391 research outputs found

    Evaluación de suelos de "El Condado" Huelva

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    91 páginas.-- 1 figura.-- 15 tablas.-- 20 fotos de suelos y perfiles de suelos.-- 15 referencias.-- Memoria ppresentada en el XXIV Curso Internacional de Edafología y Biología VegetalEl presente estudio, consiste en la evaluación de suelos, respecto al estudio básico a nivel de reconocimiento de la zona de El Condado perteneciente a la provincia de Huelva, que fue realizado como parte aplicada del XXII y XXIII Curso Internacional de Edafología y Biología Vegetal; sin embargo en esta oportunidad, dicha evaluación, es parte del XXIV Curso Internacional ya antes mencionado, lo cual contempla las áreas de la Palma del Condado hoja topográfica nº 982 y Moguer hoja topográfica nº 1000 respectivamente. El trabajo se desarrolló en cinco etapas principales; la primera o de gabinete (Pre-campo), que se hizo por medio de revisión y análisis de toda la información existente (Documento Base de reconocimiento escala 1:50.000, fotografías aéreas escala 1:40.000 de fecha 1984; mapas topográficos y geológicos escala 1:50.000 etc.). Luego con base a la información anterior, fue necesario una segunda etapa, consistente en la visita de campo (observación ocular), teniendo como fin, ampliar la visión o criterio del área geomorfológicamente y retroalimentar el gabinete inicial, lo cual ya con ' estas dos etapas fundamentales, se realizó una tercera, que nuevamente contempló el gabinete para hacerlos reajustes necesarios, dando como resultado, la conveniencia de hacer una segunda y última salida al campo, que luego. como etapa final de gabinete y con los resultados analíticos de laboratorio se hicieron las interpretaciones requeridas. También se realizaron otras etapas, como redacción, impresión y por consiguiente el documento final. El área estudiada, está situada en la Provincia de Huelva; comprende una extensión de 108.584 Has. Su ubicación geográfica se encuentra entre los paralelos 37º 10' 04" y 37º 30' 04" latitud norte y 6º 31' l0" y 6º 51' l0" de longitud oeste de Greenwich.Patrocinado por la UNESCO, Instituto de Cooperación Iberoamericana, Consejo Superior de Investigaciones CientíficasPeer reviewe

    Caractérisation et modélisation des phénomènes de vieillissement dans les alliages de zirconium

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    International audienceDe nombreuses manifestations mécaniques de phénomènes de vieillissement (interactions dislocations-atomes de soluté) dans le domaine de températures 20°C-600°C ont été observées dans les alliages de zirconium [1]. L'influence systématique des éléments d'addition (oxygène, niobium) et la caractérisation précise du domaine de vieillissement restent toutefois mal connues. Dans cette étude, de nouveaux alliages de zirconium ont été spécialement élaborés à partir d'une barre de zirconium 2.2% hafnium à faible teneur en oxygène (80 ppm), puis caractérisés par différents essais mécaniques. Les phénomènes de vieillissement dynamique observés sont associés à des valeurs faiblement positives de sensibilité de la contrainte à la vitesse de déformation. Ces phénomènes ont ensuite été modélisés pour l'alliage de référence nommé Zr702 (sens travers) à forte teneur en oxygène (1300 ppm): creux de sensibilité de la contrainte à la vitesse de déformation autour de 300°C, arrêt de fluage et de relaxation à 200°C et 300°C et hétérogénéités de déformation plastique en traction le long du fût de l'éprouvette. Le modèle de comportement utilisé en éléments finis est fondé sur le modèle phénoménologique de vieillissement dynamique proposé par MacCormick [2], [3], validé sur des alliages d'aluminium et des aciers [4], [5], [6] et appliqué ici à l'alliage Zr702 dans le domaine de températures 20°C-400°C [7]

    On the origin and application of the Bruggeman Correlation for analysing transport phenomena in electrochemical systems

