Economics in West African Irrigated-Rice Production

The main objective of this investigation is to contribute to the ongoing debate on the effects of the West African Economic and Monetary Union (WAEMU), common external tariff (CET) measures on the competitiveness of the irrigated-rice production system in Niger. The policy analysis matrix (PAM) approach was used to evaluate the various policy effects, based on farm-level, postharvest and rice-marketing data, as well as the financial and economic parity prices of different brands of imported-rice. Results from the PAM base-scenario model showed that under the evaluated CET policy irrigated rice production, activities were competitive and private operators had positive financial gains, meaning that private profitability was positive. Moreover, the irrigated-rice production enterprise revealed positive economic profitability for both retailers and wholesalers. Thus, it generated a net positive income for the national economy per unit of land devoted to this activity. One can argue that the irrigated rice system under the CET was generally competitive (positive private profitability) and had a potential for growth (positive economic profitability). Despite its competitiveness and efficiency, the irrigated rice production system still performs below potential because it lacks additional incentives. Some sensitivity analyses were performed with single-factor and simultaneous changes of several factors, which confirmed the necessity of providing further incentives to the system. The research results suggest that greater incentives should be given in terms of improving marketing channels, especially for retail rice marketing in which a great number of women rice traders are active.L'étude vise à contribuer au débat relatif aux effets du tarif extérieur commun (TEC) de l'Union économique et monétaire Ouest-Africaine (UEMOA) sur la compétitivité du riz irrigué au Niger. La Matrice d'analyse des politiques (MAP) a été utilisé pour évaluer les différents effets, sur la base de données relatives à l'exploitation agricole, les activités post-récolte, la commercialisation, ainsi que les prix paritaires financiers et économiques de différents types de riz importés. Avec le TEC, les résultats du modèle de base de la MAP ont montré que la production de riz irrigué a été compétitive et que les acteurs de la chaîne de valeurs ont bénéficié de gains financiers importants (rentabilité financière positive). Par ailleurs, la production de riz irrigué a été une activité économiquement rentable, aussi bien pour les commerçants-détaillants que pour les grossistes. Par conséquent, par unité de terre dévolue à cette activité, le riz irrigué a généré des revenus pour l'économie nationale. Avec le TEC, le système de production de riz irrigué a été généralement compétitif (rentabilité financière positive) et a eu un bon potentiel de croissance économique (rentabilité économique positive). Cependant, malgré, sa compétitivité et son efficacité, la performance du système de production de riz irrigué reste en deçà de son potentiel, du fait du manque d'incitations additionnelles. Des analyses de sensibilité ont été effectuées avec le changement de niveau d'un seul facteur, et de plusieurs facteurs à la fois. Ces analyses confirment la nécessité de mesures incitatives, en termes d'amélioration des circuits de commercialisation, notamment le circuit des détaillants qui implique un nombre assez important de commerçantes.Mots clés: Analyse des politiques, production de riz irrigué, avantage comparatif, rentabilité économique, rentabilité financièr

Monitoring the millennium development goals: the potential role of the INDEPTH Network

The Millennium Declaration, adopted by the United Nations (UN) in 2000, set a series of Millennium Development Goals (MDGs) as priorities for UN member countries, committing governments to realising eight major MDGs and 18 associated targets by 2015. Progress towards these goals is being assessed by tracking a series of 48 technical indicators that have since been unanimously adopted by experts. This concept paper outlines the role member Health and Demographic Surveillance Systems (HDSSs) of the INDEPTH Network could play in monitoring progress towards achieving the MDGs. The unique qualities of the data generated by HDSSs lie in the fact that they provide an opportunity to measure or evaluate interventions longitudinally, through the long-term follow-up of defined populations

The PTEN Phosphatase Controls Intestinal Epithelial Cell Polarity and Barrier Function: Role in Colorectal Cancer Progression

