962 research outputs found
Ausencia de efectos en los balances de nutrientes después de defoliación por insectos en una cuenca
Nutrient export via streamflow after the defoliation by Gonipterus scutellatus Gill. in a Eucalyptus globulus Labill. watershed in Galicia (NW Spain) was monitored from 1999 to 2006. The effects of such defoliation on nutrients balance had not been previously evaluated. Insect defoliation caused no significant changes in streamflow nutrient concentrations during the period of study compared with the pre-perturbation period and nutrient exports in streamflow were compensated via precipitation in all cases. The results presented here show that in spite of the reduction in E.globulus growth caused by the defoliation, nutrient balances were positive, suggesting a minor impact in the soil-plant system nutrient budget.Se ha desarrollado un estudio entre 1999 y 2006 para evaluar el efecto de la defoliación por Gonypterus scutellatus Gill. sobre la pérdida de nutrientes por escorrentÃa en una cuenca experimental de Eucalyptus globulus Labill. Galicia (NW España). Esos efectos no habÃan sido evaluados hasta ahora.
La defoliación no causó variaciones significativas en las concentraciones de nutrientes durante el perÃodo de estudio en relación con el perÃodo pre-perturbación y las entradas de nutrientes por precipitación compensaron las salidas de nutrientes por escorrentÃa en todos los casos.
Los resultados que se presentan en este trabajo muestran que a pesar de la reducción en el crecimiento de E.globulus causado por la defoliación, los balances de nutrientes fueron positivos, sugiriendo un impacto menor en el balance de nutrientes del sistema suelo-planta
Efectos de la secuencia incendio-corta a hecho-selección de brotes en la pérdida de nutrientes por escorrentÃa en una cuenca experimental de E. globulus en Galicia (NW de España)
An experimental study was carried out between 1987 and 1999, to assess the effect of the sequence wildfire-clearfelling-coppice sprout selection thinning, on streamflow nutrient export in a Eucalyptus globulus Labill. watershed in Galicia (NW Spain). The effects of such a sequence on nutrient export via streamflow had not been previously evaluated. A wildfire in 1989 caused a significant increase in nutrient exports in streamflow during the following two years. No significant effect was observed the third year after wildfire. After clearfelling in 1992, inputs via precipitation compensated for nutrient exports in streamflow, except for K the first year following harvest and NO3- during the three years after this operation. Coppice sprout selection thinning in 1995 had less effect on nutrient exports than wildfire or harvest. The results presented here could may help in evaluating the effects of current intensive forest management and perturbations that affect eucalypt stands in NW Spain.Se ha desarrollado un estudio entre 1987 y 1999 para evaluar el efecto de la secuencia incendio-corta a hecho-selección de brotes sobre la pérdida de nutrientes por escorrentÃa en una cuenca experimental de Eucalyptus globulus Labill. en Galicia (NW España). Esos efectos no habÃan sido evaluados hasta ahora.
Un incendio en 1989 causó un aumento significativo de las pérdidas de nutrientes por escorrentÃa durante los dos años siguientes. Ningún efecto era apreciable al tercer año del incendio. Después de la corta a hecho del arbolado quemado en 1992, las entradas por precipitación compensaron las pérdidas por escorrentÃa, a excepción del K el primer año después de esta operación y del NO3- durante los tres años siguientes. La selección de brotes ejecutada en 1995 tuvo un efecto mucho menor en las pérdidas de nutrientes por escorrentÃa que el incendio o la corta.
