15 research outputs found
A multi-site campaign to measure solar-like oscillations in Procyon. II. Mode frequencies
We have analyzed data from a multi-site campaign to observe oscillations in
the F5 star Procyon. The data consist of high-precision velocities that we
obtained over more than three weeks with eleven telescopes. A new method for
adjusting the data weights allows us to suppress the sidelobes in the power
spectrum. Stacking the power spectrum in a so-called echelle diagram reveals
two clear ridges that we identify with even and odd values of the angular
degree (l=0 and 2, and l=1 and 3, respectively). We interpret a strong, narrow
peak at 446 muHz that lies close to the l=1 ridge as a mode with mixed
character. We show that the frequencies of the ridge centroids and their
separations are useful diagnostics for asteroseismology. In particular,
variations in the large separation appear to indicate a glitch in the
sound-speed profile at an acoustic depth of about 1000 s. We list frequencies
for 55 modes extracted from the data spanning 20 radial orders, a range
comparable to the best solar data, which will provide valuable constraints for
theoretical models. A preliminary comparison with published models shows that
the offset between observed and calculated frequencies for the radial modes is
very different for Procyon than for the Sun and other cool stars. We find the
mean lifetime of the modes in Procyon to be 1.29 +0.55/-0.49 days, which is
significantly shorter than the 2-4 days seen in the Sun.Comment: accepted for publication in Ap
A História da Alimentação: balizas historiogråficas
Os M. pretenderam traçar um quadro da HistĂłria da Alimentação, nĂŁo como um novo ramo epistemolĂłgico da disciplina, mas como um campo em desenvolvimento de prĂĄticas e atividades especializadas, incluindo pesquisa, formação, publicaçÔes, associaçÔes, encontros acadĂȘmicos, etc. Um breve relato das condiçÔes em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biolĂłgica, a econĂŽmica, a social, a cultural e a filosĂłfica!, assim como da identificação das contribuiçÔes mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histĂłrica, foi ela organizada segundo critĂ©rios morfolĂłgicos. A seguir, alguns tĂłpicos importantes mereceram tratamento Ă parte: a fome, o alimento e o domĂnio religioso, as descobertas europĂ©ias e a difusĂŁo mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rĂĄpido balanço crĂtico da historiografia brasileira sobre o tema
Thermal Analysis for Velocity, Kinetics, and Enthalpy Reaction Measurements in Microfluidic Devices
International audienc
Numerical Inversion of Laplace Transform for Time Resolved Thermal Characterization Experiment
Thermal quadrupole method with internal heat sources
A new method based on the thermal quadrupoles technique for heat transfer modelling in multilayered slabs with heat sources is proposed. Classical thermal quadrupoles use hyperbolic functions and numerical problems occur according to the argument value that depends on thermophysical and geometrical properties as well as characteristics times. We propose a new formulation based on exponential function with negative argument. Using this formulation in the classical equivalent impedance network allows to compute efficiently the thermal behaviour of multilayered slabs with internal heat sources whatever the time and the thermophysical properties. This approach is applied in order to simulate heat transfer in three different multilayered materials with heat sources. These simulations show the capability of such a methodology to simulate time and space multiscale heat diffusion problems
Enthalpy, kinetics and mixing characterization in droplet-flow millifluidic device by infrared thermography
International audienc
Permeability of fibrous carbon materials
The air permeability of a number of commercial fibrous carbon materials: soft non-woven felts, rigidised felts and rigid boards, based on either PAN- or Rayon-derived fibres presenting various diameters, graphitised or not, and consolidated by different methods, was measured and investigated. Consistent behaviours were found within families of closely related materials, but the diversity of porous structures prevented any model, including the very popular TomadakisâSotirchos equation, to fit all results. The Archieâs coefficient and the tortuosity factor for viscous flow were thus calculated. Not only all data were perfectly aligned on one single master curve, but the analysis was extended to many other fibrous materials and the same master curve was found to be relevant. The Archieâs coefficient thus appears to be an intrinsic property, purely defined by the material geometry, as it does not depend on the 1D, 2D or 3D type of flow. A fitting equation was proposed, encompassing all fibrous materials in very broad ranges of porosities and porous structures
Pharmacokinetic/pharmacodynamic modelling of NSAIDs in a model of reversible inflammation in the cat
1. Data on the relationships between plasma concentration and analgesic and anti-inflammatory effects of NSAIDs are limited because most inflammation models do not permit pharmacokinetic/pharmacodynamic (PK/PD) modelling to be readily performed. 2. In this study, a kaolin-induced inflammation model in the cat was evaluated for pre-clinical characterization of the pharmacodynamic profiles of NSAIDs (determination of efficacy, potency, sensitivity (that is the slope of the concentrationâeffect relationship) and duration of drug response), using meloxicam as a probe article. 3. Indirect response PK/PD models described the time course and magnitude of responses produced by 0.3âmgâkg(â1) meloxicam administered subcutaneously. For endpoints for which spontaneous recovery from inflammation was superimposed on drug response, a PK/PD model with a time-dependent K(in) was used to allow for the spontaneous changes of the inflammation with time. 4. The selected endpoints were suitable for studying simultaneously the analgesic, anti-inflammatory and antipyretic effects of meloxicam, allowing comparison of relative potencies for these effects. Mean±s.d. IC(50) or EC(50) values (ngâml(â1)) were 777±124 (body temperature), 841±187 (locomotion variable), 883±215 (pain score), 911±189 (lameness score) and 1298±449 (skin temperature difference). Corresponding mean times±s.d. of peak responses (h) were 5.6±1.3, 8.6±3.8, 5.2±5.0, 5.6±3.7 and 4.3±2.4, respectively. 5. As the pharmacokinetic profiles of meloxicam in cats and humans are similar, simulations of several dosage regimens in the cat provided a pre-clinical basis, illustrating the value of the cat model for predicting a clinical dose regimen for evaluation in man. The predicted loading doses (mgâkg(â1)) of meloxicam in the cat producing 70% of the maximum attainable responses were 0.29 (body temperature), 0.32 (lameness score), 0.33 (overall locomotion variable), 0.36 (pain score) and 0.50 (skin temperature difference). The values are similar to or somewhat greater than the clinically recommended doses both in cats (0.3âmgâkg(â1)) and humans (7.5â15âmg, that is, between 0.1 and 0.3âmgâkg(â1)). 6. These findings indicate the potential value of the cat as a laboratory model, and of a PK/PD modelling approach in assisting NSAID development programs in animals and humans
Permanent or transient chronic ischemic stroke in the non-human primate: behavioral, neuroimaging, histological, and immunohistochemical investigations
Using multimodal magnetic resonance imaging (MRI), behavioral, and immunohistochemical analyses, we examined pathological changes at the acute, sub-acute, and chronic stages, induced by permanent or temporary ischemia in the common marmoset. Animals underwent either permanent (pMCAO) or 3-h transient (tMCAO) occlusion of the middle cerebral artery (MCAO) by the intraluminal thread approach. MRI scans were performed at 1âh, 8, and 45 days after MCAO. Sensorimotor deficits were assessed weekly up to 45 days after MCAO. Immunohistological studies were performed to examine neuronal loss, astrogliosis, and neurogenesis. Remote lesions were analyzed using retrograde neuronal tracers. At day 8 (D8), the lesion defined on diffusion tensor imaging (DTI)âMRI and T2-MRI was significantly larger in pMCAO as compared with that in the tMCAO group. At D45, the former still displayed abnormal signals in T2-MRI. Post-mortem analyses revealed widespread neuronal loss and associated astrogliosis to a greater extent in the pMCAO group. Neurogenesis was increased in both groups in the vicinity of the lesion. Disconnections between the caudate and the temporal cortex, and between the parietal cortex and the thalamus, were observed. Sensorimotor impairments were more severe and long-lasting in pMCAO relative to tMCAO. The profile of brain damage and functional deficits seen in the marmoset suggests that this model could be suitable to test therapies against stroke
Patterns biogéographiques de la diversité bactérienne des sols à l'échelle du territoire national
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