The PTEN phosphatase acts on phosphatidylinositol 3,4,5-triphosphates resulting from phosphatidylinositol 3-kinase (PI3K) activation. PTEN expression has been shown to be decreased in colorectal cancer. Little is known however as to the specific cellular role of PTEN in human intestinal epithelial cells. The aim of this study was to investigate the role of PTEN in human colorectal cancer cells.Caco-2/15, HCT116 and CT26 cells were infected with recombinant lentiviruses expressing a shRNA specifically designed to knock-down PTEN. The impact of PTEN downregulation was analyzed on cell polarization and differentiation, intercellular junction integrity (expression of cell-cell adhesion proteins, barrier function), migration (wound assay), invasion (matrigel-coated transwells) and on tumor and metastasis formation in mice. Electron microscopy analysis showed that lentiviral infection of PTEN shRNA significantly inhibited Caco-2/15 cell polarization, functional differentiation and brush border development. A strong reduction in claudin 1, 3, 4 and 8 was also observed as well as a decrease in transepithelial resistance. Loss of PTEN expression increased the spreading, migration and invasion capacities of colorectal cancer cells in vitro. PTEN downregulation also increased tumor size following subcutaneous injection of colorectal cancer cells in nude mice. Finally, loss of PTEN expression in HCT116 and CT26, but not in Caco-2/15, led to an increase in their metastatic potential following tail-vein injections in mice.Altogether, these results indicate that PTEN controls cellular polarity, establishment of cell-cell junctions, paracellular permeability, migration and tumorigenic/metastatic potential of human colorectal cancer cells

Testing a global standard for quantifying species recovery and assessing conservation impact

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a “Green List of Species” (now the IUCN Green Status of Species). A draft Green Status framework for assessing species’ progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species’ viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species’ recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard

Antibody isotype analysis of malaria-nematode co-infection: problems and solutions associated with cross-reactivity

<p>Abstract</p> <p>Background</p> <p>Antibody isotype responses can be useful as indicators of immune bias during infection. In studies of parasite co-infection however, interpretation of immune bias is complicated by the occurrence of cross-reactive antibodies. To confidently attribute shifts in immune bias to the presence of a co-infecting parasite, we suggest practical approaches to account for antibody cross-reactivity. The potential for cross-reactive antibodies to influence disease outcome is also discussed.</p> <p>Results</p> <p>Utilising two murine models of malaria-helminth co-infection we analysed antibody responses of mice singly- or co-infected with <it>Plasmodium chabaudi chabaudi </it>and <it>Nippostrongylus brasiliensis </it>or <it>Litomosoides sigmodontis</it>. We observed cross-reactive antibody responses that recognised antigens from both pathogens irrespective of whether crude parasite antigen preparations or purified recombinant proteins were used in ELISA. These responses were not apparent in control mice. The relative strength of cross-reactive versus antigen-specific responses was determined by calculating antibody titre. In addition, we analysed antibody binding to periodate-treated antigens, to distinguish responses targeted to protein versus carbohydrate moieties. Periodate treatment affected both antigen-specific and cross-reactive responses. For example, malaria-induced cross-reactive IgG1 responses were found to target the carbohydrate component of the helminth antigen, as they were not detected following periodate treatment. Interestingly, periodate treatment of recombinant malaria antigen Merozoite Surface Protein-1₁₉(MSP-1₁₉) resulted in increased detection of antigen-specific IgG2a responses in malaria-infected mice. This suggests that glycosylation may have been masking protein epitopes and that periodate-treated MSP-1₁₉may more closely reflect the natural non-glycosylated antigen seen during infection.</p> <p>Conclusions</p> <p>In order to utilize antibody isotypes as a measure of immune bias during co-infection studies, it is important to dissect antigen-specific from cross-reactive antibody responses. Calculating antibody titre, rather than using a single dilution of serum, as a measure of the relative strength of the response, largely accomplished this. Elimination of the carbohydrate moiety of an antigen that can often be the target of cross-reactive antibodies also proved useful.</p

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Climate change and desertification in Africa : The Great Green Wall

International audienc

Determinants of agricultural technology adoption under partial population awareness: the case of pigeonpea in Malawi

There is exhaustive literature on technology adoption rates and the relationship between technology adoption and relevant socioeconomic and policy variables. Yet adoption estimates derived from the application of standard techniques such as the probit and tobit yield biased estimates. This paper applies the modern evaluation technique: the counterfactual outcome framework to data from about 400 households in Malawi to assess the patterns of diffusion and adoption of improved pigeonpea varieties and their determinants. We find the sample adoption rate of improved varieties to be 14 % while the potential adoption rate if the improved varieties were widely disseminated is estimated at 41 %. The adoption gap resulting from the incomplete exposure to the improved pigeonpea is 27 %. Moreover, adoption is also found to be high among female-headed households, older farmers and those with access to credit. The findings suggest that for increased adoption, there is need for increased involvement of extension workers is the dissemination of information about improved pigeonpea varieties, a robust pigeonpea seed system to increase seed availability to farmers as well as the need for improved access to credit