495 research outputs found

    ConSUS: A light-weight program conditioner

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    Program conditioning consists of identifying and removing a set of statements which cannot be executed when a condition of interest holds at some point in a program. It has been applied to problems in maintenance, testing, re-use and re-engineering. All current approaches to program conditioning rely upon both symbolic execution and reasoning about symbolic predicates. The reasoning can be performed by a ‘heavy duty’ theorem prover but this may impose unrealistic performance constraints. This paper reports on a lightweight approach to theorem proving using the FermaT Simplify decision procedure. This is used as a component to ConSUS, a program conditioning system for the Wide Spectrum Language WSL. The paper describes the symbolic execution algorithm used by ConSUS, which prunes as it conditions. The paper also provides empirical evidence that conditioning produces a significant reduction in program size and, although exponential in the worst case, the conditioning system has low degree polynomial behaviour in many cases, thereby making it scalable to unit level applications of program conditioning

    Etude ethnobotanique de quelques lavandes marocaines spontanées

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    Le genre Lavandula est l'un des plus importants genres de la famille des Lamiacées et est riche en plantes à usage multiple, alimentaire, fourrager, aromatique, cosmétique et médicinal. Au Maroc, la bibliographie fait allusion à plusieurs espèces de ce genre, communément appelées lavandes, à écologie et phytogéographie diversifiées et dont d’une part la distinction taxinomique n’est pas des plus faciles et d’autre part l’éventualité d’un usage différent selon les localités et ou les espèces n’est pas investie. Aussi, l’objectif du présent travail est de rechercher les lavandes dans différentes régions du Maroc ; puis, par le biais d’investigations ethnobotaniques auprès d’herboristes et de vendeurs de plantes aromatiques et médicinales (PAM), inventorier leurs principaux usages traditionnels. Ainsi, durant l’année 2014, des prospections floristiques à la recherche de lavandes sauvages ont permis de repérer et localiser Lavandula stoechas L et L. atlantica Braun-Blanq , L. pedunculata Mill, L. multifida L, L. dentata L, L. maroccana Murb respectivement au plateau central « Oulmès, et Aguelmous » et au moyen atlas central « Ait Amro Ouali », la plaine de Sais « Ain Jerri », et en haut atlas occidental « bassin versant d’Ourika ». Les enquêtes ethnobotaniques menées auprès d’herboristes et vendeurs dans chaque site de récolte, via un questionnaire préétabli ont permis de dresser la liste des noms vernaculaires utilisés pour chaque espèce et ont révélé que les lavandes ont essentiellement des vertus thérapeutiques, que les feuilles et les fleurs sont les parties les plus utilisées surtout sous forme de décoction pour le traitement d’affections broncho-pulmonaires, gastrointestinales et uro-génitales.Mots clés : Lavandula, plantes aromatique et médicinales, enquête ethnobotanique, Maroc

    Minéralisation Pb-Zn du type MVT de la région d’Ali ou Daoud (Haut Atlas Central, Maroc): caractérisations du gîte et relations avec les cortèges de minéraux argileux

