The influence of the thickness of the Cds emitter layer on the performance of a CIGS solar cell with acceptor defects

In this work, we simulated a solar cell based on CIGS with simple default acceptor, using software (SCAPS) version 3.302 in order to study certain parameters. In particular, we have varied the thickness of the CdS emitter (0.05 mum, 0.04 mum and 0.03 mum) to study its influence on the performance of the cell. We were able to record that the energy efficiency increased from 16.50% for a thickness of 0.05 mum of the emitter to 16.87% for a thickness of 0.03 mum of the emitter. We also noted an improvement in other parameters, such as the form factor from FF = 79.81% to 80.10%, with the decrease in the thickness of the CdS. And from the Nyquist diagram, we also determined parameters like the series resistance to get an idea on the equivalent electrical circuit of the studied cell

Finite-size scaling analysis of the distributions of pseudo-critical temperatures in spin glasses

Using the results of large scale numerical simulations we study the probability distribution of the pseudo critical temperature for the three-dimensional Edwards-Anderson Ising spin glass and for the fully connected Sherrington-Kirkpatrick model. We find that the behavior of our data is nicely described by straightforward finite-size scaling relations.Comment: 23 pages, 9 figures. Version accepted for publication in J. Stat. Mec

Genetic variation and host-parasite specificity of Striga resistance and tolerance in rice: the need for predictive breeding

The parasitic weeds Striga asiatica and Striga hermonthica cause devastating yield losses to upland rice in Africa. Little is known about genetic variation in host resistance and tolerance across rice genotypes, in relation to virulence differences across Striga species and ecotypes. Diverse rice genotypes were phenotyped for the above traits in S. asiatica- (Tanzania) and S. hermonthica-infested fields (Kenya and Uganda) and under controlled conditions. New rice genotypes with either ecotype-specific or broad-spectrum resistance were identified. Resistance identified in the field was confirmed under controlled conditions, providing evidence that resistance was largely genetically determined. Striga-resistant genotypes contributed to yield security under Striga-infested conditions, although grain yield was also determined by the genotype-specific yield potential and tolerance. Tolerance, the physiological mechanism mitigating Striga effects on host growth and physiology, was unrelated to resistance, implying that any combination of high, medium or low levels of these traits can be found across rice genotypes. Striga virulence varies across species and ecotypes. The extent of Striga-induced host damage results from the interaction between parasite virulence and genetically determined levels of host-plant resistance and tolerance. These novel findings support the need for predictive breeding strategies based on knowledge of host resistance and parasite virulence

Theta Vectors and Quantum Theta Functions

In this paper, we clarify the relation between Manin's quantum theta function and Schwarz's theta vector in comparison with the kq representation, which is equivalent to the classical theta function, and the corresponding coordinate space wavefunction. We first explain the equivalence relation between the classical theta function and the kq representation in which the translation operators of the phase space are commuting. When the translation operators of the phase space are not commuting, then the kq representation is no more meaningful. We explain why Manin's quantum theta function obtained via algebra (quantum tori) valued inner product of the theta vector is a natural choice for quantum version of the classical theta function (kq representation). We then show that this approach holds for a more general theta vector with constant obtained from a holomorphic connection of constant curvature than the simple Gaussian one used in the Manin's construction. We further discuss the properties of the theta vector and of the quantum theta function, both of which have similar symmetry properties under translation.Comment: LaTeX 21 pages, give more explicit explanations for notions given in the tex

Quantification de la biomasse aérienne des palétuviers du genre Rhizophora au Delta du Saloum (Sénégal)

