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2015

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Articles 601 - 618 of 618

Full-Text Articles in Physical Sciences and Mathematics

A Survey On Reverse Carleson Measures, Emmanuel Fricain, Andreas Hartmann, William T. Ross Jan 2015

A Survey On Reverse Carleson Measures, Emmanuel Fricain, Andreas Hartmann, William T. Ross

Department of Math & Statistics Faculty Publications

This is a survey on reverse Carleson measures for various Hilbert spaces of analytic functions. These spaces include the Hardy, Bergman, certain harmonically weighted Dirichlet, Paley-Wiener, Fock, model (backward shift invariant), and de Branges-Rovnyak spaces. The reverse Carleson measure for backward shift invariant subspaces in the non-Hilbert situation is new.

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Pulses And Snakes In Ginzburg-Landau Equation, S.C. Mancas, Roy S. Choudhury Jan 2015

Pulses And Snakes In Ginzburg-Landau Equation, S.C. Mancas, Roy S. Choudhury

Publications

Using a variational formulation for partial differential equations combined with numerical simulations on ordinary differential equations (ODEs), we find two categories (pulses and snakes) of dissipative solitons, and analyze the dependence of both their shape and stability on the physical parameters of the cubic-quintic Ginzburg–Landau equation (CGLE). In contrast to the regular solitary waves investigated in numerous integrable and non-integrable systems over the last three decades, these dissipative solitons are not stationary in time. Rather, they are spatially confined pulse-type structures whose envelopes exhibit complicated temporal dynamics. Numerical simulations reveal very interesting bifurcations sequences as the parameters of the CGLE …

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Mathematics Education In A Multilingual And Multicultural Environment, Anjum Halai, Richard Barwell Jan 2015

Mathematics Education In A Multilingual And Multicultural Environment, Anjum Halai, Richard Barwell

Book Chapters / Conference Papers

No abstract provided.

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Modeling Human Gaming Playing Behavior And Reward/Penalty Mechanism Using Discrete Event Simulation (Des), Christina M. Frederick, Michael Fitzgerald, Dahai Liu, Yolanda Ortiz, Christopher Via, Shawn Doherty, Jason P. Kring Jan 2015

Modeling Human Gaming Playing Behavior And Reward/Penalty Mechanism Using Discrete Event Simulation (Des), Christina M. Frederick, Michael Fitzgerald, Dahai Liu, Yolanda Ortiz, Christopher Via, Shawn Doherty, Jason P. Kring

Publications

Humans are remarkably complex and unpredictable; however, while predicting human behavior can be problematic, there are methods such as modeling and simulation that can be used to predict probable futures of human decisions. The present study analyzes the possibility of replacing human subjects with data resulting from pure models. Decisions made by college students in a multi-level mystery-solving game under 3 different gaming conditions are compared with the data collected from a predictive sequential Markov-Decision Process model. In addition, differences in participants’ data influenced by the three different conditions (additive, subtractive, control) were analyzed. The test results strongly suggest that …

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Prognostic Value Of Estimating Functional Capacity With The Use Of The Duke Activity Status Index In Stable Patients With Chronic Heart Failure, Justin L. Grodin, Muhammad Hammadah, Yiying Fan, Stanley L. Hazen, W.H. Wilson Tang Jan 2015

Prognostic Value Of Estimating Functional Capacity With The Use Of The Duke Activity Status Index In Stable Patients With Chronic Heart Failure, Justin L. Grodin, Muhammad Hammadah, Yiying Fan, Stanley L. Hazen, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

BACKGROUND: Over the years, several methods have been developed to reliably quantify functional capacity in patients with heart failure. Few studies have investigated the prognostic value of these assessment tools beyond cardiorenal prognostic biomarkers in stable patients with chronic heart failure. METHODS AND RESULTS: We administered the Duke Activity Status Index (DASI) questionnaire, a self-assessment tool comprising 12 questions for estimating functional capacity, to 1,700 stable nonacute coronary syndrome patients with history of heart failure who underwent elective diagnostic coronary angiography with 5-year follow-up of all-cause mortality. In a subset of patients (n = 800), B-type natriuretic peptide (BNP) was …

