136 research outputs found
Molecular epidemiology of Mansonella perstans on Bioko Island: identification of risk factors, co-infection with malaria and Loa loa and impact in pregnant women
Implementation of an effective and targeted mass drug administration program against filarial worms needs an accurate identification and mapping of the distribution of these parasites. Molecular diagnostic methods like polymerase chain reaction (PCR) based techniques have shown high sensitivity to detect and distinguish parasites at low infection levels and even in people that are amicrofilaremic by microscopy. However, larger scale implementation over time remains a challenge for low-income countries because of logistical complexity and costs, including collection, transportation and preservation of biological samples and running of the analytical tests.
In this study, we aimed to develop and implement a novel molecular based diagnostic approach for monitoring highly neglected filariasis causing parasites in Equatorial Guinea, West Africa. The ENAR protocol is an approach based on the use of nucleic acids (NA) extracted from dried blood retained on used malaria rapid diagnostic test (mRDT). Malaria RDTs used in this work were stored at room temperature for around 18 months before used for molecular analysis and served as reliable source for NA based detection of blood-dwellings pathogens beyond malaria. Our approach of repurposing used mRDTs for filarial parasites detection provides a versatile and cost-effective approach to monitor prevalence, genotype, infection intensity and co-infections of filarial nematodes and other blood borne infectious diseases
Reactive Oxygen Species-Mediated Control of Mitochondrial Biogenesis
Mitochondrial biogenesis is a complex process. It necessitates the contribution of both the nuclear and the mitochondrial genomes and therefore crosstalk between the nucleus and mitochondria. It is now well established that cellular mitochondrial content can vary according to a number of stimuli and physiological states in eukaryotes. The knowledge of the actors and signals regulating the mitochondrial biogenesis is thus of high importance. The cellular redox state has been considered for a long time as a key element in the regulation of various processes. In this paper, we report the involvement of the oxidative stress in the regulation of some actors of mitochondrial biogenesis
Stability of Dissipative Optical Solitons in the 2D Complex Swift-Hohenberg Equation
International audienceThis article deals with stationary localized solutions of the (2D) two-dimensional complex Swift-Hohenberg equation (CSHE). Our approach is based on the semi-analytical method of collective coordinate approach. According to the parameters of the equation and a suitable choice of ansatz, the stationary dissipative solitons of the 2D CSHE equation are mapped. This approach allows to describe the influence of the parameters of the equation on the various physical parameters of the pulse and their dynamics. Finally, the major impact of spectral filtering terms on the dynamic of the solitons is demonstrated
LA VARIABILITE PLUVIOMETRIQUE ET SES IMPACTS SUR LâALIMENTATION EN EAU DES MILIEUX RURAUX DU DEPARTEMENT DE DIMBOKRO (CENTRE-EST DE LA COTE DâIVOIRE)
Rainfall variability in the tropics is a real living reality. In CĂŽte d'Ivoire in general and the Department Dimbokro in particular takes this variability increasingly growing. It is increasingly felt on the forest-savanna contact zone climate and weather conditions are already difficult. This study's main objective is to analyze the rainfall and temperature data over a long period to determine the various trends, breaks in series, then to bring out the consequences for the supply of various rural communities in water department. Clearly it is to characterize the climate event from the analysis of air temperature, relative humidity, changes