Staphylococcus aureus (S. aureus) is a bacterial pathogen for humans and animals. These bacteria can resist against many antibiotics and this resistance constitute an alarming worldwide human health threat due to the ...Staphylococcus aureus (S. aureus) is a bacterial pathogen for humans and animals. These bacteria can resist against many antibiotics and this resistance constitute an alarming worldwide human health threat due to the morbidity and mortality. Phage therapy is one of the alternative treatments. The aim of this study was to isolate and characterize lytic phages of S. aureus from different wastewater sources in Bobo-Dioulasso, Burkina Faso. Eight strains of S. aureus were isolated from different clinical samples and were used to isolate phages. The isolation and host range of phages were done by the spot test. Phages were purified by the double-layer method. Similar phages after the determination of the host range were characterized using restriction enzymes. A total of 27 phages were obtained after isolation and purification. Nine of the 27 isolates reported a broad host range (≥67%). The results of enzymatic digestion allowed to consider that all phage isolates that presented the same host range and the same genetic fingerprint are the same phage strain;whereas phages that presented the same host range and different genetic fingerprints are different phage strains. Thus, a total of 15 distinct phages isolates specific to S. aureus were characterized. This study highlighted the abundance and lytic capacity of phages isolated from wastewater from Bobo-Dioulasso’s environment against clinical strains of S. aureus. The lytic capacity of these Staphyphages could be an effective alternative tool to combat bacteria multi-resistance.展开更多
BACKGROUND In endemic areas,vertical transmission of hepatitis B virus(HBV)remains a major source of the global reservoir of infected people.Eliminating mother-to-child transmission(MTCT)of HBV is at the heart of Worl...BACKGROUND In endemic areas,vertical transmission of hepatitis B virus(HBV)remains a major source of the global reservoir of infected people.Eliminating mother-to-child transmission(MTCT)of HBV is at the heart of World Health Organization’s goal of reducing the incidence of HBV in children to less than 0.1%by 2030.Universal screening for hepatitis B during pregnancy and neonatal vaccination are the main preventive measures.AIM To evaluate the efficacy of HBV vaccination combined with one dose of immunoglobulin in children born to hepatitis B surface antigen(HBsAg)-positive mothers in Djibouti city.METHODS We conducted a study in a prospective cohort of HBsAg-positive pregnant women and their infants.The study ran from January 2021 to May 2022,and infants were followed up to 7 mo of age.HBV serological markers and viral load in pregnant women were measured using aVidas microparticle enzyme-linked immunosorbent assay(Biomérieux,Paris,France)and the automated Amplix platform(Biosynex,Strasbourg,France).All infants received hepatitis B immunoglobulin and were vaccinated against HBV at birth.These infants were closely monitored to assess their seroprotective response and for failure of immunoprophylaxis.Simple logistic regression was also used to identify risk factors associated with immunoprophylaxis failure and poor vaccine response.All statistical analyses were performed with version 4.0.1 of the R software.RESULTS Of the 50 pregnant women recruited,the median age was 31 years,ranging from 18 years to 41 years.The MTCT rate in this cohort was 4%(2/50)in HBsAg-positive women and 67%(2/3)in hepatitis B e antigen-positive women with a viral load>200000 IU/mL.Of the 48 infants who did not fail immunoprophylaxis,8(16%)became poor responders(anti-HB<100 mIU/mL)after HBV vaccination and hepatitis B immunoglobulin,while 40(84%)infants achieved a good level of seroprotection(anti-HB>100 mIU/mL).Factors associated with this failure of immunoprophylaxis were maternal HBV DNA levels(>200000 IU/mL)and hepatitis B e antigen-positive status(odds ratio=158,95%confidence interval:5.05-4958,P<0.01).Birth weight<2500 g was associated with a poor immune response to vaccination(odds ratio=34,95%confidence interval:3.01-383.86,P<0.01).CONCLUSION Despite a failure rate of immunoprophylaxis higher than the World Health Organization target,this study showed that the combination of immunoglobulin and HBV vaccine was effective in preventing MTCT of HBV.Therefore,further studies are needed to better understand the challenges associated with immunoprophylaxis failure in infants in Djibouti city.展开更多
Introduction: Malaria control needs the development of complementary and/or alternative strategies such as biological controls. Despite, malaria’s current control efforts, the spread and the emergence of insecticide ...Introduction: Malaria control needs the development of complementary and/or alternative strategies such as biological controls. Despite, malaria’s current control efforts, the spread and the emergence of insecticide resistance in vectors undermine the fight against vectors. Endonsymbiotic fungi can be a good candidate to include in the existence of Arsenal. However, we know little about endosymbiotic fungi transmission and its impact on malaria transmission. In this paper, the authors aimed to investigate Microsporidia sp MB transgenerational and sexual autodissemination and malaria parasites within Anopheline mosquitoes. Methods: An entomology survey was conducted in Burkina Faso for one year (June 2020 to June 2021) using the Residual Fauna Capture method. Infection rates in collected females, sexual autodissemination of Microsporidia sp MB in both Microsporidia sp MB negative females and Microsporidia sp MB negative males through mating, transgenerational prevalence from parents to offsprings and the correlation between Microsporidia sp MB and Plasmodium falciparum were investigated. Results: Results show Microsporidia sp MB infection in An. gambaie s.l in Burkina Faso. The prevalence was significantly higher (21.78%) in An. coluzzii than An. gambiae s.s (16.89%) (p-value = 0.03). Sexual auto-dissemination of Microsporidia sp MB in Microsporidia sp MB uninfected females was significantly 3-fold lower than those in Microsporidia sp MB uninfected males (9.23% and 33.33%, p-value = 0.03) during mating for An. coluzzii lines. Microsporidia sp MB prevalence was significantly higher through mosquitos’ generations in An. gambaie s.s than An. coluzzii (30.23% vs 26.41%, p-value Microsporidia sp MB and Plasmodium infection rate with 73% of Microsporidia sp MB positive mosquitoes which were negative at Plasmodium infection (p-value Conclusions: Our findings pave the road to developing new malaria control technologies by making Microsporidia sp MB-positive males sexually competitive with wild males to spread the fungus to wild female mosquitoes.展开更多
This article presents a three-dimensional analysis of the impact of the angle of incidence of the magnetic field intensity on the electrical performance (series resistance, shunt resistance) of a bifacial polycrystall...This article presents a three-dimensional analysis of the impact of the angle of incidence of the magnetic field intensity on the electrical performance (series resistance, shunt resistance) of a bifacial polycrystalline silicon solar cell. The cell is illuminated simultaneously from both sides. The continuity equation for the excess minority carriers is solved at the emitter and at the depth of the base respectively. The analytical expressions for photocurrent density, photovoltage, series resistance and shunt resistance were deduced. Using these expressions, the values of the series and shunt resistances were extracted for different values of the angle of incidence of the magnetic field intensity. The study shows that as the angle of incidence increases, the slopes of the minority carrier density for the two modes of operation of the solar cell decrease. This is explained by a drop in the accumulation of carriers in the area close to the junction due to the fact that the Lorentz force is unable to drive the carriers towards the lateral surfaces due to the weak action of the magnetic field, which tends to cancel out as the incidence angle increases, and consequently a drop in the open circuit photovoltage. This, in turn, reduces the Lorentz force. These results predict that the p-n junction of the solar cell will not heat up. The study also showed a decrease in series resistance as the incidence angle of the magnetic field intensity increased from 0 rad to π/2 rad and an increase in shunt resistance as the incidence angle increased. His behaviour of the electrical parameters when the angle of incidence of the field from 0 rad to π/2 rad shows that the decreasing magnetic field vector tends to be collinear with the electron trajectory. This allows them to cross the junction and participate in the external current. The best orientation for the Lorentz force is zero, in which case the carriers can move easily towards the junction.展开更多
