C II abundances in early-type stars: solution to a notorious non-LTE problem

We address a long-standing discrepancy between non-LTE analyses of the prominent C II 4267 and 6578/82 A multiplets in early-type stars. A comprehensive non-LTE model atom of C II is constructed based on critically selected atomic data. This model atom is used for an abundance study of six apparently slow-rotating main-sequence and giant early B-type stars. High-resolution and high-S/N spectra allow us to derive highly consistent abundances not only from the classical features but also from up to 18 further C II lines in the visual - including two so far unreported emission features equally well reproduced in non-LTE. These results require the stellar atmospheric parameters to be determined with care. A homogeneous (slightly) sub-solar present-day carbon abundance from young stars in the solar vicinity (in associations and in the field) of log C/H +12= 8.29+/-0.03 is indicated.Comment: 8 pages, 5 figure

The Projected Rotational Velocity Distribution of a Sample of OB stars from a Calibration based on Synthetic He I lines

We derive projected rotational velocities (vsini) for a sample of 156 Galactic OB star members of 35 clusters, HII regions, and associations. The HeI lines at $\lambda\lambda$4026, 4388, and 4471A were analyzed in order to define a calibration of the synthetic HeI full-widths at half maximum versus stellar vsini. A grid of synthetic spectra of HeI line profiles was calculated in non-LTE using an extensive helium model atom and updated atomic data. The vsini's for all stars were derived using the He I FWHM calibrations but also, for those target stars with relatively sharp lines, vsini values were obtained from best fit synthetic spectra of up to 40 lines of CII, NII, OII, AlIII, MgII, SiIII, and SIII. This calibration is a useful and efficient tool for estimating the projected rotational velocities of O9-B5 main-sequence stars. The distribution of vsini for an unbiased sample of early B stars in the unbound association Cep OB2 is consistent with the distribution reported elsewhere for other unbound associations.Comment: Accepted for publication in The Astronomical Journa

A dinucleotide deletion in the ankyrin promoter alters gene expression, transcription initiation and TFIID complex formation in hereditary spherocytosis

Ankyrin defects are the most common cause of hereditary spherocytosis (HS). In some HS patients, mutations in the ankyrin promoter have been hypothesized to lead to decreased ankyrin mRNA synthesis. The ankyrin erythroid promoter is a member of the most common class of mammalian promoters which lack conserved TATA, initiator or other promoter cis elements and have high G+C content, functional Sp1 binding sites and multiple transcription initiation sites. We identified a novel ankyrin gene promoter mutation, a TG deletion adjacent to a transcription initiation site, in a patient with ankyrin-linked HS and analyzed its effects on ankyrin expression. In vitro, the mutant promoter directed decreased levels of gene expression, altered transcription initiation site utilization and exhibited defective binding of TATA-binding protein (TBP) and TFIID complex formation. In a transgenic mouse model, the mutant ankyrin promoter led to abnormalities in gene expression, including decreased expression of a reporter gene and altered transcription initiation site utilization. These data indicate that the mutation alters ankyrin gene transcription and contributes to the HS phenotype by decreasing ankyrin gene synthesis via disruption of TFIID complex interactions with the ankyrin core promoter. These studies support the model that in promoters that lack conserved cis elements, the TFIID complex directs preinitiation complex formation at specific sites in core promoter DNA and provide the first evidence that disruption of TBP binding and TFIID complex formation in this type of promoter leads to alterations in start site utilization, decreased gene expression and a disease phenotype in viv

New insight into BRST anomalies in superstring theory

Based on the extended BRST formalism of Batalin, Fradkin and Vilkovisky, we perform a general algebraic analysis of the BRST anomalies in superstring theory of Neveu-Schwarz-Ramond. Consistency conditions on the BRST anomalies are completely solved. The genuine super-Virasoro anomaly is identified with the essentially unique solution to the consistency condition without any reference to a particular gauge for the 2D supergravity fields. In a configuration space where metric and gravitino fields are properly constructed, general form of the super-Weyl anomaly is obtained from the super-Virasoro anomaly as its descendant. We give a novel local action of super-Liouville type, which plays a role of Wess-Zumino-Witten term shifting the super-Virasoro anomaly into the super-Weyl anomaly. These results reveal a hierarchial relationship in the BRST anoamlies.Comment: 29 pages, PHYZZ

The ARAUCARIA project: Grid-Based Quantitative Spectroscopic Study of Massive Blue Stars in NGC55

The quantitative study of the physical properties and chemical abundances of large samples of massive blue stars at different metallicities is a powerful tool to understand the nature and evolution of these objects. Their analysis beyond the Milky Way is challenging, nonetheless it is doable and the best way to investigate their behavior in different environments. Fulfilling this task in an objective way requires the implementation of automatic analysis techniques that can perform the analyses systematically, minimizing at the same time any possible bias. As part of the ARAUCARIA project we carry out the first quantitative spectroscopic analysis of a sample of 12 B-type supergiants in the galaxy NGC55 at 1.94 Mpc away. By applying the methodology developed in this work, we derive their stellar parameters, chemical abundances and provide a characterization of the present-day metallicity of their host galaxy. Based on the characteristics of the stellar atmosphere/line formation code FASTWIND, we designed and created a grid of models for the analysis of massive blue supergiant stars. Along with this new grid, we implemented a spectral analysis algorithm. Both tools were specially developed to perform fully consistent quantitative spectroscopic analyses of low spectral resolution of B-type supergiants in a fast and objective way. We present the main characteristics of our FASTWIND model grid and perform a number of tests to investigate the reliability of our methodology. The automatic tool is applied afterward to a sample of 12 B-type supergiant stars in NGC55, deriving the stellar parameters and abundances. The results indicate that our stars are part of a young population evolving towards a red supergiant phase. The derived chemical composition hints to an average metallicity similar to the one of the Large Magellanic Cloud, with no indication of a spatial trend across the galaxy.Comment: 19 pages, 12 figures and 9 tables. Accpeted for publication in A&

Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC

While the tracking detectors of the ATLAS and CMS experiments have shown excellent performance in Run 1 of LHC data taking, and are expected to continue to do so during LHC operation at design luminosity, both experiments will have to exchange their tracking systems when the LHC is upgraded to the high-luminosity LHC (HL-LHC) around the year 2024. The new tracking systems need to operate in an environment in which both the hit densities and the radiation damage will be about an order of magnitude higher than today. In addition, the new trackers need to contribute to the first level trigger in order to maintain a high data-taking efficiency for the interesting processes. Novel detector technologies have to be developed to meet these very challenging goals. The German groups active in the upgrades of the ATLAS and CMS tracking systems have formed a collaborative "Project on Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC" (PETTL), which was supported by the Helmholtz Alliance "Physics at the Terascale" during the years 2013 and 2014. The aim of the project was to share experience and to work together on key areas of mutual interest during the R&D phase of these upgrades. The project concentrated on five areas, namely exchange of experience, radiation hardness of silicon sensors, low mass system design, automated precision assembly procedures, and irradiations. This report summarizes the main achievements

Chemical composition of B-type supergiants in the OB8, OB10, OB48, OB78 associations of M31

Absolute and differential chemical abundances are presented for the largest group of massive stars in M31 studied to date. These results were derived from intermediate resolution spectra of seven B-type supergiants, lying within four OB associations covering a galactocentric distance of 5 - 12 kpc. The results are mainly based on an LTE analysis, and we additionally present a full non-LTE, unified model atmosphere analysis of one star (OB78-277) to demonstrate the reliability of the differential LTE technique. A comparison of the stellar oxygen abundance with that of previous nebular results shows that there is an offset of between ~0.15 - 0.4 dex between the two methods which is critically dependent on the empirical calibration adopted for the R23 parameter with [O/H]. However within the typical errors of the stellar and nebular analyses (and given the strength of dependence of the nebular results on the calibration used) the oxygen abundances determined in each method are fairly consistent. We determine the radial oxygen abundance gradient from these stars, and do not detect any systematic gradient across this galactocentric range. We find that the inner regions of M31 are not, as previously thought, very 'metal rich'. Our abundances of C, N, O, Mg, Si, Al, S and Fe in the M31 supergiants are very similar to those of massive stars in the solar neighbourhood.Comment: 15 pages, 9 figures and 9 tables. Submitted to A&A April 200

Abundance analysis of prime B-type targets for asteroseismology I. Nitrogen excess in slowly-rotating beta Cephei stars

We present the results of a detailed NLTE abundance study of nine beta Cephei stars, all of them being prime targets for theoretical modelling: gamma Peg, delta Cet, nu Eri, beta CMa, xi1 CMa, V836 Cen, V2052 Oph, beta Cep and DD (12) Lac. The following chemical elements are considered: He, C, N, O, Mg, Al, Si, S and Fe. Our abundance analysis is based on a large number of time-resolved, high-resolution optical spectra covering in most cases the entire oscillation cycle of the stars. Nitrogen is found to be enhanced by up to 0.6 dex in four stars, three of which have severe constraints on their equatorial rotational velocity, \Omega R, from seismic or line-profile variation studies: beta Cep (\Omega R~26 km/s), V2052 Oph (\Omega R~56 km/s), delta Cet (\Omega R < 28 km/s) and xi1 CMa (\Omega R sin i < 10 km/s). The existence of core-processed material at the surface of such largely unevolved, slowly-rotating objects is not predicted by current evolutionary models including rotation. We draw attention to the fact that three stars in this subsample have a detected magnetic field and briefly discuss recent theoretical work pointing to the occurrence of diffusion effects in beta Cephei stars possibly capable of altering the nitrogen surface abundance. On the other hand, the abundances of all the other chemical elements considered are, within the errors, indistinguishable from the values found for OB dwarfs in the solar neighbourhood. Despite the mild nitrogen excess observed in some objects, we thus find no evidence for a significantly higher photospheric metal content in the studied beta Cephei stars compared to non-pulsating B-type stars of similar characteristics.Comment: Accepted for publication in A&A, 21 pages, 7 figure

Chapter X: The Tour de France: a success story in spite of competitive imbalance and doping

International audienceThe chapter goes as follows. In the first section it is demonstrated how the Tour de France is a high quality product. This is a result from its accurate design, its management, its economic model and its finance structure, both in comparison to other mega-sporting events and with reference to tournament theory. It is not easy to assess the competitive balance in the Tour de France since, as was demonstrated in chapter 10, it is at the same time an individual and a team sport contest. After reviewing some results published in literature so far, a new metrics for evaluating competitive balanced in the Tour de France is presented in section 2. Finally, the Tour de France cannot ignore doping as a potential threat to fan attendance and TV viewing. We therefore discuss the issue of doping and a new procedure to deal with doping in section 3

Anxiety, Stress, Depression, and Patients’ Responses to Periodontal Treatment: Periodontists’ Knowledge and Professional Behavior

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142063/1/jper0064.pd