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Evaluation of a deep learning supported remote diagnosis model for identification of diabetic retinopathy using wide-field Optomap

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Annals of Eye Science 2022年第2期7卷 93-104页

作者： Terry Lee Mingzhe Hu Qitong Gao Joshua Amason Durga Borkar David D’Alessio Michael Canos Afreen Shariff Miroslav Pajic majda hadziahmetovic Department of Ophthalmology Duke University Medical CenterDurhamNCUSA Department of Electrical and Computer Engineering Duke UniversityDurhamNCUSA Department of Endocrinology Duke University Medical CenterDurhamNCUSA

Background:We test a deep learning(DL)supported remote diagnosis approach to detect diabetic retinopathy(DR)and other referable retinal pathologies using ultra-wide-field(UWF)***:Prospective,non-randomized study involving diabetic patients seen at endocrinology ***-expert imagers were trained to obtain non-dilated images using UWF *** were graded by two retina specialists and classified as DR or incidental retinal ***’s kappa was used to test the agreement between the remote diagnosis and the gold standard exam.A novel DL model was trained to identify the presence or absence of referable pathology,and sensitivity,specificity and area under the receiver operator characteristics curve(AUROC)were used to assess its ***:A total of 265 patients were enrolled,of which 241 patients were imaged(433 eyes).The mean age was 50±17 years,45%of patients were female,34%had a diagnosis of diabetes mellitus type 1,and 66%of type *** average Hemoglobin A1c was 8.8±2.3%,and 81%were on *** the 433 images,404(93%)were gradable,64 patients(27%)were referred to a retina specialist,and 46(19%)were referred to comprehensive ophthalmologist for a referable retinal pathology on remote ***’s kappa was 0.58,indicating moderate *** DL algorithm achieved an accuracy of 82.8%(95%CI:80.3-85.2%),a sensitivity of 81.0%(95%CI:78.5-83.6%),specificity of 73.5%(95%CI:70.6-76.3%),and AUROC of 81.0%(95%CI:78.5-83.6%).Conclusions:UWF Primary can be used in the non-ophthalmology setting to screen for referable retinal pathology and can be successfully supported by an automated algorithm for image classification.

关键词： Retina screening imaging deep learning(DL) diabetic retinopathy(DR)

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Invariant Measures and Asymptotic Gaussian Bounds for Normal Forms of Stochastic Climate Model

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Chinese Annals of Mathematics,Series B 2011年第3期32卷 343-368页

作者： Yuan YUAN Andrew J. majda Department of Mathematics Courant Institute New York University 251 Mercer Street New York NY 10012 USA Department of Mathematics and Center for Atmospheric Ocean Sciences Courant Institute New York University 251 Mercer Street New York NY 10012 USA

The systematic development of reduced low-dimensional stochastic climate models from observations or comprehensive high dimensional climate models is an important topic for atmospheric low-frequency variability,climate sensitivity,and improved extended range ***,techniques from applied mathematics have been utilized to systematically derive normal forms for reduced stochastic climate models for low-frequency *** was shown that dyad and multiplicative triad interactions combine with the climatological linear operator interactions to produce a normal form with both strong nonlinear cubic dissipation and Correlated Additive and Multiplicative(CAM) stochastic *** probability distribution functions(PDFs) of low frequency climate variables exhibit small but significant departure from Gaussianity but have asymptotic tails which decay at most like a ***,rigorous upper bounds with Gaussian decay are proved for the invariant measure of general normal form stochastic *** Gaussian lower bounds are also established under suitable hypotheses.

关键词： Reduced stochastic climate model Invariant measure Fokker-Planck equation Comparison principle Global estimates of probability density function

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Zonal Jet Creation from Secondary Instability of Drift Waves for Plasma Edge Turbulence

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Chinese Annals of Mathematics,Series B 2019年第6期40卷 869-890页

作者： Di QI Andrew J.majda Department of Mathematics and Center for Atmosphere and Ocean Science Courant Institute of Mathematical Sciences New York University

A new strategy is presented to explain the creation and persistence of zonal flows widely observed in plasma edge *** core physics in the edge regime of the magnetic-fusion tokamaks can be described qualitatively by the one-state modified Hasegawa-Mima(MHM for short)model,which creates enhanced zonal flows and more physically relevant features in comparison with the familiar Charney-Hasegawa-Mima(CHM for short)model for both plasma and geophysical *** generation mechanism of zonal jets is displayed from the secondary instability analysis via nonlinear interactions with a background base *** exponential growth in the zonal modes is induced due to a non-zonal drift wave base state in the MHM model,while stabilizing damping effect is shown with a zonal flow base *** with the selective decay effect from the dissipation,the secondary instability offers a complete characterization of the convergence process to the purely zonal *** numerical simulations with and without dissipation are carried out to confirm the instability *** shows clearly the emergence of a dominant zonal flow from pure non-zonal drift waves with small perturbation in the initial *** comparison,the CHM model does not create instability in the zonal modes and usually converges to homogeneous turbulence.

