Open clusters are key tools to study the spatial distribution of abundances in the disk and their evolution with time. Using the first release of stellar parameters and abundances of the Gaia-ESO ...Survey, we analyse the chemical properties of stars in three old/intermediate-age open clusters, namely NGC 6705, NGC 4815, and Trumpler 20, all located in the inner part of the Galactic disk at Galactocentric radius R\(_{GC}\sim\)7 kpc, aiming at proving their homogeneity and at comparing them with the field population. We study the abundance ratios of elements belonging to two different nucleosynthetic channels: \(\alpha\)-elements and iron-peak elements. The main results can be summarised as follows: i) cluster members are chemically homogeneous within 3-\(\sigma\) in all analysed elements; ii) the three clusters have comparable El/Fe patters within \(\sim\)1-\(\sigma\), but they differ in their global metal content El/H, with NGC 4815 having the lowest metallicity. Their El/Fe ratios show differences and analogies with those of the field population, both in the solar neighbourhood and in the bulge/inner disk; iii) comparing the abundance ratios with the results of two chemical evolution models and with field star abundance distributions, we find that the abundance ratios of Mg, Ni, Ca in NGC 6705 might require an inner birthplace, implying a subsequent variation of its R\(_{GC}\) during its lifetime, consistent with previous orbit determination. The full dataset of the Gaia-ESO Survey will be a superlative tool to constrain the chemical evolution of our Galaxy by disentangling different formation and evolution scenarios.
Context. This study has been developed in the framework of the computational simulations executed for the preparation of the ESA Gaia astrometric mission. Aims. We focus on describing the objects and ...characteristics that Gaia will potentially observe without taking into consideration instrumental effects (detection efficiency, observing errors). Methods. The theoretical Universe Model prepared for the Gaia simulation has been statistically analyzed at a given time. Ingredients of the model are described, giving most attention to the stellar content, the double and multiple stars, and variability. Results. In this simulation the errors have not been included yet. Hence we estimate the number of objects and their theoretical photometric, astrometric and spectroscopic characteristics in the case that they are perfectly detected. We show that Gaia will be able to potentially observe 1.1 billion of stars (single or part of multiple star systems) of which about 2% are variable stars, 3% have one or two exoplanets. At the extragalactic level, observations will be potentially composed by several millions of galaxies, half million to 1 million of quasars and about 50,000 supernovas that will occur during the 5 years of mission. The simulated catalogue will be made publicly available by the DPAC on the Gaia portal of the ESA web site http://www.rssd.esa.int/gaia/.
Milky Way open clusters are very diverse in terms of age, chemical composition, and kinematic properties. Intermediate-age and old open clusters are less common, and it is even harder to find them ...inside the solar Galactocentric radius, due to the high mortality rate and strong extinction inside this region. NGC 6802 is one of the inner disk open clusters (IOCs) observed by the \(Gaia\)-ESO survey (GES). This cluster is an important target for calibrating the abundances derived in the survey due to the kinematic and chemical homogeneity of the members in open clusters. Using the measurements from \(Gaia\)-ESO internal data release 4 (iDR4), we identify 95 main-sequence dwarfs as cluster members from the GIRAFFE target list, and eight giants as cluster members from the UVES target list. The dwarf cluster members have a median radial velocity of \(13.6\pm1.9\) km s\(^{-1}\), while the giant cluster members have a median radial velocity of \(12.0\pm0.9\) km s\(^{-1}\) and a median Fe/H of \(0.10\pm0.02\) dex. The color-magnitude diagram of these cluster members suggests an age of \(0.9\pm0.1\) Gyr, with \((m-M)_0=11.4\) and \(E(B-V)=0.86\). We perform the first detailed chemical abundance analysis of NGC 6802, including 27 elemental species. To gain a more general picture about IOCs, the measurements of NGC 6802 are compared with those of other IOCs previously studied by GES, that is, NGC 4815, Trumpler 20, NGC 6705, and Berkeley 81. NGC 6802 shows similar C, N, Na, and Al abundances as other IOCs. These elements are compared with nucleosynthetic models as a function of cluster turn-off mass. The \(\alpha\), iron-peak, and neutron-capture elements are also explored in a self-consistent way.
