Time-averaged shallow water model: asymptotic derivation and numerical validation

The objective of this paper is to derive, from the Navier-Stokes equations in a shallow domain,a new bidimensional shallow water model able to filter the high frequency oscillations that are produced, when the Reynolds number is increased, in turbulent ows. With this aim, the non- dimensional Navier-Stokes equations are time-averaged, and then asymptotic analysis techniques have been used as in our previous works. The small non-dimensional parameter considered, "e", is the quotient between the typical depth of the basin and the typical horizontal length of the domain; and it is studied what happens when "e" becomes small. Once the new model has been justified, by the method of asymptotic expansions, we perform some numerical experiments. The results of these experiments con rm that this new model is able to approximate analytical solutions of Navier-Stokes equations with more accuracy than classical shallow water models, when high frequency oscillations appear. To reach a given accuracy, the time step for the new model can be much larger (even four hundred times larger) than the time step required for the classical models

Un modelo de aguas someras con dependencia explícita de la profundidad

En este trabajo estudiamos las ecuaciones bidimensionales de Eurler en un dominio con poca profundidad. Con este propósito, se introduce un pequeño parámetro adimensional ε relacionado con la profundidad y se aplica la técnica de los desarrollos asintóticos para estudiar lo que sucede cuando ε se hace pequeño. Se obtiene un modelo para ε pequeño que, tras deshacer el cambio de variable, en el dominio original, proporciona un modelo de aguas someras que incluye los efectos de un fondo no constante y cuya velocidad horizontal depende de z a través de la vorticidad (cuando ´esta no es nula). Esta dependencia hacen que el modelo obtenido sea novedoso respecto a los modelos de aguas someras que pueden encontrarse actualmente en la literatura. Además, este modelo se obtiene sin necesidad de imponer hipótesis a priori sobre la velocidad o la presión. El nuevo modelo es capaz de aproximar las soluciones de las ecuaciones de Euler con dependencia en z (reobteniendo el mismo perfil de velocidades), mientras que el modelo clásico únicamente calcula la velocidad media en la vertical.Ministerio de Educación y Cienci

Numerical Behaviour of a New LES Model with Nonlinear Viscosity

Preprint submitted to Elsevier[Abstract] The objective of this paper is to present a new Large Eddy Simulation (LES) model obtained by filtering a generalized version of the Navier–Stokes equations with nonlinear viscosity. This new model is a generalization of the model introduced in Rodríguez and Taboada-Vázquez (2017). The new LES model, in which viscosity has been substituted by a nonlinear function of the strain rate tensor, has been implemented and validated using FreeFem++ codes. The numerical predictions have been compared with analytical solutions of the Navier–Stokes equations and it was found that the present model provides a more accurate approximation of the exact solution than that obtained by Direct Numerical Simulation (DNS) of the Navier–Stokes equations, even using a coarser mesh. The model has also been validated by studying the unsteady flow over a backward-facing step. In this case, our numerical predictions have been compared with the experimental measurements reported by Armaly et al. (1983) and the numerical results obtained by Chacón and Lewandowski (2014). The new model performs satisfactorily in predicting these flows too.Ministerio de Economía y Competitividad; MTM2016-78718-

Asymptotic Analysis of a Thin Fluid Layer Flow Between Two Moving Surfaces

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] In this paper we study the behavior of an incompressible viscous fluid moving between two very close surfaces also in motion. Using the asymptotic expansion method we formally justify two models, a lubrication model and a shallow water model, depending on the boundary conditions imposed. Finally, we discuss under what conditions each of the models would be applicable.This work has been partially supported by Ministerio de Economía y Competitividad of Spain, under grant MTM2016-78718-P with the participation of FEDER, and the European Union's Horizon 2020 Research and Innovation Programme, under the Marie Sklodowska-Curie Grant Agreement No 823731 CONMECH. Funding for open access charge: Universidade da Coruña/CISU

Un modelo unidimensional de flujo sanguíneo obtenido mediante el método de desarrollos asintóticos

En este trabajo presentamos un modelo unidimensional del movimiento de un fluido newtoniano a través de un tubo elástico no necesariamente rectilíneo. En particular, el modelo obtenido es aplicable al estudio del flujo sanguíneo. Para obtener el modelo propuesto explotamos el hecho de que el área de la sección transversal del tubo es mucho menor que su longitud, lo que nos permitir´a introducir un pequeño parámetro adimensional y utilizar el método de desarrollos asintóticos. El modelo así obtenido incorpora un nuevo término dependiente de la curvatura de la línea media del tubo, que no hemos encontrado en la literatura, y que se opone al avance del fluido.Ministerio de Educación y Cienci

VERTICAL TRANSMISSION OF DENGUE VIRUS IN Aedes aegypti COLLECTED IN PUERTO IGUAZÚ, MISIONES, ARGENTINA

A finding of vertical transmission of the DEN 3 virus in male specimens of Aedes aegypti, collected in the 2009 fall-winter period, in Puerto Iguazú city, Misiones, Argentina, using the RT-PCR technique in a 15-specimen pool is reported. This result is analyzed within the context of the epidemiological situation of Argentina's northeast border.Se comunica el hallazgo de transmisión vertical de virus DEN 3 en ejemplares machos de Aedes aegypti, capturados en otoño-invierno de 2009, en la ciudad de Puerto Iguazú, Misiones, Argentina, utilizando la técnica de RT-PCR en un pool de 15 ejemplares. Se analiza este resultado en el contexto de la situación epidemiológica de la frontera nordeste de Argentina

Physiotherapy for freezing of gait in Parkinson's disease: a systematic review and meta-analysis

