Thermal phase diagrams of columnar liquid crystals

In order to understand the possible sequence of transitions from the disordered columnar phase to the helical phase in hexa(hexylthio)triphenylene (HHTT), we study a three-dimensional planar model with octupolar interactions inscribed on a triangular lattice of columns. We obtain thermal phase diagrams using a mean-field approximation and Monte Carlo simulations. These two approaches give similar results, namely, in the quasi one-dimensional regime, as the temperature is lowered, the columns order with a linear polarization, whereas helical phases develop at lower temperatures. The helicity patterns of the helical phases are determined by the exact nature of the frustration in the system, itself related to the octupolar nature of the molecules.Comment: 12 pages, 9 figures, ReVTe

Innovación en Cartografía y Fotointerpretación digital: retos y resultados

En los últimos años la Cartografía ha experimentado profundos cambios gracias al uso de la informática. Actualmente, los procesos cartográficos pueden realizarse con ordenadores pero su incorporación a las aulas universitarias ha sido muy dispar debido a los elevados costes o a la falta de formación específica del profesorado. “Cartografía y Fotointerpretación” es una asignatura obligatoria de primer ciclo que se imparte en las licenciaturas de Geografía y de Ciencias Ambientales de la Universidad Autónoma de Barcelona. Dentro de los principales retos de la asignatura fruto de los cambios tecnológicos comentados o a consecuencia del proceso de convergencia al EEES, la transformación de las prácticas en formato analógico (en papel) a formato digital (con ordenador) aparece como uno de los requisitos de obligado cumplimiento. El proyecto de innovación presentado tiene como objetivo profundizar en esta transformación y se basa en los siguientes bloques: 1. Uso de un programa informático gratuito, MiraMon, muy útil por los siguientes motivos: es un programa de prestaciones totalmente profesionales pero gratuito para el alumnado; es un de fácil manejo; y es capaz de leer un elevado número de formatos. 2. Las prácticas se realizan en las aulas con recursos informáticos, con un doble objetivo: captación desde Internet del material digital necesario y almacenamiento de los resultados en una carpeta de acceso exclusivo para el alumno. 3. Espacio de consulta y atención al alumno. En el Campus Virtual, los alumnos tienen acceso al material didáctico y pueden consultar cualquier duda directamente con el profesor. Los resultados han sido, hasta la fecha, muy positivos, produciéndose, además, un estimable ahorro de papelSIN FINANCIACIÓNNo data 200

Design of an Adaptive Fuzzy Control System for Dual Star Induction Motor Drives

In this paper, a new control stra¬tegy is deve¬loped; an adaptive fuzzy controller based on Lyapunov's stability theory (AFLC) recalculates the real-time PI-fuzzy gains and combines the advantages of two robust techniques i.e. the fuzzy logic control and the adaptive one. For the new adaptive fuzzy control, we followed two steps: in the first one, a PI-fuzzy controller is designed, in the second step, the gains of a fuzzy regulator are determined. Extensive simulation results are presented to validate the proposed technique. The system is tested at different speeds and a very satisfactory performance has been achieved

Etude théorique de la structure de bande du graphite par une méthode de potentiels effectifs et par une méthode E. H. T. modifiée

Le calcul de la bande d'énergie d'un plan graphitique par une méthode d'hamilthoniens effectifs et par une méthode de type EHT conduit à des résultats satisfaisants et compte-tenu de leur simplicité permet d'envisager leur utilisation pour des systèmes plus complexes tels que les composés d’insertion du graphite

Etude théorique sur les atomes de carbone interstitiels dans le graphite

L'analyse du couplage d'un atome de carbone interstitiel avec la bande II d’un réseau graphitique au moyen du formalisme des fonctions de Green montre l'existence d'un maximum correspondant à la position admise pour de tels atomes. L'existence de ce maximum est liée simplement à l'évolution de l'intégrale de recouvrement entre l’orbitale sp du carbone interstitiel et les orbitales 2pz des atomes voisins des plans graphitiques

On the interest of the spectral bands in the automatic selection of high quality MODIS data through spatial pattern identification.

