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Dirac Concentrations in a Chemostat Model of Adaptive Evolution(In honor of the immense scientific influence of Ham Brezis)

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Chinese Annals of Mathematics,Series B 2017年第2期38卷 513-538页

作者： alexander LORZ Benoit PERTHAME Cécile TAING Sorbonne Universits UPMC Univ Paris 06InriaLaboratoire Jacques-Louis Lions UM R CNRS 7598F75005 ParisFrance

This paper deals with a non-local parabolic equation of Lotka-Volterra type that describes the evolution of phenotypically structured populations. Nonlinearities appear in these systems to model interactions and competition phenomena leading to selection. In this paper, the equation on the structured population is coupled with a differential equation on the nutrient concentration that changes as the total population *** methods aimed at showing the convergence of the solutions to a moving Dirac mass are reviewed. Using either weak or strong regularity assumptions, the authors study the concentration of the solution. To this end, BV estimates in time on appropriate quantities are stated, and a constrained Hamilton-Jacobi equation to identify where the solutions concentrates as Dirac masses is derived.

关键词： Adaptive evolution, Asymptotic behaviour, Chemostat, Dirac concentrations,Hamilton-Jacobi equations, Lotka-Volterra equations, Viscosity solutions

Existence of positive solutions to some nonlinear equations on locally finite graphs

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Science China Mathematics 2017年第7期60卷 1311-1324页

作者： GRIGOR''YAN alexander LIN Yong YANG YunYan Department of Mathematics University of BielefeldBielefeld 33501Germany School of Mathematical Sciences and Laboratory of Pure Mathematics and Combinatorics Nankai UniversityTianjin 300071China Department of Mathematics Renmin University of ChinaBeijing 100872China

Let G =(V,E) be a locally finite graph,whose measure μ(x) has positive lower bound,and A be the usual graph *** the mountain-pass theorem due to Ambrosetti and Rabinowitz(1973),we establish existence results for some nonlinear equations,namely △u+hu=f(x,u),x∈*** particular,we prove that if h and f satisfy certain assumptions,then the above-mentioned equation has strictly positive ***,we consider existence of positive solutions of the perturbed equation △u+hu=f(x,u)+∈*** problems have been extensively studied on the Euclidean space as well as on Riemannian manifolds.

关键词： variational method mountain-pass theorem semi-linear equation on graphs

Coexisting charge density wave and ferromagnetic instabilities in monolayer InSe

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npj Computational Materials 2022年第1期8卷 1101-1109页

作者： Evgeny A.Stepanov Viktor Harkov Malte Rösner alexander I.Lichtenstein Mikhail I.Katsnelson alexander N.Rudenko CPHT CNRSEcole PolytechniqueInstitut Polytechnique de ParisF-91128PalaiseauFrance I.Institute of Theoretical Physics University of HamburgNotkestraße 922607HamburgGermany European X-Ray free-Electron Laser facility Holzkoppel 422869SchenefeldGermany Radboud University Institute for Molecules and Materials6525AJNijmegenThe Netherlands The Hamburg Centre for Ultrafast Imaging Luruper Chaussee 14922761HamburgGermany

Recently fabricated InSe monolayers exhibit remarkable characteristics that indicate the potential of this material to host a number of many-body *** this work,we systematically describe collective electronic effects in hole-doped InSe monolayers using advanced many-body *** this end,we derive a realistic electronic-structure model from first principles that takes into account the most important characteristics of this material,including a flat band with prominent van Hove singularities in the electronic spectrum,strong electron–phonon coupling,and weakly screened long-ranged Coulomb *** calculate the temperature-dependent phase diagram as a function of band filling and observe that this system is in a regime with coexisting charge density wave and ferromagnetic instabilities that are driven by strong electronic Coulomb *** regime can be achieved at realistic doping levels and high enough temperatures,and can be verified *** find that the electron–phonon interaction does not play a crucial role in these effects,effectively suppressing the local Coulomb interaction without changing the qualitative physical picture.