Introduction. Freezing of gait (FOG) is one of the most severe symptoms associated with Parkinson's disease (PD). Physiotherapy treatment could be an effective strategy for treating FOG, but no systematic review has been carried out in this regard. Aim. To identify the characteristics, methodological quality, and main outcomes of the studies that have analyzed the effects of physiotherapy interventions in FOG up to date, by performing a systematic review and a meta-analysis. Patients and methods. Four electronic databases were searched in order to find randomized controlled trials that provided information regarding the effects of any kind of physiotherapy treatment on FOG. The methodological quality of the included investigations was assessed by means of the PEDro scale. Results. Twelve studies were identified for inclusion into the qualitative analysis, with four randomized controlled trials included in the final meta-analysis. The quality of the trials was generally good. Those physiotherapy modalities including cues were more effective for treating FOG than traditional physiotherapy approaches. The meta-analysis indicated that physiotherapy interventions had a significantly greater impact on FOG than control comparisons. Conclusions. Physiotherapy treatment, especially those modalities including visual and auditory cueing, should be prescribed to PD patients with FOG. Future studies including PD patients with cognitive impairment and FOG objective measurement tools are need to complete the existing scientific evidence

Response of Three Different Viruses to Interferon Priming and Dithiothreitol Treatment of Avian Cells

We have previously shown that the replication of avian reovirus (ARV) in chicken cells is much more resistant to interferon (IFN) than the replication of vesicular stomatitis virus (VSV) or vaccinia virus (VV). In this study, we have investigated the role that the double-stranded RNA (dsRNA)-activated protein kinase (PKR) plays in the sensitivity of these three viruses toward the antiviral action of chicken interferon. Our data suggest that while interferon priming of avian cells blocks vaccinia virus replication by promoting PKR activation, the replication of vesicular stomatitis virus appears to be blocked at a pretranslational step. Our data further suggest that the replication of avian reovirus in chicken cells is quite resistant to interferon priming because this virus uses strategies to downregulate PKR activation and also because translation of avian reovirus mRNAs is more resistant to phosphorylation of the alpha subunit of initiation factor eIF2 than translation of their cellular counterparts. Our results further reveal that the avian reovirus protein sigmaA is able to prevent PKR activation and that this function is dependent on its double-stranded RNA-binding activity. Finally, this study demonstrates that vaccinia virus and avian reovirus, but not vesicular stomatitis virus, express/induce factors that counteract the ability of dithiothreitol to promote eIF2 phosphorylation. Our data demonstrate that each of the three different viruses used in this study elicits distinct responses to interferon and to dithiothreitol-induced eIF2 phosphorylation when infecting avian cellsThe Spanish Ministerio de Economía y Competitividad provided funding to Javier Benavente and José Martínez-Costas under grant numbers BFU2010-22228 and BFU2013-43513-R. Support was also provided by the Xunta de Galicia (CN 2012/018). Irene Lostalé-Seijo was a recipient of a predoctoral FPU fellowship (Ministerio de Educación y Ciencia) and a Research Fellowship (Bolsa de Investigación; Deputación Provincial da Coruña)S

Interferon induction by avian reovirus

We have previously shown that the replication of avian reovirus (ARV) in chicken embryo fibroblasts (CEF) is more resistant to the antiviral action of interferon (IFN) than the replication of vesicular stomatitis virus (VSV) or vaccinia virus (VV). In this study we examined the capacity of these three viruses to induce the expression of IFN when infecting avian cells. Efficient expression of both type-α and type-β IFNs, as well as of the double-stranded RNA (dsRNA)-activated protein kinase (PKR), takes place in ARV-infected CEF, but not in cells infected with VSV or VV. PKR expression is not directly induced by ARV infection, but by the IFN secreted by ARV-infected cells. IFN induction in ARV-infected cells requires viral uncoating, but not viral gene expression, a situation similar to that reported for apoptosis induction by ARV-infected cells. However, our results demonstrate that IFN induction by ARV-infected CEF occurs by a caspase-independent mechanismThis work was funded by grants from the Spanish Ministerio de Economia y Competitividad (BFU2010-22228 and BFU2013-43513-R) and from the Xunta de Galicia (CN 2012/018). I.L.S. was a recipient of a predoctoral FPU fellowship (Ministerio de Educación y Ciencia) and a Research Fellowship (Bolsa de Investigación) (Deputación Provincial da Coruña)S

Benefits of Pilates in Parkinson’s Disease: A Systematic Review and Meta-Analysis

[ES] Pilates may be a beneficial method of exercise for people with Parkinson’s disease (PD). However, no studies have critically reviewed the scientific evidence in this regard. The purpose of this study was to conduct a systematic review and meta-analysis on the effectiveness of Pilates as a rehabilitation strategy for PD. A systematic search of the electronic databases PubMed, PEDro, Scopus, and SPORTDiscus was conducted to identify studies related to the effect of Pilates on PD. The search timeframe ranged from the inception of each database to March 2019. The search resulted in the identification of four randomized controlled trials (RCTs) and four non-RCT studies. The methodological quality of the investigations ranged from poor to fair. The descriptive analysis of the eight investigations showed that Pilates resulted in beneficial effects on fitness, balance and functional autonomy. A subsequent meta-analysis on the four RCTs indicated that Pilates was more effective than traditional training programmes in improving lower limb function. Pilates can be safely prescribed for people with mild-to-moderate PD. Preliminary evidence indicates that its practice could have a positive impact on fitness, balance and physical function. Its benefits on lower-body function appear to be superior to those of other conventional exercises. Future randomized studies with greater samples are needed to confirm these observations