Papers by Ibrahima Ndiaye
Journal de Physique de la SOAPHYS
L’augmentation de la quantité de CO2 et le réchauffement climatique due aux énergies fossiles ont... more L’augmentation de la quantité de CO2 et le réchauffement climatique due aux énergies fossiles ont rendu nécessaire le besoin d’explorer d’autres sources d’énergies inépuisables, disponibles et non polluantes telles que les énergies renouvelables. L’énergie hydraulique représente 19% de la production mondiale. Les Petites Centrales hydroélectriques sont de petites unités deproduction peu couteuses. Le potentiel en hydroélectricité dépend du débit et de la hauteur de chute. Dans cette étude, nous sélectionnons des sites en vue de l’évaluation du potentiel en petite hydroélectricité dans le bassin versant de Wassadou sur le fleuve Gambie. Grâce à ArcGis, et au modèle numérique de terrain (MNT) 11 affluents ont été retenus, et 35 sites d’emplacements de petite centrale hydroélectrique (PCH) identifiés. Le modèle hydrologique SWAT a été calibré pour une période d’observation 1990-1995 et validé sur la période 1996-1998. La précision du modèle a été confirmée par le coefficient de détermi...
Feasibility Analysis of Converter-Interfaced Combined Heat and Power System
2020 IEEE Power & Energy Society General Meeting (PESGM)
As a promising new design concept, the converter-interfaced combined heat and power (CHP) system ... more As a promising new design concept, the converter-interfaced combined heat and power (CHP) system is coupled to the bulk grid through a rectifier and a grid-ready tied inverter. Compared to the traditional directly-coupled CHP system, it removes the requirement for oversizing the CHP generator, limits the short-circuit contribution of the generator and simplifies the grid integration process of CHP system. This paper evaluates the economic benefits of this concept by calculating the annualized Return-on-Investment (ROI) and comparing it to the directly-coupled system. The economic analysis includes timeseries simulations to compute energy transactions with the bulk grid as well as sizing the equipment to calculate the capital and operational costs. Obtained results indicate that in majority of user cases evaluated, the converter-interfaced CHP systems can provide better ROI than directly-coupled systems. Given the additional technical benefits provided by inverter-based distributed energy resources (DERs), the proposed concept is proved to be technically viable and economically feasible.
System Level Assessment of the Impact of High Penetration of PV Inverters with Grid Support Capability on Distribution Networks
2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 2019
Power systems simulations using PSCAD have been performed to evaluate the impact to the distribut... more Power systems simulations using PSCAD have been performed to evaluate the impact to the distribution grid of high photovoltaic (PV) penetration. Voltage regulation at load nodes, feeder short-circuit currents and power losses have been analyzed for penetration level up to 60% and compared with a baseline case referring to as no PV. Results show that high PV penetration impacts residential area and non-residential area networks differently. Also, depending on the grid strength, the performance of the network is different. PV micro-inverters, in some cases, can prevent voltage excursion beyond tolerance limits however, they are more effective for power losses reduction. Overall, up to 15% in energy losses can be saved at very high penetration levels. Regarding the short-circuit levels no adjustment in the network infrastructures is required as the PV systems will have inconsequential contribution in feeder short-circuit currents.
We consider metabolic networks with reversible enzymatic reactions. The model is written as a sys... more We consider metabolic networks with reversible enzymatic reactions. The model is written as a system of ordinary differential equations, possibly with inputs and outputs. We prove the global stability of the equilibrium (if it exists), using techniques of monotone systems and compartmental matrices. We show that the equilibrium does not always exist. Finally, we consider a metabolic system coupled with a genetic network, and we study the dependence of the metabolic equilibrium (if it exists) with respect to concentrations of enzymes. We give some conclusions concerning the dynamical behavior of coupled genetic/metabolic systems.
Assurer la continuité des soins au temps de la Covid-19 : défis pour le centre de traitement des addictions à Dakar
La pandemie de COVID-19 a eu un impact sur le fonctionnement des systemes de sante dont les modes... more La pandemie de COVID-19 a eu un impact sur le fonctionnement des systemes de sante dont les modes d'adaptation et de reponse sur le terrain sont encore peu documentes et en cours d'evolution. Le Centre de Prise en charge Integree des Addictions de Dakar (CEPIAD) met en oeuvre depuis 2014 la reduction des risques aupres d'usagers de drogues. La pandemie de COVID-19 et les mesures de sante publique ont ete un obstacle a sa frequentation par les patients, notamment du fait de la limitation des deplacements. Outre la mise en place de mesures preventives et l'application des gestes barrieres dans le centre, le CEPIAD a eu recours a l'emport a domicile de la methadone habituellement dispensee chaque jour dans ses locaux. Le centre a aussi pris en charge des usagers de cannabis incarceres apres leur amnistie. Plusieurs aspects de l'experience du CEPIAD, percue positivement, pourraient etre pertinents hors du contexte pandemique.
