1,309 research outputs found

    En torno al imperfecto con valor de futuro hipotético

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    Este trabajo pretende presentar los rasgos de funcionamiento de un conjunto de valores discursivos del imperfecto de indicativo, especialmente vivos en el español hablado, en los cuales esta forma del pasado ostenta valores análogos a los que tiene la forma cantaría como futuro hipotético dentro del entramado del sistema verbal español. Comenzamos describiendo de modo esquemático la situación del imperfecto en el sistema verbal español, por un lado, y sus principales valores discursivos, para acercarnos más tarde a los valores del futuro hipotético en los que coincide el uso del imperfecto en español hablado y dentro de contextos cuya modalidad es desiderativa o condicional

    Gramáticas y diccionarios en la enseñanza del español como L2: pasado, presente y futuro

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    Tectono-sedimentary evolution of the San Pedro basin (Dominican Republic) and its hydrocarbon potential

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    Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Geológicas, leída el 16-12-2020La Cuenca de San Pedro (CSP) se define como una depresión batimétrica con tendencia E-O y una extensión aproximada de 6000 km2, situada en el margen sureste de la isla de La Española (República Dominicana y Haití). Estructuralmente, el SPB está ubicada en la parte trasera del Cinturón Deformado de los Muertos (CDM). Considerada tradicionalmente como una cuenca de edad Mioceno medio, cuyo relleno ha sido depositado en el espacio de configuración generado por la progresiva deformación del CDM. El área de estudio pertenece al límite norte entre las Placas Norteamericana y Caribe, habiendo registrado la compleja interacción entre ambas. Aun-que la CSP se encuentra próxima a un sistema petrolero confirmado (los descubrimientos de Ma-leno e Higuerito en la región de Azua recuperaron 50,000 brls de petróleo), podría considerarse como poco explorada y los diferentes intentos de correlaciones estructurales y estratigráficas con la región de San Cristóbal (tradicionalmente considerada como la extensión en tierra de la CSP) y la cuenca de Azua han puesto de manifiesto importantes discrepancias. En consecuencia, tanto la evolución de la CSP como su potencial de hidrocarburos siguen sin estar claramente definidos...The San Pedro Basin (SPB) consists of an E-W bathymetric depression with an extension of 6000 km2, located in the south-eastern margin of Hispaniola Island (Dominican Republic and Haiti). Structurally, the SPB is situated at the rear zone of the Muertos Thrust Belt (MTB). The basin has been dated as middle Miocene in the bibliography, with the infill deposited in the configuration space generated by the progressive deformation of the MTB. The study area belongs to the north-ern limit of the Caribbean Plate, having recorded the complex interaction with the North Ameri-can Plate. Although the SPB is located close to a confirmed petroleum system (the discoveries of Maleno and Higuerito in the Azua region recovered 50,000 brls of oil), it remains almost unex-plored and the different attempts of onshore-offshore structural and stratigraphic correlations with the nearby San Cristóbal (traditionally considered as the onshore extension of SPB) and Azua Basins have shown strong discrepancies. Therefore, the SPB evolution and its hydrocarbon po-tential remains unclear...Fac. de Ciencias GeológicasTRUEunpu

