Mathematics Commons^™

Unraveling The Dose-Response Puzzle Of L. Monocytogenes: A Mechanistic Approach, S. M.Ashrafur Rahman, Daniel Munther, Aamir Fazil, Ben Smith, Jianhong Wu

Mathematics and Statistics Faculty Publications

Food-borne disease outbreaks caused by Listeria monocytogenes continue to impose heavy burdens on public health in North America and globally. To explore the threat L. monocytogenes presents to the elderly, pregnant woman and immuno-compromised individuals, many studies have focused on in-host infection mechanisms and risk evaluation in terms of dose-response outcomes. However, the connection of these two foci has received little attention, leaving risk prediction with an insufficient mechanistic basis. Consequently, there is a critical need to quantifiably link in-host infection pathways with the dose-response paradigm. To better understand these relationships, we propose a new mathematical model to describe the …

The Choice Of Prior Distribution For A Covariance Matrix In Multivariate Meta-Analysis: A Simulation Study, Sandra M. Hurtado Rua, Madhu Mazumdar, Robert L. Strawderman

Mathematics and Statistics Faculty Publications

Bayesian meta-analysis is an increasingly important component of clinical research, with multivariate meta-analysis a promising tool for studies with multiple endpoints. Model assumptions, including the choice of priors, are crucial aspects of multivariate Bayesian meta-analysis (MBMA) models. In a given model, two different prior distributions can lead to different inferences about a particular parameter. A simulation study was performed in which the impact of families of prior distributions for the covariance matrix of a multivariate normal random effects MBMA model was analyzed. Inferences about effect sizes were not particularly sensitive to prior choice, but the related covariance estimates were. A …

Closed Range Composition Operators On Hilbert Function Spaces, Pratibha Ghatage, Maria Tjani

Mathematics and Statistics Faculty Publications

We show that a Carleson measure satisfies the reverse Carleson condition if and only if its Berezin symbol is bounded below on the unit disk D. We provide new necessary and sufficient conditions for the composition operator to have closed range on the Bergman space. The pull-back measure of area measure on D plays an important role. We also give a new proof in the case of the Hardy space and conjecture a condition in the case of the Dirichlet space.

The Heart Failure Overweight/Obesity Survival Paradox : The Missing Sex Link, Amanda R. Vest, Yuping Wu, Roy Hachamovitch, James B. Young, Leslie Cho

Mathematics and Statistics Faculty Publications

Objectives: This study sought to determine whether body mass index (BMI) has a differential impact on survival for females versus males with advanced systolic heart failure (HF). Background: Females have a survival advantage in HF, the mechanisms of which are unclear. There is also a proposed “obesity survival paradox” in which excess adiposity promotes HF survival. Methods: We reviewed 3,811 patients with left ventricular ejection fraction ≤40% who had undergone cardiopulmonary exercise testing between 1995 and 2011. The endpoint was all-cause mortality. Multivariable analysis was performed using a Cox proportional hazards model. Because of the nonlinearity of BMI, a restricted …

A Mathematical Model For Pathogen Cross-Contamination Dynamics During Produce Wash, Daniel Munther, Yaguang Luo, Jianhong Wu, Felicia M.G. Magpantay, Parthasarathy Srinivasan

Mathematics and Statistics Faculty Publications

One of the main challenges for the fresh-food produce industry is to ensure that the produce is free from harmful pathogens. A potential area of risk is due to cross-contamination in a sanitizing chlorine wash-cycle, where the same water is used to wash contaminated as well as non-contaminated produce. However, this is also an area where effective intervention strategies are possible, provided we have a good understanding of the mechanism of cross-contamination. Based on recent experimental work by Luo, Y. et al. A pilot plant scale evaluation of a new process aid for enhancing chlorine efficacy against pathogen survival and …

