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Articles 19741 - 19770 of 27476

Full-Text Articles in Physical Sciences and Mathematics

Infrared Spectroscopy In Combination With Advanced Statistical Methods For Distinguishing Viral Infected Biological Cells, Tian Tang Nov 2008

Infrared Spectroscopy In Combination With Advanced Statistical Methods For Distinguishing Viral Infected Biological Cells, Tian Tang

Mathematics Theses

Fourier Transform Infrared (FTIR) microscopy is a sensitive method for detecting difference in the morphology of biological cells. In this study FTIR spectra were obtained for uninfected cells, and cells infected with two different viruses. The spectra obtained are difficult to discriminate visually. Here we apply advanced statistical methods to the analysis of the spectra, to test if such spectra are useful for diagnosing viral infections in cells. Logistic Regression (LR) and Partial Least Squares Regression (PLSR) were used to build models which allow us to diagnose if spectral differences are related to infection state of the cells. A three-fold, …

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Best Proximity Pairs For Upper Semicontinuous Set-Valued Maps In Hyperconvex Metric Spaces, Alireza Amini-Harandi, Ali P. Farajzadeh, Donal O'Regan, Ravi P. Agarwal Nov 2008

Best Proximity Pairs For Upper Semicontinuous Set-Valued Maps In Hyperconvex Metric Spaces, Alireza Amini-Harandi, Ali P. Farajzadeh, Donal O'Regan, Ravi P. Agarwal

Mathematics and System Engineering Faculty Publications

A best proximity pair for a set-valued map F : A → B with respect to a map g : A → A is defined, and new existence theorems of best proximity pairs for upper semicontinuous set-valued maps with respect to a homeomorphism are proved in hyperconvex metric spaces.

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Metric Regularity Of Mappings And Generalized Normals To Set Images, Boris S. Mordukhovich, Nguyen Mau Nam, Bingwu Wang Nov 2008

Metric Regularity Of Mappings And Generalized Normals To Set Images, Boris S. Mordukhovich, Nguyen Mau Nam, Bingwu Wang

Mathematics Research Reports

The primary goal of this paper is to study some notions of normals to nonconvex sets in finite-dimensional and infinite-dimensional spaces and their images under single-valued and set-valued mappings. The main motivation for our study comes from variational analysis and optimization, where the problems under consideration play a crucial role in many important aspects of generalized differential calculus and applications. Our major results provide precise equality formulas (sometimes just efficient upper estimates) allowing us to compute generalized normals in various senses to direct and inverse images of nonconvex sets under single-valued and set-valued mappings between Banach spaces. The main tools …

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Selective Screenability In Topological Groups, Liljana Babinkostova Nov 2008

Selective Screenability In Topological Groups, Liljana Babinkostova

Mathematics Faculty Publications and Presentations

We examine the selective screenability property in topological groups. In the metrizable case we also give characterizations of Sc(Onbd,O) and Smirnov-Sc(Onbd,O) in terms of the Haver property and finitary Haver property respectively relative to left-invariant metrics. We prove theorems stating conditions under which Sc(Onbd,O) is preserved by products. Among metrizable groups we characterize the countable dimensional ones by a natural game.

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Prey Behavior, Age-Dependent Vulnerability, And Predation Rates, Susan Lingle, Alex Feldman, Mark S. Boyce, W. Finbarr Wilson Nov 2008

Prey Behavior, Age-Dependent Vulnerability, And Predation Rates, Susan Lingle, Alex Feldman, Mark S. Boyce, W. Finbarr Wilson

Mathematics Faculty Publications and Presentations

Variation in the temporal pattern of vulnerability can provide important insights into predator-prey relationships and the evolution of antipredator behavior. We illustrate these points with a system that has coyotes (Canis latrans) as a predator and two species of congeneric deer (Odocoileus spp.) as prey. The deer employ different antipredator tactics (aggressive defense vs. flight) that result in contrasting patterns of age-dependent vulnerability in their probability of being captured when encountered by coyotes.We use longterm survival data and a simple mathematical model to show that (1) species differences in age-dependent vulnerability are reflected in seasonal predation rates …

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Asymptotic Behavior Of Linearized Viscoelastic Flow Problem, Yinnian He, Yi Li Nov 2008

Asymptotic Behavior Of Linearized Viscoelastic Flow Problem, Yinnian He, Yi Li

Yi Li

In this article, we provide some asymptotic behaviors of linearized viscoelastic flows in a general two-dimensional domain with certain parameters small and the time variable large.

