1,111 research outputs found

    Rebrote después de incendio e inversión reproductiva en Erica cinerea y E. vagans

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    Se estudió el crecimiento anual y la distribución de recursos de clones control y de rebrotes en áreas incendiadas y en zonas control en Erica vagans y E. cinerea, encontrándose que no existen diferencias significativas entre ambas especies. Sin embargo, el crecimiento de los rebrotes tras el incendio fue superior al estimado en los controles. La asignación reproductiva en el rebrote después de incendios disminuyó en ambas especies, sobre todo en E. cinerea. Los patrones de asignación reproductiva dependientes del tamaño que aparecen en los controles no se encuentran en el rebrote, lo cual sugiere una asignación reproductiva plástica.Post-fire growth and annual growth of control branches were studied in Erica vagans and E. cinerea in two northem Spain localities. The dry weight of the resprouts was greater than that of the control branches. However, neither growth of the control branches nor resprouts differed among species. Reproductive allocation did not show differences among species, but significantly decreased in burned areas, specially in E. cinerea. Reproductive allocation was size-dependent in control branches, but this pattem did not appear in the resprouts. This variations suggest a flexible reproductive strategy

    Regulation of Ace2-dependent genes requires components of the PBF complex in schizosaccharomyces pombe

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    The division cycle of unicellular yeasts is completed with the activation of a cell separation program that results in the dissolution of the septum assembled during cytokinesis between the 2 daughter cells, allowing them to become independent entities. Expression of the eng1+ and agn1+ genes, encoding the hydrolytic enzymes responsible for septum degradation, is activated at the end of each cell cycle by the transcription factor Ace2. Periodic ace2+ expression is regulated by the transcriptional complex PBF (PCB Binding Factor), composed of the forkhead-like proteins Sep1 and Fkh2 and the MADS box-like protein Mbx1. In this report, we show that Ace2-dependent genes contain several combinations of motifs for Ace2 and PBF binding in their promoters. Thus, Ace2, Fkh2 and Sep1 were found to bind in vivo to the eng1+ promoter. Ace2 binding was coincident with maximum level of eng1+ expression, whereas Fkh2 binding was maximal when mRNA levels were low, supporting the notion that they play opposing roles. In addition, we found that the expression of eng1+ and agn1+ was differentially affected by mutations in PBF components. Interestingly, agn1+ was a major target of Mbx1, since its ectopic expression resulted in the suppression of Mbx1 deletion phenotypes. Our results reveal a complex regulation system through which the transcription factors Ace2, Fkh2, Sep1 and Mbx1 in combination control the expression of the genes involved in separation at the end of the cell division cycle

    Incrementalmaintenance of discovered fuzzy association rules

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    Fuzzy association rules (FARs) are a recognized model to study existing relations among data, commonly stored in data repositories. In real-world applications, transactions are continuously processed with upcoming new data, rendering the discovered rules information inexact or obsolete in a short time. Incremental mining methods arise to avoid re-runs of those algorithms from scratch by re-using information that is systematically maintained. These methods are useful for extracting knowledge in dynamic environments.However, executing the algorithms only to maintain previously discovered information creates inefficiencies in real-time decision support systems. In this paper, two active algorithms are proposed for incremental maintenance of previously discovered FARs, inspired by efficient methods for change computation. The application of a generic form of measures in these algorithms allows the maintenance of a wide number of metrics simultaneously. We also propose to compute data operations in real-time, in order to create a reduced relevant instance set. The algorithms presented do not discover new knowledge; they are just created to efficiently maintain valuable information previously extracted, ready for decision making. Experimental results on education data and repository data sets showthat our methods achieve a good performance. In fact, they can significantly improve traditional mining, incremental mining, and a naïve approach.Iberoamerican Association of Postgraduate Universities (AUIP

    Thermal Analysis of Healthy and Ecological Friendly Flame Retardants for Textiles

