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2013

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Articles 481 - 510 of 1053

Full-Text Articles in Mathematics

Diminished Antioxidant Activity Of High-Density Lipoprotein–Associated Proteins In Chronic Kidney Disease, David J. Kennedy, W.H. Wilson Tang, Yiying Fan, Yuping Wu, Shirley Mann, Michael Pepoy, Stanley L. Hazen Apr 2013

Diminished Antioxidant Activity Of High-Density Lipoprotein–Associated Proteins In Chronic Kidney Disease, David J. Kennedy, W.H. Wilson Tang, Yiying Fan, Yuping Wu, Shirley Mann, Michael Pepoy, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Background:Decreased serum arylesterase activity, catalyzed by the high-density lipoprotein–associated paraoxonase (PON)-1, is associated with increased oxidant stress and atherosclerosis risk. We sought to determine the prognostic value of serum PON-1 activity, as monitored by PON or arylesterase activities, in subjects with chronic kidney disease (CKD), particularly in relation to established cardiac biomarkers.Methods and Results: Serum arylesterase and PON activities were measured in sequential subjects with CKD (n=630; estimated glomerular filtration rate [eGFR] <60 mL/min per 1.73 m2) and an age- and sex-matched control group of non-CKD subjects (n=315) presenting for cardiac evaluations and prospectively followed for incident (3-year) major adverse cardiac events (composite of death, nonfatal myocardial infarction, and stroke). Serum arylesterase activity in CKD subjects was lower compared with that in non-CKD control subjects [median (interquartile range) 94 (77 to 112) versus 103 (85 to 121) μmol(L·min) per mL, P<0.001]; similarly, PON activity in CKD subjects was lower compared with that in non-CKD control subjects [median (interquartile range) 474 (275 to 936) versus 586 (301 to 1118) nmol(L·min) per mL, P<0.001]. Lower serum arylesterase (hazard ratio 1.8, 95% CI 1.26 to 2.57, P<0.01) was a predictor of poorer outcomes. After adjusting for traditional risk factors and medication use, lower serum arylesterase (hazard ratio 1.55, 95% CI 1.08 to 2.23, P<0.05) still conferred an increased risk of major adverse cardiac events at 3 years. Conclusions: In patients with CKD, decreased serum arylesterase activity, a measure of diminished antioxidant properties of PON-1, predicts higher risk of incident long-term adverse cardiovascular events (heart attack, stroke, or death) in multivariable models adjusting for established clinical and biochemical risk factors.

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Study Of Spatiotemporal Signatures Between Objects To Improve Video Segmentation In Complex Environments, Adam Robert Reckley Apr 2013

Study Of Spatiotemporal Signatures Between Objects To Improve Video Segmentation In Complex Environments, Adam Robert Reckley

Electrical & Computer Engineering Theses & Dissertations

Background subtraction is often considered to be a required stage of any video surveillance system being used to detect objects in a single frame and/or track objects across multiple frames in a video sequence. Most current state-of-the-art techniques for object detection and tracking utilize some form of background subtraction that involves developing a model of the background at a pixel, region or frame level and designating any elements that deviate from the background model as foreground. Most existing approaches are capable of segmenting a number of distinct components, but are unable to distinguish between the desired object of interest and …

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Variational Methods On Elastic Curves, Daniel D. Rocker Apr 2013

Variational Methods On Elastic Curves, Daniel D. Rocker

College of Graduate Studies: Theses & Dissertations

In this thesis we investigate elastic curves. These are curves with minimal bending energy as measured by the total squared curvature functional. We show that these can be computed by evolving curves in the direction of the negative gradient in certain Hilbert space settings. By discretizing the curves and using numerical integration, we compute approximate minimizers and display using computer graphics. We propose a conjecture based on the rotation number of a curve that predicts the critical point curves that minimize bending energy.

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Approximate Similarity Reduction, Rui Zhang Apr 2013

Approximate Similarity Reduction, Rui Zhang

College of Graduate Studies: Theses & Dissertations

The nonlinear K (n;1) equation with damping is investigated via the approximate homotopy symmetry method and approximate homotopy direct method. The approximate homotopy symmetry and homotopy similarity reduction equations of different orders are derived and the corresponding homotopy series reduction solutionsare obtained. As a result, the formal coincidence for both methods is displayed.

