Feedback control of unstable cellular solidification fronts

We present a feedback control scheme to stabilize unstable cellular patterns during the directional solidification of a binary alloy. The scheme is based on local heating of cell tips which protrude ahead of the mean position of all tips in the array. The feasibility of this scheme is demonstrated using phase-field simulations and, experimentally, using a real-time image processing algorithm, to track cell tips, coupled with a movable laser spot array device to heat the tips locally. We demonstrate, both numerically and experimentally, that spacings well below the threshold for a period-doubling instability can be stabilized. As predicted by the numerical calculations, cellular arrays become stable with uniform spacing through the feedback control which is maintained with minimal heating.

Nanometer-scale oxidation of Si(100) surfaces by tapping mode atomic force microscopy

The nanometer¿scale oxidation of Si(100) surfaces in air is performed with an atomic force microscope working in tapping mode. Applying a positive voltage to the sample with respect to the tip, two kinds of modifications are induced on the sample: grown silicon oxide mounds less than 5 nm high and mounds higher than 10 nm (which are assumed to be gold depositions). The threshold voltage necessary to produce the modification is studied as a function of the average tip¿to¿sample distance.

L 'évolution des réserves énergétiques chez les ouvrières et les sexués de la fourmi d 'Argentine (Iridomyrmex humilis) (Mayr): une stratégie en relation avec le mode de fondation

Le poids sec, le rapport corps gras/poids sec et le contenu énergétique ou dernier stade larvaire. de le nymphe et de l'adulte ont été mesurés chez les reines. Les mâles et les ouvrières de la fourmi d'Argentine, une espèce caractérisée par une fondation de type dépendant. Deux principaux résultats ont été obtenus. En ce qui concerne les reines, nous avons montré qu'il existe une accumulation du corps gras entre l'émergence et l'accouplement toutefois cette augmentation du contenu énergétique se révèle moins importante chez cette espèce que chez celles qui possèdent une fondation de type indépendant. L'intérêt adaptatif de cette différence est discuté. En ce qui concerne les ouvrières adultes, c'est au moment de l'émergence que nous avons rencontré le plus de corps gras. En vieillissant les ouvrières perdent de l'énergie. On peut penser que ces variations sont en relation avec les tâches accomplies par les ouvrières, à l'rintéheur et à l'extérieur du nid.

Physiologie des sexués femelles de fourmis (Hymenoptera; Formicidae) en relation avec le mode de fondation

A study was undertaken to determine if there was a relation between the mode of colony founding in ants and the physiology of the new queens produced, in which mature gynes of 24 ant species were examined. Gynes of species utilizing independent colony founding had a far higher relative fat content (X±SD; 54±6%)(g fat/g dry weight) than gynes of species employing dependent colony founding(19±8%). Dimorphism between queens and workers was significantly higher in species employing independent colony founding. Thus independent colony founding not only results in production of queens with a relatively higher fat content and therefore with a higher energy content per g, but also results in the production of larger queens (in comparison with worker size). Of species employing independent colony founding, 80% were monogynous, whereas only 11% of the species employing dependent colony founding were monogynous. These results are discussed with regard to the social structure and life-history of ant species.

Smith Predictor Sliding Mode Closed-loop Glucose Controller in Type 1 Diabetes

Type 1 diabetic patients depend on external insulin delivery to keep their blood glucose within near-normal ranges. In this work, two robust closed-loop controllers for blood glucose regulation are developed to prevent the life-threatening hypoglycemia, as well as to avoid extended hyperglycemia. The proposed controllers are designed by using the sliding mode control technique in a Smith predictor structure. To improve meal disturbance rejection, a simple feedforward controller is added to inject meal-time insulin bolus. Simulations scenarios were used to test the controllers, and showed the controllers ability to maintain the glucose levels within the safe limits in the presence of errors in measurements, modeling and meal estimation

Le bon vin d’Orleans, le punays lac de Sorbone et la mode de Bretaigne: sociocentrisme lúdic i ambivalència als blasons populars del Pantagruel de Rabelais, amb mostres de versions en diferents llengües

En aquest article es presenta una selecció d’un corpus extret del Pantagruel, en el qual els personatges de Rabelais ataquen o afalaguen, grotescament i hiperbòlica, en el més pur estil pantagruèlic, les altres nacions o viles. Per a aquests epítets ètnics, Rabelais reutilitza el blasó popular (blason populaire), en una fusió total de la lloança i la injúria. En el nostre treball comprovarem si la visió sociocèntrica que el blasonador aplica al blasonat, així com el propòsit lúdic, han aconseguit ser traslladats a les versions catalana (Miquel-Àngel Sánchez Férriz, 1985), espanyola (Alicia Yllera, 2003), italiana (Mario Bonfantini, 1953) i anglesa (Burton Raffel, 1991).

Empirical mode decomposition-based face recognition system

In this work we explore the multivariate empirical mode decomposition combined with a Neural Network classifier as technique for face recognition tasks. Images are simultaneously decomposed by means of EMD and then the distance between the modes of the image and the modes of the representative image of each class is calculated using three different distance measures. Then, a neural network is trained using 10- fold cross validation in order to derive a classifier. Preliminary results (over 98 % of classification rate) are satisfactory and will justify a deep investigation on how to apply mEMD for face recognition.

EEG signal analysis via a cleaning procedure based on multivariate empirical mode decomposition

Artifacts are present in most of the electroencephalography (EEG) recordings, making it difficult to interpret or analyze the data. In this paper a cleaning procedure based on a multivariate extension of empirical mode decomposition is used to improve the quality of the data. This is achieved by applying the cleaning method to raw EEG data. Then, a synchrony measure is applied on the raw and the clean data in order to compare the improvement of the classification rate. Two classifiers are used, linear discriminant analysis and neural networks. For both cases, the classification rate is improved about 20%.

Enquête sur la mode féminine : [plaquette de prestige] / High-Life Taylor ; [texte signé J.R.] ; [ill. de Bernard B. de Monvel, Maurice Leloir, L. Sabattier,...]

Mécénat texte imprimé : Cet ouvrage a été numérisé grâce à Myriam Lenourry