in rainfall index, the frequency of rainy days and seasons of life rainfall over the period 1955-2000 in order to identify the behavior of seasonal rainfall patterns in the context of climate variability. The analysis of these different climate components including rainfall data, thermal have identified two broad periods separated by a hinge year 1968. Climate variability is manifested by a spatiotemporal dynamics regressive annual rainfall, recession frequency of rainy days in general and especially those of rainfall amounts in excess of 20 mm. Such climatic situation has huge consequences for the availability of hydrology department. The reservoirs in the geological layers will be insufficiently fed, and thereby show their inability to supply boreholes and wells. Once this water recession creates a situation of water stress in the entire department. And 20.57% of the holes drilled in the department have proven nonoperational. It therefore concludes that rainfall variability that knows the department has real impacts on the water supply to rural communities in Dimbokro department
MinĂ©ralogie de la fraction argileuse des sols brunifiĂ©s de Kahankro et Anikro (Toumodi) dans le Centre Sud de la CĂŽte dâIvoire
Dans la perspective dâĂ©lucider les occurrences minĂ©ralogiques des sols brunifiĂ©s de Kahankro et de Anikro (Toumodi), dans la rĂ©gion centre de la CĂŽte dâIvoire, nous nous sommes intĂ©ressĂ©s Ă la fraction argileuse des sols. Cette Ă©tude, dans sa phase technique, a consistĂ© Ă extraire la fraction argileuse des Ă©chantillons de sol prĂ©levĂ©s sur le terrain en sâappuyant sur la mĂ©thode de Hotzapfel. Ces Ă©chantillons, de mĂȘme que ceux du sol total, ont Ă©tĂ© ensuite soumis Ă une analyse aux rayons X sur lame orientĂ©e sĂ©chĂ©e Ă lâair puis, Ă des analyses thermodiffĂ©rentielles et thermopondĂ©rales Ă une tempĂ©rature allant jusquâĂ 1200 °C. Les rĂ©sultats obtenus au bout de cette Ă©tude indiquent que les sols brunifiĂ©s de Kahankro et de Anikro contiennent diffĂ©rents types de minĂ©raux existant en des proportions aussi variĂ©es. Il sâagit des oxydes (quartz, hĂ©matite,ilmĂ©nite et boĂ©hmite) avec une proportion gĂ©nĂ©ralement supĂ©rieure Ă 39%, des minĂ©raux primaires (feldspaths, olivine, dolomite et calcite) ayant une proportion supĂ©rieure Ă 30% et des minĂ©raux argileux (kaolinite, illite et chlorite) qui existent en une proportion gĂ©nĂ©ralement infĂ©rieure Ă 25%. Le phĂ©nomĂšne dâargilation qui prĂ©vaut dans ces sols est la monosiallitisation, vu la prĂ©dominance de minĂ©raux argileux de type 1/1 (kaolinite) sur les autres minĂ©raux argileux. A cette monosiallitisation sâadjoint une bisiallitisation gouvernĂ©e par la richesse des sols en minĂ©raux primaires. Ces sols sont aussi affectĂ©s par un phĂ©nomĂšne de ferrallitisation et les paragenĂšses minĂ©rales de type kaolinite-hĂ©matite permettent de les dĂ©finir comme Ă©tant caractĂ©ristiques dâune couverturedâaltĂ©ration mixte.Mots clĂ©s : Occurrences minĂ©ralogiques, phĂ©nomĂšne dâargilation, ferrallitisation
EVALUATION DES METAUX TRACES, PESTICIDES ET PLASTIFIANTS DANS LES PRODUITS MARAICHERS (GOMBO, CORETE POTAGERE, EPINARD ET AUBERGINE) DANS LAVALLEE DU NIEKI, SUD-EST DE LA COTE DâIVOIRE
A grade assessment study of metal trace metals (Cu, Zn, Cd and Pb), pesticides and plasticizers in market garden crops (Abelmoschus sp, Corchoruus tridens, Basela alba, Solanum aethiopicum) was performed in Niéki Valley in South-East of CÎte d'Ivoire. This study found that trace metals found in the leaves and fruits grown on the different sampling sites are copper (Cu), Zinc (Zn), cadmium (Cd) and Lead (Pb). The Cu was accumulated in the leaves and the fruits. The Cu was accumulated in both the leaves and the fruits. The Cu concentrations in different plants far exceeded thelevels recommendedby the FAO (1 mg.kg-1). The Pb concentrations in different plants were between 106 and 109mg.kg- 1on all sites, far exceeding the thresholds set by the FAO (0.1 mg.kg-1of fresh material). Analyses of various plants showed that most elements are found pesticide family Pyrethroids (Bifenthrin, Deltamethrin and cyhalothrin) and a plasticizerof the phthalate family (1,2Benzenedicarboxylicacid, bis (2- ethylhexyl) ester). Doses of Bifenthrin determined in plants exceeded the acceptable daily intake (ADI) or (0.015 mg.kg-1), except in the case of Abelmoschus sp where these levels remain below the acceptable daily intake
