917 research outputs found

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    Comparing the impacts of drip irrigation by freshwater and reclaimed wastewater on the soil microbial community of two citrus species

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    [SPA] La búsqueda de nuevos recursos para el riego es un requerimiento en los agro ecosistemas mediterráneos. Se evaluó el impacto del riego con aguas de distintos suministros sobre la comunidad microbiana del suelo y sobre la fisiología de la planta en cultivos de pomelo y mandarino en el Sureste de España. Se consideraron los siguientes tratamientos: i) Agua procedente del Trasvase Tajo-Segura y de pozo (TW) ii) Agua regenerada procedente de una EDAR de la zona (RW) iii) Riego con TW, excepto en la segunda fase de desarrollo del fruto en la que se regó con RWc iv) Riego con RW, excepto en la segunda fase de desarrollo del fruto en la que se regó con TWc. [ENG] The search for new water resources for irrigation is a mandatory requirement in Mediterranean agroecosystems. The impacts of irrigation with water from different origins were evaluated in the soil microbial community and plant physiology of grapefruit and mandarin trees in the south-east of Spain. The following treatments were considered: i) freshwater from the Tajo-Segura water transfer canal and well (TW) ii) reclaimed water from a wastewater treatment plant ( RW) iii) irrigation with TW, except in the second stage of fruit development when RWc was applied iv) irrigation with RW, except in the second stage of fruit development when TWc was applied. Enzyme activities and phospholipids fatty acids were determined to know the phylum of microbial biomass.Authors are grateful to MINECO projects and Seneca foundation

    Annotated checklist of marine fishes from the Sanctuary of Bahía Chamela, Mexico with occurrence and biogeographic data.

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    An annotated checklist of marine fishes of the Sanctuary of Islands and Islets of Bahía Chamela in the central Mexican Pacific is presented. Records of fish species were obtained by different methods including visual census, sampling with anesthetics, fisherman-nets, and trawling with a biological dredge. Additional records were obtained from natural history collections and publications. The list comprises 196 species in 64 families and 141 genera. The Carangidae is the most speciose family with 11 species, followed by the Labridae with 10 and the Pomacentridae with nine. Fourteen species are endemic in Mexican Pacific waters, but none is restricted to Bahía Chamela. The most dominant species recorded during underwater surveys were Epinephelus labriformis, Stegastes flavilatus, and Halichoeres dispilus. Most species are of tropical affinities distributed throughout the tropical eastern Pacific (123), eastern Pacific (23), and Mexican Pacific (14). Other species are known from the eastern and Indo-Pacific regions (18), eastern Pacific and western Atlantic oceans (2), and some are circumtropical (9). A new record of the Gulf Brotula Ogilbia ventralis is provided for the Bahía Chamela and its geographical distribution is extended to Mexican central Pacific

    Macroscopic evidence of microscopic dynamics in the Fermi-Pasta-Ulam oscillator chain from nonlinear time series analysis

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    The problem of detecting specific features of microscopic dynamics in the macroscopic behavior of a many-degrees-of-freedom system is investigated by analyzing the position and momentum time series of a heavy impurity embedded in a chain of nearest-neighbor anharmonic Fermi-Pasta-Ulam oscillators. Results obtained in a previous work [M. Romero-Bastida, Phys. Rev. E {\bf69}, 056204 (2004)] suggest that the impurity does not contribute significantly to the dynamics of the chain and can be considered as a probe for the dynamics of the system to which the impurity is coupled. The (r,τr,\tau) entropy, which measures the amount of information generated by unit time at different scales τ\tau of time and rr of the observable, is numerically computed by methods of nonlinear time-series analysis using the position and momentum signals of the heavy impurity for various values of the energy density ϵ\epsilon (energy per degree of freedom) of the system and some values of the impurity mass MM. Results obtained from these two time series are compared and discussed.Comment: 7 pages, 5 figures, RevTeX4 PRE format; to be published in Phys. Rev.