关键词： ferromagnetic charge wave

Computer-Aided Diagnosis for Tuberculosis Classification with Water Strider Optimization Algorithm

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Computer Systems Science & Engineering 2023年第8期46卷 1337-1353页

作者： José Escorcia-Gutierrez Roosvel Soto-Diaz Natasha Madera Carlos Soto francisco Burgos-florez alexander Rodríguez Romany f.Mansour Department of Computational Science and Electronic Universidad de la CostaCUCBarranquilla080002Colombia Biomedical Engineering Program Universidad Simón BolívarBarranquilla080002Colombia Mechatronics Engineering Program Universidad Simón BolívarBarranquilla080002Colombia Department of Medicine Universidad del NorteBarranquilla081007Colombia Department of Mathematics Faculty of ScienceNew Valley UniversityEl-Kharga72511Egypt

Computer-aided diagnosis(CAD)models exploit artificial intelligence(AI)for chest X-ray(CXR)examination to identify the presence of tuberculosis(TB)and can improve the feasibility and performance of CXR for TB screening and *** the same time,CXR interpretation is a time-consuming and subjective ***,high resemblance among the radiological patterns of TB and other lung diseases can result in ***,computer-aided diagnosis(CAD)models using machine learning(ML)and deep learning(DL)can be designed for screening TB *** this motivation,this article develops a Water Strider Optimization with Deep Transfer Learning Enabled Tuberculosis Classification(WSODTL-TBC)model on Chest X-rays(CXR).The presented WSODTL-TBC model aims to detect and classify TB on CXR ***,the WSODTL-TBC model undergoes image filtering techniques to discard the noise content and U-Net-based image ***,a pre-trained residual network with a two-dimensional convolutional neural network(2D-CNN)model is applied to extract feature *** addition,the WSO algorithm with long short-term memory(LSTM)model was employed for identifying and classifying TB,where the WSO algorithm is applied as a hyperparameter optimizer of the LSTM methodology,showing the novelty of the *** performance validation of the presented WSODTL-TBC model is carried out on the benchmark dataset,and the outcomes were investigated in many *** experimental development pointed out the betterment of the WSODTL-TBC model over existing algorithms.

关键词： Computer-aided diagnosis water strider optimization deep learning chest x-rays transfer learning

Magnetic Moment Tensor Potentials for collinear spin-polarized materials reproduce different magnetic states of bcc fe

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npj Computational Materials 2022年第1期8卷 107-112页

作者： Ivan Novikov Blazej Grabowski fritz Körmann alexander Shapeev Skolkovo Institute of Science and Technology Skolkovo Innovation CenterNobel St.3Moscow143026Russia Institute for Materials Science University of StuttgartPfaffenwaldring 5570569StuttgartGermany Computational Materials Design Max-Planck-Institut für Eisenforschung GmbHD-40237DüsseldorfGermany Materials Science and Engineering Delft University of Technology2628 CDDelftThe Netherlands

We present the magnetic Moment Tensor Potentials(mMTPs),a class of machine-learning interatomic potentials,accurately reproducing both vibrational and magnetic degrees of freedom as provided,e.g.,from first-principles *** accuracy is achieved by a two-step minimization scheme that coarse-grains the atomic and the spin *** performance of the mMTPs is demonstrated for the prototype magnetic system bcc iron,with applications to phonon calculations for different magnetic states,and molecular-dynamics simulations with fluctuating magnetic moments.

关键词： magnetic fluctuating states

Could wastewater analysis be a useful tool for China?——A review

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Journal of Environmental Sciences 2015年第1期27卷 70-79页

作者： Jianfa Gao Jake O'Brien foon Yin Lai alexander L.N.van Nuijs Jun He Jochen f.Mueller Jingsha Xu Phong K.Thai faculty of Science and Engineering University of Nottingham Ningbo China National Research Centre for Environmental Toxicology The University of Queensland Toxicological Center University of Antwerp

Analysing wastewater samples is an innovative approach that overcomes many limitations of traditional surveys to identify and measure a range of chemicals that were consumed by or exposed to people living in a sewer catchment area. first conceptualised in 2001, much progress has been made to make wastewater analysis（WWA） a reliable and robust tool for measuring chemical consumption and/or exposure. At the moment, the most popular application of WWA, sometimes referred as sewage epidemiology, is to monitor the consumption of illicit drugs in communities around the globe, including China. The approach has been largely adopted by law enforcement agencies as a device to monitor the temporal and geographical patterns of drug consumption. In the future, the methodology can be extended to other chemicals including biomarkers of population health（e.g. environmental or oxidative stress biomarkers, lifestyle indicators or medications that are taken by different demographic groups） and pollutants that people are exposed to（e.g. polycyclic aromatic hydrocarbons,perfluorinated chemicals, and toxic pesticides）. The extension of WWA to a huge range of chemicals may give rise to a field called sewage chemical-information mining（SCIM） with unexplored potentials. China has many densely populated cities with thousands of sewage treatment plants which are favourable for applying WWA/SCIM in order to help relevant authorities gather information about illicit drug consumption and population health status. However, there are some prerequisites and uncertainties of the methodology that should be addressed for SCIM to reach its full potential in China.

