1,188 research outputs found

    Economic Efficiency and Growth: Evidence from Brazil, China, and India

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    We compare economic efficiencies in Brazil, India, and China, where economic efficiency measures the gap between potential and actual output for a given input combination and technological factor. We use stochastic production frontier models to measure the contributions of factors of production and technology to growth and estimate non-positive error terms that capture production inefficiencies in each country. The results suggest that China and India had relatively inefficient production in the early 1980s but have since improved production efficiency substantially. In the same period, production efficiency in Brazil has declined somewhat from relatively high initial levels and the gap between production efficiency between these countries has narrowed substantially, supporting more rapid growth in China and India relative to Brazil.growth, trade, production

    An investigation of public and private R&D partnership

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    16th Annual Meeting of the Academy of Management, Toronto, Ontario, Canada, August 2000 : A New TimeIn this paper we investigate public and private research and development relationships with respect to their performance. The study utilizes a database of over 250 of these relationships, funded by Spanish government agencies. The methodology includes the application of data envelopment analysis (DEA) to determine the relative performance ("efficiency") of the various projects

    Foliar nutrient levels of native tree species from Central Amazonia. I. Inundation forests

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    The study of the leaf size spectra and foliar concentrations of N, P, K, Ca, Mg and Na of 52 species sampled in three Central-Amazon inundation forests (2 várzea sites, 1 igapó site) yielded signifìcant differences between várzea and igapó forests. The várzea foliage consists of larger and less heavy leaves with elemental concentrations being high even by tropical standards. The igapó foliage consists of relatively small leaves which are heavier, but much lower in the studied elements. The igapó leaves are supposed to be sclerophyllous and evergreen

    Factores ambientales condicionantes de la presencia de la lagartija de Carbonell Podarcis carbonelli (Pérez-Mellado, 1981) en la comarca de Doñana

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    The Carbonell lizard (Podarcis carbonelli) is an Iberian endemism. The region of Doñana is its southernmost and more isolated stronghold. We used logistic regressions to investigate the factors conditioning the presence of this lizard in Doñana. All selected models retained the distance to the coast as the main variable. This variable is related with less humidity and more continental climatic conditions, including more extreme temperatures, when further from the coast. This climatic factor was observed both spatially and temporarily, with adult lizards drastically reducing their activity both in winter and in summer. We observed juveniles from June to January, with a maximum in September. Scrubland management was another important environmental factor affecting the presence of lizards. The probability of finding this species was higher where the scrubland was partially cleared, and lower in areas with a high plant cover (hygrophytic scrubland) or in areas with sparse vegetation (dune scrubland), probably due to a lower amount of incident light and less protection when moving between refuges, respectively.La lagartija de Carbonell es un endemismo ibérico que encuentra en la comarca de Doñana el reducto más meridional y aislado de su área de distribución. Mediante el uso de regresiones logísticas se ha intentado conocer qué factores condicionan la presencia de la lagartija de Carbonell en Doñana. La variable principal de los distintos modelos fue la distancia a la costa. Ésta se relaciona con un menor grado de humedad y una mayor continentalidad del clima, con temperaturas más extremas, a medida que nos alejamos del mar. Este condicionante climático se ha observado tanto espacial como temporalmente, reduciéndose drásticamente la actividad de los animales adultos en verano e invierno. Los juveniles se observan desde junio a enero con un máximo en septiembre. Otro de los factores importantes ha resultado ser la gestión del matorral. Se ha observado una mayor probabilidad de encontrar la lagartija de Carbonell en zonas en las que el matorral ha sido parcialmente clareado, ya que evita los lugares con elevadas densidades de plantas (matorral hidrofílico), que reducirían el paso de la luz, o con una densidad muy baja (matorral de las dunas), que no permitiría el tránsito seguro entre refugios

    Evaluación de pastas de Hesperaloe funifera obtenidas con un proceso de bajo consumo energético como material de refuerzo de pastas recicladas

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    The aim of this work is to study the reinforcement capacity of pulps obtained from Hesperaloe funifera using a simple and low energy consumption process (chemi refiner mechanical pulping) once they are added in different percentages to recycled pulps from newspaper and from old corrugated containers (OCC). Pinus radiata kraft pulp was used as a referent reinforcement material. H. funifera acted as a reinforcement material in newspaper and OCC recycled pulps, improving their optical and mechanical properties. While a 25% of H. funifera was the optimal amount added to reinforce the OCC pulp, only a 10% was needed for newspaper pulp. However, the OCC optimal mixture was better reinforced as it showed higher increase in all properties than the optimal newspaper mixture, apart from tensile index. Finally, all mixtures with P. radiata kraft pulp produce handsheet with lower properties, apart from tear index, suggesting than H. funifera is a better reinforcement material.El objetivo de este trabajo es estudiar la capacidad de refuerzo de pastas de Hesperaloe funifera obtenidas mediante un proceso simple de bajo consumo energético (pasteado químico-mecánico de refino) una vez añadidas en diferentes porcentajes a pastas recicladas de periódicos y de cartón ondulado (OCC). Se utilizó como material de refuerzo de referencia pasta kraft de Pinus radiata. H. funifera mejoró las propiedades ópticas y mecánicas de todas las pastas recicladas estudiadas, demostrando su capacidad de refuerzo. Mientras que un 25% de H. funifera fue la cantidad óptima para reforzar la pasta de OCC, sólo un 10% fue necesario para la pasta de periódicos. Sin embargo, la mezcla óptima de OCC mostró un mayor incremento en todas las propiedades que la mezcla óptima de periódicos, a excepción del índice de tracción. Por último, todas las mezclas de pasta kraft de P. radiata proporcionaron hojas con menores propiedades mecánicas, a excepción del índice de desgarro, lo que sugiere que H. funifera es un material de refuerzo más eficaz

