KIC 8462852 Faded throughout the Kepler Mission

KIC 8462852 is a superficially ordinary main sequence F star for which Kepler detected an unusual series of brief dimming events. We obtain accurate relative photometry of KIC 8462852 from the Kepler full-frame images, finding that the brightness of KIC 8462852 monotonically decreased over the four years it was observed by Kepler. Over the first ~1000 days KIC 8462852 faded approximately linearly at a rate of 0.341 ± 0.041% yr^(−1), for a total decline of 0.9%. KIC 8462852 then dimmed much more rapidly in the next ~200 days, with its flux dropping by more than 2%. For the final ~200 days of Kepler photometry the magnitude remained approximately constant, although the data are also consistent with the decline rate measured for the first 2.7 years. Of a sample of 193 nearby comparison stars and 355 stars with similar stellar parameters, none exhibit the rapid decline by >2% or the cumulative fading by 3% of KIC 8462852. Moreover, of these comparison stars, only one changes brightness as quickly as the 0.341% yr^(−1) measured for KIC 8462852 during the first three years of the Kepler mission. We examine whether the rapid decline could be caused by a cloud of transiting circumstellar material, finding that while such a cloud could evade detection in submillimeter observations, the transit ingress and duration cannot be explained by a simple cloud model. Moreover, this model cannot account for the observed longer-term dimming. No known or proposed stellar phenomena can fully explain all aspects of the observed light curve

Comparison of bacterial communities of tilapia fish from Cameroon and Vietnam using PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis)

Fishes in general and tilapia in particular are traded all over the world. However, it is difficult to find out their exact geographical location. One of the techniques used in the traceability of fish and its byproductsconsist in analysing in a global way the whole viable and non viable bacterial communities. For this purpose, the molecular technique employing the bacterial 16S DNA banding profiles generated by PCR-DGGE (polymerase chain reaction-Denaturing gradient gel electrophoresis) was used to evaluate the differences between the bacterial profiles of fishes from Vietnam (An Giang, south province) and those of Cameroon (Yagoua, Maga, Lagdo). The different PCR-DGGE 16S rDNA banding profiles obtained were analysed and results showed that there were specific bands for each geographical location though some bands common to Cameroon and Vietnam were observed. Thismethod could be used as a rapid analytical traceability tool for fish products and could be considered as a provider of a unique biological bar code

Influence of technological treatments on bacterial communities in tilapia (Oreochromis niloticus) as determined by 16S rDNA fingerprinting using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE)

Food quality and safety are major concern among consumers throughout the world in the context of globalization. Hence, the origin and the history of a food item are of prime interest when food quality is questioned. Precise determination of contamination source relies on the use of efficient and reliable methods. This study was carried out to assess the microbial ecology of fish upon technological treatments using 16S rDNA polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting. Samples of tilapia from Montpellier (South-east of France) and Yagoua (far north of Cameroon) were used for this purpose. The technological treatments applied on fillets were marinade, drying, smoking and deep-freezing. When the 16S rDNA profiles were analysed by multivariate analysis, distinct microbial communities were detected. The band profiles of fish bacteria after each treatment were different and specific. Technological treatments applied on fillets from Montpellier did not have an effect on the biological markers present on the fillets. These bands could be used as specific markers for this region. One of the treatments, the marinade applied on the samples of Yagoua induced the disappearance of some bands on the DGGE profile. In spite of treatment applied on samples, it is possible to recover the geographical origin by using DNA of the bacterial community in fish even if it was treated.Keywords: Traceability, tilapia, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), bacterial community, technological treatment

Diagnostic et caractérisation microbiologique des procédés artisanaux de fabrication de boissons et de concentrés d’Hibiscus sabdariffa L au Sénégal

