Construire une question de recherche dans l’interdisciplinarité Building an Interdisciplinary Research Question

Interdisciplinarity is strongly promoted by institutions and is the subject of abundant scientific publications on its history,definition,and typologies,as well as on its obstacles and challenges.This article aims to provide insight into the development of an interdisciplinary research question.We will present the path that led from an administrative management question to a doctorate in philosophy of medicine on supportive care,thanks to a rich collaboration between a wide range of academic,hospital,and association players.An analysis of the literature will show how the long history of science underpins disciplinary issues in the development of a research question.The method will make visible the long dialogue between the partners in this project.The results will show how the research question evolved throughout the project.Finally,the discussion will propose three concepts to put interdisciplinarity into perspective:collaboration,attention,and tranquility.

Estimation of Landfill Gas and Its Renewable Energy Potential from the Polesgo Controlled Landfill Using First-Order Decay (FOD) Models

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.

Molecular Diagnosis of Sexual Differentiation Disorders in Burkina Faso

Sex development anomalies represent a group of congenital pathologies in which chromosomal, gonadal and anatomical sex differentiation is atypical. The aim of our study was to use molecular biology techniques to elucidate sex in cases of anomalies of sexual differentiation in Burkina Faso. This cross-sectional study took place from March 2023 to June 2023. Oral and blood samples were collected respectively using sterile swabs and stored on Swab Kits and NUCLEIcardTM (https://www.copangroup.com/product-ranges/nucleic-card/) were used to determine gonosome profiles. Extraction was carried out using the DNA Swap solution Kit and the DNA IQ System Kit, and a PowerPlex? 21 kit (Promega) for amplification. The Applied Biosystems 9700 thermal cycler was used for PCR followed by 36 cm capillary electrophoresis in the Applied Biosystems 3130 prism sequencer. Sequence files were analyzed using GeneMapper IDX v. 3.2 software. Seven (07) patients were registered during the study period. There were 4 cases of XX DSD or 46, XX DSD and 3 cases of XY DSD or 46, XY DSD. The median age of our patients was 16 years. Civilian sex was male in 4 cases and female in 3. The most frequent reason for consultation was micropenis in 3 cases, followed by primary amenorrhea and sex ambiguity. There were 03 cases of discrepancy between genetic sex and civil sex. The accessibility of molecular diagnosis is little known to clinicians. XX DSDs or 46, XX DSDs were the most frequent (4/7) in our study. The problem facing this situation is early diagnosis to help prevent complications in Burkina Faso.

New insights into intergeneric relationships of Hickeliinae(Poaceae:Bambusoideae) revealed by complete plastid genomes

The Hickeliinae(Poaceae:Bambusoideae) is an ecologically and economically significant subtribe of tropical bamboos restricted to Madagascar,Comoros,Reunion Island,and a small part of continental Africa(Tanzania).Because these bamboos rarely flower,field identification is challenging,and inferring the evolutionary history of Hickeliinae from herbarium specimens is even more so.Molecular phylogenetic work is critical to understanding this group of bamboos.Here,comparative analysis of 22 newly sequenced plastid genomes showed that members of all genera of Hickeliinae share evolutionarily conserved plastome structures.We also determined that Hickeliinae plastome sequences are informative for phylogenetic reconstructions.Phylogenetic analysis showed that all genera of Hickeliinae are monophyletic,except for Nastus,which is paraphyletic and forms two distant clades.The type species of Nastus(Clade Ⅱ) is endemic to Reunion Island and is not closely related to other sampled species of Nastus endemic to Madagascar(Clade Ⅵ).Clade Ⅵ(Malagasy Nastus) is sister to the Sokinochloa+Hitchcockella clade(Clade Ⅴ),and both clades have a clumping habit with short-necked pachymorph rhizomes.The monotypic Decaryochloa is remarkable in having the longest floret in Bambuseae and forms a distinct Clade Ⅳ.Clade Ⅲ,which has the highest generic diversity,consists of Cathariostachys,Perrierbambus,Sirochloa,and Valiha,which are also morphologically diverse.This work provides significant resources for further genetic and phylogenomic studies of Hickeliinae,an understudied subtribe of bamboo.

