600 research outputs found

    Experimental estimation of the residual fatigue life of in-service wind turbine bolts

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    This study presents an experimental methodology aimed at estimating the residual fatigue life of in-service wind turbine bolts. The main objective is to assess the residual life of the bolts to plan their replacement and to avoid unexpected breakages of wind turbine blade connections. To develop the methodology, M16 bolts of quality 10.9 with controlled predamage were used, simulating in-service operating conditions. The fatigue tests were carried out taking care to place the nut at the point on the bolt that produces the highest damage at the same point where the predamage was performed. In addition, the influence of a possible angular positioning error on the residual fatigue life has been investigated. The residual fatigue life is estimated from the difference in fatigue life of new bolt tests and the fatigue life of predamaged bolt tests, simulating service conditions. Special care has been taken to guarantee that the most damaged zone of the bolt in service is also in the position that produces the highest damage during tests. An experimental procedure for determining the fatigue life of a new bolt from tests conducted on a bolt under the same operating conditions was developed. The developed methodology has been applied to M20 bolts belonging to real turbines in service

    Limited SHIV env diversification in macaques failing oral antiretroviral pre-exposure prophylaxis

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    BACKGROUND: Pre-exposure prophylaxis (PrEP) with daily Truvada [a combination of emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF)] is a novel HIV prevention strategy recently found to prevent HIV transmission among men who have sex with men and heterosexual couples. Acute infection in adherent persons who fail PrEP will inevitably occur under concurrent antiretroviral therapy, thus raising questions regarding the potential impact of PrEP on early viral dynamics. We investigated viral evolution dynamics in a macaque model of PrEP consisting of repeated rectal exposures to SHIV(162P3) in the presence of PrEP. RESULTS: Four macaques were infected during daily or intermittent PrEP with FTC or FTC/TDF, and five were untreated controls. SHIV env sequence evolution was monitored by single genome amplification with phylogenetic and sequence analysis. Mean nucleotide divergence from transmitted founder viruses calculated 17 weeks (range = 12–20) post peak viremia was significantly lower in PrEP failures than in control animals (7.2 × 10(-3) compared to 1.6 × 10(-2) nucleotide substitutions per site per year, respectively, p < 0.0001). Mean virus diversity was also lower in PrEP failures after 17 weeks (0.13% vs. 0.53% in controls, p < 0.0001). CONCLUSIONS: Our results in a macaque model of acute HIV infection suggest that infection during PrEP limits early virus evolution likely because of a direct antiviral effect of PrEP and/or reduced target cell availability. Reduced virus diversification during early infection might enhance immune control by slowing the selection of escape mutants

    ¿Comentario filosófico de textos o comentario de textos filosóficos?

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    Clásicamente el comentario de textos ha sido un elemento en la formación académica filosófica y su dominio, un requisito para el acceso a la docencia. Sorprendentemente, esta técnica de aprendizaje disfruta actualmente de una privilegiada actualidad, ya que resulta metodología clave en los cambios curriculares de la Filosofía en la enseñanza preuniversitaria. No sería necesario recordar cómo anteriores intentos de sustituir el programa oficial ya habían considerado la conveniencia de incluir lecturas de filósofos en la perspectiva del comentario de textos. Estos intentos, sin embargo, no alcanzaron sus objetivos por un conjunto de razones, como por ejemplo las inercias del sistema (entre las cuales no es despreciable la presencia final de una prueba de selectividad), los obstáculos de la propia estructura educativa e, incluso, la falta de actualización en las innovaciones metodológicas propuestas. Aunque no consideramos que esta última sea la razón fundamental de la triste presencia curricular de la Filosofía, como profesores entendemos que nuestra aportación radica actualmente en fundamentar y documentar un debate, la marginación del cual no haría más que agravar la situación comentada. Aunque las posiciones teóricas en la Didáctica de la Filosofía alemana son muy variadas, por lo que respecta a comentario de textos resultan especialmente significativas aquellas que podríamos denominar orientación dialógico-pragmática y paidológica. La orientacion dialógico-pragmática, de la cual veremos más adelante las aportaciones de Ekkehard Martens, Klaus Langebeck, Gisela Raupach-Strey y Ute Siebert, propone lo que a efectos expositivos denominaremos 'comentario filosófico de textos'. Por el contrario, Wulff D. Rehfus, Helmut Conrads, Michael Müller y Johannes Rohbeck abogan, en una orientación paidológica, por el 'comentario de textos filosóficos'

