Spectral early-warning signals for sudden changes in time-dependent flow patterns

Lagrangian coherent sets are known to crucially determine transport and mixing processes in non-autonomous flows. Prominent examples include vortices and jets in geophysical fluid flows. Coherent sets can be identified computationally by a probabilistic transfer-operator-based approach within a set-oriented numerical framework. Here, we study sudden changes in flow patterns that correspond to bifurcations of coherent sets. Significant changes in the spectral properties of a numerical transfer operator are heuristically related to critical events in the phase space of a time-dependent system. The transfer operator approach is applied to different example systems of increasing complexity. In particular, we study the 2002 splitting event of the Antarctic polar vortex

Bilan de la productivité des petits ruminants dans la région de Kaolack de juillet 95 juin 97 et restitution auprès des éleveurs

Menée dans le cadre des activités du Projet de Développement des Espèces à Cycles Courts (PRODEC), cette mission a pour but de fournir une aide à la décision dans le choix de programmes d'amélioration de la productivité animale dans la région de Kaolack (Sénégal). La collecte et l'analyse des données relatives aux troupeaux (taille et structure des troupeaux, paramètres de reproduction, mortalité et taux d'exploitation) montrent que les élevages de l'Agropov ne sont pas semi-intensifs. Les performances zootechniques sont similaires à celles du projet villageois. La différence entre ces deux systèmes ne tient qu'à la production arachidière, à la taille des effectifs des troupeaux et à la spéculation sur les brebis Tabaski. L'intensificatio n de la conduite des troupeaux nécessite une meilleure maîtrise de l'alimentation, le contrôle et la synchronisation des chaleurs et enfin, la conception d'un plan sanitaire d'élevage. L'Agropov peut être le point de départ de l'organisation de la filière ovine au Sénégal. La commission de commercialisation doit trouver des débouchés pour la vente des animaux de boucherie alors que le vétérinaire doit conforter la production en assurant un suivi zootechnique et sanitaire régulie

General insights on obstacles to dog vaccination in Chad on community and institutional level

Domestic dogs are responsible for 95% of all human rabies cases worldwide and continue to be the main reservoir for this fatal virus in African and Asian countries. Interrupting the spread of the disease in the domestic dog population is therefore necessary for long-term, sustainable rabies control. Chad has been recognized as a rabies-endemic country since 1961, but no national control strategy is in place to date and dog vaccination coverage is very low. This qualitative, descriptive study aims to describe the main barriers to dog vaccination on both the community and the institutional level from a socio-anthropological point of view in Chad. The study was embedded in an overall project conducted from 2016 to 2018, to determine rabies burden and vaccine demand in West and Central Africa, funded by GAVI, the vaccine alliance. Data collection was conducted on the occasion of the project's closing workshops with stakeholders organized between August to September 2018 in the four (4) project areas: Logone Occidental, Ouaddai, Hadjer Lamis and Chari Baguirmi. We conducted interviews and focus group discussions (FGD) among veterinary officers and dog owners. Participants were selected purposively based on their place of residence (dog owners) or work place (veterinary officers) and their previous contact with the project through reporting (dog owner) or management (veterinary officers) of a suspect dog rabies case. In each region, one FGD was organized with dog owners, and one FGD with heads of veterinary posts. At the end of the FGDs, a few participants were randomly selected for interviews. In addition, in each region an interview was conducted with the head of the livestock sector, the chief district medical officers and the head of a civil society association. The identified barriers to dog vaccination access are grouped into three main aspects: the economic, the socio-cultural and the institutional level. Economic constraints encountered relate to the cost of the vaccine itself and the expenses for transporting the dogs to the vaccination site. The cultural belief that the vaccine will have an impact on the therapeutic properties of dog meat for consumers (observed in Southern Chad), and the fact that dogs are considered impure animals in Muslim faith, which prohibits handling of dogs, are obstacles identified on the sociocultural level. At the institutional level, the unavailability of vaccines in veterinary services, the lack of communication about the law on dog vaccination, the absence of rabies in the training curricula of veterinary agents, and the lack of intersectoral collaboration limit vaccination coverage. In order to improve vaccination coverage and rabies surveillance with a view to eradicate rabies by 2030, communication strategies that are adapted to the context and that take cultural obstacles into account must be put in place in a synergy of interdisciplinary action. In addition, factors such as affordability, geographical access and availability of dog rabies vaccines needs to be addressed throughout the country. Although our study design did not allow a detailed analysis of obstacles related to socio-economic level, gender and age the broad insights gained can provide general guidance for future interventions in Chad and similar countries

