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Search Results: 1 - 10 of 379 matches for " Ousmane Sarr "
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Optimization and Modeling of Antireflective Layers for Silicon Solar Cells: In Search of Optimal Materials  [PDF]
Mamadou Moustapha Diop, Alassane Diaw, Nacire Mbengue, Ousmane Ba, Moulaye Diagne, Oumar A. Niasse, Bassirou Ba, Joseph Sarr
Materials Sciences and Applications (MSA) , 2018, DOI: 10.4236/msa.2018.98051
Abstract: Depositing an antireflection coating on the front surface of solar cells allows a significant reduction in reflection losses. It thus allows an increase in the efficiency of the cells. A modeling of the refractive indices and the thicknesses of an optimal antireflection coating has been proposed. Thus, the average reflective losses can be reduced to less than 8% and less than 2.4% in a large wavelength range respectively for a single-layer and double-layer anti-reflective coating types. However, the difficulty of finding these model materials (materials with the same refractive index) led us to introduce two notions: the refractive index difference and the thickness difference. These two notions allowed us to compare the reflectivity of the antireflection layer in silicon surface. Thus, the lower the refractive index difference is, the more the material resembles to the ideal material (in refractive index), and thus its reflective losses are minimal. SiNx and SiO2/TiO2 antireflection layers, in the wavelength range between 400 and 1100 nm, have reduced the average reflectivity losses to less than 9% and 2.3% respectively.
Infrared and UV-Vis studies of copper(II) complexes of 3,6-bis((saliclidenamino)ethyl)- sulfanylpyridazine
Mohamed Gaye,Oumar Sarr,Abdou Salam Sall,Ousmane Diouf
Bulletin of the Chemical Society of Ethiopia , 1997,
Validation of a Capillary Electrophoresis Method for Analyzing Chlorphenamine Maleate-Based Drugs Using the Accuracy Profile Approach  [PDF]
Serigne Omar Sarr, Eddy Kevin Senan Ouendo, Thierno Mouhamed Wane, El Hadji Assane Diop, Diop Amadou, Serigne Momar Ndiaye, Rokhaya Gueye, Khadidiatou Thiam, Aminata Sarr, Ousmane Niass, Djibril Fall, Bara Ndiaye, Serge Rudaz, Yérim Mbagnick Diop
American Journal of Analytical Chemistry (AJAC) , 2016, DOI: 10.4236/ajac.2016.75042
Abstract: This study aimed at validating an analytical method, using the accuracy profile approach, for the assay of chlorphenamine maleate by capillary electrophoresis. The validation was done using concentrations ranging between 75% and 125% of the target concentration of 600 mg/ml. Validation standards were prepared separately in triplicate for each series. Studied validation criteria were selectivity, linearity, trueness, precision (repeatability and intermediate precision), accuracy and limits of detection and quantification. The method was selective, with recoveries ranging between 99.55% and 99.84%. The relative standard deviations of repeatability and intermediate precision were <5%. The accuracy profile confirmed the performance of the assay method between 75% and 100% of the target concentration of 600 mg/ml. The detection and quantification limits were 5 mg/l and 15 mg/l respectively. This ecological and economical method was applied to identify and quantify chlorphenamine maleate in 3 samples of chlorphenamine maleate-based drugs provided by the Senegalese National Medicines Control Laboratory. All analyzed samples were in accordance with official standards.
Modernization of Public Transports in Senegal: Case of Ticket Payment Method in Dakar Dem Dikk (3Ds) Buses  [PDF]
Sall Ousmane, Diallo Ousmane
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.67013
Abstract: Transport is one of the important keys of growth and socio-economic development for any country. Since 2005, Senegalese authorities have embarked on a vast fleet renewal program to modernize urban transport and professionalize the actors. The purpose of this paper is to sensitize people about the modernization of ticket payment method in Dakar Dem Dikk buses. To achieve this objective, a survey was done through the users and results have shown that the majority of participants agree to adopt the electronic ticketing smart card in public transport. This contactless payment technology is also recommended in commerce sector to facilitate and secure transactions.