Circulating Kidney Injury Molecule-1 Levels In Acute Heart Failure : Insights From The Ascend-Hf Trial (Acute Study Of Clinical Effectiveness Of Nesiritide In Decompensated Heart Failure), Justin L. Grodin, Antonio L. Perez, Yuping Wu, Adrian F. Hernandez, Javed Butler, Marco Metra, G. Michael Felker, Adriaan A. Voors, John J. Mcmurray, Paul W. Armstrong, Robert M. Califf, Randall C. Starling, Christopher M. O'Connor, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

Objectives: This study sought to determine the relationship of KIM-1 levels with adverse clinical outcomes in acute decompensated heart failure (ADHF). Background: Kidney injury molecule (KIM)-1 is a biomarker expressed by the nephron in acute tubular injury, and is a sensitive and specific marker for early acute kidney injury. Although commonly measured in urine, KIM-1 levels are also detectable in plasma, but its clinical and prognostic utility in ADHF is unknown. Methods: Baseline, 48- to 72-h, and 30-day KIM-1 plasma levels were measured in 874 subjects in the ASCEND-HF (Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure) …

Wright State University Math And Statistics Department History, Joanne Dombrowski, David Miller

Mathematics and Statistics Faculty Publications

No abstract provided.

Prognostic Role Of Serum Chloride Levels In Acute Decompensated Heart Failure, Justin L. Grodin, Jennifer Simon, Rory Hachamovitch, Yuping Wu, Gregory Jackson, Meghana Halkar, Randall C. Starling, Jeffrey M. Testani, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

BACKGROUND: Acute decompensated heart failure (ADHF) can be complicated by electrolyte abnormalities, but the major focus has been concentrated on the clinical significance of serum sodium levels.

Prevalence And Prediction Of Obstructive Coronary Artery Disease In Patients Referred For Valvular Heart Surgery, Jason M. Lappe, Justin L. Grodin, Yuping Wu, Corinne Bott Silverman, Leslie Cho

Mathematics and Statistics Faculty Publications

Current guidelines recommend a coronary evaluation before valvular heart surgery (VHS). Diagnostic coronary angiography is recommended in patients with known coronary artery disease (CAD) and those with high pretest probability of CAD. In patients with low or intermediate pretest probability of CAD, the guidelines recommend coronary computed tomographic angiography. However, there are no tools available to objectively assess a patient’s risk for obstructive CAD before VHS. To address this deficit, 5,360 patients without histories of CAD who underwent diagnostic coronary angiography as part of preoperative evaluation for VHS were identified. Obstructive CAD was defined as ≥50% stenosis in ≥1 artery. …

New Lower Bounds For The Topological Complexity Of Aspherical Spaces, Mark Grant, Gregory Lupton, John Oprea

Mathematics and Statistics Faculty Publications

We show that the topological complexity of an aspherical space X is bounded below by the cohomological dimension of the direct product A×BA×B, whenever A and B are subgroups of π1(X)π1(X) whose conjugates intersect trivially. For instance, this assumption is satisfied whenever A and B are complementary subgroups of π1(X)π1(X). This gives computable lower bounds for the topological complexity of many groups of interest (including semidirect products, pure braid groups, certain link groups, and Higman's acyclic four-generator group), which in some cases improve upon the standard lower bounds in terms of zero-divisors cup-length. Our results illustrate an intimate relationship between …

Gottlieb Groups Of Function Spaces, Gregory Lupton, Samuel Bruce Smith

Mathematics and Statistics Faculty Publications

We analyze the Gottlieb groups of function spaces. Our results lead to explicit decompositions of the Gottlieb groups of many function spaces map(X,Y)---including the (iterated) free loop space of Y---directly in terms of the Gottlieb groups of Y. More generally, we give explicit decompositions of the generalized Gottlieb groups of map(X,Y) directly in terms of generalized Gottlieb groups of Y. Particular cases of our results relate to the torus homotopy groups of Fox. We draw some consequences for the classification of T-spaces and G-spaces. For X, Y finite and Y simply connected, we give a formula for the ranks of …

Prognostic Role Of Cardiac Power Index In Ambulatory Patients With Advanced Heart Failure, Justin L. Grodin, Wilfried Mullens, Matthias Dupont, Yuping Wu, David O. Taylor, Randall C. Starling, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

