The rotational shear layer inside the early red-giant star KIC 4448777

We present the asteroseismic study of the early red-giant star KIC 4448777, complementing and integrating a previous work (Di Mauro et al. 2016), aimed at characterizing the dynamics of its interior by analyzing the overall set of data collected by the {\it Kepler} satellite during the four years of its first nominal mission. We adopted the Bayesian inference code DIAMOND (Corsaro \& De Ridder 2014) for the peak bagging analysis and asteroseismic splitting inversion methods to derive the internal rotational profile of the star. The detection of new splittings of mixed modes, more concentrated in the very inner part of the helium core, allowed us to reconstruct the angular velocity profile deeper into the interior of the star and to disentangle the details better than in Paper I: the helium core rotates almost rigidly about 6 times faster than the convective envelope, while part of the hydrogen shell seems to rotate at a constant velocity about 1.15 times lower than the He core. In particular, we studied the internal shear layer between the fast-rotating radiative interior and the slow convective zone and we found that it lies partially inside the hydrogen shell above $r \simeq 0.05R$ and extends across the core-envelope boundary. Finally, we theoretically explored the possibility for the future to sound the convective envelope in the red-giant stars and we concluded that the inversion of a set of splittings with only low-harmonic degree $l\leq 3$, even supposing a very large number of modes, will not allow to resolve the rotational profile of this region in detail.Comment: accepted for publication on Ap

First observation of Cherenkov rings with a large area CsI-TGEM-based RICH prototype

We have built a RICH detector prototype consisting of a liquid C6F14 radiator and six triple Thick Gaseous Electron Multipliers (TGEMs), each of them having an active area of 10x10 cm2. One triple TGEM has been placed behind the liquid radiator in order to detect the beam particles, whereas the other five have been positioned around the central one at a distance to collect the Cherenkov photons. The upstream electrode of each of the TGEM stacks has been coated with a 0.4 micron thick CsI layer. In this paper, we will present the results from a series of laboratory tests with this prototype carried out using UV light, 6 keV photons from 55Fe and electrons from 90Sr as well as recent results of tests with a beam of charged pions where for the first time Cherenkov Ring images have been successfully recorded with TGEM photodetectors. The achieved results prove the feasibility of building a large area Cherenkov detector consisting of a matrix of TGEMs.Comment: Presented at the International Conference NDIP-11, Lyon,July201

Breaking the core-envelope symmetry in p-mode pulsating stars

It has been shown that there is a potential ambiguity in the asteroseismic determination of the location of internal structures in a pulsating star. We show how, in the case of high-order non-radial acoustic modes, it is possible to remove this ambiguity by considering modes of different degree. To support our conclusions we have investigated the seismic signatures of sharp density variations in the structure of quasi-homogeneous models.Comment: 3 pages, 3 figures, accepted for publication in Astronomy and Astrophysic

Progress in Developing Hybrid RPCs: GEM-like Detectors with Resistive Electrodes

We have recently developed an innovative detector of photons and charged particles: a GEM-like gaseous amplification structure with resistive electrodes instead of commonly used metallic ones. This novel detector combines the best property of GEMs- the capability to operate in a cascaded mode and in poorly quenched gases - and of RPC: the protection against sparks. In this paper will shortly review our latest achievements in this direction, however the main focus will be given on a new advanced design that allows to build large area detectors manufactured by a screen printing technology. The proposed detector, depending on the applications, can operate either in a GEM mode (electron multiplications through holes only) or as a hybrid RPC with simultaneous amplifications in the drift region and in the holes. The possible applications of this new detector will be discussed

The intrinsic topological information of the wild-type and of up-promoter mutations of the Saccharomyces cerevisiae alcohol dehydrogenase II regulatory region.

