Theoretical seismic properties of pre-main sequence gamma Doradus pulsators

Context. gamma Doradus (gamma Dor) are late A and F-type stars pulsating with high order gravity modes (g-modes). The existence of different evolutionary phases crossing the gamma Dor instability strip raises the question of the existence of pre-main sequence (PMS) gamma Dor stars. Aims. We intend to study the differences between the asteroseismic behaviour of PMS and main sequence (MS) gamma Dor pulsators as it is predicted by the current theory of stellar evolution and stability. Methods. We explore the adiabatic and non-adiabatic properties of high order g-modes in a grid of PMS and MS models covering the mass range 1.2 Msun < Mstar < 2.5 Msun. Results. We derive the theoretical instability strip (IS) for the PMS gamma Dor pulsators. This IS covers the same effective temperature range as the MS gamma Dor one. Nevertheless, the frequency domain of unstable modes in PMS models with a fully radiative core is larger than in MS models, even if they present the same number of unstable modes. Moreover, the differences between MS and PMS internal structures are reflected on the average values of the period spacing as well as on the dependence of the period spacing on the radial order of the modes, opening the window to the determination of the evolutionary phase of gamma Dor stars from their pulsation spectra.Comment: 9 pages, 17 figures, accepted for publication in A&

Hybrid gamma Doradus/delta Scuti Stars: Comparison Between Observations and Theory

Gamma Doradus are F-type stars pulsating with high order g-modes. Their instability strip (IS) overlaps the red edge of the delta Scuti one. This observation has led to search for objects in this region of the HR diagram showing p and g-modes simultaneously. The existence of such hybrid pulsators has recently been confirmed (Handler 2009) and the number of candidates is increasing (Matthews 2007). From a theoretical point of view, non-adiabatic computations including a time-dependent treatment of convection (TDC) predict the existence of gamma Dor/delta Sct hybrid pulsators (Dupret et al. 2004; Grigahcene et al. 2006). Our aim is to confront the properties of the observed hybrid candidates with the theoretical predictions from non-adiabatic computations of non-radial pulsations including the convection-pulsation interaction.Comment: 3 pages, 3 figures, Poster at "Stellar Pulsation: challenges for theory and observation", Santa Fe, June 200

The synthesis of TiO2 thin film by Chemical Bath Deposition (CBD) method

Titanium oxide (TiO2) films have several advantages for applications in solar cells and very commonly used as a photo-catalyst for degradation of environmental pollutants. In this study, TiO2 films were synthesized using, a simple, less expensive, low temperature and convenient for large area deposition method, a chemical bath deposition (CBD) and their structural and optical properties were examined at various calcinations temperatures. The X-ray diffraction (XRD) technique shows the presence of the picks characteristic of anatase phase after annealing our films at 500°C, 600°C and rutile phase appears after heat treatment at 700°C. The surface morphology of the deposited films was characterized by the FEG scanning electronic microscopy (FEGSEM) and atomic force microscopy (AFM). Energy dispersive X-ray spectroscopy (EDS) analysis was used to determine the chemical composition of the prepared films. The UV-Vis-NIR spectroscopy shows that the film exhibits a transmission around 60%. The indirect band gap of the deposited films was between 2.88 and 3.22 eV

KIC 10080943: a binary star with two γ Doradus/δ Scuti hybrid pulsators. Analysis of the g modes

We use 4 yr of Kepler photometry to study the non-eclipsing spectroscopic binary KIC 10080943. We find both components to be γ Doradus/δ Scuti hybrids, which pulsate in both p and g modes. We present an analysis of the g modes, which is complicated by the fact that the two sets of l = 1 modes partially overlap in the frequency spectrum. Nevertheless, it is possible to disentangle them by identifying rotationally split doublets from one component and triplets from the other. The identification is helped by the presence of additive combina- tion frequencies in the spectrum that involve the doublets but not the triplets. The rotational splittings of the multiplets imply core rotation periods of about 11 and 7 d in the two stars. One of the stars also shows evidence of l = 2 modes

NUMERICAL SIMULATION OF PHOTOCURRENT IN A SOLAR CELL BASED AMORPHOUS SILICON

We propose in this work, a method of simulation based on the resolution of the equations of continuities for homostructures of silicon-based solar, and used a method of calculation the photocurrent delivered by the silicon solar cell applying the equations of continuities and the currents by analogy to the phenomena of loads transport according to the model of an homojunction n-a-Si:H/p-a-Si:H. We used Matlab software to simulate and optimize the layers thicknesses to achieve the maximum photocurrent generated under AM1.5 solar spectrum. The optimization of donor layer thickness shows clearly that the best results are obtained with the finest structures.  We worked out a numerical model based on the resolution of the equations of continuities who gave the results in good agreement with literature and which allowed, moreover a better control of the performances of the cells based on silicon, for their improvement

Lymphome t/nk primitif du larynx : localisation inhabituelle de lymphome extranodal

