Search results for "Pica"
showing 10 items of 1408 documents
Contribution des talwegs tropicaux-tempérés aux précipitations d’Afrique australe : quelle évolution dans le cadre du changement climatique ?
2014
6 pages; International audience; Cette étude analyse les changements de la pluviométrie et des talwegs tropicaux-tempérés (TTT) en Afriqueaustrale dans le cadre du changement climatique en utilisant huit modèles climatiques retenus dans l’exercice 5 du GIEC etforcés selon la trajectoire RCP 8.5. Tous les modèles restituent convenablement les bandes nuageuses associées aux TTT,tant en termes de variabilité spatiale que de fréquence d’occurrences. Les modèles divergent sur l’évolution desprécipitations de saison des pluies (NDJF). En revanche, ils montrent tous une diminution du nombre de jours de pluieassociée à une augmentation d’événements plus pluvieux. Ces changements dans la distributio…
Tropical Temperate Toughs over southern Africa: mechanisms and evolution in response to climate change
2015
In the Southern Hemisphere, Southern Africa and the south-west Indian Ocean are one of the three preferred regions where interactions between the tropics and midlatitudes develop. This is the South Indian Convergence Zone (SICZ), where northwest-southeast oriented cloud bands form at the synoptic scale (between 3 and 5 days). These bands are mainly found during the austral summer and are commonly referred to as tropical temperate troughs (TTTs). This research aims at improving our knowledge related to TTTs, with a study on the dynamics associated with these systems, and an analysis of their possible evolution during the 21st century.The first part of this thesis aims at identifying favorab…
Micelles as containers for self-assembled nanodevices: a fluorescent sensor for lipophilicity
2008
Potentiometric titrations, fluorescence versus pH titrations, dynamic light scattering and fluorescence polarization anisotropy studies demonstrate that inside the nanodimensioned Triton X-100 micelles, 1-pyrenecarboxylic acid, PCOO-, forms an apical complex with the Zn2+ cation encircled by a lipophilic cyclen ligand and hugely increasing its fluorescence. The ability of the Zn2+-cyclen-PCOO- complex plus its micellar container to act as a fluorescent sensor to evaluate the lipophilicity of molecular species is demonstrated on the fatty acid series CH 3(CH2)xCOOH (x=0-16). At pH 7.4 a decrease in fluorescence is observed on the addition of fatty acids that is directly related to their chai…
In vitro propagation ofSalix tarraconensis Pau ex Font Quer, an endemic and threatened plant
1996
Salix tarraconensis Pau ex Font Quer, an endemic willow species from northeast Spain, was micropropagated with nodal segments. Shoot multiplication was obtained with different cytokinins, either on Murashige and Skoog medium or woody plant medium. Best results for shoot formation were obtained on Murashige and Skoog medium containing 4.9 μM of 6-γ-γ-dimethylallylaminopurine. Shoots showed strong apical dominance, and some cultures displayed apical necrosis. Benzyladenine gave the worst results; shoots displayed very slow growth, deformed leaves, and hyperhydrity. Good rooting of shoots was obtained with different auxins or without plant growth regulators on woody plant medium. The best resu…
Internodal elongation in the grapevine (<em>Vitis vinifera</em> L.) : leaf influences and role of the shoot apex
1996
<p style="text-align: justify;">The respective influences of the leaves and shoot apex on stimulation of internodal elongation were studied in the grapevine. Various defoliation or decapitation treatments were applied to the shoot of rooted hardwood cuttings grown in a controlled environment chamber.</p><p style="text-align: justify;">Concerning the foliar influences, the role of three sorts of leaves, in relation to their nodal position relative to the internode was analysed ; its own leaves, the leaves located below it and the young leaves neoformed above. The effects produced by excision of these different leaves show that the two adjacent leaves (below and above) of th…
Investigations on the geographical variability of the human transferrins.
1971
On the basis of own and from the widely scattered literature compiled materials the geographical distribution of the transferrin alleles is discussed. They reveal a characteristic distribution pattern, as the slow Tf variants produced by TfD alleles are obviously more frequent in tropical than in non-tropical populations. Considering similar results in cattle and its interpretation by Ashton (1958, 1965), it is hypothesized, that the relatively high TfΓ frequencies in tropical biotops might be a selective adaptation to their special climatic conditions. In this connection an association between slowly moving transferrin proteins in man and tolerance to hotter climates — as could be found in…
Control of end-of-life oxygen-containing groups accumulation in biopolyesters through introduction of crosslinked polysaccharide particles
2021
The formulation of bio-based materials with good performance in service and controlled end-of-life is imperative for an effective circular economy. In this work, an innovative approach to induce and control the end-of-life of biodegradable polyesters through introduction of crosslinked polysaccharide particles is proposed. Chitosan (Ch) has been subjected to ionotropically crosslinking and then added to polylactic acid (PLA) at different amounts (1.0–4.0%w) by melt mixing. All obtained results suggest that the addition of crosslinked Ch (cCh) particles does not modify significantly the investigated biopolyester properties. Specifically, the thermal analysis of the composites reveals that th…
Topical Anti-Inflammatory Lignans from Haplophyllum hispanicum Haplophyllum hispanicum
1996
The present paper reports the results of the methanol extract of Haplophyllum hispanicum Spach on single or repeated local 12-O-tetradecanoylphorbol acetate (TPA) administration and in the oxazolone-induced contact-delayed hypersensitivity mouse ear edemas. Two topical anti-inflammatory aryl naphthalide lignans were isolated from the active fractions of the methanol extract. They were identified by spectroscopic methods, including 13C NMR and heteronuclear multiple bond correlation (HMBC), as diphyllin acetyl apioside and tuberculatin. The former was the most active on acute TPA edema with a ID50 of 0.27 μmol/ear
Estudio de la velocidad de curación ósea tras la realización de la cirugía periapical mediante la tomografía computarizada de haz cónico
2022
Introducción: el objetivo de este estudio fue evaluar, tras la realización de la cirugía periapical, la velocidad de curación (por mes) del hueso apical y el resultado final de la curación ósea, desde el punto de vista de la tomografía computarizada de haz cónico (TCHC). También se tuvieron en cuenta la relación entre la velocidad y la calidad de curación ósea con los factores clínicos preoperatorios. Métodos: se buscó en una base de datos clínica los pacientes que habían recibido cirugía periapical y además disponían de una THCH antes y después de la operación. Se realizó un análisis volumétrico de las imágenes pre y postoperatorias, para ello se utilizó el programa de software Planmeca (P…
Green coffee, bioactive compounds’ analysis of experimental cultivation in Sicily: a new frontier in the Sicilian food sector
2023
Recently, climate change represents a new possibility for tropical cultivars fruit in Mediterranean areas. The focus of this work is the evaluation of the real possibility of coffee cultivation in Sicily, like coffee plants grown in tropical and subtropical regions. The objective was to evaluate plant adaptation to our climate and to study the chemical qualities of green coffee pulps and seeds: total phenolic content, antiradical capacity, fatty acids, amino acids, alkaloids, vitamins, proximate composition, polyphenolic profile and other bioactive compounds of cosmetic, pharmaceutical and agrary interest. Temperature, light and vegetative growth of Coffea arabica L. cv. “Caturra” plants we…