Background: HIV in pregnant women presented a risk of transmission to newborns. This study was to determine HIV prevalence among pregnant women in the birthing rooms and give antiretrovirals to women infected and thei...Background: HIV in pregnant women presented a risk of transmission to newborns. This study was to determine HIV prevalence among pregnant women in the birthing rooms and give antiretrovirals to women infected and their newborns. Methods: A preliminary study was conducted from 2013 to 2015 at the Mother and Child Hospital. Pregnant women were counseled and tested for HIV-antibody according to the national algorithm using Determine HIV 1 & 2 and Immunocomb II Bispot HIV1 & 2. The women screened HIV-negative during the prenatal consultation and who accepted a second test were screened in the birth room. The data collected were processed using the Access Microsoft office 16 and SPSS software version 18. Results: A total of 6080 pregnant women were tested before and in the birth room. Of these, 5943 (97.4%) were detected as HIV-negative and 159 (2.6%) were HIV-positive. Of the 5943 with HIV-negative status, 1333 accepted the second test in the birth room, 10 of which have become HIV-positive. The rate of seroconversions was 0.75%. Conclusion: This study determined the prevalence of HIV in pregnant women. The result reveals the importance and necessity of repeating the screening test in the birth room because of the possibility of seroconversion or new infection during pregnancy.展开更多
Objective: Class B carbapenemases are bacterial enzymes that catalyze the hydrolysis of β-lactam core antibiotics, except for monobactams. The objective of this study was to identify the carbapenemase gene bla<sub...Objective: Class B carbapenemases are bacterial enzymes that catalyze the hydrolysis of β-lactam core antibiotics, except for monobactams. The objective of this study was to identify the carbapenemase gene bla<sub>IMP</sub> in the genus Klebsiella at the Charles De Gaulle Pediatric University Hospital (CHUP-CDG) of Ouagadougou, Burkina Faso. Methods: The study involved 17 bacterial strains responsible for human infection and isolated from various biological samples during the period from 2009 to 2013. The strains were tested for antimicrobial susceptibility to cefotaxime, ceftazidime and imipenem using the Mueller-Hinton agar diffusion method. The carbapenemases resistance genes were detected by conventional PCR using specific primers at the molecular biology laboratory of CERBA/LABIOGENE, Ouagadougou, Burkina Faso. Results: The antibiotic susceptibility test showed high resistance of the 17 Klebsiella isolates tested to cephalosporins. A high cefotaxime-resistance rate (82.35%) and ceftazidime-resistance rate (88.23%) was found among the strains tested against 11.76% resistance rate for imipenem. Analysis of PCR products by gel electrophoresis revealed 4 strains (23.53%) with bla<sub>IMP</sub>-type gene. Conclusion: Klebsiella is a well-known bacterium in clinical practice. The present study demonstrated the bla<sub>IMP</sub>-type gene in cephalosporin-resistant strains of Klebsiella at CHUP-CDG. More effective monitoring and treatment solutions are needed to prevent the spread of these resistant strains.展开更多
The highly active antiretroviral treatment (HAART) has allowed people living with HIV to live longer with a better quality of life. However, toxicity and the emergence of drug resistance arise from HAART use. Therefor...The highly active antiretroviral treatment (HAART) has allowed people living with HIV to live longer with a better quality of life. However, toxicity and the emergence of drug resistance arise from HAART use. Therefore, new antiretroviral therapy is needed since no cure or vaccine is available against HIV. Virus-host interaction has been proven to be important in the last decade. Host factors such as the C-C chemokine receptor type 5 (CCR5), a receptor used by HIV to penetrate host cells, have led to the discovery of the Maraviroc, which is an antiretroviral medication used in the United States. In contrast, other factors like C-X-C Motif Chemokine Receptor 4 (CXCR4) and the Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G (APOBEC3G), a potent host defense factor against HIV, is under investigation. APOBEC3G antiviral activity remains a possible therapeutic target against HIV. This systematic review aimed to synthesize the available evidence on the role of APOBEC3G polymorphisms and their expression on HIV infection disease progression in Africa. We used Web of Science, PubMed, Embase, and Google Scholar and searched for relevant publications in French or English reporting on APOBEC3G polymorphisms association with HIV infection in African populations from January 2009 to May 2023. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyzes) was used to process for reporting systematic review. Fifteen studies were included, of which seven were on APOBEC3G polymorphisms and eight were on APOBEC3G expression. Among the APOBEC3G polymorphisms, the most studied was H186R or rs8177832. The average of the minor allele frequency of H186R of APOBEC3G available for the studies included in this study was 0.29 with a 95% CI (0.172;0.401) and varied from 0.108 reported in Uganda to 0.47 recorded from Burkina Faso. The polymorphism H186R was not associated with HIV status in Southern Africa. However, the referent allele of H186R was protective against HIV infection in Western Central Africa, while in West Africa, it was the minor allele (G) of H186R which was protective against HIV. This review warrants a need to increase research on APOBEC3G, from its variants to its hypermutations on the continent with an essential variety of HIV-1 subtypes, to impact the research on A3G-based anti-HIV strategies.展开更多
The Pouni area is made up of basalts belonging to the Boromo belt, lamprophyres and granitoids. These geological formations are similar to geological formations of the same type in other regions of the Palaeoproterozo...The Pouni area is made up of basalts belonging to the Boromo belt, lamprophyres and granitoids. These geological formations are similar to geological formations of the same type in other regions of the Palaeoproterozoic domain of the Man/Leo shield. This study, which focused on the petrographic and geochemical characteristics of these geological formations, led to the following main conclusions: The lamprophyres are basic plutonic rocks that cut through other geological formations. The basalt belongs to the northern part of the Borormo belt and is thought to be a relic of overthickened oceanic plateaus. There are two groups of granitoid rocks. The granodiorite has a geochemical signature close to that of Archean TTGs and is metaluminous in character. It has a low potassium content. The minor element and rare earth element spectra indicate that it could be derived from partial melting of basic magmatic rocks. Biotite granites are peraluminous and highly potassic. Minor element contents and rare earth spectra indicate that they could be derived from partial melting of felsic materials. Geotectonic diagrams show that the granitoids identified in the Pouni zone were emplaced in an active tectonic context, similar to that of present-day subduction zones.展开更多
This study, carried out in the Léo square degree (west-central Burkina Faso) in the Palaeoproterozoic domain of the Man/Léo ridge, aims to define the shapes and positions of granitic plutons and the organisa...This study, carried out in the Léo square degree (west-central Burkina Faso) in the Palaeoproterozoic domain of the Man/Léo ridge, aims to define the shapes and positions of granitic plutons and the organisation of deformation structures using aeromagnetic data. These data have shown that there are small sub-circular granitic bodies to the north of the granitic masses in this region, and a large sub-circular granitic body to the south, around which are other smaller granitic bodies. The lineament map shows that the deformation structures are organised along three main directions and largely form these sub-circular plutonic bodies. We suggest that the granitic plutons are coalescent, pending identification of the internal structures of these granites to further refine the geodynamic model.展开更多
