University of Geneva

About: University of Geneva is a education organization based out in Geneva, Switzerland. It is known for research contribution in the topics: Population & Planet. The organization has 26887 authors who have published 65265 publications receiving 2931373 citations. The organization is also known as: Geneva University & Universite de Geneve.

The Newick utilities

Abstract: Summary: We present a suite of Unix shell programs for processing any number of phylogenetic trees of any size. They perform frequently-used tree operations without requiring user interaction. They also allow tree drawing as scalable vector graphics (SVG), suitable for high-quality presentations and further editing, and as ASCII graphics for command-line inspection. As an example we include an implementation of bootscanning, a procedure for finding recombination breakpoints in viral genomes. Availability: C source code, Python bindings and executables for various platforms are available from http://cegg.unige.ch/newick_utils. The distribution includes a manual and example data. The package is distributed under the BSD License. Contact: thomas.junier@unige.ch

Spin-orbit angle measurements for six southern transiting planets New insights into the dynamical origins of hot Jupiters

Abstract: Context. Several competing scenarios for planetary-system formation and evolution seek to explain how hot Jupiters came to be so close to their parent stars. Most planetary parameters evolve with time, making it hard to distinguish between models. The obliquity of an orbit with respect to the stellar rotation axis is thought to be more stable than other parameters such as eccentricity. Most planets, to date, appear aligned with the stellar rotation axis; the few misaligned planets so far detected are massive (\textgreater2 M-J). Aims. Our goal is to measure the degree of alignment between planetary orbits and stellar spin axes, to search for potential correlations with eccentricity or other planetary parameters and to measure long term radial velocity variability indicating the presence of other bodies in the system. Methods. For transiting planets, the Rossiter-McLaughlin effect allows the measurement of the sky-projected angle beta between the stellar rotation axis and a planet's orbital axis. Using the HARPS spectrograph, we observed the Rossiter-McLaughlin effect for six transiting hot Jupiters found by the WASP consortium. We combine these with long term radial velocity measurements obtained with CORALIE. We used a combined analysis of photometry and radial velocities, fitting model parameters with the Markov Chain Monte Carlo method. After obtaining beta we attempt to statistically determine the stribution of the real spin-orbit angle psi. Results. We found that three of our targets have beta above 90 degrees: WASP-2b: beta = 153 degrees(+11)(-15), WASP-15b: beta = 139.6 degrees(+5.2)(-4.3) and WASP-17b: beta = 148.5 degrees(+5.1)(-4.2); the other three (WASP-4b, WASP-5b and WASP-18b) have angles compatible with 0 degrees. We find no dependence between the misaligned angle and planet mass nor with any other planetary parameter. All six orbits are close to circular, with only one firm detection of eccentricity e = 0.00848(-0.00095)(+0.00085) in WASP-18b. No long-term radial acceleration was detected for any of the targets. Combining all previous 20 measurements of beta and our six and transforming them into a distribution of psi we find that between about 45 and 85% of hot Jupiters have psi \textgreater 30 degrees. Conclusions. Most hot Jupiters are misaligned, with a large variety of spin-orbit angles. We find observations and predictions using the Kozai mechanism match well. If these observational facts are confirmed in the future, we may then conclude that most hot Jupiters are formed from a dynamical and tidal origin without the necessity to use type I or II migration. At present, standard disc migration cannot explain the observations without invoking at least another additional process.

Optimal learning in optimal contexts: The role of self-determination in education

Abstract: In English : This literature review provides an overview of education studies that have been guided by self-determination theory (SDT). First, the authors examine studies that have assessed motivation based on SDT. Second, the authors detail research that has focussed on the linkages between motivation types and students' behavioural, affective, and cognitive outcomes. Third, the authors present studies on how learning contexts (parents, teachers) contribute to students' motivational resources. The authors conclude that the motivation types proposed by SDT are important for understanding how students thrive and succeed at school. The authors also highlight the significant role played by teachers and parents in the development of student motivation. The authors conclude with a summary of the benefits of self-motivation for learning and offer some recommendations for the field. (PsycINFO Database Record (c) 2016 APA, all rights reserved) Resume en francais (langue de l'article en anglais) : Le present article procure une vue d'ensemble des etudes sur l'education qui ont ete guidees par la theorie de l'autodetermination. En premier lieu, nous examinons les etudes qui ont evalue la motivation fondee sur la theorie de l'autodetermination. Nous expliquons ensuite la recherche portant sur les liens existant entre les types de motivation et les resultats des etudiants en matiere de comportement et de composantes affectives et cognitives. Nous presentons aussi les etudes sur les contextes d'apprentissage (parents, enseignants) qui contribuent aux ressources motivationnelles des etudiants. Nous en deduisons que les types de motivation proposes par la theorie de l'autodetermination permettent de comprendre les elements qui permettent aux etudiants de se demarquer et de reussir en milieu scolaire. Nous mettons aussi en relief le role important que jouent les enseignants et les parents dans le developpement de la motivation de l'eudiant. En conclusion, nous presentons un resume des bienfaits de l'automotivation dans le cadre de l'apprentissage et offrons quelques recommandations pertinentes au domaine en question. (PsycINFO Database Record (c) 2016 APA, all rights reserved)

Centrosome duplication in mammalian somatic cells requires E2F and Cdk2-cyclin A.

Abstract: Centrosome duplication is a key requirement for bipolar spindle formation and correct segregation of chromosomes during cell division. In a manner highly reminiscent of DNA replication, the centrosome must be duplicated once, and only once, in each cell cycle. How centrosome duplication is regulated and coordinated with other cell-cycle functions remains poorly understood. Here, we have established a centrosome duplication assay using mammalian somatic cells. We show that centrosome duplication requires the activation of E2F transcription factors and Cdk2–cyclin A activity.

Patterns of \(Cis\) Regulatory Variation in Diverse Human Populations

Abstract: The genetic basis of gene expression variation has long been studied with the aim to understand the landscape of regulatory variants, but also more recently to assist in the interpretation and elucidation of disease signals. To date, many studies have looked in specific tissues and population-based samples, but there has been limited assessment of the degree of inter-population variability in regulatory variation. We analyzed genome-wide gene expression in lymphoblastoid cell lines from a total of 726 individuals from 8 global populations from the HapMap3 project and correlated gene expression levels with HapMap3 SNPs located in cis to the genes. We describe the influence of ancestry on gene expression levels within and between these diverse human populations and uncover a non-negligible impact on global patterns of gene expression. We further dissect the specific functional pathways differentiated between populations. We also identify 5,691 expression quantitative trait loci (eQTLs) after controlling for both non-genetic factors and population admixture and observe that half of the cis-eQTLs are replicated in one or more of the populations. We highlight patterns of eQTL-sharing between populations, which are partially determined by population genetic relatedness, and discover significant sharing of eQTL effects between Asians, European-admixed, and African subpopulations. Specifically, we observe that both the effect size and the direction of effect for eQTLs are highly conserved across populations. We observe an increasing proximity of eQTLs toward the transcription start site as sharing of eQTLs among populations increases, highlighting that variants close to TSS have stronger effects and therefore are more likely to be detected across a wider panel of populations. Together these results offer a unique picture and resource of the degree of differentiation among human populations in functional regulatory variation and provide an estimate for the transferability of complex trait variants across populations.