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Contribution of Satellite Observations in the Optical and Microphysical Characterization of Aerosols in Burkina Faso, West Africa

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Atmospheric and Climate Sciences 2024年第1期14卷 154-171页

作者： Nébon Bado serge Dimitri Bazyomo Germain Wende Pouiré Ouedraogo bruno Korgo Mamadou Simina Dramé Florent P. Kieno Sié Kam Laboratoire d’Energies Thermiques Renouvelables (L.E.T.RE) Université Joseph KI ZERBO Ouaga Burkina Faso Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon-Fongang Université Cheikh Anta DIOP Dakar-Fann Sénégal Institute of Mathematics and Physical Sciences University of Abomey-Calavi Porto-Novo Benin

In this work, we proceed to an optical and microphysical analysis of the observations reversed by the MODIS, SeaWiFS, MISR and OMI sensors with the aim of proposing the best-adapted airborne sensor for better monitoring of aerosols in Burkina Faso. To this end, a comparison of AOD between satellite observations and in situ measurements at the Ouagadougou site reveals an underestimation of AERONET AOD except for OMI which overestimates them. Also, an inter-comparison done based on the linear regression line representation shows the correlation between the aerosol models incorporated in the airborne sensor inversion algorithms and the aerosol population probed. This can be seen through the correlation coefficients R which are 0.84, 0.64, 0.55 and 0.054 for MODIS, SeaWiFS, MISR and OMI respectively. Furthermore, an optical analysis of aerosols in Burkina Faso by the MODIS sensor from 2001 to 2016 indicates a large spatial and temporal variability of particles strongly dominated by desert dust. This is corroborated by the annual and seasonal cycles of the AOD at 550 nm and the Angström coefficient measured in the spectral range between 412 nm and 470 nm. A zoom on a few sites chosen according to the three climatic zones confirms the majority presence of mineral aerosols in Burkina Faso, whose maxima are observed in spring and summer.

关键词： AERONET Airborne Sensors Aerosol Optical and Microphysical Properties

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Investigation of bright and dark solitons in α,β-Fermi Pasta Ulam lattice

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Chinese Physics B 2021年第2期30卷 211-219页

作者： Nkeh Oma Nfor serge bruno ya.goué Francois Marie Moukam Kakmeni Department of Physics Higher Teacher Training College BambiliThe University of BamendaP.O.Box 39Bambili-Cameroon Complex Systems and Theoretical Biology Group Laboratory of Research on Advanced Materials and Nonlinear Science(LaRAMaNS)Department of PhysicsFaculty of ScienceUniversity of BueaP.O.Box 63 Buea-Cameroon

We consider the Hamiltonian ofα,β-Fermi Pasta Ulam lattice and explore the Hamilton-Jacobi formalism to obtain the discrete equation of *** using the continuum limit approximations and incorporating some normalized parameters,the extended Korteweg-de Vries equation is obtained,with solutions that elucidate on the Fermi Pasta Ulam *** further derive the nonlinear Schrodinger amplitude equation from the extended Korteweg-de Vries equation,by exploring the reductive perturbative *** dispersion and nonlinear coefficients of this amplitude equation are functions of theαandβparameters,with theβparameter playing a crucial role in the modulational instability analysis of the ***βgreater than or equal to zero,no modulational instability is observed and only dark solitons are identified in the *** forβless than zero,bright solitons are traced in the lattice for some large values of the *** of numerical simulations of both the Korteweg-de Vries and nonlinear Schr¨odinger amplitude equations with periodic boundary conditions clearly show that the bright solitons conserve their amplitude and shape after collisions.