L’étude de la biomasse aérienne des palétuviers a fait l’objet d’un  inventaire dans quatre unités d’échantillonnage. Quinze parcelles  permanentes ont aussi permis d’étudier les effets de certains facteurs dumilieu sur la biomasse. Dans les strates de hauteur moyenne, la biomasse sèche des racines aériennes la plus élevée est de 67 tonnes à l’hectare chez R. mangle. Dans les strates hautes, celle la plus élevée est de 83,3tonnes à l’hectare. Ces deux grandes quantités de biomasse racinaire supportent aussi les biomasses sèches de tiges et autres parties les plus élevées dans la zone. En termes de comparaison, le pic de la biomasse sèche des tiges et autres parties est observé chez R. mangle. Quant à la biomasse racinaire sèche, le pic est noté chez R. racemosa/harisonnii. Dans les strates de hauteur moyenne, la biomasse sèche des tiges et autres parties est en général plus élevée que celle des racines. Dans les strates hautes, ces rapports de biomasse sont inversés. L’analyse de corrélation entre la biomasse racinaire et les facteurs étudiés montre que l’augmentation de celleci est plus liée à la hauteur de submersion qu’au type de sol. Cette augmentation serait le résultat d’une adaptation morphologique des palétuviers aux vasières meubles et à leur  submersion.Mots clés : Biomasse sèche, strates, milieu, racinaire, tiges, autres parties

White Paper: Shifting the goal post - from high impact journals to high impact data

The purpose of this white paper is to provide an overview of the ongoing initiatives at center level to respond to changing public expectations and to the challenge of improving the conduct of science by making research data widely available. We also attempt to provide a framework for implementing open access for research data to maximize CGIAR’s impact on development. The remainder of this paper proceeds as follows; firstly a summary of the diversity of research data produced by the centers is given, followed by an overview of the existing infrastructure for data management for each Center. Secondly, some of the limitations and barriers faced by the centers in their process to mainstream research data publishing are addressed. The paper concludes with recommendations for how these limitations and barriers can be tackled

Pharyngeal carriage of Neisseria species in the African meningitis belt.

OBJECTIVES: Neisseria meningitidis, together with the non-pathogenic Neisseria species (NPNs), are members of the complex microbiota of the human pharynx. This paper investigates the influence of NPNs on the epidemiology of meningococcal infection. METHODS: Neisseria isolates were collected during 18 surveys conducted in six countries in the African meningitis belt between 2010 and 2012 and characterized at the rplF locus to determine species and at the variable region of the fetA antigen gene. Prevalence and risk factors for carriage were analyzed. RESULTS: A total of 4694 isolates of Neisseria were obtained from 46,034 pharyngeal swabs, a carriage prevalence of 10.2% (95% CI, 9.8-10.5). Five Neisseria species were identified, the most prevalent NPN being Neisseria lactamica. Six hundred and thirty-six combinations of rplF/fetA_VR alleles were identified, each defined as a Neisseria strain type. There was an inverse relationship between carriage of N. meningitidis and of NPNs by age group, gender and season, whereas carriage of both N. meningitidis and NPNs was negatively associated with a recent history of meningococcal vaccination. CONCLUSION: Variations in the prevalence of NPNs by time, place and genetic type may contribute to the particular epidemiology of meningococcal disease in the African meningitis belt

Yield loss of Oryza glaberrima caused by grain shattering under rainfed upland conditions

The general perception of Oryza glaberrima as low yielding is a potential drawback to intraspecific breeding of this species. Yields of 21 O. glaberrima accessions were evaluated alongside four O. sativa check varieties under two conditions in which panicles were both covered by paper sacks to avoid grain shattering (potential yield plot) and also not covered (control plot) in a rainfed upland field of Benin in 2010 and 2011. Average potential yields of O. glaberrima with panicles covered were 2.42 and 3.65 t ha-1 in 2010 and 2011, respectively, while those of O. sativa were respectively 2.99 and 3.49 t ha-1. Although there was no significant difference between potential yield and control yield in O. sativa, 19 O. glaberrima accessions showed significant yield reduction by grain shattering — the average percentages of lost yield by shattering were 57.88% in 2010 and 66.76% in 2011. These results suggest that low yield of O. glaberrima is due to grain shattering and that its potential yield would not be inferior to O. sativa if the grain shattering problems were overcome. Two O. glaberrima accessions, TOG 12303 and TOG 9300, possessing strong resistance to grain shattering comparable to O. sativa checks, were identified.Keywords: Panicles, paper sacks, potential yield, yield reduction