Carotenoids are the most common pigments in nature and are synthesized by all photosynthetic organisms and fungi. Carotenoids are considered key molecules for life. Light capture, photosynthesis ...photoprotection, excess light dissipation and quenching of singlet oxygen are among key biological functions of carotenoids relevant for life on earth. Biological properties of carotenoids allow for a wide range of commercial applications. Indeed, recent interest in the carotenoids has been mainly for their nutraceutical properties. A large number of scientific studies have confirmed the benefits of carotenoids to health and their use for this purpose is growing rapidly. In addition, carotenoids have traditionally been used in food and animal feed for their color properties. Carotenoids are also known to improve consumer perception of quality; an example is the addition of carotenoids to fish feed to impart color to farmed salmon.
Background: Gastric cancer is the second highest cause of cancer deaths worldwide.;
Apart from Japan and Korea where screening programs are implemented, most;
gastric cancer patients worldwide are ...diagnosed at an advanced stage because of;
limited knowledge and experience of endoscopists. An internet-based e-learning system to teach detection of early gastric cancer using standard endoscopy has been;
developed and this study evaluated its effectiveness. Methods: The study was designed;
as a randomized controlled trial. Participants worldwide signed a consent;
form before first undertaking a pre-test via the internet, after which they were;
randomly allocated to the e-learning and non-e-learning groups. Pre-adjustment;
strata were the pre-test score, experience of endoscopy, being a nurse endoscopist;
or a medical practitioner, and medical institution and country. Only the participants;
in the e-learning group were allowed to access the e-learning system, which consisted;
of video lectures on basic knowledge and self-exercise tests to accumulate;
experience. A post-test in both groups was conducted 2 months after the pre-test.;
The pre-determined primary endpoint was the difference in the rate of improvement;
of the test result (post-test score/pre-test score) between groups. After;
completion of the post-test, the e-learning system was opened for all participants.;
Results: Among the 515 endoscopists from 35 countries assessed for eligibility, 322;
participants who met the study’s inclusion criteria completed the pre-test and were;
enrolled: 166 were allocated to the e-learning group and 166 to the non-e-learning.;
Of these, 151 participants in the e-learning group and 144 in the non-e-learning;
group completed the post-test, and were included in the analysis. The mean rate of;
improvement (standard deviation) of the test result in the e-learning and non-elearning;
groups was 1.24 (0.26) and. 1.00 (0.16), respectively (P!0.001, Student’s ttest).;
Conclusion: This global study clearly demonstrated the efficacy of an e-learning;
system to improve knowledge and experience on endoscopic detection of early;
gastric cancer. Its effectiveness will be further evaluated in a study of improvements;
in the rate of early gastric cancer detection by all participants in actual clinical;
practice (UMIN: R000012039).
Trabajo presentado en el DDW2015 Digestive Disease Week (DDW 2015), desarrolado del 16 al 19 de Mayo, 2015 en la ciudad de Washington DC, EE.UU
We report the peculiar chemical abundance patterns of 11 atypical Milky Way (MW) field red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). These atypical ...giants exhibit strong Al and N enhancements accompanied by C and Mg depletions, strikingly similar to those observed in the so-called second-generation (SG) stars of globular clusters (GCs). Remarkably, we find low Mg abundances (Mg/Fe. < 0.0) together with strong Al and N overabundances in the majority (5/7) of the metal-rich (Fe/H greater than or similar to-1.0) sample stars, which is at odds with actual observations of SG stars in Galactic GCs of similar metallicities. This chemical pattern is unique and unprecedented among MW stars, posing urgent questions about its origin. These atypical stars could be former SG stars of dissolved GCs formed with intrinsically lower abundances of Mg and enriched Al (subsequently self-polluted by massive AGB stars) or the result of exotic binary systems. We speculate that the stars Mg-deficiency as well as the orbital properties suggest that they could have an extragalactic origin. This discovery should guide future dedicated spectroscopic searches of atypical stellar chemical patterns in our Galaxy, a fundamental step forward to understanding the Galactic formation and evolution.
