Heterocycles from wine: synthesis and biological evaluation of salidrosides

Wine is composed of a variety of tannins, of which a sub-class includes salidrosides, which are largely uninvestigated compounds. The first syntheses of galloylated salidrosides are reported in 7 steps from commercially available starting materials through a platform approach. The antimicrobial activity of the salidrosides against Escherichia coli strains is described

A New Look at an Old Cluster: The Membership, Rotation, and Magnetic Activity of Low-Mass Stars in the 1.3-Gyr-Old Open Cluster NGC 752

The nearby open cluster NGC 752 presents a rare opportunity to study stellar properties at ages >1 Gyr. However, constructing a membership catalog for it is challenging; most surveys have been limited to identifying its giants and dwarf members earlier than mid-K. We supplement past membership catalogs with candidates selected with updated photometric and proper-motion criteria, generating a list of 258 members, a >50% increase over previous catalogs. Using a Bayesian framework to fit MESA Isochrones & Stellar Tracks evolutionary models to literature photometry and the Tycho-Gaia Astrometric Solution data available for 59 cluster members, we infer the age of, and distance to, NGC 752: 1.34$\pm$0.06 Gyr and 438$_{-6}^{+8}$ pc. We also report the results of our optical monitoring of the cluster using the Palomar Transient Factory. We obtain rotation periods for 12 K and M cluster members, the first periods measured for such low-mass stars with a well-constrained age >1 Gyr. We compare these new periods to data from the younger clusters Praesepe and NGC 6811, and to a theoretical model for angular-momentum loss, to examine stellar spin down for low-mass stars over their first 1.3 Gyr. While on average NGC 752 stars are rotating more slowly than their younger counterparts, the difference is not significant. Finally, we use our spectroscopic observations to measure Halpha for cluster stars, finding that members earlier than $\approx$M2 are magnetically inactive, as expected at this age. Forthcoming Gaia data should solidify and extend the membership of NGC 752 to lower masses, thereby increasing its importance for studies of low-mass stars.Comment: Accepted to ApJ. This version 23 pages, 15 figures; on-line version will include 11 more figures as well as light curve data for the 12 rotators we identif

The Factory and the Beehive III: PTFEB132.707+19.810, a Low-Mass Eclipsing Binary in Praesepe Observed by PTF and K2

Theoretical models of stars constitute a fundamental bedrock upon which much of astrophysics is built, but large swaths of model parameter space remain uncalibrated by observations. The best calibrators are eclipsing binaries in clusters, allowing measurement of masses, radii, luminosities, and temperatures, for stars of known metallicity and age. We present the discovery and detailed characterization of PTFEB132.707+19.810, a P=6.0 day eclipsing binary in the Praesepe cluster ($\tau$~600--800 Myr; [Fe/H]=0.14$\pm$0.04). The system contains two late-type stars (SpT$_P$=M3.5$\pm$0.2; SpT$_S$=M4.3$\pm$0.7) with precise masses ($M_p=0.3953\pm0.0020$~$M_{\odot}$; $M_s=0.2098\pm0.0014$~$M_{\odot}$) and radii ($R_p=0.363\pm0.008$~$R_{\odot}$; $R_s=0.272\pm0.012$~$R_{\odot}$). Neither star meets the predictions of stellar evolutionary models. The primary has the expected radius, but is cooler and less luminous, while the secondary has the expected luminosity, but is cooler and substantially larger (by 20%). The system is not tidally locked or circularized. Exploiting a fortuitous 4:5 commensurability between $P_{orb}$ and $P_{rot,prim}$, we demonstrate that fitting errors from the unknown spot configuration only change the inferred radii by <1--2%. We also analyze subsets of data to test the robustness of radius measurements; the radius sum is more robust to systematic errors and preferable for model comparisons. We also test plausible changes in limb darkening, and find corresponding uncertainties of ~1%. Finally, we validate our pipeline using extant data for GU Boo, finding that our independent results match previous radii to within the mutual uncertainties (2--3%). We therefore suggest that the substantial discrepancies are astrophysical; since they are larger than for old field stars, they may be tied to the intermediate age of PTFEB132.707+19.810.Comment: Accepted to ApJ; 36 pages, 19 figures, 8 tables in two-column AASTEX6 forma

Enhancing Cardiac Rehabilitation With Stress Management Training

BACKGROUND: Cardiac rehabilitation (CR) is the standard of care for patients with coronary heart disease. Despite considerable epidemiological evidence that high stress is associated with worse health outcomes, stress management training (SMT) is not included routinely as a component of CR. METHODS AND RESULTS: One hundred fifty-one outpatients with coronary heart disease who were 36 to 84 years of age were randomized to 12 weeks of comprehensive CR or comprehensive CR combined with SMT (CR+SMT), with assessments of stress and coronary heart disease biomarkers obtained before and after treatment. A matched sample of CR-eligible patients who did not receive CR made up the no-CR comparison group. All participants were followed up for up to 5.3 years (median, 3.2 years) for clinical events. Patients randomized to CR+SMT exhibited greater reductions in composite stress levels compared with those randomized to CR alone (P=0.022), an effect that was driven primarily by improvements in anxiety, distress, and perceived stress. Both CR groups achieved significant, and comparable, improvements in coronary heart disease biomarkers. Participants in the CR+SMT group exhibited lower rates of clinical events compared with those in the CR-alone group (18% versus 33%; hazard ratio=0.49; 95% confidence interval, 0.25-0.95; P=0.035), and both CR groups had lower event rates compared with the no-CR group (47%; hazard ratio=0.44; 95% confidence interval, 0.27-0.71; P<0.001). CONCLUSIONS: CR enhanced by SMT produced significant reductions in stress and greater improvements in medical outcomes compared with standard CR. Our findings indicate that SMT may provide incremental benefit when combined with comprehensive CR and suggest that SMT should be incorporated routinely into CR. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00981253

From scientific models to companion modelling: engaging a dialogue with local actors in an Amazonian floodplain about biodiversity management at a territorial level

The Amazonian floodplain is among the most productive and diversified ecosystems in the world. The moving littoral enables a rapid nutrient recycling, explaining the large productivity and biodiversity of the system. Attracted by such favourable conditions for agricultural activities and fishing, populations have settled in the floodplains and developed complementary activities to cope with important variations in their environment, between the flood season and the dry season. However, in the past decades, the rhythm of these floodplains has changed, obliging the actors to deal with great uncertainty. Based on several years of hydrological and biogeochemical studies to understand the reasons of these environmental changes, the “life scientists” of our team invited the “social scientists” with the following question: Can the results about the dynamics of these floodplains help local populations better anticipate the future fluctuations of the river and adapt their activities to be less vulnerable to such change? To address this, we first chose to turn the perspective around: what were the preoccupations and strategies of local populations and what did they expect from scientists? The challenge was to enable the perceptions and knowledge of local populations to dialogue with scientific knowledge. Based on a Companion Modelling approach, we engaged a participatory process to collectively discuss the current situation and possible future scenarios. Using a role-playing game as an interface for this dialogue, we have progressively built a model to integrate both the knowledge of the local actors regarding their practices and possible environmental impacts and the knowledge of the scientists on environmental dynamics. This has obliged researchers to learn to work together and simplify their knowledge, and requires finding common points of interest with local populations, translating “biodiversity” into concrete issues that have a meaning for local actors. (Texte intégral