关键词： Zonal flow generation Drift wave turbulence Secondary instability Modified Hasegawa-Mima model

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Optimal Systematic Determination of Models' Base for Multimodel Representation: Real Time Application

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International Journal of Automation and computing 2014年第6期11卷 644-652页

作者： majda Ltaief Anis Messaoud Ridha Ben Abdennour Research Unit of Numerical Control of Industrial Processes National School of Engineers of Gabes University of Gabes St Omar Ibn El-Khattab6029 Gabes Tunisia

The multimodel approach is a powerful and practical tool to deal with analysis, modeling, observation, emulation and control of complex systems. In the modeling framework, we propose in this paper a new method for optimal systematic determination of models base for multimodel representation. This method is based on the classification of data set picked out of the considered system. The obtained cluster centers are exploited to provide the weighting functions and to deduce the corresponding dispersions and their models base. A simulation example and an experimental validation on a semi-batch reactor are presented to evaluate the effectiveness of the proposed method.

关键词： Multimodel approach identification classification weighting functions complex systems chemical reactor

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Non-gaussian Test Models for Prediction and State Estimation with Model Errors

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Chinese Annals of Mathematics,Series B 2013年第1期34卷 29-64页

作者： Michal BRANICKI Nan CHEN Andrew J.majda Department of Mathematics and Center for Atmosphere Ocean Science Courant Institute of Mathematical SciencesNew York University

Turbulent dynamical systems involve dynamics with both a large dimensional phase space and a large number of positive Lyapunov exponents. Such systems are ubiqui- tous in applications in contemporary science and engineering where the statistical ensemble prediction and the real time filtering/state estimation are needed despite the underlying complexity of the system. Statistically exactly solvable test models have a crucial role to provide firm mathematical underpinning or new algorithms for vastly more complex scien- tific phenomena. Here, a class of statistically exactly solvable non-Gaussian test models is introduced, where a generalized Feynman-Ka~ formulation reduces the exact behavior of conditional statistical moments to the solution to inhomogeneous Fokker-Planck equations modified by linear lower order coupling and source terms. This procedure is applied to a test model with hidden instabilities and is combined with information theory to address two important issues in the contemporary statistical prediction of turbulent dynamical systems： the coarse-grained ensemble prediction in a perfect model and the improving long range forecasting in imperfect models. The models discussed here should be use- ful for many other applications and algorithms for the real time prediction and the state estimation.

关键词： Prediction Model error Information theory Feynman-Kac framework Fokker planck Turbulent dynamical systems

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New Results on Discrete-time Delay Systems Identification

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International Journal of Automation and computing 2012年第6期9卷 570-577页

作者： Sada Bedoui majda Ltaief Kamel Abderrahim Department of Electrical and Automation Engineering National Engineering School of GabesUniversity of Gabes

A new approach for simultaneous online identification of unknown time delay and dynamic parameters of discrete-time delay systems is proposed in this *** proposed algorithm involves constructing a new generalized regression vector and defining the time delay and the rational dynamic parameters in the same *** gradient algorithm is used to deal with the identification *** effectiveness of this method is illustrated through simulation.

关键词： Time delay identification gradient method discrete-time delay system iterative algorithm.

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Spatial Localization for Nonlinear Dynamical Stochastic Models for Excitable Media

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Chinese Annals of Mathematics,Series B 2019年第6期40卷 891-924页

作者： Nan CHEN Andrew J.majda Xin T.TONG Department of Mathematics University of Wisconsin-MadisonWI53705USA Department of Mathematics and Center for Atmosphere Ocean Science Courant Institute of Mathematical SciencesNew York UniversityNew YorkNY10012USA Center for Prototype Climate Modeling New York University AbuDhabiSaadiyat IslandAbuDhabiUAE Department of Mathematics National University of SingaporeSingapore 119076Singapore

Nonlinear dynamical stochastic models are ubiquitous in different *** statistical properties are often of great interest,but are also very challenging to *** excitable media models belong to such types of complex systems with large state dimensions and the associated covariance matrices have localized *** this article,a mathematical framework to understand the spatial localization for a large class of stochastically coupled nonlinear systems in high dimensions is *** mathematical analysis shows that the local effect from the diffusion results in an exponential decay of the components in the covariance matrix as a function of the distance while the global effect due to the mean field interaction synchronizes different components and contributes to a global *** analysis is based on a comparison with an appropriate linear surrogate model,of which the covariance propagation can be computed *** important applications of these theoretical results are *** are the spatial averaging strategy for efficiently sampling the covariance matrix and the localization technique in data *** examples of a linear model and a stochastically coupled Fitz Hugh-Nagumo model for excitable media are adopted to validate the theoretical *** latter is also used for a systematical study of the spatial averaging strategy in efficiently sampling the covariance matrix in different dynamical regimes.

