invariantes de acuerdo al género; sin embargo, no se encontraron diferencias entre hombres y mujeres deportistas en cuanto su percepción sobre la presencia de barreras en las cuatro dimensiones estudiadas.O objetivo deste estudo foi examinar a estructura e invariância de gênero Auto-relato de Barreiras à Prática de Exercício Físico (ABPEF-M) proposto por Rodríguez-Villalobos et al. (2017) em atletas universitários mexicanos. A amostra total foi de 413 atletas mexicanos universitários, 174 mulheres e 239 homens, com idades entre 18-26 anos (M = 20.76; DP = 2.06). A estrutura fatorial do questionário foi analisada por análises fatoriais confirmatórias. Os resultados mostraram que uma estrutura de quatro fatores (imagem corporal/ ansiedade social físico, fadiga/ preguiça, obrigações/ falta de tempo, e meio ambiente/ instalações) é viável e adequado tanto para a amostra total e para as populações de homens e mulheres. Com base em critérios estatísticos e substantivos, a estrutura de quatro fatores mostrou adequada confiabilidade e validade dos indicadores de ajuste. Além disso, a estrutura fatorial, as cargas fatoriais e os interceptos eram invariantes de acordo com o gênero. Não foram encontradas diferenças entre atletas homens e mulheres na sua percepção da presença de barreiras nas quatro dimensões estudadas

    The Contribution of Halos with Different Mass Ratios to the Overall Growth of Cluster-Sized Halos

    Get PDF
    We provide a new observational test for a key prediction of the \Lambda CDM cosmological model: the contributions of mergers with different halo-to-main-cluster mass ratios to cluster-sized halo growth. We perform this test by dynamically analyzing seven galaxy clusters, spanning the redshift range 0.13<zc<0.450.13 < z_c < 0.45 and caustic mass range 0.41.50.4-1.5 1015h0.73110^{15} h_{0.73}^{-1} M_{\odot}, with an average of 293 spectroscopically-confirmed bound galaxies to each cluster. The large radial coverage (a few virial radii), which covers the whole infall region, with a high number of spectroscopically identified galaxies enables this new study. For each cluster, we identify bound galaxies. Out of these galaxies, we identify infalling and accreted halos and estimate their masses and their dynamical states. Using the estimated masses, we derive the contribution of different mass ratios to cluster-sized halo growth. For mass ratios between ~0.2 and ~0.7, we find a ~1 σ\sigma agreement with \Lambda CDM expectations based on the Millennium simulations I and II. At low mass ratios, 0.2\lesssim 0.2, our derived contribution is underestimated since the detection efficiency decreases at low masses, 2×1014\sim 2 \times 10^{14} h0.731h_{0.73}^{-1} M_{\odot}. At large mass ratios, 0.7\gtrsim 0.7, we do not detect halos probably because our sample, which was chosen to be quite X-ray relaxed, is biased against large mass ratios. Therefore, at large mass ratios, the derived contribution is also underestimated.Comment: 25 pages, 16 figures, 6 tables, 2 machine readable tables, accepted for publication in ApJ, updated acknowledgements and data table format modifications mad

    CLASH: Mass Distribution in and around MACS J1206.2-0847 from a Full Cluster Lensing Analysis