Activated carbons (ACs) calcined at 400˚C, 500˚C, and 600˚C (AC-400, AC-500, and AC-600) were prepared using palm nut shells from Gabon as raw material and zinc chloride (ZnCl2) as a chemical activating agent. Prepare...Activated carbons (ACs) calcined at 400˚C, 500˚C, and 600˚C (AC-400, AC-500, and AC-600) were prepared using palm nut shells from Gabon as raw material and zinc chloride (ZnCl2) as a chemical activating agent. Prepared ACs were characterized by physisorption of nitrogen (N2), determination of diode and methylene blue numbers for studies of porosity and by quantification and determination of surface functional groups and pH at point of zero charge (pHpzc) respectively, for studies of chemical properties of prepared ACs. Then, effects of calcination temperature (Tcal) on porosity and chemical properties of prepared ACs were studied. The results obtained showed that when the calcination temperature increases from 500˚C to 600˚C, the porosity and chemical properties of prepared ACs are modified. Indeed, the methylene blue and iodine numbers determined for activated carbons AC-400 (460 and 7.94 mg·g−1, respectively) and AC-500 (680 and 8.90 mg·g−1, respectively) are higher than those obtained for AC-600 (360 and 5.75 mg·g−1, respectively). Compared to the AC-500 adsorbent, specific surface areas (SBET) and microporous volume losses for AC-600 were estimated to 44.7% and 45.8%, respectively. Moreover, in our experimental conditions, the effect of Tcal on the quantities of acidic and basic functional groups on the surface of the ACs appears negligible. In addition, results of the pHpzc of prepared ACs showed that as Tcal increases, the pH of the adsorbents increases and tends towards neutrality. Indeed, a stronger acidity was determined on AC-400 (pHpzc = 5.60) compared to those on AC-500 and AC-600 (pHpzc = 6.85 and 6.70, respectively). Also according to the results of porosity and chemical characterizations, adsorption being a surface phenomenon, 500˚C appears to be the optimal calcination temperature for the preparation of activated carbons from palm nut shells in our experimental conditions.展开更多
Methane generation in landfills and its inadequate management represent the major avoidable source of anthropogenic methane today. This paper models methane production and the potential resources expected (electrical ...Methane generation in landfills and its inadequate management represent the major avoidable source of anthropogenic methane today. This paper models methane production and the potential resources expected (electrical energy production and potential carbon credits from avoided CH4 emissions) from its proper management in a municipal solid waste landfill located in Ouagadougou, Burkina Faso. The modeling was carried out using two first-order decay (FOD) models (LandGEM V3.02 and SWANA) using parameters evaluated on the basis of the characteristics of the waste admitted to the landfill and weather data for the site. At the same time, production data have been collected since 2016 in order to compare them with the model results. The results obtained from these models were compared to experimental one. For the simulation of methane production, the SWANA model showed better consistency with experimental data, with a coefficient of determination (R²) of 0.59 compared with the LandGEM model, which obtained a coefficient of 0.006. Thus, despite the low correlation values linked to the poor consistency of experimental data, the SWANA model models methane production much better than the LandGEM model. Thus, despite the low correlation values linked to the poor consistency of the experimental data, the SWANA model models methane production much better than the LandGEM V3.02 model. It was noted that the poor consistency of the experimental data justifies these low coefficients, and that they can be improved in the future thanks to ongoing in situ measurements. According to the SWANA model prediction, in 27 years of operation a biogas plant with 33% electrical efficiency using biogas from the Polesgo landfill would avoid 1,340 GgCO2e. Also, the evaluation of revenues due to electricity and carbon credit gave a total revenue derived from methane production of US$27.38 million at a cost of US$10.5/tonne CO2e.展开更多
Background: Breast cancer is the dominant cancer in women in both developed and developing countries. The objective of this study was to assess the knowledge, attitudes, practices and factors associated with early bre...Background: Breast cancer is the dominant cancer in women in both developed and developing countries. The objective of this study was to assess the knowledge, attitudes, practices and factors associated with early breast cancer screening among women in the Municipality of Abomey-Calavi in Benin. Methods: This was a cross-sectional, descriptive, analytical study with prospective data collection from October 1 to 8, 2018, involving 1740 women in the Municipality of Abomey-Calavi, aged 18 years or older and selected by WHO four-stage random cluster sampling. Consenting women who were mentally competent, 18 years of age or older at the time of the survey, and residing continuously in the Municipality of Abomey-Calavi for the last six months prior to the survey were included. On the other hand, women who belonged to a breast cancer prevention service, women in whom secondary screening was noted, or non-consenting women were not included. The initial minimum size was estimated by the Schwartz formula with a cluster effect of k = 2. Information was collected by questionnaire survey, entered with Epidata 3.1. Fr and analyzed with R Studio 3.5.1. software. Results: The mean age of the women surveyed was 32.0 ± 11.5 years with a range of 18 and 71 years. Regarding knowledge, the clinical manifestation known by the majority of women was the presence of a nodule (68.50%). In the series, 1308 (75.17%) declared having heard about breast cancer once before, either on the radio, television or from friends and 726 (55.50%) had heard about breast cancer screening. Five hundred and twelve (70.52%) of the 726 who had heard of breast cancer said they knew that breast cancer could be screened earlier. Breast self-examination was the most cited screening method (67.58%). The disease is of natural origin according to 37.84% of them. Regarding attitudes and practices, the prevalence of early breast cancer screening was 12.93%, of which 11.67% declared that they had checked themselves to know whether they were carriers of the disease or not. The main means of the early screening used was breast self-examination (85.78%). Factors associated with early breast cancer screening found in multivariate analysis were age (≤50 years), education level (increasingly higher), marital status (married/coupled), place of residence (downtown), and socioeconomic level (average/high). Conclusion: The frequency of early breast cancer screening among women is still low in the municipality of Abomey-Calavi, although they have a good knowledge of the disease. This raises the need to strengthen awareness of early breast cancer screening.展开更多
