Dimension dependent hypercontractivity for Gaussian kernels

We derive sharp, local and dimension dependent hypercontractive bounds on the Markov kernel of a large class of diffusion semigroups. Unlike the dimension free ones, they capture refined properties of Markov kernels, such as trace estimates. They imply classical bounds on the Ornstein-Uhlenbeck semigroup and a dimensional and refined (transportation) Talagrand inequality when applied to the Hamilton-Jacobi equation. Hypercontractive bounds on the Ornstein-Uhlenbeck semigroup driven by a non-diffusive L\'evy semigroup are also investigated. Curvature-dimension criteria are the main tool in the analysis.Comment: 24 page

Linfagioma Quístico Mediastínico: Um Caso Clínico

Os autores referem o caso clínico de uma criança de 2 anos, sexo masculino e raça negra, que apresentava estridor desde os 2 meses de idade e na qual foi diagnosticado um linfangioma quístico mediastínico. A remoção cirúrgica levou ao desaparecimento da sintomatologia. É feita uma revisão teórica sobre esta temática abrangendo aspectos epidemiológicos, clínicos e terapêuticos. Salientam a importância dos diferentes exames complementares para o diagnóstico definitivo

Efeito da pré-embebição na germinação de sementes de coentro (Coriandro sativum L.).

Este trabalho foi realizado com o objetivo de avaliar o comportamento fisiológico das sementes de coentro submetidas a diferentes períodos de imersão em água, visando acelerar e uniformizar o processo germinativo

Uniform convergence to equilibrium for granular media

We study the long time asymptotics of a nonlinear, nonlocal equation used in the modelling of granular media. We prove a uniform exponential convergence to equilibrium for degenerately convex and non convex interaction or confinement potentials, improving in particular results by J. A. Carrillo, R. J. McCann and C. Villani. The method is based on studying the dissipation of the Wasserstein distance between a solution and the steady state

Biomechanical Study of the Vestibular System of the Inner Ear Using a Numerical Method

The inner ear has two main parts, the cochlea, dedicated to hearing, and the vestibular system, dedicated to balance. Dizziness and vertigo are the main symptoms related to vestibular disorders, which commonly affects older people. In order to eliminate these symptoms a vestibular rehabilitation is performed; this consists in a range of movements of the head, known as maneuvers, performed by a clinical professional. This procedure does not always work as expected. The aim of this work is to contribute to a better understanding on how the vestibular system works. This knowledge will help in the development of new techniques that will facilitate a more efficient rehabilitation. In order to achieve that goal, a three-dimensional numerical model of the vestibular system, containing the fluids which promote the body balance, was constructed. The vestibular components will be discretized using the finite element method and the fluid flow will be analyzed using the Smoothed Particle Hydrodynamics The results obtained with the numerical model of the semicircular canal built to study the rehabilitation process are presented and compared with other authors. The solution achieved is similar with literature.info:eu-repo/semantics/publishedVersio

Study of the middle ear behavior considering the presence of fluid

O objetivo deste trabalho foi estudar a influência de diferentes fluidos dentro e fora da cavidade timpânica no comportamento biomecânico do ouvido médio. O modelo computacional 3 D da cadeia tímpano‐ossicular foi construído através de imagens de tomografia axial computorizada (TAC). Após a construção do modelo da cadeia tímpano‐ossicular, para a parte interna da membrana timpânica foi criada a caixa timpânica, que inclui toda a cadeia ossicular, e para a parte externa da membrana foi criada uma passagem, simulando o canal auditivo externo. A discretização do modelo foi feita utilizando o método dos elementos finitos, com base no software ABAQUS. As propriedades mecânicas foram extraídas de trabalhos anteriores. Foram obtidos os deslocamentos do umbo e de um ponto central da platina do estribo, para um nível de pressão sonora de 105 dB aplicada na membrana timpânica, comparando a cadeia tímpano‐ossicular e os diferentes níveis de pressão externa e interna do ouvido médio (fluido líquido e fluido gasoso). Os resultados demonstram que o comportamento biomecânico do ouvido médio é diferente para os diferentes níveis de pressões testadas neste modelo. Quando utilizada uma pressão de fluido líquido, os deslocamentos são de amplitude inferior quando comparados com os resultados obtidos com pressão de ar.The objective of this work is to study the influence of different fluids of the tympanic cavity into the biomechanical behavior of the middle ear. The 3 D computer model of the tympanic ossicular chain was built using images from computed tomography (CT). After construction of the tympanic ossicular chain model, it was adapted the simulation by placing the passage to the external auditory canal and to the tympanic cavity. The discretization of the model was made using the finite element method based on ABAQUS software. The mechanical properties were extracted from previous works. The umbo and the stapes footplate displacements, for a sound pressure level of 105 dB applied in tympanic membrane were obtained, comparing the tympanic ossicular chain and the different levels of external and internal pressure in the middle ear (liquid and air). The results demonstrate that the biomechanical behavior of the middle ear is different for different levels of pressure tested in this model. When using liquid, displacements are of lower amplitude when compared with the results obtained with air.Peer Reviewe