997 resultados para STARS: FUNDAMENTAL PARAMETERS


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Despite the increase of animal and plant introductions worldwide and the strong augmentation of the reptile trade, few invasive snake populations have been studied. Dice snakes (Natrix tessellata) were introduced to the shores of Lake Geneva (Switzerland) in the early 1920s, and are now well established. This region of introduction was previously inhabited by Viperine snakes (N. maura). Ever since these two species have been under monitoring (which began in 1996) the Viperine snake population has shown drastic decline. We examine here the possibility of trophic competition by analysing diet composition, prey size and trophic niche overlap. Spatial distribution is also assessed in order to address the question of spatial competitive exclusion. We found very similar diets, and thus a high trophic niche overlap, indicating no partitioning of the trophic resource. No arguments in favour of spatial competitive exclusion were found. Our study suggests that trophic competition may occur between the two natricines and that it may give an explanation for the drastic decline of the Viperine snake in this area. Other pathways potentially playing a role in the exclusion of the Viperine snake are discussed.

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Geophysical techniques can help to bridge the inherent gap with regard to spatial resolution and the range of coverage that plagues classical hydrological methods. This has lead to the emergence of the new and rapidly growing field of hydrogeophysics. Given the differing sensitivities of various geophysical techniques to hydrologically relevant parameters and their inherent trade-off between resolution and range the fundamental usefulness of multi-method hydrogeophysical surveys for reducing uncertainties in data analysis and interpretation is widely accepted. A major challenge arising from such endeavors is the quantitative integration of the resulting vast and diverse database in order to obtain a unified model of the probed subsurface region that is internally consistent with all available data. To address this problem, we have developed a strategy towards hydrogeophysical data integration based on Monte-Carlo-type conditional stochastic simulation that we consider to be particularly suitable for local-scale studies characterized by high-resolution and high-quality datasets. Monte-Carlo-based optimization techniques are flexible and versatile, allow for accounting for a wide variety of data and constraints of differing resolution and hardness and thus have the potential of providing, in a geostatistical sense, highly detailed and realistic models of the pertinent target parameter distributions. Compared to more conventional approaches of this kind, our approach provides significant advancements in the way that the larger-scale deterministic information resolved by the hydrogeophysical data can be accounted for, which represents an inherently problematic, and as of yet unresolved, aspect of Monte-Carlo-type conditional simulation techniques. We present the results of applying our algorithm to the integration of porosity log and tomographic crosshole georadar data to generate stochastic realizations of the local-scale porosity structure. Our procedure is first tested on pertinent synthetic data and then applied to corresponding field data collected at the Boise Hydrogeophysical Research Site near Boise, Idaho, USA.

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The development of new drug delivery systems to target the anterior segment of the eye may offer many advantages: to increase the biodisponibility of the drug, to allow the penetration of drug that cannot be formulated as solutions, to obtain constant and sustained drug release, to achieve higher local concentrations without systemic effects, to target more specifically one tissue or cell type, to reduce the frequency of instillation and therefore increase the observance and comfort of the patient while reducing side effects of frequent instillation. Several approaches are developed, aiming to increase the corneal contact time by modified formulation or reservoir systems, or by increasing the tissue permeability using iontophoresis. To date, no ocular drug delivery system is ideal for all purposes. To maximize treatment efficacy, careful evaluation of the specific pathological condition, the targeted Intraocular tissue and the location of the most severe pathology must be made before selecting the method of delivery most suitable for each individual patient.