BACKGROUND: Cardiac pump function is often quantified by left ventricular ejection fraction by various imaging modalities. As the heart is commonly conceptualized as a hydraulic pump, cardiac power describes the hydraulic function of the heart. We aim to describe the prognostic value of resting cardiac power index (CPI) in ambulatory patients with advanced heart failure. METHODS AND RESULTS: We calculated CPI in 495 sequential ambulatory patients with advanced heart failure who underwent invasive haemodynamic assessment with longitudinal follow-up of adverse outcomes (all-cause mortality, cardiac transplantation, or ventricular assist device placement). The median CPI was 0.44 W/m(2) (interquartile range 0.37, 0.52). …

Comparison Of Robotics, Functional Electrical Stimulation, And Motor Learning Methods For Treatment Of Persistent Upper Extremity Dysfunction After Stroke: A Randomized Controlled Trial, Jessica Mccabe, Michelle Monkiewicz, John P. Holcomb, Svetlana Pundik, Janis J. Daly

Mathematics and Statistics Faculty Publications

Objective

To compare response to upper-limb treatment using robotics plus motor learning (ML) versus functional electrical stimulation (FES) plus ML versus ML alone, according to a measure of complex functional everyday tasks for chronic, severely impaired stroke survivors.

Design

Single-blind, randomized trial.

Setting

Medical center.

Participants

Enrolled subjects (N=39) were >1 year post single stroke (attrition rate=10%; 35 completed the study).

Interventions

All groups received treatment 5d/wk for 5h/d (60 sessions), with unique treatment as follows: ML alone (n=11) (5h/d partial- and whole-task practice of complex functional tasks), robotics plus ML (n=12) (3.5h/d of ML and 1.5h/d of shoulder/elbow robotics), …

The Minimal Zn-Symmetric Graphs That Are Not Zn-Spherical, Lowell Abrams, Dan Slilaty

Mathematics and Statistics Faculty Publications

Given a graph G equipped with faithful and fixed-point-free Γ-action (Γ a finite group) we define an orbit minor H of G to be a minor of G for which the deletion and contraction sets are closed under the Γ-action. The orbit minor H inherits a Γ-symmetry from G, and when the contraction set is acyclic the action inherited by H remains faithful and fixed-point free. When G embeds in the sphere and the Γ-action on G extends to a Γ-action on the entire sphere, we say that G is Γ-spherical. In this paper we determine for every odd value …

Prognostic Comparison Of Different Sensitivity Cardiac Troponin Assays In Stable Heart Failure, Justin L. Grodin, Sarah Neale, Yuping Wu, Stanley L. Hazen, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

Background: Cardiac troponin (cTn) levels offer prognostic information for patients with heart failure. Highly sensitive assays detect levels of cTn much lower than the 99th percentile of standard cTn assays. We hypothesize that cardiac troponin levels measured by a high-sensitivity assay provide better prognostic value compared with cTn levels measured by a standard assay in patients with chronic heart failure. Methods: We measured high-sensitivity cTnT (hs-cTnT) and standard cardiac troponin I (cTnI) levels, as well as amino-terminal pro B-type natriuretic peptide (NT-proBNP) in 504 sequential stable patients with a history of heart failure who underwent elective coronary angiography, without acute …

Tropical Determinant On Transportation Polytopes, Sailaja Gajula, Ivan Soprunov, Jenya Soprunova

Mathematics and Statistics Faculty Publications

Let D^k,l(m, n)be the set of all the integer points in the transportation polytope of kn × ln matrices with row sums lm and column sums km. In this paper we find the sharp lower bound on the tropical determinant over the set D^k,l(m, n). This integer piecewise linear programming problem in arbitrary dimension turns out to be equivalent to an integer non-linear (in fact, quadratic) optimization problem in dimension two. We also compute the sharp upper bound on a modification of the tropical determinant, where the maximum over all the transversals in a matrix is …