The study evaluated the growth performance and carcass quality of COBB500 broilers fed two experimental rations incorporating feed and mango fine ED<sub>10</sub> for a batch of 83 birds, ED<sub>20<...The study evaluated the growth performance and carcass quality of COBB500 broilers fed two experimental rations incorporating feed and mango fine ED<sub>10</sub> for a batch of 83 birds, ED<sub>20</sub> (batch of 83 birds) in comparison with a commercial control ration CCD (84 birds). For this purpose, 250 day-old chicks of this breed were purchased in Korhogo and transported to Tengréla in Ivory Coast for rearing. The results show that substituting mango provender ans and mango seed flour for maize resulted in rations with costs per kgMS of 215.35FCFA, 2016.93FCFA and 320FCFA for the ED<sub>10</sub>, ED<sub>20</sub> and CCD rations respectively. The production costs per kg of chicken (FCPkgLW) of the CCD ration were significantly higher than those of the ED10 and ED<sub>20</sub> (p 0.05). ADGs were significantly different and decreasing from CCD, ED<sub>20</sub> to ED<sub>10</sub> (p 0.05). Average weights at 42nd day for ED<sub>20</sub> and CCD were homogeneous (p > 0.05) and significantly higher than for ED<sub>10</sub> (p 0.05). By day 49th the average weight of ED<sub>20</sub> had reached and exceeded that of CCD by day 42nd. PSLW, HCW and CCW were significantly different and decreasing from CCW, ED<sub>20</sub> to ED<sub>10</sub> (p 0.05). Average hot (HCY) and cooled (CCY) carcass yields of ED<sub>20</sub> and CCD rations were comparable (p > 0.05) and significantly higher than those of ED<sub>10</sub> ration (p = 0.009) and 0.003). Average drumstick and neck weights were significantly higher and lower for CCD, ED<sub>20</sub> and ED<sub>10</sub> (p 0.05). For all other parts of the cut, the average weights of the CCD ration were significantly higher (p 0.05) than those of the ED<sub>20</sub> and ED<sub>10</sub> rations, which were homogeneous (p 0.05). The incorporation of mango provender and mango seed flour in broiler rations offers the prospect of reduced production costs, less competition between man and animals over cereals, and lean meat production that is more appreciated than that of chickens fed conventional feed. As it stands, the ED<sub>20</sub> ration can be recommended as a growth diet for broilers. It would be necessary to determine the levels of anti-nutritional substances in mango feeds and to assess the in vivo digestibility of mango ingredients and the diets incorporating them.展开更多
Civil engineering works require the selection of soil-type materials and the assessment of their geomechanical characteristics. However, the lack of relevant geotechnical mapping to facilitate the prediction of granul...Civil engineering works require the selection of soil-type materials and the assessment of their geomechanical characteristics. However, the lack of relevant geotechnical mapping to facilitate the prediction of granular material zones for civil engineering works in Benin means that very costly and sometimes inconclusive prospecting has to be undertaken for each project. The aim of this study is to contribute to the availability of geotechnical mapping in Benin. For this purpose, and in order to capitalize on the data, the proposed methodological approach is based on the systematic and controlled recording of data produced by laboratories during geotechnical and geological surveys for road construction projects. To this end, a web platform called ROAD MAT has been designed for data recording. This platform has been tested using data from test results from sixteen boreholes drilled in the Mono department. These results show a predominance of soil class G2 and CBR class P2. The database is steadily expanding, and its use by stakeholders will make it possible to collect and centralize vital data to define benchmarks for greater control of geotechnical risks. This work therefore constitutes a blueprint for the development of geotechnical mapping in Benin.展开更多
Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their perform...Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their performance is exploited with lossy compression techniques for images and videos generally using a mixed approach. To achieve our intended objective, which is to study the performance of lossless compression methods, we first carried out a literature review, a summary of which enabled us to select the most relevant, namely the following: arithmetic coding, LZW, Tunstall’s algorithm, RLE, BWT, Huffman coding and Shannon-Fano. Secondly, we designed a purposive text dataset with a repeating pattern in order to test the behavior and effectiveness of the selected compression techniques. Thirdly, we designed the compression algorithms and developed the programs (scripts) in Matlab in order to test their performance. Finally, following the tests conducted on relevant data that we constructed according to a deliberate model, the results show that these methods presented in order of performance are very satisfactory:- LZW- Arithmetic coding- Tunstall algorithm- BWT + RLELikewise, it appears that on the one hand, the performance of certain techniques relative to others is strongly linked to the sequencing and/or recurrence of symbols that make up the message, and on the other hand, to the cumulative time of encoding and decoding.展开更多
Candida auris since it discovery in 2009 is becoming a severe threat to human health due to its very quickly spread, its worldwide high resistance to systemic antifungal drugs. In resource-constrained settings where s...Candida auris since it discovery in 2009 is becoming a severe threat to human health due to its very quickly spread, its worldwide high resistance to systemic antifungal drugs. In resource-constrained settings where several conditions are met for its emergence and spread, this worrisome fungus could cause large hospital and/or community-based outbreaks. This review aimed to summarize the available data on C. auris in Africa focusing on its epidemiology and antifungal resistance profile. Major databases were searched for articles on the epidemiology and antifungal resistance profile of C. auris in Africa. Out of 2,521 articles identified 22 met the inclusion criteria. In Africa, nearly 89% of African countries have no published data on C. auris. The prevalence of C. auris in Africa was 8.74%. The case fatality rate of C. auris infection in Africa was 39.46%. The main C. auris risk factors reported in Africa were cardiovascular disease, renal failure, diabetes, HIV, recent intake of antimicrobial drugs, ICU admissions, surgery, hemodialysis, parenteral nutrition and indwelling devices. Four phylogenetic clades were reported in Africa, namely clades I, II, III and IV. Candida auris showed a pan-African very high resistance rate to fluconazole, moderate resistance to amphotericin B, and high susceptibility to echinocandins. Finally, C. auris clade-specific mutations were observed within the ERG2, ERG3, ERG9, ERG11, FKS1, TAC1b and MRR1 genes in Africa. This systematic review showed the presence of C. auris in the African continent and a worrying unavailability of data on this resilient fungus in most African countries.展开更多
This work investigated the removal, kinetics and thermodynamics of iron(II) ions (Fe(II)) by adsorption in static and dynamic conditions in aqueous media on activated carbons (AC-i30min, AC-i1h, and AC-i24h), prepared...This work investigated the removal, kinetics and thermodynamics of iron(II) ions (Fe(II)) by adsorption in static and dynamic conditions in aqueous media on activated carbons (AC-i30min, AC-i1h, and AC-i24h), prepared from palm nut shells collected in the city of Franceville to Gabon, using potassium hydroxide (KOH) as the activating agent. Results on the elimination of Fe(II) in static and dynamic adsorption on prepared activated carbons (ACs) showed that the AC-i24h adsorbent has the best Fe(II) adsorption capacities at saturation (Qsat). The Qsat obtained on AC-i24h in static and dynamic conditions (17.87 and 10.38 mg/g, respectively) were higher than those of AC-i30min (13.89 and 5.54 mg/g respectively) and AC-i1h (14.92 and 8.64 mg/g respectively). Moreover, the static adsorption was more effective in the removal of Fe(II) ions in aqueous media in our experimental conditions. The percentage removal (%E) of Fe(II) obtained on prepared activated carbons in static conditions was better than those obtained in dynamic conditions, especially on AC-i24h, where the %E was 89.27% in static and 61.56% in dynamic. In kinetics, results showed that the pseudo-second-order kinetic model best described the adsorption mechanisms of Fe(II) on prepared activated carbons in static adsorption, with mainly of chemisorption on the solid surfaces. However, in dynamic conditions, the pseudo-first-order kinetic model was more suitable. In addition to the weak interactions between Fe(II) and the activated carbon surfaces, strong interactions (chemisorption) were also observed. Also, thermodynamic data obtained on AC-i24h in static adsorption indicated that the adsorption of Fe(II) was spontaneous and increased with temperature (ΔG˚ H˚ = 503.54 KJ/mol).展开更多
With the aim of enhancing the value of local building materials, the subject of this paper is a thermophysical study of natural Chadian clay from the eastern region of Chad, “Abeche”. Samples were taken from a brick...With the aim of enhancing the value of local building materials, the subject of this paper is a thermophysical study of natural Chadian clay from the eastern region of Chad, “Abeche”. Samples were taken from a brickwork in Abeche from a depth of 1 m, then using a clay brick-making press, 4 × 5 × 8 cm3 clay test tubes were made with 2%, 4%, 6% and 8% cow dung, and a 100% clay sample was used as a control. These samples underwent thermophysical characterization using the hot-wire method with a hot-plane option, yielding results that could improve thermophysical performance. The thermal conductivity of the test sample is in the order of 0.715 to 0.420 W/m. K, at 8% for cow dung, so the addition of cow dung as a percentage in the clay matrix enabled us to obtain various satisfactory thermal parameters.展开更多