Phytochemical Profile, Antioxidant, and Anti-Inflammatory Activities, Safety of Use and Spasmolytic Effects of Aqueous Decoction Extract of Diospyros mespiliformis Leaves Hochst. ex A. DC. (Ebenaceae) on the Isolated Duodenum of Rat

Diospyros mespiliformis Hochst. ex A. DC. (Ebenaceae) is a multi-use plant, including for therapeutic purposes. It is used in alternative medicine in Burkina Faso to treat conjunctivitis, menorrhagia, dysentery, and diarrhea. The aim of our study was to evaluate the chemical profile, antioxidant and anti-inflammatory activities, safety of use and spasmolytic effects of the aqueous decoction of Diospyros mespiliformis leaves. Phytochemical screening by HPTLC and assay of compounds of interest were carried out. Four methods were used to assess antioxidant activity. Inhibitory activity against 15-lipoxygenase and phospholipase A2 was assessed. Acute oral toxicity of the extract was tested on female mice (NMRI). Following these tests, the extract contained bioactive compounds of interest such as flavonoids, tannins, sterols, triterpenes, and saponosides. The total phenolic and flavonoid contents of the aqueous decoctate were 70.59 ± 3.20 mg EAT/g and 31.57 ± 0.78 mg EQ/g respectively. The extract was less active than Trolox with inhibitory concentrations of 50% (IC50) for the ABTS, DPPH, FRAP, and LPO tests of 7.53 ± 0.08 μg/mL, 29.47 ± 0.06 μg/mL, 1128.83 ± 4.82 mol EAA/g, and 32.30 ± 1.60 μg/mL respectively. The extract has an anti-inflammatory effect with inhibition of phospholipase A2 compared to betamethasone. In addition, the aqueous extract produced an antispasmodic effect with Emax of 70% and 80% respectively during contractions induced by BaCl2 and ACh. Finally, this study provided basic scientific data and could justify the use of D. mespiliformis leaves in the treatment of diarrhea.

Hygrothermal Study of a House Made of Local Biosourced Materials Based on Clay: Experimental Study

The purpose of this study is to experimentally analyze the thermal behavior of the walls of a prototype experimental house. A Datalogger and thermocouples were used on the experimental house to determine the temperatures of the exterior and interior walls. Also, “MSR” type HygroPuce was used to determine the exterior and interior temperatures and relative humidity of the habitat. The results show that a wall made of bio-based materials with a mixture of “earth + Hibiscus cannabinus L. fibers” allows reducing the fluctuations of the interior temperatures. We observe the peaks of temperatures on the external walls at 11:00 am and for the interior walls, the peaks are observed at 5:00 pm. The maximum thermal phase shift between the peaks of the external and internal temperatures is about 7.5 hours, and the maximum damping factor is 0.9. Also, we note that the thermal performance of the material used in the design of the envelope of the house is determined by the improvement of the response of the envelope in front of the external thermal solicitations.

Associations between physical activity levels and ATPase inhibitory factor 1 concentrations in older adults

Background:Adenosine triphosphatase inhibitory factor 1(IF1)is a key protein involved in energy metabolism.IF1 has been linked to various agerelated diseases,although its relationship with physical activity(PA)remains unclear.Additionally,the apolipoprotein A-I(apoA-I),a PA-modulated lipoprotein,could play a role in this relationship because it shares a binding site with IF1 on the cell-surface ATP synthase.We examined here the associations between chronic PA and plasma IF1 concentrations among older adults,and we investigated whether apoA-I mediated these associations.Methods:In the present work,1096 healthy adults(63.8%females)aged 70 years and over who were involved in the Multidomain Alzheimer Prevention Trial study were included.IF1 plasma concentrations(square root of ng/mL)were measured at the 1-year visit of the Multidomain Alzheimer Prevention Trial,while PA levels(square root of metabolic equivalent task min/week)were assessed using questionnaires administered each year from baseline to the 3-year visit.Multiple linear regressions were performed to investigate the associations between the first-year mean PA levels and IF1 concentrations.Mediation analyses were conducted to examine whether apoA-I mediated these associations.Mixedeffect linear regressions were carried out to investigate whether the 1-year visit IF1 concentrations predicted subsequent changes in PA.Results:Multiple linear regressions indicated that first-year mean PA levels were positively associated with IF1 concentrations(B=0.021;SE=0.010;p=0.043).Mediation analyses revealed that about 37.7%of this relationship was mediated by apoA-I(B_(ab)=0.008;SE=0.004;p=0.023).Longitudinal investigations demonstrated that higher concentrations of IF1 at the 1-year visit predicted a faster decline in PA levels over the subsequent 2 years(time×IF1:B=0.148;SE=0.066;p=0.025).Conclusion:This study demonstrates that regular PA is associated with plasma IF1 concentrations,and it suggests that apoA-I partly mediates this association.Additionally,this study finds that baseline concentrations of IF1 can predict future changes in PA.However,further research is needed to fully understand the mechanisms underlying these observations.