    Get PDF
    We derive an accurate mass distribution of the galaxy cluster MACS J1206.2-0847 (z=0.439) from a combined weak-lensing distortion, magnification, and strong-lensing analysis of wide-field Subaru BVRIz' imaging and our recent 16-band Hubble Space Telescope observations taken as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program. We find good agreement in the regions of overlap between several weak and strong lensing mass reconstructions using a wide variety of modeling methods, ensuring consistency. The Subaru data reveal the presence of a surrounding large scale structure with the major axis running approximately north-west south-east (NW-SE), aligned with the cluster and its brightest galaxy shapes, showing elongation with a \sim 2:1 axis ratio in the plane of the sky. Our full-lensing mass profile exhibits a shallow profile slope dln\Sigma/dlnR\sim -1 at cluster outskirts (R>1Mpc/h), whereas the mass distribution excluding the NW-SE excess regions steepens further out, well described by the Navarro-Frenk-White form. Assuming a spherical halo, we obtain a virial mass M_{vir}=(1.1\pm 0.2\pm 0.1)\times 10^{15} M_{sun}/h and a halo concentration c_{vir} = 6.9\pm 1.0\pm 1.2 (\sim 5.7 when the central 50kpc/h is excluded), which falls in the range 4 <7 of average c(M,z) predictions for relaxed clusters from recent Lambda cold dark matter simulations. Our full lensing results are found to be in agreement with X-ray mass measurements where the data overlap, and when combined with Chandra gas mass measurements, yield a cumulative gas mass fraction of 13.7^{+4.5}_{-3.0}% at 0.7Mpc/h (\approx 1.7r_{2500}), a typical value observed for high mass clusters.Comment: Accepted by ApJ (30 pages, 17 figures), one new figure (Figure 10) added, minor text changes; a version with high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/MACS1206/ms_highreso.pd

    Three Gravitationally Lensed Supernovae Behind CLASH Galaxy Clusters

    Get PDF
    We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z = 0.345), and Abell 383 (z = 0.187), respectively. Each SN was detected in Hubble Space Telescope (HST) optical and infrared images. Based on photometric classification, we find that SNe CLO12Car and CLN12Did are likely to be Type Ia supernovae (SNe Ia), while the classification of SN CLA11Tib is inconclusive. Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, we infer that SN CLO12Car was approximately 1.0 +/- 0.2 mag brighter than field SNe Ia at a similar redshift and ascribe this to gravitational lens magnification. Similarly, SN CLN12Did is approximately 0.2 +/- 0.2 mag brighter than field SNe Ia. We derive independent estimates of the predicted magnification from CLASH strong+weak lensing maps of the clusters: 0.83 +/- 0.16 mag for SN CLO12Car, 0.28 +/- 0.08 mag for SN CLN12Did, and 0.43 +/- 0.11 mag for SN CLA11Tib. The two SNe Ia provide a new test of the cluster lens model predictions: we find that the magnifications based on the SN Ia brightness and those predicted by the lens maps are consistent. Our results herald the promise of future observations of samples of cluster-lensed SNe Ia (from the ground or space) to help illuminate the dark-matter distribution in clusters of galaxies, through the direct determination of absolute magnifications.Comment: ApJ in pres

    Optimization of the surface properties of nanostructured Ni–W alloys on steel by a mixed silane layer

    Get PDF
    Ni–W nanostructured coatings electrodeposited on steel by galvanostatic pulses were functionalized by tetraethoxysilane (TEOS) and octadecyltrichlorosilane (OTS) in a two-step procedure. A silica-rich layer is formed by the reaction of TEOS with the metal coating surface oxides, which allows a further reaction with OTS forming a hydrocarbon-silica outer network. This mixed silane layer provides hydrophobicity and improves the corrosion behavior of the Ni–W surface coatings without modifying their excellent mechanical properties.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    Pasturas estivales en el sur de Corrientes

    Get PDF
    Este libro se basa en una experiencia de validación a campo, surgida de la iniciativa de un productor miembro del grupo CREA Curuzú Cuatiá. La idea fue generar información de pasturas, para solucionar una problemática forrajera del sistema productivo. Para ello, se decide trabajar en conjunto con INTA y de esta forma dar el mayor rigor posible a las mediciones, de manera de valorizar el esfuerzo realizado.EEA MercedesFil: Barbera, Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Benitez, Julio Cesar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Pizzio, Rafael Mario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Maidana, Carlos Emilio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Escalante, María Susana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Bendersky, Diego. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Mc Lean, Guillermo Donald. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Tamborelli, Melina Rut. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Ramírez, Ricardo Ramón. Actividad privada; ArgentinaFil: Ramirez, Ramón Ricardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Ramirez, Mario Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Maidana, Carlos Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Zapata, Patricio José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Fernandez, Juan Ramón. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes); ArgentinaFil: Beccaria, Mauricio Daniel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes). Agencia De Extensión Rural Curuzú Cuatiá; ArgentinaFil: Preisz, Victor Hernan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes (Corrientes). Agencia De Extensión Rural Curuzú Cuatiá; Argentin

