The Mathematics Calendar
http://www.math.psu.edu/seminars/calendar.php
Seminars and special events the Pennsylvania State University Mathematics Department2015-01-25webmaster@math.psu.eduModeling Blood Cell-Substrate Interaction and Biofilm-Fluid Interaction
http://www.math.psu.edu/seminars/meeting.php?id=26480
Speaker(s): Zhiliang Xu
This is an introductory talk for the CAM Colloquium.2015-01-26T12:20:00CCMA Luncheon Seminarshaffer@math.psu.eduliu@math.psu.eduModeling Blood Cell-Substrate Interaction and Biofilm-Fluid Interaction
http://www.math.psu.edu/seminars/meeting.php?id=25560
Speaker(s): Zhiliang Xu
In this talk, two different models will be discussed. The first model is for studying blood cell-environment interaction, specially platelet-blood vessel wall interaction. Platelets aggregation at the injury site of the blood vessel occurring via platelet-platelet adhesion, tethering and rolling on the injured endothelium is a critical initial step in blood clot formation. To understand this critical step, a hybrid model is developed to represent membranes of biological cells and the distributed-Lagrange-multiplier/fictitious-domain (DLM/FD) formulation is used for simulating the fluid-cell interactions. For modeling cell-substrate adhesion, a stochastic receptor-ligand binding submodel is used. In the second part of the talk, a biofilm model which systemically couples bacterial, extracellular polymeric substances (EPS) and solvent phases in biofilm will be discussed. The model is derived by using energetic variational approach and phase-field method coupling different phases together. An unconditionally energy-stable numerical splitting scheme is implemented for computing numerical solution of the model efficiently.2015-01-26T14:30:00Computational and Applied Mathematics Colloquiumshaffer@math.psu.eduliu@math.psu.edufuw7@math.psu.eduLeafwise entropy rigidity for foliations.
http://www.math.psu.edu/seminars/meeting.php?id=24792
Speaker(s): Christopher Connell
We prove an entropy rigidity statement for general foliated maps f: M --> N between compact foliated spaces in the sense of Besson, Courtois and Gallot. In particular, we establish an iso-entropic inequality with respect to a transverse quasi-invariant measure which is optimal when almost every leaf of M is locally symmetric. We give some applications of this as well, and indicate how it relates to the entropy rigidity conjecture for higher rank spaces. This is joint work with Zhenyu Li.2015-01-26T15:35:00Dynamical systems seminarkatok_s@math.psu.edusaz11@math.psu.edukatok_a@math.psu.eduhertz@math.psu.eduMathematical modeling of malaria transmission
http://www.math.psu.edu/seminars/meeting.php?id=24692
Speaker(s): Olivia Prosper
Sir Ronald Rossâ€™ discovery of the transmission mechanism of malaria in 1897 inspired a suite of mathematical
models for the transmission of vector-borne disease, known as Ross-Macdonald models. I introduce a common
formulation of the Ross-Macdonald model and discuss its extension to address a current topic in malaria control:
the introduction of malaria vaccines. Following over two decades of research, vaccine trials for the malaria
vaccine RTS,S have been completed, demonstrating an efficacy of roughly 50% in young children. Regions with
high malaria prevalence tend to have high levels of naturally acquired immunity (NAI) to severe malaria, leading
to large asymptomatic populations. I introduce a malaria model developed to address concerns about how these
vaccines will perform in regions with existing NAI, discuss some analytic results and their public health
implications, and reframe our question as an optimal control problem.2015-01-27T13:00:00Theoretical Biology Seminartreluga@math.psu.educpc16@math.psu.eduTBA
http://www.math.psu.edu/seminars/meeting.php?id=24740
Speaker(s): Nick Early
2015-01-27T14:30:00GAP Seminarping@math.psu.edustienon@math.psu.eduhigson@math.psu.eduroyer@math.psu.eduFourier dimension and its modifications
http://www.math.psu.edu/seminars/meeting.php?id=24811
Speaker(s): Joerg Schmeling
Fourier dimension has proved to be a useful tool to estimate Hausdorff dimensions of subsets of $\mathbb{R}^n$. It is also used in metric number theory and harmonic analysis. However it is not really justified to call it a dimension. We will investigate stability of the Fourier dimension under unions of sets and give positive results as well as counterexamples. As an outcome of these studies we will propose a modification of the Fourier dimension. This modification regularizes this notion in several ways. First it behaves like a dimension. It also has an important counterpart for measures. In particular we can show that the set of Borel measures having a given Fourier dimension is determined by its joint zero sets.2015-01-27T14:30:00Center for Dynamics and Geometry Colloquiumkatok_s@math.psu.edusaz11@math.psu.edukatok_a@math.psu.eduhertz@math.psu.eduHilbert's Tenth Problem for subrings of the rationals and number fields.