Consumer perception on purchase decision factors and health indicators related to the quality and safety of meat sold in dibiteries in Dakar, Senegal

Accelerated socio-economic and demographic changes have led to the transformation of eating habits in sub-Saharan African cities including Dakar, Senegal. The result is the proliferation of informal fast-food establishments, such as the 'dibiteries' serving braised sheep meat. However, owing to poor hygiene practices, consumption of dibiterie meat poses a public health concern. It was unclear how the dibiterie meat quality and safety were perceived among customers who define their own purchasing social norms. A total of 165 meat consumers were randomly selected and interviewed, from 165 dibiteries sampled by convenience in the Dakar region using a structured questionnaire. Results showed that purchase decisions were guided by trust in the salesperson's expertise, the taste of the product, perceived risk of meat contamination, tenderness, price, the nutritional value, the smell and the colour and freshness of the meat. The perceived quality and safety of dibiterie meat was expressed by the 'organoleptic quality', 'environment and service' and 'price and trust of the product's safety' factors. The majority of consumers (61%) were 'less concerned' about the safety of dibiterie meat, and the acceptable price range of the product was between $5.08 and$7.62. As this food product is gaining popularity in Dakar and the majority of our participating consumers do not show high levels of concern, we suggest stricter standards

Positive Impact of Increases in Condom Use among Female Sex Workers and Clients in a Medium HIV Prevalence Epidemic: Modelling Results from Project SIDA1/2/3 in Cotonou, Benin

Background A comprehensive, HIV prevention programme (Projet Sida1/2/3) was implemented among female sex workers (FSWs) in Cotonou, Benin, in 1993 following which condom use among FSWs increased threefold between 1993 and 2008 while FSW HIV prevalence declined from 53.3% to 30.4%. Objective Estimate the potential impact of the intervention on HIV prevalence/incidence in FSWs, clients and the general population in Cotonou, Benin. Methods and Findings A transmission dynamics model parameterised with setting-specific bio-behavioural data was used within a Bayesian framework to fit the model and simulate HIV transmission in the high and low-risk population of Cotonou and to estimate HIV incidence and infections averted by SIDA1/2/3. Our model results suggest that prior to SIDA1/2/3 commercial sex had contributed directly or indirectly to 93% (84–98%) of all cumulative infections and that the observed decline in FSWs HIV prevalence was more consistent with the self-reported post-intervention increase in condom use by FSWs than a counterfactual assuming no change in condom use after 1993 (CF-1). Compared to the counterfactual (CF-1), the increase in condom use may have prevented 62% (52–71%) of new HIV infections among FSWs between 1993 and 2008 and 33% (20–46%) in the overall population. Conclusions Our analysis provides plausible evidence that the post-intervention increase in condom use during commercial sex significantly reduced HIV prevalence and incidence among FSWs and general population. Sex worker interventions can be effective even in medium HIV prevalence epidemics and need to be sustained over the long-term

Aggravation de l’anémie et polymorphisme de l’haptoglobine au cours de la drépanocytose au Sénégal