South of Godé, in the central-western region of Burkina Faso, granitoids of Paleoproterozoic age are similar to those of the Man/Leo shield. This study focused on the petrographic and geochemical characteristics ...South of Godé, in the central-western region of Burkina Faso, granitoids of Paleoproterozoic age are similar to those of the Man/Leo shield. This study focused on the petrographic and geochemical characteristics of these granitoids, with the following results: 1) The tonalite that outcrops in the south-west of the study area belongs to the TTG group or first generation granitoids. They are most often ribboned at outcrop and have a geochemical signature close to that of Archean TTGs. Tonalite has a metaluminous character and the REE spectrum indicates that it may be derived from partial melting of basic magmatic rocks. 2) Biotite granites have no outcrop structure. They are weakly metaluminous to peraluminous and potassic to highly potassic. Their rare earth spectra indicate that they may be derived from the partial melting of TTG granitoids. 3) Geotectonic diagrams show that the granitoids studied to the south of Godé were emplaced in an active tectonic context similar to that of present-day subduction zones.展开更多
The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compoun...The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compound as an insulating eco-material in building in a tropical climate. The composites samples were developed by mixing plaster with raffia vinifera particles (RVP) using three different sizes (1.6 mm, 2.5 mm and 4 mm). The effects of four different RVP incorporations rates (i.e., 0wt%, 5wt%;10wt%;15wt%) on physical, thermal, mechanicals properties of the composites were investigated. In addition, the use of the raffia vinifera particles and plaster based composite material as building envelopes thermal insulation material is studied by the habitable cell thermal behavior instrumentation. The results indicate that the incorporation of raffia vinifera particle leads to improve the new composite physical, mechanical and thermal properties. And the parametric analysis reveals that the sampling rate and the size of raffia vinifera particles are the most decisive factor to impact these properties, and to decreases in the thermal conductivity which leads to an improvement to the thermal resistance and energy savings. The best improvement of plaster composite was obtained at the raffia vinifera particles size between 2.5 and 4.0 mm loading of 5wt% (C95P5R) with a good ratio of thermo-physical-mechanical properties. Additionally, the habitable cell experimental thermal behavior, with the new raffia vinifera particles and plaster-based composite as thermal insulating material for building walls, gives an average damping of 4°C and 5.8°C in the insulated house interior environment respectively for cold and hot cases compared to the outside environment and the uninsulated house interior environment. The current study highlights that this mixture gives the new composite thermal insulation properties applicable in the eco-construction of habitats in tropical environments.展开更多
Burkina Faso is a malaria-endemic country, with a high incidence of G6PD deficiency (G6PDd), which recorded its first case of COVID-19 in March 2020. G6PDd leads to a decrease in the efficiency of erythrocytes to comb...Burkina Faso is a malaria-endemic country, with a high incidence of G6PD deficiency (G6PDd), which recorded its first case of COVID-19 in March 2020. G6PDd leads to a decrease in the efficiency of erythrocytes to combat oxidative stress, while SARS-CoV-2 infection induces massive production of Reactive Oxygen Species (ROS) in patients. In the present review, we discuss a possible link between G6PDd and SARS-CoV-2 infection. The mean prevalence of G6PDd in Burkina Faso is estimated at 16.6% among males and 6.5% among females. A total of 21,128 cases of COVID-19 have been recorded in Burkina Faso with 387 deaths reported (with a mortality rate of 1.15% among diagnosed cases) as of August 30, 2022. To our knowledge, no association study between G6PDd and SARS-CoV-2 infection has been conducted to date in Burkina Faso. However, several case reports around the world have described elevated risks of hemolysis and thrombosis, and other complications among G6PD-deficient patients infected with SARS-CoV-2. The use of Hydroxychloroquine (HCQ) has also been deemed unsafe by some authors for the treatment of COVID-19 among patients with G6PDd. Although HCQ has been shown to be well tolerated in COVID-19 patients in Burkina Faso, the drug could induce hemolytic crises in people with G6PD deficiency. G6PD is important in regulating ROS and maintaining erythrocyte homeostasis. In view of its high prevalence in Burkina Faso, determination of the G6PD status is required in COVID-19 patients for adequate management such as identifying a subset of COVID-19 patients for whom close monitoring and supportive care may be essential and to restrict treatment with HCQ.展开更多
Several fungal species are responsible for diseases that damage sesame crop and cause production losses. These seed-borne fungi cause serious damage by reducing seed germination. To identify the fungi associated with ...Several fungal species are responsible for diseases that damage sesame crop and cause production losses. These seed-borne fungi cause serious damage by reducing seed germination. To identify the fungi associated with sesame seeds in Burkina Faso, 72 sesame seed samples were collected from 24 localities in the main production areas (Sudanian zone, Sudano-Sahelian zone, Sahelian zone). These samples were submitted for seed health analysis using the blotting paper incubation method. The results obtained revealed that the seed samples were contaminated by various fungi, the main ones being: Fusarium spp. Link: Fr. infecting 97.22% of the samples, Macrophomina phaseolina (Tassi) Goid. (90.28%), Alternaria sesamicola E. Kawamura (83.33%), Curvularia lunata (Wakker) Boedijn (76.39%), Cercospora sesami A. Zimmerm. (73.61%), Phoma sorghina Boerema, Dorenbosch, & Van Kesteren (73.61%), Aspergillus flavus Link: Fr. (69.44%), Cladosporium sphaerospermum Penz. (56.94%), Rhizopus sp. Ehrenb. (40.28%) and A. niger Tiegh. (36.11%). In each seed sample, 0.25% to 94% of the seeds host one or more fungal species. Regarding the climatic zones, the results revealed that A. sesamicola and A. flavus were more represented in the Sudanian zone than in the Sudano-Sahelian and Sahelian zones;while P. sorghina, and C. sphaerospermum were more encountered in the Sahelian zone than in the other two zones. This study showed that the majority of sesame seeds produced and used by farmers in Burkina Faso host one or more species of fungi at high levels.展开更多
