385 research outputs found

    Biografía inédita de Francisco de Quintana: recuperación de un novelista olvidado

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    This article seeks to reveal unpublished data from Francisco de Quintana, a sixteeth century author scarcely studied by literary critics to this day. The research in both primary sources and in his literary work has led to the discovery of substantial information about this intimate friend of Lope de Vega. In addition to providing new biographical evidence, this communication interrelates key events of his life with his writing.Este artículo pretende desvelar datos inéditos de Francisco de Quintana, escritor del seiscientos escasamente estudiado por la crítica literaria hasta nuestros días. La investigación, a partir tanto de fuentes primarias como de su obra literaria, ha supuesto el hallazgo de información sustancial sobre este íntimo amigo de Lope de Vega. Además de aportar nuevos testimonios biográficos, esta comunicación interrelaciona acontecimientos fundamentales de su vida con su obra literaria

    Quasinormal Modes and Stability Criterion of Dilatonic Black Hole in 1+1 and 4+1 Dimensions

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    We study the stability of black holes that are solutions of the dilaton gravity derived from string-theoretical models in two and five dimensions against to scalar field perturbations, using the Quasinormal Modes (QNMs) approach. In order to find the QNMs corresponding to a black hole geometry, we consider perturbations described by a massive scalar field non-minimally coupled to gravity. We find that the QNM's frequencies turn out to be pure imaginary leading to purely damped modes, that is in agreement with the literature of dilatonic black holes. Our result exhibits the unstable behavior of the considered geometry against the scalar perturbations. We consider both the minimal coupling case, i.e., for which the coupling parameter ζ\zeta vanishes, and the case ζ=1/4\zeta={1/4}.Comment: sevarl changes, some reference was added, 10 pages, 4 figure

    Predictive modelling using pathway scores: robustness and significance of pathway collections

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    Background Transcriptomic data is often used to build statistical models which are predictive of a given phenotype, such as disease status. Genes work together in pathways and it is widely thought that pathway representations will be more robust to noise in the gene expression levels. We aimed to test this hypothesis by constructing models based on either genes alone, or based on sample specific scores for each pathway, thus transforming the data to a ‘pathway space’. We progressively degraded the raw data by addition of noise and examined the ability of the models to maintain predictivity. Results Models in the pathway space indeed had higher predictive robustness than models in the gene space. This result was independent of the workflow, parameters, classifier and data set used. Surprisingly, randomised pathway mappings produced models of similar accuracy and robustness to true mappings, suggesting that the success of pathway space models is not conferred by the specific definitions of the pathway. Instead, predictive models built on the true pathway mappings led to prediction rules with fewer influential pathways than those built on randomised pathways. The extent of this effect was used to differentiate pathway collections coming from a variety of widely used pathway databases. Conclusions Prediction models based on pathway scores are more robust to degradation of gene expression information than the equivalent models based on ungrouped genes. While models based on true pathway scores are not more robust or accurate than those based on randomised pathways, true pathways produced simpler prediction rules, emphasizing a smaller number of pathways

    Antagonistic effect of Trichoderma harzianum VSL291 on phytopathogenic fungi isolated from cocoa (Theobroma cacao L.) fruits

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    In this study we evaluated the antagonism in vitro of Trichoderma harzianum strain VSL291 against 18 pathogens of cocoa fruits in dual culture. T. harzianum VSL291 inhibited the growth of the phytopathogenic fungi tested between 10.54 and 85.43%. The mycoparasitism of Moniliophthora roreri by T. harzianum VSL291 was studied by light and scanning electron microscopy. T. harzianum VSL291 hyphae grew in parallel with the hyphae of M. roreri and in some places these were united with the hyphae of the cocoa pathogen through small structures like apresorious that tangled in the pathogenic fungus preventing its growth. T. harzianum VSL291 produced lytic enzymes: β-1,3-glucanases, chitinases, proteases, xylanases and lipases, when grown in minimal medium, with fungal cell walls as the sole carbon source. The highest proteolytic activities detected in T. harzianum VSL291 broth with M. roreri, Penicillium expansum and Byssochlamys spectabilis cell walls appear to be associated with increased activities of β-1,3 glucanases, chitinases, lipases, proteases and xylanases and biocontrol index derived from the experiments of confrontation. These results suggest that proteolytic enzymes according to their degree of induction could participate in the antagonistic effect of T. harzianum VSL291 against the fungi tested.Key words: Antagonism, Trichoderma harzianum, mycoparasitism, phytopathogenic fung

    Pediatric metabolic syndrome definitions impact prevalence and socioeconomic gradients

