Influence of the ionic composition on the diffusion mass transfer of saccharides through a cation-exchange membrane

Recent studies have pointed out that the presence of salts can change significantly the membrane process performances because of the resulting modification of the neutral solutes transfer through the membrane. The influence of the ionic composition on the transfer of neutral solutes through membranes could be explained by a modification of the membrane properties, due to electrostatic effects, by a modification of the solute radius, likely due to its dehydration induced by the electrolyte, or more probably by a combination of both. This study deals with the investigation of the mechanisms governing the mass transfer of neutral species through an ion-exchange membrane used in electrodialysis, CMX, with a focus on the role of ions. The mass transfer of various saccharides (xylose,glucose and sucrose) as well as the solvent transfer in different electrolytic solutions (NaCl,NH 4Cl, CaCl 2 and MgCl 2) was studied in a diffusion regime. A specific procedure has been used to dissociate the solvent or solute fluxes variations due to the modifications of the solute properties and of the membrane material induced by the electrolyte. The results showed that the transfer modification is mainly due to the influence of the electrolyte on the membrane properties, which is fixed by the membrane soaking. A quantitative correlation has been established between the solvent and solute transfer and the hydration number of the membrane counterion. In presence of electrolyte, the saccharide mass transfer increased but the impact of the presence of electrolyte is much less than the one of membrane soaking. However, in this case, a relationship has been also established between the increase of the saccharide mass transfer and the cation hydration state

Quartiers et effets de quartier. Analyse de la variabilité de la taille des quartiers perçus dans l'agglomération parisienne

International audienceThe present paper aims to discuss standardized and rigid approaches to neighborhood existing in the literature on neighborhood effects. Investigating the perceived neighborhoods of 650 inhabitants of the Paris metropolitan area (« Santé, Inégalités et Ruptures Sociales » survey), we first analyze the variability in size of perceived neighborhoods according to the urban and social characteristics of residential areas, but also according to the sociodemographic profiles of inhabitants and their neighborhood experiences. As perceived neighborhoods are found to be five times larger in Paris than in small suburban municipalities and four times larger in rich than in poor areas, we aim to underline errors in estimation and interpretation of neighborhood effects which may emerge in studies when they consider « constant size neighborhoods » (e.g. administrative units or circular areas) and neglect the different capacities that populations have in experiencing their neighbourhood of residence.Cet article propose de discuter des approches rigides et standardisées du quartier qui prévalent dans les études sur les « effets de quartier ». En étudiant les zones que plus de 650 habitants de l'agglomération parisienne (enquête SIRS « Santé, Inégalités et Ruptures Sociales ») définissent comme étant leur quartier de résidence, il s’agit d’abord d’analyser comment la taille des quartiers perçus varie selon la morphologie urbaine et sociale des espaces résidentiels mais aussi selon le profil sociodémographique des habitants et leurs rapports au quartier. Après avoir constaté que les habitants de Paris intra-muros et des espaces socialement favorisés perçoivent leur quartier comme une zone sensiblement plus étendue que les autres habitants, l’idée est de souligner les erreurs de quantification et d'interprétation des effets de quartier auxquels s’exposent les études lorsqu’elles considèrent les quartiers comme des unités spatiales de taille constante (mailles administratives ou zones circulaires) et négligent ainsi les capacités différenciées des populations à s'approprier leur quartier de résidence

Prior expectations of leadership programme attendees and their subsequent reflections on completion thereof

This article describes the reflections of nursing academics on their personal expectations prior to commencement of a leadership programme and their subsequent reflections on completion of this introduction to the leadership programme. The programme aimed at developing the participants as leaders in conjunction with developing the culture of research in a school of nursing at a university in the Western Cape, South Africa. A qualitative, exploratory and descriptive design was used. A total sample of eight nursing academics at a higher education institution (HEI) took part and narratives were written in July 2012. The results indicated active participation and involvement; development of skills and knowledge; a balance between programme and personal goals; a sense of confidence amongst attendees; creating structure for growth; and critical thinking. The implication of the study was that a leadership research team has been established with clear underlying assumptions of transformative leadership in research driven by self-leadership.Department of HE and Training approved lis

DArT whole genome profiling provides insights on the evolution and taxonomy of edible Banana (Musa spp.)

