Metabolički i genski poremećaji – pregled mehanizama toksičnosti i genotoksičnosti arsena i olova

Urbanisation and industrialisation are on the rise all over the world. Environmental contaminants such as potentially toxic elements (PTEs) are directly linked with both phenomena. Two PTEs that raise greatest concern are arsenic (As) and lead (Pb) as soil and drinking water contaminants, whether they are naturally occurring or the consequence of human activities. Both elements are potential carcinogens. This paper reviews the mechanisms by which As and Pb impair metabolic processes and cause genetic damage in humans. Despite efforts to ban or limit their use, due to high persistence both continue to pose a risk to human health, which justifies the need for further toxicological research.Urbanizacija i industrijalizacija su u porastu u cijelome svijetu. S obama ovim fenomenima izravno su povezana zagađivala iz okoliša, poput potencijalno toksičnih elemenata (PTE). Dva elementa koja izazivaju najveću zabrinutost su arsen (As) i olovo (Pb) u tlu i vodi, bilo da su tamo došli prirodnim putem ili zbog ljudske djelatnosti. Oba su i potencijalno kancerogena. U ovom preglednom radu razmatraju se mehanizmi kojima As i Pb ugrožavaju metaboličke procese i izazivaju oštećenja genoma. Unatoč zabranama i naporima da se ograniči njihovo korištenje, oba su elementa perzistentna u okolišu i predstavljaju rizik za ljudsko zdravlje, zbog čega je potrebno nastaviti s njihovim toksikološkim istraživanjima

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-

Changes in the morphological characteristics of potato plants attributed to seasonal variability

The development of a potato crop differs according to the environmental conditions and growing season of an area. Periods of high temperatures and drought have been frequent in recent years, and this has affected crops worldwide. The effect of meteorological factors on the plant morphology of potato cultivars growing in A Limia was analyzed for three consecutive years. The crop cycle with the highest temperatures and least accumulated rainfall (2016) showed plants with a higher number of leaflets, which were shorter in length. The crop cycle (2014) with a lower temperature and more rainfall had the tallest plants, the highest degree of flowering, fewer pairs of leaflets and the highest length of the floral peduncle. Kennebec and Fontane were the varieties that showed the least variability in morphological characteristics during the seasons analyzed. Considering the meteorological and morphological data, a principal component analysis was carried out, which explained 80.1% of the variance of the data. Spearman rank correlations showed higher significant coefficients between the temperature and foliar characteristics. The leaf size of plants was estimated using a multiple linear regression analysis, which included the mean temperature, explaining 64% of the variability of the data.Xunta de Galicia | Ref. 2014/2020-FEADE

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

Avaliação da qualidade e rotulagem do mel: adequação à nova legislação

Só está disponível o resumo.Avaliação da qualidade e rotulagem do mel: adequação à nova legislação

Can isotopes be used as lead tracers in shooting-range soils?

Lead isotopes have been widely used to assess the sources of Pb in the soil environment since lead isotopes ratios have a specific signature that allows us to use them as environmental tracers. However, some lead sources are difficult to be identified. This article contains the lead isotope data from soils and shot pellets collected in an abandoned shooting range (NW Spain). Twelve soil and three-shot pellet samples were randomly collected and analyzed using MC-ICP-MS. The isotope ratios are shown, and analyses proved that Pb originated predominantly from the used shot pellets. Contaminated soils exhibited an isotopic composition (206Pb/207Pb, 208Pb/204Pb, 206Pb/204Pb and 208Pb/206Pb) close to some shot pellets from different manufacturers. These results offer new, valuable data for other researchers working on lead contamination research and the identification sources of Pb for adjacent areas to shooting-range facilities and for wildlife ecotoxicology. Still, the use of several ammunitions derived from different sources, such as recycled Pb, showed that it is hard to identify the lead source and these kinds of facilities.Ministerio de Economía y Competitividad | Ref. CGL2013-45494-RFundação para a Ciência e Tecnologia | Ref. UIDB/04423/2020Fundação para a Ciência e Tecnologia | Ref. UIDP/04423/2020Fundação para a Ciência e Tecnologia | Ref. CEECIND/03794/2017Ministerio de Ciencia e Innovación | Ref. IJC2020-044197-

Incidencia de las concentraciones del polen de Urticaceae en la atmósfera de Vigo (1995 - 1997)

RoDRÍcsUEZ-RMO, E. J., Salo, M. C. & JATO, M. V. 2000. beidencia de las concentraciones del polen de Urticaceae en la atmósfera de Vigo (1995-¡997). Bar Complurensis 24: 89-lOO. En el presente trabajo, ha sido estudiado durante un período de tres años el contenido polínico de Urticaeeae en la atmósfera de Vigo Las especies presentes en el área de estudio son ljj-tic-a dioica, U/-tic-a arens, Uítico membí-onacea y Parierajia offícina/is. fin captador LANZONI VPPS 2000 ha sido utilizado para capturar los granos de polen desde ¡995 hasta ¡997 Urticaceae es el taxon mas abundante y su porcentaje frente al total de polen anual es el mayor (21 al 25%). La cantidad de polen de U/rica recogido a lo largo de un año es como media de 9.464 granos, con un período de polinización muy largo desde Febrero hasta Septiembre (manteniéndose en la atmósfera 200 días). Asimismo, a lo largo del día los máximos de concentración tienen lugar entre las ¡2 y las ¡4horas. Finalmente se ha realizado un análisis estadístico para poner de manifiesto la posible correlación con los principales paránietros meteorológicos.RoDRÍcsUEZ-RMO, E. J., Salo, M. C. & JATO, M. V. 2000. beidencia de las concentraciones del polen de Urticaceae en la atmósfera de Vigo (1995-¡997). Bar Complurensis 24: 89-lOO. En el presente trabajo, ha sido estudiado durante un período de tres años el contenido polínico de Urticaeeae en la atmósfera de Vigo Las especies presentes en el área de estudio son ljj-tic-a dioica, U/-tic-a arens, Uítico membí-onacea y Parierajia offícina/is. fin captador LANZONI VPPS 2000 ha sido utilizado para capturar los granos de polen desde ¡995 hasta ¡997 Urticaceae es el taxon mas abundante y su porcentaje frente al total de polen anual es el mayor (21 al 25%). La cantidad de polen de U/rica recogido a lo largo de un año es como media de 9.464 granos, con un período de polinización muy largo desde Febrero hasta Septiembre (manteniéndose en la atmósfera 200 días). Asimismo, a lo largo del día los máximos de concentración tienen lugar entre las ¡2 y las ¡4horas. Finalmente se ha realizado un análisis estadístico para poner de manifiesto la posible correlación con los principales paránietros meteorológicos