    Impact of the application of monosilicic acid to grapevine (Vitis vinifera L.) on the chemical composition of young red Mencia wines

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    Impact of applying monosilicic acid to grapevines during ripening on chemical composition of Mencía red wines in an area where fungal diseases during summer are common was examined. The foliar application of monosilicic acid to grapevines led to a less oxidized wine, with lower levels of acetic acid, acetaldehyde, ethyl acetate and diacethyl; this should be considered as positive from a sensory point of view. Wines made with silicon-treated grapes also contained lower levels of gluconic acid and glycerol, which are chemical markers of wines made with botrytized grapes, as well as higher contents of total phenols, anthocyanins and tannins. Furthermore, the contents of several mid-chain alcohols were higher (p < 0.05) in wines made with grapes from silicon-treated plantsThe authors gratefully acknowledge the financial support by the FEDER/Spanish Ministry of Science, Innovation, and Universities Project: RTI2018-096268-B-I00. This work was partially supported by Comunidad de Madrid (Spain) and Structural Funds 2014–2020 (ERDF and ESF) (Project AGRISOST-CM S2018/BAA-4330

    Resonance fluorescence spectrum of a \Lambda-type quantum emitter close to a metallic nanoparticle

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    We theoretically study the resonance fluorescence spectrum of a three-level quantum emitter coupled to a spherical metallic nanoparticle. We consider the case that the quantum emitter is driven by a single laser field along one of the optical transitions. We show that the development of the spectrum depends on the relative orientation of the dipole moments of the optical transitions in relation to the metal nanoparticle. In addition, we demonstrate that the location and width of the peaks in the spectrum are strongly modified by the exciton-plasmon coupling and the laser detuning, allowing to achieve controlled strongly subnatural spectral line. A strong antibunching of the fluorescent photons along the undriven transition is also obtained. Our results may be used for creating a tunable source of photons which could be used for a probabilistic entanglement scheme in the field of quantum information processing

    Bacterial Biohybrid Microswimmers

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    Over millions of years, Nature has optimized the motion of biological systems at the micro and nanoscales. Motor proteins to motile single cells have managed to overcome Brownian motion and solve several challenges that arise at low Reynolds numbers. In this review, we will briefly describe naturally motile systems and their strategies to move, starting with a general introduction that surveys a broad range of developments, followed by an overview about the physical laws and parameters that govern and limit motion at the microscale. We characterize some of the classes of biological microswimmers that have arisen in the course of evolution, as well as the hybrid structures that have been constructed based on these, ranging from Montemagno's ATPase motor to the SpermBot. Thereafter, we maintain our focus on bacteria and their biohybrids. We introduce the inherent properties of bacteria as a natural microswimmer and explain the different principles bacteria use for their motion. We then elucidate different strategies that have been employed for the coupling of a variety of artificial microobjects to the bacterial surface, and evaluate the different effects the coupled objects have on the motion of the 'biohybrid.' Concluding, we give a short overview and a realistic evaluation of proposed applications in the field

    On the absence of acylated anthocyanins in some wild grapevine accessions

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    Our current research is focused on the anthocyanin composition of female grape accessions, mostly Spanish, preserved at El Encín Germplasm Bank. In 2008, berries of 126 accessions were taken at maturity. After the extraction from grape skins, total anthocyans were determined by spectrophotometry, and the anthocyanin fingerprint of grapes by HPLC, considering the relative amount of 15 anthocyanins. Among those 126 accessions, 23 genotypes (18.25 %) did not present acylated anthocyanins. Thus, those 23 genotypes presented a characteristic anthocyanin fingerprint, similar at a certain extent to that presented by some Rhine basin and Italian grape cultivars, e.g., 'Pinot Noir' and 'Gaglioppo'. Nevertheless, the absence of acylated anthocyanins has not been described in any Spanish grape cultivar. The examination of the anthocyanin fingerprint of wild grapes without acylated anthocyanins reveals that the regulation of the anthocyanin biosynthesis may differ in various wild grape accessions.
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