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The String Landscape: On Formulas For Counting Vacua, Tamar Friedmann, Richard P. Stanley Apr 2013

The String Landscape: On Formulas For Counting Vacua, Tamar Friedmann, Richard P. Stanley

Mathematics Sciences: Faculty Publications

We derive formulas for counting certain classes of vacua in the string/M theory landscape. We do so in the context of the moduli space of M-theory compactifications on singular manifolds with G2 holonomy. Particularly, we count the numbers of gauge theories with different gauge groups but equal numbers of U (1) factors which are dual to each other. The vacua correspond to various symmetry breaking patterns of grand unified theories. Counting these dual vacua is equivalent to counting the number of conjugacy classes of elements of finite order inside Lie groups. We also point out certain cases where the …

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Difference Sets In Non-Abelian Groups Of Order 256, Taylor Applebaum Apr 2013

Difference Sets In Non-Abelian Groups Of Order 256, Taylor Applebaum

Honors Theses

This paper considers the problem of determining which of the 56092 groups of order 256 contain (256; 120; 56; 64) difference sets. John Dillon at the National Security Agency communicated 724 groups which were still open as of August 2012. In this paper, we present a construction method for groups containing a normal subgroup isomorphic to Z4 Z4 Z2 . This construction method was able to produce difference sets in 643 of the 649 unsolved groups with the correct normal subgroup. These constructions elimated approximately 90% of the open cases, leaving 81 remaining unsolved groups.

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Power Distribution In The European Union, Dayton Steele Apr 2013

Power Distribution In The European Union, Dayton Steele

Honors Theses

The Treaty of Lisbon, the latest treaty governing law-making in the European Union (EU), was ratified in 2009 and goes fully into effect in 2014. This treaty, with its change to voting procedures in the Council of Ministers, claims to make decision-making in the EU more democratic and more efficient. Since the EU serves as an economic and political entity, we will assess these claims by comparing each member state's GDP and population to its power as modeled using the concept of a power index from the game theory literature. We will utilize the normalized Banzhaf index, the Shapley-Shubik index, …

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A Data Generating Review That Bops, Twists And Pulls At Misconceptions, Kimberly Gardner Apr 2013

A Data Generating Review That Bops, Twists And Pulls At Misconceptions, Kimberly Gardner

Faculty Articles

Statistics is an integral part of the K-12 mathematics curriculum (age 5-18). Naturally, students construct misconceptions of what they learn. This article discusses The Bop It© Challenge, a review activity assesses student understanding and reveals their misundertandings of statistical concepts.

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Statistical Properties Of The Mc-Dagum And Related Distributions, Sasith Rajasooriya Apr 2013

Statistical Properties Of The Mc-Dagum And Related Distributions, Sasith Rajasooriya

College of Graduate Studies: Theses & Dissertations

In this thesis, we present a new class of distributions called Mc-Dagum distribution. This class of distributions contains several distributions such as beta-Dagum, beta-Burr III, beta-Fisk and Dagum distributions as special cases. The hazard function, reverse hazard function, moments and mean residual life function are obtained. Inequality measures, entropy and Fisher information are presented. Maximum likelihood estimates of the model parameters are given.

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Novel Algorithms And Instrumentation For Vibrational Spectroscopic Methods Of Analysis, Mohamed F. Abdelkader Apr 2013

Novel Algorithms And Instrumentation For Vibrational Spectroscopic Methods Of Analysis, Mohamed F. Abdelkader

Chemistry & Biochemistry Theses & Dissertations

Raman spectroscopy is a form of vibrational spectroscopy that has been increasingly applied to qualitative analysis of chemicals, explosives, pharmaceuticals, and fuels due to its non-invasive and non-destructive nature; its ease of sampling; and its high molecular specificity. These characteristics of Raman spectroscopy also facilitate its use for both in-line and at-line analysis. The principle limitation of Raman spectroscopy is optical interference arising from both analyte and non-analyte fluorescence. In this dissertation, a solution to this problem is presented in the form of a novel spectrometer design which operates in a sequentially shifted excitation mode to eliminate fluorescence backgrounds, fixed …

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Enumeration Of (16,4,16,4) Relative Difference Sets, David C. Clark, Vladimir Tonchev Mar 2013

Enumeration Of (16,4,16,4) Relative Difference Sets, David C. Clark, Vladimir Tonchev

Department of Mathematical Sciences Publications

A complete enumeration of relative difference sets (RDS) with parameters (16, 4, 16, 4) in a group of order 64 with a normal subgroup N of order 4 is given. If N = Z4 , three of the 11 abelian groups of order 64, and 23 of the 256 nonabelian groups of order 64 contain (16, 4, 16, 4) RDSs. If N = Z2 × Z2 , nine of the abelian groups and 194 of the non-abelian groups of order 64 contain (16, 4, 16, 4) RDSs.

