A collision-induced satellite in the Lyman Beta profile due to H-H collisions

We present a theoretical profile of the Lyman Beta line of atomic hydrogen perturbed by collisions with neutral hydrogen atoms and protons. We use a general unified theory in which the electric dipole moment varies during a collision. A collision-induced satellite appears on Lyman Beta, correlated to the B''\barB 1Sigma+u - X 1Sigma+g asymptotically forbidden transition of H_2. As a consequence, the appearance of the line wing between Lyman Alpha and Lyman Beta is shown to be sensitive to the relative abundance of hydrogen ions and neutral atoms, and thereby to provide a temperature diagnostic for stellar atmospheres and laboratory plasmas.Comment: 8 pages, 4 figures, acc.f.publ.European Physical Journal

Dichroic Masers due to Radiation Anisotropy and the Influence of the Hanle Effect on the Circumstellar SiO Polarization

The theory of the generation and transfer of polarized radiation, mainly developed for interpreting solar spectropolarimetric observations, allows to reconsider, in a more rigorous and elegant way, a physical mechanism that has been suggested some years ago to interpret the high degree of polarization often observed in astronomical masers. This mechanism, for which the name of 'dichroic maser' is proposed, can operate when a low density molecular cloud is illuminated by an anisotropic source of radiation (like for instance a nearby star). Here we investigate completely unsaturated masers and show that selective stimulated emission processes are capable of producing highly polarized maser radiation in a non-magnetic environment. The polarization of the maser radiation is linear and is directed tangentially to a ring equidistant to the central star. We show that the Hanle effect due to the presence of a magnetic field can produce a rotation (from the tangential direction) of the polarization by more that 45 degrees for some selected combinations of the strength, inclination and azimuth of the magnetic field vector. However, these very same conditions produce a drastic inhibition of the maser effect. The rotations of about 90 degrees observed in SiO masers in the evolved stars TX Cam by Kemball & Diamond (1997) and IRC+10011 by Desmurs et al (2000) may then be explainedby a local modification of the anisotropy of the radiation field, being transformed from mainly radial to mainly tangential.Comment: Accepted for publication on Ap

The Learning by the Creation of Event: Theatrical Approach, Interactive, Co-Operative and Individualizing Pedagogy of Project (The Case of the Artistic Carnival of the PPP in the ISET of Gabès)

Abstract In the framework of the valorization of the pedagogy of project via the development of the learning by the event, we organized a day dedicated to the fair of the Professional Project personalized by a theatrical production of outputs animated by the students accompanied. This experience based on the adoption of the active pedagogy generated interesting results in terms of satisfaction, self-confidence, positive emotions, exceeding itself, vitality, pleasure and self-realization. An event, which constitutes a clinical case of active pedagogy, worthy of the reinvestments in the future. This document will attempt to synthesize this experience in describing, student the inputs to the catalysis of the participation and by analyzing the main results generated by this event

Quasi-molecular lines in Lyman wings of cool DA white dwarfs; Application to FUSE observations of G231-40

We present new theoretical calculations of the total line profiles of Lyman alpha and Lyman beta which include perturbations by both neutral hydrogen AND protons and all possible quasi-molecular states of H_2 and H_2^+. They are used to improve theoretical modeling of synthetic spectra for cool DA white dwarfs. We compare them with FUSE observation of G231-40. The appearance of the line wings between Lyman alpha and Lyman beta is shown to be sensitive to the relative abundance of hydrogen ions and neutral atoms, and thereby to provide a temperature diagnostic for stellar atmospheres and laboratory plasmas.Comment: 6 pages, 4 figures, accepted for publication in Astronomy and Astrophysic

Effect of foliar Boron application on growth, phenology, yield and oil quality of olive trees (cv. Arbequina) conducted under a high density planting system

1 .pdf (3 Tabls.) copia del póster original presentado por los autores en el Simposio Internacional.Foliar boron fertilization is commonly used in intensive olive orchards without knowledge about the efficiency of this fertilization on olive production.Peer reviewe

Total transition probability and spontaneous radiative dissociation of B, C, B′ and D states of molecular hydrogen

The total radiative transition probabilities of rovibronic levels of B, C, B′ and D states of molecular hydrogen are calculated with emphasis on the dissociation fraction and the kinetic energy released in the continuum radiation process. The mixing percentages of B, C, B′ and D adiabatic states are also given. The data are calculated with the detailed transition probabilities obtained by Abgrall et al. (1993, 1994). We have included, in the present analysis, results obtained by using a recent ab initio transition moment for D - X which comprises a larger range of internuclear distances. The related data on individual transition probabilities may be obtained on request.


Distribution of microplankton in relation to environmental variables during summer stratification in the Gulf of Hammamet, Tunisia

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Infrared transitions of SiO (Drira+, 1997)

VizieR On-line Data Catalog: J/A+A/319/720. Originally published in: 1997A&A...319..720DSpectroscopic properties of SiO have been calculated from highly correlated wave functions. The computed dipole moments for v=0-3 agree well with the experimental data of Raymonda et al. (1970, J. Chem. Phys. 52, 3458). By comparing the present results with previous theoretical works, we estimate that the resulting line strengths should be the most accurate to date. The Einstein coefficients for the fundamental and the first overtone (v<=40, J<=100) are larger than the currently used values of Tipping & Chackerian (1981, J. Mol. Spectr. 88, 352), and should be tested in models of stellar atmospheres. (1 data file)

Molecular and structural characterizations of lipases from Chlorella by functional genomics

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