Chinese Soft Power in Africa: Case of Senegal  [PDF]
Ousmane Sall
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.411011
Beijing political system in Africa has ostensibly made China a major leader throughout this continent. The different elements that link Africa to China have traditionally been embedded in the discourse of cooperation, mutual benefit and political equality. Then, we can notice that China is building a positive image throughout Africa. Let’s take the example of Senegal where, between 2006 and 2011, approximately 26 Chinese official development finance projects are identified. These projects are estimated around 100 millions USD financed by China’s Exim Bank [1] This endeavor not only spotlights how China is creating a favorable international environment but also it’s close to the concept of soft power. However, soft power is about dynamic relationships between an agent and the subject of attraction. China’s foreign policy and strategy is highly influential, because China’s main target is to lead the world in all fields. Two important issues within this are whether the relationship between the two parts of the world is symmetrical or asymmetrical and the exact role of soft power in this constellation. This paper is going to focus on these arguments and proposes that prominent economies on the African continent such as Senegal have an inescapable role to play in ensuring a symmetrical relationship between China and Africa.
Utilization of Health Services in the Burkina Faso Health System: Empirical Evidence of Health System Fragmentation and Integration  [PDF]
Ousmane Traoré
Modern Economy (ME) , 2016, DOI: 10.4236/me.2016.713139
In this paper, the utilization of health services in the context of health system fragmentation in Burkina Faso is analyzed using household living condition survey data. The methodology explores the relationships between population health risk factors and health services utilization. The results of the analysis highlighted eight reference care providers in the Burkina Faso health system; thus, the probability of service use in the first level of the system, assumed to be its point of entry, is significantly and negatively associated with age and sex, with a lower probability for female gender. As a whole, the health risk factors positively influence the probability of service use at the higher levels of the health system and in the private sector. The results suggest that utilization of the traditional health sector remains predominated by the elderly. These results thus suggest the need for coordination of care across the levels of the public healthcare sector, on the one hand, and the presence of interaction and integration between the traditional or private sector and the public sector, on the other hand.
Multi-Scale Characteristics of Precipitation and Temperature over West Africa Using SMHI-RCA Driven by GCMs under RCP8.5  [PDF]
Abdoulaye Sarr
American Journal of Climate Change (AJCC) , 2017, DOI: 10.4236/ajcc.2017.63024
Abstract: In this paper, we use simulations from the Swedish Meteorological and Hydrological Institute (SMHI) regional climate model (RCM) version 3.5 (SMHI-RCA3.5) following a multi-GCM boundary forcing approach. The model is run at a horizontal resolution of 50 km on the CORDEX-AFRICA domain. Key characteristics of precipitation, mean temperature and its extremes (minimum and maximum temperature) have been investigated over West Africa and on 3 designed sub-domains, the Sahel (SAH), the Senegal-Gambia (SEN) and the Gulf of Guinea (GOG). The analysis covers a historical period 1981-2005 and two future time slices, an intermediate term (IT) 2031-2055 and a fat term (FT) 2071-2095, under the Representative Concentration Pathways 8.5 (RCP8.5). The regional climate model RCA, forced by the reanalysis ERA-Interim, 6 CMIP5 GCMs and their ensemble, reproduces realistically the climatology of precipitation and temperatures over West Africa. Compared to observed datasets GPCP for precipitation and CRU for temperature, the ensemble outperforms both other GCMs and the verification model (ERA-Interim). The major biases in precipitation are the early onset over the Sahel and the little dry season (LDS), from mid-July to mid-September over the Gulf of Guinea, and a few models either overestimate and/or reflect rather poorly. The strong warming in extreme temperatures (minimum and maximum) combined with the drying mainly over Western Sahel (SEN) found in this study will very likely impact notably a vital sector like agriculture, both during the near and far terms.