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Some New Applications Of P-P Plots, Isha Dewan, Subhash C. Kochar Mar 2013

Some New Applications Of P-P Plots, Isha Dewan, Subhash C. Kochar

Mathematics and Statistics Faculty Publications and Presentations

The P-P plot is a powerful graphical tool to compare stochastically the magnitudes of two random variables. In this note, we introduce a new partial order, called P?P order based on P-P plots. For a pair of random variables (X 1, Y1) and (X 2, Y 2) one can see the relative precedence of Y 2 over X 2 versus that of Y 1 over X 1 using P-P order. We show that several seemingly very technical and difficult concepts like convex transform order and super-additive ordering can be easily explained with the …

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Oscillation Of Third-Order Nonlinear Delay Differential Equations, Ravi P. Agarwal, Martin Bohner, Tongxing Li, Chenghui Zhang Mar 2013

Oscillation Of Third-Order Nonlinear Delay Differential Equations, Ravi P. Agarwal, Martin Bohner, Tongxing Li, Chenghui Zhang

Mathematics and Statistics Faculty Research & Creative Works

In this paper, we study the oscillatory behavior of a class of third-order nonlinear delay differential equations (a(t)(b(t)y′(t)) ′) ′+q(t)yγ(τ(t)) =0. Some new oscillation criteria are presented by transforming this equation to the first order delayed and advanced differential equations. Employing suitable comparison theorems, we establish new results on oscillation of the studied equation. Assumptions in our theorems are less restrictive; these criteria improve those in the recent paper [Appl. Math. Comput., 202 (2008), 102-112] and related contributions to the subject. Examples are provided to illustrate new results.

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Information-Based Physics: An Intelligent Embedded Agent's Guide To The Universe, Kevin H. Knuth Mar 2013

Information-Based Physics: An Intelligent Embedded Agent's Guide To The Universe, Kevin H. Knuth

Physics Faculty Scholarship

In this talk, I propose an approach to understanding the foundations of physics by considering the optimal inferences an intelligent agent can make about the universe in which he or she is embedded. Information acts to constrain an agent’s beliefs. However, at a fundamental level, any information is obtained from interactions where something influences something else. Given this, the laws of physics must be constrained by both the nature of such influences and the rules by which we can make inferences based on information about these influences. I will review the recent progress we have made in this direction. This …

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Variation Of Instructor-Student Interactions In An Introductory Interactive Physics Course, Emily West, Cassandra Paul, David Webb, Wendell Potter Mar 2013

Variation Of Instructor-Student Interactions In An Introductory Interactive Physics Course, Emily West, Cassandra Paul, David Webb, Wendell Potter

Faculty Publications

The physics instruction at UC Davis for life science majors takes place in a long-standing reformed large-enrollment physics course in which the discussion or laboratory instructors (primarily graduate student teaching assistants) implement the interactive-engagement (IE) elements of the course. Because so many different instructors participate in disseminating the IE course elements, we find it essential to the instructors’ professional development to observe and document the student-instructor interactions within the classroom. Out of this effort, we have developed a computerized real-time instructor observation tool (RIOT) to take data of student-instructor interactions. We use the RIOT to observe 29 different instructors for …

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Enhanced Surveillance On Food-Borne Disease Outbreaks: Dynamics Of Cross-Contamination In Biocidal Wash Procedure, Daniel Munther, Jianhong Wu Mar 2013

Enhanced Surveillance On Food-Borne Disease Outbreaks: Dynamics Of Cross-Contamination In Biocidal Wash Procedure, Daniel Munther, Jianhong Wu

Mathematics and Statistics Faculty Publications

Understanding the geographic and temporal spread of food-borne diseases associated with fresh produce is crucial for informing adequate surveillance and control. As a first step towards this goal, we develop and analyze a novel three stage model at the processing/sanitization juncture in the fresh produce supply chain. The key feature of our model is its ability to describe the dynamics of cross-contamination during commercial wash procedures. In general, we quantify the degree of cross-contamination in terms of model parameters. Applying these results in the case of Escherichia coli O157:H7 contamination of fresh-cut romaine lettuce, we identify the mean wash time …

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Investigation Into The Ratio Of System Operations And Support Costs To Life-Cycle Costs For Department Of Defense Weapon Systems, Gary L. Jones Mar 2013

