Invariance quantum groups of the deformed oscillator algebra

A differential calculus is set up on a deformation of the oscillator algebra. It is uniquely determined by the requirement of invariance under a seven-dimensional quantum group. The quantum space and its associated differential calculus are also shown to be invariant under a nine generator quantum group containing the previous one.Comment: 13 pages, Late

Weather on Other Worlds. II. Survey Results: Spots Are Ubiquitous on L and T Dwarfs

We present results from the "Weather on Other Worlds" Spitzer Exploration Science program to investigate photometric variability in L and T dwarfs, usually attributed to patchy clouds. We surveyed 44 L3-T8 dwarfs, spanning a range of $J-K_s$ colors and surface gravities. We find that 14/23 (61%; 95% confidence interval: 41%-78%) of our single L3-L9.5 dwarfs are variable with peak-to-peak amplitudes between 0.2% and 1.5%, and 5/16 (31%; 95% confidence interval: 14%-56%) of our single T0-T8 dwarfs are variable with amplitudes between 0.8% and 4.6%. After correcting for sensitivity, we find that 80% (95% confidence interval: 53%-100%) of L dwarfs vary by >0.2%, and 36% (95% confidence interval: 19%-52%) of T dwarfs vary by >0.4%. Given viewing geometry considerations, we conclude that photospheric heterogeneities causing >0.2% 3-5-micron flux variations are present on virtually all L dwarfs, and probably on most T dwarfs. A third of L dwarf variables show irregular light curves, indicating that L dwarfs may have multiple spots that evolve over a single rotation. Also, approximately a third of the periodicities are on time scales >10 h, suggesting that slowly-rotating brown dwarfs may be common. We observe an increase in the maximum amplitudes over the entire spectral type range, revealing a potential for greater temperature contrasts in T dwarfs than in L dwarfs. We find a tentative association (92% confidence) between low surface gravity and high-amplitude variability among L3-L5.5 dwarfs. Although we can not confirm whether lower gravity is also correlated with a higher incidence of variables, the result is promising for the characterization of directly imaged young extrasolar planets through variability.Comment: 42 pages, 11 figures, 2 tables, accepted by Ap

Une classe de fonctions de Wigner adaptées à la description du rayonnement acoustique

L'objet de cette communication est l'introduction d'une classe de fonctions de Wigner adaptées à la description de signaux acoustiques dépendant de deux variables, position et temps. Ces fonctions généralisent les distributions temps-fréquence affines de type Pk et conduisent, en particulier, à représenter des signaux relevés sur une droite dans un espace à quatre dimensions (temps, position, fréquences spatiale et temporelle). La méthode de construction est fondée sur l'introduction d'un groupe de covariance adapté. Elle permet d'obtenir sous forme explicite des représentations d'espace des phases dont on peut étudier les propriétés de localisation

Characterization of SU(1,1) coherent states in terms of affine group wavelets

The Perelomov coherent states of SU(1,1) are labeled by elements of the quotient of SU(1,1) by the compact subgroup. Taking advantage of the fact that this quotient is isomorphic to the affine group of the real line, we are able to parameterize the coherent states by elements of that group or equivalently by points in the half-plane. Such a formulation permits to find new properties of the SU(1,1) coherent states and to relate them to affine wavelets.Comment: 11 pages, latex, to be published in J. Phys. A : Math. Ge

Pattern of venous thromboembolic diseases in a resources-limited setting in Cameroon

Introduction: Admission for a medical illness is associated with an increased risk of venous thrombo-embolism; however reports addressing at this issue are rare in Cameroon. We sought to assess the pattern of thrombo-embolism among in-medical patients of a semi-urban hospital. Methods: We prospectively included 79 hospitalized medical patients of the Military Hospital of Bamenda (north-west region-Cameroon). From July 2010 and December 2013, we collected baseline demographic data, risk factors of venous thromboembolism, clinical presentation, diagnostic process and treatment. Results: In the 1445 patients admitted for medical illnesses, a total of 79 venous thrombo-embolic diseases were detected (55 deep vein thrombosis, 14 pulmonary embolism, 9 post-phlebitic syndrome and 1 cerulae alba dolens). The leading risk factors were prolonged immobilization (100%), age > 40 years (78.9%), obesity (43%), long distance travel (30.4%) and HIV-AIDS (21.5%). Thirty one (40.5%) had ≤ 2 cumulative risk factors, and 8 (10.1%) more than 4. All the patients in the group had a significant risk of deep vein thrombosis: 5 (6.3%), 34 (43%) and 40 (50.6%) with moderate, high and very high risk respectively. Increasing number of deep vein thrombosis was associated with increasing level of the risk and the clinical probability scores. Lower limb location of deep vein thrombosis was the most frequent with 75 (94.9%) cases. Almost all the patients received appropriate therapy with heparin and oral anticoagulant during their hospital stay. The mean length of hospital stay was 17.5 +/-15 (range 4- 62) days; disability and death occurred in 15 (19%) and 17 (21.5%) respectively. Conclusion: Venous thromboembolism is also a common concern in a semi-urban practice of our country. Long distance travel, one of the leading risk factors merits to be more specifically studied.Pan African Medical Journal 2016; 2

Profils motivationnels à l’entrée en Faculté ou en IUT et réussite académique des étudiants

Cette étude vise à identifier les caractéristiques motivationnelles (théorie de l’autodétermination, Ryan & Deci, 2000) des étudiants à l’entrée en 1re année universitaire, selon deux contextes de formation (Faculté des Sciences et Institut Universitaire Technologique) et le lien avec la réussite académique. Trois profils motivationnels sont identifiés dont deux autonomes et contrôlés et un troisième dit amotivé qui se distribuent différemment selon les structures d’accueil. On observe également que la réussite en première année est associée à des sous-modalités distinctes de la motivation selon les structures. Ces résultats conduisent à une réflexion en terme de leviers motivationnels différenciés mais aussi en terme de projet de formation de l’étudiant et de transition lycée-université.This study aims to identify the motivational characteristics (theory of self-determination, Ryan & Deci, 2000) of students entering the first year of university, according to two training contexts (Faculty of Sciences and University Technological Institute) and the link with academic success. Three motivational profiles are identified, two of them are autonomous and controlled, and a third called amotivated. They are distributed differently according to the training structures. It is also observed that success at the first year is associated with distinct sub-modalities of motivation according to the structures. These results lead to some discussion in terms of differentiated motivational triggers but also in terms of student project and on the transition from high school to university