    Study of overall and local electrochemical responses of oxide films grown on CoCr alloy under biological environments

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    The interaction of the physiological medium and living tissues with the implant surfaces in biological environments is regulated by biopotentials that induce changes in the chemical composition, structure and thickness of the oxide film. In this work, oxide films grown on CoCr alloys at 0.5 V vs Ag/AgCl and 0.7 V vs Ag/AgCl have been characterized through overall and localized electrochemical techniques in a phosphate buffer solution and 0.3% hyaluronic acid. Nanopores of 10–50 nm diameter are homogeneously distributed along the surface in the oxide film formed at 0.7 V vs Ag/AgCl. The distribution of the Constant Phase Element studied by local electrochemical impedance spectroscopy showed a three-dimensional (3D) model on the oxide films grown at 0.5 V vs Ag/AgCl and 0.7 V vs Ag/AgCl. This behaviour is especially noticeable in oxide films grown at 0.7 V vs Ag/AgCl, probably due to surface inhomogeneities, and resistive properties generated by the potentiostatic growth of the oxide film.This work was supported by the Spanish National government [MINECO-MAT2011-29152-C02-01].Peer reviewe

    Measuring Enzymatic HIV-1 Susceptibility to Two Reverse Transcriptase Inhibitors as a Rapid and Simple Approach to HIV-1 Drug-Resistance Testing

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    Simple and cost-effective approaches for HIV drug-resistance testing are highly desirable for managing increasingly expanding HIV-1 infected populations who initiate antiretroviral therapy (ART), particularly in resource-limited settings. Non-nucleoside reverse trancriptase inhibitor (NNRTI)-based regimens with an NRTI backbone containing lamivudine (3TC) or emtricitabine (FTC) are preferred first ART regimens. Failure with these drug combinations typically involves the selection of NNRTI- and/or 3TC/FTC- resistant viruses. Therefore, the availability of simple assays to measure both types of drug resistance is critical. We have developed a high throughput screening test for assessing enzymatic resistance of the HIV-1 RT in plasma to 3TC/FTC and NNRTIs. The test uses the sensitive “Amp-RT” assay with a newly-developed real-time PCR format to screen biochemically for drug resistance in single reactions containing either 3TC-triphosphate (3TC-TP) or nevirapine (NVP). Assay cut-offs were defined based on testing a large panel of subtype B and non-subtype B clinical samples with known genotypic profiles. Enzymatic 3TC resistance correlated well with the presence of M184I/V, and reduced NVP susceptibility was strongly associated with the presence of K103N, Y181C/I, Y188L, and G190A/Q. The sensitivity and specificity for detecting resistance were 97.0% and 96.0% in samples with M184V, and 97.4% and 96.2% for samples with NNRTI mutations, respectively. We further demonstrate the utility of an HIV capture method in plasma by using magnetic beads coated with CD44 antibody that eliminates the need for ultracentifugation. Thus our results support the use of this simple approach for distinguishing WT from NNRTI- or 3TC/FTC-resistant viruses in clinical samples. This enzymatic testing is subtype-independent and can assist in the clinical management of diverse populations particularly in resource-limited settings

    Fungal grapevine trunk pathogens associated with Syrah decline in Spain

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    Syrah decline has been increasingly seen and reported in many vineyards worldwide. In recent years, an increase in samples of Vitis vinifera cv. Syrah showing general decline has also been noted in Spain. Sixty-two samples of Syrah grafted grapevines with such symptoms were collected from grapevine nurseries and young vineyards between 2007 and 2009 and subjected to fungal isolation. Species were identified with morphological and molecular methods. Species recovered included Phaeoacremonium, Botryosphaeriaceae and Cylindrocarpon, as well as Pa. chlamydospora and Ca. luteo-olivacea. The study demonstrates that fungal pathogens should be considered potential factors associated with Syrah decline

    Effect of hot-water treatment on grapevine viability, yield components and composition of must

