652 research outputs found

    Dimension dependent hypercontractivity for Gaussian kernels

    Get PDF
    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

    Tumour-initiating activities on mouse skin of dihydrodiols derived from benzo[a]pyrene.

    Get PDF
    Three dihydrodiols that are metabolites of benzo[a]pyrene and benzo[a]-pyrene itself have been tested in a comparative experiment for their activities as initiators of tumours in mouse skin. A single application (25 mug) of 4,5-dihydro-4,5-dihydroxybenzo[a]pyrene, of 7,8-dihydro-7,8-dihydroxybenzo[a]pyrene, of 9,10-dihydro-9,10-dihydroxybenzo[a]pyrene, or of benzo[a]pyrene was made to the shaved dorsal skin of adult female CDI mice; this was followed 2 weeks later by multiple thrice-or twice-weekly applications (1 mug) of 12-O-tetradecanoyl-phorbol-13-acetate as promoting agent. A control group of 30 mice received the promoting agent alone. The experiments were terminated 52 weeks after initiation. At this stage, all the groups contained mice bearing skin papillomas, some of which had progressed to malignancy. Quantitatively the results show that the 7,8-dihydrodiol is almost as active an initiator of mouse skin tumours as benzo[a]pyrene itself; the 4,5- and 9,10-dihydrodiols were significantly less active. The significance of these results is discussed in relation to the hypothesis that diol-epoxides are important in the metabolic activation of polycyclic hydrocarbons like benzo[a]pyrene

    Linfagioma Quístico Mediastínico: Um Caso Clínico

    Get PDF
    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

    Outer retinal layers as predictors of visual acuity in retinitis pigmentosa: a cross-sectional study

    Get PDF
    PURPOSE: To evaluate the integrity of the outer retinal layers-outer nuclear layer (ONL), external limiting membrane (ELM), ellipsoid (EZ), and interdigitation band (IZ)-using spectral-domain optical coherence tomography and estimate their effect on visual acuity in retinitis pigmentosa (RP). METHODS: A cross-sectional study was performed in the Ophthalmology Department of Hospital de Braga, Portugal. Patients with RP followed in the Hospital de Braga during January to August 2017 were included. Exclusion criteria were lack of data, macular edema due to RP, and concomitant retinal, optic nerve, or corneal disease that could interfere with visual acuity. Age, sex, time from diagnosis, phakic status, ONL thickness, and presence or absence of foveal ELM, EZ, and IZ were correlated to the best-corrected visual acuity (BCVA). RESULTS: Forty-eight eyes were analyzed. There was a strong and positive correlation in BCVA between both eyes (p < .001*). ONL thickness was decreased in 95.8%. The EZ was the most absent layer (79.2%), followed by IZ (70.8%) and ELM (45.8%). A positive family history (p = .04*) and increased time from diagnosis (p = .037*) correlated with worse BCVA. A thicker ONL (p = .001*) and the presence of subfoveal ELM (p < .001*), EZ (p < .001*), and IZ (p = .02*) are correlated with better BCVA. There was a strong and positive correlation between the number of layers affected and a lower BCVA (p < .001). The presence of EZ was a significant predictor of BCVA (p = .02*). CONCLUSIONS: The status of the outer retinal layers seems to influence BCVA. The status of the EZ was the most important predictor of BCVA but the ONL, ELM, and IZ may have a cumulative effect in the progression of visual loss.info:eu-repo/semantics/publishedVersio

    Validade de um procedimento para indução de frustração

    Get PDF
    OBJECTIVE: To test a reliable and easily administered frustration-induction procedure for experimental research. METHOD: One hundred volunteers (81 women, mean age ± SD 34.2 ± 8 years) physically and psychiatrically healthy submitted to the frustration induction procedure were prevented from reaching reward level scores. Subjective aggressiveness feelings related to frustration were self-rated in a 13-item visual analogue scale before and after the procedure. RESULTS: Significant increases in aggressiveness-related feelings were detected in 12 of the 13 items. This was consistent with the observed overt behavior of the subjects during the task. CONCLUSIONS: The frustration-induction procedure is a simple, easy to administer frustration-induction procedure that can be used in experimental studies in normal subjects.OBJETIVO: Testar um procedimento de indução de frustração confiável e de simples aplicação para a pesquisa experimental. MÉTODO: Cem voluntários (81 mulheres, idade média ± DP 34,2 ± 8 anos), física e psiquiatricamente saudáveis, submetidos ao procedimento de indução de frustração, foram impedidos de atingir escores de recompensa. Os sentimentos de agressividade subjetivos relacionados à frustração foram autoclassificados em um escala analógica visual de 13 itens antes e após o procedimento. RESULTADOS: Foram detectados aumentos significativos nos sentimentos relacionados à agressividade em 12 dos 13 itens. Isto foi consistente com o comportamento manifestado pelos indivíduos e observado durante a tarefa. CONCLUSÕES: O procedimento de indução de frustração é simples, facilmente aplicável e que pode ser utilizado em estudos experimentais com indivíduos normais.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    FRIEDMAN E O MONETARISMO: A VELHA TEORIA QUANTITATIVA DA MOEDA E A MODERNA ESCOLA MONETARISTA

    Get PDF
    The paper aims to present the evolution of the Quantitative Theory of Money from its initial formulation to Friedman's final proposal. It aims also to analyze the principles of Economic Policy resulting from this reinterpretation of Quantitative Theory elaborated by Friedman and other monetarist economists.The paper aims to present the evolution of the Quantitative Theory of Money from its initial formulation to Friedman's final proposal. It aims also to analyze the principles of Economic Policy resulting from this reinterpretation of Quantitative Theory elaborated by Friedman and other monetarist economists

    The human otitis media with effusion: a numerical-based study

    Get PDF
    Otitis media is a group of inflammatory diseases of the middle ear. Acute otitis media and otitis media with effusion (OME) are its two main types of manifestation. Otitis media is common in children and can result in structural alterations in the middle ear which will lead to hearing losses. This work studies the effects of an OME on the sound transmission from the external auditory meatus to the inner ear. The finite element method was applied on the present biomechanical study. The numerical model used in this work was built based on the geometrical information obtained from The visible ear project. The present work explains the mechanisms by which the presence of fluid in the middle ear affects hearing by calculating the magnitude, phase and reduction of the normalized umbo velocity and also the magnitude and phase of the normalized stapes velocity. A sound pressure level of 90 dB SPL was applied at the tympanic membrane. The harmonic analysis was performed with the auditory frequency varying from 100 Hz to 10 kHz. A decrease in the response of the normalized umbo and stapes velocity as the tympanic cavity was filled with fluid was obtained. The decrease was more accentuated at the umbo.info:eu-repo/semantics/publishedVersio
    corecore