1,625 research outputs found

    Alignment effects in clusters of galaxies

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    We present the measurement of 204 position angles of the brightest cluster galaxies in a sample of southern clusters (Abell, Corwin and Ollowing 1989). We analyze cluster-cluster alignment effects in this sample and extend it with previous sample of Abell clusters in the northern hemisphere. Binggeli's (1982) test is used with distances derived from the log(cz-m₁₀) giving an alignment signal consistent with redshift derived distances. Our results suggest a weak but statistically significant signal of alignment of the brightest galaxy in a cluster with the projected vector toward the nearest approximately to a 30% excess of brightest cluster galaxies pointing to the nearest cluster of galaxies. The mean acute angle between the galaxy position angle and the direction towards the nearest neighbor is = 39°±2°, or less. The scale of the detected anisotropy is D=15 Mpc/h. The statistical results are controlled by means of Montecarlo simulations and several points concerning the cluster-cluster alignment effects are discussed.Asociación Argentina de Astronomí

    Incorporating the gender dimension on the use of rice technologies in Latin America

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    A presentation on the role of men and women in rice in Peru, Bolivia and Ecuador. In collaboration with the CGIAR Research Program on Rice

    Bilingual and intercultural strategies on transmigrant families

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    El artículo presenta los resultados de una investigación cuyo objetivo fundamental ha sido analizar e identificar cuáles son las estrategias –tanto bilingües como interculturales– que despliegan familias transmigrantes hispano-germanas. La metodología que hemos seguido se instala en el enfoque biográficonarrativo, de tal manera que hemos reconstruido las etapas y proyectos migratorios de dichas familias, interesándonos por el discurso de los padres y madres a propósito de las estrategias, objetivos y teorías que subyacen a las prácticas, así como el interés que muestran por mantener y potenciar las competencias bilingües e interculturales en su cotidianidad. Una vez analizado todo el material empírico, los resultados que presentamos se organizan en torno a cuatro grandes dimensiones de análisis: a) «Prácticas bilingües», donde describimos qué estrategias siguen las familias para el fomento y potenciación del bilingüismo; b) «Teorías cotidianas sobre la interculturalidad», entendidas como aquellos discursos que se refieren a «teorías» y «niveles de análisis» sobre la percepción y aceptación de la diversidad cultural; c) una tercera denominada «Redes sociales», referida a la participación activa de los miembros del grupo familiar en redes –ya sean familiares, de ocio, laborales o de otro tipo– y que, según sus discursos, les permite fomentar y mantener la transmigración, el bilingüismo y las competencias interculturales; y, por último, d) el «Cosmopolitismo», referido a la selección de discursos de las familias que muestran motivos, valoraciones y actitudes positivas acerca de la diversidad lingüística y cultural, al margen de que éstas sean practicadas o no.This article presents the results of a research project whose aim is to analyze and identify the bilingual and intercultural strategies employed by the Spanish-German transmigrant families. Through the use of a biographical-narrative approach, we have reconstructed the migratory phases and itineraries of there families, emphasizing the parents’ underlying discourses on strategies, objectives and their subjacent theories on their children’s bilingual practices as well as on their specific interest on keeping and strengthening their children’s bilingual and intercultural competences. After presenting the analyzed empirical data, the results obtained are grouped into four broad dimensions: a) «bilingual practice», i.e. those strategies adopted by families to promote and strengthen bilingualism; b) interculturality life world theories, i.e. the ideas and levels of analysis about perceiving and accepting cultural diversity; c) «social networks», i.e. active participation in kin, labor, leisure or other social networks which, according to their discourse, foster transmigration, bilingualism and intercultural competences; and d) «cosmopolitanism» as a particular kind of discourse chosen by the interviewed families and which –without regard to their actual practices– reflect positive motives, values and attitudes identified with cultural and linguistic diversity, no matter if they are used or no

    Predicting the evolution of neck pain episodes in routine clinical practice

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    [EN] Background: The objective of this study was to develop models for predicting the evolution of a neck pain (NP) episode. Methods: Three thousand two hundred twenty-five acute and chronic patients seeking care for NP, were recruited consecutively in 47 health care centers. Data on 37 variables were gathered, including gender, age, employment status, duration of pain, intensity of NP and pain referred down to the arm (AP), disability, history of neck surgery, diagnostic procedures undertaken, imaging findings, clinical diagnosis, and treatments used. Three separate multivariable logistic regression models were developed for predicting a clinically relevant improvement in NP, AP and disability at 3 months. Results: Three thousand one (93.5%%) patients attended follow-up. For all the models calibration was good. The area under the ROC curve was ≥0.717 for pain and 0.664 for disability. Factors associated with a better prognosis were: a) For all the outcomes: pain being acute (vs. chronic) and having received neuro-reflexotherapy. b) For NP: nonspecific pain (vs. pain caused by disc herniation or spinal stenosis), no signs of disc degeneration on imaging, staying at work, and being female. c) For AP: nonspecific NP and no signs of disc degeneration on imaging. d) For disability: staying at work and no signs of facet joint degeneration on imaging. Conclusions: A prospective registry can be used for developing valid predictive models to quantify the odds that a given patient with NP will experience a clinically relevant improvementSIThis study was funded by the Spanish Back Pain Research Network (REIDE), a Spanish not-for-profit organization which specializes in neck and back pain research. REIDE is funded by: a) The Kovacs Back pain Unit in the Hospital Universitario HLA-Moncloa, a private organization specializing in neck and back pain, dedicated to medical research, health care and promotion of public health, with no links to the health industry b) Fundación ASISA, a Spanish non-profit institution linked to a health insurance company (ASISA) owned by a physician’s cooperativ