Evaluation of a Rapid Diagnostic Test, Boson Biotech SARS CoV-2 Ag, for the Detection of SARS-CoV-2 in Gabon

1) Background: Rapid and acurate diagnostic testing for case identification, quarantine, and contact tracing is essential for managing the COVID 19 pandemic. Rapid antigen detection tests are available, however, it is important to evaluate their performances before use. We tested a rapid antigen detection of SARS-CoV-2, based on the immunochromatography (Boson Biotech SARS-CoV-2 Ag Test (Xiamen Boson Biotech Co., Ltd., China)) and the results were compared with the real time reverse transcriptase-Polymerase chain reaction (RT-PCR) (Gold standard) results;2) Methods: From November 2021 to December 2021, samples were collected from symptomatic patients and asymptomatic individuals referred for testing in a hospital during the second pandemic wave in Gabon. All these participants attending “CTA Angondjé”, a field hospital set up as part of the management of COVID-19 in Gabon. Two nasopharyngeal swabs were collected in all the patients, one for Ag test and the other for RT-PCR;3) Results: A total of 300 samples were collected from 189 symptomatic and 111 asymptomatic individuals. The sensitivity and specificity of the antigen test were 82.5% [95%CI 73.8 - 89.3] and 97.9 % [95%CI 92.2 - 98.2] respectively, and the diagnostic accuracy was 84.4% (95% CI: 79.8 - 88.3%). The antigen test was more likely to be positive for samples with RT-PCR Ct values ≤ 32, with a sensitivity of 89.8%;4) Conclusions: The Boson Biotech SARS-CoV-2 Ag Test has good sensitivity and can detect SARS-CoV-2 infection, especially among symptomatic individuals with low viral load. This test could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and curb viral transmission.

Case Study for Undetermined Mosquito Species by Polymerase Chain Reaction in Western Burkina Faso

Introduction: Malaria eradication campaigns all over the world are largely based on parasite and vector control. Vector identification, whether morphological or molecular, is an essential component of vector control. This study analyzed the possible causes of indeterminate polymerase chain reaction (PCR) results for mosquito species in Western part of Burkina Faso. Methodology: From July 2021 to November 2021, mosquitoes were collected during the period of high malaria transmission in the village of Séguéré, Houet province, Burkina Faso, and morphologically identified. After DNA extraction, samples were amplified by sine 200× PCR to identify species of the Anopheles gambiae complex. Indeterminate samples were then selected for further analysis. The parameters studied were: DNA dilution, the effect of protocol adjusting, and the type of protocol used. Results: A total of 130 “indeterminate” DNAs diluted 1:10 were analyzed. After dilution, the mean amount was 14.73 ± 3.59 ng/μL and absorbance 1.71 ± 0.1. PCR chain reaction yielded 94.62% (123/130) anopheline species in SINE PCR, 5.38% (7/130) “negative”. A significant difference between SINE PCR before dilution and after dilution was observed (P < 0.001). Identification tests carried out using other protocols gave no positive results. From these results, we note that the adaptation of the protocol significantly reduced the polymerase amplification results of the species. Conclusion: It is therefore necessary to respect the amplification protocols. However, the persistence of “indeterminate” results suggests that further studies should be carried out to shed more light on the subject.

