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Estimated Bounds for Zeros of Polynomials from Traces of Graeffe Matrices

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Advances in Linear Algebra & Matrix Theory 2014年第4期4卷 210-215页

作者： ousmane moussa tessa Maimouna Salou Morou Amidou Département de Mathématiques et d’informatique Université A. Moumouni de Niamey Niamey Niger Institut de Recherche sur l’Enseignement des Mathématiques Université A. Moumouni de Niamey Niamey Niger

In this paper, we combine Graeffe matrices with the classical numerical method of Dandelin-Graeffe to estimate bounds for the moduli of the zeros of polynomials. Furthermore, we give some examples showing significant ... 详细信息

关键词： Graeffe Matrices Numerical Approximation of Eigenvalues Dandelin-Graeffe’s Method Bounds of Zeros of Polynomial

Bounds for Polynomial’s Roots from Hessenberg Matrices and Gershgorin’s Disks

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Advances in Pure Mathematics 2021年第12期11卷 963-977页

作者： Mamoudou Amadou Bondabou ousmane moussa tessa Maimouna Salou Département de Mathématiques et d’informatique Université A. Moumouni Niamey Niger

The goal of this study is to propose a method of estimation of bounds for roots of polynomials with complex coefficients. A well-known and easy tool to obtain such information is to use the standard Gershgorin’s theorem, however, it doesn’t take into account the structure of the matrix. The modified disks of Gershgorin give the opportunity through some geometrical figures called Ovals of Cassini, to consider the form of the matrix in order to determine appropriated bounds for roots. Furthermore, we have seen that, the Hessenbeg matrices are indicated to estimate good bounds for roots of polynomials as far as we become improved bounds for high values of polynomial’s coefficients. But the bounds are better for small values. The aim of the work was to take advantages of this, after introducing the Dehmer’s bound, to find an appropriated property of the Hessenberg form. To illustrate our results, illustrative examples are given to compare the obtained bounds to those obtained through classical methods like Cauchy’s bounds, Montel’s bounds and Carmichel-Mason’s bounds.

关键词： Bounds for Roots of Polynomials Gershgorin Frobenius Companion Matrix Hessenberg Matrices Ovals of Cassini

Bounds for Polynomial’s Roots from Fiedler and Sparse Companion Matrices for Submultiplicative Matrix Norms

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Advances in Linear Algebra & Matrix Theory 2021年第1期11卷 1-13页

作者： Mamoudou Amadou Bondabou ousmane moussa tessa Amidou Morou Département de Mathématiques et d’Informatique Université Abdou Moumouni Niamey Niger Institut de Recherche sur l’Enseignement des Mathématiques Université A. Moumouni de Niamey Niamey Niger

We use submultiplicative companion matrix norms to provide new bounds for roots for a given polynomial P(X) over the field C[X]. From a n×n Fiedler companion matrix C, sparse companion matrices and triangular Hessenberg matrices are introduced. Then, we identify a special triangular Hessenberg matrix Lr, supposed to provide a good estimation of the roots. By application of Gershgorin’s theorems to this special matrix in case of submultiplicative matrix norms, some estimations of bounds for roots are made. The obtained bounds have been compared to known ones from the literature precisely Cauchy’s bounds, Montel’s bounds and Carmichel-Mason’s bounds. According to the starting formel of Lr, we see that the more we have coefficients closed to zero with a norm less than 1, the more the Sparse method is useful.

关键词： Fiedler Matrices Polynomial’s Roots Bounds for Polynomials Companion Matrices Sparse Companion Matrices Hessenberg Matrices Submultiplicative Matrix Norm

A Stochastic SVIR Model for Measles

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Bounds for Polynomial’s Roots from Fiedler and Sparse Companion Matrices for Submultiplicative Matrix Norms

Applied Mathematics（应用数学） 2021年第3期

作者： moussa Seydou ousmane moussa tessa

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Bounds for Polynomial’s Roots from Hessenberg Matrices and Gershgorin’s Disks

Advances in Linear Algebra & Matrix Theory（线性代数与矩阵理论研究进展） 2021年第1期

作者： Mamoudou Amadou Bondabou ousmane moussa tessa Amidou Morou

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Scalable Jet-Based Fabrication of PEI-Hydrogel Particles for CO_(2)Capture

Advances in Pure Mathematics（理论数学进展） 2021年第12期

作者： Mamoudou Amadou Bondabou ousmane moussa tessa Maimouna Salou

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Energy & Environmental Materials 2024年第6期7卷 351-358页