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Lattice Polytopes In Coding Theory, Ivan Soprunov Jan 2015

Lattice Polytopes In Coding Theory, Ivan Soprunov

Mathematics and Statistics Faculty Publications

In this paper we discuss combinatorial questions about lattice polytopes motivated by recent results on minimum distance estimation for toric codes. We also prove a new inductive bound for the minimum distance of generalized toric codes. As an application, we give new formulas for the minimum distance of generalized toric codes for special lattice point configurations.

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Rayleigh Approximation To Ground State Of The Bose And Coulomb Glasses, Shawn D. Ryan, V. Mityushev, V. M. Vinokur, L. Berlyand Jan 2015

Rayleigh Approximation To Ground State Of The Bose And Coulomb Glasses, Shawn D. Ryan, V. Mityushev, V. M. Vinokur, L. Berlyand

Mathematics and Statistics Faculty Publications

Glasses are rigid systems in which competing interactions prevent simultaneous minimization of local energies. This leads to frustration and highly degenerate ground states the nature and properties of which are still far from being thoroughly understood. We report an analytical approach based on the method of functional equations that allows us to construct the Rayleigh approximation to the ground state of a two-dimensional (2D) random Coulomb system with logarithmic interactions. We realize a model for 2D Coulomb glass as a cylindrical type II superconductor containing randomly located columnar defects (CD) which trap superconducting vortices induced by applied magnetic field. Our …

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A Mapping Theorem For Topological Complexity, Mark Grant, Gregory Lupton, John Oprea Jan 2015

A Mapping Theorem For Topological Complexity, Mark Grant, Gregory Lupton, John Oprea

Mathematics and Statistics Faculty Publications

We give new lower bounds for the (higher) topological complexity of a space, in terms of the Lusternik-Schnirelmann category of a certain auxiliary space. We also give new lower bounds for the rational topological complexity of a space, and more generally for the rational sectional category of a map, in terms of the rational category of a certain auxiliary space. We use our results to deduce consequences for the global (rational) homotopy structure of simply connected, hyperbolic finite complexes.

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A Remark On Estimating The Mean Of A Normal Distribution With Known Coefficient Of Variation, Rasul A. Khan Jan 2015

A Remark On Estimating The Mean Of A Normal Distribution With Known Coefficient Of Variation, Rasul A. Khan

Mathematics and Statistics Faculty Publications

Let X1, X2, …, Xn be iid N(μ, aμ2) (a>0) random variables with an unknown mean μ>0 and known coefficient of variation (CV) √a. The estimation of μ is revisited and it is shown that a modified version of an unbiased estimator of μ [cf. Khan RA. A note on estimating the mean of a normal distribution with known CV. J Am Stat Assoc. 1968;63:1039–1041] is more efficient. A certain linear minimum mean square estimator of Gleser and Healy [Estimating the mean of a normal distribution with known CV. J Am Stat Assoc. 1976;71:977–981] is also modified and …

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Cd4 Deficit And Tuberculosis Risk Persist With Delayed Antiretroviral Therapy: 5-Year Data From Cipra Ht-001, S. E. Collins, M.A. Jean Juste, S. P. Koenig, R. Secours, O. Ocheretina, D. Bernard, C. Riviere, M. Calnan, A. Dunning, Sandra M. Hurtado Rua, W. D. Johnson Jr., J. W. Pape, D. W. Fitzgerald, P. Severe Jan 2015

Cd4 Deficit And Tuberculosis Risk Persist With Delayed Antiretroviral Therapy: 5-Year Data From Cipra Ht-001, S. E. Collins, M.A. Jean Juste, S. P. Koenig, R. Secours, O. Ocheretina, D. Bernard, C. Riviere, M. Calnan, A. Dunning, Sandra M. Hurtado Rua, W. D. Johnson Jr., J. W. Pape, D. W. Fitzgerald, P. Severe

