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Papers by Aissatou Thioro Dia Ndiaye

Research paper thumbnail of Projected Changes in Solar PV and Wind Energy Potential over West Africa: An Analysis of CORDEX-CORE Simulations

Energies

Renewable energy development is growing fast and is expected to expand in the next decades in Wes... more Renewable energy development is growing fast and is expected to expand in the next decades in West Africa as a contribution to addressing the power demand and climate change mitigation. However, the future impacts of climate change on solar PV and the wind energy potential in the region are still unclear. This study investigates the expected future impacts of climate change on solar PV and wind energy potential over West Africa using an ensemble of three regional climate models (RCMs). Each RCM is driven by three global climate models (GCMs) from the new coordinated high-resolution output for regional evaluations (CORDEX-CORE) under the RCP8.5 scenario. Two projection periods were used: the near future (2021–2050) and the far future (2071–2100). For the model evaluation, reanalysis data from ERA5 and satellite-based climate data (SARAH-2) were used. The models and their ensemble mean (hereafter Mean) show acceptable performance for the simulations of the solar PV potential, the wind...

Research paper thumbnail of Wentzel-Laplace eigenvalues comparison

Cornell University - arXiv, Jun 21, 2020

In this paper we present quantitative comparisons between the Wentzel-Laplace eigenvalues, Steklo... more In this paper we present quantitative comparisons between the Wentzel-Laplace eigenvalues, Steklov eigenvalues and Laplacian eigenvalues on the boundary of the target manifold using Riccati comparison techniques to estimate the Hessian of the distance function from the boundary. Contents 12 3.3. Sectionnal curvature comparison 15 4. Estimates based on Ricci curvature with Reilly identity 24 References 27

Research paper thumbnail of Isoperimetric bounds for Wentzel-Laplace eigenvalues on Riemannian manifolds

Cornell University - arXiv, May 24, 2020

In this paper, we investigate eigenvalues of the Wentzel-Lapla ce operator on a bounded domain in... more In this paper, we investigate eigenvalues of the Wentzel-Lapla ce operator on a bounded domain in some Riemannian manifold. We prove asymptotically optimal estimates, according to the Weyl's law through bounds that are given in terms of the isoperimetric ratio of the domain. Our results show that the isoperimetric ratio allows to control the entire spectrum of the Wentzel-Laplace operator in various ambient spaces. 1 + c n Vol(Ω)∆B Vol(B) 2 , c n := Vol(Ω) n−1 n. In the numerator Vol stands for the (n − 1)-Riemannian volume and for the n-Riemannian volume from g in the denominator. Our first result provides an upper bound in the case of Euclidean domains. We respectively denote ω n and ρ n−1 = nω n the volumes of the unit ball and the unit sphere in the n-dimensional Euclidean space. Theorem 1.1. Let n 3 and Ω ⊂ IR n be a bounded euclidean domain with smooth boundary Γ. Then, for every k 1, one has λ β W,k (Ω) ζ 1 (n) Vol(Ω) Vol(Γ) 1− 2 n k Vol(Γ) 2 n + ζ 2 (n)I(Ω) 1+ 2 n−1

Research paper thumbnail of Asymptotically sharp bound for Wentzel-Laplace eigenvalues

arXiv: Metric Geometry, 2020

We prove asymptotically optimal upper bounds for the eigenvalues of the Wentzel-Laplace operator ... more We prove asymptotically optimal upper bounds for the eigenvalues of the Wentzel-Laplace operator on Riemannian manifolds with Ricci curvature bounded below. These bounds depend highly on the geometry of the boundary in addition to the dimension and the volume of the manifold.

Research paper thumbnail of About Bounds for Eigenvalues of the Laplacian with Density

Symmetry, Integrability and Geometry: Methods and Applications, 2020

Let M denote a compact, connected Riemannian manifold of dimension n ∈ N. We assume that M has a ... more Let M denote a compact, connected Riemannian manifold of dimension n ∈ N. We assume that M has a smooth and connected boundary. Denote by g and dv g respectively, the Riemannian metric on M and the associated volume element. Let ∆ be the Laplace operator on M equipped with the weighted volume form dm := e −h dv g. We are interested in the operator L h • := e −h(α−1) (∆ • +αg(∇h, ∇•)), where α > 1 and h ∈ C 2 (M) are given. The main result in this paper states about the existence of upper bounds for the eigenvalues of the weighted Laplacian L h with the Neumann boundary condition if the boundary is non-empty.