Los resultados que se presentan en este trabajo pueden ayudar a los gestores a evaluar los efectos del manejo intensivo y de las perturbaciones que afectan a las masas de eucalipto en el NW de España
Application of HOSVD to Aerodynamics. The Problem of Shock Waves
Efficient interpolation in aerodynamic databases is important for the aeronautic industry because of its implication on both the cost and time needed to complete design cycles. In this study a method based on high-order singular value decomposition is presented focusing on the problems associated with the shock wave like structures that do not suit well with this kind of methods. To illustrate the methodology, the flow around a two-dimensional airfoil is considered at a Reynolds number of 20 × 106 with three free parameters, namely, the Mach number, the angle of attack, and the flap deflection angle in the ranges of [0.4, 0.8], [¿3º, 3º], and [¿5º, 5º], respectively. The method is robust in the sense of being able to deal with very different flow topologies
Neural correlates of phonological, orthographic and semantic reading processing in dyslexia
Developmental dyslexia is one of the most prevalent learning disabilities, thought to be associated with dysfunction in the neural systems underlying typical reading acquisition. Neuroimaging research has shown that readers with dyslexia exhibit regional hypoactivation in left hemisphere reading nodes, relative to control counterparts. This evidence, however, comes from studies that have focused only on isolated aspects of reading. The present study aims to characterize left hemisphere regional hypoactivation in readers with dyslexia for the main processes involved in successful reading: phonological, orthographic and semantic. Forty-one participants performed a demanding reading task during MRI scanning. Results showed that readers with dyslexia exhibited hypoactivation associated with phonological processing in parietal regions; with orthographic processing in parietal regions, Broca's area, ventral occipitotemporal cortex and thalamus; and with semantic processing in angular gyrus and hippocampus. Stronger functional connectivity was observed for readers with dyslexia than for control readers 1) between the thalamus and the inferior parietal cortex/ventral occipitotemporal cortex during pseudoword reading; and, 2) between the hippocampus and the pars opercularis during word reading. These findings constitute the strongest evidence to date for the interplay between regional hypoactivation and functional connectivity in the main processes supporting reading in dyslexia. Keywords: Dyslexia, Reading, Hypoactivation, Functional connectivity, Thalamus, Hippocampu
Intrauterine infusion of platelet-rich plasma for severe Asherman syndrome: a cutting-edge approach
Asherman syndrome (AS) consists of intrauterine adhesions development as a consequence of trauma, radiation, or infection in the endometrium. Clinical symptoms include menstrual alterations, infertility, and pregnancy complications, such as recurrent pregnancy loss or abnormal placentation. In this article, we performed a narrative review of the literature, searching electronic databases (i.e., Medline, Pubmed, and Google Scholar) to summarize the available pieces of evidence about epidemiology, pathophysiology, diagnosis, and treatment of AS. Hysteroscopy is essential for diagnosis and treatment, although adhesions may recur. Different postoperative therapies have been proposed to prevent recurrence and restore impaired endometrial function and promote endometrial regeneration, although these effects are usually temporary. We report a case of AS with adhesion recurrence and endometrial atrophy who was successfully treated with intrauterine autologous platelet–rich plasma (PRP) infusion. This therapy allowed endometrial tissue regeneration, leading to increased vascularity and endometrium thickness, and restoration of endometrial function that led to a successful pregnancy. Though there is limited experience supporting the use of PRP to improve endometrial function, it has been safely used in other fields of medicine; besides, it is easy to obtain, not expensive, and harmless being an autologous source. Future studies are encouraged to further assess this approach to treat AS
Estudio comparativo de la influencia de las fibras en la retracción de los morteros reciclados
Construction and demolition waste can be used as a substitution of natural aggregate in mortar and concrete elaboration. A poorer quality of recycled aggregates generally has negative impact on mortar properties. Shrinkage is one of the properties that experiences worse outcome due to the higher absorption of recycled aggregates. This research evaluates the potential shrinkage of mortars elaborated with recycled concrete aggregates both with and without fibres addition, as well as the relation between moisture loss and shrinkage caused by mortar drying process using a capacitive sensor of the authors’ own design. Two different mortar dosages 1:3 and 1:4 and three fiber types: polypropylene fiber, fiberglass and steel fiber, in different proportions were used. Obtained results show that the use of polypropylene fiber improves the recycled mortars performance against shrinkage in 0.2%. Moreover, a clear relation between dry shrinkage and moisture loss was observed.Los Residuos de Construcción y Demolición pueden ser usados como sustitución de los áridos naturales en la fabricación de morteros y hormigones. La peor calidad de los áridos reciclados empeora de manera general las propiedades de los morteros, siendo la retracción una de las que más se ve afectada. Esta investigación, estudia la retracción de los morteros elaborados con arena reciclada de hormigón con y sin adicción de fibras, asà como la relación existente entre la perdida de humedad y la retracción por secado mediante un sensor capacitivo de diseño propio. Se han empleado dos dosificaciones diferentes 1:3 y 1:4 y tres tipos de fibras: polipropileno, vidrio y acero, en distintas proporciones. Los resultados muestran que la adición de fibras de polipropileno en un 0,2% mejora significativamente la retracción en los morteros reciclados. Además, se ha obtenido una relación clara entre la retracción por secado y la perdida de humedad
Multiple-time correlation functions for non-Markovian interaction: Beyond the Quantum Regression Theorem
Multiple time correlation functions are found in the dynamical description of
different phenomena. They encode and describe the fluctuations of the dynamical
variables of a system. In this paper we formulate a theory of non-Markovian
multiple-time correlation functions (MTCF) for a wide class of systems. We
derive the dynamical equation of the {\it reduced propagator}, an object that
evolve state vectors of the system conditioned to the dynamics of its
environment, which is not necessarily at the vacuum state at the initial time.