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A Window On The Fifth Dimension, Frank A. Farris Nov 2008

A Window On The Fifth Dimension, Frank A. Farris

Mathematics and Computer Science

Is there enough mathematics in your home? What visual aids do you keep on hand for that inevitable moment when guests want to know why you spend your life on mathematics? Feeling a lack in this area, I commissioned glass artist Hans Schepker to produce a window - from the fifth dimension? - based on an image that came up in my research. It turned out splendidly, and you can see it on the cover of this issue of MAA FOCUS.

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Asymptotic Behavior Of Linearized Viscoelastic Flow Problem, Yinnian He, Yi Li Nov 2008

Asymptotic Behavior Of Linearized Viscoelastic Flow Problem, Yinnian He, Yi Li

Mathematics and Statistics Faculty Publications

In this article, we provide some asymptotic behaviors of linearized viscoelastic flows in a general two-dimensional domain with certain parameters small and the time variable large.

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Mathematics In The Mountains: The Park City Mathematics Institute, Andrew J. Bernoff Nov 2008

Mathematics In The Mountains: The Park City Mathematics Institute, Andrew J. Bernoff

All HMC Faculty Publications and Research

It's noon. A Fields medalist, master high school teachers from the US and abroad, aspiring undergraduate and graduate students, gifted expositors of mathematics, and mathematical artists gather at tables under a tent. Lunch and so much more is served at these meetings of the minds.

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Genetic Markers Of Igg Influence The Outcome Of Infection With Hepatitis C Virus, Janardan P. Pandey, Aryan M. Namboodiri, Yuqun Luo, Yuping Wu, Robert C. Elston, David L. Thomas, Hugo R. Rosen, James J. Goedert Nov 2008

Genetic Markers Of Igg Influence The Outcome Of Infection With Hepatitis C Virus, Janardan P. Pandey, Aryan M. Namboodiri, Yuqun Luo, Yuping Wu, Robert C. Elston, David L. Thomas, Hugo R. Rosen, James J. Goedert

Mathematics and Statistics Faculty Publications

We examined the role that immunoglobulin GM and KM allotypes—genetic markers of γ and κ chains, respectively—play in the outcome of hepatitis C virus (HCV) infection in white Americans. A total of 119 persons who had cleared HCV and 111 with persistent HCV infection were genotyped for the presence of several GM and KM determinants. Persistent HCV infection was more than three times as likely (odds ratio, 3.50; P = .01) in subjects who were carriers of the GM3 allele than in those who were noncarriers. These results show that particular GM alleles may be important determinants of the outcome …

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Ubi-App: A Ubiquitous Application For Universal Access From Handheld Devices, Shameem Ahmed, Moushumi Sharmin, Sheikh Iqbal Ahamed Nov 2008

Ubi-App: A Ubiquitous Application For Universal Access From Handheld Devices, Shameem Ahmed, Moushumi Sharmin, Sheikh Iqbal Ahamed

Mathematics, Statistics and Computer Science Faculty Research and Publications

Universal access from a handheld device (such as a PDA, cell phone) at any time or anywhere is now a reality. Ubicomp Assistant (UA) (Sharmin et al. in Proceedings of the 21st annual ACM symposium on applied computing (ACM SAC 2006), Dijon, France, pp 1013–1017, 2006) is an integral service of MARKS (Sharmin et al. in Proceedings of the third international conference on information technology: new generations (ITNG 2006), Las Vegas, Nevada, USA, pp 306–313, 2006). It is a middleware developed for handheld devices, and has been designed to accommodate different types of users (e.g., education, healthcare, marketing, or business). …

