L’évolution de la polygamie en milieu rural sénégalais : institution en crise ou en mutation ?

On annonce depuis longtemps le déclin de la polygamie en Afrique. Pourtant, ces pratiques restent courantes dans de nombreux pays de la région, surtout en milieu rural. Depuis les années 1970, la crise économique et agricole a entraîné de profonds changements dans l’organisation des ménages et laisse entrevoir une remise en question des fondements de la polygamie. L’étude de l’évolution de la polygamie dans la zone d’étude de Niakhar, au Sénégal, met en évidence la complexité des forces en jeu : bien que les niveaux restent stables au cours du temps, les hommes des générations récentes entrent en première union polygame moins rapidement que leurs aînés. En combinant des données qualitatives avec celles d’une enquête biographique rétrospective, cette étude vise à identifier quels processus influent sur le calendrier d’entrée en union polygame des hommes au fil des générations. La confrontation des différentes données laisse croire à l’adoption d’attitudes visant la redéfinition des fondements de la polygamie plutôt que sa remise en question, redéfinition ayant pour objectif d’en assurer la pérennité.The decline of polygyny in sub-Saharan Africa has been predicted for decades but the levels remain high in many countries, especially in rural areas. Since the 1970s, the economic and agricultural crisis has strongly affected household organization, suggesting that the bases for polygamy might be in question. The study of polygamous behaviours in the Niakhar rural area in Senegal highlights the different forces at work: despite relatively stable levels in recent decades, younger men are entering their first polygamous union later than their elders. By combining qualitative data with the results of a retrospective biographical survey, this study seeks to identify the processes that affect the timing of men’s first polygamous union across different cohorts. The results suggest an adoption of new attitudes, involving a redefinition of the bases for polygamy (rather than a questioning of polygamy), in order to ensure the continuation of such practices

Optical Scar in a chaotic fibre

We propose to use a multimode optical fiber with a D-shaped cross section as a privileged system to image wavefunctions of a chaotic system. Scar modes are in particular the sub ject of our investigations. We study their imprints on the statistics of intensity and we show how the introduction of a localized gain region in the fiber is used to perform a selective excitation of scar modes.Comment: 13 page

Control of anthocyanin biosynthesis pathway gene expression by eutypine, a toxin from Eutypa lata, in grape cell tissue cultures

Eutypine, 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzaldehyde, is a toxin produced by Eutypa lata, the causal agent of Eutypa dieback in grapevine. The effect of the toxin on anthocyanin synthesis has been investigated in Vitis vinifera cv. Gamay cell cultures. At concentrations higher than 200 μmol/L, eutypine reduced anthocyanin accumulation in cells. The reduction in anthocyanin accumulation was proportional to the eutypine concentrations and HPLC analysis showed that eutypine affected the levels of all anthocyanins. The effect of eutypine application on the expression of five genes of the anthocyanin biosynthesis pathway, including chalcone synthase (CHS), flavonone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX), and UDP glucose- flavonoid 3-O-glucosyl transferase (UFGT) was determined. Expression of CHS, F3H, DFR and LDOX was not affected by the addition of eutypine to grapevine cell cultures. In contrast, expression of the UFGT gene was dramatically inhibited by the toxin. These results suggest that in grapevine cell cultures, eutypine strongly affects anthocyanin accumulation by inhibiting UFGT gene expression. The mechanism of action of eutypine is discussed

Familias en el Viejo y el Nuevo Mundo

En este libro no se pretende hacer un balance de aportaciones recientes, sino que, teniendo como eje de desarrollo el concepto de “familia” en un amplio sentido, demográfico y social, se intenta integrar las perspectivas micro-analíticas –estudio de familias específicamente desarrolladas a ambos lados del Atlántico, familias virreinales, de la nobleza, la administración e incluso la Iglesia- y las regionales –de territorios especialmente afectados por el paso de sus habitantes a América-, al lado de la dimensión “macro” derivada de los estudios de las estructuras familiares en América y en la Península Ibérica y de las migraciones entre ambos espacios. Ese enfoque múltiple es el fundamento mismo de la comparación y de la complementariedad: un conjunto de lecturas diversas respecto a las teorías generalizadoras, la aplicación de métodos distintos y a las aportaciones y problemas de las fuentes documentales diferentes son esenciales en esta monografía; un eje que se refiere a cómo el modelo familiar castellano se impuso por medio de la legislación en América durante la colonización y, más allá, cómo se integró en las sociedades autóctonas y acabó mezclándose con los modelos locales; finalmente un eje dedicado a las migraciones y el paso a América como nexo entre las familias de ambos lados.Es revisado por: http://sedici.unlp.edu.ar/handle/10915/78430Facultad de Humanidades y Ciencias de la Educació

Selective amplification of scars in a chaotic optical fiber

In this letter we propose an original mechanism to select scar modes through coherent gain amplification in a multimode D-shaped fiber. More precisely, we numerically demonstrate how scar modes can be amplified by positioning a gain region in the vicinity of specific points of a short periodic orbit known to give rise to scar modes