The development of artificial intelligence (AI), particularly deep learning, has made it possible to accelerate and improve the processing of data collected in different fields (commerce, medicine, surveillance or sec...The development of artificial intelligence (AI), particularly deep learning, has made it possible to accelerate and improve the processing of data collected in different fields (commerce, medicine, surveillance or security, agriculture, etc.). Most related works use open source consistent image databases. This is the case for ImageNet reference data such as coco data, IP102, CIFAR-10, STL-10 and many others with variability representatives. The consistency of its images contributes to the spectacular results observed in its fields with deep learning. The application of deep learning which is making its debut in geology does not, to our knowledge, include a database of microscopic images of thin sections of open source rock minerals. In this paper, we evaluate three optimizers under the AlexNet architecture to check whether our acquired mineral images have object features or patterns that are clear and distinct to be extracted by a neural network. These are thin sections of magmatic rocks (biotite and 2-mica granite, granodiorite, simple granite, dolerite, charnokite and gabbros, etc.) which served as support. We use two hyper-parameters: the number of epochs to perform complete rounds on the entire data set and the “learning rate” to indicate how quickly the weights in the network will be modified during optimization. Using Transfer Learning, the three (3) optimizers all based on the gradient descent methods of Stochastic Momentum Gradient Descent (sgdm), Root Mean Square Propagation (RMSprop) algorithm and Adaptive Estimation of moment (Adam) achieved better performance. The recorded results indicate that the Momentum optimizer achieved the best scores respectively of 96.2% with a learning step set to 10−3 for a fixed choice of 350 epochs during this variation and 96, 7% over 300 epochs for the same value of the learning step. This performance is expected to provide excellent insight into image quality for future studies. Then they participate in the development of an intelligent system for the identification and classification of minerals, seven (7) in total (quartz, biotite, amphibole, plagioclase, feldspar, muscovite, pyroxene) and rocks.展开更多
Land use dynamics is a prerequisite for identifying natural resource management constraints,the evolution of agrarian practices and population growth.The objective of this research is to improve knowledge of the dynam...Land use dynamics is a prerequisite for identifying natural resource management constraints,the evolution of agrarian practices and population growth.The objective of this research is to improve knowledge of the dynamics of agricultural land use in the dryland(Cinzana)and cotton(Kléla)areas of Mali.The methodology used consisted of planimetric data collection and diachronic analysis using Landsat TM(Thematic Mapper)satellite images from 2000 and OLI(Operational Land Image)from 2020.Degradation and deforestation rates of natural formations were calculated on the one hand,and on the other hand,the speed and intensity of changes were evaluated using the Pontius matrix22 and intensity analysis programs from the transition matrix.The results of the diachronic analysis revealed a clear increase in the area of anthropogenic formations,especially fields and fallow land,at the expense of natural formations.In Cinzana,this was reflected in an overall increase in the area of anthropogenic formations of 45%(i.e.,2.30%per year)and an overall reduction of 45.15%(2.26%per year)in the area of natural units.In Kléla,there was an overall increase of 131%(i.e.,6.54%per year)in the area of fields and fallow land to the detriment of natural formations,which underwent a reduction of 95%(i.e.,4.76%per year)between 2000 and 2020.Definitely,the evolution of landscape units in the research area between 2000 and 2020 points to excessive anthropization of natural formations,which could compromise the sustainability of these formations,with a risk to ecosystem services and agricultural productivity lost.The study recommends the use of agro-ecological practices,and the facilitation of access to agricultural technologies and support services with a view to agricultural intensification.Policy measures to promote an agro-ecological transition should be encouraged.展开更多
This study highlighted the physical transformation that agri-food products undergo during their drying. This transformation enormously affects the customer’s choice and the profit margin of the dried product promoter...This study highlighted the physical transformation that agri-food products undergo during their drying. This transformation enormously affects the customer’s choice and the profit margin of the dried product promoter. The example of the experimental study of the potato reveals that the product continually changes its dimensions during its drying. The more the product loses its water, the more the dimensions decrease. The results initially showed that the water parameters such as mass or water content decrease according to the drying principle. The dimensions length L., width l and thickness e. decrease following a linear trend whose mathematical equations which describe them are determined using the office tool, excel. This trend has repercussions on the surface and volume parameters which in turn decreases almost linearly with the product’s water content. Note that the coefficient R2 is not always acceptable, confirming the complex nature of the behavior of organic products.展开更多
Invasive candidiasis (IC) is an emerging opportunistic fungal infection associated with high mortality among hospitalized patients. Although the epidemiology of IC is progressively changing worldwide, the trend in Afr...Invasive candidiasis (IC) is an emerging opportunistic fungal infection associated with high mortality among hospitalized patients. Although the epidemiology of IC is progressively changing worldwide, the trend in Africa still needs to be established. This review aimed to evaluate the epidemiology of IC in Western region of Africa. A comprehensive literature search was performed on major electronic databases to identify relevant articles. DerSimonian and Laird random-effects model was used to pool overall prevalence and estimated incidence data. We identified 1975 articles, among which 23 met our inclusion criteria for the systematic review. Available data showed that only 50% (8/16) of West African countries were reported data on IC and only 25% reported at least one laboratory confirmed IC case. The global prevalence of candidemia and non-candidemic deep-seated candidiasis were 0.35% [95% CI 0.23;0.47] and 0.32% [95% CI 0.00;2.03], respectively. Among clinical IC cases, only 5.21% were reported before 2010, while 50.08% were reported in the past 5 years. The pooled estimated incidence was 5.55/100,000 [95% CI 5.46;5.64] and 1.15/100,000 [95% CI 1.11;1.19, 95% CI]/inhabitants for candidemia, and Candida peritonitis, respectively. The case fatality rate was 57.58%. Low gestational age, exposure to broad-spectrum antibiotics and invasive procedures were associated with a higher risk of IC in newborn patients. Candida albicans (32.98%) was the most common causative species of IC followed by C. tropicalis (11.34%) and C. parapsilosis (6.19%). This study showed the scarcity of IC data in western region of Africa and the existence of undiagnosed IC cases.展开更多
A platform named EMECS based on embedded Ethernet control system is implemented.A PC running Fedora 6(Linux2.6)works as a central controller.A kit running Linux 2.4 based on Samsung2410A(ARM920t core)works as a remote...A platform named EMECS based on embedded Ethernet control system is implemented.A PC running Fedora 6(Linux2.6)works as a central controller.A kit running Linux 2.4 based on Samsung2410A(ARM920t core)works as a remote controller and a DC motor(ESCA P28HSL18-219/204)made by Portescap Company works as a plant.Firstly,system modeling is presented by analyzing the characteristics of Ethernet and the plant,based on a proposed delay measurement method.Secondly,implementation of the system including program and hardware is described in detail.And then the delay is measured and the control results of the system are tested in three cases with different network loads as well.The platform is proved to have flexibility of running different control algorithms and extensibility of adding nodes.Experiment results demonstrate the validity of the system.展开更多
