3,422 research outputs found

    Crop intensification, land use, and on-farm energy-use efficiency during the worldwide spread of the green revolution

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    We analyzed crop production, physical inputs, and land use at the country level to assess technological changes behind the threefold increase in global crop production from 1961 to 2014. We translated machinery, fuel, and fertilizer to embedded energy units that, when summed up, provided a measure of agricultural intensification (human subsidy per hectare) for crops in the 58 countries responsible for 95% of global production. Worldwide,there was a 137% increase in input use per hectare, reaching 13 EJ, or 2.6% of the world´s primary energy supply, versus only a 10% increase in land use. Intensification was marked in Asia and Latin America, where input-use levels reached those that North America and Europe had in the earlier years of the period; the increase was more accentuated, irrespective of continent, for the 12 countries with mostly irrigated production. Half of the countries (28/58), mainly developed ones, had an average subsidy >5 GJ/ha/y (with fertilizers accounting for 27% in 1961 and 45% in 2014), with most of them (23/28) using about the same area or less than in 1961 (net land sparing of 31 Mha). Most of the remaining countries (24/30 with inputs <5 GJ/ha/y), mainly developing ones, increased their cropped area (net land extensification of 135 Mha). Overall, energy-use efficiency (cropoutput/inputs) followed a U-shaped trajectory starting at about 3 and finishing close to 4. The prospects of a more sustainable intensification are discussed, and the inadequacy of the land-sparing model expectation of protecting wilderness via intensified agriculture is highlighted.Fil: PELLEGRINI, PEDRO. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: FERNANDEZ, Roberto J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

    Biosafety and Dual-Use Scientific Research

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    Presentation at the Controlling Dangerous Pathogens Project Regional Workshop on Dual-Use Research, Teresopolis, Brazi

    Systematics and diversity of Neotropical ants.

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    With a long history of more than 100 million years and about 14,000 described living species, ants are one of the most important and well-known groups of insects in the world. Ants are key elements in the structure and dynamics of terrestrial systems, especially in the tropics, as well as models in studies of evolution, ecology, and monitoring of disturbed ecosystems. For all this, it is essential to know their history and phylogeny, in order among other things, to have a solid base for their systematics and taxonomy. Within Aculeata ants appear to be the sister group of Apoidea, and the ancestor of the Formicidae may have inhabited the northern hemisphere during the early Cretaceous. Since then, and especially since the Eocene, ants have spread throughout the planet, occupying almost all environments from forests to deserts. The Neotropical region has 137 genera and around 3,100 species of ants. The Neotropics seem to have been the “cradle” and “museum” of the groups of ants, which would explain their great diversity and a high degree of endemisms. This review describes the current state of knowledge of ants in the Neotropical region from a systematic point of view, with a synopsis of all supraspecific taxa described to date. Critical genera, problems to be solved, and perspectives for the study of these insects are also presented

    Street lighting energy efficiency

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    Un estudio sobre la optimización de la eficiencia energética en el alumbrado público de la Municipalidad de S. M. de Tucumán fue efectuado basado en la aplicación de relojes astronómicos, balastos electrónicos dimerizables para lámparas de descarga de Sodio de alta presión de 150W/100W y luminarias de alta eficiencia. Durante 45 días, 273 puntos de luz conectados a 6 redes de alumbrado independientes fueron monitoreados, registrando el consumo, tiempos de funcionamiento, apagados nocturnos, encendidos diurnos y parámetros eléctricos de calidad. Los resultados indican que es posible una importante reducción en el consumo, entre un 11% y un 43% mejorando la calidad del servicio y reduciendo el contenido de armónicos que se introducen a la red de alumbrado a TDH A ≤ 6,5%. El trabajo describe la experiencia y el análisis de los resultados obtenidos.A study of street lighting energy efficiency was carried out in S. M. Tucumán City, based on the application of astronomical clocks, electronic ballasts (control gear) for high pressure sodium 150W/100W lamps and high efficiency luminaires. During 45 days, 273 luminaires connected to 6 independent electric networks were monitored recording: energy consumption, switching on/off times, night lamps outages, day on lamps and electrical quality parameters. The results indicate that it is possible a significant reduction in consumption, between 11% and 43% while improving service quality and reducing the harmonic content being introduced to the network lighting by TDH A ≤ 6.5%. The paper describes the experience and the analysis of the results.Fil: Tapia Garzón J.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; ArgentinaFil: Manzano, Eduardo Roberto. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; ArgentinaFil: Gao S.. Municipalidad de S. M. Tucuman - Dirección Alumbrado; ArgentinaFil: Rojas M.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; ArgentinaFil: De Nobrega M.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentin

    A comparative study of the passivation and localized corrosion of α-brass and β-brass in borate buffer solutions containing sodium chloride : III. The effect of temperature

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    The passivation and localized corrosion of α-brass and β-brass in an aqueous borate-boric acid buffer (pH 9) containing different concentrations of NaCl (cNaCl) in the temperature range 5 °C ≤ T ≤ 45 °C were studied comparatively by potential sweeping at 2 × 10−2Vs−1 and 2 × 10−4Vs−1 and de-alloying measurements. The passivation of α-brass and β-brass was related to the electroformation of a complex ZnO · xH2O/Cu2O layer, its thickness and compactness presumably increasing with temperature. For both α-brass and β-brass immersed in an aqueous NaCl-containing buffer, pitting corrosion was observed as the value of the breakdown potential (Eb) was exceeded. At constant temperature, the value of Eb shifted negatively as either cNaCl or the zinc content in the alloy was increased. For β-brass, the value of Eb decreased slightly with increasing temperature in the range 5 °C≤ T ≤45 °C. In the range 5 °C≤ T ≤ 25 °C, for α-brass the value of Eb was close to that reported for copper, whereas for T > 25 °C it approached those values measured for β-brass. De-alloying measurements in aqueous 0.5 M NaCl indicate that zinc surface enrichment of α-brass was responsible for the decrease in pitting corrosion resistance at T > 45 °C.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    Caracterización y clasificación de los carbones cretácicos de Teruel. Relaciones entre sus características y el entorno geológico