Taking Care of Business: Women's Role in Promoting Condom Use in Commercial Encounters
Senegal/AFRICA- P156186- Dakar Bus Rapid Transit Pilot Project - Procurement Plan
L’education musicale academique n’est officialisee au Senegal qu’a partir de 1976, dans l’intenti... more L’education musicale academique n’est officialisee au Senegal qu’a partir de 1976, dans l’intention de democratiser l’acces a la culture a l’ecole. Le but est de former un citoyen senegalais enracine dans sa propre culture et ouvert vers le reste du monde. Mais la concretisation de cette noble ambition a presque echoue en raison d’une « ouverture » qui a pris le pas sur « l’enracinement ». Car la formation des professeurs d’education musicale est calquee sur les contenus de cours legues par les francais et bases essentiellement sur la musique classique europeenne inconnue des senegalais. Ce qui cree une tension par rapport a la culture musicale populaire des eleves. Dans les ecoles, rien n’est prevu pour l’enseignement de cette discipline, au niveau des moyens et materiels didactiques. Les professeurs d’education musicale sont confrontes aussi a un probleme de rapport au savoir academique dans une societe de tradition orale tres islamisee avec un systeme de castes, d’ou des prejuges...
Psychological and social aspects in minors who are victims of sexual abuse
Since its opening in 2006, the Child Psychiatry Department has faced a year on year increasing de... more Since its opening in 2006, the Child Psychiatry Department has faced a year on year increasing demand for the care of child and pre-adolescent victims of sexual abuse. This article is an original work, since very few studies regarding the psychological and social aspects of sexual abuse have been conducted in our country. Based on seven clinical cases, the authors seek to describe the psychosocial realities related to the context of rape among minors and their families seen in relation to rape at the Child Psychiatry Department of CHNPT between July and December of 2012.
Open Journal of Psychiatry, 2022
Context: HIV infection is an infectious, viral, chronic disease described as a public health prob... more Context: HIV infection is an infectious, viral, chronic disease described as a public health problem. It has an impact on bio-psycho-social well-being. Thus, the objective of our study is to decrypt the representations of HIV infection in our patients. Methodology: 31 consecutively recruited HIV-infected patients participated in our study. The completed questionnaire included socio-demographic characteristics, association membership, psycho-social aspects of HIV infection, mode of transmission and adherence to antiretroviral treatment. Secondly, we proceeded to an assessment of the psychological state of the patient. Results: Almost 77% of HIV patients do not date peers in an association. At the time of the study, more than half of patients or 19/31 with HIV had a positive image of the disease. Before the diagnosis of the disease, more than 2/3 of patients with HIV, i.e. 25/31, have a negative image of the
Dengue virus is a major and rapidly growing public health concern in tropic and subtropic regions... more Dengue virus is a major and rapidly growing public health concern in tropic and subtropic regions across the globe. In late 2018, Senegal experienced its largest dengue virus outbreak to date, covering several regions. However, little is known about the genetic diversity of dengue virus (DENV) in Senegal. Here we used molecular tools including metagenomic sequencing to identify 19 previously undetected dengue virus cases from the city of Thiès and assemble 17 complete virus genomes. DENV3 was the most frequent serotype; 11 sequences (65%) were DENV3, 4 sequences were DENV2 and 2 were DENV1. Sequences were closest to recent sequences from West Africa, suggesting ongoing local circulation of viral populations; however, detailed inference is limited by the scarcity of available genomic data. We did not find clear associations with reported clinical signs or symptoms, highlighting the importance of testing for diagnosing febrile diseases. Overall, these findings expand the known range o...
Journal of Water Resources and Ocean Science, 2020
Hydrological modeling of ungauged basins is important and imperative for policymakers and stakeho... more Hydrological modeling of ungauged basins is important and imperative for policymakers and stakeholders in water management. The Kayanga river upstream from the Niandouba dam is subject to extreme pressure caused by natural and anthropogenic factors. The hydro system Niandouba Dam and Confluent Dam are used to providing water for the irrigated perimeters in Anambe. Since there is no data available to evaluate the water resources entering the Niandouba Dam, we used Soil and Water Assessment Tools (SWAT) to set up a hydrological model in the ungauged basin of Kayanga river upstream Niandouba dam. A regionalization approach has been used to predict the river discharge at Niandouba watershed upstream of the Niandouba dam. SWAT model has been calibrated from 01/01/2001 to 31/12/2001 and validated from 01/01/2002 to 31/12/2002, with a daily scale on the Koulountou watershed. During the calibration period, the criteria of goodness of fit are respectively 0.87 for Nash-Sutcliffe Efficiency coefficient (NSE), 0.87 for coefficient of determination (R2), -1.6% for Percent Bias (PBIAS) and 0.36 for Standard Deviation Ratio (RSR). In the validation period, we have found a Nash-Sutcliffe Efficiency coefficient (NSE) of 0.62, a coefficient of determination (R2) of 0.77, a Percent Bias (PBIAS) of +35.9%, Standard Deviation Ratio (RSR) of 0.62. These parameters have been used to generate flows at the entrance of the Niandouba Dam.
