Informality, Trade Policies And Smuggling In West Africa

In West Africa, recorded intra-regional trade is small but informal cross-border trade (ICBT) is pervasive, despite regional integration schemes intended to promote official trade. We argue that ICBT must be understood in light of two features of West African national boundaries: divergent economic policies between neighboring countries and the ease with which informal operators can ship goods across borders. We focus on two ICBT clusters: Senegal–The Gambia and Nigeria–Benin–Togo. Nigeria and Senegal have protected their domestic industries with high import barriers, whereas Benin, Togo and The Gambia have maintained lower import taxation. These differential trade policies, together with high mobility of goods and people across borders, lead to widespread smuggling, with goods imported legally in low-tax countries and re-exported unofficially to countries with higher import duties

Alteration of post harvest diseases of mango Mangifera indica through production practices and climatic factors

Mango production in Senegal takes place over the two seasons of dry and humid conditions between April and November. The increasing demand for fresh mangoes has led to an increase in land areaallocated to that crop. Mango production suffers, however, from fruit rotting due to post-harvest diseases during ripening. These diseases reduce the fruit quality and cause severe losses. A surveywas carried out in 2004 to detect fungi involved in post-harvest rot of mangoes (cv. Kent) produced in the Niayes area of Senegal in relation with the production practices and the climatic conditions. Theresults showed that at first harvest during the dry season, a broader species range of fungi including Alternaria sp., Botryodiplodia theobromae, Dothiorella sp., Aspergillus niger and non-identified fungiwere responsible for mango rotting. The fruits harvested during the humid season, however, were more heavily infested but a smaller number of fungal agents were involved; Colletotrichum gloeosporioidesand secondarily Phoma mangiferae played the main role. The cultural practices played an important role on mango infection whereby orchard sanitation and particularly cleaning and pruning reduced theinfection rates. Orchards with no care, in contrast, yielded the most heavily infested mango samples. In addition, the harvest practice of inversion of fruits in soil for sap elimination increases contaminationwith pathogenic fungi

The Informal Sector In Francophone Africa: Firm Size, Productivity, And Institutions

This book is a major step towards improving the understanding of the complex reality of informal sector firms in francophone West Africa. It innovates by concentrating on informal firms rather than informal employment (as other studies do), and identifying \u27large informal\u27 sector firms whose sales rival those of large formal-sector firms but operate in ways that are similar to small informal operators. Not only is the regulatory environment facing these two types of informal firms distinct, but policies aimed at improving their productivity need to be differentiated. This study focuses on the urban informal sector in three capital cities: Dakar (Senegal), Cotonou (Benin), and Ouagadougou (Burkina Faso). The study also breaks new ground with an eclectic methodology and primary data collection. Quantitative and qualitative firm-level data were collected involving a unique and fruitful collaboration among academic researchers, government officials, the West African economic and monetary union commission, informal and formal sector business associations, and labor unions. This volume represents the culmination of a long collaboration between the Centre de Recherches Economiques Appliquees (CREA) at the University Cheikh Anta Diop of Dakar and the World Bank

Les Cyanophyceae marines de l’île de Ngor (Sénégal)

La présente étude a été initiée dans le but de déterminer la composition taxonomique et la structure des peuplements de Cyanophyceae au niveau de l’ile de Ngor. Durant les travaux, une description basée sur des caractères morphologiques du thalle (cellule, colonie ou filament) des taxa a été effectuée. Aussi une classification et un inventaire systématique de ces taxa ont été réalisés. Six prélèvements ont été effectués entre juillet 2009 et août 2010 dans les eaux marines de l’île de Ngor située à 800 m de la côte dakaroise (Sénégal). L’observation des différents échantillons prélevés a permis de répertorier au niveau de cet écosystème 38 taxa de Cyanophyceae dont 28 identifiées jusqu’au niveau spécifique, réparties en 18 genres et 11 familles. Sur ces 11 familles, seules trois d’entre elles regroupent plus de la moitié des taxa présents. Ce sont les Oscillatoriaceae avec 31,56%, les Phormidiaceae et les Pseudanabaenaceae avec chacune 15,79%. Les Merismopediaceae représentent 10,53% des taxa, les Chroococcaceae 7,89%, et les Synechococcaceae 5,26%. Les familles des Borziaceae, des Xenococcaceae, des Hyellaceae, des Microcystaceae et des Rivulariaceae ne représentent chacune que 2,63%. Pour ce qui est des genres, Oscillatoria Vaucher est le plus représenté avec 7 taxa, suivi des genres Lyngbya C. Agardh et Phormidium Kütz. Ex Gom. avec chacun 4 taxa. Sur les 28 taxa identifiés jusqu’au niveau espèce, 17 ont été décrits pour la 1ere fois au Sénégal.Mots-clés : Cyanophyceae, composition taxonomique, structure, île de Ngor, Sénéga