Diagnostic et caractérisation microbiologique des procédés artisanaux de fabrication de boissons et de concentrés d’Hibiscus sabdariffa L au Sénégal

L’Hibiscus sabdariffa L. est une plante très utilisée au Sénégal et presque dans toute l’Afrique de l’ouest. Les calices sont transformés en boisson, en concentré, en poudre, etc. par des petites et moyennes entreprises (PME) et des Groupements d’intérêt économiques (GIE). Les procédés de fabrications sont presque similaires avec quelques petites différences dans les entreprises. Cependant toutes les exigences des bonnes pratiques de fabrication et de suivi des lots ne sont pas systématiquement respectées comme la mise en place du plan HACCP (Hazard Analysis Critical Control Point) et un suivi sur le plan microbiologique des produits. Ainsi, l’objectif de ce travail est d’évaluer les diagrammes de fabrication de boissons et concentrés de bissap et de réaliser le contrôle microbiologique sur toutes les étapes du process dans 2 PME. Les visites effectuées sur les lieux de production ont permis de retracer tous les diagrammes de fabrication des différents produits. Et l’analyse microbiologique a été faite sur des échantillons prélevés au niveau de chaque étape du procédé. Les techniques classiques de la microbiologie alimentaire ont été utilisées pour la recherche de chaque germe selon les référentiels en vigueurs.Les résultats microbiologiques ont révélé une absence totale de bactéries pathogènes sur tout le procédé de transformation. Seule la présence de FMAT (Flore Mésophile Aérobie Totale), de levures et moisissures a été observée sur les échantillons. Cependant la présence d’un type de levure absente sur les matières premières a été notée sur toutes les étapes de la transformation. De plus le suivi microbiologique effectué sur un lot de production stocké à différentes températures (4, 10, 20, 30 et 37°C) pendant six mois a montré que le produit fini qui était salubre au départ présentait une certaine flore dont la quantité dépassait les valeurs seuils en vigueur. Le développement était plus remarqué sur les échantillons conservés à 4°C. Les résultats ont montré la présence d’une contamination croisée dont l’origine peut être diverse (personnel ; environnement, matériel). Pour étayer ce problème des études moléculaires de caractérisation permettant d’identifier les sources de contamination devront être menées de même que l’instauration d’un plan de suivi des bonnes pratiques d’hygiène et de fabrication.Mots-clés: procédé, microbiologie, boissons, concentrés d’Hibiscus sabdariffa. Diagnostic and microbiological characterization of artisanal processes of drinks and concentrates Hibiscus sabdariffa L SenegalHibiscus sabdariffa L. is a plant widely used in Senegal and almost throughout West Africa. Chalices are transformed into drink, concentrate, powder, etc. by small and medium enterprises (SMEs) and Groupings of economic interest grouping (EIG). The manufacturing processes are almost similar with few differences However, all the requirements needed in good manufacturing practices and lots monitoring are not always respected as the implementation of the HACCP plan (Hazard Analysis Critical Control Point) and the microbiologically follow of products. The objective of this study was to evaluate diagrams manufacture of beverages and concentrates bissap and perform microbiological control over all stages of the process in 2 SMEs. The visits to the places of production have allowed us to trace all the diagrams of manufacturing different products and microbiological analysis was performed on samples taken at each step of the process. Conventional techniques of food microbiology were used to research each seed according standard repository. Microbiological results revealed a complete absence of any pathogenic bacteria on the method of transformation. Only the presence of two floras FMAT, yeast and mold was observed on the samples analyzed. However, we noticed the presence of a type of yeast on all stages of processing but not commodities. Microbiological monitoring on a batch production is stored at various temperatures (4, 10, 20, 30 and 37°C) for six months shows that the finished product was wholesome initially showed some flora whose amount exceeds the threshold values in force. The development was noted on more samples stored at 4°C. These results showed the presence of cross-contamination whose origin is diverse (personnel environment and material). In support of this problem of molecular characterization studies to identify sources of contamination will be conducted as well as the establishment of a monitoring plan good hygiene and manufacturing practices.Keywords: process, microbiology, drinks, concentrates of Hibiscus sabdariffa