Evapotranspiration en zone semi-aride de deux couverts végétaux (gazon, blé) obtenue par plusieurs méthodes : 2. Méthodes neutroniques et tensiométriques

International audienc

Influence of oxygen deficiency on optical and dielectric properties of La0.75Ba0.10Sr0.15FeO2.875-δ compounds

Using the conventional sol-gel process, the series of non-stoichiometric oxygen lanthanum ferrites with the formula 0.750.100.152.875 ― (δ=0.00, 0.125 and 0.25) were prepared. X-ray diffraction analysis confirmed the formation of the orthorhombic structure with Pnma space group. In the present work, we confirm the potential of 0.750.100.15 2.875 ― (δ=0.00, 0.125 and 0.25) as an efficient dielectric material. All samples show high absorbance in the visible region with wavelength above 300 nm. The optical band gaps are found to increase from 3.25 to 4.1 with increasing oxygen vacancy concentration. The dielectric constant, dielectric loss and loss factor were carried out as a function of oxygen vacancy concentration and frequency (102 -106 Hz) at room temperature. The variation of dielectric constant with frequency indicates dispersive behavior and giant dielectric response (more than 104 ) at low frequencies for compounds deficient in oxygen. Such value of makes ′ these samples an interesting material to be used in applications namely the reduction of electronic components size. To summarize, incorporating vacancy oxygen enhances the dielectric properties. Thus, the interesting dielectric constant and weak loss strengthen the use for potential applications.publishe

COMPETING MECHANISMS OF MOLECULAR HYDROGEN FORMATION IN CONDITIONS RELEVANT TO THE INTERSTELLAR MEDIUM

International audienceThe most efficient mechanism of the formation of molecular hydrogen in the current universe is by association of hydrogen atoms on the surface of interstellar dust grains. The details of the processes of its formation and release from the grain are of great importance in the physical and chemical evolution of the space environmentswhere it takes place. Themain puzzle is still the fate of the 4.5 eV released in H2 formation and whether it goes into internal energy (rovibrational excitation), translational kinetic energy, or heating of the grain. The modality of the release of this energy affects the dynamics of the ISM and its evolution toward star formation.We present results of the detection of the rovibrational states of the just-formed H2 as it leaves the surface of a silicate.We find that rovibrationally excited molecules are ejected into the gas phase immediately after formation over a much wider range of grain temperatures than anticipated. Our results can be explained by the presence of twomechanisms ofmolecule formation that operate in partially overlapping ranges of grain temperature. A preliminary analysis of the relative importance of these two mechanisms is given. These unexpected findings, which will be complemented with experiments on the influence of factors such as silicate morphology, should be of great interest to the astrophysics and astrochemistry communities

Effects of fluoride on primary cultured haemocytes from the marine gastropod Haliotis tuberculata

International audienceAs a consequence of human's activities, fluoride concentration in many aquatic ecosystems is significantly increasing. Nevertheless, little is known about fluoride toxicity to aquatic life. In this study the effect of exposure to different concentrations of sodium fluoride (2, 10, 50, 250 and 1,250 μg mL −1) during 24 h on primary cultured haemocytes of the gastropod Haliotis tuberculata was realized. Results indicate no significant effect of NaF on cell viability, Lysosomal membrane stability, phagocytosis and ROS production at concentrations of 2, 10, 50 and 250 μg mL −1. Nevertheless, lysosomal membrane alterations, a decrease of phagocytosis and morphological changes of H. tuberculata haemocytes were observed at concentration of 1,250 µg mL −1 NaF suggesting a potential impact of NaF at high concentration in the environment