In this study, the material is okra, a cucurbitaceous largely consumed in West Africa and South Asia. The influence of the external air parameters on food drying with different size, maturity, shape of the material is...In this study, the material is okra, a cucurbitaceous largely consumed in West Africa and South Asia. The influence of the external air parameters on food drying with different size, maturity, shape of the material is considered by convective drying. So, the okra was cut in several parts according to its three characteristic zones, the basis, the middle of the okra and the extremity because the three parts of the vegetable have not the same resistances in transfers by convective drying. The maturity of the okra also has an influence. The okra dries faster in its younger or older age. Okra dries slowly when its maturity is convenient to be consumed. The drying duration of okra with the age of 1, 2, 3, 4 and 5 days is respectively 580, 780, 990, 1200 and 850 min. When we consider the three (matters) constituent of the okra: the skin, the seeds and the central material, the central matter dries faster. The diffusion coefficient was identified in all cases in order to compare the influence of those intrinsic properties of that food.展开更多
To the Editor:Accessory gallbladders(AG)are rare and their management are usually challenging.These variations are related with an abnormal division of the bile ducts precursors between the 5th and the 12th week of pr...To the Editor:Accessory gallbladders(AG)are rare and their management are usually challenging.These variations are related with an abnormal division of the bile ducts precursors between the 5th and the 12th week of pregnancy.Harlaftis et al.[1]proposed an anatomical classification of these variations based on the embryologic abnormalities described.In type 1 both gallbladders are connected to the common bile duct at the same location.In type 2 the AG can reach either the common bile duct(ductular type)or an intrahepatic biliary duct(trabecular type).In type 3,three gallbladders are present.展开更多
文摘Staphylococcus aureus (S. aureus) is a bacterial pathogen for humans and animals. These bacteria can resist against many antibiotics and this resistance constitute an alarming worldwide human health threat due to the morbidity and mortality. Phage therapy is one of the alternative treatments. The aim of this study was to isolate and characterize lytic phages of S. aureus from different wastewater sources in Bobo-Dioulasso, Burkina Faso. Eight strains of S. aureus were isolated from different clinical samples and were used to isolate phages. The isolation and host range of phages were done by the spot test. Phages were purified by the double-layer method. Similar phages after the determination of the host range were characterized using restriction enzymes. A total of 27 phages were obtained after isolation and purification. Nine of the 27 isolates reported a broad host range (≥67%). The results of enzymatic digestion allowed to consider that all phage isolates that presented the same host range and the same genetic fingerprint are the same phage strain;whereas phages that presented the same host range and different genetic fingerprints are different phage strains. Thus, a total of 15 distinct phages isolates specific to S. aureus were characterized. This study highlighted the abundance and lytic capacity of phages isolated from wastewater from Bobo-Dioulasso’s environment against clinical strains of S. aureus. The lytic capacity of these Staphyphages could be an effective alternative tool to combat bacteria multi-resistance.
基金Supported by the Attestation de Financement de These de Doctorat,Dakar le 28/10/2019.
文摘BACKGROUND In endemic areas,vertical transmission of hepatitis B virus(HBV)remains a major source of the global reservoir of infected people.Eliminating mother-to-child transmission(MTCT)of HBV is at the heart of World Health Organization’s goal of reducing the incidence of HBV in children to less than 0.1%by 2030.Universal screening for hepatitis B during pregnancy and neonatal vaccination are the main preventive measures.AIM To evaluate the efficacy of HBV vaccination combined with one dose of immunoglobulin in children born to hepatitis B surface antigen(HBsAg)-positive mothers in Djibouti city.METHODS We conducted a study in a prospective cohort of HBsAg-positive pregnant women and their infants.The study ran from January 2021 to May 2022,and infants were followed up to 7 mo of age.HBV serological markers and viral load in pregnant women were measured using aVidas microparticle enzyme-linked immunosorbent assay(Biomérieux,Paris,France)and the automated Amplix platform(Biosynex,Strasbourg,France).All infants received hepatitis B immunoglobulin and were vaccinated against HBV at birth.These infants were closely monitored to assess their seroprotective response and for failure of immunoprophylaxis.Simple logistic regression was also used to identify risk factors associated with immunoprophylaxis failure and poor vaccine response.All statistical analyses were performed with version 4.0.1 of the R software.RESULTS Of the 50 pregnant women recruited,the median age was 31 years,ranging from 18 years to 41 years.The MTCT rate in this cohort was 4%(2/50)in HBsAg-positive women and 67%(2/3)in hepatitis B e antigen-positive women with a viral load>200000 IU/mL.Of the 48 infants who did not fail immunoprophylaxis,8(16%)became poor responders(anti-HB<100 mIU/mL)after HBV vaccination and hepatitis B immunoglobulin,while 40(84%)infants achieved a good level of seroprotection(anti-HB>100 mIU/mL).Factors associated with this failure of immunoprophylaxis were maternal HBV DNA levels(>200000 IU/mL)and hepatitis B e antigen-positive status(odds ratio=158,95%confidence interval:5.05-4958,P<0.01).Birth weight<2500 g was associated with a poor immune response to vaccination(odds ratio=34,95%confidence interval:3.01-383.86,P<0.01).CONCLUSION Despite a failure rate of immunoprophylaxis higher than the World Health Organization target,this study showed that the combination of immunoglobulin and HBV vaccine was effective in preventing MTCT of HBV.Therefore,further studies are needed to better understand the challenges associated with immunoprophylaxis failure in infants in Djibouti city.
文摘Introduction: Malaria control needs the development of complementary and/or alternative strategies such as biological controls. Despite, malaria’s current control efforts, the spread and the emergence of insecticide resistance in vectors undermine the fight against vectors. Endonsymbiotic fungi can be a good candidate to include in the existence of Arsenal. However, we know little about endosymbiotic fungi transmission and its impact on malaria transmission. In this paper, the authors aimed to investigate Microsporidia sp MB transgenerational and sexual autodissemination and malaria parasites within Anopheline mosquitoes. Methods: An entomology survey was conducted in Burkina Faso for one year (June 2020 to June 2021) using the Residual Fauna Capture method. Infection rates in collected females, sexual autodissemination of Microsporidia sp MB in both Microsporidia sp MB negative females and Microsporidia sp MB negative males through mating, transgenerational prevalence from parents to offsprings and the correlation between Microsporidia sp MB and Plasmodium falciparum were investigated. Results: Results show Microsporidia sp MB infection in An. gambaie s.l in Burkina Faso. The prevalence was significantly higher (21.78%) in An. coluzzii than An. gambiae s.s (16.89%) (p-value = 0.03). Sexual auto-dissemination of Microsporidia sp MB in Microsporidia sp MB uninfected females was significantly 3-fold lower than those in Microsporidia sp MB uninfected males (9.23% and 33.33%, p-value = 0.03) during mating for An. coluzzii lines. Microsporidia sp MB prevalence was significantly higher through mosquitos’ generations in An. gambaie s.s than An. coluzzii (30.23% vs 26.41%, p-value Microsporidia sp MB and Plasmodium infection rate with 73% of Microsporidia sp MB positive mosquitoes which were negative at Plasmodium infection (p-value Conclusions: Our findings pave the road to developing new malaria control technologies by making Microsporidia sp MB-positive males sexually competitive with wild males to spread the fungus to wild female mosquitoes.