Antibacterial, Anti-Inflammatory and Antioxidant Activities of an ACAZY Herbal Formula Used in Traditional Medicine to Treat Respiratory Infections

ACAZY is a plant formula used in traditional medicine in Burkina Faso to treat respiratory infections. After phytochemical analysis, this study evaluated extracts’ anti-inflammatory, antioxidant and antibacterial properties from the ACAZY recipe. Three extractions, an aqueous macerate (AM), an aqueous decoction (AD) and an hydroethanolic macerate (HEM) of the ACAZY recipe powder were carried out. Phytochemical screening of the extracts was carried out using high-performance thin-layer chromatography (HPTLC) and the determination of phenolic compounds. The anti-inflammatory potential was assessed in vitro using pro-inflammatory enzyme inhibition tests. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and Ferric-reducing antioxidant power (FRAP) antioxidant properties were also determined. The antibacterial activity was evaluated on Staphylococcus aureus and Streptococcus pneumoniae strains. Phytochemical analysis revealed the presence of flavonoids, saponins, tannins, anthracenosids, sterols and triterpenes in the extracts. The extracts inhibited pro-inflammatory enzymes by more than 40% at only 100 µg/mL. The extracts also showed potent antibacterial activity with a minimum inhibitory concentration 1 mg/mL on Staphylococcus aureus and 2 mg/mL on Streptococcus pneumoniae. The extracts in the ACAZY formula have shown anti-inflammatory and antioxidant properties in vitro. The AD also showed an antibacterial activity. This justifies its use in traditional medicine to treat acute respiratory infections.

Identification of Bacteria Strains Isolated in Urinary Tract Infections and Their Antibiotic Susceptibility at the National Public Health Laboratory, Ouagadougou

Background: Urinary tract infections are still a real public health concern. The aim of this study was to identify the bacteria strains involved in urinary tract infections and to determine their antibiotic resistance profiles. Methods: Two kinds of studies were performed. The retrospective study was carried out for 2 years (from January 2018 to December 2019), and the prospective study was extended over a period of 6 months (from January to June 2020). Isolation and identification of bacteria strains were performed using conventional microbiology techniques. The strains’ resistance profiles were determined by the diffusion method on Mueller-Hinton according to the criteria of EUCAST- 2015. Fourteen (14) antibiotic discs were used depending on the isolated germ. Results: A total of 187 bacterial strains were isolated from 82 men and 105 women. Among the germs identified, 77.54% were Enterobacteriaceae and 13.36% were cocci strains. Non-fermentative gram-negative bacilli accounted for 9.08% of the isolated bacteria. The results showed that the majority of Enterobacteriaceae strains were resistant to beta-lactams: 100% to amoxicillin, 98.75% to amoxicillin + clavulanic acid, 41.76% to ceftriaxone, and 43.14% to ceftazidime. These findings were obtained with fluoroquinolones and aminoglycosides: 50.09% with ciprofloxacin, 54.04% with norfloxacin, and 22.58% with amikacin. 8.75% of the Enterobacteriaceae strains tested were resistant to imipenem. The same trends were observed with non-fer- mentative bacteria. As for the gram-positive bacteria isolated during our study, 13.33% were resistant to vancomycin, 21.05% to gentamicin, 94.12% to penicillin G, 88.89% to ampicillin, 77.78% to cefotaxime, 63.63% to kanamycin, and 52.63% to erythromycin. Conclusion: This study revealed, as in other studies, that Enterobacteriaceae strains remain the most incriminated bacteria strains in urinary tract infections, with a strong resistance to antibiotics. It is important that actions be taken to reduce the incidence of urinary tract infections and mitigate the spread of resistant bacteria.

Performance Evaluation of Solar Chimney Draft: Application to Ventilation

Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.