Such reduced propagator is the essential piece to obtain multiple-time
correlation functions. An average over the different environmental histories of
the reduced propagator permits us to obtain the evolution equations of the
multiple-time correlation functions. We also study the evolution of MTCF within
the weak coupling limit and it is shown that the multiple-time correlation
function of some observables satisfy the Quantum Regression Theorem (QRT),
whereas other correlations do not. We set the conditions under which the
correlations satisfy the QRT. We illustrate the theory in two different cases;
first, solving an exact model for which the MTCF are explicitly given, and
second, presenting the results of a numerical integration for a system coupled
with a dissipative environment through a non-diagonal interaction.Comment: Submitted (04 Jul 04
A computationally efficient reduced order model to generate multi-parameter fluid-thermal databases
A reduced order model (ROM) is proposed to generate multi-parameter databases of some fluid-thermal problems, using a combination of proper orthogonal decomposition, a gradient-like method, and a continuation method. The resulting ROM greatly reduces the CPU time required by slower methods based on genetic algorithm formulations. As a byproduct, the number of required snapshots is also reduced, which yields an additional improvement of the computational efficiency. The work presented in this article aims to facilitate the use of ROMs in industrial environments, in which time is a very important asset. The methodology is illustrated with the non-isothermal flow past a backward-facing step in the laminar regime, which is a representative problem, related to the engineering design of micro-heat sinks
PHF2 regulates homology-directed DNA repair by controlling the resection of DNA double strand breaks
Post-translational histone modifications and chromatin remodelling play a critical role controlling the integrity of the genome. Here, we identify histone lysine demethylase PHF2 as a novel regulator of the DNA damage response by regulating DNA damage-induced focus formation of 53BP1 and BRCA1, critical factors in the pathway choice for DNA double strand break repair. PHF2 knockdown leads to impaired BRCA1 focus formation and delays the resolution of 53BP1 foci. Moreover, irradiation-induced RPA phosphorylation and focus formation, as well as localization of CtIP, required for DNA end resection, to sites of DNA lesions are affected by depletion of PHF2. These results are indicative of a defective resection of double strand breaks and thereby an impaired homologous recombination upon PHF2 depletion. In accordance with these data, Rad51 focus formation and homology-directed double strand break repair is inhibited in cells depleted for PHF2. Importantly, we demonstrate that PHF2 knockdown decreases CtIP and BRCA1 protein and mRNA levels, an effect that is dependent on the demethylase activity of PHF2. Furthermore, PHF2-depleted cells display genome instability and are mildly sensitive to the inhibition of PARP. Together these results demonstrate that PHF2 promotes DNA repair by homologous recombination by controlling CtIP-dependent resection of double strand breaks.España Ministerio de Ciencia e Innovacion SAF2016-80626-REspaña, Fundación Canaria Instituto de Investigación Sanitaria de Canarias (FIISC) [PIFUN16/18
- …