文摘This article presents a three-dimensional analysis of the impact of the angle of incidence of the magnetic field intensity on the electrical performance (series resistance, shunt resistance) of a bifacial polycrystalline silicon solar cell. The cell is illuminated simultaneously from both sides. The continuity equation for the excess minority carriers is solved at the emitter and at the depth of the base respectively. The analytical expressions for photocurrent density, photovoltage, series resistance and shunt resistance were deduced. Using these expressions, the values of the series and shunt resistances were extracted for different values of the angle of incidence of the magnetic field intensity. The study shows that as the angle of incidence increases, the slopes of the minority carrier density for the two modes of operation of the solar cell decrease. This is explained by a drop in the accumulation of carriers in the area close to the junction due to the fact that the Lorentz force is unable to drive the carriers towards the lateral surfaces due to the weak action of the magnetic field, which tends to cancel out as the incidence angle increases, and consequently a drop in the open circuit photovoltage. This, in turn, reduces the Lorentz force. These results predict that the p-n junction of the solar cell will not heat up. The study also showed a decrease in series resistance as the incidence angle of the magnetic field intensity increased from 0 rad to π/2 rad and an increase in shunt resistance as the incidence angle increased. His behaviour of the electrical parameters when the angle of incidence of the field from 0 rad to π/2 rad shows that the decreasing magnetic field vector tends to be collinear with the electron trajectory. This allows them to cross the junction and participate in the external current. The best orientation for the Lorentz force is zero, in which case the carriers can move easily towards the junction.
文摘Activated carbons (ACs) calcined at 400˚C, 500˚C, and 600˚C (AC-400, AC-500, and AC-600) were prepared using palm nut shells from Gabon as raw material and zinc chloride (ZnCl2) as a chemical activating agent. Prepared ACs were characterized by physisorption of nitrogen (N2), determination of diode and methylene blue numbers for studies of porosity and by quantification and determination of surface functional groups and pH at point of zero charge (pHpzc) respectively, for studies of chemical properties of prepared ACs. Then, effects of calcination temperature (Tcal) on porosity and chemical properties of prepared ACs were studied. The results obtained showed that when the calcination temperature increases from 500˚C to 600˚C, the porosity and chemical properties of prepared ACs are modified. Indeed, the methylene blue and iodine numbers determined for activated carbons AC-400 (460 and 7.94 mg·g−1, respectively) and AC-500 (680 and 8.90 mg·g−1, respectively) are higher than those obtained for AC-600 (360 and 5.75 mg·g−1, respectively). Compared to the AC-500 adsorbent, specific surface areas (SBET) and microporous volume losses for AC-600 were estimated to 44.7% and 45.8%, respectively. Moreover, in our experimental conditions, the effect of Tcal on the quantities of acidic and basic functional groups on the surface of the ACs appears negligible. In addition, results of the pHpzc of prepared ACs showed that as Tcal increases, the pH of the adsorbents increases and tends towards neutrality. Indeed, a stronger acidity was determined on AC-400 (pHpzc = 5.60) compared to those on AC-500 and AC-600 (pHpzc = 6.85 and 6.70, respectively). Also according to the results of porosity and chemical characterizations, adsorption being a surface phenomenon, 500˚C appears to be the optimal calcination temperature for the preparation of activated carbons from palm nut shells in our experimental conditions.
文摘Methane generation in landfills and its inadequate management represent the major avoidable source of anthropogenic methane today. This paper models methane production and the potential resources expected (electrical energy production and potential carbon credits from avoided CH4 emissions) from its proper management in a municipal solid waste landfill located in Ouagadougou, Burkina Faso. The modeling was carried out using two first-order decay (FOD) models (LandGEM V3.02 and SWANA) using parameters evaluated on the basis of the characteristics of the waste admitted to the landfill and weather data for the site. At the same time, production data have been collected since 2016 in order to compare them with the model results. The results obtained from these models were compared to experimental one. For the simulation of methane production, the SWANA model showed better consistency with experimental data, with a coefficient of determination (R²) of 0.59 compared with the LandGEM model, which obtained a coefficient of 0.006. Thus, despite the low correlation values linked to the poor consistency of experimental data, the SWANA model models methane production much better than the LandGEM model. Thus, despite the low correlation values linked to the poor consistency of the experimental data, the SWANA model models methane production much better than the LandGEM V3.02 model. It was noted that the poor consistency of the experimental data justifies these low coefficients, and that they can be improved in the future thanks to ongoing in situ measurements. According to the SWANA model prediction, in 27 years of operation a biogas plant with 33% electrical efficiency using biogas from the Polesgo landfill would avoid 1,340 GgCO2e. Also, the evaluation of revenues due to electricity and carbon credit gave a total revenue derived from methane production of US$27.38 million at a cost of US$10.5/tonne CO2e.
文摘Background: Breast cancer is the dominant cancer in women in both developed and developing countries. The objective of this study was to assess the knowledge, attitudes, practices and factors associated with early breast cancer screening among women in the Municipality of Abomey-Calavi in Benin. Methods: This was a cross-sectional, descriptive, analytical study with prospective data collection from October 1 to 8, 2018, involving 1740 women in the Municipality of Abomey-Calavi, aged 18 years or older and selected by WHO four-stage random cluster sampling. Consenting women who were mentally competent, 18 years of age or older at the time of the survey, and residing continuously in the Municipality of Abomey-Calavi for the last six months prior to the survey were included. On the other hand, women who belonged to a breast cancer prevention service, women in whom secondary screening was noted, or non-consenting women were not included. The initial minimum size was estimated by the Schwartz formula with a cluster effect of k = 2. Information was collected by questionnaire survey, entered with Epidata 3.1. Fr and analyzed with R Studio 3.5.1. software. Results: The mean age of the women surveyed was 32.0 ± 11.5 years with a range of 18 and 71 years. Regarding knowledge, the clinical manifestation known by the majority of women was the presence of a nodule (68.50%). In the series, 1308 (75.17%) declared having heard about breast cancer once before, either on the radio, television or from friends and 726 (55.50%) had heard about breast cancer screening. Five hundred and twelve (70.52%) of the 726 who had heard of breast cancer said they knew that breast cancer could be screened earlier. Breast self-examination was the most cited screening method (67.58%). The disease is of natural origin according to 37.84% of them. Regarding attitudes and practices, the prevalence of early breast cancer screening was 12.93%, of which 11.67% declared that they had checked themselves to know whether they were carriers of the disease or not. The main means of the early screening used was breast self-examination (85.78%). Factors associated with early breast cancer screening found in multivariate analysis were age (≤50 years), education level (increasingly higher), marital status (married/coupled), place of residence (downtown), and socioeconomic level (average/high). Conclusion: The frequency of early breast cancer screening among women is still low in the municipality of Abomey-Calavi, although they have a good knowledge of the disease. This raises the need to strengthen awareness of early breast cancer screening.
