Cartographier par télédétection l’occupation du sol et ses changements

Cet article présente une méthode de cartographie par Télédétection de l’occupation du sol et de ses changements à partir du cas de la Sénégambie méridionale. L’approche rétrospective adoptée s’appuie sur la comparaison entre les signatures spectrales dites de « référence » issues des vérités de terrain et celles des classes résultant de la classification multispectrale non supervisée des images prises à des dates antérieures. Le résultat est une cartographie des principales catégories d’occupation du sol à chacune des dates étudiées et de leur évolution dans le temps. Ont ainsi été mis en évidence les principaux changements des paysages forestiers sénégambiens : un important recul des boisements de terre ferme au nord de la région au cours de la dernière décennie et une régénération de la mangrove suite à l’amélioration des conditions pluviométriques.This article presents a method of mapping by remote sensing of land cover and its changes based on the case of Southern Senegambia. The retrospective approach adopted is based on the comparison between the so-called "reference" spectral signatures resulting from ground truths and those of the classes resulting from the unsupervised multispectral classification of images taken at earlier dates. The result is a cartography of the main land cover categories at each of the dates under study and their evolution over time. The main changes in the Senegalese forest landscape were thus highlighted: a significant decline in land afforestation in the north of the region over the last decade and a regeneration of the mangrove following the improvement in rainfall conditions

Profil clinique et évolutif des lésions de la peau et des parties molles chez les diabétiques en 2017 à la salle de pansement du Centre Marc Sankale de Dakar

Introduction: le but de notre étude était de déterminer le profil clinique et évolutif des lésions de la peau et des parties molles des sujets diabétiques suivis à la salle de pansement. Méthodes: il s'agissait d'une étude observationnelle descriptive et analytique menée du 1er janvier au 31 décembre 2017 à la salle de pansement du centre Marc Sankale de Dakar. Notre étude a porté sur les sujets diabétiques ayant consultés à la salle de pansement. Résultats: au total, 37173 actes de soins ont été enregistrés au centre Marc Sankale. Les activés de soins à la salle de pansement représentaient 16418 cas soit une prévalence de 14,16%. L'âge moyen était de 56,6 ± 12 ans et le sex ratio (H/F) de 0,88. Le diabète de type 2 prédominait (78,97%) et la durée moyenne du diabète était de 8,06 ± 7,9 ans. La glycémie capillaire moyenne était de 2,4 ± 1 g/l. La neuropathie diabétique était présente chez 72,33% des cas. Les lésions se situait aux membres dans 93,98% (1185 cas). Les lésions les plus représentatives étaient l'ulcère (46,76%), l'abcès (13,46%), le phlegmon (13,20%), la gangrène (8,41%), l'érysipèle (3,78%), le mal perforant (3,53%), l'intertrigo (3,95%). Les lésions étaient infectieuses (61,41), non infectieuses (33,50%), vasculaires pures (1,57%) et Mixtes (3,70%). Sur les 1189 patients 7,57% avaient présentés une ostéite. Les germes retrouvés étaient des bactéries grams positifs (12,70%), grams négatifs (23,80%). L'amputation était corrélée à la topographie de la lésion (p=0.00), au type de lésion (p=0.000), à l'ancienneté du diabète (p=0,02), au type de diabète (p=0,008), à la présence d'ostéite (p=0,006). L'amputation etait mineur (43,33%), et majeur (37,43%). Nous avons enregistré 70 décès (5,89%). Conclusion: les lésions de la peau et des tissus mous restent dominées par le pied diabétique. La mortalité est non négligeable et le risque d'amputation était statistiquement corrélé à la topographie, au type de lésion, à l'ancienneté et le type de diabète et à l'existence d'ostéite