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Queen's Domination Using Border Squares And (A,B)-Restricted Domination, Anne Sinko, Peter J. Slater Oct 2008

Queen's Domination Using Border Squares And (A,B)-Restricted Domination, Anne Sinko, Peter J. Slater

Mathematics Faculty Publications

In this paper we introduce a variant on the long studied, highly entertaining, and very difficult problem of determining the domination number of the queen's chessboard graph, that is, determining how few queens are needed to protect all of the squares of a k by k chessboard. Motivated by the problem of minimum redundance domination, we consider the problem of determining how few queens restricted to squares on the border can be used to protect the entire chessboard. We give exact values of "border-queens" required for the k by k chessboard when 1≤k≤13. For the general case, we …

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Contributions To Random Energy Models., Nabin Kumar Jana Dr. Oct 2008

Contributions To Random Energy Models., Nabin Kumar Jana Dr.

Doctoral Theses

In this introductory chapter, we begin with a brief description of spin glasses in section 1. We are not physicists. The purpose of this section is to trace the history of the models. Section 2 gives a brief summary of the thesis and section 3 recalls certain known facts which will be used later in the thesis.Origin of the problem The models considered in this thesis have their origin in spin glass theory. Roughly, spin glass is a glassy state in a spin system or a disordered material exhibiting high magnetic frustration. The origin of this behavior can be either …

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On Injectivity Of Quasiregular Mappings, Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen Oct 2008

On Injectivity Of Quasiregular Mappings, Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen

Mathematics - All Scholarship

We give sufficient conditions for a planar quasiregular mapping to be injective in terms of the range of the differential matrix.

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On The Colored Jones Polynomial, Sutured Floer Homology, And Knot Floer Homology, J. Elisenda Grigsby, Stephan Wehrli Oct 2008

On The Colored Jones Polynomial, Sutured Floer Homology, And Knot Floer Homology, J. Elisenda Grigsby, Stephan Wehrli

Mathematics - All Scholarship

Let K in S3 be a knot, and let K denote the preimage of K inside its double branched cover, Sigma(S3, K). We prove, for each integer n > 1, the existence of a spectral sequence from Khovanov's categorification of the reduced n-colored Jones polynomial of K (mirror of K) and whose Einfinity term is the knot Floer homology of (Sigma(S3,K),K) (when n odd) and to (S3, K # K) (when n even). A corollary of our result is that Khovanov's categorification of the reduced n-colored Jones polynomial detects the unknot whenever n …

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Siegel’S Lemma Outside Of A Union Of Varieties, Lenny Fukshansky Oct 2008

Siegel’S Lemma Outside Of A Union Of Varieties, Lenny Fukshansky

CMC Faculty Publications and Research

Lecture given at the AMS Special Session on Number Theory, October 2008.

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Contributions To Khovanov Homology, Stephan M. Wehrli Oct 2008

Contributions To Khovanov Homology, Stephan M. Wehrli

Mathematics - All Scholarship

Khovanov homology ist a new link invariant, discovered by M. Khovanov, and used by J. Rasmussen to give a combinatorial proof of the Milnor conjecture. In this thesis, we give examples of mutant links with different Khovanov homology. We prove that Khovanov's chain complex retracts to a subcomplex, whose generators are related to spanning trees of the Tait graph, and we exploit this result to investigate the structure of Khovanov homology for alternating knots. Further, we extend Rasmussen's invariant to links. Finally, we generalize Khovanov's categorifications of the colored Jones polynomial, and study conditions under which our categorifications are functorial …

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Optimization Of Delay-Differential Inclusions Of Infinite Dimensions, Boris S. Mordukhovich, Dong Wang, Lianwen Wang Oct 2008

Optimization Of Delay-Differential Inclusions Of Infinite Dimensions, Boris S. Mordukhovich, Dong Wang, Lianwen Wang

Mathematics Research Reports

No abstract provided.

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2008 (Fall), University Of Dayton. Department Of Mathematics Oct 2008

2008 (Fall), University Of Dayton. Department Of Mathematics

Colloquia

Abstracts of the talks given at the 2008 Fall Colloquium.