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    Abstract Background and Aims: Hot-water treatment (HWT) has been shown to be effective for the control of several endogenous and exogenous grapevine pests and diseases in dormant grapevine cuttings and young rooted vines. Little is still known, however, about the long-term effect of HWT on plant viability under field conditions. The effect of HWT on the performance of dormant plants in a four-growing seasons study was investigated. Methods and Results: The effect of HWT at 53°C for 30 min on shoot mass, yield parameters and composition of must in dormant grafted plants (Tempranillo cultivar grafted onto 110 Richter rootstock) was evaluated. Eight bundles of 20 grafted plants were assigned to HWT, and eight additional bundles of 20 untreated grafted plants were prepared as a control (non-HWT). Dormant grafted plants were immediately planted in two field sites in April 2007. Shoot fresh mass was evaluated during winter in four consecutive growing seasons. Yield parameters and must composition were evaluated in the third and fourth growing seasons. In general, there was no significant difference in shoot mass at pruning, yield parameters and must components between treatments, with the exception of the must total soluble solids and volumetric mass in the fourth growing season. Conclusions: The findings obtained in this study indicate that HWT at 53°C for 30 min did not affect plant viability, yield parameters and the main components of must composition, and could be successfully used commercially. Significance of the Study: This study represents the first approach to investigate the long-term effect of HWT on plant development, yield and composition of must under field conditions. It suggests that the success of HWT depends not only on the most adequate protocol applied by nurseries, but also on management practices before, during and after the propagation process that could affect the viability of HWT grapevine propagating material

    Application of a self-learning methodology for the enhancement of the oral communication student outcome in International Business studies

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    Effective oral communication is one of the most demanded student outcomes in the labour market, especially for degree students on International Business. Although this outcome is usually evaluated in several subjects along the curriculum, it is barely worked neither inside nor outside the classroom, mainly due to lack of time and to unavailability of proper learning methodologies. The PIMECOE project, an innovation and educational improvement project on this matter, has developed a self-learning methodology on the Effective Oral Communication student outcome, in which auto-diagnosis tests, selflearning tools and peer assessments are conveniently combined to enhance the proficiency level of the students in an autonomous way. As part of this project, and after some previous successful pilot studies, we have run this methodology with International Bussiness' students within the "Learning instruments and techniques" subject during the first semester of the 2018/2019 academic year at the Universitat de València. After carrying out a quantitative analysis of the results, we have found generalised improvements on the proficiency level of the oral communication outcome of the participant students. Satisfaction surveys suggest that the application of this methodology has really helped the student to become conscious of unrealised weaknesses and therefore to boost their oral skills

    Estudio fenológico y caracterización morfológica de variedades tradicionales de manzano y melocotonero

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    Las variedades locales de frutales seleccionadas a lo largo de los años por los agricultores, son muy interesantes para preservar la biodiversidad y los recursos fitogenéticos, ya que presentan unas características organolépticas peculiares y un valor cultural irremplazable. En 2007 se inició un trabajo de recuperación de variedades tradicionales de frutales en Andalucía (Proyecto INIA, RF2007-00027- C06-05) que contempla su prospección, localización, recogida de material vegetal, caracterización morfológica y molecular, multiplicación, documentación y mantenimiento en colección. En este trabajo se han caracterizado morfológicamente mediante caracteres UPOV las flores, hojas y ramos de un año, de cinco variedades tradicionales de manzano (Malus x domestica Borkh.) y dos de melocotonero [Prunus persica (L) Batsch], no estudiadas con anterioridad. Se ha evaluado la floración en la campaña 2011 y se han realizado los fenogramas correspondientesMICINN, INIA y Fondos FEDE

    Rutas metabólicas importantes en la formación de velo de flor

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    La crianza biológica de los vinos tipo Sherry es un proceso que se caracteriza por la formación y mantenimiento sobre la superficie del vino de una película (biofilm) de levaduras llamada “velo de flor” que aporta el aroma y sabor característico de estos vinos. Para dilucidar las rutas metabólicas de relevancia en una condición típica de velo de flor, se han identificado enzimas sobreexpresadas de una levadura de flor mediante la técnica de fraccionamiento OFFGEL y detección LTQ Orbitrap XL MS. Como referencia se ha comparado con una condición sin formación de velo de flor. Los resultados indican una sobreexpresión de proteínas en formación de velo relacionadas con las rutas metabólicas del complejo 2‐ cetoglutarato deshidrogenasa, la cadena de transporte de electrones, el ciclo de los ácidos tricarboxílicos (TCA) y de glioxilato, la degradación de isoleucina y leucina, y la biosíntesis de folato, entre otras. Los resultados obtenidos podrían servir como una herramienta para desarrollar estrategias con objeto de mejorar la calidad de los vinos sometidos a procesos tales como la crianza biológica
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