Non-Gaussianity in the Cosmic Microwave Background Induced by Dipolar Dark Matter

In previous work [L. Blanchet and A. Le Tiec, Phys. Rev. D 80, 023524 (2009)], motivated by the phenomenology of dark matter at galactic scales, a model of dipolar dark matter (DDM) was introduced. At linear order in cosmological perturbations, the dynamics of the DDM was shown to be identical to that of standard cold dark matter (CDM). In this paper, the DDM model is investigated at second order in cosmological perturbation theory. We find that the internal energy of the DDM fluid modifies the curvature perturbation generated by CDM with a term quadratic in the dipole field. This correction induces a new type of non-Gaussianity in the bispectrum of the curvature perturbation with respect to standard CDM. Leaving unspecified the primordial amplitude of the dipole field, which could in principle be determined by a more fundamental description of DDM, we find that, in contrast with usual models of primordial non-Gaussianities, the non-Gaussianity induced by DDM increases with time after the radiation-matter equality on super-Hubble scales. This distinctive feature of the DDM model, as compared with standard CDM, could thus provide a specific signature in the CMB and large-scale structure probes of non-Gaussianity.Comment: 20 pages; v2: extended discussion in Sec. V D, added references; matches published versio

Étude de la variation spatio-temporelle du couvert nival par télédétection micro-ondes passives et validation du Modèle Régional Canadien du Climat (MRCC)

The spatial/temporal variation of the snow cover is simulated by many models such as the Canadian Regional Climate Model (CRCM) developed by Université du Quebec à Montréal that simulates the snow water equivalent (SWE), a key parameter for hydrological cycle investigation. Better understanding of snow cover dynamics and the validation of these models suffer from the space observational record available and passive microwave satellite data and appears as a very useful tool for such an objective.The data are derived from the daily Special Sensor Microwave/Imager (SSM/I) data from the DMSP satellite series and also in the Northern Hemisphere Weekly Snow Cover and Ice Extent from the NSIDC in the EASE-Grid format. A threshold adapted for four vegetation density classes (Canadian Landcover 1km-resolution image) is applied to the normalized difference brightness temperature signal between 37GHz and 19GHz to extract snow cover. This satellite database is available since 1987, however, the analysis has been carried out between August 1992 and June 1995 over Eastern Canada corresponding the CRCM run simulation driven by NCEP atmospheric objective analysis.The results shows that the model is underestimating snow cover, the winter season tends to arrive later when compared to SSM/I and spring is arriving too early. For the study area, the CRCM is modelling snow cover with an error of 9.3%. Locally, this error can be as large as 30-40%. This thesis shows the potential of satellite microwave data for comprehensive spatial and temporal evaluation of model behavior

Branon stabilization from fermion-induced radiative corrections

We consider a 3-brane embedded in 5-dimensional space time characterized by a Gaussian warp factor, for which the four-dimensional effective theory for brane fluctuation (branons) is unstable. We show that radiative corrections arising from fermions living on the brane, and therefore coupled to branons, stabilize the system by generating dynamically a spontaneous symmetry breaking for the branon field. The price to pay, for the corresponding mechanism to be consistent, is to have a large number of fermion flavours, and we discuss the fat brane scenario as an interpretation for the dressed branon theory, taking into account the Maxwell construction, which avoids the spinodal instability present in the perturbative effective potential.Comment: 7 page

Progrès vers l’identification de la phéromone sexuelle de la cécidomyie du sapin Paradiplosis tumifex Gagné (Diptera : Cecidomyiidae)

La cécidomyie du sapin, Paradiplosis tumifex Gagné (Diptera : Cecidomyiidae), est un ravageur important du sapin baumier puisqu’il cause la sénescence prématurée des aiguilles ce qui diminue sa valeur esthétique comme arbre de Noël. Notre objectif est d’élucider la structure chimique de la phéromone sexuelle émise par la femelle pour l’utiliser dans un piège à phéromone comme outil de dépistage. Ainsi, nous avons collecté les effluves des femelles et des mâles où, en les analysant par chromatographie en phase gazeuse, un signal ayant seulement été observé chez les femelles pourrait correspondre à la phéromone. À l’aide des similarités entre les structures de celles connues chez 17 autres espèces de cécidomyies, nous avons synthétisé des analogues dont les indices de rétention ont été comparés à la phéromone afin d’aider à son identification. Finalement, bien que la structure n’ait pas été établie, les options disponibles pour atteindre notre but ont été exposées.The balsam gall midge, Paradiplosis tumifex Gagné (Diptera: Cecidomyiidae), is a significant pest of the balsam fir causing premature needle senescence, which diminishes its aesthetic value as a Christmas tree. Our goal is to elucidate the female-produced sex pheromone chemical structure to use it in a pheromone trap as a monitoring tool. Thus, we collected female and male effluents where, by analysing them using gas chromatography, a signal shown exclusively in females was observed. Using structural similarities of sex pheromones known for 17 other cecidomyiidae species, we synthesized analogues for which retention indexes were compared to the pheromone to help its identification. Finally, even though the structure has not been determined, the available alternatives to reach our target were discussed