Research paper thumbnail of Impact of a red clover winter cover crop on carbon and nitrogen mineralization by microorganisms in soil aggregates

Research paper thumbnail of Trend in Antibiotic Resistance of Streptococcus Pneumoniae and Haemophilus Influenzae Strains Isolated from Community Acquired Respiratory Tract Infections in Dakar, Senegal Between 2005 and 2008

Microbiology Insights, 2010

Development of antibiotic resistance among common respiratory pathogens is a major cause of conce... more Development of antibiotic resistance among common respiratory pathogens is a major cause of concern worldwide. Streptococcus pneumoniae and Haemophilus influenzae are among the most common respiratory pathogens. In this study, representative samples obtained from 3 different medical centers in Dakar, Senegal were subjected to antibiotic susceptibility testing. The samples were collected from 2005 to 2008 and the data obtained was compared to establish resistance patterns between the two years (i.e. 2005–2006 to 2007–2008). S. pneumoniae exhibited a significant increase in the resistance to azithromycin and the intermediate susceptibility to penicillin G and cotrimoxazole. H. influenzae also exhibited a significant increase in resistance to azithromycin and intermediate susceptibility to chloramphenicol. None of H. influenzae samples were resistant to amoxicillin/clavulanic acid, cephalosporin and fluroquinolones and most of the S. pneumoniae isolates demonstrated high susceptibility...

Research paper thumbnail of The Absence of Anti‐Tat Antibodies Is Associated with Risk of Disease Progression in HIV‐2 Infection

The Journal of Infectious Diseases, 2006

The Tat protein of human immunodeficiency virus (HIV) is essential for viral replication and has ... more The Tat protein of human immunodeficiency virus (HIV) is essential for viral replication and has extracellular pathogenic activity. We sought to determine whether the anti-Tat antibody response was predictive of disease progression in 144 HIV type 2 (HIV-2)-infected subjects observed longitudinally between 1985 and 2003. Sixty-eight percent of the subjects tested positive for anti-Tat antibodies, with reactivity notably established early after seroconversion and stably maintained over the course of infection. The risk and rate of progression to advanced HIV-2 AIDS was significantly higher in anti-Tat-negative subjects than in anti-Tat-positive subjects, extending the importance of this prognostic marker for HIV-2 AIDS.

Research paper thumbnail of Projected Changes in Solar PV and Wind Energy Potential over West Africa: An Analysis of CORDEX-CORE Simulations

Energies

Renewable energy development is growing fast and is expected to expand in the next decades in Wes... more Renewable energy development is growing fast and is expected to expand in the next decades in West Africa as a contribution to addressing the power demand and climate change mitigation. However, the future impacts of climate change on solar PV and the wind energy potential in the region are still unclear. This study investigates the expected future impacts of climate change on solar PV and wind energy potential over West Africa using an ensemble of three regional climate models (RCMs). Each RCM is driven by three global climate models (GCMs) from the new coordinated high-resolution output for regional evaluations (CORDEX-CORE) under the RCP8.5 scenario. Two projection periods were used: the near future (2021–2050) and the far future (2071–2100). For the model evaluation, reanalysis data from ERA5 and satellite-based climate data (SARAH-2) were used. The models and their ensemble mean (hereafter Mean) show acceptable performance for the simulations of the solar PV potential, the wind...

Research paper thumbnail of Wentzel-Laplace eigenvalues comparison

Cornell University - arXiv, Jun 21, 2020

In this paper we present quantitative comparisons between the Wentzel-Laplace eigenvalues, Steklo... more In this paper we present quantitative comparisons between the Wentzel-Laplace eigenvalues, Steklov eigenvalues and Laplacian eigenvalues on the boundary of the target manifold using Riccati comparison techniques to estimate the Hessian of the distance function from the boundary. Contents 12 3.3. Sectionnal curvature comparison 15 4. Estimates based on Ricci curvature with Reilly identity 24 References 27

Research paper thumbnail of Isoperimetric bounds for Wentzel-Laplace eigenvalues on Riemannian manifolds