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    27 páginas, 8 figuras, 4 tablas.[ES]: Se han caracterizado los carbones cretácicos de la cuenca minera de Teruel (España), mediante el estudio exhaustivo de 36 muestras de capa de todas las explotaciones con actividad minera. El estudio ha comprendido: Análisis inmediato, elemental y petrográfico. Asimismo, se han determinado otros parámetros cuyo conocimiento se consideró necesario. También se han realizado ensayos carboquimicos como oxidación e hidrogenación. Los resultados muestran que aunque estos carbones pertenecen todos a una misma unidad geológica (Formación Escucha), existen diferencias claras entre los carbones de las subzonas Norte y Sur del Distrito Minero. Estos carbones se han clasificado mediante sistemas científicos (Seyler, van Krevelen y Alpem-ICCP) y comerciales (ECE/IJN y ASTM). El mejor parámetro clasificatorio ha sido la reflectividad de la vitrinita. Según el sistema de clasificación utilizado, los carbones de la subzona Norte se pueden considerar como lignitos o subbituminosos B y los de la subzona Sur como subbituminosos B ó A. Las diferencias encontradas entre los carbones estudiados, se explican desde un punto de vista geológico, por dos motivos: 1) Diferente presión litostática sobre las capas de carbón según la subzona, debido al aumento progresivo de la potencia de los sedimentos del Cenomaniense - Senoniense (Cretácico Superior) de Norte a Sur del Distrito Minero. 2) Menor influencia de la orogénesis alpina en las subzona Norte, contrastando con la subzona Sur, donde provocó gran número de fallas y plegamientos (una estructuración más intensa de las sucesiones mesozoicas).[EN]: Cretaceous coals from the Teruel Mining District (Spain) have been characterized by an exhaustive study of 36 bed samples from alí of the underground and upen cut mines with activity in that cual field. This study has included proximate, elemental, petrographic and other analyses. Also, sume chemical tests, as oxidations and hydrogenations, have been carried out. The results show that although these coals belung tu the same geological unit (Escucha Furmation in the lower Cretaceous), there are clear differences between the Norther and Southem Subzones of the Mining District. These coals have been classified by sume scientific (Syler’s, van Krevelen diagram and Alpem-ICCP) and commercial (ECE/UN and ASTM) systems. The best parameter tu classify these coals has been the vitrinite reflectance. In depending un the used classification system, cuaN from the North Subzone can be cunsidered as lignites or subbituminous B while coals from the South Subzone can be considered as subbituminous B or A. The differences between both groups uf studied coals can be explained, from a geological viewpoint, by two major factors: 1) The lithostatic pressure supported by the cual beds has been different in depending un the Subzone, because of the progressive thickness increase of te Cenomanian - Senonian sediments (Upper Cretaceous) from the North tu the South uf the Mining District. 2) The intensity of te Alpine Orogeny was stronger in the South Subzone; where gaye rise tu a more intense structuration of the Mesozoic sequences.El proyecto de investigación: “Caracterización de carbones aragoneses” del que forma parte este proyecto, fue realizado en el Instituto de Carboquímica, gracias a la financiación del CSIC, OCICARBON y Diputación General de Aragón - Diputación Provincial de Teruel (Juan, 1990).Peer reviewe

    Racial and Ethnic Differences in Diabetes Mellitus among People with and without Psychiatric Disorders: Results from the National Epidemiologic Survey on Alcohol and Related Conditions

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    Objective: This study examined racial/ethnic differences in the prevalence of diabetes mellitus in a nationally representative sample of adults with and without common psychiatric disorders. Method: Data were drawn from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (N= 34,653). Logistic regression models adjusting for sociodemographic variables and diabetes risk factors were used to examine racial/ethnic differences in 12-month prevalence rates of diabetes by psychiatric status. Results: Among people without psychiatric disorders, African Americans, Hispanics, and American Indians/Alaska Natives, but not Asians/Pacific Islanders, had significantly higher rates of diabetes than non-Hispanic whites even after adjusting for socio-demographic variables and diabetes risk factors. In the presence of psychiatric disorders, these health disparities persisted for African Americans and Hispanics, but not for American Indians/Alaska Natives. No significant interactions between race/ethnicity and psychiatric disorders in the odds of diabetes were found across any group. Conclusion: Policies and services that support culturally appropriate prevention and treatment strategies are needed to reduce racial/ethnic disparities in diabetes among people with and without psychiatric disabilities

    Stereospecific synthesis of [gamma]-butyrolactones from acyclic vinyl sulfoxides: an asymmetric synthesis of optically pure oak lactones

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    The sulfoxide-directed lactonization of several trisubstituted vinyl sulfoxides with dichloroketene proceeds in a completely stereospecific manner. The lactonization of (E) -3 (R) --tolylsulfinyloctene occurs with complete enantiospecificity to produce a precursor for the synthesis of optically pure oak lactones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25937/1/0000500.pd
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