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    Zn-Pb-Fe ores in the Ali ou Daoud deposit (Central High Atlas) are found as stratiform levels and as karst fillings in carbonate platforms facies of Bajocian age. Tectonic structures (e.g., synsedimentary faults) played a relevant role in the ore emplacement. The dolomitic ore-related host-rock levels are characterized by the presence of kaolinite enrichment in clay levels in amounts directly related to the proportion of the clay minerals. The latter is evidenced by correlation between kaolinite and sulphide contents, suggesting that the installation of kaolinite and mineralisations would result from the same hydrothermal fluid.[Français] Dans les séries sédimentaires carbonatées d’Ali ou Daoud (Haut Atlas Central), les minéralisations à Zn, Pb et Fe en amas stratiformes forment les faciès de remplissage des karsts d’une plateforme carbonatée bajocienne. Le contrôle structural joue un rôle capital dans la localisation du gîte en bordure de plateforme sur des failles synsédimentaires. Dans les niveaux dolomitiques encaissants des minéralisations, les assemblages argileux sont caractérisés par la présence de kaolinite dont la teneur varie parallèlement avec celle du minerai. Ceci suggère que la mise en place de la kaolinite et des minéralisations résulterait du même fluide hydrothermal. [Español] En las series sedimentarias carbonatadas de Ali ou Daoud (Alto Atlas Central), las mineralizaciones de Zn, Pb y Fe aparecen en niveles estratiformes como facies de reemplazamiento de los karsts de una plataforma carbonatada Bajociense. El control estructural desempeña un papel crucial en la localización del yacimiento a lo largo de la plataforma sobre fallas sinsedimentarias. En los niveles dolomíticos que incluyen las mineralizaciones, las asociaciones arcillosas se caracterizan por la presencia de caolinita, cuyo contenido varía paralelamente al de la mineralización. Esto sugiere que la creación de caolinita y de la mineralización resultarían del mismo fluido hidrotermal. (traducido por el Editor)

    Proton conductivity in Al-stevensite pillared clays

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    Fine stevensite mineral fraction (< 2 m) has been extracted from natural Moroccan ghassoulite clay. Thereafter, it has been pillared by Al13 polycations species. Physico-chemical characterization, performed using X-ray diffraction (XRD), thermal analysis (TG-TDA) and Scanning Electron Microscopy (SEM) equipped with X-ray Energy Dispersion (XED) analysis, has proved that stevensite pillaring has been successfully achieved. Electrical impedance measurements, carried out onto samples before and after pillaring operation, have shown an increase in proton conductivity for pillared with respect to pristine stevensite clay mineral.Fine stevensite mineral fraction (< 2 m) has been extracted from natural Moroccan ghassoulite clay. Thereafter, it has been pillared by Al13 polycations species. Physico-chemical characterization, performed using X-ray diffraction (XRD), thermal analysis (TG-TDA) and Scanning Electron Microscopy (SEM) equipped with X-ray Energy Dispersion (XED) analysis, has proved that stevensite pillaring has been successfully achieved. Electrical impedance measurements, carried out onto samples before and after pillaring operation, have shown an increase in proton conductivity for pillared with respect to pristine stevensite clay mineral

    Elucidating the crystal-chemistry of Jbel Rhassoul stevensite (Morocco) by advanced analytical techniques

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    The composition of Rhassoul clay is controversial regarding the nature of the puremineral clay fraction which is claimed to be stevensite rather than saponite. In this study, the raw and mineral fractions were characterized using various techniques including Fourier transform infrared spectroscopy and magic angle spinning nuclear magnetic resonance (MAS NMR). The isolated fine clay mineral fraction contained a larger amount of Al (>1 wt.%) than that reported for other stevensite occurrences. The 27Al MAS NMR technique confirmed that the mineral is stevensite in which the Al is equally split between the tetrahedral and octahedral coordination sites. The 29Si NMR spectrum showed a single unresolved resonance indicating little or no short-range ordering of silicon. The chemical composition of the stevensite from Jbel Rhassoul was determined to be ((Na0.25K0.20 (Mg5.04Al0.37Fe0.20&0.21)5.61(Si7.76Al0.24)8O20(OH)4). This formula differs from previous compositions described from this locality and shows it to be an Al-bearing lacustrine clay mineral

    Profil actuel des bactériémies au Service des Maladies Infectieuses : A propos de 216 cas