关键词： Fermi Pasta Ulam paradox bright dark

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Exact transverse solitary and periodic wave solutions in a coupled nonlinear inductor-capacitor network

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Chinese Physics B 2018年第9期27卷 434-443页

作者： serge bruno ya.goué Guy Roger Deffo Eric Tala-Tebue Francois Beceau Pelap Department of Physics Higher Teacher Training College Bambili the University of Bamenda Unité de Recherche de Mécanique et de Modélisation des Systèmes Physiques (UR-2MSP) Faculté des Sciences Université de Dschang Department of Telecommunication and Network Engineering Fotso Victor University Institute of Technology The University of Dschang P.O. Box 134 Bandjoun Cameroon

Through two methods, we investigate the solitary and periodic wave solutions of the differential equation describing a nonlinear coupled two-dimensional discrete electrical lattice. The fixed points of our model equation are examined and the bifurcations of phase portraits of this equation for various values of the front wave velocity are presented. Using the sineGordon expansion method and classic integration, we obtain exact transverse solutions including breathers, bright solitons,and periodic solutions.

关键词： nonlinear electrical lattices two-dimensional network sine-Gordon expansion exact transverse solitary wave solutions

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Flow fields and particle trajectories beneath a tidal bore:A numerical study

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International Journal of Sediment Research 2018年第3期33卷 351-370页

作者： Adrien Berchet bruno Simon Anthony Beaudoin Pierre Lubin Germain Rousseaux serge Huberson Institut Pprime Université de Bordeaux

Tidal bores may appear in some estuaries when the tides quickly reach a high level. This phenomenon is rare but has a strong impact during its short duration: i.e. the river bed is significantly eroded and sediments are then transported. In this paper, the trajectories of suspended particles induced by this flow are numerically studied. Four undular bores with Froude numbers between 1.1 and 1.2 are *** similar Froude numbers, various initial flow conditions were selected to produce or not an inversion of the flow direction during the bore passage. The particle trajectories associated with each distinct flow configuration are presented and analyzed. These trajectories, estimated by solving the Maxey-Riley equation, appear to be very different even though the Froude numbers of flows are *** observations are important because the Froude number is often used to characterize a tidal bore as it describes well the free surface, however, it cannot describe the sediment transport. Finally, Chen’s model of wave-current interactions is adapted to fit the cases studied and is applied to the four bores simulated. The results highlight that this latter model can reproduce the observed trajectories and dissociate their different components. From this model, it is shown that the inertial and Basset history effects can be neglected compared to the gravity and flow entrainment effects due to the viscous drag when one wants to determine the long-term trajectories of suspended particles.

关键词： Tidal bores Sediment transport Trajectories Physical modeling Numerical modeling

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Generalization of the Global Error Minimization for Constructing Analytical Solutions to Nonlinear Evolution Equations

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Journal of Applied Mathematics and Physics 2015年第9期3卷 1151-1158页

作者： serge bruno ya.goué Bonaventure Nana Department of Physics Higher Teacher Training College-Bambili The University of Bamenda Bamenda Cameroon

The global error minimization is a variational method for obtaining approximate analytical solutions to nonlinear oscillator equations which works as follows. Given an ordinary differential equation, a trial solution containing unknowns is selected. The method then converts the problem to an equivalent minimization problem by averaging the squared residual of the differential equation for the selected trial solution. Clearly, the method fails if the integral which defines the average is undefined or infinite for the selected trial. This is precisely the case for such non-periodic solutions as heteroclinic (front or kink) and some homoclinic (dark-solitons) solutions. Based on the fact that these types of solutions have vanishing velocity at infinity, we propose to remedy to this shortcoming of the method by averaging the product of the residual and the derivative of the trial solution. In this way, the method can apply for the approximation of all relevant type of solutions of nonlinear evolution equations. The approach is simple, straightforward and accurate as its original formulation. Its effectiveness is demonstrated using a Helmholtz-Duffing oscillator.