Role of 3'-untranslated region translational control in cancer development, diagnostics and treatment

The messenger RNA 3'-untranslated region(3'UTR)plays an important role in regulation of gene expres-sion on the posttranscriptional level. The 3'UTR con-trols gene expression via orchestrated interactionbetween the structural components of mRNAs(cis-ele-ment) and the specific trans-acting factors(RNA bind-ing proteins and non-coding RNAs). The crosstalk ofthese factors is based on the binding sequences and/or direct protein-protein interaction, or just functionalinteraction. Much new evidence that has accumulatedsupports the idea that several RNA binding factors canbind to common mRNA targets: to the non-overlappingbinding sites or to common sites in a competitive fash-ion. Various factors capable of binding to the sameRNA can cooperate or be antagonistic in their actions.The outcome of the collective function of all factorsbound to the same mRNA 3'UTR depends on manycircumstances, such as their expression levels, affinity to the binding sites, and localization in the cell, which can be controlled by various physiological conditions. Moreover, the functional and/or physical interactions of the factors binding to 3'UTR can change the character of their actions. These interactions vary during the cell cycle and in response to changing physiological condi-tions. Abnormal functioning of the factors can lead to disease. In this review we will discuss how alterations of these factors or their interaction can affect cancer development and promote or enhance the malignant phenotype of cancer cells. Understanding these altera-tions and their impact on 3'UTR-directed posttran-scriptional gene regulation will uncover promising new targets for therapeutic intervention and diagnostics. We will also discuss emerging new tools in cancer di-agnostics and therapy based on 3'UTR binding factors and approaches to improve them.

Fire temperature and residence time during dry season burning in a Sudanian savanna-woodland of West Africa with implication for seed germination

Prescribed fire is used in the Sudanian savanna-woodland of West Africa as a forest management tool. An experiment was carried out to assess the effects of season of burning, and different vertical probe positions on maximum fire temperature and temperature residence time above 60℃ which is considered lethal for plant tissues. Seasons of burning considered were： an early season fire set at the beginning of the dry season （beginning of December）, mid-season fire set at the peak of the dry season （mid-January）, and a late season fire at the end of the dry season （end of March）. The effects of these fires on the germination of buried seeds of three socio-economically valuable tree species were also examined. Results indicated significant differences in maximum fire temperature and residence time with respect to season of burning and vertical probe position （p 〈 0.001）. The highest and longest lasting temperatures were observed at 20 cm above ground during early fire and at the soil surface during mid-season and late fires. This, in turn, affected germination responses of seeds buried at different soil depths. Implications of these findings in the current management practices are discussed.

Tubulin glutamylation: a skeleton key for neurodegenerative diseases

Microtubules (MTs) are cytoskeletal elements formed by a non-covalent association of α- and β-tubulin heterodimers. They provide structure and shape to all eukaryotic cells and are implicated in a variety of fundamental cellular processes including cell motility, cell division, mechanotransduction as well as long-distance intracellular cargo transport. In neurons, they constitute the molecular frame that maintains the lengthy axonal projections. In view of the relative size of some axons in the human body, which can reach up to 1 m, the active transport of e.g., vesicles over the MT arrays to the synaptic cleft, is of particular importance.

Peak of Electron Density in F2-Layer Parameters Variability at Quiet Days on Solar Minimum

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).

Impact of Annealing Treatment on the Behaviour of Titanium Dioxide Nanotube Layers

In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs to be better understood. Nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis, coupled with thermogravimetry, gives us an inside on the oxidation behaviour of titanium dioxide nanotube layers compared to bulk reference samples. Structural studies were performed at 700°C for 12 h in order to follow the time consequences on the oxidation of the material, in sufficient stability conditions. In-situ XRD brought to light that the amorphous oxide layer induced by anodization is responsible for the simultaneous growths of anatase and rutile phase during the first 30 minutes of annealing while the bulk sample oxidation leads to the nucleation of a small amount of anatase TiO2. The initial amorphous oxide layer created by anodization is also responsible for the delay in crystallization compared to the bulk sample. Thermogravimetric analysis exhibits parabolic shape of the mass gain for both anodized and bulk sample;this kinetics is caused by the formation of a rutile external protective layer, as depicted by the associated in-situ XRD diffractograms. We recorded that titanium dioxide nanotube layers exhibit a lower mean mass gain than the bulk, because of the presence of an initial amorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layers behavior during the annealing treatment for the bulk and nanostructured layer. Anatase crystallites are mainly localized at the interface oxide layer-metal and the rutile is at the external interface. Sample surface topography was characterized using scanning electron microscopy (SEM). As a probe of the photoactivity of the annealed TiO2 nanotube layers, degradation of an acid orange 7 (AO7) dye solution and 4-chlorophenol under UV irradiation (at 365 nm) were performed. Such titanium dioxide nanotube layers show an efficient photocatalytic activity and the analytical results confirm the degradation mechanism of the 4-chlorophenol reported elsewhere.