L’Hibiscus sabdariffa L. est une plante très utilisée au Sénégal et presque dans toute l’Afrique de l’ouest. Les calices sont transformés en boisson, en concentré, en poudre, etc. par des petites et moyennes entreprises (PME) et des Groupements d’intérêt économiques (GIE). Les procédés de fabrications sont presque similaires avec quelques petites différences dans les entreprises. Cependant toutes les exigences des bonnes pratiques de fabrication et de suivi des lots ne sont pas systématiquement respectées comme la mise en place du plan HACCP (Hazard Analysis Critical Control Point) et un suivi sur le plan microbiologique des produits. Ainsi, l’objectif de ce travail est d’évaluer les diagrammes de fabrication de boissons et concentrés de bissap et de réaliser le contrôle microbiologique sur toutes les étapes du process dans 2 PME. Les visites effectuées sur les lieux de production ont permis de retracer tous les diagrammes de fabrication des différents produits. Et l’analyse microbiologique a été faite sur des échantillons prélevés au niveau de chaque étape du procédé. Les techniques classiques de la microbiologie alimentaire ont été utilisées pour la recherche de chaque germe selon les référentiels en vigueurs.Les résultats microbiologiques ont révélé une absence totale de bactéries pathogènes sur tout le procédé de transformation. Seule la présence de FMAT (Flore Mésophile Aérobie Totale), de levures et moisissures a été observée sur les échantillons. Cependant la présence d’un type de levure absente sur les matières premières a été notée sur toutes les étapes de la transformation. De plus le suivi microbiologique effectué sur un lot de production stocké à différentes températures (4, 10, 20, 30 et 37°C) pendant six mois a montré que le produit fini qui était salubre au départ présentait une certaine flore dont la quantité dépassait les valeurs seuils en vigueur. Le développement était plus remarqué sur les échantillons conservés à 4°C. Les résultats ont montré la présence d’une contamination croisée dont l’origine peut être diverse (personnel ; environnement, matériel). Pour étayer ce problème des études moléculaires de caractérisation permettant d’identifier les sources de contamination devront être menées de même que l’instauration d’un plan de suivi des bonnes pratiques d’hygiène et de fabrication.Mots-clés: procédé, microbiologie, boissons, concentrés d’Hibiscus sabdariffa. Diagnostic and microbiological characterization of artisanal processes of drinks and concentrates Hibiscus sabdariffa L SenegalHibiscus sabdariffa L. is a plant widely used in Senegal and almost throughout West Africa. Chalices are transformed into drink, concentrate, powder, etc. by small and medium enterprises (SMEs) and Groupings of economic interest grouping (EIG). The manufacturing processes are almost similar with few differences However, all the requirements needed in good manufacturing practices and lots monitoring are not always respected as the implementation of the HACCP plan (Hazard Analysis Critical Control Point) and the microbiologically follow of products. The objective of this study was to evaluate diagrams manufacture of beverages and concentrates bissap and perform microbiological control over all stages of the process in 2 SMEs. The visits to the places of production have allowed us to trace all the diagrams of manufacturing different products and microbiological analysis was performed on samples taken at each step of the process. Conventional techniques of food microbiology were used to research each seed according standard repository. Microbiological results revealed a complete absence of any pathogenic bacteria on the method of transformation. Only the presence of two floras FMAT, yeast and mold was observed on the samples analyzed. However, we noticed the presence of a type of yeast on all stages of processing but not commodities. Microbiological monitoring on a batch production is stored at various temperatures (4, 10, 20, 30 and 37°C) for six months shows that the finished product was wholesome initially showed some flora whose amount exceeds the threshold values in force. The development was noted on more samples stored at 4°C. These results showed the presence of cross-contamination whose origin is diverse (personnel environment and material). In support of this problem of molecular characterization studies to identify sources of contamination will be conducted as well as the establishment of a monitoring plan good hygiene and manufacturing practices.Keywords: process, microbiology, drinks, concentrates of Hibiscus sabdariffa

Stellar and Planetary Properties of K2 Campaign 1 Candidates and Validation of 17 Planets, Including a Planet Receiving Earth-like Insolation