关键词： Global Error Minimization Heteroclinic Solution Homoclinic Solution Front/Kink Dark/Anti-Dark Soliton

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Exact solitary wave solutions of a nonlinear Schrdinger equation model with saturable-like nonlinearities governing modulated waves in a discrete electrical lattice

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Chinese Physics B 2018年第12期27卷 420-430页

作者： serge bruno ya.goue Guy Roger Deffo Eric Tala-Tebue Francois Beceau Pelap Department of Physics Higher Teacher Training College BambiliThe University ofBamendaP.O.Box 39Bamenda Cameroon Unite de Recherche de Mecanique et de Modelisation des Systemes Physiques (UR-2MSP) Faculte des SciencesUniversite de DschangBP 69DschangCameroun Department of Telecommunication and Network Engineering Fotso Victor University Institute of TechnologyThe University of DschangP.O.Box 134BandjounCameroon

In this paper, we introduce and propose exact and explicit analytical solutions to a novel model of the nonlinear Schr¨odinger(NLS) equation. This model is derived as the equation governing the dynamics of modulated cutoff waves in a discrete nonlinear electrical lattice. It is characterized by the addition of two terms that involve time derivatives to the classical equation. Through those terms, our model is also tantamount to a generalized NLS equation with saturable;which suggests that the discrete electrical transmission lines can potentially be used to experimentally investigate wave propagation in media that are modeled by such type of nonlinearity. We demonstrate that the new terms can enlarge considerably the forms of the solutions as compared to similar NLS-type equations. Sine–Gordon expansion-method is used to derive numerous kink, antikink, dark, and bright soliton solutions.

关键词： nonlinear Schrdinger equation nonlinear time derivative terms saturable nonlinearity exact solitary solutions

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Dissipation and amplification management in an electrical model of microtubules: Hybrid behavior network

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Chinese Physics B 2023年第11期32卷 392-400页

作者： Sedric Ndoungalah Guy Roger Deffo Arnaud Djine serge bruno ya.goue Department of Physics Faculty of ScienceUniversity of BamendaP.O.Box 39 BamendaCameroon Research Unit of Automation and Applied Computers(UR-AIA) Department of Electrical EngineeringIUT-FV of BandjounUniversity of DschangBP 134BandjounCameroon Department of Physics Higher Teacher Training College BambiliThe University of BamendaP.O.Box 39 BamendaCameroon

The control of dissipation and amplification of solitary waves in an electrical model of a microtubule is *** model consists of a shunt nonlinear resistance–capacitance(J(V)–C(V)) circuit and a series resistance–inductance(R–L) circuit. Through linear dispersion analysis, two features of the network are found, that is, low bandpass and bandpass filter characteristics. The effects of the conductance’s parameter λ on the linear dispersion curve are also analyzed. It appears that an increase of λ induces a decrease(an increase) of the width of the bandpass filter for positive(negative) values of λ. By applying the reductive perturbation method, we derive the equation governing the dynamics of the modulated waves in the system. This equation is the well-known nonlinear Schr?dinger equation extended by a linear term proportional to a hybrid parameter σ, i.e., a dissipation or amplification coefficient. Based on this parameter, we successfully demonstrate the hybrid behavior(dissipation and amplification) of the system. The exact and approximate solitary wave solutions of the obtained equation are derived, and the effects of the coefficient σ on the characteristic parameters of these waves are investigated. Using the analytical solutions found, we show numerically that the waves that are propagated throughout the system can be dissipated, amplified, or remain stable depending on the network parameters. These results are not only in agreement with the analytical predictions, but also with the existing experimental results in the literature.

关键词： microtubule dissipation and amplification hybrid behavior solitary wave solutions

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Improvement of Harmonic Balance Using Jacobian Elliptic Functions

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Journal of Applied Mathematics and Physics 2015年第6期3卷 680-690页

作者： serge bruno ya.goué Bonaventure Nana Olivier Tiokeng Lekeufack Department of Physics Higher Teacher Training College-Bambili The University of Bamenda Bamenda Cameroon Laboratory of Mechanics Department of Physics Faculty of Science The University of Yaoundé 1 Yaoundé Cameroon

We propose a method for finding approximate analytic solutions to autonomous single degree-of-freedom nonlinear oscillator equations. It consists of the harmonic balance with linearization in which Jacobian elliptic functions are used instead of circular trigonometric functions. We show that a simple change of independent variable followed by a careful choice of the form of anharmonic solution enable to obtain highly accurate approximate solutions. In particular our examples show that the proposed method is as easy to use as existing harmonic balance based methods and yet provides substantially greater accuracy.