Over the past three decades, genomic and epigenetic sciences have identified more than 70 genes involved in the molecular pathophysiology of Alzheimer’s disease (AD). DNA methylation, abnormal histone and chromatin r...Over the past three decades, genomic and epigenetic sciences have identified more than 70 genes involved in the molecular pathophysiology of Alzheimer’s disease (AD). DNA methylation, abnormal histone and chromatin regulation and the action of various miRNAs induce AD. The identification of mutated genes has paved the way for the development of diagnostic kits and the initiation of gene therapy trials. However, despite major advances in neuroscience research, there is yet no suitable treatment for AD. Therefore, the early diagnosis of this neurodegenerative disease raises several ethical questions, including the balance between the principle of non-maleficence and the principle of beneficence. The aims of this research were to present the genomic and ethical aspects of AD, and to highlight the ethical principles involved in its presymptomatic diagnosis and therapy. A systematic review of the literature in PubMed, Google Scholar and Science Direct was carried out to outline the genomic aspects and ethical principles relating not only to the presymptomatic diagnosis of AD, but also to its gene therapy. A total of 16 publications were selected. AD is a multifactorial disease that can be genetically classified into Sporadic Alzheimer’s Disease and Familial Alzheimer’s Disease based on family history. Gene therapy targeting specific disease-causing genes is a promising therapeutic strategy. Advancements in artificial intelligence applications may enable the prediction of AD onset several years in advance. While early diagnosis of AD may empower patients with full decision competence for early decision-making, it also carries implications for the patient’s family members, who are at risk of developing the disease, potentially becoming a source of confusion or anxiety. AD has a significant impact on the life of individuals at risk and their families. Given the absence of disease modifying therapy, genetic screening and early diagnosis for this condition raise ethical issues that must be carefully considered in the context of fundamental bioethical principles, including autonomy, beneficence, non-maleficence, and justice.展开更多
Background and Aim: Sarcocephalus latifolius is a medicinal plant commonly used in traditional medicine to treat various diseases. The aim of the present study is to evaluate the hepatoprotective activity of Sarcoceph...Background and Aim: Sarcocephalus latifolius is a medicinal plant commonly used in traditional medicine to treat various diseases. The aim of the present study is to evaluate the hepatoprotective activity of Sarcocephalus latifolius fruits aqueous extract against paracetamol-induced liver damage in rats. Material and Methods: Aqueous extract of Sarcocephalus latifolius fruits at doses of 100, 250 and 500 mg/kg were administered orally to rats with paracetamol-induced hepatotoxicity (1 g/kg). The treatment with the extract and paracetamol lasted 7 days. Silymarin (50 mg/kg) was given as reference control. All tested drugs were administered orally. Results: Our results show that the Sarcocephalus latifolius fruits extract induced a significant reduction (p < 0.05) of serum enzymes alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), alkaline phosphatase (PAL) and total bilirubin (TB). Then, the extract at the dose of 500 mg/kg showed a better protection (p < 0.001) of hepatocytes with a percentage of protection of 43.59% ± 2.03%;59.43% ± 4.12%;73.29% ± 5.72% and 62.55% ± 7.48% for ALAT, ASAT, PAL and TB, respectively. The histology of livers exposed to paracetamol shows an inflammation of the hepatocytes. In addition, there was a significant alteration of the liver parenchyma. The 500 mg/kg extract showed a resorption of the inflammation. Histopathological examination showed that the extract regenerated paracetamol-induced liver damage. Conclusion: Aqueous extract of Sarcocephalus latifolius fruits has hepatoprotective activity against paracetamol-induced hepatotoxicity in rats. But it would be important to evaluate the activity of aqueous extract of Sarcocephalus latifolius fruits on oxidative stress parameters in vivo in rats. .展开更多
From November 2020 to August 2022, the diet of 12 fish species from the Samandeni reservoir was examined in order to describe the diet and the trophic level of each of them. The analysis of this vital function allows ...From November 2020 to August 2022, the diet of 12 fish species from the Samandeni reservoir was examined in order to describe the diet and the trophic level of each of them. The analysis of this vital function allows a better knowledge of the concerned ecosystem and gives opportunity for its better management. The fish were sampled with gill nets and cast net. A total of 213 stomach contents of individuals belonging to 12 species grouped in 7 families and 10 genera were analysed. Results showed low to medium vacuity coefficients. The preys were mainly composed of fish, insects, detritus, zooplankton and phytoplankton. Variability in the use of resources by individuals was evident. Thus, the 12 species were classified as fish-eating predators, granivorous, zooplanktivorous, insectivorous and filter-feeding microphages. Then, the fish trophic structure of the Samandeni reservoir was elaborated.展开更多
Introduction: Hepatic diseases comprise inflammations of the liver, which can originate from drug-induced, toxic, autoimmune sources and particularly hepatitis B and C virus infection. The outcome of the disease is li...Introduction: Hepatic diseases comprise inflammations of the liver, which can originate from drug-induced, toxic, autoimmune sources and particularly hepatitis B and C virus infection. The outcome of the disease is linked to interactions between the immune system and the virus, and also depends on the age and immune status of the patient. The aim of this study was to evaluate the association of a MAP3K14 (rs2074292), CD40 (rs1883832) polymorphism and chronic hepatitis B virus carriage in a population from Burkina Faso. Methods: In this case-control analysis, 223 and 173 samples, consisting of 90 and 53 controls and 133 and 120 cases, were examined for MAP3K14 and CD40 respectively. The cases included patients with Chronic Hepatitis B (CHB), cirrhosis or hepatocellular carcinoma (HCC). Genomic DNA extraction was executed using INVITROGEN and FAVORGEN kits. Genotyping of MAP3K14 (rs2074292) and CD40 (rs1883832) gene polymorphisms was accomplished via real-time PCR on the QuantStudioTM 5 Real-Time instrument, followed by allelic discrimination using TaqMan Genotyper Software. Data was interpreted using SPSS version 20 and Epi info version 7.5.2.0. Odds ratios (OR), confidence intervals (CI), and p-values were derived for risk and significance evaluation. Results: This study showed that the heterozygous CT genotype and the mutated T allele of the CD40 (rs1883832) gene are involved in the progression of chronic hepatitis to cirrhosis and hepatocellular carcinoma in HBV-infected patients. However, no association was found between polymorphisms in the MAP3K14 gene (rs2074292) and the progression of HBV infection. By combining the two polymorphisms, we observed either high risk or protection, depending on the genotypes of the MAP3K14 and CD40 genes simultaneously carried by the patient. Conclusion: Polymorphisms of the MAP3K14 and CD40 genes are associated with the evolution of HBV infection.展开更多
The multiplication of heavy vehicle axles and road overloads are phenomena that are becoming increasingly important on the road network of the WAEMU community. These phenomena, although framed by standards, have an im...The multiplication of heavy vehicle axles and road overloads are phenomena that are becoming increasingly important on the road network of the WAEMU community. These phenomena, although framed by standards, have an impact on the durability of pavements. In this manuscript it is a question of evaluating the life of the road under the effect of traffic of these multi-axle vehicles and the different tolerances of overloads observed on the road network. To achieve this, a modeling of a bituminous pavement was made with the software ALIZE Lcpc Version 231 based on the principle of the French method of sizing. An inventory of multi-axle heavy goods vehicles was also made on a road with a weighing station. This traffic counting made it possible to classify heavy goods vehicles into three categories, namely: 1) trucks, 2) dual-wheeled semi-trailers and 3) single-wheeled semi-trailers. The results obtained show that in terms of aggressiveness, single-wheeled semi-trailers are the most aggressive, followed by heavy goods vehicles in the category of trucks with more than five axles and semi-trailers with dual wheels with more than seven axles. The durability of the road depends on the aggressiveness of heavy goods vehicles, it was found that the tolerance threshold for overloads of 15% of the total permissible rolling weight (TARW) or the total permissible laden weight (TALW) currently granted in the Community area needs to be reviewed. For durable road surfaces, this tolerance may only be allowed for heavy goods vehicles of type P11, P12 and P13. The 5% tolerance can be applied to all vehicles except heavy goods vehicles with single wheels.展开更多