Nous rapportons un cas de lymphome extranodal T/Nk primitif du larynx. il s’agit d’un patient âgé de 22 ans qui s’était présenté pour une dysphonie chronique associée à une dyspnée inspiratoire. une chimiothérapie protocole SMiLE avec radiothérapie ont été institués avec obtention d’une rémission complète. Huit mois plus tard, le patient présentait une récidive de la tumeur avec un oedème palpébral et une obstruction du canal lacrymonasal. L’évolution a été fatale suite à une aspergillose invasive en cours de chimiothérapie.Mots clés : lymphome, larynx.A rare case of primary laryngeal T/Nk- cell lymphoma, nasal type is reported. The patient was 22-year old male who presented with dysphonia, dyspnea. Chemotherapy protocol SMiLE and radiotherapy were instituted with complete remission of the tumor. Eight months afterward, he presented with tumor recurrence, palpebral edema, obstruction of the lacrymonasal duct. He died within few days with invasive aspergillosis while he was receiving chemotherapy SMiLE regimen.Keyswords : lymphoma, larynx

Pig immune response to general stimulus and to porcine reproductive and respiratory syndrome virus infection: a meta-analysis approach

BACKGROUND: The availability of gene expression data that corresponds to pig immune response challenges provides compelling material for the understanding of the host immune system. Meta-analysis offers the opportunity to confirm and expand our knowledge by combining and studying at one time a vast set of independent studies creating large datasets with increased statistical power. In this study, we performed two meta-analyses of porcine transcriptomic data: i) scrutinized the global immune response to different challenges, and ii) determined the specific response to Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection. To gain an in-depth knowledge of the pig response to PRRSV infection, we used an original approach comparing and eliminating the common genes from both meta-analyses in order to identify genes and pathways specifically involved in the PRRSV immune response. The software Pointillist was used to cope with the highly disparate data, circumventing the biases generated by the specific responses linked to single studies. Next, we used the Ingenuity Pathways Analysis (IPA) software to survey the canonical pathways, biological functions and transcription factors found to be significantly involved in the pig immune response. We used 779 chips corresponding to 29 datasets for the pig global immune response and 279 chips obtained from 6 datasets for the pig response to PRRSV infection, respectively. RESULTS: The pig global immune response analysis showed interconnected canonical pathways involved in the regulation of translation and mitochondrial energy metabolism. Biological functions revealed in this meta-analysis were centred around translation regulation, which included protein synthesis, RNA-post transcriptional gene expression and cellular growth and proliferation. Furthermore, the oxidative phosphorylation and mitochondria dysfunctions, associated with stress signalling, were highly regulated. Transcription factors such as MYCN, MYC and NFE2L2 were found in this analysis to be potentially involved in the regulation of the immune response. The host specific response to PRRSV infection engendered the activation of well-defined canonical pathways in response to pathogen challenge such as TREM1, toll-like receptor and hyper-cytokinemia/ hyper-chemokinemia signalling. Furthermore, this analysis brought forth the central role of the crosstalk between innate and adaptive immune response and the regulation of anti-inflammatory response. The most significant transcription factor potentially involved in this analysis was HMGB1, which is required for the innate recognition of viral nucleic acids. Other transcription factors like interferon regulatory factors IRF1, IRF3, IRF5 and IRF8 were also involved in the pig specific response to PRRSV infection. CONCLUSIONS: This work reveals key genes, canonical pathways and biological functions involved in the pig global immune response to diverse challenges, including PRRSV infection. The powerful statistical approach led us to consolidate previous findings as well as to gain new insights into the pig immune response either to common stimuli or specifically to PRRSV infection

gamma Doradus stars in the COROT exoplanets fields: first inspection

We present here preliminary results concerning 32 stars identified as main gamma Doradus candidates by the COROT Variable Classifier (CVC) among the 4 first fields of the exoplanet CCDs.Comment: To appear in "Stellar Pulsation: Challenges for Theory and Observation", AI

The Liquid Argon in A Testbeam (LArIAT) experiment

The LArIAT liquid argon time projection chamber, placed in a tertiary beam of charged particles at the Fermilab Test Beam Facility, has collected large samples of pions, muons, electrons, protons, and kaons in the momentum range 0∼30-0140 MeV/c. This paper describes the main aspects of the detector and beamline, and also reports on calibrations performed for the detector and beamline components

Calorimetry for low-energy electrons using charge and light in liquid argon

Precise calorimetric reconstruction of 5-50 MeV electrons in liquid argon time projection chambers (LArTPCs) will enable the study of astrophysical neutrinos in DUNE and could enhance the physics reach of oscillation analyses. Liquid argon scintillation light has the potential to improve energy reconstruction for low-energy electrons over charge-based measurements alone. Here we demonstrate light-augmented calorimetry for low-energy electrons in a single-phase LArTPC using a sample of Michel electrons from decays of stopping cosmic muons in the LArIAT experiment at Fermilab. Michel electron energy spectra are reconstructed using both a traditional charge-based approach as well as a more holistic approach that incorporates both charge and light. A maximum-likelihood fitter, using LArIAT\u27s well-tuned simulation, is developed for combining these quantities to achieve optimal energy resolution. A sample of isolated electrons is simulated to better determine the energy resolution expected for astrophysical electron-neutrino charged-current interaction final states. In LArIAT, which has very low wire noise and an average light yield of 18 pe/MeV, an energy resolution of σ/E≃9.3%/E 1.3% is achieved. Samples are then generated with varying wire noise levels and light yields to gauge the impact of light-augmented calorimetry in larger LArTPCs. At a charge-readout signal-to-noise of S/N≃30, for example, the energy resolution for electrons below 40 MeV is improved by ≈10%, ≈20%, and ≈40% over charge-only calorimetry for average light yields of 10 pe/MeV, 20 pe/MeV, and 100 pe/MeV, respectively