文摘The study evaluated the growth performance and carcass quality of COBB500 broilers fed two experimental rations incorporating feed and mango fine ED<sub>10</sub> for a batch of 83 birds, ED<sub>20</sub> (batch of 83 birds) in comparison with a commercial control ration CCD (84 birds). For this purpose, 250 day-old chicks of this breed were purchased in Korhogo and transported to Tengréla in Ivory Coast for rearing. The results show that substituting mango provender ans and mango seed flour for maize resulted in rations with costs per kgMS of 215.35FCFA, 2016.93FCFA and 320FCFA for the ED<sub>10</sub>, ED<sub>20</sub> and CCD rations respectively. The production costs per kg of chicken (FCPkgLW) of the CCD ration were significantly higher than those of the ED10 and ED<sub>20</sub> (p 0.05). ADGs were significantly different and decreasing from CCD, ED<sub>20</sub> to ED<sub>10</sub> (p 0.05). Average weights at 42nd day for ED<sub>20</sub> and CCD were homogeneous (p > 0.05) and significantly higher than for ED<sub>10</sub> (p 0.05). By day 49th the average weight of ED<sub>20</sub> had reached and exceeded that of CCD by day 42nd. PSLW, HCW and CCW were significantly different and decreasing from CCW, ED<sub>20</sub> to ED<sub>10</sub> (p 0.05). Average hot (HCY) and cooled (CCY) carcass yields of ED<sub>20</sub> and CCD rations were comparable (p > 0.05) and significantly higher than those of ED<sub>10</sub> ration (p = 0.009) and 0.003). Average drumstick and neck weights were significantly higher and lower for CCD, ED<sub>20</sub> and ED<sub>10</sub> (p 0.05). For all other parts of the cut, the average weights of the CCD ration were significantly higher (p 0.05) than those of the ED<sub>20</sub> and ED<sub>10</sub> rations, which were homogeneous (p 0.05). The incorporation of mango provender and mango seed flour in broiler rations offers the prospect of reduced production costs, less competition between man and animals over cereals, and lean meat production that is more appreciated than that of chickens fed conventional feed. As it stands, the ED<sub>20</sub> ration can be recommended as a growth diet for broilers. It would be necessary to determine the levels of anti-nutritional substances in mango feeds and to assess the in vivo digestibility of mango ingredients and the diets incorporating them.
文摘Civil engineering works require the selection of soil-type materials and the assessment of their geomechanical characteristics. However, the lack of relevant geotechnical mapping to facilitate the prediction of granular material zones for civil engineering works in Benin means that very costly and sometimes inconclusive prospecting has to be undertaken for each project. The aim of this study is to contribute to the availability of geotechnical mapping in Benin. For this purpose, and in order to capitalize on the data, the proposed methodological approach is based on the systematic and controlled recording of data produced by laboratories during geotechnical and geological surveys for road construction projects. To this end, a web platform called ROAD MAT has been designed for data recording. This platform has been tested using data from test results from sixteen boreholes drilled in the Mono department. These results show a predominance of soil class G2 and CBR class P2. The database is steadily expanding, and its use by stakeholders will make it possible to collect and centralize vital data to define benchmarks for greater control of geotechnical risks. This work therefore constitutes a blueprint for the development of geotechnical mapping in Benin.
文摘Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their performance is exploited with lossy compression techniques for images and videos generally using a mixed approach. To achieve our intended objective, which is to study the performance of lossless compression methods, we first carried out a literature review, a summary of which enabled us to select the most relevant, namely the following: arithmetic coding, LZW, Tunstall’s algorithm, RLE, BWT, Huffman coding and Shannon-Fano. Secondly, we designed a purposive text dataset with a repeating pattern in order to test the behavior and effectiveness of the selected compression techniques. Thirdly, we designed the compression algorithms and developed the programs (scripts) in Matlab in order to test their performance. Finally, following the tests conducted on relevant data that we constructed according to a deliberate model, the results show that these methods presented in order of performance are very satisfactory:- LZW- Arithmetic coding- Tunstall algorithm- BWT + RLELikewise, it appears that on the one hand, the performance of certain techniques relative to others is strongly linked to the sequencing and/or recurrence of symbols that make up the message, and on the other hand, to the cumulative time of encoding and decoding.
文摘Candida auris since it discovery in 2009 is becoming a severe threat to human health due to its very quickly spread, its worldwide high resistance to systemic antifungal drugs. In resource-constrained settings where several conditions are met for its emergence and spread, this worrisome fungus could cause large hospital and/or community-based outbreaks. This review aimed to summarize the available data on C. auris in Africa focusing on its epidemiology and antifungal resistance profile. Major databases were searched for articles on the epidemiology and antifungal resistance profile of C. auris in Africa. Out of 2,521 articles identified 22 met the inclusion criteria. In Africa, nearly 89% of African countries have no published data on C. auris. The prevalence of C. auris in Africa was 8.74%. The case fatality rate of C. auris infection in Africa was 39.46%. The main C. auris risk factors reported in Africa were cardiovascular disease, renal failure, diabetes, HIV, recent intake of antimicrobial drugs, ICU admissions, surgery, hemodialysis, parenteral nutrition and indwelling devices. Four phylogenetic clades were reported in Africa, namely clades I, II, III and IV. Candida auris showed a pan-African very high resistance rate to fluconazole, moderate resistance to amphotericin B, and high susceptibility to echinocandins. Finally, C. auris clade-specific mutations were observed within the ERG2, ERG3, ERG9, ERG11, FKS1, TAC1b and MRR1 genes in Africa. This systematic review showed the presence of C. auris in the African continent and a worrying unavailability of data on this resilient fungus in most African countries.
文摘This work investigated the removal, kinetics and thermodynamics of iron(II) ions (Fe(II)) by adsorption in static and dynamic conditions in aqueous media on activated carbons (AC-i30min, AC-i1h, and AC-i24h), prepared from palm nut shells collected in the city of Franceville to Gabon, using potassium hydroxide (KOH) as the activating agent. Results on the elimination of Fe(II) in static and dynamic adsorption on prepared activated carbons (ACs) showed that the AC-i24h adsorbent has the best Fe(II) adsorption capacities at saturation (Qsat). The Qsat obtained on AC-i24h in static and dynamic conditions (17.87 and 10.38 mg/g, respectively) were higher than those of AC-i30min (13.89 and 5.54 mg/g respectively) and AC-i1h (14.92 and 8.64 mg/g respectively). Moreover, the static adsorption was more effective in the removal of Fe(II) ions in aqueous media in our experimental conditions. The percentage removal (%E) of Fe(II) obtained on prepared activated carbons in static conditions was better than those obtained in dynamic conditions, especially on AC-i24h, where the %E was 89.27% in static and 61.56% in dynamic. In kinetics, results showed that the pseudo-second-order kinetic model best described the adsorption mechanisms of Fe(II) on prepared activated carbons in static adsorption, with mainly of chemisorption on the solid surfaces. However, in dynamic conditions, the pseudo-first-order kinetic model was more suitable. In addition to the weak interactions between Fe(II) and the activated carbon surfaces, strong interactions (chemisorption) were also observed. Also, thermodynamic data obtained on AC-i24h in static adsorption indicated that the adsorption of Fe(II) was spontaneous and increased with temperature (ΔG˚ H˚ = 503.54 KJ/mol).
文摘With the aim of enhancing the value of local building materials, the subject of this paper is a thermophysical study of natural Chadian clay from the eastern region of Chad, “Abeche”. Samples were taken from a brickwork in Abeche from a depth of 1 m, then using a clay brick-making press, 4 × 5 × 8 cm3 clay test tubes were made with 2%, 4%, 6% and 8% cow dung, and a 100% clay sample was used as a control. These samples underwent thermophysical characterization using the hot-wire method with a hot-plane option, yielding results that could improve thermophysical performance. The thermal conductivity of the test sample is in the order of 0.715 to 0.420 W/m. K, at 8% for cow dung, so the addition of cow dung as a percentage in the clay matrix enabled us to obtain various satisfactory thermal parameters.