A 569-base pair fragment encompassing the upstream regulatory region, the RNA initiation sites, and the initial part of the coding region of the Saccharomyces cerevisiae alcohol dehydrogenase II gene has been analyzed for the presence of sites which undergo conformational modification under torsional stress. Fine mapping of P1 and S1 endonuclease-sensitive sites was obtained on single topoisomers produced by in vitro ligation. It was shown that the upstream activator sequence, the TATA sequence, a region directly upstream to the RNA initiation sites, and several positions in the first segment of the transcribed region change conformation as a function of the applied torsional stress in a precisely coordinate fashion. The superhelical density optima for this coordinate modifications have been determined. Analysis of the conformational changes of the promoter sequence in several naturally occurring (Young, E. T., Williamson, V. M., Taguchi, A., Smith, M., Sledziewski, L., Russel, D., Osterman, J., Denis, C., Cox, D., and Beier, D., (1982) in Genetic Engineering of Microorganisms for Chemicals (Hollander, A., De Moss, R. D., Kaplan, S., Konisky, J., Savage, D., and Wolle, R. S., eds) pp. 335-361, Plenum Publishing Corp., New York) up-promoter constitutive mutants was performed. This analysis has shown that the conformation of functionally relevant sites changes as a function of sequence mutations that have taken place elsewhere; this shows that the conformational behavior of the whole promoter region is linked and suggests transmission in cis of topological effects in RNA polymerase II promoters

R&D results on a CsI-TTGEM based photodetector

The very high momentum particle identification detector proposed for the ALICE upgrade is a focusing RICH using a C4F10 gaseous radiator. For the detection of Cherenkov photons, one of the options currently under investigation is to use a CsI coated Triple-Thick-GEM (CsI-TTGEM) with metallic or resistive electrodes. We will present results from the laboratory studies as well as preliminary results of beam tests of a RICH detector prototype consisting of a CaF2 radiator coupled to a 10x10 cm2 CsI-TTGEM equipped with a pad readout and GASSIPLEX-based front-end electronics. With such a prototype the detection of Cherenkov photons simultaneously with minimum ionizing particles has been achieved for the first time in a stable operation mode

Efficiency of microsatellite markers in assisted selection for resistance to soybean cyst nematode (race 3).

Four microsatellite sequences were tested in soybean DNA from cultivars and segregating genotypes. Three of them were close to the resistance locus rhg 1 on molecular linkage group G (Satt 309, Sat_168, Sat_163) and one was close to Rhg4 locus on group A2 (Sat_162). Progenies previously classified as cyst nematode (SNC) resistant and others with unknown reaction were tested, using the resistant cultivars Liderança, and Renascença and the susceptibles 'Cristalina' and 'OCEPAR-4' as control. The best primer for resistance to SCN was Sat_162. Twenty segregant progenies tested with Sat_162 presented a 150 bp band for homozygous resistant genotypes and 200 bp for susceptible ones, and both for the heterozigous genotypes. Previous studies have shown that this microsatellite marker is efficient to select genotypes carrying Peking-derivative resistance. 'Peking' takes part in the in the genealogy of all segregant progenies evaluated in this study. Thus, the obtained results showed that Sat_162 distinguished resistant and susceptible soybean genotypes to SCN, race 3

Study of GEM-like detectors with resistive electrodes for RICH applications

We have developed prototypes of GEM-like detectors with resistive electrodes to be used as RICH photodetectors equipped with CsI photocathodes. The main advantages of these detectors are their intrinsic spark protection and possibility to operate at high gain (~10E5) in many gases including poorly quenched ones, allowing for the adoption of windowless configurations in which the radiator gas is also used in the chamber. Results of systematic studies of the resistive GEMs combined with CsI photocathodes are presented: its quantum efficiency, rate characteristics, long-term stability, etc. On the basis of the obtained results, we believe that the new detector will be a promising candidate for upgrading the ALICE RICH detectorComment: Presented at the International Workshop RICH-2007, Trieste, Italy, October 200

Formamide as the main building block in the origin of nucleic acids

The simplest molecules grouping the four most common elements of the universe H,C,O and N (with the exception of the biologically inert He) are isocyanate HNCO and formamide H2NCOH. Reasons for the availability of formamide on prebiotic Earth are presented. We review evidence showing that formamide in the presence of largely available catalysts and by moderate heating yields the complete set of nucleic bases necessary for the formation of nucleic acids. Formamide also favours the formation of acyclonucleosides and the phosphorylation and trans-phosphorylation of nucleosides, thus providing a plausible chemical frame for the passage from a simple one-carbon compound to nucleic polymers. Physico-chemical conditions exist in which formamide favours the stability of the phosphoester bonds in nucleic polymers relative to that of the same bonds in monomers. Starting from a formamide-laden environment subject only to the laws of chemistry, a hypothesis is outlined sketching the passage towards an aqueous world in which Darwinian rules apply