http://www.math.psu.edu/seminars/meeting.php?id=24901
Speaker(s): Kirsten EisentrĂ¤ger
In 1970 Matiyasevich, building on work by Davis, Putnam and Robinson, proved that Hilbert's Tenth Problem is undecidable. Since then, analogues of this problem have been studied by considering polynomial equations over commutative rings other than the integers. The biggest open problem in the area is Hilbert's Tenth Problem over the rational numbers and over number fields in general. In this talk we will construct some subrings $R$ of the rationals that have the property that Hilbert's Tenth Problem for $R$ is Turing equivalent to Hilbert's Tenth Problem over the rationals. We will show that the same can be done for number fields. The rings will be constructed with a priority argument.2015-01-27T14:30:00Logic Seminarreimann@math.psu.edusimpson@math.psu.edujmr71@math.psu.eduIntroduction to KAK theory.0. Local linearization of circle diffeomorphisms with Diophantine rotation number
http://www.math.psu.edu/seminars/meeting.php?id=25356
Speaker(s): Federico Rodriguez Hertz
2015-01-27T15:30:00Working Seminar: Dynamics and its Working Toolskatok_a@math.psu.edusaz11@math.psu.eduhertz@math.psu.edukalinin@math.psu.eduVariational principles for isometric embeddings and rigidity
http://www.math.psu.edu/seminars/meeting.php?id=25464
Speaker(s): Ivan Izmestiev
The discrete total scalar curvature of a manifold glued from euclidean (or hyperbolic) simplices is the sum of the lengths of edges multiplied with the angular defects around them (a volume term is added in the hyperbolic case). This functional has very nice variational properties with respect to the length variables: its critical points correspond to vanishing angle defects, that is to constant curvature metrics. In certain cases we are able to determine the signature of its second variation, which looks very much like that of its smooth counterpart. We will present some applications to isometric embeddings and rigidity.2015-01-28T12:05:00Geometry Luncheon Seminarburago@math.psu.edusaz11@math.psu.eduStability of steady states of the Navier-Stokes-Poisson equations with non-flat doping profile
http://www.math.psu.edu/seminars/meeting.php?id=25323
Speaker(s): Yong Wang
We consider the stability of the steady state of the compressible Navier-Stokes-Poisson equations with the non-flat doping profile. We prove the global existence of classical solutions near the steady state for the large doping profile. For the small doping profile, we prove the time decay rates of the solution provided that the initial perturbation belongs to L^p with 1=< p< 3/2.2015-01-28T15:30:00Complex Fluids Seminartxh35@math.psu.edufuy3@math.psu.eduDescent for specializations of Galois branched covers
http://www.math.psu.edu/seminars/meeting.php?id=24842
Speaker(s): Ryan Eberhart
Let G be a finite group and K a number field. Hilbert's irreducibility theorem states that a regular G-Galois branched cover of P^1_K, the projective line over K, gives rise to G-Galois field extensions of K by specializing the cover (i.e. plugging in specific coordinates into the equations for the cover). A common tactic for progress on the Inverse Galois Problem over Q is to construct a G-Galois branched cover of P^1_Q. We investigate a related line of inquiry: given a G-Galois branched of P^1_K, do any of the specializations descend to a G-Galois field extension of Q, even though the cover itself may not? We prove that the answer is yes when G is cyclic if one allows specializations at closed points. However, we show that the answer is in general no if we restrict to specializations at K-rational points. This is joint work with Hilaf Hasson.2015-01-29T11:15:00Algebra and Number Theory Seminarrvaughan@math.psu.edupapikian@math.psu.eduyee@math.psu.edueisentra@math.psu.eduOka principle: commutative and noncommutative. I
http://www.math.psu.edu/seminars/meeting.php?id=25484
Speaker(s): Nigel Higson
The original Oka principle asserts that smooth vector bundles on closed, complex submanifolds of complex affine space admit unique holomorphic structures. It has obvious implications for K-theory, and, through them, potential applications to noncommutative geometry, especially to the Baum-Connes conjecture. I'll discuss the original result (due to Oka and Grauert), and then actual as well as potential extensions to the noncommutative context.2015-01-29T14:30:00Noncommutative Geometry Seminarhigson@math.psu.edusaz11@math.psu.eduFaculty Meeting
http://www.math.psu.edu/seminars/meeting.php?id=24919
Speaker(s): Faculty Meeting
2015-01-29T15:30:00Department of Mathematics Colloquiumsaz11@math.psu.eduliu@math.psu.eduNonlinear approximation theory for the homogeneous Boltzmann equation
http://www.math.psu.edu/seminars/meeting.php?id=25851
Speaker(s): Binh Tran
A challenging problem in solving the Boltzmann equation numerically is that the velocity space is approximated by a finite region. Therefore, most methods are based on a truncation technique and the computational cost is then very high if the velocity domain is large. Moreover, sometimes, non-physical conditions have to be imposed on the equation in order to keep the velocity domain bounded. In this talk, we introduce the first nonlinear approximation theory for the Boltzmann equation. Our nonlinear wavelet approximation is non-truncated and based on a nonlinear, adaptive spectral method associated with a new wavelet filtering technique and a new formulation of the equation. The approximation is proved to converge and perfectly preserve most of the properties of the homogeneous Boltzmann equation. It could also be considered as a general frame work for approximating kinetic integral equations.2015-01-30T15:30:00CCMA PDEs and Numerical Methods Seminar Seriesfuw7@math.psu.edusaz11@math.psu.edusxw58@math.psu.eduqiao_c@math.psu.edu