Metastase de la voûte crânienne Revelant un carcinome differencie De la thyroïde

Les métastases des carcinomes thyroïdiens au niveau de la voûte crânienne sont extrêmement rares. Bien que ces métastases soient de mauvais pronostic, la détection précoce et l’administration d’un traitement approprié peuvent améliorer la survie et la qualité de vie. Nous rapportons deux cas de carcinomes différenciés thyroïdiens révélés par une métastase de la voûte crânienne.Mots clés: métastase, voûte crânienne, cancer de la thyroïdeThyroid carcinoma with metastasis to the cranial vault is extremely rare. Although these metastasis had poor prognosis, early detection and administration of appropriate therapy using radioactive iodine seems likely to improve the survival rate and quality of life. We report two cases of differentiated thyroid carcinoma revealed by vault metastasis.Keywords: metastasis, cranial vault, thyroid carcinom

The response of young pistachio trees grown under saline conditions depends on the rootstock

-------------------------------------------------------------------------------------------------------------------------- To cite th is article / Pou r citer cet article Individual trunk cross-sectional area and growth of scion shoots were determined on all trees as well as proline and soluble sugar foliar contents. Results showed that tree growth was affected by both salinity and rootstock. Indeed, trees grafted on P. atlantica rootstock showed a slight early growth advantage compared with those having P. vera as rootstock. For all the treatments, the principal and axillaries shoot length, vegetative bud number and diameter of the trunk cross-sectional areas of stocks were higher on P. atlantica rootstock. On both rootstocks, the salinity at 5 dS/m stimulated the length and bud numbers of axillaries shoots and at 12 dS/m, the growth parameters declined significantly. In highly stressed plants budded on P. vera, proline and soluble sugars contents were higher than control all over the seasons. Keywords. P. vera -P. atlantica

Exploring the 7p22.1 Chromosome as a Candidate Region for Autism

A high incidence of de novo chromosomal aberrations in a population of persons with autism suggests a causal relationship between certain chromosomal aberrations and the occurrence of autism. A previous study on a Tunisian boy carrying a t(7;16) translocation identified the 7p22.1 as a positional candidate region for autism on chromosome 7. The characterization of the chromosomal breakpoints helped us to identify new candidate regions on chromosome 16p11.2 which contain no known genes and the other one on 7p22.1 containing a portion of genes (NP 976327.1, RBAK, Q6NUR6 also called RNF216L and MMD2). We proposed Q6NUR6 (RNF216L) as a candidate gene for autism due to its vicinity to the translocation breakpoint on the chromosome derivative 7. Q6NUR6 is predicted to be an E3ubiquitin-ligase. Quantitative PCR demonstrates that Q6NUR6 gene has an ubiquitous expression and that it is strongly expressed in fetal and adult brain. The Q6NUR6 expression is increased in the patient blood cells in comparison to controls. This is the first report of Q6NUR6 gene (E3 ubiquitin ligase TRIAD3 EC 6.3.2) increasing blood levels in a patient with autism. It's probably caused by a position effect involving this gene and modifying its expression

Volatile Constituents And Antimicrobial Activity Of Lavandula Stoechas L. Oil From Tunisia

International audienceAn oil obtained from the dried leaves of Lavandula stoechas L. in 0.77% yield was analyzed by capillary GC and GUMS. Fenchone (68.2%) and camphor (11.2%) were the main components of the 28 identified molecules. This oil has been tested for antimicrobial activity against six bacteria, and two fungi. The results showed that this oil was active against all of the tested strains; Staphylococcus aureus was the more sensitive strain

De Novo Balanced Translocation t (7;16) (p22.1; p11.2) Associated with Autistic Disorder

The high incidence of de novo chromosomal aberrations in a population of persons with autism suggests a causal relationship between certain chromosomal aberrations and the occurrence of isolated idiopathic autism. We report on the clinical and cytogenetic findings in a male patient with autism, no physical abnormalities and a de novo balanced (7;16)(p22.1;p16.2) translocation. G-banded chromosomes and fluorescent in situ hybridization (FISH) were used to examine the patient's karyotype as well as his parents'. FISH with specific RP11-BAC clones mapping near 7p22.1 and 16p11.2 was used to refine the location of the breakpoints. This is, in the best of our knowledge, the first report of an individual with autism and this specific chromosomal aberration