The paper designed a non-contact system in order to perform the application (on a runway) of the Global Reporting Format (GRF) developed by International Civil Aviation Organization (ICAO). The system involves devices...The paper designed a non-contact system in order to perform the application (on a runway) of the Global Reporting Format (GRF) developed by International Civil Aviation Organization (ICAO). The system involves devices that film the surface (a runway in our case) from the air and displays the contaminant (water) body and measures the depth of the water automatically during the inspection. While measuring, data are sent to a computer used as a receiver. The developed devices are automatic devices implemented specially to use during rainy weather or even for some other cases. The aerial system uses a raspberry pi 4 model B, a camera, a laser sensor, an ultrasonic module, a Virtual Network Computing (VNC) and python codes developed by the authors. Results obtained show that using these devices to retrieve the Runway Condition Report (RCR) is very fast and human presence on the runway is not needed. The results obtained using these devices show that the method used herein is a proper solution to the GRF issues in the rainy areas, where the contaminant body detection and the accurate depth measurement were not well estimated because of the lack of a suitable method.展开更多
Highly turbulent environment, the solar wind is a stream of very energetic particles mainly made of protons and electrons. During its trip in the interplanetary space, this solar flow becomes more accelerated during t...Highly turbulent environment, the solar wind is a stream of very energetic particles mainly made of protons and electrons. During its trip in the interplanetary space, this solar flow becomes more accelerated during the outer minima (descending phases) of the solar cycles and can therefore influence all of humanity and its technology. These disturbances lead to socio-economic consequences requiring a precise knowledge of the climate variability. Using a statistical approach, we evaluate the response of the Earth’s magnetosphere to the High-Speed Solar Winds (HSSW) forcing during the peaks of the last five outer minima. To do so, 1UA data of solar wind and magnetic field parameters were extracted from OMNI browser. Analysis of the energetic solar plasma particles shows that strong geomagnetic field variations can occur even in the absence of large solar disturbances. While the normalized reconnection rate was estimated to be ~21% of the total variance of the magnetospheric variables, the upstream of the magnetic cavity was perturbed 80% of the time with large energies recorded. As a result, Earth’s magnetosphere becomes denser (i.e., more drag), which is a problem for spacecraft. Thus, the coupled solar wind-magnetosphere system follows scale-invariant dynamics and is in a state far from equilibrium. Our analysis provides insight into the main cause of geomagnetic storms with more than 97% of HSSW imposed in the range 300 - 850 km/s. These high-speeds lead to auroras that can disrupt electrical and communication systems.展开更多
In this paper we report on the foF2 variabilities for two equatorial regions (Ouagadougou: Lat. 12.4°N;Long. 358.5°E, Dip. 1.43°S;and Manila: Lat. 14°36'15.12''N;Long. 120°58'5...In this paper we report on the foF2 variabilities for two equatorial regions (Ouagadougou: Lat. 12.4°N;Long. 358.5°E, Dip. 1.43°S;and Manila: Lat. 14°36'15.12''N;Long. 120°58'55.92''E;Dip. 0.6°S) during solar cycles 20 and 21 minima and maxima phases. Many previous works have argued on the diurnal and seasonal variation of foF2 for different solar events conditions for latitudinal position. But there are few investigations for Africa equatorial region longitudinal variation. The present paper’s goal is to outline possible similarity in foF2 behavior between variations for better understanding of physical process lead to some observed phenomenon in Asia-Africa equatorial sector. The F-layer critical frequency (foF2) data observed from the two equatorial ionosonde stations have been used for the present comparative study. The results show significant similarity between the critical frequency (foF2) seasonal variations over the time intervals 1976-1996. During day-time measured data from Manila station are higher than those from Ouagadougou station. That may lie in that Manila is closer to equatorial ionization crest region. During solar minimum phase, the longitudinal variation of foF2 shows two crossing points (11:00 UT and 22:00 UT) between the foF2 profiles form the two stations for all seasons regardless of the solar cycle. However during intense solar activity condition, the number of crossing-point between measured data from Manila and Ouagadougou stations varies by seasons and solar cycle. This phenomenon may be due to the compilations of severe activities (storms, coronal mass ejection, heliosheet fluctuations) during the solar maximum phases.展开更多
This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried o...This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried out from the two nearest days (previous and following of quietest day). The study uses International Reference Ionosphere (IRI) for ionosphere modeling. The located station is Ouagadougou, in West Africa. Solar minimum of phase 22 is considered in this study. Using three core principles of ionosphere modeling under IRI running conditions, the study enables to carry out Peak of electron density in F2-layer values during the quietest days of the characteristic months for the four different seasons. These parameters are compared to those of the previous and the following of the quietest days (the day before and following each quietest selected day) at the same hour. The knowledge of NmF2 values at the quietest days and at the two nearest days enables to calculate the relative error that can be made on this parameter. This calculation highlights insignificant relative errors. This means that NmF2 values at the two nearest days of each quietest day on solar minimum can be used for simulating the quietest days’ behavior. NmF2 values obtained by running IRI model have good correlation with those carried out by Thermosphere-Ionosphere-Electrodynamics-General Circulation Model (TIEGCM).展开更多
In this study, the authors investigated the performance of different buffer layers through the electrical parameters such as J<sub>sc</sub>, V<sub>oc</sub>, QE and η of the quaternary system C...In this study, the authors investigated the performance of different buffer layers through the electrical parameters such as J<sub>sc</sub>, V<sub>oc</sub>, QE and η of the quaternary system Cu(In,Ga)Se<sub>2</sub> solar cells. The performance of Cu(In,Ga)Se<sub>2</sub>solar cells has been modeled and numerically simulated by using the SCAPS- 1D device simulation tool. The cells with a ZnSe, Zn(O,S) and (Zn,Mg)O buffer layers were compared with the reference CdS buffer layer. The investigation of ZnSe, Zn(O, S) and (Zn,Mg)O-based cells to substitute the traditional CdS in the future shows that the ZnSe-buffer layer is a potential material to replace CdS, which revealed the best efficiency of 20.76%, the other electrical parameters are: J<sub>SC</sub> = 34.6 mA/cm<sup>2</sup>, V<sub>OC</sub> = 0.76 V and FF = 79.6%. The losses as a function of the temperature are estimated at 0.1%/K, among all kinds of buffer layers studied. We have also shown that the use of a high band-gap buffer layer is necessary to obtain a better short-circuit current density J<sub>SC</sub>. From our results, we note that the chalcogenide solar cells with Zn-based alternative buffer layer have almost the same stability thatthe traditional CdS buffer layer solar cells have.展开更多