Electron Bulk Surface Density Effect on Critical Frequency in the F2-Layer

Ionosphere layer is the atmosphere region which reflects radio waves for telecommunication. The density in particles in this layer influences the quality of communication. This study deals with the effects of Total Electron Contents (TEC) on the critical frequency of radio waves in the F2-layer. Total Electron Contents parameter symbolizes electron bulk surface density in ionosphere layer. Above critical frequency value in F2 layer (foF2), radio waves pass through ionosphere. The knowledge of this value enables to calibrate transmission frequencies. In this study, we consider TEC effects on foF2 under quiet time conditions during the maximum and the minimum of solar cycle 22, at Ouagadougou station, in West Africa. The study also considers the effects of seasons and the hourly variability of TEC and foF2. This work shows winter anomaly on foF2 and TEC on minimum and maximum of solar cycle phase respectively. Running International Reference Ionosphere (IRI) model enables to carry out the effects of TEC on foF2 by use of their monthly average values. This leads to a new approach to calibrate radio transmitters.

Simulation and Evaluation of Dust Emission with Polair3D-SIREAM Model over West Africa Focused on Ouagadougou (Burkina Faso)

The study of air pollution is recent in West Africa. There is a lack of data on air pollution. However, some studies conducted in West Africa show that air quality is a concern. Population growth and massive vehicles imports are contributing to the deterioration of this air quality. In this work, we present the modelling of desert aerosols using a CTM Polair3D-SIREAM. The objective is to evaluate the ability of Polair3D-SIREAM to reproduce observations of PM10 and Aerosol Optical Thicknesses (AOT). A simulation with Polair3D-SIREAM was carried out in West Africa, focused on Ouagadougou (Burkina Faso) for 2007. The model of Marticorena and Bergametti (1995), MB95, was used to estimate desert aerosols emissions. The total emission of dust modelled is 52.2 Tg. For the evaluation of PM10, the simulated averages remained within the same orders of magnitude as the observed averages. Correlations are low in all the observation sites. The other indicators are similar to those found by Schmechtig et al. (2011). Performance criteria of Boylan and Russel (2006) are met for the observation sites of Ouagadougou and Ilorin (Nigeria). For the AOTs, the correlations are significantly improved, in particular, at the sites of Ouagadougou and Ilorin. Performance criteria of Boylan are met for all observation sites. However, the performance goals are only achieved for Ouagadougou and Ilorin.

Assessment of Pollution Levels of Suspended Particulate Matter on an Hourly and a Daily Time Scale in West African Cities: Case Study of Ouagadougou (Burkina Faso)

In Western countries, research works on air quality have reinforced in recent years because of the links between the level of particulate pollution in numerous cities and the appearing of various health disorders including cardio-respiratory pathologies, acute bronchopneumonia, lung cancer, etc. In sub-Saharan Africa countries, particularly Burkina Faso, there is very few similar research. In the present work, the pollution levels of airborne particle in the city of Ouagadougou have been assessed through two campaigns of in situ measurements of suspended particulate matter concentrations. These measurements which have concerned PM1, PM2.5 and PM10 were performed using a portable device (AEROCET531S) at nine sites in 2018 and at ten sites in 2019. These sites are located on roadside, administrative services, secondary education establishments and outlying districts. The results show that: 1) the PM1 concentrations values presented no significant variation between days, seasons or sampling sites;2) the 24-hour PM2.5 concentrations often exceeding WHO recommended concentrations and, 3) the 24-hour PM10 concentrations exceed WHO recommended concentrations regardless of the season or the sampling site. In indeed, the average 24-hour concentrations are 20 ± 4, 87 ± 16 and 951 ± 266 μg·m−3 for the PM1, PM2.5 and PM10, respectively. They are 17 ± 3, 29 ± 5 and 158 ± 43 μg·m−3, respectively, in 2018 dry season and, 12 ± 1, 22 ± 9 and 187 ± 67 μg·m−3, respectively, in 2019 rainy season.