    Epicuticular Wax Load of Near-Isogenic Barley Lines Differing in Glaucousness

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    Scanning electron microscopy observations of epicuticular waxes on flag leaves (blades and sheaths) and ears were carried out on a pair of near-isogenic lines of two-row barley (Hordeum vulgare L. ), derived from cv. Troubadour, differing in their degree of glaucousness (wax bloom). Plants were grown under irrigated and rainfed mediterranean conditions. Wax bloom in flag leaves consisted mainly of thin wax deposits over the blade, and tubes over the sheath. Wax bloom in the blade was denser and more uniformly arranged on the adaxial than on the abaxial side. In the ears, tubular waxes predominated, forming dense patches on awns and lemmas, and becoming sparse on inner bracts such as the palea. Wax bloom increased under rainfed conditions in both lines. There were marked differences between the lines in the extent of deposition of crystallized epicuticular waxes in the leaf sheath and the ear, whereas differences in the leaf blade were less evident. Wax bloom was almost absent on the sheaths and ear of the non-glaucous line. These results suggest separate genetic control of epicuticular wax deposition on different parts of barley plants. The role of wax bloom in two related ecophysiological parameters, canopy reflectance and cuticular conductance to water diffusion, was also studied. Reflectance by the canopy in the 400 to 700 nm wavelengths was over 50% higher in the glaucous than in the non-glaucous line under rainfed conditions. Under irrigated conditions, flag leaf blades of the non-glaucous line showed the highest epidermal conductance. Ears showed no clear differences in epidermal conductance between lines or growth conditions

    Sustainable agriculture as a central science to solve global society issues

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    Serious global issues such as poverty, illness, food prices, climate changes, global market, pollution, pest adaptation and resistance, soil degradation, decreasing biodiversity and desertification can be explained by the increasing artificialization of human society. Since most issues are now intertwined they cannot be solved anymore by the classical fireman approach. In that respect, the structure of actual science and governmental institutions are probably outdated and should evolve to meet global challenges. Unexpectedly, agronomy appears as a central science to solve current societal issues because agronomists are trained to manage the input of many disciplines such as plant biology, soil science, climate sciences, ecology and chemistry

    Breeding to Optimize Agriculture in a Changing World

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    AbstractBreeding to Optimize Chinese Agriculture (OPTICHINA) was a three-year EU–China project launched in June of 2011. As designed, the project acted as a new strategic model to reinforce systematic cooperation on agricultural research between Europe and China. The OPTICHINA International Conference “Breeding to Optimize Agriculture in a Changing World” was held in Beijing, May 26–29, 2014. The conference included six thematic areas: (1) defining and protecting the yield potential of traits and genes; (2) high-throughput precision phenotyping in the field; (3) molecular technologies in modern breeding; (4) plant ideotype; (5) data analysis, data management, and bioinformatics; and (6) national challenges and opportunities for China. The 10 articles collected in this special issue represent key contributions and topics of this conference. This editorial provides a brief introduction to the OPTICHINA project, followed by the main scientific points of articles published in this special issue. Finally, outcomes from a brainstorming discussion at the end of the conference are summarized, representing the authors' opinions on trends in breeding for a changing world

    Water and nitrogen conditions affect the relationships of Δ13C and Δ18O to gas exchange and growth in durum wheat

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    Whereas the effects of water and nitrogen (N) on plant Δ13C have been reported previously, these factors have scarcely been studied for Δ18O. Here the combined effect of different water and N regimes on Δ13C, Δ18O, gas exchange, water-use efficiency (WUE), and growth of four genotypes of durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] cultured in pots was studied. Water and N supply significantly increased plant growth. However, a reduction in water supply did not lead to a significant decrease in gas exchange parameters, and consequently Δ13C was only slightly modified by water input. Conversely, N fertilizer significantly decreased Δ13C. On the other hand, water supply decreased Δ18O values, whereas N did not affect this parameter. Δ18O variation was mainly determined by the amount of transpired water throughout plant growth (Tcum), whereas Δ13C variation was explained in part by a combination of leaf N and stomatal conductance (gs). Even though the four genotypes showed significant differences in cumulative transpiration rates and biomass, this was not translated into significant differences in Δ18Os. However, genotypic differences in Δ13C were observed. Moreover, ∼80% of the variation in biomass across growing conditions and genotypes was explained by a combination of both isotopes, with Δ18O alone accounting for ∼50%. This illustrates the usefulness of combining Δ18O and Δ13C in order to assess differences in plant growth and total transpiration, and also to provide a time-integrated record of the photosynthetic and evaporative performance of the plant during the course of crop growth
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