Ionosphere parameters determination is used to characterize its composition in particles. These results have been compared to data curried from Ouagadougou station. The present study deals with Total Electron Contents...Ionosphere parameters determination is used to characterize its composition in particles. These results have been compared to data curried from Ouagadougou station. The present study deals with Total Electron Contents (TEC) results determined by Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) version 1.94 and International Reference Ionosphere (IRI) version 2012 during solar cycle 22. The minimum and maximum phases of solar cycle 22 are considered in this study for TEC determination. The station is located at Ouagadougou, in western Africa, characterized by its latitude (12.4°N) and longitude (358.5°E). The present study completes the two previous articles on hmF2 and foF2 parameters determination on the same station by comparison between TEC results carried out from TIEGCM and IRI models. So that, quiet time condition is determined by Aa (≤20 nT) for the five quietest days in each characteristic month of seasons. Rz values characterize minimum and maximum solar cycle phases.展开更多
文摘Background: HIV in pregnant women presented a risk of transmission to newborns. This study was to determine HIV prevalence among pregnant women in the birthing rooms and give antiretrovirals to women infected and their newborns. Methods: A preliminary study was conducted from 2013 to 2015 at the Mother and Child Hospital. Pregnant women were counseled and tested for HIV-antibody according to the national algorithm using Determine HIV 1 & 2 and Immunocomb II Bispot HIV1 & 2. The women screened HIV-negative during the prenatal consultation and who accepted a second test were screened in the birth room. The data collected were processed using the Access Microsoft office 16 and SPSS software version 18. Results: A total of 6080 pregnant women were tested before and in the birth room. Of these, 5943 (97.4%) were detected as HIV-negative and 159 (2.6%) were HIV-positive. Of the 5943 with HIV-negative status, 1333 accepted the second test in the birth room, 10 of which have become HIV-positive. The rate of seroconversions was 0.75%. Conclusion: This study determined the prevalence of HIV in pregnant women. The result reveals the importance and necessity of repeating the screening test in the birth room because of the possibility of seroconversion or new infection during pregnancy.
文摘Objective: Class B carbapenemases are bacterial enzymes that catalyze the hydrolysis of β-lactam core antibiotics, except for monobactams. The objective of this study was to identify the carbapenemase gene bla<sub>IMP</sub> in the genus Klebsiella at the Charles De Gaulle Pediatric University Hospital (CHUP-CDG) of Ouagadougou, Burkina Faso. Methods: The study involved 17 bacterial strains responsible for human infection and isolated from various biological samples during the period from 2009 to 2013. The strains were tested for antimicrobial susceptibility to cefotaxime, ceftazidime and imipenem using the Mueller-Hinton agar diffusion method. The carbapenemases resistance genes were detected by conventional PCR using specific primers at the molecular biology laboratory of CERBA/LABIOGENE, Ouagadougou, Burkina Faso. Results: The antibiotic susceptibility test showed high resistance of the 17 Klebsiella isolates tested to cephalosporins. A high cefotaxime-resistance rate (82.35%) and ceftazidime-resistance rate (88.23%) was found among the strains tested against 11.76% resistance rate for imipenem. Analysis of PCR products by gel electrophoresis revealed 4 strains (23.53%) with bla<sub>IMP</sub>-type gene. Conclusion: Klebsiella is a well-known bacterium in clinical practice. The present study demonstrated the bla<sub>IMP</sub>-type gene in cephalosporin-resistant strains of Klebsiella at CHUP-CDG. More effective monitoring and treatment solutions are needed to prevent the spread of these resistant strains.
文摘The highly active antiretroviral treatment (HAART) has allowed people living with HIV to live longer with a better quality of life. However, toxicity and the emergence of drug resistance arise from HAART use. Therefore, new antiretroviral therapy is needed since no cure or vaccine is available against HIV. Virus-host interaction has been proven to be important in the last decade. Host factors such as the C-C chemokine receptor type 5 (CCR5), a receptor used by HIV to penetrate host cells, have led to the discovery of the Maraviroc, which is an antiretroviral medication used in the United States. In contrast, other factors like C-X-C Motif Chemokine Receptor 4 (CXCR4) and the Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G (APOBEC3G), a potent host defense factor against HIV, is under investigation. APOBEC3G antiviral activity remains a possible therapeutic target against HIV. This systematic review aimed to synthesize the available evidence on the role of APOBEC3G polymorphisms and their expression on HIV infection disease progression in Africa. We used Web of Science, PubMed, Embase, and Google Scholar and searched for relevant publications in French or English reporting on APOBEC3G polymorphisms association with HIV infection in African populations from January 2009 to May 2023. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyzes) was used to process for reporting systematic review. Fifteen studies were included, of which seven were on APOBEC3G polymorphisms and eight were on APOBEC3G expression. Among the APOBEC3G polymorphisms, the most studied was H186R or rs8177832. The average of the minor allele frequency of H186R of APOBEC3G available for the studies included in this study was 0.29 with a 95% CI (0.172;0.401) and varied from 0.108 reported in Uganda to 0.47 recorded from Burkina Faso. The polymorphism H186R was not associated with HIV status in Southern Africa. However, the referent allele of H186R was protective against HIV infection in Western Central Africa, while in West Africa, it was the minor allele (G) of H186R which was protective against HIV. This review warrants a need to increase research on APOBEC3G, from its variants to its hypermutations on the continent with an essential variety of HIV-1 subtypes, to impact the research on A3G-based anti-HIV strategies.
文摘The Pouni area is made up of basalts belonging to the Boromo belt, lamprophyres and granitoids. These geological formations are similar to geological formations of the same type in other regions of the Palaeoproterozoic domain of the Man/Leo shield. This study, which focused on the petrographic and geochemical characteristics of these geological formations, led to the following main conclusions: The lamprophyres are basic plutonic rocks that cut through other geological formations. The basalt belongs to the northern part of the Borormo belt and is thought to be a relic of overthickened oceanic plateaus. There are two groups of granitoid rocks. The granodiorite has a geochemical signature close to that of Archean TTGs and is metaluminous in character. It has a low potassium content. The minor element and rare earth element spectra indicate that it could be derived from partial melting of basic magmatic rocks. Biotite granites are peraluminous and highly potassic. Minor element contents and rare earth spectra indicate that they could be derived from partial melting of felsic materials. Geotectonic diagrams show that the granitoids identified in the Pouni zone were emplaced in an active tectonic context, similar to that of present-day subduction zones.