Mathematics and Statistics Faculty Publications

SETTING: Port-au-Prince, Haiti. OBJECTIVE: To determine long-term effects of early vs. delayed initiation of antiretroviral therapy (ART) on immune recovery and tuberculosis (TB) risk in human immunodeficiency virus (HIV) infected individuals. DESIGN: Open-label randomized controlled trial of immediate ART in HIV-infected adults with CD4 counts between 200 and 350 cells/mm(3) vs. deferring ART until the CD4 count was <200 cells/mm(3). The primary comparisons were CD4 counts over time and risk for incident TB, with 5 years of follow-up. RESULTS: A total of 816 participants were enrolled, with 408 in each treatment arm. The early treatment group started ART within 2 weeks, while the deferred treatment group started ART a median of 1.3 years after enrollment. After 5 years, the mean CD4 count in the early treatment group was significantly higher than in the deferred treatment group (496 cells/mm(3), 95% confidence interval [CI] 477-515 vs. 373 cells/mm(3), 95%CI 357-389; P < 0.0001). TB risk was higher in the deferred treatment group (unadjusted HR 2.41, 95%CI 1.56-3.74; P < 0.0001) and strongly correlated with lower CD4 counts in time-dependent multivariate analysis. CONCLUSION: Delays in ART initiation for HIV-infected adults with CD4 counts of 200-350 cells/mm(3) can result in long-term immune dysfunction and persistent increased risk for TB. TRIAL REGISTRATION: ClinicalTrials.gov NCT00120510.

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A Robust Deep Model For Improved Classification Of Ad/Mci Patients, Feng Li, Loc Tran, Kim-Han Thung, Shuiwang Ji, Dinggang Shen, Jiang Li Jan 2015

A Robust Deep Model For Improved Classification Of Ad/Mci Patients, Feng Li, Loc Tran, Kim-Han Thung, Shuiwang Ji, Dinggang Shen, Jiang Li

Electrical & Computer Engineering Faculty Publications

Accurate classification of Alzheimer's disease (AD) and its prodromal stage, mild cognitive impairment (MCI), plays a critical role in possibly preventing progression of memory impairment and improving quality of life for AD patients. Among many research tasks, it is of a particular interest to identify noninvasive imaging biomarkers for AD diagnosis. In this paper, we present a robust deep learning system to identify different progression stages of AD patients based on MRI and PET scans. We utilized the dropout technique to improve classical deep learning by preventing its weight coadaptation, which is a typical cause of overfitting in deep learning. …

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On Algebras Which Are Inductive Limits Of Banach Spaces, Daniel Alpay, Guy Salomon Jan 2015

On Algebras Which Are Inductive Limits Of Banach Spaces, Daniel Alpay, Guy Salomon

Mathematics, Physics, and Computer Science Faculty Articles and Research

We introduce algebras which are inductive limits of Banach spaces and carry inequalities which are counterparts of the inequality for the norm in a Banach algebra. We then define an associated Wiener algebra, and prove the corresponding version of the well-known Wiener theorem. Finally, we consider factorization theory in these algebra, and in particular, in the associated Wiener algebra.

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Measuring Longitudinal Myelin Water Fraction In New Multiple Sclerosis Lesions, Wendy S. Vargas, Elizabeth Monohan, Sneha Pandya, Ashish Raj, Timothy Vartanian, Thanh D. Nguyen, Sandra M. Hurtado Rua, Susan A. Gauthier Jan 2015

Measuring Longitudinal Myelin Water Fraction In New Multiple Sclerosis Lesions, Wendy S. Vargas, Elizabeth Monohan, Sneha Pandya, Ashish Raj, Timothy Vartanian, Thanh D. Nguyen, Sandra M. Hurtado Rua, Susan A. Gauthier

