Physical Sciences and Mathematics Commons^™

Gender Representation On Journal Editorial Boards In The Mathematical Sciences, Chad M. Topaz, Shilad Sen

Chad M. Topaz

No abstract provided.

Topological Data Analysis Of Biological Aggregation Models, Chad M. Topaz, Lori B. Ziegelmeir, Tom Halverson

Chad M. Topaz

No abstract provided.

Biological Aggregation Driven By Social And Environmental Factors: A Nonlocal Model And It Degenerate Cahn-Hilliard Approximation, Andrew J. Bernoff, Chad Topaz

Chad M. Topaz

No abstract provided.

Flipped Calculus: A Study Of Student Performance And Perceptions, Lori B. Ziegelmeir, Chad M. Topaz

Chad M. Topaz

No abstract provided.

Flipped Calculus: A Study Of Student Performance And Perceptions, Lori Beth Ziegelmeier, Chad M. Topaz

Chad M. Topaz

No abstract provided.

Topological Data Analysis Of Biological Aggregation Models, Chad M. Topaz, Lori Ziegelmeier, Tom Halverson

Chad M. Topaz

Social Aggregation In Pea Aphids: Experiment And Random Walk Modeling, Christa Nilsen, John Paige, Olivia Warner, Benjamin Mayhew, Ryan Sutley, Mathew Lam, Andrew J. Bernoff, Chad M. Topaz

Chad M. Topaz

No abstract provided.

Nonlocal Aggregation Equations: A Primer Of Swarm Equilibria, Chad Topaz, Andrew Bernoff

Chad M. Topaz

No abstract provided.

Instabilities And Patterns In Coupled Reaction-Diffusion Layers, Anne J. Catlla, Amelia Mcnamara, Chad M. Topaz

Chad M. Topaz

We study instabilities and pattern formation in reaction-diffusion layers that are diffusively coupled. For two-layer systems of identical two-component reactions, we analyze the stability of homogeneous steady states by exploiting the block symmetric structure of the linear problem. There are eight possible primary bifurcation scenarios, including a Turing-Turing bifurcation that involves two disparate length scales whose ratio may be tuned via the interlayer coupling. For systems of n-component layers and nonidentical layers, the linear problem’s block form allows approximate decomposition into lower-dimensional linear problems if the coupling is sufficiently weak. As an example, we apply these results to a two-layer …

A Primer Of Swarm Equilibria, Andrew J. Bernoff, Chad M. Topaz

Chad M. Topaz

We study equilibrium configurations of swarming biological organisms subject to exogenous and pairwise endogenous forces. Beginning with a discrete dynamical model, we derive a variational description of the corresponding continuum population density. Equilibrium solutions are extrema of an energy functional, and satisfy a Fredholm integral equation. We find conditions for the extrema to be local minimizers, global minimizers, and minimizers with respect to infinitesimal Lagrangian displacements of mass. In one spatial dimension, for a variety of exogenous forces, endogenous forces, and domain configurations, we find exact analytical expressions for the equilibria. These agree closely with numerical simulations of the underlying …

Forced Patterns Near A Turing-Hopf Bifurcation, Chad M. Topaz, Anne Catlla

Chad M. Topaz

We study time-periodic forcing of spatially-extended patterns near a Turing-Hopf bifurcation point. A symmetry-based normal form analysis yields several predictions, including that (i) weak forcing near the intrinsic Hopf frequency enhances or suppresses the Turing amplitude by an amount that scales quadratically with the forcing strength, and (ii) the strongest effect is seen for forcing that is detuned from the Hopf frequency. To apply our results to specific models, we perform a perturbation analysis on general two-component reaction-diffusion systems, which reveals whether the forcing suppresses or enhances the spatial pattern. For the suppressing case, our results explain features of previous …

Review Of “Continuum Modeling In The Physical Sciences” By Van Groesen And Molenaar, Chad M. Topaz

Chad M. Topaz

No abstract provided.

Tuberculosis Screening For International Students At A Midwestern Liberal Arts College, Grace Goetzke, Victor Addona, Chad M. Topaz

Chad M. Topaz

Participants: 318 international students at Macalester College screened for latent tuberculosis infection via tuberculin skin tests (TST) from 2004-2008. Objective: To estimate positive TST probability based on countries of residency and history of BCG vaccination. Methods and Results: 52% of students had a positive TST. Logistic regression modeling shows that a positive TST is insignificantly correlated with history of BCG vaccination (p=0.910) but is significantly negatively correlated with residence in the European Union (p=0.00502) and the Middle East (p=0.00451), and positively correlated with residence in North America (p=0.00151). Conclusions: There is a significant relationship between TST result and residence in …