Investigation Into The Ratio Of System Operations And Support Costs To Life-Cycle Costs For Department Of Defense Weapon Systems, Gary L. Jones

Theses and Dissertations

As the arsenal of weapons managed by the Department of Defense (DoD) ages, the country's leadership is forced to make decisions regarding what to do with current and projected funding to maintain military defensive and offensive capabilities. The acquisition community at many levels has stated that O&S costs are about 70 percent of the total life-cycle costs of the average system, the other 30 percent being spent in the acquisition phase. This golden ratio does not appear to come from empirical evidence. There has been little research into the actual ratio of O&S-to-acquisition costs. This research found a significant departure …

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Determining Optimal Machine Replacement Events With Periodic Inspection Intervals, Theodore C. Shiveley Mar 2013

Determining Optimal Machine Replacement Events With Periodic Inspection Intervals, Theodore C. Shiveley

Theses and Dissertations

This research will examine the optimal maintenance and replacement policies for a generic machine with periodic inspection intervals. The considered reliability models consist of a single machine that can fail during operation or else may be found to be inoperative during regularly-scheduled maintenance inspections. A distinction will be made between spontaneously-occurring failures during operation and those that are discovered during inspections. Since the elapsed time between inspections is constant, the resulting stochastic reliability process becomes non-Markovian, and thus a Semi-Markov Decision Process (SMDP) framework must be employed in order to determine the cost-optimal stationary policy consisting of repair and replace …

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Aliquot Cycles For Elliptic Curves With Complex Multiplication, Thomas Morrell Mar 2013

Aliquot Cycles For Elliptic Curves With Complex Multiplication, Thomas Morrell

Undergraduate Theses—Unrestricted

We review the history of elliptic curves and show that it is possible to form a group law using the points on an elliptic curve over some field L. We review various methods for computing the order of this group when L is finite, including the complex multiplication method. We then define and examine the properties of elliptic pairs, lists, and cycles, which are related to the notions of amicable pairs and aliquot cycles for elliptic curves, defined by Silverman and Stange. We then use the properties of elliptic pairs to prove that aliquot cycles of length greater than …

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The K-Dominating Graph, Ruth Haas, Karen Seyffarth Mar 2013

The K-Dominating Graph, Ruth Haas, Karen Seyffarth

Mathematics Sciences: Faculty Publications

Abstract. Given a graph G, the k-dominating graph of G, Dk(G), is defined to be the graph whose vertices correspond to the dominating sets of G that have cardinality at most k. Two vertices in Dk(G) are adjacent if and only if the corresponding dominating sets of G differ by either adding or deleting a single vertex. The graph Dk(G) aids in studying the reconfiguration problem for dominating sets. In particular, one dominating set can be reconfigured to another by a sequence of single vertex additions and deletions, such that the intermediate set of …

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Waring Decompositions Of Monomials, Weronika Buczyńska, Jarosław Buczyński, Zach Teitler Mar 2013

Waring Decompositions Of Monomials, Weronika Buczyńska, Jarosław Buczyński, Zach Teitler

Mathematics Faculty Publications and Presentations

A Waring decomposition of a polynomial is an expression of the polynomial as a sum of powers of linear forms, where the number of summands is minimal possible. We prove that any Waring decomposition of a monomial is obtained from a complete intersection ideal, determine the dimension of the set of Waring decompositions, and give the conditions under which the Waring decomposition is unique up to scaling the variables.

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Propeller, Joel Kahn Mar 2013

Propeller, Joel Kahn

The Transdisciplinary STEAM+ Journal

This image is based on several different algorithms interconnected within a single program in the language BASIC-256. The fundamental structure involves a tightly wound spiral working outwards from the center of the image. As the spiral is drawn, different values of red, green and blue are modified through separate but related processes, producing the changing appearance. Algebra, trigonometry, geometry, and analytic geometry are all utilized in overlapping ways within the program. As with many works of algorithmic art, small changes in the program can produce dramatic alterations of the visual output, which makes lots of variations possible.

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Stable Image Reconstruction Using Total Variation Minimization, Deanna Needell, Rachel Ward Mar 2013

Stable Image Reconstruction Using Total Variation Minimization, Deanna Needell, Rachel Ward

CMC Faculty Publications and Research

This article presents near-optimal guarantees for stable and robust image recovery from undersampled noisy measurements using total variation minimization. In particular, we show that from O(s log(N)) nonadaptive linear measurements, an image can be reconstructed to within the best s-term approximation of its gradient up to a logarithmic factor, and this factor can be removed by taking slightly more measurements. Along the way, we prove a strengthened Sobolev inequality for functions lying in the null space of suitably incoherent matrices.