The transcriptome of metamorphosing flatfish

Background Flatfish metamorphosis denotes the extraordinary transformation of a symmetric pelagic larva into an asymmetric benthic juvenile. Metamorphosis in vertebrates is driven by thyroid hormones (THs), but how they orchestrate the cellular, morphological and functional modifications associated with maturation to juvenile/adult states in flatfish is an enigma. Since THs act via thyroid receptors that are ligand activated transcription factors, we hypothesized that the maturation of tissues during metamorphosis should be preceded by significant modifications in the transcriptome. Targeting the unique metamorphosis of flatfish and taking advantage of the large size of Atlantic halibut (Hippoglossus hippoglossus) larvae, we determined the molecular basis of TH action using RNA sequencing. Results De novo assembly of sequences for larval head, skin and gastrointestinal tract (GI-tract) yielded 90,676, 65,530 and 38,426 contigs, respectively. More than 57 % of the assembled sequences were successfully annotated using a multi-step Blast approach. A unique set of biological processes and candidate genes were identified specifically associated with changes in morphology and function of the head, skin and GI-tract. Transcriptome dynamics during metamorphosis were mapped with SOLiD sequencing of whole larvae and revealed greater than 8,000 differentially expressed (DE) genes significantly (p < 0.05) up- or down-regulated in comparison with the juvenile stage. Candidate transcripts quantified by SOLiD and qPCR analysis were significantly (r = 0.843; p < 0.05) correlated. The majority (98 %) of DE genes during metamorphosis were not TH-responsive. TH-responsive transcripts clustered into 6 groups based on their expression pattern during metamorphosis and the majority of the 145 DE TH-responsive genes were down-regulated. Conclusions A transcriptome resource has been generated for metamorphosing Atlantic halibut and over 8,000 DE transcripts per stage were identified. Unique sets of biological processes and candidate genes were associated with changes in the head, skin and GI-tract during metamorphosis. A small proportion of DE transcripts were TH-responsive, suggesting that they trigger gene networks, signalling cascades and transcription factors, leading to the overt changes in tissue occurring during metamorphosis

La syringomyelie foraminale : a propos de 4 cas

Introduction La syringomyélie foraminale est une cavité intramédullaire habituellement cervicale remplie de liquide cérébrospinal consécutive à une perturbation de sa circulation extra-médullaire due à un obstacle. La clinique permet de rattacher les symptômes à la souffrance de la moelle cervicale. Compte tenu de nos condition de travail, le diagnostic peut errer longuement ce d’autant plus que l’IRM qui est le principal élément diagnostique n’est pas demandé de façon routinière du fait son coût élevé. Le traitement est essentiellement chirurgical et plusieurs attitudes ont été proposées.Objectif Rapporter l’expérience de notre service dans la prise en charge de cette affection.Methodologie Il s’agit d’une étude rétrospective portant sur tous les cas de syringomyélie foraminale pris en charge dans le service de neurochirurgie de Dakar de janvier 2009 à Juin 2010.Resultats Quatre cas ont été relevés : 1 patient de sexe masculin et 3 de sexe féminin. Les âges étaient respectivement de 18, 22, 30 et 38 ans. Trois (3) patients ont présenté un syndrome lésionnel suspendu ; 3 un syndrome sous lésionnel ; 2 un syndrome sus-lésionnel et 2 des troubles trophiques. L’IRM a montré une cavité syringomyélique associée à une malformation de d’Arnold Chiari type 1 dans tous les cas. Le traitement chirurgical a consisté en une décompression osseuse occipito - C1 dans 2 cas et à une décompression ostéo durale occipito - C1 dans les 2 autres cas.Conclusion La syringomyélie est une affection relativement rare qui se révèle à l’âge adulte bien qu’il s’agisse d’une malformation congénitale (malformation d’Arnold Chiari). Dans notre contexte de travail, les patients consultent le plus souvent à un stade avancé et le syndrome lésionnel peut manquer (probablement masqué par les autres syndromes) ce qui rend le diagnostic clinique de syringomyélie difficile. L’IRM doit être réalisée le plus tôt possible devant toute symptomatologie de souffrance médullaire cervicale car le scanner du rachis cervical est peu contributif.Mots clés : syringomyélie, malformation de Chiari, syndrome lésionnel, décompression chirurgicale

Ultra Large Castings to Produce Low Cost Aluminum Vehicle Structures

Through a cooperative effort with the U.S. Department of Energy (DOE) Office of Heavy Vehicle Technologies (OHVT), Alcoa is developing a casting process to produce ultra large thin wall components. The casting process is a low pressure, metal mold, multiport injection vertical casting process. The specific system for demonstration of the process is located at Alcoa's Technology Center and will be capable of producing parts extending 3 M long, 1.7 M wide and 0.4 M high. For example, single castings of car floor pan frames or side wall aperture structures are candidates for this installation. This shall provide a major opportunity to reduce the cost of lightweight transportation vehicle structures by (a) reducing the components or part count and (b) reducing the cost of assembly. To develop and demonstrate the process, an inner panel of the Chrysler minivan liftgate will be first produced on this system. Through computer analyses, the cast inner panel design was developed to satisfy both structural performance and casting process requirements. Currently, this is an 11 part assembly of steel components. At the time of this abstract, the numerous system components are in various phases of fabrication and site preparation is fully underway, with system shakedown beginning in the second quarter of 1999. Successful demonstration of caster system operation is anticipated to occur during the third quarter and production of a high quality product during the fourth quarter. Although the process is targeted toward reducing the cost of lightweight trucks, buses and autos, consideration is being given to application in the aircraft industry