关键词： Drug consumption Wastewater analysis Biomarkers Population health

Precise Underground Observations of the Partial Solar Eclipse of 1 June 2011 Using a foucault Pendulum and a Very Light Torsion Balance

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International Journal of Astronomy and Astrophysics 2012年第4期2卷 204-209页

作者： Dimitrie Olenici alexander f. Pugach Astronomical Observatory Stefan cel Mare University Suceava Romania Main Astronomical Observatory of National Academy of Sciences Kiev Ukraine

Simultaneous observations of the solar eclipse on 06/01/2011 were carried out using a foucault pendulum and a torsion balance. The instruments were installed in a salt mine, where the interference was minimal. Both instruments clearly reacted to the eclipse. We conclude that these reactions should not be considered as being gravitational effects.

关键词： Solar Eclipse Allais Effect Torsion Balance

Resistance to receptor tyrosine kinase inhibition in cancer： molecular mechanisms and therapeutic strategies

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frontiers of Medicine 2015年第2期9卷 134-138页

作者： Peter B. alexander Xiao-fan Wang Department of Pharmacology and Cancer Biology Duke University Medical Center Durham NC 27710 USA

Drug resistance is a major factor that limits the efficacy of targeted cancer therapies. In this review, we discuss the main known mechanisms of resistance to receptor tyrosine kinase inhibitors, which are the most prevalent class of targeted therapeutic agent in current clinical use. Here we focus on bypass track resistance, which involves the activation of alternate signaling molecules by tumor cells to bypass inhibition and maintain signaling output, and consider the problems of signaling pathway redundancy and how the activation of different receptor tyrosine kinases translates into intracellular signal transduction in different cancer types. This information is presented in the context of research strategies for the discovery of new targets for pharmacological intervention, with the goal of overcoming resistance in order to improve patient outcomes.

关键词： targeted therapy drug resistance receptor tyrosine kinases cancer

Shock response mitigation of a large-scale structure by modal energy redistribution facilitated by a strongly nonlinear absorber

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Acta Mechanica Sinica 2022年第6期38卷 39-54,I0001页

作者： Xiang Li lireza Mojahed Li-Qun Chen Lawence A.Bergman alexander f.Vakakis Shanghai Institute of Applied Mathematies and Mechanics School of Mechanies and Engineering ScienceShanghai University Shanghai 200444China Aerospace Engineering Universityof llinois UrbanaIL61801USA Mechanical Science and Engineering University of linois Urbana IL 61801USA

A lightweight geometrically nonlinear attachment,the strongly nonlinear absorber(SNA),is adopted to suppress the shock response of a linear,large-scale nine-story *** role of the SNA is not only to dissipate but also to redistribute the shock energy among the modes of the *** this study,single-and two-degree-of-freedom(SDOf and Two-DOf)SNAs are *** quantitative results for shock energy redistribution indicate that with strong geometric nonlinearity,one can achieve low-to-high frequency nonlinear targeted energy transfer in this ***,the percentages of shock energy dissipated by higher structural modes for the cases of locked SNA,SDOf SNA,and Two-DOf SNA are 0.08%,0.43%,and 30.04%,*** results indicate that the Two-DOf SNA is capable of rapidly scattering far more energy to much higher frequencies than the SDOf SNA,thereby more quickly reducing the shock response of the primary *** robustness of the performance of the SNAs is also studied for varying shock intensities,where the Two-DOf SNA is shown to be significantly more robust at scattering shock energy from low to high ***,an effective damping measure is employed to verify and quantify the redistribution of the modal energies in the primary *** potential applications of this new passive shock mitigation method are discussed.

关键词： Strongly nonlinear absorber Shock response mitigation Targeted energy transfer Modal energy redistribution Geometric nonlinearity