文摘This study, carried out in the Léo square degree (west-central Burkina Faso) in the Palaeoproterozoic domain of the Man/Léo ridge, aims to define the shapes and positions of granitic plutons and the organisation of deformation structures using aeromagnetic data. These data have shown that there are small sub-circular granitic bodies to the north of the granitic masses in this region, and a large sub-circular granitic body to the south, around which are other smaller granitic bodies. The lineament map shows that the deformation structures are organised along three main directions and largely form these sub-circular plutonic bodies. We suggest that the granitic plutons are coalescent, pending identification of the internal structures of these granites to further refine the geodynamic model.
文摘South of Godé, in the central-western region of Burkina Faso, granitoids of Paleoproterozoic age are similar to those of the Man/Leo shield. This study focused on the petrographic and geochemical characteristics of these granitoids, with the following results: 1) The tonalite that outcrops in the south-west of the study area belongs to the TTG group or first generation granitoids. They are most often ribboned at outcrop and have a geochemical signature close to that of Archean TTGs. Tonalite has a metaluminous character and the REE spectrum indicates that it may be derived from partial melting of basic magmatic rocks. 2) Biotite granites have no outcrop structure. They are weakly metaluminous to peraluminous and potassic to highly potassic. Their rare earth spectra indicate that they may be derived from the partial melting of TTG granitoids. 3) Geotectonic diagrams show that the granitoids studied to the south of Godé were emplaced in an active tectonic context similar to that of present-day subduction zones.
文摘The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compound as an insulating eco-material in building in a tropical climate. The composites samples were developed by mixing plaster with raffia vinifera particles (RVP) using three different sizes (1.6 mm, 2.5 mm and 4 mm). The effects of four different RVP incorporations rates (i.e., 0wt%, 5wt%;10wt%;15wt%) on physical, thermal, mechanicals properties of the composites were investigated. In addition, the use of the raffia vinifera particles and plaster based composite material as building envelopes thermal insulation material is studied by the habitable cell thermal behavior instrumentation. The results indicate that the incorporation of raffia vinifera particle leads to improve the new composite physical, mechanical and thermal properties. And the parametric analysis reveals that the sampling rate and the size of raffia vinifera particles are the most decisive factor to impact these properties, and to decreases in the thermal conductivity which leads to an improvement to the thermal resistance and energy savings. The best improvement of plaster composite was obtained at the raffia vinifera particles size between 2.5 and 4.0 mm loading of 5wt% (C95P5R) with a good ratio of thermo-physical-mechanical properties. Additionally, the habitable cell experimental thermal behavior, with the new raffia vinifera particles and plaster-based composite as thermal insulating material for building walls, gives an average damping of 4°C and 5.8°C in the insulated house interior environment respectively for cold and hot cases compared to the outside environment and the uninsulated house interior environment. The current study highlights that this mixture gives the new composite thermal insulation properties applicable in the eco-construction of habitats in tropical environments.
文摘Burkina Faso is a malaria-endemic country, with a high incidence of G6PD deficiency (G6PDd), which recorded its first case of COVID-19 in March 2020. G6PDd leads to a decrease in the efficiency of erythrocytes to combat oxidative stress, while SARS-CoV-2 infection induces massive production of Reactive Oxygen Species (ROS) in patients. In the present review, we discuss a possible link between G6PDd and SARS-CoV-2 infection. The mean prevalence of G6PDd in Burkina Faso is estimated at 16.6% among males and 6.5% among females. A total of 21,128 cases of COVID-19 have been recorded in Burkina Faso with 387 deaths reported (with a mortality rate of 1.15% among diagnosed cases) as of August 30, 2022. To our knowledge, no association study between G6PDd and SARS-CoV-2 infection has been conducted to date in Burkina Faso. However, several case reports around the world have described elevated risks of hemolysis and thrombosis, and other complications among G6PD-deficient patients infected with SARS-CoV-2. The use of Hydroxychloroquine (HCQ) has also been deemed unsafe by some authors for the treatment of COVID-19 among patients with G6PDd. Although HCQ has been shown to be well tolerated in COVID-19 patients in Burkina Faso, the drug could induce hemolytic crises in people with G6PD deficiency. G6PD is important in regulating ROS and maintaining erythrocyte homeostasis. In view of its high prevalence in Burkina Faso, determination of the G6PD status is required in COVID-19 patients for adequate management such as identifying a subset of COVID-19 patients for whom close monitoring and supportive care may be essential and to restrict treatment with HCQ.
文摘Several fungal species are responsible for diseases that damage sesame crop and cause production losses. These seed-borne fungi cause serious damage by reducing seed germination. To identify the fungi associated with sesame seeds in Burkina Faso, 72 sesame seed samples were collected from 24 localities in the main production areas (Sudanian zone, Sudano-Sahelian zone, Sahelian zone). These samples were submitted for seed health analysis using the blotting paper incubation method. The results obtained revealed that the seed samples were contaminated by various fungi, the main ones being: Fusarium spp. Link: Fr. infecting 97.22% of the samples, Macrophomina phaseolina (Tassi) Goid. (90.28%), Alternaria sesamicola E. Kawamura (83.33%), Curvularia lunata (Wakker) Boedijn (76.39%), Cercospora sesami A. Zimmerm. (73.61%), Phoma sorghina Boerema, Dorenbosch, & Van Kesteren (73.61%), Aspergillus flavus Link: Fr. (69.44%), Cladosporium sphaerospermum Penz. (56.94%), Rhizopus sp. Ehrenb. (40.28%) and A. niger Tiegh. (36.11%). In each seed sample, 0.25% to 94% of the seeds host one or more fungal species. Regarding the climatic zones, the results revealed that A. sesamicola and A. flavus were more represented in the Sudanian zone than in the Sudano-Sahelian and Sahelian zones;while P. sorghina, and C. sphaerospermum were more encountered in the Sahelian zone than in the other two zones. This study showed that the majority of sesame seeds produced and used by farmers in Burkina Faso host one or more species of fungi at high levels.