Ascent Sequences Avoiding Pairs Of Patterns, Andrew M. Baxter, Lara Pudwell

Mathematics and Statistics Faculty Publications

Ascent sequences were introduced by Bousquet-Melou et al. in connection with (2+2)-avoiding posets and their pattern avoidance properties were first considered by Duncan and Steingrímsson. In this paper, we consider ascent sequences of length n" role="presentation" style="display: inline; font-size: 11.2px; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; font-family: Verdana, Arial, Helvetica, sans-serif; position: relative;">nn avoiding two patterns of length 3, and we determine an exact enumeration for 16 different pairs of patterns. Methods include simple recurrences, bijections to other combinatorial objects (including Dyck paths …

Material Hardship In Families With Children With Health Conditions: Implications For Practice, Patricia Stoddard Dare, Leaanne Derigne, Linda M. Quinn, Christopher Mallett

Mathematics and Statistics Faculty Publications

Cross-sectional data from the third wave of a ten-year data collection initiative were used to assess the odds of experiencing four material hardships between families who have a child member with a limiting health condition, and families with children who do not have a child member with a limiting health condition. The odds of experiencing material hardship in families with more than one child with a limiting health condition were also assessed. In the multivariable models, having a child in the household with a limiting health condition increases the odds the household will be unable to pay bills, and have …

Intestinal Microbiota-Dependent Phosphatidylcholine Metabolites, Diastolic Dysfunction, And Adverse Clinical Outcomes In Chronic Systolic Heart Failure, W.H. Wilson Tang, Zeneng Wang, Kevin Shrestha, Allen G. Borowski, Yuping Wu, Richard W. Troughton, Allan L. Klein, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Background: Trimethylamine-N-oxide (TMAO) has been linked to increased cardiovascular risk. We aimed to determine the prognostic value of TMAO and its dietary precursors, choline and betaine, in heart failure (HF). Methods and Results: In 112 patients with chronic systolic HF with comprehensive echocardiographic evaluation, we measured plasma TMAO, choline, and betaine by mass spectrometry. Median (interquartile range) TMAO levels, choline, and betaine levels were 5.8 (3.6–12.1) μmol/L, 10.9 (8.4–14.0) μmol/L, and 43.8 (37.1–53.0) μmol/L, respectively, and were correlated with each other (all P < .0001 for both). TMAO levels were significantly higher in patients with diabetes mellitus (9.4 [4.9–13.2] vs 4.8 [3.4–9.8] μmol/L; P = .005) and in subjects with New York Heart Association functional class III or greater (7.0 [4.7–14.8] vs 4.7 [3.4–11.3] μmol/L; P = .02). Elevated TMAO, choline, and betaine levels were each associated with higher plasma N-terminal pro–B-type natriuretic peptide (NT-proBNP) levels and more advanced left ventricular diastolic dysfunction, but not systolic dysfunction or inflammatory and endothelial biomarkers. Higher choline (hazard ratio [HR] 1.64, 95% CI 1.22–2.20; P = .001), betaine (HR 1.51, 95% CI 1.10–2.08; P = .01), and TMAO (HR 1.48, 95% CI 1.10–1.96; P = .01) predicted increased risk for 5-year adverse clinical events (death/transplantation). Only higher TMAO levels predicted incident adverse clinical events independently from age, estimated glomerular filtration rate, mitral E/septal Ea, and NT-proBNP levels (HR 1.46, 95% CI 1.03–2.14; P = .03). Conclusion: Elevated plasma TMAO, choline, and betaine levels are each associated with more advanced left ventricular diastolic dysfunction and portend poorer long-term adverse clinical outcomes in chronic systolic HF. However, only higher plasma TMAO was associated with poor prognosis after adjustment for cardiorenal indices.