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RESUME : Les dermatophytes sont les agents infectieux les plus fréquents responsables de la plupart des mycoses superficielles chez les humains et chez les animaux. Ces infections, dermatophytoses, également appelées tineas ou teignes, sont fréquentes et causent des problèmes de santé publique au niveau mondial. La capacité d'envahir et de progresser au sein des structures kératinisées est probablement liée à la sécrétion de différentes enzymes kératinolytiques, qui sont considérées comme la principale caractéristique liée à la pathogénicité de ces champignons. L'objectif de ma thèse a été premièrement de progresser dans l'identification et la caractérisation des nouvelles protéines sécrétées, afin de mieux comprendre a) la capacité globale des dermatophytes à envahir les structures kératinisées, et b) les différences dans la virulence et la spécificité d'hôte que présentent les espèces étudiées .Pour progresser dans l'identification et la caractérisation de ces nouvelles protéines, les secretomes de six espèces de dermatophytes (Trichophyton rubrum, Trichophyton violaceum, Trichophyton soudanense, Trichophyton equinum, Arthroderma vanbreuseghemii et Trichophyton tonsurans) ont été étudiés. Bien qu'il y ait un niveau globalement élevé de similitude entre les protéases sécrétées, les différentes espèces de dermatophytes sécrètent des profiles protéiques distincts lorsqu'elles sont cultivées dans les mêmes conditions de culture, et donc une signature spécifique a pu être associé à chaque espèce. Ces profiles ont été un outil avantageux pour identifier et cartographier les protéines orthologues aux six espèces et ont aussi permit la discrimination d'espèces très proches comme T. tonsurans et T. equinum qui ne peuvent pas être différenciées par l'ADN ribosomal. Ce travail également présente ce que l'on croit être la première identification global des protéines sécrétées par les dermatophytes dans des conditions de culture que incitent l'activité protéolytique extracellulaire. Ce catalogue de protéines, comprenant des endo- and exo- proteases, autres hydrolases, oxydoreductases et des protéines avec fonction inconnue, représente probablement le spectre d'enzymes qui permettent la dégradation des tissus kératinisés en composés qui peuvent être assimilés par le champignon. Les résultats suggèrent qu'un changement écologique pourrait être associé à une expression différentielle des gènes codant les protéines sécrétées, en particulier, les protéases, plutôt qu'à des divergences génétiques au niveau des gènes codant les protéines orthologues. Une sécrétion différentielle des protéines par les dermatophytes pourrait également être responsable de la variabilité inflammatoire qui causent ces agents infectieux chez les différents hôtes. Par conséquent, les protéines identifiées ici sont également importantes pour faire la lumière sur la réponse immunitaire de l'hôte au cours du processus infectieux. SUMMARY : Dermatophytes are the most common infectious agents responsible for superficial mycosis in humans and animals. Dermatophytoses, also called tineas or ringworm, are frequent and cause public health problems worldwide. The secretion of different keratinolytic enzymes is believed to be a key pathogenicity-related characteristic of these fungi. The aim of this work was first to progress in the identification and characterization of novel secreted proteins, in order to better understand a) the overall capability of dermatophytes to invade keratinised structures, and b) differences in virulence and host-specificity of the investigated species. To progress in the identification and characterization of novel proteins, the secretomes from Trichophyton rubrum, Trichophyton violaceum, Trichophyton soudanense, Trichophyton equinum, Arthroderma vanbreuseghemii and Trichophyton tonsurans were studied. Although there is a high global level of similarity among the secreted proteases, different dermatophyte species produce distinct patterns of proteins when grown in the same culture medium, and so a specific signature could be associated to each species. These patterns were useful to identify and map orthologous proteins among the six species, as well as to discriminate the closely related species T. tonsurans and T. equinum, which cannot be differentiated by ribosomal DNA. This work also presents the first in-depth identification of the major proteins secreted by dermatophytes growing under conditions promoting extracellular proteolytic activity. This catalogue of proteins, which include several endo- and exo- proteases, other hydrolases, oxydoreductases, and proteins of unknown function, probably represents the spectrum of enzymes that allow the degradation of keratinized tissues into compounds which can be assimilated by the fungus. The results suggest that ecological switching could be related to a differential expression of genes encoding secreted proteins, particularly, proteases, rather than genetic divergences of the genes encoding orthologous proteins. Differential secretion of proteins by Dermatophyte species could also be responsible for the variable inflammation caused by the infectious agent within the host. Therefore, the proteins here identified are also important to shed light into the immune response of the host during the infection process.

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Introduction: Ankle arthrodesis (AD) and total ankle replacement (TAR) are typical treatments for ankle osteoarthritis (AO). Despite clinical interest, there is a lack of their outcome evaluation using objective criteria. Gait analysis and plantar pressure assessment are appropriate to detect pathologies in orthopaedics but they are mostly used in lab with few gait cycles. In this study, we propose an ambulatory device based on inertial and plantar pressure sensors to compare the gait during long-distance trials between healthy subjects (H) and patients with AO or treated by AD and TAR. Methods: Our study included four groups: 11 patients with AO, 9 treated by TAR, 7 treated by AD and 6 control subjects. An ambulatory system (Physilog®, CH) was used for gait analysis; plantar pressure measurements were done using a portable insole (Pedar®-X, DE). The subjects were asked to walk 50 meters in two trials. Mean value and coefficient of variation of spatio-temporal gait parameters were calculated for each trial. Pressure distribution was analyzed in ten subregions of foot. All parameters were compared among the four groups using multi-level model-based statistical analysis. Results: Significant difference (p <0.05) with control was noticed for AO patients in maximum force in medial hindfoot and forefoot and in central forefoot. These differences were no longer significant in TAR and AD groups. Cadence and speed of all pathologic groups showed significant difference with control. Both treatments showed a significant improvement in double support and stance. TAR decreased variability in speed, stride length and knee ROM. Conclusions: In spite of a small sample size, this study showed that ankle function after AO treatments can be evaluated objectively based on plantar pressure and spatio-temporal gait parameters measured during unconstrained walking outside the lab. The combination of these two ambulatory techniques provides a promising way to evaluate foot function in clinics.