文摘Over the past three decades, genomic and epigenetic sciences have identified more than 70 genes involved in the molecular pathophysiology of Alzheimer’s disease (AD). DNA methylation, abnormal histone and chromatin regulation and the action of various miRNAs induce AD. The identification of mutated genes has paved the way for the development of diagnostic kits and the initiation of gene therapy trials. However, despite major advances in neuroscience research, there is yet no suitable treatment for AD. Therefore, the early diagnosis of this neurodegenerative disease raises several ethical questions, including the balance between the principle of non-maleficence and the principle of beneficence. The aims of this research were to present the genomic and ethical aspects of AD, and to highlight the ethical principles involved in its presymptomatic diagnosis and therapy. A systematic review of the literature in PubMed, Google Scholar and Science Direct was carried out to outline the genomic aspects and ethical principles relating not only to the presymptomatic diagnosis of AD, but also to its gene therapy. A total of 16 publications were selected. AD is a multifactorial disease that can be genetically classified into Sporadic Alzheimer’s Disease and Familial Alzheimer’s Disease based on family history. Gene therapy targeting specific disease-causing genes is a promising therapeutic strategy. Advancements in artificial intelligence applications may enable the prediction of AD onset several years in advance. While early diagnosis of AD may empower patients with full decision competence for early decision-making, it also carries implications for the patient’s family members, who are at risk of developing the disease, potentially becoming a source of confusion or anxiety. AD has a significant impact on the life of individuals at risk and their families. Given the absence of disease modifying therapy, genetic screening and early diagnosis for this condition raise ethical issues that must be carefully considered in the context of fundamental bioethical principles, including autonomy, beneficence, non-maleficence, and justice.
文摘Background and Aim: Sarcocephalus latifolius is a medicinal plant commonly used in traditional medicine to treat various diseases. The aim of the present study is to evaluate the hepatoprotective activity of Sarcocephalus latifolius fruits aqueous extract against paracetamol-induced liver damage in rats. Material and Methods: Aqueous extract of Sarcocephalus latifolius fruits at doses of 100, 250 and 500 mg/kg were administered orally to rats with paracetamol-induced hepatotoxicity (1 g/kg). The treatment with the extract and paracetamol lasted 7 days. Silymarin (50 mg/kg) was given as reference control. All tested drugs were administered orally. Results: Our results show that the Sarcocephalus latifolius fruits extract induced a significant reduction (p < 0.05) of serum enzymes alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), alkaline phosphatase (PAL) and total bilirubin (TB). Then, the extract at the dose of 500 mg/kg showed a better protection (p < 0.001) of hepatocytes with a percentage of protection of 43.59% ± 2.03%;59.43% ± 4.12%;73.29% ± 5.72% and 62.55% ± 7.48% for ALAT, ASAT, PAL and TB, respectively. The histology of livers exposed to paracetamol shows an inflammation of the hepatocytes. In addition, there was a significant alteration of the liver parenchyma. The 500 mg/kg extract showed a resorption of the inflammation. Histopathological examination showed that the extract regenerated paracetamol-induced liver damage. Conclusion: Aqueous extract of Sarcocephalus latifolius fruits has hepatoprotective activity against paracetamol-induced hepatotoxicity in rats. But it would be important to evaluate the activity of aqueous extract of Sarcocephalus latifolius fruits on oxidative stress parameters in vivo in rats. .
文摘From November 2020 to August 2022, the diet of 12 fish species from the Samandeni reservoir was examined in order to describe the diet and the trophic level of each of them. The analysis of this vital function allows a better knowledge of the concerned ecosystem and gives opportunity for its better management. The fish were sampled with gill nets and cast net. A total of 213 stomach contents of individuals belonging to 12 species grouped in 7 families and 10 genera were analysed. Results showed low to medium vacuity coefficients. The preys were mainly composed of fish, insects, detritus, zooplankton and phytoplankton. Variability in the use of resources by individuals was evident. Thus, the 12 species were classified as fish-eating predators, granivorous, zooplanktivorous, insectivorous and filter-feeding microphages. Then, the fish trophic structure of the Samandeni reservoir was elaborated.
文摘Introduction: Hepatic diseases comprise inflammations of the liver, which can originate from drug-induced, toxic, autoimmune sources and particularly hepatitis B and C virus infection. The outcome of the disease is linked to interactions between the immune system and the virus, and also depends on the age and immune status of the patient. The aim of this study was to evaluate the association of a MAP3K14 (rs2074292), CD40 (rs1883832) polymorphism and chronic hepatitis B virus carriage in a population from Burkina Faso. Methods: In this case-control analysis, 223 and 173 samples, consisting of 90 and 53 controls and 133 and 120 cases, were examined for MAP3K14 and CD40 respectively. The cases included patients with Chronic Hepatitis B (CHB), cirrhosis or hepatocellular carcinoma (HCC). Genomic DNA extraction was executed using INVITROGEN and FAVORGEN kits. Genotyping of MAP3K14 (rs2074292) and CD40 (rs1883832) gene polymorphisms was accomplished via real-time PCR on the QuantStudioTM 5 Real-Time instrument, followed by allelic discrimination using TaqMan Genotyper Software. Data was interpreted using SPSS version 20 and Epi info version 7.5.2.0. Odds ratios (OR), confidence intervals (CI), and p-values were derived for risk and significance evaluation. Results: This study showed that the heterozygous CT genotype and the mutated T allele of the CD40 (rs1883832) gene are involved in the progression of chronic hepatitis to cirrhosis and hepatocellular carcinoma in HBV-infected patients. However, no association was found between polymorphisms in the MAP3K14 gene (rs2074292) and the progression of HBV infection. By combining the two polymorphisms, we observed either high risk or protection, depending on the genotypes of the MAP3K14 and CD40 genes simultaneously carried by the patient. Conclusion: Polymorphisms of the MAP3K14 and CD40 genes are associated with the evolution of HBV infection.
文摘The multiplication of heavy vehicle axles and road overloads are phenomena that are becoming increasingly important on the road network of the WAEMU community. These phenomena, although framed by standards, have an impact on the durability of pavements. In this manuscript it is a question of evaluating the life of the road under the effect of traffic of these multi-axle vehicles and the different tolerances of overloads observed on the road network. To achieve this, a modeling of a bituminous pavement was made with the software ALIZE Lcpc Version 231 based on the principle of the French method of sizing. An inventory of multi-axle heavy goods vehicles was also made on a road with a weighing station. This traffic counting made it possible to classify heavy goods vehicles into three categories, namely: 1) trucks, 2) dual-wheeled semi-trailers and 3) single-wheeled semi-trailers. The results obtained show that in terms of aggressiveness, single-wheeled semi-trailers are the most aggressive, followed by heavy goods vehicles in the category of trucks with more than five axles and semi-trailers with dual wheels with more than seven axles. The durability of the road depends on the aggressiveness of heavy goods vehicles, it was found that the tolerance threshold for overloads of 15% of the total permissible rolling weight (TARW) or the total permissible laden weight (TALW) currently granted in the Community area needs to be reviewed. For durable road surfaces, this tolerance may only be allowed for heavy goods vehicles of type P11, P12 and P13. The 5% tolerance can be applied to all vehicles except heavy goods vehicles with single wheels.
