Departmental Tea
Hosted by the Graduate Student Council. All are welcome to come mingle over coffee, tea, and cookies!
Date:
-
Location:
745 Patterson Office Tower
Event Series:
Film Screening and Discussion with Fran Ansley
The UK Appalachian Center welcomes Fran Ansley on Thursday, November 6, 2014 at 6:30 p.m. Dr. Ansley will screen and discuss the bilingual film Morristown: In the Air and Sun. This event is free and open to the public and will be held at the Village Branch Public Library at 2185 Versailles Rd., Lexington, KY.
Date:
-
Location:
Village Branch Public Library, 2185 Versailles Road, Lexington, KY
Event Series:
Discrete CATS Seminar
Title: An Algebraic Approach to Systems Biology.
Abstract: This talk will present an algebraic perspective for modeling gene regulatory networks. Algebraic models can be represented by polynomials over finite fields. In this setting, several problems relevant to biology can be studied. For instance, the algebraic view has been successfully applied for the development of computational tools to determine the attractors of Boolean Networks, for network inference algorithms, and for the development of a theoretical framework for agent based models. In this talk, the algebraic perspective of discrete models will be applied for control problems. No background in mathematical biology will be assumed for this talk.
Date:
-
Location:
745 Patterson Office Tower
Event Series:
Topology Seminar
Title: Limits, Colimits, and Homotopy . . . Oh, my!
Abstract: Given maps f: X --> Y and g: X --> Z of topological spaces, we obtain a unique map h: X --> Y x Z that respects the appropriate projections. This property corresponds more generally to the limit of a diagram of spaces. In this talk, we will define the limit, colimit, and their homotopy analogs and discuss their universal properties and relative merits/uses. No prior topological knowledge is assumed.
Date:
-
Location:
745 Patterson Office Tower
Event Series:
Applied Math Seminar
Title: Modeling Foot and Mouth Disease in cattle in northern Cameroon
Abstract: Foot and Mouth Disease (FMD) is endemic in cattle in the Far North Region of Cameroon. While many cattle herds remain in a fixed location throughout the year, there are a small number of mobile herds that migrate depending on the season. These mobile herds share grazing space with many other cattle throughout the year, leading to increased disease transmission. In this talk I will present a multi-scale agent-based simulation model of FMD in northern Cameroon, focusing on the mathematical SIRS epidemic model running both inter- and intra-herd. Various parameters are determined by data from researchers on the ground while others are determined via in silico experimentation. The goal of the first phase of the project is to determine how each herd type contributes to the overall number of secondary infections. This model is a work in progress and the talk is meant to stimulate discussion about means of incorporating epidemic models in a multi-scale setting.
Date:
-
Location:
145 Patterson Office Tower
Event Series:
Seminar on Algebra and Geometry
Title: Tropical plane quartics
Abstract: I will begin with a brief introduction to tropical geometry, and explain how algebraic curves give rise to tropical curves. I will then show that every tropical plane quartic admits 7 families of bitangent lines. This is analogous to the remarkable fact in classical geometry that a smooth plane quartic has exactly 28 bitangent lines. While the proof is purely combinatorial, I will discuss recent developments which suggest that the classical and tropical results are closely related. This is joint work with Matt Baker, Ralph Morrison, Nathan Pflueger, and Qingchun Ren.
Date:
-
Location:
745 Patterson Office Tower
Event Series:
Graduate Student Colloquium
Title: An Introduction to Differential Forms
Abstract: The theory of differential forms is a beautiful subject that has particular importance in geometry, topology and physics. Our focus will be on how differential forms provide a better approach to multi-variable calculus. Specifically, we will see that many ostensibly unrelated results are unified using differential forms. Time permitted, we will introduce de Rham cohomology, a cohomology theory based on differential forms.
Date:
-
Location:
745 Patterson Office Tower
Event Series:
Astro Seminar: Surprising New Insights into Quasars from the WISE Satellite
Abstract:
We now believe that every large galaxy hosts a supermassive black
hole at its core, with masses ranging from millions to billions of
times that of our Sun. At times, these black holes are actively
accreting, causing the nuclei of the galaxies to shine brightly
across the electromagnetic spectrum. However, in many, perhaps
most quasars, obscuring material along the line of sight shields
us from directly viewing the inner nucleus. This obscuring material
is heated, and emits strongly in the mid-infrared. The Wide-field
Infrared Survey Explorer, or WISE, has recently mapped the entire
sky in mid-infrared light with exquisite depth and clarity. WISE
has allowed us to find luminous quasars across the whole sky due
to this heated material, more than tripling the number of quasars
known. I will discuss several surprising new insights into quasars
that have come out of this work. In brief, the dominant paradigms
do not match our observations, with potentially important implications
for the role of quasars in the growth of galaxies. I will conclude
by discussing how these studies will be further enabled by the
Euclid and WFIRST satellites.
Date:
-
Location:
CP179
Event Series:
Nuclear Seminar: A High Precision Test of the Equivalence Principle
Date:
-
Location:
CP179
Event Series:
Condensed Matter Seminar: Constraints on topological order in Mott insulators
The hunt for anyonic excitations in quantum magnets is frustrated by the absence of any order parameter that could be used to detect such phases. Consequently a very important ally is the Hastings-Oshikawa-Lieb-Schultz-Mattis theorem for 2D quantum magnets, which guarantees that a fully symmetric gapped Mott insulator must be topologically ordered, though is silent on which topological order is permitted. After introducing the HOLSM theorem, I will explain a new line of argument that constrains which topological order is permitted in a symmetric gapped Mott insulator. For example, I'll show that a fully symmetric magnet with S = 1/2 per unit cell cannot be in the double-semion topological phase. An application of our result is to the Kagome lattice quantum antiferromagnet where recent numerical calculations of entanglement entropy indicate a ground state compatible with either toric code or double semion topological order. Our result rules out the latter possibility.
Date:
-
Location:
CP179
Event Series:
