Une note sur le cylindre des langages déterministes

La famille des langages déterministes constitue un cylindre non principal. Nous redémontrons ce résultat de S.A. Greibach en décrivant cette famille comme l'union d'une infinité de cylindres emboîtés qui constituent une hiérarchie stricte, chacun d'entre eux étant ici un cylindre principal.     

Cytokines in vitreous humor: interleukin-6 is elevated in proliferative vitreoretinopathy

PURPOSE: To measure the levels of interleukins (IL) 1 beta, 6, and 8, and tumor necrosis factor-alpha (TNF alpha) in the vitreous of patients with proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), vitreous hemorrhage, and macular pucker. METHODS: Vitreous samples were collected, undiluted, from patients with PVR, PDR of varying severity, and miscellaneous lesions (vitreous hemorrhage from trauma, macular degeneration, vein occlusion, and non-PVR patients with giant tear, retinal detachment, and macular pucker). Immunoreactive levels of the cytokines, IL-1 beta, IL-6, IL-8, and TNF alpha were determined by enzyme-linked immunoadsorbent assays, and samples were analyzed for protein and hyaluronic acid content using standard assays. RESULTS: The levels of TNF alpha were below detection limits of the assay (< 3 pg/ml). In 45 of the 47 samples tested, IL-1 beta levels also were below detection limits of the assay (< 3 pg/ml). IL-6 levels ranged from < 30 to 5487 pg/ml, with the highest values observed in the PVR patients. IL-8 levels ranged from < 20 to 1900 pg/ml, and were consistently high in the miscellaneous group. Some of the PVR patients with C2 and C3 level severity also exhibited IL-8 levels exceeding 100 pg/ml. In a second study, IL-6 content of vitreous from miscellaneous and PVR patients was compared. In this study, significantly elevated levels of IL-6 were observed in the PVR patients (91.5 +/- 18 pg/ml) compared to the miscellaneous group (10.3 +/- 3.7 pg/ml) CONCLUSIONS: Elevated levels of IL-6 in the vitreous occur in PVR, implicating a role for this cytokine in the pathogenesis of this ocular disorder.     

Le diagnostic des circuits intégrés par faisceau d’électrons

The purpose of this synthetic article is to show how the electron beam testing technique of prototype integrated circuits after a first run has now reached maturity. Firstly the physics of measurement has been the subject of many improvements which means that results, both more reliable and more precise (in voltage and in time) can be obtained more quickly. Moreover this improved performance has led to the development of fully comprehensive diagnosis stations so ergonomic that the user forgets his scanning electron microscope, stations which become the final link in the chain of computer aided design.     

Kinetics of phase separation in polyurethane/polystyrene semi-1 interpenetrating polymer networks. 2. Microscopy observations and theoretical approach

The phase separation process of in-situ polyurethane/polystyrene semi-1 interpenetrating polymer networks has been followed by optical microscopy completed by image analysis. The final morphology has been examined by scanning electron microscopy, and its relation to the phase separation process has been established. When phase separation occurs before gelation of the medium, polystyrene is dispersed both as large and small noduli in the polyurethane network; a polyurethane-rich interphase separates the noduli from the matrix. These observations explain the previous results on the turbidity of such systems measured by light transmission. In the opposite cases, no visible phase separation is observed on the micrographs. The thermodynamics of the phase separation process has also been examined.     

Evolution structurale par substitution cationique dans les perovskites hexagonales fluorees: II - Les systèmes Cs1−xRbxMF3 (M = Mg,Co, Ni,Zn)

The substitution of rubidium for cesium in CsMF₃ phases has the same influence as pressure. While no phase transformation is observed if M is magnesium or zinc, the sequences 2H → 9R → 6H and 9R → 6H → 3C are respectively observed in the case of nickel and cobalt with increasing rubidium concentration. The 9R-Cs_0.70 Rb_0.30 NiF₃ phase is antiferromagnetic and the 6H-Cs_0.50 Rb_0.50 CoF₃ compound is a ferrimagnet (T_C = 62 K).     

An A Contrario Decision Method for Shape Element Recognition

Shape recognition is the field of computer vision which addresses the problem of finding out whether a query shape lies or not in a shape database, up to a certain invariance. Most shape recognition methods simply sort shapes from the database along some (dis-)similarity measure to the query shape. Their main weakness is the decision stage, which should aim at giving a clear-cut answer to the question: “do these two shapes look alike?” In this article, the proposed solution consists in bounding the number of false correspondences of the query shape among the database shapes, ensuring that the obtained matches are not likely to occur “by chance”. As an application, one can decide with a parameterless method whether any two digital images share some shapes or not.     

Facteur de couplage phase-amplitude des diodes lasers avec absorbant saturable

The phase-amplitude coupling factor (α-factor) is one of the fundamental parameters of semiconductor lasers. We show that this factor can be evaluated by time-resolved spectroscopic measurements in pulsed regime. Experiments are carried out with injectionseeded single-mode GaAs lasers whose active stripe includes regions of saturable absorption made by ion implantation. We show that the measured pulse downchirp is proportional to pulse energy. The downchirp amplitude is found to approach four laser cavity intermode spacings at the highest energies. Correspondingly, the ±-values can be five times higher than those reported to date in litterature. High a-values are confirmed in pulse compression experiments. Several mechanisms are proposed to interprete these new results.     

Opérations de cylindre et applications séquentielles gauches inverses

Résumé Dans cet article, on étudie les rapports entre la principauté d'une famille de langages en tant que cylindre et en tant que famille fermée par application séquentielle gauche (gsm) inverse. Pour cela on considère les familles de langages closes pour les opérations de cylindre et les gsm inverses. On montre qu'une telle famille est principale en tant que cylindre seulement si elle est principale vis à vis des gsm inverses, mais que l'inverse n'est pas vrai. Cependant, si l'on se restreint aux familles de langages vérifiant une propriété de clôture que l'on explicite, on obtient cette réciproque.

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In this paper, the relations between the principality of a family of languages as a cylinder and its principality as family closed under inverse gsm mappings are studied. For that purpose, the families of languages closed under the operations of cylinder and under inverse gsm mappings are considered. It is shown that such a family is a principal cylinder only if it is principal through the operation of inverse gsm mapping, but that the converse is not true. However, the converse is true for the families satisfying a closure property given here.

     

Experiences in the use of suprapubic bladder drainage after gynecologic surgery

Suprapubic catheterisation using a lately available puncture set for single use has been performed by us after major gynecologic surgery. Very favorable results of 48 suprapubic catheterisations performed under systematic control are reported.     

Least-squares support vector machines modelization for time-resolved spectroscopy

By use of time-resolved spectroscopy it is possible to separate light scattering effects from chemical absorption effects in samples. In the study of propagation of short light pulses in turbid samples the reduced scattering coefficient and the absorption coefficient are usually obtained by fitting diffusion or Monte Carlo models to the measured data by use of numerical optimization techniques. In this study we propose a prediction model obtained with a semiparametric modeling technique: the least-squares support vector machines. The main advantage of this technique is that it uses theoretical time dispersion curves during the calibration step. Predictions can then be performed by use of data measured on different kinds of sample, such as apples.