Grid Ready, Flexible Large Power Transformer
Modeling CD4+ Cell Count Increase Over a Six-Year Period in HIV-1–Infected Patients on Highly Active Antiretroviral Therapy in Senegal
The American Journal of Tropical Medicine and Hygiene, 2009
To assess the extents and determinants of long-term CD4 cell increases after initiation of antire... more To assess the extents and determinants of long-term CD4 cell increases after initiation of antiretroviral therapy (ART), changes in CD4 cell counts were analyzed in a cohort of HIV-1-infected Senegalese using a mixed-effects model. After a median follow-up of 54 months, an average of 483 CD4 cells/mm3 (95% confidence interval [CI] = 331; 680) was reached. The average asymptote level was approximately 421 cells/mm3 (95% CI = 390; 454) in patients with < 200 cells/mm3 at baseline and approximately 500 cells/mm3 in patients with > 200 cells/mm3. The independent predictors of long-term CD4 cell reconstitution were the baseline CD4 cell count and the monthly average viral load over the entire follow-up. This good long-term immune reconstitution, optimal in subjects with low average viral loads and > 200 CD4 cells/mm3 at baseline, argues in favor of the earliest possible access to ART and underlines the importance of strict compliance with the treatment.
Impact of micro-inverter reactive power support capability in high penetration residential PV networks
2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC), 2015
With the steadily increasing penetration of residential and small commercial photovoltaic (PV) ge... more With the steadily increasing penetration of residential and small commercial photovoltaic (PV) generation, interest has grown in utilizing this renewable generation source to support the power distribution grid, as clusters of residential solar have the potential to be used to provide reactive power support to the grid for voltage and frequency regulation through system level control and communication with the grid operator. Solar electric systems can also be used to improve voltage profiles on distribution feeders and also to provide power factor correction at the meter in each home. In this paper the impact of grid support functions of micro-inverter on the distribution network is studied for high penetration residential PV.
Experimental study and analysis of the stability field for a streamer propagating along an ice surface
Gaodianya Jishu/High Voltage Engineering
ABSTRACT
Processes of Ice Surface Discharges under Lightning Impulse Voltage
The Lancet Respiratory Medicine, 2015
Background HIV-1 infection is associated with increased risk of tuberculosis and a safe and eff e... more Background HIV-1 infection is associated with increased risk of tuberculosis and a safe and eff ective vaccine would assist control measures. We assessed the safety, immunogenicity, and effi cacy of a candidate tuberculosis vaccine, modifi ed vaccinia virus Ankara expressing antigen 85A (MVA85A), in adults infected with HIV-1. We did a randomised, double-blind, placebo-controlled, phase 2 trial of MVA85A in adults infected with HIV-1, at two clinical sites, in Cape Town, South Africa and Dakar, Senegal. Eligible participants were aged 18-50 years, had no evidence of active tuberculosis, and had baseline CD4 counts greater than 350 cells per μL if they had never received antiretroviral therapy or greater than 300 cells per μL (and with undetectable viral load before randomisation) if they were receiving antiretroviral therapy; participants with latent tuberculosis infection were eligible if they had completed at least 5 months of isoniazid preventive therapy, unless they had completed treatment for tuberculosis disease within 3 years before randomisation. Participants were randomly assigned (1:1) in blocks of four by randomly generated sequence to receive two intradermal injections of either MVA85A or placebo. Randomisation was stratifi ed by antiretroviral therapy status and study site. Participants, nurses, investigators, and laboratory staff were masked to group allocation. The second (booster) injection of MVA85A or placebo was given 6-12 months after the fi rst vaccination. The primary study outcome was safety in all vaccinated participants (the safety analysis population). Safety was assessed throughout the trial as defi ned in the protocol. Secondary outcomes were immunogenicity and vaccine effi cacy against Mycobacterium tuberculosis infection and disease, assessed in the per-protocol population. Immunogenicity was assessed in a subset of participants at day 7 and day 28 after the fi rst and second vaccination, and M tuberculosis infection and disease were assessed at the end of the study. The trial is registered with ClinicalTrials.gov, number NCT01151189. Findings Between Aug 4, 2011, and April 24, 2013, 650 participants were enrolled and randomly assigned; 649 were included in the safety analysis (324 in the MVA85A group and 325 in the placebo group) and 645 in the per-protocol analysis (320 and 325). 