关键词： Large state dimensions Diffusion Mean field interaction Spatial averaging strategy Efficiently sampling

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How rotational speed of planetary ball mill and polymer load influence the performance and water vapor sorption in solid dispersions composed of tadalafil and soluplus

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Particuology 2023年第2期73卷 37-46页

作者： Karol Kubat Anna Krupa Witold Brniak Agnieszka Węgrzyn Dorota majda Agata Bogdał Hubert Harańczyk Department of Medical Physics Faculty of PhysicsInstitute of PhysicsJagiellonian UniversityCracowPoland Department of Pharmaceutical Technology and Biopharmaceutics Faculty of PharmacyCollegium MedicumJagiellonian UniversityCracowPoland Faculty of Chemistry Jagiellonian UniversityCracowPoland

The presence of residual water may deteriorate the performance of amorphous solid dispersions prepared by ball milling,affecting molecular mobility,crystallinity,particle size and finally,the drug dissolution *** the stability of these metastable systems depend on both formulation and process variables,the aim of this study was to assess for the first time,the impact that the polymer load and the rotational speed applied upon high energy ball milling could have on the performance of binary co-milled solid dispersions composed of tadalafil(a hydrophobic crystalline drug)and Soluplus(an amphiphilic,hygroscopic amorphous polymer).Each of these variables was tested at three *** electron microscopy,laser diffraction and X-ray powder diffraction were used to analyze morphology,particle size distribution and crystallinity of ball milled formulations *** studies were also carried *** tools of applied physics,namely solid state 1H NMR and relaxometry were used to assess the structure and water mobility upon gaseous phase hydration on *** was shown that both tested variables determined the particle size of the *** the rotational speed of 400 rpm was used,all solid dispersion were XRD-amorphous,but to ensure the immediate release of tadalafil its micellar solubilization in Soluplus was *** the formulation was exposed to water vapor,the hydration level increased with an increasing polymer load as ***,the rotational speed governed the space available for the adsorption of water molecules and their organization in a monolayer or *** behavior may have impact on the kinetics of the amorphous drug recrystallization,and finally deteriorate its dissolution.

关键词： Tadalafil Soluplus Solid dispersion Relaxation time Milling NMR

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ON THE ACCURACY OF THE LEAST SQUARES AND THE TOTAL LEAST SQUARES METHODS

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Numerical Mathematics A Journal of Chinese Universities(English Series) 1994年第2期3卷 135-153页

作者：魏木生 George majda Department of Mathematics East China Normal UniversityShanghai 200062 China. Department of Mathematics The Ohio State University ColumbusOH 43210 USA.

Consider solving an overdetermined system of linear algebraic equations by both the least squares method (LS) and the total least squares method (TLS). Extensive published computational evidence shows that when the original system is consistent. one often obtains more accurate solutions by using the TLS method rather than the LS method. These numerical observations contrast with existing analytic perturbation theories for the LS and TLS methods which show that the upper bounds for the LS solution are always smaller than the corresponding upper bounds for the TLS solutions. In this paper we derive a new upper bound for the TLS solution and indicate when the TLS method can be more accurate than the LS *** applied problems in signal processing lead to overdetermined systems of linear equations where the matrix and right hand side are determined by the experimental observations (usually in the form of a lime series). It often happens that as the number of columns of the matrix becomes larger, the

关键词： Least squares total least squares accuracy rank deficient.

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Parvovirus B19 and Pregnant Women: A Bibliographic Review

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Open Journal of Obstetrics and Gynecology 2021年第11期11卷 1543-1564页

作者： majda Bouraddane Karima Warda Said Zouhair Laboratory of Microbiology-Virology Department of Biology Faculty of Medicine and Pharmacy University Cadi Ayyad Marrakech Morocco Laboratory of Bacteriology-Virology Avicenne Military Hospital Marrakech (HMA) Morocco

Primary infection with parvovirus B19 is an uncommon but serious and treatable cause of chronic anemia in immuno compromised hosts. Widely distributed, it is responsible for a wide range of clinical manifestations, the characteristics and outcome of which depend on the interaction between the viral properties and the physiological and immune status of the infected individuals. Infection during pregnancy can result in fetal anemia, abortion, and hydrops. Pregnancy does not appear to affect the course of the infection, but the infection may affect the pregnancy. The diagnosis of B19V can be made by serological and molecular investigation of the mother, fetus and newborn. In these conditions, it seemed necessary for us to answer in this article the various questions raised by the occurrence of a contagion and/or an infection with Parvovirus B19 during pregnancy. Our objective was to determine at first the nature and the main characteristics of Parvovirus B19 as well as its propagation during the pregnancy and to show its risk for the pregnant woman and her fetus. The importance of the subject is proven by the data on the spread and incidence of the virus. Worldwide, the focus on pregnancy is due to the additional potentially fatal effects on the fetus. This document covers the important aspects of a medical investigation: causes, symptoms, tests and diagnosis.

关键词： Parvovirus B19 Pregnant Women Clinical Manifestations Fetal Death Hydrops Fetalis

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