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A raíz de la evolución del precio de la energía y de las medidas adoptadas a nivel mundial para el llamado “desarrollo sostenible”, la legislación europea ha liderado las correcciones a efectuar en los procesos protagonistas del consumo de recursos y de contaminación del medio ambiente. En la última década el proceso viene acelerándose para cumplir con los objetivos marcados, amparándose en unas ya consolidadas estadísticas sobre las repercusiones prácticas de cada una de las iniciativas proyectadas. Una de las tecnologías a emplear es la cogeneración, es decir, la producción simultánea de calor y electricidad. A diferencia de otras soluciones más ambiciosas, y por tanto con mayor incertidumbre en su aplicación práctica, la cogeneración es una respuesta ya madura y viable, directamente aplicable a industrias y con un claro apoyo institucional. El objetivo principal de este trabajo es demostrar mediante un estudio técnico – económico, la viabilidad de la solución planteada en este tipo de edificios, mediante la aportación de datos reales y contrastados. Así como establecer los parámetros e indicadores de medición que permitan elegir dicha tecnología como la solución óptima para el ahorro y eficiencia económica en su sector de aplicación. Entre las conclusiones más destacadas de este proyecto están los beneficios que aporta tanto al usuario del sistema como al conjunto de la sociedad, siendo este último aspecto fundamental en su financiación y subvención. Por otra parte, son instalaciones desconocidas en ciertos edificios por lo que este trabajo debe contribuir a su desarrollo y adopción por parte de las empresas de servicios energéticos.

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Defining the limits of an urban agglomeration is essential both for fundamental and applied studies in quantitative and theoretical geography. A simple and consistent way for defining such urban clusters is important for performing different statistical analysis and comparisons. Traditionally, agglomerations are defined using a rather qualitative approach based on various statistical measures. This definition varies generally from one country to another, and the data taken into account are different. In this paper, we explore the use of the City Clustering Algorithm (CCA) for the agglomeration definition in Switzerland. This algorithm provides a systemic and easy way to define an urban area based only on population data. The CCA allows the specification of the spatial resolution for defining the urban clusters. The results from different resolutions are compared and analysed, and the effect of filtering the data investigated. Different scales and parameters allow highlighting different phenomena. The study of Zipf's law using the visual rank-size rule shows that it is valid only for some specific urban clusters, inside a narrow range of the spatial resolution of the CCA. The scale where emergence of one main cluster occurs can also be found in the analysis using Zipf's law. The study of the urban clusters at different scales using the lacunarity measure - a complementary measure to the fractal dimension - allows to highlight the change of scale at a given range.

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The relation between the low-energy constants appearing in the effective field theory description of the Lambda N -> NN transition potential and the parameters of the one-meson-exchange model previously developed is obtained. We extract the relative importance of the different exchange mechanisms included in the meson picture by means of a comparison to the corresponding operational structures appearing in the effective approach. The ability of this procedure to obtain the weak baryon-baryon-meson couplings for a possible scalar exchange is also discussed.

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The relation between the low-energy constants appearing in the effective field theory description of the Lambda N -> NN transition potential and the parameters of the one-meson-exchange model previously developed is obtained. We extract the relative importance of the different exchange mechanisms included in the meson picture by means of a comparison to the corresponding operational structures appearing in the effective approach. The ability of this procedure to obtain the weak baryon-baryon-meson couplings for a possible scalar exchange is also discussed.