关键词： Harmonic Balance Linearization Continuous Force Function Single Degree-of-Freedom Conservative System Jacobian Elliptic Functions Symmetric Oscillations

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Signature of chaos in the semi quantum behavior of a classically regular triple well heterostructure

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Natural Science 2010年第3期2卷 145-154页

作者： Tiokeng Olivier Lekeufack serge bruno ya.goue Timoleon Crepin Kofane 不详

We analyze the phenomenon of semiquantum chaos in the classically regular triple well model from classical to quantum. His dynamics is very rich because it provides areas of regular be-havior, chaotic ones and multiple quantum tun-neling depending on the energy of the system as the Planck’s constant varies from 0 to 1. The Time Dependent Variational Principle TDVP using generalized Gaussian trial wave function, which, in many-body theory leads to the Hartree Fock Approximation TDHF, is added to the tech-niques of Gaussian effective potentials and both are used to study the system. The extended classical system with fluctuation variables non- linearly coupled to the average variables exhibit energy dependent transitions between regular behavior and semi quantum chaos monitored by bifurcation diagram together with some numerical indicators.

关键词： Nonlinear Dynamics Semi Quantum Chaos Effective Potential

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Implementing uterine balloon tamponade(UBT)device for immediate postpartum hemorrhage management:Leveraging resource allocation and highlighting noteworthy experiences

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Gynecology and Obstetrics Clinical Medicine 2023年第3期3卷 175-180页

作者： Mian Dehi Boston Guie Privat Apollinaire Horo Aka Edele Kouakou Konan Virginie Aholoupke bruno KonéSeydou Rochon Sarah Boni serge Burke Thomas F Felix Houphouet Boigny University Cote d’Ivoire Division of Global Health and Human Rights Department of Emergency MedicineCote d’Ivoire National Mother and Child Health Program Côte d'Ivoire Cote d’Ivoire Massachusetts General Hospital Division of Global Health and Human Rights BostonMAUSA Harvard T.H.Chan School of Public Health BostonMAUSA Harvard Medical School BostonMAUSA

Background The use of uterine balloon tamponade(UBT)devices for intrauterine packing and management of vaginal bleeding by uterine atony has shown promising results in improving the quality of care and reducing maternal *** This report aims to provide an overview of progress made in implementing UBT devices in northern Cote d'*** and methods A four-year retrospective study was conducted in the North-East(163,645),North-Center(351,909),and North-West(57,983).In 2017,UBT was adopted by members of the healthcare ***,5 national and 32 regional trainers have been *** training session was a theoretical and practical program with a low *** is a male condom tied to a urinary catheter,filled with *** outcomes included stopping bleeding,avoiding the need for surgery,and preventing maternal deaths(MD).In 2018,3,515 UBT devices were *** 2019,monitoring tools and transmission circuits of the data were *** 2020,the collection of data and local manufacturing was *** During the process,978 health workers,mainly midwife(52.0%)and nurses(32.2%)out of the 1,295 assigned were *** number of trained individuals decreased from 209 in 2019 to 160 in 2020.A total of 1,715 UBT devices were locally manufactured,adding to the existing gift of 5,080 devices,with total availability of 6,*** distribution of devices increased from 2017 to 2019 but decreased in *** rates increased from 87.3%in 2017(365/418)to 95.0%in 2019(556/585)and slightly decreased in 2020 to 98.0%(681/695).Adverse outcomes(144/2,193),included MD(35/2,193)and medical evacuation to the surgical center(109/2,193).Conclusion The implementation of UBT in northern Cote d'Ivoire successfully reduced maternal death rates caused by immediate post-partum hemorrhage(IPPH).However,to ensure sustainability,further improvements are needed,including increased monitoring,ongoing training,and device availability.

关键词： Implementation Uterine balloon tamponade Post-partum hemorrhage Health providers Health regions

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