    Compartiendo saberes de educación y humanidades

    Get PDF
    Los capítulos referentes a este libro tratan diversos temas tales como: 1) la construcción de los estudiantes de la licenciatura en químico farmacéutico biólogo el juicio valorativo y personaI deI significado en su desarroIIo profesionaI desde eI punto de vista axiológico, 2) se realiza un estudio en el Plantel Cuauhtémoc con Ia finaIidad de orientar a Ia comunidad estudiantiI aI tratamiento deI probIema de los residuos sólidos desde su etapa de diagnóstico hasta una propuesta de solución de la problemática, 3) se analiza como a nivel básico se construye el conocimiento y la participación del género en los estudiantes, en donde se observa que el papel del docente es un promotor importante, 4) es un tema que actualmente está causando mucho interés tanto en la educación como el la población en general, las redes sociales que actuaImente ese consideran un medio de comunicación con mucha influencia dentro de la sociedad, 5) se adentra al campo de la psicología y la tanatología ante los recursos resilientes que presentan las familias ante la muerte de un hijo, 6) es una investigación dedicada a identificar Ias diferentes percepciones que tienen las mujeres y los hombres en relación a la felicidad y la desdicha dentro del matrimonio, 7) es un análisis Transgeneracional para aportar las referencias familiares que permiten la permanencia del abuso sexual infantil en tres generaciones, de las cuales en la última generación se rompe ese secreto avallazador al romper el silencio, 8) es un ensayo acerca del juego terapéutico desde el punto de vista psicoanalítico, en el que se advierte ese juego en el que entra el paciente con el psicoanalista, 9) la metodología de la observación para la integración de la pericial en psicología, en donde se denotan desde la parte jurídica como se fundamente esta pericial y fortalece el logro del dictamen para tener un buen dictamen, 10) es una propuesta de construcción y validez del instrumento BP-22 Bienestar Psicológico en el ámbito de la educación superior, 11) se identifica a Ios procesos eIectoraIes como complicados, de tal manera que abre un panorama al marketing de los partidos políticos para conducir la voluntad ciudadana, y además ayuda al posicionamiento de los partidos, 12) aporta una base sobre Ios procesos identificatorios en eI movimiento estudiantiI de Ia UNAM deI año de I999, pIanteándoIo desde dos ejes de análisis: las identidades universitarias y el apartado del texto, que permiten configurar eI movimiento estudiantiI como un acontecimiento capaz de generar articulaciones nuevas de solidaridad. AI finaI deI Iibro se encuentran Ias síntesis curricuIares de cada uno de los autores, que aportaron sus investigaciones para la integración y generación de nuevos aportes científicos.Como su nombre lo indica COMPARTIENDO SABERES DE EDUCACIÓN Y HUMANIDADES, es un Iibro que denota eI deseo de integrar conocimiento para la comunidad estudiantil, llevarlos al interés de la investigación a través de la participación de los investigadores de diferentes áreas como: la educación, las ciencias sociales y las humanidades. Que les permite tener no solo un espacio en la difusión de los avances de sus estudios, sino que además permite el generar el interés de quién lo lee en diferentes formas de investigación, se encuentran estudios tanto cualitativos como cuantitativos, desde descriptivos hasta un nivel de intervención en la práctica de estas áreas.Universidad Autónoma del Estado de méxic
    corecore