Cornell University - arXiv, May 24, 2020

In this paper, we investigate eigenvalues of the Wentzel-Lapla ce operator on a bounded domain in... more In this paper, we investigate eigenvalues of the Wentzel-Lapla ce operator on a bounded domain in some Riemannian manifold. We prove asymptotically optimal estimates, according to the Weyl's law through bounds that are given in terms of the isoperimetric ratio of the domain. Our results show that the isoperimetric ratio allows to control the entire spectrum of the Wentzel-Laplace operator in various ambient spaces. 1 + c n Vol(Ω)∆B Vol(B) 2 , c n := Vol(Ω) n−1 n. In the numerator Vol stands for the (n − 1)-Riemannian volume and for the n-Riemannian volume from g in the denominator. Our first result provides an upper bound in the case of Euclidean domains. We respectively denote ω n and ρ n−1 = nω n the volumes of the unit ball and the unit sphere in the n-dimensional Euclidean space. Theorem 1.1. Let n 3 and Ω ⊂ IR n be a bounded euclidean domain with smooth boundary Γ. Then, for every k 1, one has λ β W,k (Ω) ζ 1 (n) Vol(Ω) Vol(Γ) 1− 2 n k Vol(Γ) 2 n + ζ 2 (n)I(Ω) 1+ 2 n−1

Research paper thumbnail of Asymptotically sharp bound for Wentzel-Laplace eigenvalues

arXiv: Metric Geometry, 2020

We prove asymptotically optimal upper bounds for the eigenvalues of the Wentzel-Laplace operator ... more We prove asymptotically optimal upper bounds for the eigenvalues of the Wentzel-Laplace operator on Riemannian manifolds with Ricci curvature bounded below. These bounds depend highly on the geometry of the boundary in addition to the dimension and the volume of the manifold.

Research paper thumbnail of About Bounds for Eigenvalues of the Laplacian with Density

Symmetry, Integrability and Geometry: Methods and Applications, 2020

Let M denote a compact, connected Riemannian manifold of dimension n ∈ N. We assume that M has a ... more Let M denote a compact, connected Riemannian manifold of dimension n ∈ N. We assume that M has a smooth and connected boundary. Denote by g and dv g respectively, the Riemannian metric on M and the associated volume element. Let ∆ be the Laplace operator on M equipped with the weighted volume form dm := e −h dv g. We are interested in the operator L h • := e −h(α−1) (∆ • +αg(∇h, ∇•)), where α > 1 and h ∈ C 2 (M) are given. The main result in this paper states about the existence of upper bounds for the eigenvalues of the weighted Laplacian L h with the Neumann boundary condition if the boundary is non-empty.

Research paper thumbnail of Impact of a red clover winter cover crop on carbon and nitrogen mineralization by microorganisms in soil aggregates

Research paper thumbnail of Trend in Antibiotic Resistance of Streptococcus Pneumoniae and Haemophilus Influenzae Strains Isolated from Community Acquired Respiratory Tract Infections in Dakar, Senegal Between 2005 and 2008

Microbiology Insights, 2010

Development of antibiotic resistance among common respiratory pathogens is a major cause of conce... more Development of antibiotic resistance among common respiratory pathogens is a major cause of concern worldwide. Streptococcus pneumoniae and Haemophilus influenzae are among the most common respiratory pathogens. In this study, representative samples obtained from 3 different medical centers in Dakar, Senegal were subjected to antibiotic susceptibility testing. The samples were collected from 2005 to 2008 and the data obtained was compared to establish resistance patterns between the two years (i.e. 2005–2006 to 2007–2008). S. pneumoniae exhibited a significant increase in the resistance to azithromycin and the intermediate susceptibility to penicillin G and cotrimoxazole. H. influenzae also exhibited a significant increase in resistance to azithromycin and intermediate susceptibility to chloramphenicol. None of H. influenzae samples were resistant to amoxicillin/clavulanic acid, cephalosporin and fluroquinolones and most of the S. pneumoniae isolates demonstrated high susceptibility...

Research paper thumbnail of The Absence of Anti‐Tat Antibodies Is Associated with Risk of Disease Progression in HIV‐2 Infection

The Journal of Infectious Diseases, 2006

The Tat protein of human immunodeficiency virus (HIV) is essential for viral replication and has ... more The Tat protein of human immunodeficiency virus (HIV) is essential for viral replication and has extracellular pathogenic activity. We sought to determine whether the anti-Tat antibody response was predictive of disease progression in 144 HIV type 2 (HIV-2)-infected subjects observed longitudinally between 1985 and 2003. Sixty-eight percent of the subjects tested positive for anti-Tat antibodies, with reactivity notably established early after seroconversion and stably maintained over the course of infection. The risk and rate of progression to advanced HIV-2 AIDS was significantly higher in anti-Tat-negative subjects than in anti-Tat-positive subjects, extending the importance of this prognostic marker for HIV-2 AIDS.