    Epistemología, caos y enseñanza de las ciencias

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    In this article it is maintained that modern science is going through a critical period where its epistemological assumptions and the use of a parcelling and reductionist methodology are questioned. This will surely have important implications in the teaching of the sciences, perhaps because the world today demands above all an epistemological change in the people who, within a few years, will occuppy the posts in the production and reproduction of scientific and technical knowledge

    The response of taxonomic and functional diversity of the seed bank to agricultural intensification and soil properties in two Mediterranean cereal areas

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    Weed seed bank diversity has been severely impacted by agriculture intensifi cation. However, the functional consequences have been poorly studied in highly intensifi ed agro-ecosystems.Postprint (published version

    In memoriam of Andrés Pérez-Estaún

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    Ecología, biología reproductiva y conservación de Picris willkommii (Schultz Bip.) Nyman (Asteraceae): endemismo protegido integrado en pastos terofíticos del suroeste de la Península Ibérica

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    Current knowledge of the biology of Picris willkommii and his grade of threat, seem not to be sufficient to ensure longterm persistence of this plant species endemic to the South-Western Iberian Peninsula. In Spain, main populations of the species are narrowly restricted to therophytic grasslands around the town of Ayamonte, by the Guadiana river drainage. Results of the present study indicate that P. willkommii behaves as a very versatile, colonizing species in most of the habitats of their natural range, where it appears to be well suited to the cyclic disturbance dynamics imposed by local, traditional land uses, i.e. extensive rain-fed agriculture. Moreover, it is easy to grow under controlled conditions. Results could be helpful for conservation and population recovery purposes, as recent changes in land use, shifting from agricultural traditional systems to urban expansion or alternative agricultural systems, pose at risk P. willkommii populations due to habitat loss.Los conocimientos actuales sobre Picris willkommii y su grado de amenaza, parecen insuficientes para garantizar la persistencia de esta especie endémica del suroeste de la Península Ibérica, con sus poblaciones principales conocidas en España restringidas a pastos terofíticos muy localizados en las proximidades de la localidad de Ayamonte (desembocadura del río Guadiana). Los resultados obtenidos en el presente trabajo revelan a la especie como ruderal muy versátil, colonizadora, bien adaptada y en equilibrio dependiente de la dinámica cíclica de los aprovechamientos agropecuarios seculares de la zona, siendo además de fácil cultivo bajo condiciones controladas. Estos datos podrían resultar de utilidad para el establecimiento de estrategias dirigidas a la conservación y recuperación de la especie, ya que los cambios de uso observados en la zona por abandono de estos sistemas cíclicos de secano, y su rápida urbanización o sustitución por otros sistemas de producción, están suponiendo eliminación sensible de las poblaciones de la especie por la desaparición de los pastos de los que forma parte

    On maximum entropy priors and a most likely likelihood in auditing

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    There are two basic questions auditors and accountants must consider when developing test and estimation applications using Bayes' Theorem: What prior probability function should be used and what likelihood function should be used. In this paper we propose to use a maximum entropy prior probability function MEP with the most likely likelihood function MLL in the Quasi-Bayesian QB model introduced by McCray (1984). It is defined on an adequate parameter. Thus procedure only needs an expected value of θ0 known (in this paper the expected tainting) to obtain a MEP all an auditor or accountant need to supply are the range, as with any other prior, and the expected tainting, θ0. We will see some practical applications of the methodology proposed about internal control evaluation in auditing

    A Nori but not a Konbu, dietary supplement decreases the cholesterolaemia, liver fat infiltration and mineral bioavailability in hypercholesterolaemic growing Wistar rats

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    The nutritional consequences of algae consumption in young populations consuming hypercholesterolaemic diets have hardly been investigated. This study tests the effect of algae supplementation of cholesterol-enriched balanced diets on growth, dietary efficiency ratio, mineral intake and absorption, organ weight and structure and cholesterolaemia in growing Wistar rats. Three groups of ten rats each were fed for 3 weeks with experimental diets containing 93% casein-soyabean oil base with 2.4% cholesterol-raising agent and 7% supplement. The control group received cellulose (35%), group 2 consumed Nori (33.8% fibre) and group 3 consumed Konbu (36.1% fibre). Food intake and body weight gain were not significantly affected. Algae groups presented significantly higher dietary efficiency ratio values than control rats. Apparent absorption of several minerals appeared significantly affected, mainly in Nori-fed rats, with a significant decrease in the ratio of Zn and Cu intakes and apparent absorption. Nori diet significantly decreased plasma cholesterol. Algae supplement did not significantly affect organ size and structure. Control and Konbu rats showed severe liver fat infiltration, while Nori rats exhibited a significantly lower degree of lipid-like hepatocyte vacuolization but light to moderate leukocyte infiltration. Light to moderate scaling off of the epithelium and moderate submucosa oedema was observed in all groups. Although long-term studies are needed to check the possible extrapolation of these data to human subjects, it can be concluded that a Nori, but not a Konbu, dietary supplement reverses the negative effect of dietary cholesterol intake and also appears to be related to mineral availability in growing subjects. © 2007 The Authors.This work was granted by the Spanish Ministerio de Investigación y Ciencia, Project AGL 2005-07204-C02-C1/ALI.Peer Reviewe
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