    Detection of mild cognitive impairment in people older than 65 years of age and its relationship to cardiovascular risk factors (DECRIVAM)

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    [ENG]Background: Studies centered on the detection of cognitive impairment and its relationship to cardiovascular risk factors in elderly people have gained special relevance in recent years. Knowledge of the cardiovascular risk factors that may be associated to cognitive impairment could be very useful for introducing treatments in early stagesthereby possibly contributing to improve patient quality of life. The present study explores cognitive performance in people over 65 years of age in Salamanca (Spain), with special emphasis on the identification of early symptoms of cognitive impairment, with the purpose of detecting mild cognitive impairment and of studying the relationships between this clinical situation and cardiovascular risk factors. Methods/Design: A longitudinal study is contemplated. The reference population will consist of 420 people over 65 years of age enrolled through randomized sampling stratified by healthcare area, and who previously participated in another study. Measurement: a) Sociodemographic variables; b) Cardiovascular risk factors; c) Comorbidity; d) Functional level for daily life activities; and e) Study of higher cognitive functions based on a neuropsychological battery especially adapted to the evaluation of elderly people. Discussion: We hope that this study will afford objective information on the representative prevalence of cognitive impairment in the population over 65 years of age in Salamanca. We also hope to obtain data on the relationship between cognitive impairment and cardiovascular risk factors in this specific population group. Based on the results obtained, we also will be able to establish the usefulness of some of the screening tests applied during the study, such as the Mini-Mental State Examination and the 7 Minute Screen test. Trial registration: ClinicalTrials.gov: NCT0132719

    Machine learning techniques to select variable stars

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    In order to perform a supervised classification of variable stars, we propose and evaluate a set of six features extracted from the magnitude density of the light curves. They are used to train automatic classification systems using state-of-the-art classifiers implemented in the R statistical computing environment. We find that random forests is the most successful method to select variables

    Intercomparison of spectroradiometers and Sun photometers for the determination of the aerosol optical depth during the VELETA-2002 field campaign

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    [ 1] In July 2002 the VELETA-2002 field campaign was held in Sierra Nevada ( Granada) in the south of Spain. The main objectives of this field campaign were the study of the influence of elevation and atmospheric aerosols on measured UV radiation. In the first stage of the field campaign, a common calibration and intercomparison between Licor-1800 spectroradiometers and Cimel-318 Sun photometers was performed in order to assess the quality of the measurements from the whole campaign. The intercomparison of the Licor spectroradiometers showed, for both direct and global irradiances, that when the comparisons were restricted to the visible part of the spectrum the deviations were within the instruments' nominal accuracies which allows us to rely on these instruments for measuring physical properties of aerosols at the different measurement stations. A simultaneous calibration on AOD data was performed for the Cimel-318 Sun photometers. When a common calibration and methodology was applied, the deviation was lowered to much less than 0.01 for AOD. At the same time an intercomparison has been made between the AOD values given by the spectroradiometers and the Sun photometers, with deviations obtained from 0.01 to 0.03 for the AOD in the visible range, depending on the channel. In the UVA range, the AOD uncertainty was estimated to be around 0.02 and 0.05 for Cimel and Licor respectively. In general the experimental differences were in agreement with this uncertainty estimation. In the UVB range the AOD measurements should not be used due to maximum instrumental uncertainties

    Mapping of the atmospheric deposition of sulfur and nitrogen during the dry season 2016 in the Metropolitan zone of Merida, Yucatan, Mexico

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    Abstract. Atmospheric deposition of sulfur and nitrogen was measured in the Metropolitan Area of Merida, Yucatan in Mexico during the dry season of 2016. Passive samplers type "throughfall" based on ion exchange resins were used to measure the hydrological flows in a total of 9 sampling sites distributed throughout the city. The ions retained in the resin were analyzed by turbidimetry and colorimetry to determine Ammonium, Nitrate and Sulfate. Deposition fluxes of S and N obtained were 6.25 and 5.19 Kg ha-1 yr-1. Both, sulfur and nitrogen atmospheric deposition fluxes were higher in urban sites, exceeding almost 2 times, the reference values proposed internationally for sensitive ecosystems. From the analysis of wind roses and air masses trajectories, it was possible to establish that during this climatic season, in addition to the local vehicular emissions, regional emissions generated upwind (from E-SE) contributed to atmospheric deposition of these ions. Finally, N and S deposition fluxes and their relationship with criteria pollutants were assessed, and maps for atmospheric deposition fluxes of Ammonium, Sulfate and Nitrate were generated using geo-statistical tools in order to identify critical deposition zones in this Metropolitan zone
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