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Inverse Spectral Problems For Graphs, Dr. Wayne Barrett Mar 2013

Inverse Spectral Problems For Graphs, Dr. Wayne Barrett

Journal of Undergraduate Research

This MEG grant made it possible to support several student research activ- ities from Spring 2009 through Winter 2010.

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Fractional Calculus And Smallest Eigenvalues, Jeffrey T. Neugebauer Mar 2013

Fractional Calculus And Smallest Eigenvalues, Jeffrey T. Neugebauer

Mathematics Colloquium Series

This talk will introduce the subject of fractional calculus, which involves taking integrals and derivatives of arbitrary order. Neugebauer will show how the definitions of fractional derivatives and fractional integrals are natural extensions of the definitions of the derivative and the integral. In addition to showing some examples, Neugebauer will explore ongoing research on the comparison of smallest eigenvalues of a fractional-boundary-value problem with conjugate boundary conditions.

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Character Tables Of Metacyclic Groups, Dane Christian Skabelund Mar 2013

Character Tables Of Metacyclic Groups, Dane Christian Skabelund

Theses and Dissertations

We show that any two split metacyclic groups with the same character tables are isomorphic. We then use this to show that among metacyclic groups that are either 2-groups or are of odd order divisible by at most two primes, that the dihedral and generalized quaternion groups of order 2^n, n = 3, are the only pairs that have the same character tables.

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Euler’S Algebraic Creativity And Undergraduate Math, Christopher D. Goff Mar 2013

Euler’S Algebraic Creativity And Undergraduate Math, Christopher D. Goff

College of the Pacific Faculty Presentations

This talk will describe the author’s work translating a paper of Euler on number theory, and how researching the history of this paper led back to Lagrange, Fermat, and ultimately to a geometry problem of Diophantus. We will investigate Euler’s algebraic creativity and Lagrange’s explanation of his own method, inspired by Fermat. Moreover, we will demonstrate one way in which this paper of Euler’s has been used as part of a project in an undergraduate history of mathematics course. We will even investigate the continuation of Euler’s work.

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Developing A Stem Teacher Recruitment Pipeline, Kimberly Shaw, Cindy Ticknor, Tim Howard Mar 2013

Developing A Stem Teacher Recruitment Pipeline, Kimberly Shaw, Cindy Ticknor, Tim Howard

Interdisciplinary STEM Teaching & Learning Conference (2012-2019) (Archived)

The Columbus Region Academy of Future Teachers of STEM (CRAFT-STEM), a Phase I Robert Noyce Teacher Scholarship Program, combines internships and scholarships, an exciting summer STEM Honors Camp, a new Teaching Connections Seminar, and an impressive array of existing resources to recruit, prepare, and graduate an increasing number of STEM teachers committed to serving high need high schools.

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Integrating Manipulatives To Improve Fraction Concepts, Rachel Dunn Mar 2013

Integrating Manipulatives To Improve Fraction Concepts, Rachel Dunn

Interdisciplinary STEM Teaching & Learning Conference (2012-2019) (Archived)

The aim of this session is to demonstrate the tools used to help reinforce and recreate students’ conceptual knowledge of fractions, specifically targeting the unit of reference. These manipulatives will provide teachers with instructional support for Common Core Standards, which emphasize critical thinking skills and various representations of knowledge, specifically with fractions. Participants will become actively engaged in learning about these tools, including jumping on a number line floor mat, working with circular fraction pieces and placing fractions on a number line rope. By representing knowledge through circular and linear methods, students will use critical thinking skills and support will …

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Integrating Manipulatives To Improve Fraction Concepts, Rachel Dunn Mar 2013

Integrating Manipulatives To Improve Fraction Concepts, Rachel Dunn

Interdisciplinary STEM Teaching & Learning Conference (2012-2019) (Archived)

Many students are overwhelmed by mathematics because the language is too difficult, the teaching strategies are insufficient or they have lost motivation. With a recent emphasis on meeting the Common Core expectations, using manipulatives to eliminate misconceptions in the mathematical classroom has become even more prevalent. I explored the misconceptions that many students struggle with and provided possible methods of eliminating them at all levels for learning. During this investigation, I studied the effect of manipulatives on students’ understanding of fraction concepts and the students’ conceptions of the unit of reference when working with fraction word problems. I learned that …

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