Gut Microbiota-Dependent Trimethylamine N-Oxide (Tmao) Pathway Contributes To Both Development Of Renal Insufficiency And Mortality Risk In Chronic Kidney Disease, W.H. Wilson Tang, Zeneng Wang, David J. Kennedy, Yuping Wu, Jennifer A. Buffa, Brendan Agatisa Boyle, Xinmin S. Li, Bruce S. Levison, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

RATIONALE: Trimethylamine-N-oxide (TMAO), a gut microbial-dependent metabolite of dietary choline, phosphatidylcholine (lecithin), and l-carnitine, is elevated in chronic kidney diseases (CKD) and associated with coronary artery disease pathogenesis. OBJECTIVE: To both investigate the clinical prognostic value of TMAO in subjects with versus without CKD, and test the hypothesis that TMAO plays a direct contributory role in the development and progression of renal dysfunction. METHODS AND RESULTS: We first examined the relationship between fasting plasma TMAO and all-cause mortality over 5-year follow-up in 521 stable subjects with CKD (estimated glomerular filtration rate, <60 mL/min per 1.73 m(2)). Median TMAO level among CKD subjects was 7.9 μmol/L (interquartile range, 5.2-12.4 μmol/L), which was markedly higher (P<0.001) than in non-CKD subjects (n=3166). Within CKD subjects, higher (fourth versus first quartile) plasma TMAO level was associated with a 2.8-fold increased mortality risk. After adjustments for traditional risk factors, high-sensitivity C-reactive protein, estimated glomerular filtration rate, elevated TMAO levels remained predictive of 5-year mortality risk (hazard ratio, 1.93; 95% confidence interval, 1.13-3.29; P<0.05). TMAO provided significant incremental prognostic value (net reclassification index, 17.26%; P<0.001 and differences in area under receiver operator characteristic curve, 63.26% versus 65.95%; P=0.036). Among non-CKD subjects, elevated TMAO levels portend poorer prognosis within cohorts of high and low cystatin C. In animal models, elevated dietary choline or TMAO directly led to progressive renal tubulointerstitial fibrosis and dysfunction. CONCLUSIONS: Plasma TMAO levels are both elevated in patients with CKD and portend poorer long-term survival. Chronic dietary exposures that increase TMAO directly contributes to progressive renal fibrosis and dysfunction in animal models.

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 …

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.

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 …

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.

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.

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 …

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 …

Unavoidable Minors Of Large 4-Connected Bicircular Matroids, Deborah Chun, Tyler Moss, Dan Slilaty, Xiangqian Zhou

Mathematics and Statistics Faculty Publications

It is known that any 3-connected matroid that is large enough is certain to contain a minor of a given size belonging to one of a few special classes of matroids. This paper proves a similar unavoidable minor result for large 4-connected bicircular matroids. The main result follows from establishing the list of unavoidable minors of large 4-biconnected graphs, which are the graphs representing the 4-connected bicircular matroids. This paper also gives similar results for internally 4-connected and vertically 4-connected bicircular matroids.

Individual-Based Modeling: Mountain Pine Beetle Seasonal Biology In Response To Climate, Jacques Regniere, Barbara J. Bentz, James A. Powell, Remi St-Amant

Mathematics and Statistics Faculty Publications

Over the past decades, as significant advances were made in the availability and accessibility of computing power, individual-based models (IBM) have become increasingly appealing to ecologists (Grimm 1999). The individual-based modeling approachprovides a convenient framework to incorporate detailed knowledge of individuals and of their interactions within populations (Lomnicki 1999). Variability among individuals is essential to the success of populations that are exposed to changing environments, and because natural selection acts on this variability, it is an essential component of population performance. © Springer International Publishing Switzerland 2015.

On Dual Toric Complete Intersection Codes, Pinar Celebi Demiraslan, Ivan Soprunov

Mathematics and Statistics Faculty Publications

In this paper we study duality for evaluation codes on intersections of ℓ hypersurfaces with given ℓ-dimensional Newton polytopes, so called toric complete intersection codes. In particular, we give a condition for such a code to be quasi-self-dual. In the case of it reduces to a combinatorial condition on the Newton polygons. This allows us to give an explicit construction of dual and quasi-self-dual toric complete intersection codes. We provide a list of examples over and an algorithm for producing them.