ALBERT

Description: M-dwarf stars--hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun--are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized planets in great numbers: the average number of M-dwarf planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per star. The nearest such planets known to transit their star are 39 parsecs away, too distant for detailed follow-up observations to measure the planetary masses or to study their atmospheres. Here we report observations of GJ 1132b, a planet with a size of 1.2 Earth radii that is transiting a small star 12 parsecs away. Our Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like bulk composition, similar to the compositions of the six known exoplanets with masses less than six times that of the Earth and precisely measured densities. Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Berta-Thompson, Zachory K -- Irwin, Jonathan -- Charbonneau, David -- Newton, Elisabeth R -- Dittmann, Jason A -- Astudillo-Defru, Nicola -- Bonfils, Xavier -- Gillon, Michael -- Jehin, Emmanuel -- Stark, Antony A -- Stalder, Brian -- Bouchy, Francois -- Delfosse, Xavier -- Forveille, Thierry -- Lovis, Christophe -- Mayor, Michel -- Neves, Vasco -- Pepe, Francesco -- Santos, Nuno C -- Udry, Stephane -- Wunsche, Anael -- England -- Nature. 2015 Nov 12;527(7577):204-7. doi: 10.1038/nature15762.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. ; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA. ; Observatoire de Geneve, Universite de Geneve, 51 chemin des Maillettes, 1290 Sauverny, Switzerland. ; Universite Grenoble Alpes, IPAG, F-38000 Grenoble, France. ; CNRS, IPAG, F-38000 Grenoble, France. ; Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout 17, Batiment B5C, 4000 Liege, Belgium. ; Institute for Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA. ; Laboratoire d'Astrophysique de Marseille, UMR 6110 CNRS, Universite de Provence, 38 rue Frederic Joliot-Curie, 13388, Marseille Cedex 13, France. ; Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, Rio Grande do Norte, Brazil. ; Instituto de Astrofisica e Ciencias do Espaco, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal. ; Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26560298" target="_blank"〉PubMed〈/a〉

Description: We performed a uniform and detailed abundance analysis of 12 refractory elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn, and V) for a sample of 257 G- and K-type evolved stars from the CORALIE planet search programme. To date, only one of these stars is known to harbour a planetary companion. We aimed to characterize this large sample of evolved stars in terms of chemical abundances and kinematics, thus setting a solid base for further analysis of planetary properties around giant stars. This sample, being homogeneously analysed, can be used as a comparison sample for other planet-related studies, as well as for different type of studies related to stellar and Galaxy astrophysics. The abundances of the chemical elements were determined using an local thermodynamic equilibrium (LTE) abundance analysis relative to the Sun, with the spectral synthesis code moog and a grid of Kurucz ATLAS9 atmospheres. To separate the Galactic stellar populations, both a purely kinematical approach and a chemical method were applied. We confirm the overabundance of Na in giant stars compared to the field FGK dwarfs. This enhancement might have a stellar evolutionary character, but departures from LTE may also produce a similar enhancement. Our chemical separation of stellar populations also suggests a ‘gap’ in metallicity between the thick-disc and high-α metal-rich stars, as previously observed in dwarfs sample from HARPS. The present sample, as most of the giant star samples, also suffers from the B – V colour cut-off, which excludes low-log g stars with high metallicities, and high-log g star with low [Fe/H]. For future studies of planet occurrence dependence on stellar metallicity around these evolved stars, we suggest to use a subsample of stars in a ‘cut-rectangle’ in the log g –[Fe/H] diagram to overcome the aforementioned issue.

Description: Pulp therapy is the last resort for preserving deciduous teeth. However, the genotoxic and cytotoxic effects of many products used in this therapy are not well established. The aim of this study was to use the micronucleus test on bone marrow from mice to evaluate the genotoxic and cytotoxic effects of four filling pastes: zinc oxide, calcium hydroxide P.A., mineral trioxide aggregate and an iodoform paste (iodoform + camphorated + paramonochlorophenol + rifamycin + prednisolone). Male Swiss mice were divided into 4 groups of 10 animals, each exposed to one of the pastes, and were subdivided according to the dilutions tested: 1/10, 1/50, 1/500 and 1/1000 administered intraperitoneally (0.1ml/10g of weight). Cyclophosphamide was the positive control. The negative controls were dimethylsulfoxide and buffered saline solution. Five animals were killed 24h and five 48h after the treatment. The material was processed in accordance with Schmid (1976) and micronuclei were counted in 1000 polychromatic erythrocytes (PCE), under an optical microscope in a blinded test. Cytotoxicity was evaluated using the PCE/normochromatic erythrocyte (NCE) ratio in 200 erythrocytes. The micronucleus analysis results were evaluated using the conditional test for comparing proportions in situations of rare events. Analysis of variance and Tukey’s test were used to evaluate the PCE/NCE ratio. There was significantly greater occurrence of micronuclei in the animals treated with iodoform paste at all the dilutions tested, at both sacrifice times. Greater occurrence of micronuclei was observed among the animals treated with zinc oxide and sacrificed 48h after the treatment, at the dilutions 1:50; 1:500 and 1:1000. Calcium hydroxide P.A. and mineral trioxide aggregate did not present any genotoxic or cytotoxic effects. The genotoxicity and cytotoxicity of zinc oxide and iodoform paste revealed here constitute an initial step towards their contraindication, but additional studies will be necessary in order to securely establish the risks involved in their use.