作者： Jieke Jiang Eline van Daatselaar Hylke Wijnja tessa de Koning Gans Michel Schellevis Cornelis H.Venner Derk W.F.Brilman Claas Willem Visser Engineering Fluid Dynamics Group Department of Thermal and Fluid EngineeringFaculty of Engineering TechnologyUniversity of Twente7500AEEnschedeThe Netherlands Sustainable Process Technology Faculty of Science and TechnologyUniversity of Twente7500AEEnschedeThe Netherlands

The capture,regeneration,and conversion of CO_(2)from ambient air and flue gas streams are critical aspects of mitigating global *** sorbents for CO_(2)absorption are very promising as they have high mass transfer areas without energy input and reduce emissions and minimize corrosion as compared to liquid ***,precisely tunable solid CO_(2)sorbents are difficult to ***,we demonstrate the high-throughput production of hydrogel-based CO_(2)-absorbing particles via liquid *** wrapping a liquid jet consisting of an aqueous solution of cross-linkable branched polyethylenimine(PEI)with a layer of suspension containing hydrophobic silica nanoparticles,monodisperse droplets with a silica nanoparticle coating layer was formed in the air.A stable Pickering emulsion containing PEI droplets was obtained after these ejected droplets were collected in a heated oil *** droplets turn into mm-sized particles after thermal curing in the *** diameter,PEI content,and silica content of the particles were systematically varied,and their CO_(2)absorption was measured as a function of *** regeneration of the particles enabled cyclic testing,revealing a CO_(2)absorption capacity of 6.5±0.5 mol kg^(−1)solid PEI in pure CO_(2)environments and 0.7±0.3 mol kg^(−1)solid PEI for direct air *** thousands of particles were produced per second at a rate of around 0.5 kg per hour,with a single *** process can be further scaled by *** complete toolbox for the design,fabrication,testing,and regeneration of functional hydrogel particles provides a powerful route toward novel solid sorbents for regenerative CO_(2)capture.

关键词： CO_(2)capture droplet hydrogel liquid jet particle steam regeneration

Maternal Mortality Rates among Im/Migrant Populations in the United States

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Open Journal of Obstetrics and Gynecology 2024年第8期14卷 1161-1175页

作者： tessa Peredy Mary Greenwald Katy Doughty Fachon Fiona Danaher Rashmi Jasrasaria Samantha Truong Annekathryn Goodman University of New England College of Osteopathic Medicine Biddeford ME United States Department of Obstetrics and Gynecology Massachusetts General Hospital Boston Boston MA United States Center for Immigrant Health Massachusetts General Hospital Boston Boston MA United States

Introduction: Maternal mortality rates have more than doubled in the U.S over the last two decades, making it one of the few places in the world where maternal mortality is increasing. Differences in maternal mortality among certain races and ethnicities are known but few studies examine maternal mortality among immigrants. Since immigrants represent 13.7% of the U.S. population, it is essential to examine immigrant subsets to understand maternal mortality among this vulnerable population. Methods: A literature search identified 318 articles on maternal mortality and immigrants, with 12 articles from the U.S. The keywords included maternal mortality, United States, migrants, asylum seekers, immigrants, and disparities. Maternal mortality statistics were obtained from the World Health Organization and Center for Disease Control. Results: Studies analyzed in this review found an overall lower maternal mortality rate among immigrant women compared to U.S.-born women, except for Hispanic immigrant women. Black women had the highest maternal mortality rate, regardless of immigration status. Conclusion: Although the literature points to lower maternal mortality among immigrants, the data is still somewhat mixed, making it challenging to draw comprehensive conclusions. Additional research examining maternal mortality among Im/migrants in the U.S. is needed to guide future training among healthcare professionals and policymakers.

关键词： Maternal Mortality Im/Migrant Reproductive Health United States

A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

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Neural Regeneration Research 2025年第1期20卷 291-304页

作者： Simeon C.Daeschler Katelyn J.W.So Konstantin Feinberg Marina Manoraj Jenny Cheung Jennifer Zhang Kaveh Mirmoeini JPaul Santerre tessa Gordon Gregory HBorschel SickKids Research Institute Neuroscience and Mental Health ProgramTorontoONCanada Institute of Biomaterials and Biomedical Engineering University of TorontoTorontoONCanada Indiana University School of Medicine IndianapolisINUSA Division of Plastic and Reconstructive Surgery the Hospital for Sick ChildrenTorontoONCanada Translational Biology and Engineering Program Ted Rogers Centre for Heart ResearchInstitute of Biomedical EngineeringFaculty of DentistryUniversity of TorontoTorontoONCanada

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong ***,there are no FDA-approved therapies available to promote nerve *** accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve *** authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug *** is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 *** and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible *** released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic *** its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

关键词： biodegradable local drug delivery nerve injury nerve regeneration nerve wrap tacrolimus