60 research outputs found
Plemorphic Adenoma of the Infratemporal Space: A New Case Report
Plemorphic adenoma is a frequent benign tumor of the major salivary glands. It could also develop from accessory salivary glands. We are reporting an extremely rare case of pleomorphic adenoma developing from the infratemporal space. The final diagnosis was based on histological confirmation. The treatment was mainly a complete resection via an anterior transmaxillary approach. Diagnosis, clinical behaviour, and treatment of pleomorphic adenoma of the infra-temporal space are reviewed from the literature
Métastases intramédulaires d’un adénocarcinome pulmonaire: à propos d’un cas
Les métastases de la moelle épinière sont extrêmement rares. Elles surviennent chez 0,1 à 0,4% des patients cancéreux et représentent 1% detoutes les tumeurs de la colonne vertébrale et 1-3% des tumeurs intramédullaires. Le cancer du poumon est le primitif le plus fréquent. Nousrapportons le cas d’un patient de 51 ans, suivi pour un adénocarcinome pulmonaire et qui après la 1ère cure de chimiothérapie a développé des métastases intramédullaires et cérébrales. Une radiothérapie sur la moelle et le cerveau associée à une corticothérapie par voie générale ont été débutées. Le patient est décédé 3 mois après la survenue des métastases intramédullaires. A travers ce nouveau cas de métastases intarmédullaires d’un adénocarcinome pulmonaire et revue de la littérature, les auteurs insistent sur leur rareté ainsi que sur ses difficultés diagnostiques et thérapeutiques
Le syndrome des jambes sans repos : fréquence et facteurs de risque chez l’hémodialysé
Le syndrome des jambes sans repos (SJSR) ou syndrome d'impatience musculaire est un trouble moteur caractérisé par des sensations désagréables dans les jambes. Les causes sont mal connues et sa fréquence est estimée entre 25% et 75% chez les hémodialysés. Il s'agit d'une étude transversale monocentrique menée au centre d'hémodialyse du CHU Hassan II de Fès (hôpital Al Ghassani) entre décembre 2012 et janvier 2013. Nous avons défini le syndrome de jambes sans repos selon la définition de l'international restless legs study group de 2003 reposant sur 4 critères essentiels au diagnostic. L'international restless legs syndrome scale (IRLES) a été coté par un même néphrologue pour mesurer la sévérité du syndrome des jambes sans repos. 84 hémodialysés ont répondu au questionnaire avec 41,7% de cas de SJSR dont 6,6% de formes graves. Nous avons retrouvé une association entre le SJSR et la carence martiale p(0,018), la néphropathie initiale p(0,041), l'HTA p(0,026) et le sexe féminin p(0,024). Dans notre série, il ressort que la carence martiale et l'HTA sont les principaux facteurs de risque modifiables de ce syndrome chez nos patients. Les facteurs traditionnels comme le tabagisme, l'âge supérieur à 50 ans et la dialyse inadéquate ne sont pas associés à ce trouble dans notre série
Shape-dependence of near-field heat transfer between a spheroidal nanoparticle and a flat surface
We study the radiative heat transfer between a spheroidal metallic
nanoparticle and a planar metallic sample for near- and far-field distances. In
particular, we investigate the shape dependence of the heat transfer in the
near-field regime. In comparison with spherical particles, the heat transfer
typically varies by factors between 1/2 and 2 when the particle is deformed
such that its volume is kept constant. These estimates help to quantify the
deviation of the actual heat transfer recorded by a near-field scanning thermal
microscope from the value provided by a dipole model which assumes a perfectly
spherical sensor
Selective nanomanipulation using optical forces
We present a detailed theoretical study of the recent proposal for selective
nanomanipulation of nanometric particles above a substrate using near-field
optical forces [Chaumet {\it et al.} Phys. Rev. Lett. {\bf 88}, 123601 (2002)].
Evanescent light scattering at the apex of an apertureless near-field probe is
used to create an optical trap. The position of the trap is controlled on a
nanometric scale via the probe and small objects can be selectively trapped and
manipulated. We discuss the influence of the geometry of the particles and the
probe on the efficiency of the trap. We also consider the influence of multiple
scattering among the particles on the substrate and its effect on the
robustness of the trap.Comment: 12 pages, 17 figure
Geostationary Emission Explorer for Europe (G3E): mission concept and initial performance assessment
The Geostationary Emission Explorer for Europe (G3E) is a concept for a geostationary satellite sounder that aims to constrain the sources and sinks of greenhouse gases carbon dioxide (CO2) and methane (CH4) for continental-scale regions. Its primary focus is on central Europe. G3E carries a spectrometer system that collects sunlight backscattered from the Earth\u27s surface and atmosphere in the near-infrared (NIR) and shortwave-infrared (SWIR) spectral range. Solar absorption spectra allow for spatiotemporally dense observations of the column-average concentrations of carbon dioxide (XCO2), methane (XCH4), and carbon monoxide (XCO). The mission concept in particular facilitates sampling of the diurnal variation with several measurements per day during summer.
