Short-lived spots in solar-like stars as observed by CoRoT

Context. CoRoT light curves have an unprecedented photometric quality, having simultaneously a high signal-to-noise ratio, a long time span and a nearly continuous duty-cycle. Aims. We analyse the light-curves of four bright targets observed in the seismology field and study short-lived small spots in solar-like stars. Methods. We present a simple spot modeling by iterative analysis. Its ability to extract relevant parameters is ensured by implementing relaxation steps to avoid convergence to local minima of the sum of the residuals between observations and modeling. The use of Monte-Carlo simulations allows us to estimate the performance of the fits. Results. Our starspot modeling gives a representation of the spots on these stars in agreement with other well tested methods. Within this framework, parameters such as rigid-body rotation and spot lifetimes seem to be precisely determined. Then, the lifetime/rotation period ratios are in the range 0.5 - 2, and there is clear evidence for differential rotation.Comment: 11 pages Accepted in A&

Searching for star-planet magnetic interaction in CoRoT observations

Close-in massive planets interact with their host stars through tidal and magnetic mechanisms. In this paper, we review circumstantial evidence for star-planet interaction as revealed by the photospheric magnetic activity in some of the CoRoT planet-hosting stars, notably CoRoT-2, CoRoT-4, and CoRoT-6. The phenomena are discussed in the general framework of activity-induced features in stars accompanied by hot Jupiters. The theoretical mechanisms proposed to explain the activity enhancements possibly related with hot Jupiter are also briefly reviewed with an emphasis on the possible effects at photospheric level. The unique advantages of CoRoT and Kepler observations to test these models are pointed out.Comment: Invited review paper accepted by Astrophysics and Space Science, 13 pages, 5 figure

Equivalence of the long-wavelength approximation and the truncated Taylor expansion in relativistic Coulomb excitation

The long-wavelength approximation and the truncated Taylor expansion are frequently used in the theory of relativistic Coulomb excitation to obtain multipole expansions of the interaction. It is shown in this note that these two approximations are exactly equivalent.Comment: 5 page

Daytime tropospheric loss of hexanal and <I>trans</I>-2-hexenal: OH kinetics and UV photolysis

International audienceThe ultraviolet (?=250?370 nm) photolysis and the OH-initiated oxidation of hexanal and trans-2-hexenal, which are relevant atmospheric processes, have been investigated at room temperature and as a function of temperature (T=263?353 K), respectively. This kinetic study as a function of temperature is reported here for the first time. Absolute absorption cross sections (??) were obtained using a recently built system operating in the UV region. The obtained ?? allowed the estimation of the photolysis rates (J) across the troposphere. Kinetic measurements of the gas-phase reaction of hydroxyl radicals (OH) with hexanal and trans-2-hexenal were performed by using the laser pulsed photolysis/laser-induced fluorescence technique. Rate coefficients kOH for both aldehydes were determined at temperatures between 263 and 353 K at 50 Torr in helium or argon bath gases. The temperature dependence of kOH for both aldehydes was found to be slightly negative. The tropospheric lifetime of hexanal and trans-2-hexenal due to the chemical removal by OH radicals has been estimated across the troposphere. The loss rate due to the OH chemical removal was compared with the estimated photolysis rates. Our results show that OH-reaction is the main loss process for these aldehydes in the troposphere, although photolysis is not negligible for hexanal

Efectos de la maduración y el procesamiento sobre la calidad nutricional y sensorial de las aceitunas de mesa Itrana

In the present study, we evaluated the nutritional and sensory characteristics of table olives of the Italian doubleaptitude olive cultivar (Olea europaea L. cv. Itrana) processed as green (Oliva bianca di Itri) and black (Oliva di Gaeta) table olives with modified Greek methods of preparation. One method provides an initial step of immersion in water to stimulate the growth of specific microflora which contributes to the debittering of the fruits. After 15-45 days, salt is added to the liquid in quantities not exceeding 8 kg per 100 kg of fresh olives. Another method entails the immersion of fruits directly in brine utilizing double-salting (half the amount of NaCl was added immediately and the remaining part after 15 days). All the information derived from chemico-physical, nutritional and sensory data have separated the samples into four groups according to techno-processings, ripening stage and storage. Double-salting is the method which assures the best results.En el presente estudio se evalúan las características nutricionales y sensoriales de la variedad Itrana de aceituna (Olea europaea L.) de doble uso, elaborada en verde (Oliva Bianca di Itri) y en negro (Oliva di Gaeta), utilizando métodos griegos modificados al efecto. Un método consiste en una etapa inicial de inmersión en agua para favorecer el crecimiento de una flora específica que contribuye al endulzado de los frutos. Después de 15-45 días se añade sal a la solución en una cantidad que no exceda 8 kg por 100 g de fruto fresco. Otro procedimiento consiste en colocar directamente las aceitunas en salmuera utilizando un sistema de adición de la sal en dos etapas (la mitad de la sal se añade inmediatamente y el resto a los 15 días). Toda la información derivada de los análisis fisico-químicos, nutricionales y sensoriales ha permitido la separación de las muestras en cuatro grupos según la tecnología de elaboración, el estado de madurez y el almacenamiento. El proceso de adición de sal en dos etapas (“double salting”) fue el procedimiento que dio mejores resultados

Diversity and Ecology of Diatoms in Northwest of Algeria: case of El-Hammam stream and Estuary of Cheliff River

P. 37-52Ecological research on algae from Algeria and in particular on freshwater and estuarine diatoms remains insufficient. The aim of our work is to contribute to the taxonomy and ecology of benthic diatoms from freshwaters and estuaries in Algeria. For this purpose, we studied two sites of water courses in north-western Algeria: El-Hammam stream at Mascara and the estuary of Cheliff river at Mostaganem. Our inventory of benthic diatoms during dry season at the middle of El-Hammam stream during April, June and August 2010 led to the identification of 44 cosmopolitan species, while 30 species occurred at the mouth of Cheliff river. 10 taxa were recorded for the first time in Algeria. Diversity values (Species richness, Shannon's index and Equitability index) for the two study sites are generally medium to low. The results of the 17 diatom-based metrics tested show that ROTT trophic index (TID) and the Trophic Diatom Index (TDI) best mirrored water quality, but a revision of taxa autecological values is requiredS

Machine learning based activity recognition to identify wasteful activities in production

Lean Management focusses on the elimination of wasteful activities in production. Whilst numerous methods such as value stream analysis or spaghetti diagrams exist to identify transport, inventory, defects, overproduction or waiting, the waste of human motion is difficult to detect. Activity recognition attempts to categorize human activities using sensor data. Human activity recognition (HAR) is already used in the consumer domain to detect human activities such as walking, climbing stairs or running. This paper presents an approach to transfer the human activity recognition methods to production in order to detect wasteful motion in production processes and to evaluate workplaces. Using sensor data from ordinary smartphones, long-term short-term memory networks (LSTM) are used to classify human activities. Additional to the LSTM-network, the paper contributes a labeled data set for supervised learning. The paper demonstrates how activity recognition can be included in learning factory training starting from the generation of training data to the analysis of the results