文摘The paper designed a non-contact system in order to perform the application (on a runway) of the Global Reporting Format (GRF) developed by International Civil Aviation Organization (ICAO). The system involves devices that film the surface (a runway in our case) from the air and displays the contaminant (water) body and measures the depth of the water automatically during the inspection. While measuring, data are sent to a computer used as a receiver. The developed devices are automatic devices implemented specially to use during rainy weather or even for some other cases. The aerial system uses a raspberry pi 4 model B, a camera, a laser sensor, an ultrasonic module, a Virtual Network Computing (VNC) and python codes developed by the authors. Results obtained show that using these devices to retrieve the Runway Condition Report (RCR) is very fast and human presence on the runway is not needed. The results obtained using these devices show that the method used herein is a proper solution to the GRF issues in the rainy areas, where the contaminant body detection and the accurate depth measurement were not well estimated because of the lack of a suitable method.
文摘Highly turbulent environment, the solar wind is a stream of very energetic particles mainly made of protons and electrons. During its trip in the interplanetary space, this solar flow becomes more accelerated during the outer minima (descending phases) of the solar cycles and can therefore influence all of humanity and its technology. These disturbances lead to socio-economic consequences requiring a precise knowledge of the climate variability. Using a statistical approach, we evaluate the response of the Earth’s magnetosphere to the High-Speed Solar Winds (HSSW) forcing during the peaks of the last five outer minima. To do so, 1UA data of solar wind and magnetic field parameters were extracted from OMNI browser. Analysis of the energetic solar plasma particles shows that strong geomagnetic field variations can occur even in the absence of large solar disturbances. While the normalized reconnection rate was estimated to be ~21% of the total variance of the magnetospheric variables, the upstream of the magnetic cavity was perturbed 80% of the time with large energies recorded. As a result, Earth’s magnetosphere becomes denser (i.e., more drag), which is a problem for spacecraft. Thus, the coupled solar wind-magnetosphere system follows scale-invariant dynamics and is in a state far from equilibrium. Our analysis provides insight into the main cause of geomagnetic storms with more than 97% of HSSW imposed in the range 300 - 850 km/s. These high-speeds lead to auroras that can disrupt electrical and communication systems.
文摘In this paper we report on the foF2 variabilities for two equatorial regions (Ouagadougou: Lat. 12.4°N;Long. 358.5°E, Dip. 1.43°S;and Manila: Lat. 14°36'15.12''N;Long. 120°58'55.92''E;Dip. 0.6°S) during solar cycles 20 and 21 minima and maxima phases. Many previous works have argued on the diurnal and seasonal variation of foF2 for different solar events conditions for latitudinal position. But there are few investigations for Africa equatorial region longitudinal variation. The present paper’s goal is to outline possible similarity in foF2 behavior between variations for better understanding of physical process lead to some observed phenomenon in Asia-Africa equatorial sector. The F-layer critical frequency (foF2) data observed from the two equatorial ionosonde stations have been used for the present comparative study. The results show significant similarity between the critical frequency (foF2) seasonal variations over the time intervals 1976-1996. During day-time measured data from Manila station are higher than those from Ouagadougou station. That may lie in that Manila is closer to equatorial ionization crest region. During solar minimum phase, the longitudinal variation of foF2 shows two crossing points (11:00 UT and 22:00 UT) between the foF2 profiles form the two stations for all seasons regardless of the solar cycle. However during intense solar activity condition, the number of crossing-point between measured data from Manila and Ouagadougou stations varies by seasons and solar cycle. This phenomenon may be due to the compilations of severe activities (storms, coronal mass ejection, heliosheet fluctuations) during the solar maximum phases.
文摘This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried out from the two nearest days (previous and following of quietest day). The study uses International Reference Ionosphere (IRI) for ionosphere modeling. The located station is Ouagadougou, in West Africa. Solar minimum of phase 22 is considered in this study. Using three core principles of ionosphere modeling under IRI running conditions, the study enables to carry out Peak of electron density in F2-layer values during the quietest days of the characteristic months for the four different seasons. These parameters are compared to those of the previous and the following of the quietest days (the day before and following each quietest selected day) at the same hour. The knowledge of NmF2 values at the quietest days and at the two nearest days enables to calculate the relative error that can be made on this parameter. This calculation highlights insignificant relative errors. This means that NmF2 values at the two nearest days of each quietest day on solar minimum can be used for simulating the quietest days’ behavior. NmF2 values obtained by running IRI model have good correlation with those carried out by Thermosphere-Ionosphere-Electrodynamics-General Circulation Model (TIEGCM).
文摘In this study, the authors investigated the performance of different buffer layers through the electrical parameters such as J<sub>sc</sub>, V<sub>oc</sub>, QE and η of the quaternary system Cu(In,Ga)Se<sub>2</sub> solar cells. The performance of Cu(In,Ga)Se<sub>2</sub>solar cells has been modeled and numerically simulated by using the SCAPS- 1D device simulation tool. The cells with a ZnSe, Zn(O,S) and (Zn,Mg)O buffer layers were compared with the reference CdS buffer layer. The investigation of ZnSe, Zn(O, S) and (Zn,Mg)O-based cells to substitute the traditional CdS in the future shows that the ZnSe-buffer layer is a potential material to replace CdS, which revealed the best efficiency of 20.76%, the other electrical parameters are: J<sub>SC</sub> = 34.6 mA/cm<sup>2</sup>, V<sub>OC</sub> = 0.76 V and FF = 79.6%. The losses as a function of the temperature are estimated at 0.1%/K, among all kinds of buffer layers studied. We have also shown that the use of a high band-gap buffer layer is necessary to obtain a better short-circuit current density J<sub>SC</sub>. From our results, we note that the chalcogenide solar cells with Zn-based alternative buffer layer have almost the same stability thatthe traditional CdS buffer layer solar cells have.
文摘Ionosphere parameters determination is used to characterize its composition in particles. These results have been compared to data curried from Ouagadougou station. The present study deals with Total Electron Contents (TEC) results determined by Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) version 1.94 and International Reference Ionosphere (IRI) version 2012 during solar cycle 22. The minimum and maximum phases of solar cycle 22 are considered in this study for TEC determination. The station is located at Ouagadougou, in western Africa, characterized by its latitude (12.4°N) and longitude (358.5°E). The present study completes the two previous articles on hmF2 and foF2 parameters determination on the same station by comparison between TEC results carried out from TIEGCM and IRI models. So that, quiet time condition is determined by Aa (≤20 nT) for the five quietest days in each characteristic month of seasons. Rz values characterize minimum and maximum solar cycle phases.