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Math/Compsci Newsletter, Fall 2008, Department Of Mathematics And Computer Science, Bridgewater State College Oct 2008

Math/Compsci Newsletter, Fall 2008, Department Of Mathematics And Computer Science, Bridgewater State College

Department of Mathematics Newsletter

No abstract provided.

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Tiling Proofs Of Recent Sum Identities Involving Pell Numbers, Arthur T. Benjamin, Sean S. Plott '08, James A. Sellers Oct 2008

Tiling Proofs Of Recent Sum Identities Involving Pell Numbers, Arthur T. Benjamin, Sean S. Plott '08, James A. Sellers

All HMC Faculty Publications and Research

In a recent note, Santana and Diaz-Barrero proved a number of sum identities involving the well-known Pell numbers. Their proofs relied heavily on the Binet formula for the Pell numbers. Our goal in this note is to reconsider these identities from a purely combinatorial viewpoint. We provide bijective proofs for each of the results by interpreting the Pell numbers as enumerators of certain types of tilings. In turn, our proofs provide helpful insight for straightforward generalizations of a number of the identities.

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Permutation Representations On Schubert Varieties, Julianna S. Tymoczko Oct 2008

Permutation Representations On Schubert Varieties, Julianna S. Tymoczko

Mathematics Sciences: Faculty Publications

This paper defines and studies permutation representations on the equivariant cohomology of Schubert varieties, as representations both over ℂ and over ℂ[t1, t2, . . . , tn]. We show these group actions are the same as an action of simple transpositions studied geometrically by M. Brion, and give topological meaning to the divided difference operators of Berstein-Gelfand-Gelfand, Demazure, Kostant-Kumar, and others. We analyze these representations using the combinatorial approach to equivariant cohomology introduced by Goresky-Kottwitz-MacPherson. We find that each permutation representation on equivariant cohomology produces a representation on ordinary cohomology that is trivial, though the equivariant representation is not.

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Supplementary Text To Accompany “Cell Groups Reveal Structure Of Stimulus Space”, Carina Curto, Vladimir Itskov Oct 2008

Supplementary Text To Accompany “Cell Groups Reveal Structure Of Stimulus Space”, Carina Curto, Vladimir Itskov

Department of Mathematics: Faculty Publications

Here we present a brief exposition of some material from algebraic topology that we use in our methods. We include it for completeness, as it may not be familiar for many readers. In particular, we define simplicial complexes, simplicial homology groups, and state the theorem cited in the Results section. See [Bott and Tu, 1982, Ewald, 1996, Hatcher, 2002] for more details.

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Cell Groups Reveal Structure Of Stimulus Space, Carina Curto, Vladimir Itskov Oct 2008

Cell Groups Reveal Structure Of Stimulus Space, Carina Curto, Vladimir Itskov

Department of Mathematics: Faculty Publications

An important task of the brain is to represent the outside world. It is unclear how the brain may do this, however, as it can only rely on neural responses and has no independent access to external stimuli in order to ‘‘decode’’ what those responses mean. We investigate what can be learned about a space of stimuli using only the action potentials (spikes) of cells with stereotyped—but unknown—receptive fields. Using hippocampal place cells as a model system, we show that one can (1) extract global features of the environment and (2) construct an accurate representation of space, up to an …

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The Matrices R And G Of Matrix Analytic Methods And The Time-Inhomogeneous Periodic Quasi-Birth-And-Death Process, Barbara H. Margolius Oct 2008

The Matrices R And G Of Matrix Analytic Methods And The Time-Inhomogeneous Periodic Quasi-Birth-And-Death Process, Barbara H. Margolius

Mathematics and Statistics Faculty Publications

We solve for the asymptotic periodic distribution of the continuous time quasi-birth-and-death process with time-varying periodic rates in terms of R^ and G^ matrix functions which are analogues of the R and G matrices of matrix analytic methods. We evaluate these QBDs numerically by solving for R^ numerically.