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    Flame Retardants (FR) are a group of anthropogenic environmental contaminants used at a relatively high concentration in many applications. Currently, the largest marked group of FRs is halogenated FR, and many of them are considered toxic, persistent and bio accumulative. Non-halogenated alternatives are a possible solution for the problem, but there is a lack of knowledge concerning environmental impact, health risks during the production process and final use. The main objective of the LIFE-FLAREX project that supports this work, is the mitigation of the environmental and human health impact of flame retardants used in textiles, looking for new efficient more ecological and healthy alternatives, able to replace the most common FR’s that include toxic compounds like halogens, formaldehyde and antimony.  The aim of this work   is to determine the effect of conventional and ecological flame retardants on cotton and polyester fabrics by the application of differential scanning calorimetry DSC and thermogravimetric analysis TGA. Results have been compared with those given by the best FR applied to cotton/polyester blended fabric. The application of DSC up to 550°Cand TGA up to 600°C in N2 and O2 atmospheres give results that are in accordance with those yielded by the micro-scale combustion calorimeter. Onset temperatures  of decomposition, steps of loss of mass by temperature and final residues, enable to evaluate the thermal efficiency of the different flame retardants. Results have been compared with those given by the application of ammonium polyphosphate and guanidine phosphate on cotton/polyester 50/50 blend. Keywords: Thermal Analysis, Flame retardant, Cotton, Polyeste

    Government of Margarita island in the sixteenth century: legacy and female presence

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    Artículo de la sección: Varia.El artículo trata de analizar y resaltar las especiales características que tuvo el gobierno de la isla Margarita en el siglo XVI, puesto que allí se dio una particular situación histórica que le confiere una marcada originalidad. Durante ese tiempo, la isla estuvo gobernada por varios miembros de una misma familia —los Villalobos—, que fueron heredando el cargo y dirigieron los destinos del territorio procurando velar por sus propios intereses al tiempo que promovían el desarrollo interno y encauzaban las relaciones con las áreas vecinas. Aunque seguramente, el aspecto más llamativo del gobierno margariteño en ese tiempo resida en la presencia de mujeres al frente del mismo.The article aims to discuss and highlight the special features of the Margarita Island government during the sixteenth century, since there, took place a particular historical situation that gives it a marked originality. During that time, the island was ruled by several members of the same family, the Villalobos family, who were inheriting the position and guided the fates of the territory, seeking their own interests while promoting domestic development and managing relations with the neighboring areas. Although surely the most outstanding aspect of the government at that time resides in the presence of women in charge.Departamento de Historia Moderna y de América, Universidad de Granad

    Stress compensation by gap monolayers for stacked InAs/GaAs quantum dots solar cells

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    In this work we report the stacking of 10 and 50 InAs quantum dots layers using 2 monolayers of GaP for stress compensation and a stack period of 18 nm on GaAs (001) substrates. Very good structural and optical quality is found in both samples. Vertical alignment of the dots is observed by transmission electron microscopy suggesting the existence of residual stress around them. Photocurrent measurements show light absorption up to 1.2 μm in the nanostructures together with a reduction in the blue response of the device. As a result of the phosphorus incorporation in the barriers, a very high thermal activation energy (431 meV) has also been obtained for the quantum dot emission

    Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol

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    P. 253-257Dietary fibers are widely used in hypoglycaemic, hypolipidemic, slimming diets. It is probable that their ingestion coincides with the oral administration of drugs and a modification of their pharmacokinetics can appear. In the present study, the influence of two soluble fibers (guar gum and psyllium) was evaluated on the pharmacokinetics of ethinyloestradiol (EE) when they were administered together to female rabbits via the oral route. Three groups of rabbits were used. All animals received 1 mg/kg of EE; this compound was administered alone in the control group and with 3.5 g of guar gum or psyllium in the other two groups. When guar gum was administered, there was a decrease in the extent of EE absorbed, but no change was observed in the rate of absorption. When psyllium was administered, the extent of EE absorbed increased slightly and the rate of absorption was slower.S

    Reduced order models based on local POD plus Galerkin projection

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    A method is presented to accelerate numerical simulations on parabolic problems using a numerical code and a Galerkin system (obtained via POD plus Galerkin projection) on a sequence of interspersed intervals. The lengths of these intervals are chosen according to several basic ideas that include an a priori estimate of the error of the Galerkin approximation. Several improvements are introduced that reduce computational complexity and deal with: (a) updating the POD manifold (instead of calculating it) at the end of each Galerkin interval; (b) using only a limited number of mesh points to calculate the right hand side of the Galerkin system; and (c) introducing a second error estimate based on a second Galerkin system to account for situations in which qualitative changes in the dynamics occur during the application of the Galerkin system. The resulting method, called local POD plus Galerkin projection method, turns out to be both robust and efficient. For illustration, we consider a time-dependent Fisher-like equation and a complex Ginzburg–Landau equation
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