653 research outputs found
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 QuĂstico MediastĂnico: Um Caso ClĂnico
Os autores referem o caso clĂnico 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 quĂstico mediastĂnico. A remoção cirĂşrgica levou ao desaparecimento da sintomatologia. É feita uma revisĂŁo teĂłrica sobre esta temática abrangendo aspectos epidemiolĂłgicos, clĂnicos e terapĂŞuticos. Salientam a importância
dos diferentes exames complementares para o diagnĂłstico 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 fisiolĂłgico das sementes de coentro submetidas a diferentes perĂodos de imersĂŁo 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
A computational framework to simulate the endolymph flow due to vestibular rehabilitation maneuvers assessed from accelerometer data
Vertiginous symptoms are one of the most common symptoms in the world, therefore investing in new ways and therapies to avoid the sense of insecurity during the vertigo episodes is of great interest. The classical maneuvers used during vestibular rehabilitation consist in moving the head in specific ways, but it is not fully understood why those steps solve the problem. To better understand this mechanism, a three-dimensional computational model of the semicircular ducts of the inner ear was built using the finite element method, with the simulation of the fluid flow being obtained using particle methods. To simulate the exact movements performed during rehabilitation, data from an accelerometer were used as input for the boundary conditions in the model. It is shown that the developed model responds to the input data as expected, and the results successfully show the fluid flow of the endolymph behaving coherently as a function of accelerometer data. Numerical results at specific time steps are compared with the corresponding head movement, and both particle velocity and position follow the pattern that would be expected, confirming that the model is working as expected. The vestibular model built is an important starting point to simulate the classical maneuvers of the vestibular rehabilitation allowing to understand what happens in the endolymph during the rehabilitation process, which ultimately may be used to improve the maneuvers and the quality of life of patients suffering from vertigo.info:eu-repo/semantics/publishedVersio
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
Cultivo de hortaliças em várzeas amazônicas: uma técnica tradicional para evitar a água e a umidade.
A AmazĂ´nia compreende a maior extensĂŁo de floresta tropical Ăşmida do planeta, com área de 6.099.788 km², distribuĂda nos territĂłrios do Brasil (58,8%), Peru (13%), ColĂ´mbia (7,6%), Venezuela (6,5%), BolĂvia (5,5%), Guiana (3,1%), Suriname (2,5%), Equador (1,6%) e Guiana Francesa (1,4%) (RAISG, 2015). A regiĂŁo do Brasil inserida na AmazĂ´nia continental tem superfĂcie original estimada em 3.587.052 km², abrangendo os estados do Acre, Amapá, Amazonas, Pará, RondĂ´nia e Roraima, sendo definida como zona de ocorrĂŞncia da HilĂ©ia (Pandolfo, 1994). Mas, em 1953, a abrangĂŞncia legal da AmazĂ´nia brasileira foi estabelecida pela Lei nÂş 1.806, quando foram incorporados tambĂ©m os territĂłrios dos estados de Tocantins, Mato Grosso e parte do MaranhĂŁo (oeste do meridiano 44Âş) (Brasil, 2016). O bioma amazĂ´nico Ă© constituĂdo por distintos ecossistemas, porĂ©m dois sĂŁo mais correntes tanto no meio acadĂŞmico quanto para o pĂşblico em geral: terra firme e várzea.bitstream/item/170310/1/4900.pd
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