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A Hyperbolic Two-Step Model Based Finite Difference Method For Studying Thermal Deformation In Three-Dimensional Micro Spheres Exposed To Ultrashort-Pulsed Lasers, Pan Wang Oct 2008

A Hyperbolic Two-Step Model Based Finite Difference Method For Studying Thermal Deformation In Three-Dimensional Micro Spheres Exposed To Ultrashort-Pulsed Lasers, Pan Wang

Doctoral Dissertations

Ultrashort-pulsed lasers with pulse durations of the order of sub-picoseconds to femtoseconds possess the capabilities in limiting the undesirable spread of the thermal process zone in a heated sample. Because of this, ultrashort-pulsed lasers have been attracting worldwide interest in science and engineering. The success of ultrashort-pulsed lasers in real application relies on: (1) well characterized pulse width, intensity and experimental techniques; (2) reliable microscale heat transfer models; and (3) prevention of thermal damage. Laser damage induced by ultrashort-pulsed lasers occurs after the heating pulse is over, since the pulse duration time is extremely short and the heat flux is …

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Biomimetic Subwavelength Antireflective Gratings On Gaas, Chih-Hung Sun, Brian J. Ho, Bin Jiang, Peng Jiang Oct 2008

Biomimetic Subwavelength Antireflective Gratings On Gaas, Chih-Hung Sun, Brian J. Ho, Bin Jiang, Peng Jiang

Mathematics and Statistics Faculty Publications and Presentations

We have developed a simple and scalable bottom-up approach for fabricating moth-eye antireflective coatings on GaAs substrates. Monolayer, non-close-packed silica colloidal crystals are created on crystalline GaAs wafers by a spin-coating-based single-layer reduction technique. These colloidal monolayers can be used as etching masks during a BCl_3 dry-etch process to generate subwavelength-structured antireflective gratings directly on GaAs substrates. The gratings exhibit excellent broadband antireflective properties, and the specular reflection matches with the theoretical prediction using a rigorous coupled-wave analysis model. These bioinspired antireflection coatings have important technological applications ranging from efficient solar cells to IR detectors

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Using Spreadsheets To Discover Meaning For Parameters In Nonlinear Models, Kris H. Green Oct 2008

Using Spreadsheets To Discover Meaning For Parameters In Nonlinear Models, Kris H. Green

Mathematical and Computing Sciences Faculty/Staff Publications

Using spreadsheets one can develop an exploratory environment where mathematics students can develop their own understanding of the relationship between the parameters of commonly encountered families of functions (linear, logarithmic, exponential and power) and a natural interpretation of “rate of change” for those functions. The key to this understanding involves expanding the concept of rate of change to include percent changes. Through the use of the spreadsheet model, students can explore and easily determine which type of change is most natural for a given family of functions. This, in turn, provides a mechanism for interpreting the parameters of the function …

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Factoring Families Of Positive Knots On Lorenz-Like Templates, Michael C. Sullivan Oct 2008

Factoring Families Of Positive Knots On Lorenz-Like Templates, Michael C. Sullivan

Articles and Preprints

We show that for m and n positive, composite closed orbits realized on the Lorenz-like template L(m, n) have two prime factors, each a torus knot; and that composite closed orbits on L(−1,−1) have either two for three prime factors, two of which are torus knots.

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Applications Of Combinatorial Designs In Key Pre-Distribution In Sensor Networks., Dibyendu Chakrabarti Dr. Sep 2008

Applications Of Combinatorial Designs In Key Pre-Distribution In Sensor Networks., Dibyendu Chakrabarti Dr.

Doctoral Theses

Key pre-distribution is an important area of research in Distributed Sensor Networks (DSN). Some improved techniques over the existing schemes (employing combinatorial designs) have been proposed in this thesis and detailed mathematical analysis of the schemes has been presented. At first, combinatorial design followed by randomized merging strategy is applied to key pre-distribution in sensor nodes. Our main target is to get more than one pair of common keys between any pair of nodes to provide a robust network in terms of security under adversarial conditions where some nodes may get compromised. A transversal design is used to construct a …

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