3,102 research outputs found

    Erupciones hidromagmáticas en el borde occidental del Macizo de Calatrava. Campo de Calatrava (España). El volcán del Rinconcillo

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    [Resumen] El Macizo de Calatrava es un apretado conjunto de sierras y ordovícicas, situado al sureste del Campo de Calatrava, intensamente fracturado y limitado por bordes de fosa tectónica El volcanismo que en él se desarrolla se caracteriza por la presencia de dinámicas eruptivas de alta y baja explosividad, predominando las erupciones de carácter hidromagmático, sobre cualquier otra. Las formas de relieve originadas en estas erupciones, son las que de manera más rotunda han modificado el paisaje, al abrirse amplias, profundas y numerosas depresiones explosivas, comúnmente ocupadas por láminas de agua de carácter estacional. Los depósitos pertenecientes a oleadas piroclásticas basales, tienen una gran extensión superficial[Abstract] The Calatrava Massif, is a compact ensemble of ridges of the Ordovician period, located into SW in the Campo de Calatrava. This Massif, is intensely broken and limited by tectonic graben. The volcanic activity develops strombolian and phreatic emptions with prevalence of last ones. The landforms generated by these eruptions, have modified the landscapes to open, wide, deep and numerous explosives craters, commonly occupied by occasional water. The basal surge"s deposits occupy a wide extension

    Adaptation, Compatibility and Acceptability of Grass-Legume Pastures in the Andean Region of Colombia

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    In Colombia, the specialised dairy production system is located in the high altitude Andean region. Its main feed resources are pure stands of Pennisetum clandestinum or/and Lolium spp. Nevertheless, the present market conditions require highly competitive and quality forages year round. These forages should be produced with low inputs (irrigation, fertilisers and agrochemicals) and be resistant to pests and diseases. The objective of this research was to evaluate the adaptation, compatibility and acceptability of introduced forage species for sustainable pasture management

    Atomic Effective Pseudopotentials for Semiconductors

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    We derive an analytic connection between the screened self-consistent effective potential from density functional theory (DFT) and atomic effective pseudopotentials (AEPs). The motivation to derive AEPs is to address structures with thousands to hundred thousand atoms, as given in most nanostructures. The use of AEPs allows to bypass a self-consistent procedure and to address eigenstates around a certain region of the spectrum (e.g., around the band gap). The bulk AEP construction requires two simple DFT calculations of slightly deformed elongated cells. The ensuing AEPs are given on a fine reciprocal space grid, including the small reciprocal vector components, are free of parameters, and involve no fitting procedure. We further show how to connect the AEPs of different bulk materials, which is necessary to obtain accurate band offsets. We derive a total of 20 AEPs for III-V, II-VI and group IV semiconductors and demonstrate their accuracy and transferability by comparison to DFT calculations of strained bulk structures, quantum wells with varying thickness, and semiconductor alloys.Comment: 10 pages, 5 figures, submitted to PR

    Degree of Quantumness in Quantum Synchronization

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    We introduce the concept of degree of quantumness in quantum synchronization, a measure of the quantum nature of synchronization in quantum systems. Following techniques from quantum information, we propose the number of non-commuting observables that synchronize as a measure of quantumness. This figure of merit is compatible with already existing synchronization measurements, and it captures different physical properties. We illustrate it in a quantum system consisting of two weakly interacting cavity-qubit systems, which are coupled via the exchange of bosonic excitations between the cavities. Moreover, we study the synchronization of the expectation values of the Pauli operators and we propose a feasible superconducting circuit setup. Finally, we discuss the degree of quantumness in the synchronization between two quantum van der Pol oscillators

    Sustainable Pastures for the High Altitude Andean Tropics of Colombia

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    Dairy production systems in the high altitude Andean region of Colombia (\u3e2.600 m.a.s.l.) use large amounts of nitrogen (N) fertilisation. Due to the inefficient use of N by the grass, it contaminates surface and ground water resulting in the eutrophication of lakes and rivers. It contributes to increased atmospheric NOx, greenhouse gas and acid rain. Therefore, the effect of different species of grasses mixed with Lotus corniculatuson N soil balance was evaluated