文摘The development of artificial intelligence (AI), particularly deep learning, has made it possible to accelerate and improve the processing of data collected in different fields (commerce, medicine, surveillance or security, agriculture, etc.). Most related works use open source consistent image databases. This is the case for ImageNet reference data such as coco data, IP102, CIFAR-10, STL-10 and many others with variability representatives. The consistency of its images contributes to the spectacular results observed in its fields with deep learning. The application of deep learning which is making its debut in geology does not, to our knowledge, include a database of microscopic images of thin sections of open source rock minerals. In this paper, we evaluate three optimizers under the AlexNet architecture to check whether our acquired mineral images have object features or patterns that are clear and distinct to be extracted by a neural network. These are thin sections of magmatic rocks (biotite and 2-mica granite, granodiorite, simple granite, dolerite, charnokite and gabbros, etc.) which served as support. We use two hyper-parameters: the number of epochs to perform complete rounds on the entire data set and the “learning rate” to indicate how quickly the weights in the network will be modified during optimization. Using Transfer Learning, the three (3) optimizers all based on the gradient descent methods of Stochastic Momentum Gradient Descent (sgdm), Root Mean Square Propagation (RMSprop) algorithm and Adaptive Estimation of moment (Adam) achieved better performance. The recorded results indicate that the Momentum optimizer achieved the best scores respectively of 96.2% with a learning step set to 10−3 for a fixed choice of 350 epochs during this variation and 96, 7% over 300 epochs for the same value of the learning step. This performance is expected to provide excellent insight into image quality for future studies. Then they participate in the development of an intelligent system for the identification and classification of minerals, seven (7) in total (quartz, biotite, amphibole, plagioclase, feldspar, muscovite, pyroxene) and rocks.
文摘Land use dynamics is a prerequisite for identifying natural resource management constraints,the evolution of agrarian practices and population growth.The objective of this research is to improve knowledge of the dynamics of agricultural land use in the dryland(Cinzana)and cotton(Kléla)areas of Mali.The methodology used consisted of planimetric data collection and diachronic analysis using Landsat TM(Thematic Mapper)satellite images from 2000 and OLI(Operational Land Image)from 2020.Degradation and deforestation rates of natural formations were calculated on the one hand,and on the other hand,the speed and intensity of changes were evaluated using the Pontius matrix22 and intensity analysis programs from the transition matrix.The results of the diachronic analysis revealed a clear increase in the area of anthropogenic formations,especially fields and fallow land,at the expense of natural formations.In Cinzana,this was reflected in an overall increase in the area of anthropogenic formations of 45%(i.e.,2.30%per year)and an overall reduction of 45.15%(2.26%per year)in the area of natural units.In Kléla,there was an overall increase of 131%(i.e.,6.54%per year)in the area of fields and fallow land to the detriment of natural formations,which underwent a reduction of 95%(i.e.,4.76%per year)between 2000 and 2020.Definitely,the evolution of landscape units in the research area between 2000 and 2020 points to excessive anthropization of natural formations,which could compromise the sustainability of these formations,with a risk to ecosystem services and agricultural productivity lost.The study recommends the use of agro-ecological practices,and the facilitation of access to agricultural technologies and support services with a view to agricultural intensification.Policy measures to promote an agro-ecological transition should be encouraged.
文摘This study highlighted the physical transformation that agri-food products undergo during their drying. This transformation enormously affects the customer’s choice and the profit margin of the dried product promoter. The example of the experimental study of the potato reveals that the product continually changes its dimensions during its drying. The more the product loses its water, the more the dimensions decrease. The results initially showed that the water parameters such as mass or water content decrease according to the drying principle. The dimensions length L., width l and thickness e. decrease following a linear trend whose mathematical equations which describe them are determined using the office tool, excel. This trend has repercussions on the surface and volume parameters which in turn decreases almost linearly with the product’s water content. Note that the coefficient R2 is not always acceptable, confirming the complex nature of the behavior of organic products.
文摘Invasive candidiasis (IC) is an emerging opportunistic fungal infection associated with high mortality among hospitalized patients. Although the epidemiology of IC is progressively changing worldwide, the trend in Africa still needs to be established. This review aimed to evaluate the epidemiology of IC in Western region of Africa. A comprehensive literature search was performed on major electronic databases to identify relevant articles. DerSimonian and Laird random-effects model was used to pool overall prevalence and estimated incidence data. We identified 1975 articles, among which 23 met our inclusion criteria for the systematic review. Available data showed that only 50% (8/16) of West African countries were reported data on IC and only 25% reported at least one laboratory confirmed IC case. The global prevalence of candidemia and non-candidemic deep-seated candidiasis were 0.35% [95% CI 0.23;0.47] and 0.32% [95% CI 0.00;2.03], respectively. Among clinical IC cases, only 5.21% were reported before 2010, while 50.08% were reported in the past 5 years. The pooled estimated incidence was 5.55/100,000 [95% CI 5.46;5.64] and 1.15/100,000 [95% CI 1.11;1.19, 95% CI]/inhabitants for candidemia, and Candida peritonitis, respectively. The case fatality rate was 57.58%. Low gestational age, exposure to broad-spectrum antibiotics and invasive procedures were associated with a higher risk of IC in newborn patients. Candida albicans (32.98%) was the most common causative species of IC followed by C. tropicalis (11.34%) and C. parapsilosis (6.19%). This study showed the scarcity of IC data in western region of Africa and the existence of undiagnosed IC cases.
基金Supported by CSC(Chinese Scholarship)(Liu Jin Chu[2006]3074)
文摘A platform named EMECS based on embedded Ethernet control system is implemented.A PC running Fedora 6(Linux2.6)works as a central controller.A kit running Linux 2.4 based on Samsung2410A(ARM920t core)works as a remote controller and a DC motor(ESCA P28HSL18-219/204)made by Portescap Company works as a plant.Firstly,system modeling is presented by analyzing the characteristics of Ethernet and the plant,based on a proposed delay measurement method.Secondly,implementation of the system including program and hardware is described in detail.And then the delay is measured and the control results of the system are tested in three cases with different network loads as well.The platform is proved to have flexibility of running different control algorithms and extensibility of adding nodes.Experiment results demonstrate the validity of the system.
文摘In this study, the material is okra, a cucurbitaceous largely consumed in West Africa and South Asia. The influence of the external air parameters on food drying with different size, maturity, shape of the material is considered by convective drying. So, the okra was cut in several parts according to its three characteristic zones, the basis, the middle of the okra and the extremity because the three parts of the vegetable have not the same resistances in transfers by convective drying. The maturity of the okra also has an influence. The okra dries faster in its younger or older age. Okra dries slowly when its maturity is convenient to be consumed. The drying duration of okra with the age of 1, 2, 3, 4 and 5 days is respectively 580, 780, 990, 1200 and 850 min. When we consider the three (matters) constituent of the okra: the skin, the seeds and the central material, the central matter dries faster. The diffusion coefficient was identified in all cases in order to compare the influence of those intrinsic properties of that food.
文摘To the Editor:Accessory gallbladders(AG)are rare and their management are usually challenging.These variations are related with an abnormal division of the bile ducts precursors between the 5th and the 12th week of pregnancy.Harlaftis et al.[1]proposed an anatomical classification of these variations based on the embryologic abnormalities described.In type 1 both gallbladders are connected to the common bile duct at the same location.In type 2 the AG can reach either the common bile duct(ductular type)or an intrahepatic biliary duct(trabecular type).In type 3,three gallbladders are present.