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Recent studies show that the composition of fingerprint residue varies significantly from the same donor as well as between donors. This variability is a major drawback in latent print dating issues. This study aimed, therefore, at the definition of a parameter that is less variable from print to print, using a ratio of peak area of a target compound degrading over time divided by the summed area of peaks of more stable compounds also found in latent print residues.Gas chromatography-mass spectrometry (GC/MS) analysis of the initial lipid composition of latent prints identifies four main classes of compounds that can be used in the definition of an aging parameter: fatty acids, sterols, sterol precursors, and wax esters (WEs). Although the entities composing the first three groups are quite well known, those composing WEs are poorly reported. Therefore, the first step of the present work was to identify WE compounds present in latent print residues deposited by different donors. Of 29 WEs recorded in the chromatograms, seven were observed in the majority of samples.The identified WE compounds were subsequently used in the definition of ratios in combination with squalene and cholesterol to reduce the variability of the initial composition between latent print residues from different persons and more particularly from the same person. Finally, the influence of a latent print enhancement process on the initial composition was studied by analyzing traces after treatment with magnetic powder, 1,2-indanedione, and cyanoacrylate.

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The objective of this work was to evaluate the use of basic density and pulp yield correlations with some chemical parameters, in order to differentiate an homogeneous eucalyptus tree population, in terms of its potential for pulp production or some other technological applications. Basic density and kraft pulp yield were determined for 120 Eucalyptus globulus trees, and the values were plotted as frequency distributions. Homogenized samples from the first and fourth density quartiles and first and fourth yield quartiles were submitted to total phenols, total sugars and methoxyl group analysis. Syringyl/guaiacyl (S/G) and syringaldehyde/vanillin (S/V) ratios were determined on the kraft lignins from wood of the same quartiles. The results show the similarity between samples from high density and low yield quartiles, both with lower S/G (3.88-4.12) and S/V (3.99-4.09) ratios and higher total phenols (13.3-14.3 g gallic acid kg-1 ). Woods from the high yield quartile are statistically distinguished from all the others because of their higher S/G (5.15) and S/V (4.98) ratios and lower total phenols (8.7 g gallic acid kg-1 ). Methoxyl group and total sugars parameters are more adequate to distinguish wood samples with lower density.

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The relationship between pressure induced changes on individual proteins and selected quality parameters in bovine longissimus thoracis et lumborum (LTL) muscle was studied. Pressures ranging from 200 to 600 MPa at 20 °C were used. High pressure processing (HPP) at pressures above 200 MPa induced strong modifications of protein solubility, meat colour and water holding capacity (WHC). The protein profiles of non-treated and pressure treated meat were observed using two dimensional electrophoresis. Proteins showing significant differences in abundance among treatments were identified by mass spectrometry. Pressure levels above 200 MPa strongly modified bovine LTL proteome with main effects being insolubilisation of sarcoplasmic proteins and solubilisation of myofibrillar proteins. Sarcoplasmic proteins were more susceptible to HPP effects than myofibrillar. Individual protein changes were significantly correlated with protein solubility, L*, b* and WHC, providing further insights into the mechanistic processes underlying HPP influence on quality and providing the basis for the future development of protein markers to assess the quality of processed meats.

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Multiple motor function and strength assessment tools exist for the evaluation of neuromuscular diseases, but most do not directly assess functional ability in the patients' daily physical activity in their home environment. In this study our aim was to assess: 1) the feasibility and accuracy of physical activity monitoring during two days in a home environment of five DMD patients using a non-commercialized monitor containing a 3D accelerometer and a gyroscope, 2) if a difference in the physical activity parameters could be measured before and one month after starting prednisolone. We reliably quantified the time spend sitting, standing, lying, walking, the number of steps taken, the cadence, the number of walking episodes and their duration as well as how these were distributed over the day. Parameters possibly reflecting endurance, such as the duration of the walking episodes or the succession of two or three walking episodes lasting more than 30 s were the most improved after prednisolone treatment. This degree of detailed determination of physical activity in a home environment has not been previously reported in neuromuscular disorders to our knowledge and some of the reported parameters are potential new outcome measures in clinical trials.

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The objective of this work was to evaluate hematological, biochemical and ruminant parameters for diagnosis and treatment of the left displaced abomasum (LDA) in dairy cows, in the Plateau Region of Rio Grande do Sul, Brazil. Ruminant fluid, blood and urine samples were collected from 20 cows suffering LDA and from 20 healthy cows (control). The cows with LDA showed lower values of daily milk production, body weight and corporal condition score. The use of pH reagent strips showed to be functional in the field, when compared to a digital pH meter. Ruminant dynamics was damaged in cows affected by LDA, as it was evidenced by the higher reduction time of methylene blue. Serum values of lactate, beta-hydroxybutyrate, urea, albumin, free fatty acids and cholesterol shows to be auxiliary tools in the LDA characterization.