Why do we watch? The role of emotion gratifications and individual differences in predicting rewatchability and movie recommendation

Background: The present study’s main aim was to determine the predictors of movie rewatchability and recommendations. Methods: Using a sample of 318 participants, we first tested the structure of a gratification scale from watching a movie. Then, we examined the role of age, need for cognition, need for affect, extraversion, and emotional gratifications, in predicting individuals’ interest in rewatching the movie and in making recommendations. Results: As in the original proposal of the emotional gratification scale, the following dimensions were identified: fun, thrill, empathic sadness, release of emotions, social sharing, contemplative experiences, and character engagement, with acceptable model fit and reliability, convergent and divergent validity. Social sharing, contemplate experiences, need for affect and age were significant predictors of movie recommendation; whereas social sharing, thrill, extraversion, and age contributed most to explaining rewatching interest. Conclusion: This study highlights the importance of considering distinct gratifications and individual differences in predicting rewatching and movie recommendation.info:eu-repo/semantics/publishedVersio

Microwave dielectric study of spin-Peierls and charge ordering transitions in (TMTTF)2_2PF6_6 salts

We report a study of the 16.5 GHz dielectric function of hydrogenated and deuterated organic salts (TMTTF)$_2$PF$_6$. The temperature behavior of the dielectric function is consistent with short-range polar order whose relaxation time decreases rapidly below the charge ordering temperature. If this transition has more a relaxor character in the hydrogenated salt, charge ordering is strengthened in the deuterated one where the transition temperature has increased by more than thirty percent. Anomalies in the dielectric function are also observed in the spin-Peierls ground state revealing some intricate lattice effects in a temperature range where both phases coexist. The variation of the spin-Peierls ordering temperature under magnetic field appears to follow a mean-field prediction despite the presence of spin-Peierls fluctuations over a very wide temperature range in the charge ordered state of these salts.Comment: 7 pages, 6 figure

Use of especials radiographic positioners in endodontic procedure: Case report

The aim was to review the literature about the use of radiographic positioners in endodontic procedures and to report a clinic case in what this equipment was used. Getting images of quality and without distortions is important, because is necessary knowing the dental anatomy and the adjacent structures. For precise x-rays, it is necessary to correctly locate the X-ray film, angulations and distance of the cylinder with aid of radiographic positioners, which stabilizes the angulations, simplifying the technique. The option for RH positioner for radiographies under total isolation (Indusbello®) during endodontic procedures facilitates de exam and keeps the absolute isolation, giving space for de endodontic file in the radicular canal. The use of this positioner minimizes the errors and facilitates the taking of standardized images and bring more safety to endodontic treatment

Salivary and dental parameters of Down Syndrome subjects in a city of Rio Grande do Sul

The present study analyzed the salivary parameters, such as ph, buffer capacity and salivary flow and also the DMF index of an institutionalized Down Syndrome (DS) group. The sample consisted of fifteen subjects from both sexes and variable ages, seven subjects with DS from APAE (Associação de Pais e Amigos dos Excepcionais) and AFAD (Associação Familiares e Amigos do Down), both from Cachoeira do Sul in Rio Grande do Sul (Brazil), and eight subjects without Down Syndrome from ULBRA in Cachoeira do Sul. In relation to the salivary parameters, the flow and the ph did not present alterations when compared to the control group. The buffer capacity was statistically less efficient in the saliva of the individuals with the Down syndrome. The DMF index of the individuals with the Down syndrome and of the individuals with no Down syndrome did not present differences

Les stages à l’international : un outil pédagogique d’apprentissage authentique

Comprend des références bibliographiques et webographiquesProjet de recherche financé par PARE