La drépanocytose homozygote s’accompagne d’une augmentation de l’hémoglobine (Hb) plasmatique, susceptible d’exposer les hématies à un stress oxydant. L’haptoglobine présente trois phénotypes majeurs (Hp1-1, Hp 2-1 et Hp 2-2) susceptibles de fixer l’hémoglobine extracellulaire avec une efficacité différente. L’objectif de ce travail est de voir si la connaissance du phénotype d’Hp pouvait constituer un élément prédictifde l’anémie sévère. Pour cela, il a été recruté 68 drépanocytaires  homozygotes, âgés de 5 à 31 ans. Pour chaque patient, un témoin de même sexe et de même âge ± 2 ans a été recruté. Le phénotypage de l’Hp a été réalisé par électrophorèse sur gel de polyacrylamide. Les résultats du dosage de l’Hb font ressortir que les taux d’Hb sont significativement différentes chez les patients comparées à celles des témoins (p = 0,001). Lorsque la répartition a été faite en fonction du phénotype d’Hp, une différence statistiquement significative a étéretrouvée entre le phénotype Hp1-1 et le phénotype Hp2-2 (p < 0,001) chez les patients et non chez les témoins. Les résultats de cette étude préliminaire suggéreraient que la connaissance du phénotype d’Hp seraitun facteur prédictif de l’anémie sévère au cours de la drépanocytose.Mots clés : Drépanocytose, anémie, phénotypes d’haptoglobine

Adaptation Actions in Africa: Evidence that Gender Matters

This paper presents the initial data analyses of the CCAFS gender survey implemented in four sites in Africa. Using descriptive statistics we show gender differences in terms of perceptions of climate change, awareness and adoption of climate smart agricultural (CSA) practices, and types and sources of agro-climatic information in the four sites.We find that both men and women are experiencing changes in long-run weather patterns and that they are changing their behaviours in response; albeit relatively minor shifts in existing agricultural practices. For example, the most prevalent changes reported include switching crop varieties, switching types of crops and changing planting dates. As expected, women are less aware of many CSA practices. Encouragingly, this same pattern does not hold when it comes to adoption; in many cases, in East Africa in particular, women, when aware, are more likely than or just as likely as men to adopt CSA practices. In West Africa, overall, the adoption of these practices was much lower. In addition, we see that access to information from different sources varies greatly between men and women and among the sites; however, promisingly, those with access to information report using it to make changes to their agricultural practices. Our findings suggest that targeting women with climate and agricultural information is likely to result in uptake of new agricultural practices for adaptation

Hepatocellular carcinoma associated with pregnancy about 2 cases at the gynecological and obstetrical clinic of the Aristide Le Dantec hospital, Dakar, Senegal

The objective of our study was to report 2 cases of hepatocellular carcinomas associated with pregnancy followed in our structure and to review the literature. Our patients were 30 and 37-year-old multi-gesture females with chronic unattended viral hepatitis B in whom the diagnosis of hepatocellular carcinoma was made in the third trimester of pregnancy at 31 weeks of amenorrhea and 4 days and at 32 weeks of amenorrhea after the incidental finding of tumor hepatomegaly on abdominal-pelvic ultrasound. The main clinical signs were jaundice and hepatomegaly and paraclinical signs were dominated by hepatic cytolysis and anemia in addition to ultrasound images. Follow-up of pregnancies revealed no particularities. A caesarean section was scheduled at 32 weeks of amenorrhea and 32 weeks of amenorrhea and 3 days allowing the birth of two preterm newborns weighing 1210 and 1500 gm with Apgar scores of 8-10/10 and 7-9/10 respectively at the fifth minute. The immediate post-operative follow-up was simple. However, the maternal-fetal prognosis was poor with the death of both patients in a multi-visceral failure table occurring respectively at 6 weeks and 3 weeks after caesarean section. The newborns had died 8 days after birth. Although rare, these two cases challenge any obstetrician to think about liver cancer in pregnant women, especially those with chronic hepatitis B. Ultrasound examination of the liver, or even better, the MRI, which is more efficient, in order to suspect early on a possible liver cancer. Indeed, early diagnosis and a thorough medical approach are essential for the treatment of HCC in pregnant patients