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    The widely used Bruggeman equations correlate tortuosity factors of porous media with their porosity. Finding diverse application from optics to bubble formation, it received considerable attention in fuel cell and battery research, recently. The ability to estimate tortuous mass transport resistance based on porosity alone is attractive, because direct access to the tortuosity factors is notoriously difficult. The correlation, however, has limitations, which are not widely appreciated owing to the limited accessibility of the original manuscript. We retrace Bruggemans derivation, together with its initial assumptions, and comment on validity and limitations apparent from the original work to offer some guidance on its use.<br/

    Developing a community-based intervention to improve quality of life in people with colorectal cancer: a complex intervention development study

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    Objectives: To develop and pilot a theory and evidence-based intervention to improve quality of life (QoL) in people with colorectal cancer. Design: A complex intervention development study. Setting: North East Scotland and Glasgow. Participants: Semistructured interviews with people with colorectal cancer (n=28), cancer specialists (n=16) and primary care health professionals (n=14) and pilot testing with patients (n=12). Interventions: A single, 1 h nurse home visit 6–12 weeks after diagnosis, and telephone follow-up 1 week later (with a view to ongoing follow-up in future). Primary and secondary outcome measures: Qualitative assessment of intervention feasibility and acceptability. Results: Modifiable predictors of QoL identified previously were symptoms (fatigue, pain, diarrhoea, shortness of breath, insomnia, anorexia/cachexia, poor psychological well-being, sexual problems) and impaired activities. To modify these symptoms and activities, an intervention based on Control Theory was developed to help participants identify personally important symptoms and activities; set appropriate goals; use action planning to progress towards goals; self-monitor progress and identify (and tackle) barriers limiting progress. Interview responses were generally favourable and included recommendations about timing and style of delivery that were incorporated into the intervention. The pilot study demonstrated the feasibility of intervention delivery. Conclusions: Through multidisciplinary collaboration, a theory-based, acceptable and feasible intervention to improve QoL in colorectal cancer patients was developed, and can now be evaluated

    A General Relativistic Rotating Evolutionary Universe - Part II

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    As a sequel to (Berman, 2008a), we show that the rotation of the Universe can be dealt by generalised Gaussian metrics, defined in this paper. Robertson-Walker's metric has been employed with proper-time, in its standard applications; the generalised Gaussian metric imply in the use of a non-constant temporal metric coefficient modifying Robertson-Walker's standard form. Experimental predictions are madeComment: 7 pages including front cover. Publishe

    Coincident brane nucleation and the neutralization of \Lambda

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    Nucleation of branes by a four-form field has recently been considered in string motivated scenarios for the neutralization of the cosmological constant. An interesting question in this context is whether the nucleation of stacks of coincident branes is possible, and if so, at what rate does it proceed. Feng et al. have suggested that, at high ambient de Sitter temperature, the rate may be strongly enhanced, due to large degeneracy factors associated with the number of light species living on the worldsheet. This might facilitate the quick relaxation from a large effective cosmological constant down to the observed value. Here, we analyse this possibility in some detail. In four dimensions, and after the moduli are stabilized, branes interact via repulsive long range forces. Because of that, the Coleman-de Luccia (CdL) instanton for coincident brane nucleation may not exist, unless there is some short range interaction which keeps the branes together. If the CdL instanton exists, we find that the degeneracy factor depends only mildly on the ambient de Sitter temperature, and does not switch off even in the case of tunneling from flat space. This would result in catastrophic decay of the present vacuum. If, on the contrary, the CdL instanton does not exist, coindident brane nucleation may still proceed through a "static" instanton, representing pair creation of critical bubbles -- a process somewhat analogous to thermal activation in flat space. In that case, the branes may stick together due to thermal symmetry restoration, and the pair creation rate depends exponentially on the ambient de Sitter temperature, switching off sharply as the temperature approaches zero. Such static instanton may be well suited for the "saltatory" relaxation scenario proposed by Feng et al.Comment: 38 pages, 6 figures. Replaced with typos correcte