Description: The statistical validation of transiting exoplanets proved to be an efficient technique to secure the nature of small exoplanet signals which cannot be established by purely spectroscopic means. However, the spectroscopic diagnoses are providing us with useful constraints on the presence of blended stellar contaminants. In this paper, we present how a contaminating star affects the measurements of the various spectroscopic diagnoses as a function of the parameters of the target and contaminating stars using the model implemented into the pastis planet-validation software. We find particular cases for which a blend might produce a large radial velocity signal but no bisector variation. It might also produce a bisector variation anticorrelated with the radial velocity one, as in the case of stellar spots. In those cases, the full width at half-maximum variation provides complementary constraints. These results can be used to constrain blend scenarios for transiting planet candidates or radial velocity planets. We review all the spectroscopic diagnoses reported in the literature so far, especially the ones to monitor the line asymmetry. We estimate their uncertainty and compare their sensitivity to blends. Based on that, we recommend the use of BiGauss which is the most sensitive diagnosis to monitor line-profile asymmetry. In this paper, we also investigate the sensitivity of the radial velocities to constrain blend scenarios and develop a formalism to estimate the level of dilution of a blended signal. Finally, we apply our blend model to re-analyse the spectroscopic diagnoses of HD 16702, an unresolved face-on binary which exhibits bisector variations.

Description: Understanding the interconnections of microbial pathogenicity phenomena, such as biofilm formation, quorum sensing and antimicrobial resistance, is a tremendous open challenge for biomedical research. Progress made by wet-lab researchers and bioinformaticians in understanding the underlying regulatory phenomena has been significant, with converging evidence from multiple high-throughput technologies. Notably, network reconstructions are already of considerable size and quality, tackling both intracellular regulation and signal mediation in microbial infection. Therefore, it stands to reason that in silico investigations would play a more active part in this research. Drug target identification and drug repurposing could take much advantage of the ability to simulate pathogen regulatory systems, host–pathogen interactions and pathogen cross-talking. Here, we review the bioinformatics resources and tools available for the study of the gram-negative bacterium Pseudomonas aeruginosa , the gram-positive bacterium Staphylococcus aureus and the fungal species Candida albicans . The choice of these three microorganisms fits the rationale of the review converging into pathogens of great clinical importance, which thrive in biofilm consortia and manifest growing antimicrobial resistance.

Description: We present the results of an optical photometry and high-resolution spectroscopy campaign for a modest sample of X-ray selected stars in the Chamaeleon and Rho Ophiuchus star-forming regions. With R ~ 50 000 optical spectra, we establish kinematic membership of the parent association and confirm stellar youth for each star in our sample. With the acquisition of new standardized BVIc photometry, in concert with near-infrared data from the literature, we derive age and mass from stellar positions in model-dependent Hertzsprung–Russell diagrams. We compare isochronal ages derived using colour-dependent extinction values finding that, within error bars, ages are the same irrespective of whether E ( B – V ), E ( V – Ic ), E ( J – H ) or E ( H – K ) is used to establish extinction, although model ages tend to be marginally younger for redder E colour values. For Cham I and Cham members, we derive ages of 5–6 Myr, whereas our three Cha candidates are more consistent with a 25 Myr post-T Tauri star population. In Rho Ophiuchus, most stars in our sample have isochronal ages 〈10 Myr. Five objects show evidence of strong infrared excess ( Av 〉 5) in the Two Micron All Sky Survey colour–colour diagram, however in terms of Hα emission, all stars except RXJ1625.6–2613 are consistent with being weak-lined T-Tauri stars. Spectral energy distributions (SEDs) over the range ~=4000 Å 〈 〈 1000 μm, show that only one Chamaeleon star (RXJ1112.7 –7637) and three Rho Ophiuchus stars (ROXR1 13, RXJ1625.6–2613 & RXJ1627.1–2419) reveal substantial departures from a bare photosphere.

Description: The old and metal-rich open cluster NGC 6253 was observed with the Fibre Large Array Multi Element Spectrograph (FLAMES) multi-object spectrograph during an extensive radial velocity campaign monitoring 317 stars with a median of 15 epochs per object. All the targeted stars are located along the upper main sequence of the cluster between 14.8 〈 V 〈 16.5. Fifty nine stars are confirmed cluster members both by radial velocities and proper motions and do not show evidence of variability. We detected 45 variable stars among which 25 belong to NGC 6253. We were able to derive an orbital solution for four cluster members (and for two field stars) yielding minimum masses in between ~90 M J and ~460 M J and periods between 3 and 220 d. Simulations demonstrated that this survey was sensitive to objects down to 30 M J at 10 days orbital periods with a detection efficiency equal to 50 per cent. On the basis of these results we concluded that the observed frequency of binaries down to the hydrogen burning limit and up to 20 d orbital period is around (1.5 ± 1.3) per cent in NGC 6253. The overall observed frequency of binaries around the sample of cluster stars is (13 ± 3) per cent. The median radial velocity precision achieved by the GIRAFFE spectrograph in this magnitude range was around ~240 m s – 1 (~180 m s – 1 for UVES). Based on a limited follow-up analysis of seven stars in our sample with the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph we determined that a precision of 35 m s – 1 can be reached in this magnitude range, offering the possibility to further extend the variability analysis into the substellar domain. Prospects are even more favourable once considering the upcoming ESPRESSO spectrograph at VLT.

Description: Herbicides cause environmental concerns because they are toxic and accumulate in the environment, food products and water supplies. There is a need to develop safe, efficient and economical methods to remove t...