The extended Kepler mission, K2, is now providing photometry of new fields every three months in a search for transiting planets. In a recent study, Foreman-Mackey and collaborators presented a list of 36 planet candidates orbiting 31 stars in K2 Campaign 1. In this contribution, we present stellar and planetary properties for all systems. We combine ground-based seeing-limited survey data and adaptive optics imaging with an automated transit analysis scheme to validate 21 candidates as planets, 17 for the first time, and identify 6 candidates as likely false positives. Of particular interest is K2-18 (EPIC 201912552), a bright (K=8.9) M2.8 dwarf hosting a 2.23 \pm 0.25 R_Earth planet with T_eq = 272 \pm 15 K and an orbital period of 33 days. We also present two new open-source software packages which enable this analysis. The first, isochrones, is a flexible tool for fitting theoretical stellar models to observational data to determine stellar properties using a nested sampling scheme to capture the multimodal nature of the posterior distributions of the physical parameters of stars that may plausibly be evolved. The second is vespa, a new general-purpose procedure to calculate false positive probabilities and statistically validate transiting exoplanets.Comment: 17 pages, 5 figures, 5 tables, accepted for publication in the Astrophysical Journal. Updated to closely reflect published version in ApJ (2015, 809, 25

Enrichissement en protéines du tourteau de coprah : sélection de champignons filamenteux en FMS = Protein enrichment of copra cake : selection of filamentous fungi in SSF

Les résultats ont montré que 11 souches sur 51 testées peuvent être retenues. Elles appartiennent aux espèces #Aspergillus sp., #Aspergillus niger, Penicillium italicum, Penicillium sp. et #Penicillium roquefortii$. Le rendement moyen d'enrichissement en protéines est de 20 %. Toutefois l'objectif n'est pas totalement atteint. Une optimisation des conditions de culture, en particulier, de la composition des milieux de culture, s'impose afin d'augmenter ces rendements protéiques et atteindre 50 %

KIC 8462852 Faded throughout the Kepler Mission

KIC 8462852 is a superficially ordinary main sequence F star for which Kepler detected an unusual series of brief dimming events. We obtain accurate relative photometry of KIC 8462852 from the Kepler full-frame images, finding that the brightness of KIC 8462852 monotonically decreased over the four years it was observed by Kepler. Over the first ~1000 days KIC 8462852 faded approximately linearly at a rate of 0.341 ± 0.041% yr^(−1), for a total decline of 0.9%. KIC 8462852 then dimmed much more rapidly in the next ~200 days, with its flux dropping by more than 2%. For the final ~200 days of Kepler photometry the magnitude remained approximately constant, although the data are also consistent with the decline rate measured for the first 2.7 years. Of a sample of 193 nearby comparison stars and 355 stars with similar stellar parameters, none exhibit the rapid decline by >2% or the cumulative fading by 3% of KIC 8462852. Moreover, of these comparison stars, only one changes brightness as quickly as the 0.341% yr^(−1) measured for KIC 8462852 during the first three years of the Kepler mission. We examine whether the rapid decline could be caused by a cloud of transiting circumstellar material, finding that while such a cloud could evade detection in submillimeter observations, the transit ingress and duration cannot be explained by a simple cloud model. Moreover, this model cannot account for the observed longer-term dimming. No known or proposed stellar phenomena can fully explain all aspects of the observed light curve

Optimization of cardiac cine in the rat on a clinical 1.5-T MR system

Object: the overall goal was to study cardiovascular function in small animals using a clinical 1.5-T MR scanner optimizing a fast gradient-echo cine sequence to obtain high spatial and temporal resolution. Materials and methods: normal rat hearts (n = 9) were imaged using a 1.5-T MR scanner with a spiral fast gradient-echo (fast field echo for Philips scanners) sequence, three Cartesian fast gradient-echo (turbo field echo for Philips scanners) sequences with different in-plane resolution, and with and without flow compensation and half-Fourier acquisition. The hearts of four rats were then excised and left-ventricle mass was weighed. Inter- and intra-observer variability analysis was performed for magnetic resonance imaging (MRI) measurements. Results: half-Fourier acquisition with flow compensation gave the best sequence in terms of image quality, spatial as well as temporal resolution, and suppression of flow artifact. Ejection fraction was 71 ± 4% with less than 5% inter- and intra-observer variability. A good correlation was found between MRI-calculated left-ventricular mass and wet weight. Conclusions: using optimized sequences on a clinical 1.5-T MR scanner can provide accurate quantification of cardiac function in small animals and can promote cardiovascular research on small animals at 1.5-