Assimetrias do crânio de javalis (Sus scrofa LINNAEUS, 1758)

Organisms can develop different kinds of asymmetry when deviations from expected perfect symmetry occur. Among others are fluctuating asymmetry (FA) and directional asymmetry (DA). FA represents small random differences between corresponding parts on the left and right sides of an individual in bilaterally paired structures. It is thought that FA reflects an organism's ability to cope with genetic and environmental stress during growth. DA occurs whenever one side on the plane of symmetry develops more than the other side, and has a genetic component. In this research, we examined the expression of morphological symmetry in 38 skulls of different age groups of wild boar (Sus scrofa), on their ventral aspect, using two-dimensional coordinates of 27 landmarks. Analyses showed the presence of significant FA and DA in the entire sample, detecting also distinctive differences between age groups. The obtained results show that the shape differences in different age groups could reasonably be a consequence of a response to environmental factors for FA and a masticatory lateralization for DA.Os organismos podem desenvolver diferentes tipos de assimetria quando ocorrem desvios da pefeita simetria esperada. Entre os diversos tipos de assimetria existentes duas merecem especial destaque: a flutuante (AF) e a directional (AD). A AF é representada por pequenas diferenças casuais entre as partes correspondents das laterais direita e esquerda de um indivíduo em estruturas pareadas bilateralmente; acredita-se que elas reflitam a habilidade de um organismo adaptar-se a fatores estressantes genéticos e ambientais observados durante o seu crescimentos. A AD ocorre quando um lado da assimetria plana desenvolve-se mais do que o outro e há um componente genético. No presente trabalho foi analisada a expresssão da simetria morfológica de 38 crânios de diferentes grupos etários de javalis (Sus scrofa), nos seus aspectos ventrais, com o emprego de duas coordenadas dimensionais de 27 pontos anatômicos homólogos. As análises efetuadas revelaram a existência de valores significantes de AF e AD em toda a amostra trabalhada, detectando inclusive diferenças entre os grupos etários. Os resultados obtidos demonstraram que as diferentes formas observadas nos diferentes grupos etários podem ser consequência de uma resposta a fatores ambientais para a AF e a lateralização da mastigação para a AD

A new equilibrated residual method improving accuracy and efficiency of flux-free error estimates

This paper presents a new methodology to compute guaranteed upper bounds for the energy norm of the error in the context of linear finite element approximations of the reaction–diffusion equation. The new approach revisits the ideas in Parés et al. (2009) [6, 4], with the goal of substantially reducing the computational cost of the flux-free method while retaining the good quality of the bounds. The new methodology provides also a technique to compute equilibrated boundary tractions improving the quality of standard equilibration strategies. The zeroth-order equilibration conditions are imposed using an alternative less restrictive form of the first-order equilibration conditions, along with a new efficient minimization criterion. This new equilibration strategy provides much more accurate upper bounds for the energy and requires only doubling the dimension of the local linear systems of equations to be solved.Postprint (author's final draft

Fecal incontinence: the quality of reported randomized, controlled trials in the last ten years.

This study was designed to analyze the characteristics and the quality of reporting of randomized, controlled trials published during the last ten years on fecal incontinence

Goal-oriented h-adaptivity for the Helmholtz equation: error estimates, local indicators and refinement strategies

The final publication is available at Springer via http://dx.doi.org/10.1007/s00466-010-0557-2This paper introduces a new goal-oriented adaptive technique based on a simple and effective post-process of the finite element approximations. The goal-oriented character of the estimate is achieved by analyzing both the direct problem and an auxiliary problem, denoted as adjoint or dual problem, which is related to the quantity of interest. Thus, the error estimation technique proposed in this paper would fall into the category of recovery-type explicit residual a posteriori error estimates. The procedure is valid for general linear quantities of interest and it is also extended to non-linear ones. The numerical examples demonstrate the efficiency of the proposed approach and discuss: (1) different error representations, (2) assessment of the dispersion error, and (3) different remeshing criteria.Peer ReviewedPostprint (author's final draft

Correlating magnetic fabrics with finite strain : comparing results from mudrocks in the Variscan and Appalachian Orogens

New magnetic anisotropy data from Variscan mudstones collected in the Cantabrian Arc, N Spain constrain the corresponding strain (shortening). The results are based on our previous study of mudrocks from the Valley and Ridge Province (Appalachians) where independent strain quantification of pencil structures permitted a correlation between magnetic fabric and tectonic strain. An exponential relationship between the AMS shape parameter T and tectonic shortening was found for the interval of 10-25% shortening: shortening (%)=17*exp(T), relationship that appears to be supported by tectonic strains up to 40%. The T parameter describes the shape of the magnetic susceptibility ellipsoid, which in pelitic rocks appears more sensitive to strain than the degree of anisotropy parameter P (or P'). In mudrocks from the Cantabrian Arc a positive correlation between T parameter and deformation intensity, reflected by cleavage domains spacing, is observed. Using the above relationship, we estimate the range of tectonic shortening for the Cantabrian mudstones. The correlation between strain and AMS offers a robust estimate of strain magnitude of 10-40% in weakly to moderately deformed clay-rich rocks, where other strain indicators are often lacking or are poorly preserved