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    The choice of pediatric metabolic syndrome (MetS) definition influences prevalence estimates, but further implications, especially on the association with socioeconomic status (SES), are not well-known. This hampers a synthesis of the evidence to help guide the relevant stakeholders. For this reason, we aim to assess the impact of alternative definitions on the prevalence of MetS, the children that are identified, and the association between SES and MetS.Data were used from the Lifelines Cohort Study, a prospective multigenerational cohort in the Netherlands. At baseline 9,754 children participated, of which 5,085 (52.1\ were included in the longitudinal analyses. We computed the prevalence of MetS according to five published definitions and measured the observed positive agreement between pairs of definitions, indicating the proportion of agreement across the average number of MetS cases. Logistic regression was used to assess the association between SES and MetS. All models were adjusted for age and sex; the longitudinal models were also adjusted for baseline MetS status.The prevalence rates of MetS varied between definitions (0.7-3.0\, but positive agreement between MetS definitions was generally fair to good ranging from 0.34 (95\CI) 0.28; 0.41) to 0.66 (95\.58; 0.75) at baseline. At both assessments, we found an inverse association between baseline SES and MetS, which ranged from 0.81 (95\.70; 0.93) to 0.92 (95\.86; 0.98) per definition in the longitudinal analyses with a mean follow-up (SD) of 3.0 (0.75) years.Alternative definitions of MetS lead to differing prevalence estimates, and they agreed on 50\ regardless of which definition was used we concluded low SES was a risk factor for developing MetS.Evidence regarding different definitions of metabolic syndrome in children can be combined because the agreement among definitions is generally fair to good.As low socioeconomic status is a consistent risk factor for developing metabolic syndrome, preventive interventions should preferentially target children from low socioeconomic backgrounds

    Piranoantocianos vinilfenólicos en vinos tintos utilizando levaduras HCDC+.

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    Los piranoantocianos vinilfenólicos son aductos de elevada estabilidad, con interesantes propiedades para la mejora del color en vinos tintos, y que se forman por condensación entre ácidos hidroxicinámicos o sus respectivos vinilfenoles y antocianos procedentes de la uva. Inicialmente se pensaba que la única ruta de formación era exclusivamente química (Schwarz, 2003) en un lento proceso a partir de ácidos hidroxicinámicos, que inducía a cantidades muy pequeñas durante el periodo de envejecimiento de los vinos tintos y podían por tanto ser usadas como age-markers. Recientemente se ha demostrado (Morata et al, 2006 y 2007) que algunas cepas de Saccharomyces spp seleccionadas con alta actividad hidroxicinamato descarboxilasa (HCDC) pueden acelerar la formación de aductos vinilfenólicos durante la fermentación. Estas levaduras descarboxilan los ácidos fenólicos formando vinilfenoles de elevada reactividad que espontáneamente condensan con antocianos de la uva formando una gran variedad de aductos vinilfenólicos dependiendo del tipo de antociano y del ácido hidroxicinámico precursor. Cuantitativamente los derivados más importantes son los del malvidin-3-O-glucosido. Adicionando ácidos hidroxicinámicos a las muestras se verifica que el aducto que se forma en mayor cantidad es el malvidin-3-O-glucosido-4-vinilguaiacol, siendo además el que produce mayor incremento de la intensidad colorante reduciendo a su vez las tonalidades amarillas en vinos. La utilización de cepas de Saccharomyces HCDC+ con o sin adiciones de ácidos hidroxicinámicos, puede constituirse en una interesante herramienta para mejorar el color de vinos tintos

    Validity of the Generalized Second Law of Thermodynamics of the Universe Bounded by the Event Horizon in Brane Scenario

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    In this paper, we examine the validity of the generalized second law of thermodynamics (GSLT) of the universe bounded by the event horizon in brane-world gravity. Here we consider homogeneous and isotropic model of the universe filled with perfect fluid in one case and in another case holographic dark energy model of the universe has been considered. The conclusions are presented point wise.Comment: 8 pages, the paper has been accepted in EPJC for publication. Conclusion has been modified an some references have been adde

    Empleo de fermentaciones secuenciales con levaduras no-Saccharomyces y aplicación de bloqueadores metabólicos para reducir el grado alcohólico en vinos

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    La combinación secuencial de especies no-Saccharomyces y Saccharomyces durante la fermentación y la adición de bloqueadores metabólicos como el furfural, o-vainillina, glicolaldehído y p-benzoquinona pueden resultar unas técnicas de vinificación interesantes para reducir el grado alcohólico del vino. El grado alcohólico se determinó por HPLC-IR y los azúcares residuales mediante tests enzimáticos. Las cepas de levadura 7013 (Torulaspora delbrueckii) y 938 (Schizosaccharomyces pombe) destacaron por su capacidad para reducir significativamente el grado alcohólico (reducción media del 2.1 % v/v) dando lugar a un vino seco (azúcares menor que 1.5 gl-1) en fermentación secuencial con la 7VA (Saccharomyces cerevisiae). La o-vainillina permitió una disminución en el contenido de etanol del 0.54 % v/v a dosis de 50 mg l-1, mientras que el efecto bloqueador del glicolaldehído fue más efectivo a la dosis de 200 mg l-1 con una reducción del 0.95 % v/v. Finalmente con la p-benzoquinona se logró una reducción en el grado alcohólico de hasta 0.85 % v/v

    Crossing the phantom divide with Ricci-like holographic dark energy

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    We study a holographic model for the dark energy considered recently in the literature which postulates an energy density ρR\rho \sim R, where RR is the Ricci scalar curvature. We obtain a cosmological scenario that comes from considering two non-interacting fluids along a reasonable Ansatz for the cosmic coincidence parameter. We adjust the involved parameters in the model according to the observational data and we show that the equation of state for the dark energy experience a cross through the -1 barrier. In addition, we find a disagreement in these parameters with respect to an approach from a scalar field theory.Comment: Match with accepted version by EPJ
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