    Natural Compounds as an Alternative to Control Farm Diseases: Avian Coccidiosis

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    Coccidiosis is one of the most aggressive and expensive parasite diseases in poultry industry worldwide. Currently, the most used control techniques are chemoprophylaxis and anticoccidial feed additives. Although there is a great variety of commercial anticoccidial drugs and vaccines in the market, there is also a significant resistance to use them in animals with human as final consumer. To date, none available product offers effective protection toward coccidiosis; however, the search for novel strategies to control this disease continues, and natural products have arisen as a potential way to cope with avian coccidiosis. In this chapter, we highlight recent advances in natural compounds, their anticoccidial properties, and mechanisms

    Whitefly-transmitted viruses

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    Whiteflies (Homoptera) are well known for their capacity to transmit 28 plant viruses of beans and other crops. Whitefly populations are generally restricted to tropical zones with alt. greater than 1300 m. Among the viruses transmitted there are: (1) BGMV is an economically important disease especially in regions of L.A., some parts of Central America and the Caribbean. Symptoms are clearly visible; the leaves take on a brilliant yellow or golden color. The virus can be transmitted artificially by inoculation. Diseases incidence can be reduced by eliminating alternative plant reservoirs of inoculum with crop rotation. Planting date should be Programmed so that young plants develop during periods of low temp and high moisture. Whiteflies can be controlled economically, applying insecticides in order to reduce the vector population and incidence of BGMV transmission. Plant resistance is an economical method of control. (2) Bean chlorotic mottle virus produces severe dwarfing of susceptible plants, accompanied by a high proliferation of buds and a bunchy or rosette type of plant development. (3) Euphorbia mosaic virus produces necrotic leaf lesions at feeding sites of whiteflies. (4) Rhynchosia mosaic virus includes a wide host range, causes leaf malformation, yellowing, witches'-broom and plant stunting in young plants. The symptoms and damage caused by the viruses are illustrated in color. (CIAT)Las moscas blancas (Homoptera) son ampliamente conocidas por su capacidad de transmitir 28 virus del frijol y otros cultivos. Las poblaciones de moscas blancas estan generalmente restringidas a las zonas tropicales con una alt. menor que 1300 m. Entre los virus transmitidos se destacan: 1) El BGMV es una enfermedad de importancia economica especialmente en las regiones de America Latina, algunas partes de America Central y el Caribe. Los sintomas son claramente visibles; las hojas toman un color amarillo brillante o dorado. El virus se puede transmitir artificialmente mediante inoculacion. La incidencia de la enfermedad se puede reducir mediante la eliminacion de fuentes alternas del inoculo con rotacion de cultivos. La fecha de siembra se debe programar para que las plantas jovenes se desarrollen durante los periodos de bajas temperaturas y alta humedad. La mosca blanca se puede controlar economicamente mediante la aplicacion de insecticidas, con el fin de disminuir las poblaciones del vector y la incidencia de la transmision del BGMV. La resistencia de la planta constituye un metodo de control economico. 2) El virus del moteado clorotico del frijol produce enanismo severo en las plantas susceptibles, junto con una gran proliferacion de yemas y un desarrollo de la planta en forma de racimo o roseta. 3) El virus del mosaico de las euforbiaceas produce lesiones necroticas en las hojas en los sitios de alimentacion de las moscas blancas. 4) El virus del mosaico de la Rhynchosia incluye un amplio rango de hospedantes, ocasiona deformacion y amarillamiento de las hojas, superbrotamiento y raquitismo de las planta jovenes. Se ilustran en color los sintomas y el dano causado por los virus. (CIAT

    Inflation as a response to protect the Holographic Principle

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    A model where the inflationary phase emerges as a response to protect the Fischler-Susskind holographic bound is described. A two fluid model in a closed universe inflation picture is assumed, and a discussion on conditions under which is possible to obtain an additional exponential expansion phase as those currently observed is given.Comment: 6 pages, 2 figures. Accepted for publication in MPL
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