Background and Aims: Dessert and cooking bananas are vegetatively propagated crops of great importance for both the subsistence and the livelihood of people in developing countries. A wide diversity of diploid and triploid cultivars including AA, AB, AS, AT, AAA, AAB, ABB, AAS and AAT genomic constitutions exists. Within each of this genome groups, cultivars are classified into subgroups that are reported to correspond to varieties clonally derived from each other after a single sexual event. The number of those founding events at the basis of the diversity of bananas is a matter of debate. Methods: We analysed a large panel of 575 accessions, 94 wild relatives and 481 cultivated accessions belonging to the section Musa with a set of 498 DArT markers previously developed. Key Results: DArT appeared successful and accurate to describe Musa diversity and help in the resolution of cultivated banana genome constitution and taxonomy, and highlighted discrepancies in the acknowledged classification of some accessions. This study also argues for at least two centres of domestication corresponding to South-East Asia and New Guinea, respectively. Banana domestication in New Guinea probably followed different schemes that those previously reported where hybridization underpins the emergence of edible banana. In addition, our results suggest that not all wild ancestors of bananas are known, especially in M. acuminata subspecies. We also estimate the extent of the two consecutive bottlenecks in edible bananas by evaluating the number of sexual founding events underlying our sets of edible diploids and triploids, respectively. Conclusions: The attribution of clone identity to each sample of the sets allowed the detection of subgroups represented by several sets of clones. Although morphological characterization of some of the accessions is needed to correct potentially erroneous classifications, some of the subgroups seem polyclonal

Managing banana genetic resources and genomic information with the Triplet Drupal/Tripal/Chado [P0944]

Unraveling the genetic diversity held in genebanks on a large scale is underway, given the advances in NGS-based technologies that produce high-density genetic markers for a large number of samples at low cost. As SNP markers are being mapped on the reference genomes, it is important to develop interoperable system for managing both genomic data and genetic resources. The latter are often managed through bespoke information systems. The Musa Germplasm Information System (MGIS), the main banana genetic resource website, has recently been developed to address those needs in a convenient and flexible way. First of all, we decided to head for a generic database schema, such as CHADO, and to use a robust content management system such as Drupal as the web interface. The Tripal module provides the "glue" between these two parts and drastically reduces development time. Using this trio, we were able to quickly recreate in few months a complete and scalable site and expand it with new features. We now have a germplasm management system allowing collection browsing, and accession browsing, searching and ordering. Accession passport data have been enriched by geographical data, phenotyping characterization data, and information from diversity studies based on molecular markers and SNPs. As a first-use case, such genotyping studies allow linking with the Banana Genome Hub (BGH) website to explore these data in the genome context. (Texte intégral

A genome-wide association study on the seedless phenotype in banana (Musa spp.) reveals the potential of a selected panel to detect candidate genes in a vegetatively propagated crop

Banana (Musa sp.) is a vegetatively propagated, low fertility, potentially hybrid and polyploid crop. These qualities make the breeding and targeted genetic improvement of this crop a difficult and long process. The Genome-Wide Association Study (GWAS) approach is becoming widely used in crop plants and has proven efficient to detecting candidate genes for traits of interest, especially in cereals. GWAS has not been applied yet to a vegetatively propagated crop. However, successful GWAS in banana would considerably help unravel the genomic basis of traits of interest and therefore speed up this crop improvement. We present here a dedicated panel of 105 accessions of banana, freely available upon request, and their corresponding GBS data. A set of 5,544 highly reliable markers revealed high levels of admixture in most accessions, except for a subset of 33 individuals from Papua. A GWAS on the seedless phenotype was then successfully applied to the panel. By applying the Mixed Linear Model corrected for both kinship and structure as implemented in TASSEL, we detected 13 candidate genomic regions in which we found a number of genes potentially linked with the seedless phenotype (i.e. parthenocarpy combined with female sterility). An additional GWAS performed on the unstructured Papuan subset composed of 33 accessions confirmed six of these regions as candidate. Out of both sets of analyses, one strong candidate gene for female sterility, a putative orthologous gene to Histidine Kinase CKI1, was identified. The results presented here confirmed the feasibility and potential of GWAS when applied to small sets of banana accessions, at least for traits underpinned by a few loci. As phenotyping in banana is extremely space and time-consuming, this latest finding is of particular importance in the context of banana improvement. (Résumé d'auteur