Here, we present the mission concept and carry out an initial performance assessment of the retrieval capabilities. The radiometric performance of the 4 grating spectrometers is tuned to reconcile small ground-pixel sizes (~2 km × 3 km at 50° latitude) with short single-shot exposures (~2.9 s) that allow for sampling continental regions such as central Europe within 2 h while providing a sufficient signal-to-noise ratio. The noise errors to be expected for XCO2, XCH4, and XCO are assessed through retrieval simulations for a European trial ensemble. Generally, single-shot precision for the targeted XCO2 and XCH4 is better than 0.5 % with some exception for scenes with low infrared surface albedo observed under low sun conditions in winter. For XCO, precision is generally better than 10 %. Performance for aerosol and cirrus loaded atmospheres is assessed by mimicking G3E\u27s slant view on Europe for an ensemble of atmospheric scattering properties used previously for evaluating nadir-viewing low-Earth-orbit (LEO) satellites. While retrieval concepts developed for LEO configurations generally succeed in mitigating aerosol- and cirrus-induced retrieval errors for G3E\u27s setup, residual errors are somewhat greater in geostationary orbit (GEO) than in LEO. G3E\u27s deployment in the vicinity of the Meteosat Third Generation (MTG) satellites has the potential to make synergistic use of MTG\u27s sounding capabilities e.g. with respect to characterization of aerosol and cloud properties or with respect to enhancing carbon monoxide retrievals by combining G3E\u27s solar and MTG\u27s thermal infrared spectra
Geostationary Emission Explorer for Europe (G3E): mission concept and initial performance assessment
The Geostationary Emission Explorer for Europe (G3E) is a concept for a geostationary satellite sounder that targets at constraining the sources and sinks of the greenhouse gases carbon dioxide (CO2) and methane (CH4) for continental-scale regions. Thereby, its primary focus is on Central Europe. G3E carries a spectrometer system that collects sunlight backscattered from the Earth\u27s surface and atmosphere in the near-infrared (NIR) and shortwave-infrared (SWIR) spectral range. Solar absorption spectra allow for spatiotemporally dense observations of the column-average concentrations of carbon dioxide (XCO2), methane (XCH4), and carbon monoxide (XCO) including sampling of the diurnal variation with several measurements per day during summer. Here, we present the mission concept and carry out an initial performance assessment of the retrieval capabilities. The radiometric performance of the 4 grating spectrometers is tuned to reconcile small ground-pixel sizes (~ 2 km × 3 km at 50° latitude) with short single-shot exposures (∼ 2.9 s) that allow for sampling continental regions such as Central Europe within 2 h while providing sufficient signal-to-noise. The noise errors to be expected for XCO2, XCH4, and XCO are assessed through retrieval simulations for a European trial ensemble. Generally, single-shot precision for the targeted XCO2 and XCH4 is better than 0.5 % with some exception for scenes with low infrared surface albedo observed under low sun conditions in winter. For XCO, precision is generally better than 10 %. Performance for aerosol and cirrus loaded atmospheres is assessed by mimicking G3E\u27s slant view on Europe for an ensemble of atmospheric scattering properties used previously for evaluating nadir-viewing low-Earth-orbit (LEO) satellites. While retrieval concepts developed for LEO configurations generally succeed in mitigating aerosol and cirrus induced retrieval errors for G3E\u27s setup, residual errors are somewhat greater in geostationary orbit (GEO) than in LEO. G3E\u27s deployment in the vicinity of the Meteosat Third Generation (MTG) satellites suggests making synergistic use of MTG\u27s sounding capabilities e.g. with respect to characterization of aerosol and cloud properties or with respect to enhancing carbon monoxide retrievals by combining G3E\u27s solar and MTG\u27s thermal infrared spectra
Mechanisms explaining transitions between tonic and phasic firing in neuronal populations as predicted by a low dimensional firing rate model
Several firing patterns experimentally observed in neural populations have
been successfully correlated to animal behavior. Population bursting, hereby
regarded as a period of high firing rate followed by a period of quiescence, is
typically observed in groups of neurons during behavior. Biophysical
membrane-potential models of single cell bursting involve at least three
equations. Extending such models to study the collective behavior of neural
populations involves thousands of equations and can be very expensive
computationally. For this reason, low dimensional population models that
capture biophysical aspects of networks are needed.
\noindent The present paper uses a firing-rate model to study mechanisms that
trigger and stop transitions between tonic and phasic population firing. These
mechanisms are captured through a two-dimensional system, which can potentially
be extended to include interactions between different areas of the nervous
system with a small number of equations. The typical behavior of midbrain
dopaminergic neurons in the rodent is used as an example to illustrate and
interpret our results.
\noindent The model presented here can be used as a building block to study
interactions between networks of neurons. This theoretical approach may help
contextualize and understand the factors involved in regulating burst firing in
populations and how it may modulate distinct aspects of behavior.Comment: 25 pages (including references and appendices); 12 figures uploaded
as separate file
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