513 (71%) participants had CD4 counts greater than 300 cells per μL and were receiving antiretroviral therapy; 136 (21%) had CD4 counts above 350 cells per μL and had never received antiretroviral therapy. 277 (43%) had received isoniazid prophylaxis before enrolment. Solicited adverse events were more frequent in participants who received MVA85A (288 [89%]) than in those given placebo (235 [72%]). 34 serious adverse events were reported, 17 (5%) in each group. MVA85A induced a signifi cant increase in antigen 85A-specifi c T-cell response, which peaked 7 days after both vaccinations and was primarily monofunctional. The number of participants with negative QuantiFERON-TB Gold In-Tube fi ndings at baseline who converted to positive by the end of the study was 38 (20%) of 186 in the MVA85A group and 40 (23%) of 173 in the placebo group, for a vaccine effi cacy of 11•7% (95% CI -41•3 to 44•9). In the per-protocol population, six (2%) cases of tuberculosis disease occurred in the MVA85A group and nine (3%) occurred in the placebo group, for a vaccine effi cacy of 32•8% (95% CI -111•5 to 80•3). Interpretation MVA85A was well tolerated and immunogenic in adults infected with HIV-1. However, we detected no effi cacy against M tuberculosis infection or disease, although the study was underpowered to detect an eff ect against disease. Potential reasons for the absence of detectable effi cacy in this trial include insuffi cient induction of a vaccineinduced immune response or the wrong type of vaccine-induced immune response, or both.
2009 International Multiconference on Computer Science and Information Technology, 2009
Africa is the fastest growing mobile phone market in the world. The portfolio of available mobile... more Africa is the fastest growing mobile phone market in the world. The portfolio of available mobile phone applications that impact the populations of the continent is however limited in number and scope. Future African graduates will be the main vectors for the development of mobile applications. In this paper we present a model of teaching mobile application development for social changes emphasizing software engineering practices. The innovation is that students develop and deploy applications for people of their local communities. This model has been used successfully in Senegal. Applications for craft workers and young children have been developed. Findings, lessons learned and guidelines for instructors interested in similar initiatives are presented. Developing mobile applications is a challenging endeavor where technological and software engineering knowledge and creativity are crucial. Mobile applications are deployed on devices that all come with different specifications (e.g., size, memory, input systems, mobile connectivity options, and APIs). The difficulties are increased considering that fact that one standard replaces the next in the industry. These restrictions and constraints require developers to be imaginative and have deep knowledge in hardware and telecommunications on top of software development processes, design, programming, user interaction design, and quality assurance. Java ME is the leading programming language for development of mobile phones with 80% of Java-enabled phones. Applications can also be developed in Java FX, Python, C, C++, Objective C, Flash Lite, and JavaScript, HTML and CSS. Development environments for Java ME include the Sun Wireless Took Kit, NetBeans, and the EclipeME plugin within Eclipse. User interaction determines considerably the adoption of rejection of mobile applications. Based on the difficulties of creating similar and engaging user experience on various devices, user interface libraries have been created. Frameworks such as LWUIT (LightWeight UI Toolkit) () and KUIX (Kalmeo User Inter face eXtensions) () augment the standard low-level and high-level user interfaces APIs of Java ME. In this paper , we describe a model of teaching mobile application development for social changes that is influ-383
Chemical composition of essential oils and hydrosol extracts of daucus muricatus and assessment of its antioxidant activity
A comparative study of volatile compounds from Daucus muricatus obtained by hydrodistillation and... more A comparative study of volatile compounds from Daucus muricatus obtained by hydrodistillation and liquid–liquid extraction by GC and gas chromatography mass spectroscopy (GCMS) was conducted. The essential oils extracted from roots were mainly composed of aliphatic compounds while oils extracted from aerial part were characterized by monoterpene hydrocarbons. However, the GCMS analyses of composition hydrosol extracts shows only oxygenated compounds; no hydrocarbons were noted. The antioxidant activity of the hydrosol extracts exhibited the high antioxidant activity with IC50 value of 50.08 and 63.05 μg.mL−1 for roots and aerial parts, respectively, better than from synthetic antioxidant BHT (103.98 μg.mL−1).
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Papers by Ibrahima Ndiaye