Mathematics and Statistics Faculty Publications

Objectives: Investigating the potential of myelin repair strategies in multiple sclerosis (MS) requires an understanding of myelin dynamics during lesion evolution. The objective of this study is to longitudinally measure myelin water fraction (MWF), an MRI biomarker of myelin, in new MS lesions and to identify factors that influence their subsequent myelin content. Methods:Twenty-three MS patients were scanned with whole-brain Fast Acquisition with Spiral Trajectory and T2prep (FAST-T2) MWF mapping at baseline and median follow-up of 6 months. Eleven healthy controls (HC) confirmed the reproducibility of FAST-T2 in white matter regions of interests (ROIs) similar to a lesion size. A …

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Symmetries Of Monocoronal Tilings, Dirk Frettlöh, Alexey Garber Jan 2015

Symmetries Of Monocoronal Tilings, Dirk Frettlöh, Alexey Garber

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

The vertex corona of a vertex of some tiling is the vertex together with the adjacent tiles. A tiling where all vertex coronae are congruent is called monocoronal. We provide a classification of monocoronal tilings in the Euclidean plane and derive a list of all possible symmetry groups of monocoronal tilings. In particular, any monocoronal tiling with respect to direct congruence is crystallographic, whereas any monocoronal tiling with respect to congruence (reflections allowed) is either crystallographic or it has a one-dimensional translation group. Furthermore, bounds on the number of the dimensions of the translation group of monocoronal tilings in higher …

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Asymptotic Analysis Of A Magnetized Target Fusion Reactor, Michael R. Lindstrom Jan 2015

Asymptotic Analysis Of A Magnetized Target Fusion Reactor, Michael R. Lindstrom

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Nonlinear conservation laws with moving boundaries often arise in applications such as gas dynamics and more recently in the context of nuclear fusion reactors. Gaining insight into the nature of solutions to such models and their dependence upon design parameters is often done numerically. We use formal asymptotics to study a model of a magnetized target fusion reactor for producing energy. We will asymptotically solve the compressible Euler equations with two free moving boundaries, with an algebraic coupling of fluid pressure at one of the free boundaries. The model consists of an intense pressure being imparted on the boundary of …

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Connections Of Zero Curvature And Bäcklund Transformations, Paul Bracken Jan 2015

Connections Of Zero Curvature And Bäcklund Transformations, Paul Bracken

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Zero curvature connections in a principal bundle are introduced. It is shown that such connections are very useful in formulating the Bäcklund problem and in constructing transformations. A general technique can be proposed for producing such transformations by defining the relevant connection coefficients appropriately. Finally, several applications of this work to various types of nonlinear partial differential equations will be presented.

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Teac 451p: Learning And Teaching Principles And Practices (Secondary Mathematics)—A Peer Review Of Teaching Project Benchmark Portfolio, Lorraine Males Jan 2015

Teac 451p: Learning And Teaching Principles And Practices (Secondary Mathematics)—A Peer Review Of Teaching Project Benchmark Portfolio, Lorraine Males

UNL Faculty Course Portfolios

The goal of my peer review portfolio was to better understand how to improve students' learning of how to teach secondary mathematics in reform-oriented ways. Most students that pursue admission into the Secondary Mathematics Teacher Education Program have little to no experience learning mathematics in reform-oriented ways. These preservice teachers (PSTs) were “successful” in mathematics courses in middle and high school, most of them taking honors or accelerated courses. However, many of these PSTs did not have opportunities to engage as active participants in their own learning and develop complex cognitive skills and processes, the focus of reform-oriented instruction. This …

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Critical Controlled Branching Processes And Their Relatives, George Yanev Jan 2015

Critical Controlled Branching Processes And Their Relatives, George Yanev

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

This survey aims at collecting and presenting results for one-type, discrete time branching processes with random control functions. In particular, the subclass of critical migration processes with different regimes of immigration and emigration is reviewed in detail. Critical controlled branching processes with continuous state space are also discussed.

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