On differential rotation and overshooting in solar-like stars

This is the author accepted manuscript. The final version is available from American Astronomical Society via the DOI in this record.We seek to characterize how the change of global rotation rate influences the overall dynamics and large scale flows arising in the convective envelopes of stars covering stellar spectral types from early G to late K. We do so through numerical simulations with the ASH code, where we consider stellar convective envelopes coupled to a radiative interior with various global properties. As solar-like stars spin down over the course of their main sequence evolution, such change must have a direct impact on their dynamics and rotation state. We indeed find that three main states of rotation may exist for a given star: anti-solar-like (fast poles, slow equator), solar-like (fast equator, slow poles), or a cylindrical rotation profile. Under increasingly strict rotational constraints, the latter profile can further evolve into a Jupiter-like profile, with alternating prograde and retrograde zonal jets. We have further assessed how far the convection and meridional flows overshoot into the radiative zone and investigated the morphology of the established tachocline. Using simple mixing length arguments, we are able to construct a scaling of the fluid Rossby number $R_{of} = \tilde{\omega}/2\Omega_* \sim \tilde{v}/2\Omega_* R_*$, which we calibrate based on our 3-D ASH simulations. We can use this scaling to map the behavior of differential rotation versus the global parameters of stellar mass and rotation rate. Finally, we isolate a region on this map ($R_{of} \gtrsim 1.5-2$) where we posit that stars with an anti-solar differential rotation may exist in order to encourage observers to hunt for such targets.We acknowledge funding by ERC STARS2 207430 grant, ANR Blanc Toupies SIMI5-6 020 01, INSU/PNST, CNES SolarOrbiter, PLATO and GOLF grants, FP7 SpaceInn 312844 grant, and NASA grants NNX11AJ36G, NNX13AG18G and NNX16AC92G. K. C. Augustson is funded through the ERC SPIRE 647383 grant. A. Strugarek acknowledges support from the Canadian Institute of Theoretical Astrophysics (National Fellow), from Canadas Natural Sciences and Engineering Research Council and from CNES postdoctoral fellowship

Chromatin and epigenetics: current biophysical views

Recent advances in high-throughput sequencing experiments and their theoretical descriptions have determined fast dynamics of the "chromatin and epigenetics" field, with new concepts appearing at high rate. This field includes but is not limited to the study of DNA-protein-RNA interactions, chromatin packing properties at different scales, regulation of gene expression and protein trafficking in the cell nucleus, binding site search in the crowded chromatin environment and modulation of physical interactions by covalent chemical modifications of the binding partners. The current special issue does not pretend for the full coverage of the field, but it rather aims to capture its development and provide a snapshot of the most recent concepts and approaches. Eighteen open-access articles comprising this issue provide a delicate balance between current theoretical and experimental biophysical approaches to uncover chromatin structure and understand epigenetic regulation, allowing free flow of new ideas and preliminary results

Evaluation of long-term efficacy and acceptability of indapamide SR in elderly hypertensive patients

Objective: To assess the long-term antihypertensive efficacy and acceptability of indapamide SR 1,5 mg in elderly hypertensive patients ((greater-than or equal to) 65 years). Study design: Open, 12-month, follow-up study of 444 patients, treated with indapamide SR, who were responders and/or achieved target BP levels following a 3-month, randomised, controlled, double-blind short-term comparison of indapamide SR versus hydrochlorothiazide 25 mg and amlodipine 5 mg. Results: The long-term decrease in systolic blood pressure (SBP)/diastolic blood pressure (DBP) after 12 months follow-up with indapamide SR was -24.0/-13.1 mmHg from baseline (MO). The percentage of patients that achieved target BP levels (DBP < 95 mmHg, SBP (less-than or equal to) 160 mmHg) was 80.1% [84.3% for isolated systolic hypertension (ISH) subgroup], and the response rate (BP < 140/90 mmHg or decrease in supine diastolic BP (greater-than or equal to) 10 mmHg or in supine systolic BP (greater-than or equal to) 20 mmHg) 81.5%. Blood pressure (BP) remained stable throughout the 12 months follow-up period (M3-M15), whatever the previous treatment received during the 3-month, double-blind period (MO-M3). Clinical and biological acceptability was good. A low occurrence of withdrawals (7.2%), was reported. Conclusion: Over the course of the long-term, 12-month follow-up study, indapamide SR was shown to be an effective and well tolerated antihypertensive therapy, even after a switch from amlodipine or hydrochlorothiazide, in patients aged 65 years-80 years with systolo-diastolic hypertension (SDH) or ISH. (copyright) 2005 LIBRAPHARM LIMITED

Origine et dynamique des populations de colza hors des champs

National audienceWithin the context of the release of transgenic oilseed rape into the environment, feral oilseed rape populations present on road side verges are likely to induce management problems to take over transgenes and reduce their spread in space and time. Especially, in the case of herbicide tolerant oilseed rape, weeding problems and the persistence of transgenic oilseed rape after the end of their cultivation are expected. The risk assessment associated with the take over of any transgene is conditioned by a good knowledge of the origin and the dynamics of these feral populations. Our study, which combines observations, modelling and experiments at the level of a small agricultural area, shows that (1) oilseed rape seeds can persist at least 8 years after cultivation by secondary dormancy breakdown and/or self-recruitment and (2) farming machinery plays a role in both the spatial distribution and the seed dispersal of feral populations. Results of the model designed for an isolated feral population highlight the effect of mowing and chemical spraying in road side verges and the effect of the seed bank, even under demographic and environmental stochasticity, on the persistence of feral oilseed rape populations.Dans le cadre de l'introduction de colzas transgéniques dans l'environnement, les populations de colza présentes en bordure de champs (populations hors-champs) sont susceptibles de poser un certain nombre de problèmes de gestion en cas d'échappement du transgène : problème de désherbage dans le cas de colzas résistants aux herbicides, rôle de relais du transgène et persistance de colzas transgéniques après un arrêt éventuel de leur mise en culture. L'estimation de ces risques associés à l'échappement et au maintien du transgène est conditionnée par une bonne connaissance de l'origine et la dynamique de ces populations. Notre étude alliant observations à l'échelle d'une petite région agricole, modélisation et expérimentations, met en évidence une persistance de colzas au moins 8 années après leur mise en culture par levée de dormance secondaire et/ou par autorecrutement, ainsi que le rôle des engins de récolte dans la répartition spatiale des populations et donc dans la dispersion des graines. Les résultats d'un modèle réalisé pour l'instant à l'échelle d'une population isolée mettent en évidence le rôle de la fauche et des traitements chimiques des bordures sur le maintien des populations hors-champs et le rôle de la banque de graines dans un contexte de stochasticité démographique et environnementale

Changements d'echelles de flux de gènes. Analyse spatio-temporelle en vue de l'aide à la décision

International audienc

Analyse rétrospective sur le devenir de variétés de colza 0 et 00 dans l'environnement

National audienc

Consistent and Transferable Force Fields for Statistical Copolymer Systems at the Mesoscale

The statistical trajectory matching (STM) method was applied successfully to derive coarse grain (CG) models for bulk properties of homopolymers. The extension of the methodology for building CG models for statistical copolymer systems is much more challenging. We present here the strategy for developing CG models for styrene–butadiene–rubber, and we compare the quality of the resulting CG force fields on the structure and thermodynamics at different chemical compositions. The CG models are used through the use of a genuine mesoscopic method called the dissipative particle dynamics method and compared to high-resolution molecular dynamics simulations. We conclude that the STM method is able to produce coarse-grained potentials that are transferable in composition by using only a few reference systems. Additionally, this methodology can be applied on any copolymer system