Techno–ecological synergies of solar energy for global sustainability

The strategic engineering of solar energy technologies—from individual rooftop modules to large solar energy power plants—can confer significant synergistic outcomes across industrial and ecological boundaries. Here, we propose techno–ecological synergy (TES), a framework for engineering mutually beneficial relationships between technological and ecological systems, as an approach to augment the sustainability of solar energy across a diverse suite of recipient environments, including land, food, water, and built-up systems. We provide a conceptual model and framework to describe 16 TESs of solar energy and characterize 20 potential techno–ecological synergistic outcomes of their use. For each solar energy TES, we also introduce metrics and illustrative assessments to demonstrate techno–ecological potential across multiple dimensions. The numerous applications of TES to solar energy technologies are unique among energy systems and represent a powerful frontier in sustainable engineering to minimize unintended consequences on nature associated with a rapid energy transition

High resolution melting: a useful field-deployable method to measure dhfr and dhps drug resistance in both highly and lowly endemic Plasmodium populations

Background: Emergence and spread of drug resistance to every anti-malarial used to date, creates an urgent need for development of sensitive, specifc and feld-deployable molecular tools for detection and surveillance of validated drug resistance markers. Such tools would allow early detection of mutations in resistance loci. The aim of this study was to compare common population signatures and drug resistance marker frequencies between two populations with diferent levels of malaria endemicity and history of anti-malarial drug use: Tanzania and Sénégal. This was accomplished by implementing a high resolution melting assay to study molecular markers of drug resistance as compared to polymerase chain reaction–restriction fragment length polymorphism (PCR/RFLP) methodology. Methods: Fifty blood samples were collected each from a lowly malaria endemic site (Sénégal), and a highly malaria endemic site (Tanzania) from patients presenting with uncomplicated Plasmodium falciparum malaria at clinic. Data representing the DHFR were derived using both PCR–RFLP and HRM assay; while genotyping data representing the DHPS were evaluated in Senegal and Tanzania using HRM. Msp genotyping analysis was used to characterize the multiplicity of infection in both countries. Results: A high prevalence of samples harbouring mutant DHFR alleles was observed in both population using both genotyping techniques. HRM was better able to detect mixed alleles compared to PCR/RFLP for DHFR codon 51 in Tanzania; and only HRM was able to detect mixed infections from Senegal. A high prevalence of mutant alleles in DHFR (codons 51, 59, 108) and DHPS (codon 437) were found among samples from Sénégal while no mutations were observed at DHPS codons 540 and 581, from both countries. Overall, the frequency of samples harbouring either a single DHFR mutation (S108N) or double mutation in DHFR (C59R/S108N) was greater in Sénégal compared to Tanzania Conclusion: Here the results demonstrate that HRM is a rapid, sensitive, and feld-deployable alternative technique to PCR–RFLP genotyping that is useful in populations harbouring more than one parasite genome (polygenomic infections). In this study, a high levels of resistance polymorphisms was observed in both dhfr and dhps, among samples from Tanzania and Sénégal. A routine monitoring by molecular markers can be a way to detect emergence of resistance involving a change in the treatment policy

Provider and User Acceptability of Integrated Treatment for the Control of Malaria and Helminths in Saraya, South-Eastern Senegal.

Integration of vertical programs for the control of malaria, schistosomiasis, and soil-transmitted helminthiasis has been recommended to achieve elimination of malaria and neglected tropical diseases (NTD) by 2030. This qualitative study was conducted within the context of a randomized controlled trial to explore the perceptions and views of parents/caregivers of at-risk children and healthcare providers to determine their acceptability of the integrated malaria-helminth treatment approach. Randomly selected parents/caregivers of children enrolled in the trial, healthcare providers, trial staff, malaria, and NTD program managers were interviewed using purpose-designed topic guides. Transcripts obtained from the interviews were coded and common themes identified using content analysis were triangulated. Fifty-seven study participants comprising 26 parents/caregivers, 10 study children aged ≥ 10 years, 15 trial staff, four healthcare providers, and two managers from the Senegal Ministry of Health were interviewed. Thirty-eight of the participants (66.7%) were males, and their ages ranged from 10 to 65 years. Overall, the integrated malaria-helminth treatment approach was considered acceptable, but the study participants expressed concerns about the taste, smell, and side effects associated with amodiaquine and praziquantel in the combination package. Reluctance to accept the medications was also observed among children aged 10 to 14 years due to peer influence and gender-sensitive cultural beliefs. Addressing concerns about the taste and smell of amodiaquine and praziquantel is needed to optimize the uptake of the integrated treatment program. Also, culturally appropriate strategies need to be put in place to cater for the inclusion of children aged 10 to 14 years in this approach