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    Résumé Les caractères épidémiologiques, cliniques et bactériologiques des bactériémies varient en fonction du service où l'étude est réalisée. Le but de ce travail est d’étudier les caractères épidémiologiques des bactériémies observées dans un service de Maladies Infectieuses. Nous avons réalisé une étude rétrospective qui a porté sur 216 épisodes bactériémiques observés chez 216 patients hospitalisés dans le service entre janvier 2013 et juin 2014. L'âge moyen de nos malades était de 40 ans, une tare préexistante était présente chez 108patients (50%), dominée par le diabète (12%), HTA (7%), néphropathie (5%), l’infection a VIH a été retrouvé chez 18% des cas. Une porte d'entrée était identifiée chez 140 malades (65%). Les portes d'entrée urinaire et cutanée étaient les plus fréquentes respectivement dans 48 % et 30 % des épisodes bactériémiques. L'origine nosocomiale de la bactériémie était retenue dans 8% des cas. Les germes les plus fréquemment isolés étaient les bacilles à Gram négatif (54%) au premier rang desquels Escherichia coli suivi de Klebsiella pneumoniae. Les cocci à Gram positif étaient à l'origine de 46 % des bactériémies avec prédominance de Staphylococcus aureus. La mortalité globale était de 15% .La mortalité était de 33% pour la bactériémie à Klebsiella pneumoniae

    Syntax-directed amorphous slicing

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    An amorphous slice of a program is constructed with respsct to a set of variables. The amorphous slice is an executable program which preserves the behaviour of the original on the variables of interest. Unlike syntax-preserving slices, amorphous slices need not preserve a projection of the syntax of a program. This makes the task of amorphous slice construction harder, but it also often makes the result thinner and thereby preferable in applications where syntax preservation is unimportant. This paper describes an approach to the construction of amorphous slices which is based on the Abstract Syntax Tree of the program to be sliced, and does not require the construction of control flow graphs nor of program dependence graphs. The approach has some strengths and weaknesses which the paper discusses. The amorphous slicer, is part of the GUSTT slicing system, which includes syntax preserving static and conditioned slicers, a side effect removal transformation phase, slicing criterion guidance and for which much of the correctness proofs for transformation steps are mechanically verified. The system handles a subset of WSL, into which more general WSL constructs can be transformed. The paper focuses upon the way in which the GUSTT System uses dependence reduction transformation tactics. Such dependence reduction is at the heart of all approaches to amorphous slicing. The algorithms used are described and their performance is assessed with a simple empirical study of best and worst case execution times for an implementation built on top of the FermaT transformation system for maintenance and re-engineering

    Temporal Evolution of the Solar Wind Bulk Velocity atSolar Minimum by Correlating the STEREO A andBPLASTIC Measurements

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    The two STEREO spacecraft with nearly identical instrumentation were launched near solar activity minimum and they separate by about 45° per year, providing a unique tool to study the temporal evolution of the solar wind. We analyze the solar wind bulk velocity measured by the two PLASTIC plasma instruments onboard the two STEREO spacecraft. During the first half year of our measurements (March - August 2007) we find the typical alternating slow and fast solar wind stream pattern expected at solar minimum. To evaluate the temporal evolution of the solar wind bulk velocity we exclude the spatial variations and calculate the correlation between the solar wind bulk velocity measured by the two spacecraft. We account for the different spacecraft positions in radial distance and longitude by calculating the corresponding time lag. After adjusting for this time lag we compare the solar wind bulk velocity measurements at the two spacecraft and calculate the correlation between the two time-shifted datasets. We show how this correlation decreases as the time difference between two corresponding measurements increases. As a result, the characteristic temporal changes in the solar wind bulk velocity can be inferred. The obtained correlation is 0.95 for a time lag of 0.5 days and 0.85 for 2 day

    Self-similar chain conformations in polymer gels

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    We use molecular dynamics simulations to study the swelling of randomly end-cross-linked polymer networks in good solvent conditions. We find that the equilibrium degree of swelling saturates at Q_eq = N_e**(3/5) for mean strand lengths N_s exceeding the melt entanglement length N_e. The internal structure of the network strands in the swollen state is characterized by a new exponent nu=0.72. Our findings are in contradiction to de Gennes' c*-theorem, which predicts Q_eq proportional N_s**(4/5) and nu=0.588. We present a simple Flory argument for a self-similar structure of mutually interpenetrating network strands, which yields nu=7/10 and otherwise recovers the classical Flory-Rehner theory. In particular, Q_eq = N_e**(3/5), if N_e is used as effective strand length.Comment: 4 pages, RevTex, 3 Figure
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