Ătude de la durabilitĂ© Ă©conomique et environnementale de la production de manioc sur ferralsols
Objective: To evaluate the components of the sustainability of cassava cropping systems that rely on alley cropping. Methodology and results: The study consisted to cultivate improved cassava ( Yavo ) / green soybeans ( Mung Bean) / Gliricidia sepium with a basal dressing ( NPK [ 20: 36 : 36] or chicken manure [10 t / ha] ) compared to the traditional system consisting of a local variety of cassava and peanut intercropping on ferralsols. The sum of the new factors of production allowed a significant increase in the food output. In addition to bean production, organic manure and, potentially, fuel wood from G. sepium, the yield of cassava of the introduced variety Yavo was 40 t/ha compared to 13 t/ha in the traditional. The plant architecture of the new systems allowed a good soil cover, thus reducing the frequency of weeding, done traditionally by women. Conversely, workload for men increased. The new system was also economically viable. Conclusion and application of findings: As a whole, the suggested system appears to have a potential to contribute to agronomic, environmental, economic and social sustainability. The new systems could be recommended for the intensification of the cassava crop.Keywords: cassava, Gliricidia sepium, green soya, ferralsol, sustainability
Dry deposition of nitrogen compounds (NO 2 , HNO 3 , NH 3 ), sulfur dioxide and ozone in west and central African ecosystems using the inferential method
Abstract. This work is part of the IDAF program (IGAC-DEBITS-AFRICA) and is based on the long-term monitoring of gas concentrations (1998â2007) established at seven remote sites representative of major African ecosystems. Dry deposition fluxes were estimated by the inferential method using on the one hand surface measurements of gas concentrations (NO2, HNO3, NH3, SO2 and O3) and on the other hand modeled exchange rates. Dry deposition velocities (Vd) were calculated using the big-leaf model of Zhang et al. (2003b). The bidirectional approach is used for NH3 surfaceâatmosphere exchange (Zhang et al., 2010). Surface and meteorological conditions specific to IDAF sites have been used in the models of deposition. The seasonal and annual mean variations of gaseous dry deposition fluxes (NO2, HNO3, NH3, O3 and SO2) are analyzed. Along the latitudinal transect of ecosystems, the annual mean dry deposition fluxes of nitrogen compounds range from â0.4 to â0.8 kg N haâ1 yrâ1 for NO2, from â0.7 to â1.0 kg N haâ1 yrâ1 for HNO3 and from â0.7 to â8.3 kg N haâ1 yrâ1 for NH3 over the study period (1998â2007). The total nitrogen dry deposition flux (NO2+HNO3+NH3) is more important in forests (â10 kg N haâ1 yrâ1) than in wet and dry savannas (â1.6 to â3.9 kg N haâ1 yrâ1). The annual mean dry deposition fluxes of ozone range between â11 and â19 kg haâ1 yrâ1 in dry and wet savannas, and â11 and â13 kg haâ1 yrâ1 in forests. Lowest O3 dry deposition fluxes in forests are correlated to low measured O3 concentrations, lower by a factor of 2â3, compared to other ecosystems. Along the ecosystem transect, the annual mean of SO2 dry deposition fluxes presents low values and a small variability (â0.5 to â1 kg S haâ1 yrâ1). No specific trend in the interannual variability of these gaseous dry deposition fluxes is observed over the study period
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