    The challenge and response to global tourism in the post-modern era: the commodification, reconfiguration and mutual transformation of Habana Vieja, Cuba

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    There is a growing literature on the symbolic and cultural meanings of tourism and the ways in which cities are increasingly competing for tourists through the promotion of cultural assets and different forms of spectacle in the `tourist bubble'. To date, research on the role and impact of tourism in cities has largely been confined to those in Western, post-industrial economies. This paper examines the growth of cultural tourism in the central area of Havana, Cuba, and explores the range of unique, devolved, state-owned enterprises that are attempting to use tourism as a funding mechanism to achieve improvements in the social and cultural fabric of the city for the benefit of residents. The paper concludes with an assessment of the implications of this example for our understanding of how the pressures for restructuring and commodification can be moderated at the city level. Copyright 2008 SAGE Publications. All rights reserved. Not for commercial use or unauthorized distribution

    Experimental validation of gallium production and isotope-dependent positron range correction in PET

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    Abstract Positron range (PR) is one of the important factors that limit the spatial resolution of positron emission tomography (PET) preclinical images. Its blurring effect can be corrected to a large extent if the appropriate method is used during the image reconstruction. Nevertheless, this correction requires an accurate modelling of the PR for the particular radionuclide and materials in the sample under study. In this work we investigate PET imaging with 68Ga and 66Ga radioisotopes, which have a large PR and are being used in many preclinical and clinical PET studies. We produced a 68Ga and 66Ga phantom on a natural zinc target through (p,n) reactions using the 9-MeV proton beam delivered by the 5-MV CMAM tandetron accelerator. The phantom was imaged in an ARGUS small animal PET/CT scanner and reconstructed with a fully 3D iterative algorithm, with and without PR corrections. The reconstructed images at different time frames show significant improvement in spatial resolution when the appropriate PR is applied for each frame, by taking into account the relative amount of each isotope in the sample. With these results we validate our previously proposed PR correction method for isotopes with large PR. Additionally, we explore the feasibility of PET imaging with 68Ga and 66Ga radioisotopes in proton therapy.We acknowledge support from the Spanish MINECO through projects FPA2010-17142, FPA2013-41267-P, CSD-2007-00042 (CPAN), and the RTC-2015-3772-1 grant. We also acknowledge support from Comunidad de Madrid via the TOPUS S2013/MIT-3024 project

    Wavelets techniques for pointwise anti-Holderian irregularity

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    In this paper, we introduce a notion of weak pointwise Holder regularity, starting from the de nition of the pointwise anti-Holder irregularity. Using this concept, a weak spectrum of singularities can be de ned as for the usual pointwise Holder regularity. We build a class of wavelet series satisfying the multifractal formalism and thus show the optimality of the upper bound. We also show that the weak spectrum of singularities is disconnected from the casual one (denoted here strong spectrum of singularities) by exhibiting a multifractal function made of Davenport series whose weak spectrum di ers from the strong one

    Lepton Dipole Moments and Rare Decays in the CP-violating MSSM with Nonuniversal Soft-Supersymmetry Breaking

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    We investigate the muon anomalous magnetic dipole moment (MDM), the muon electric dipole moment (EDM) and the lepton-flavour-violating decays of the τ\tau-lepton, τμγ\tau \to \mu \gamma and τ3μ\tau\to 3\mu, in the CP-violating Minimal Supersymmetric Standard Model (MSSM) with nonuniversal soft-supersymmetry breaking. We evaluate numerically the muon EDM and the branching ratios B(τμγ)B(\tau \to \mu\gamma) and B(τ3μ)B(\tau \to 3\mu), after taking into account the experimental constraints from the electron EDM and muon MDM. Upon imposition of the experimental limits on our theoretical predictions for the aforementioned branching ratios and the muon MDM, we obtain an upper bound of about 1023ecm10^{-23} e\cdot cm on the muon EDM which lies well within the explorable reach of the proposed experiment at BNL.Comment: Latex, 26 pages, 8 figures, accepted for publication in Phys. Rev.
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