Genetic diversity of Jatropha curcas L. in Senegal compared with exotic accessions based on microsatellite markers

International audienceSignificant efforts have been undertaken in West Africa to increase biofuel production with the expectation to alleviate the dependency on fossil energies and to reduce rural poverty by diversifying cultivated crops. In this context, Jatropha curcas L., a shrub belonging to Euphorbiaceae family, has gained great interest because of its oil which can be converted to biodiesel. It is also highly adaptable to marginal soils due to its drought-tolerant characteristics. Characterisation of J. curcas germplasm in Senegal could be an important input for its better management and in identifying genotypes that could be used in breeding program. Genetic diversity of 103 accessions including 82 accessions from different agro ecological zones in Senegal and 21 exotic accessions was assessed through 33 microsatellite markers. All the markers gave amplifications at the expected band size. Only one microsatellite marker, JCT17, was polymorphic showing 3 alleles and allows distinguishing 2 accessions from Burkina Faso. The surprisingly low level of genetic variation might be because introduction of J. curcas in Senegal seems to have been done from one or a few origins and the species has not regained genetic diversity since then due to vegetative propagation. Cultivation of J. curcas at large scale may face to vulnerability to pests and require many cautions. They are necessity to widen the genetic base of J. curcas in Senegal via new introductions from its centre of origin

L’hyperthyroïdie de l’enfant au centre hospitalier universitaire de Dakar (Sénégal)

Introduction: L'hyperthyroïdie de l'enfant semble rare et constitue un problème de par son retentissement psychosomatique. L’objectif était defaire le point sur ses aspects épidémiologiques et diagnostiques chez l’enfant à Dakar.Méthodes: Il s'agissait d'une étude multicentrique, descriptive sur 15 ans. Etaient analysés les aspects épidémiologiques, cliniques et étiologiques. Résultats: 239 patients sélectionnés avec une prévalence de 2.4%, un sex ratio (H/F) de 0.36, un âge moyen de 10.8 ans. À l'inclusion, il s'agissait d'un ainé de famille (26.3%), d'une croissance avancée (36.9%), retardée (12.5%), d'une corpulence insuffisante (40.1%). L'étiologie était la maladie de Basedow dans 90.3% avec un facteur psychoaffectif dans 22.1%. Sur le plan clinique, prédominaient la tachycardie (92.4%), le goitre (91.1%), l'exophtalmie (81.8%), l'amaigrissement (69.8%) avec cependant une énurésie (30.2%) et des manifestations psychiques (3.1%). Les manifestations cardiovasculaires et cutanées étaient positivement associées avec l'âge (p < 0.05). Le goitre était associé au sexe féminin (p = 0.005), aux signes cardiovasculaires (p = 0.02), neuropsychiques (p = 0.03), cutanées (p = 0.03) et à la diarrhée (p = 0.03). La T4 libre était corrélée à l'âge (p = 0.007), la diarrhée (p = 0.021), l'anxiété (p = 0.024), la fréquence cardiaque (p = 0.00) et la maladie de Basedow (p = 0.04). Plus le goitre était volumineux, plus était augmentée la T4 libre (p = 0.007). Conclusion: L'hyperthyroïdie de l'enfant se différencie de celle de l'adulte par les facteurs d'induction, les perturbations sur la croissance et l'énurésie. L’âge et le sexe semble favoriser le tableau clinique de thyrotoxicose et les signes associés.Mots clés: Hyperthyroïdie, enfant, Sénéga