MODIS (MODerate resolution Imaging Spectroradiometer) daily surface reflectance data is distributed with one of the most complete quality ancillary data sets. Such amount of quality information is essential for automatically selecting the highest quality MODIS daily images, for example using geostatistical analysis of the image spatial pattern. However, the success of this automatic selection certainly could depend on the spectral information of each MODIS band. This work studies the influence of MODIS spectral bands on the automatic identification of high quality daily images by analyzing their variogram and aiming at the identification of the most suitable spectral band (or band combination) for the spatial characterization of a given geographical region. The analysis tests the influence of each of the reflectance bands of the 2009 MOD09GA Daily Surface Reflectance product and the first component of its Principal Component Analysis over an area of 32 000 km2 , Catalonia (northeast of the Iberian Peninsula). Specifically, the combination of quality data and the variogram analysis allows the detection of different anomalies by the correspondence between the variability among the pixels and the fitted variogram parameters: nugget, sill and range. The variogram analysis is reaffirmed as an extremely useful approach for the automatic selection of high quality images while highlighting the need of high computational techniques for such huge processing. Finally, it reveals that is crucial to select the appropriate spectral band in order to, not only optimize, but substantially improve the automatic selection of remote sensing images using geostatistical analysis based on variogram tools

Evaluation of the plantaris tendon: cadaver anatomy study with ultrasonographic and clinical correlation with tennis leg injury in 759 calves.

International audienceThe role of the plantaris muscle (PM) in the literature is not clear. The objectives of this study were as follows: (1) to study PM at the interface between the medial gastrocnemius and soleus muscle in a cadaveric series, (2) to compare anatomic results with ultrasound (US) in the general population, and (3) to identify the potential role of the PM in the genesis of tennis leg (TL) injury. First, a cadaveric study was undertaken on six cadavers for descriptive and functional PM anatomy. Second, US evaluation was carried out for 670 calves in 335 subjects with no suspicion of a clinical tear in the thigh or calf muscle (group 1) and for 89 calves in 89 patients with tear symptoms (group 2). Study criteria were the presence or absence of PM tendon and the width measurement if present. The PM was present in all cadavers. Traction on the tendon showed its "limited" mobility due to the connective tissue adherence mentioned with no apparent gliding of PM, promoting TL injury. In US, 37 PM were absent (4.35%) in 23 subjects. PM tendon width measurement of group 1 and group 2 was, respectively, 3.93 + / - 1.10 mm and 3.96 + / - 1.10 mm. No statistically significant differences between width measurements were found according to side (P = 0.74) or group (P = 0.69). Significant differences in width were only found between genders in group 1 (P = 0.014). PM were absent in 4.35% population. The contraction of PM can promote tennis leg injury by increasing the shear forces at the level of the distal inter-aponeurotic region

Skeletal Radiol

The role of the plantaris muscle (PM) in the literature is not clear. The objectives of this study were as follows: (1) to study PM at the interface between the medial gastrocnemius and soleus muscle in a cadaveric series, (2) to compare anatomic results with ultrasound (US) in the general population, and (3) to identify the potential role of the PM in the genesis of tennis leg (TL) injury. First, a cadaveric study was undertaken on six cadavers for descriptive and functional PM anatomy. Second, US evaluation was carried out for 670 calves in 335 subjects with no suspicion of a clinical tear in the thigh or calf muscle (group 1) and for 89 calves in 89 patients with tear symptoms (group 2). Study criteria were the presence or absence of PM tendon and the width measurement if present. The PM was present in all cadavers. Traction on the tendon showed its "limited" mobility due to the connective tissue adherence mentioned with no apparent gliding of PM, promoting TL injury. In US, 37 PM were absent (4.35%) in 23 subjects. PM tendon width measurement of group 1 and group 2 was, respectively, 3.93 + / - 1.10 mm and 3.96 + / - 1.10 mm. No statistically significant differences between width measurements were found according to side (P = 0.74) or group (P = 0.69). Significant differences in width were only found between genders in group 1 (P = 0.014). PM were absent in 4.35% population. The contraction of PM can promote tennis leg injury by increasing the shear forces at the level of the distal inter-aponeurotic region