Confirmation of emergence of mutations associated with atovaquone-proguanil resistance in unexposed Plasmodium falciparum isolates from Africa
Christian T Happi, Grace O Gbotosho, Onikepe A Folarin, Danny Milner, Ousmane Sarr, Akintunde Sowunmi, Dennis E Kyle, Wilbur K Milhous, Dyann F Wirth, Ayoade MJ Oduola
Malaria Journal , 2006, DOI: 10.1186/1475-2875-5-82
Abstract: The prevalence of codon-268 mutations in the cytb gene of African P. falciparum isolates from Nigeria, Malawi and Senegal, where atovaquone-proguanil has not been introduced for treatment of malaria was assessed. Genotyping of the cytb gene in isolates of P. falciparum was performed by PCR-restriction fragment length polymorphism and confirmed by sequencing.295 samples from Nigeria (111), Malawi (91) and Senegal (93) were successfully analyzed for detection of either mutant Tyr268Ser or Tyr268Asn. No case of Ser268 or Asn268 was detected in cytb gene of parasites from Malawi or Senegal. However, Asn268 was detected in five out of 111 (4.5%) unexposed P. falciparum isolates from Nigeria. In addition, one out of these five mutant Asn268 isolates showed an additional cytb mutation leading to a Pro266Thr substitution inside the ubiquinone reduction site.No Tyr268Ser mutation is found in cytb of P. falciparum isolates from Nigeria, Malawi or Senegal. This study reports for the first time cytb Tyr268Asn mutation in unexposed P. falciparum isolates from Nigeria. The emergence in Africa of P. falciparum isolates with cytb Tyr268Asn mutation is a matter of serious concern. Continuous monitoring of atovaquone-proguanil resistant P. falciparum in Africa is warranted for the rational use of this new antimalarial drug, especially in non-immune travelers.The rapid development and spread of drug resistant Plasmodium falciparum is a serious global health problem in the management of malaria infections. Increasing resistance to antimalarials by P. falciparum has led to renewed search for alternative effective new drugs with unique cellular targets. In the 1990s, the urgent need for new anti-malarial drugs for treatment and chemoprophylaxis led to the development of atovaquone (2-[trans-4-(4'-chlorophenyl) cyclohexyl]-3-hydroxy-1,4-hydroxynaphtoquinone)[1]. This anti-malarial compound has broad spectrum activity against human protozoan pathogens [2,3] among which are the Plasmodium s
In vivo transcriptional profiling of Plasmodium falciparum
Johanna P Daily, Karine G Le Roch, Ousmane Sarr, Xuemin Fang, Yingyao Zhou, Omar Ndir, Soulyemane Mboup, Ali Sultan, Elizabeth A Winzeler, Dyann F Wirth
Malaria Journal , 2004, DOI: 10.1186/1475-2875-3-30
Abstract: A custom made oligonucleotide array with probes based on the P. falciparum 3D7 laboratory strain chromosome 2 sequence was used to detect in vivo P. falciparum transcripts. This study analyzed transcripts from total RNA derived from small blood samples of P. falciparum infected patients and compared the in vivo expression profile to the in vitro cultivated 3D7 strain transcriptome.The data demonstrated that in vivo transcription can be studied from a small blood sample, despite the abundance of human RNA. The in vivo transcriptome is similar to the 3D7 ring stage transcriptome, but there are significant differences in genes encoding a sexual stage antigen and surface proteins.Whole genome transcription analysis of P. falciparum can be carried out successfully and further studies in selected patient cohorts may provide insight into parasite in vivo biology and defense against host immunity.Plasmodium falciparum infection remains a major health problem worldwide. Its complex life cycle has hampered standard methods for the study of pathogenesis. New approaches to elucidate parasite biology using whole genomic methods have provided insight into gene function, transcriptional regulation and stage specific biology [1-4]. Characterization of the in vivo biology of this pathogen, through adaptation of a whole genome approach, would provide insight into the host-parasite relationship, parasite virulence factors and inform new strategies for intervention. Genomic scale transcriptional profiling of P. falciparum during a natural infection is presented. Small amounts of parasite RNA, isolated from a few milliliters of a blood sample are found to be sufficient for whole genome transcriptional analysis. This data show that several genes are differentially expressed in vivo, indicating differences between the transcriptional program of 3D7 laboratory strain parasites growing in culture and naturally occurring infections in the human host.Whole genome expression has been used in s
The Capability Approach and Evaluation of the Well-Being in Senegal: An Operationalization with the Structural Equations Models  [PDF]
Felwine Sarr, Muhammad Ba
Modern Economy (ME) , 2017, DOI: 10.4236/me.2017.81007
Abstract: This article uses the theoretical framework of the capabilities approach to offer a structural assessment model of well-being in the context of Senegal. To this end, we mobilize the Senegalese data (ESPS-II) and an evaluation space including basic and central capabilities of [1] and [2], which are: living conditions, education and health body, non-institutional support and good governance, on the one hand, and the three dimensions of well-being (economic well-being, life satisfaction and subjective well-being), on the other hand. With the modeling technique by structural equations: PLS-PM (Partial Linear Square-Path Modeling), we find that the estimation model of well-being has built good predictive quality. In addition, it shows that the basic capabilities (education, living conditions and health of the body) positively determine well-being (economic well-being, subjective well-being and life satisfaction). Also, economic well-being and life satisfaction positively predict and cause subjective well-being. Contrariwise, non-institutional support and good governance do not significantly cause subjective well-being. Between these two capabilities, only good governance has a significant and positive effect on life satisfaction.
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