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NIMBioS Tuesday Seminar Series

Species montage. In conjunction with the interdisciplinary activities of the National Institute for Mathematical and Biological Synthesis (NIMBioS), a seminar series on topics in mathematical biology will be hosted at NIMBioS every other Tuesday at 3:30 p.m. (unless otherwise noted) in Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd. Seminar speakers will focus on their research initiatives at the interface of mathematics and many areas of the life sciences. Light refreshments will be served in Room 206 beginning 30 minutes before each talk. Faculty and students from across the UT community are welcome to join us. The schedule will be supplemented as additional speakers are added.

NIMBioS Interdisciplinary Seminars will resume in January 2016.

Video Archive of NIMBioS Seminars
Archived Seminar Calendars:   2015   2014   2013   2012   2011   2010   2009

Date Speaker
Topic
  January 2016
Jan 19 Chongle Pan, Computer Science and Mathematics Division, ORNL; Microbiology, Univ. of Tennessee Characterization of microbial evolution and physiology using big omics data
  February 2016
Feb 16 Maria Servedio, Biology, Univ. of North Carolina; Handling Editor, Evolution Models and mechanisms of male mate choice
  March 2016
Mar 8
Canceled
Peter Chesson*, Ecology and Evolutionary Biology, Univ. of Arizona Diversity maintenance: New concepts and theory for communities as multiple-scale entities
Mar 22 Alex Mogilner, Mathematics and Biology, Courant Institute; Biology, New York Univ. Mechanical pathways of cell polarization and motility initiation
Mar 29 Alison G. Power, Ecology and Evolutionary Biology, Cornell Univ. From landscapes to coinfections: Plant virus epidemiology at multiple scales
  April 2016
Apr 12 Michael Whitlock*, Zoology, Univ. of British Columbia, Vancouver Selection in complex spatial settings
Apr 14 Glenn Ledder, Mathematics, Univ. of Nebraska, Lincoln; NIMBioS Sabbatical Fellow Allocation of resources in two-component systems
Apr 19 Urszula Ledzewicz*, Mathematics and Statistics, Southern Illinois Univ., Edwardsville, and Lodz Univ. of Technology, Poland Optimal protocols for combination therapies in cancer: How much, how often, in what sequence?
  August 2016
Aug 23 Sergei Tarasov, NIMBioS postdoctoral fellow TBA
  September 2016
Sep 6 Nourridine Siewe, NIMBioS postdoctoral fellow (Aug 2016) TBA
Sep 20 Sarah Flanagan, NIMBioS postdoctoral fellow (Sep 2016) TBA
  October 2016
Oct 4 Lauren Smith, NIMBioS postdoctoral fellow (Sep 2016) TBA
Oct 18 Jay M. Ver Hoef*, National Marine Mammal Laboratory, NOAA-NMFS Alaska Fisheries Science Center Modern spatial statistics: Basis functions, convolutions, and big data
  January 2017
Jan 17 Andrew Rominger, NIMBioS postdoctoral fellow (Jan 2017) TBA
Jan 31 Oyita Udiani, NIMBioS postdoctoral fellow (Jan 2017) TBA
  February 2017
Feb 14 Klaus Schulten*, Beckman Institute, Univ. of Illinois, Urbana TBA
*NIMBioS Postdoctoral Fellows Invited Distinguished Visitor

NIMBioS Spring 2016 Interdisciplinary Seminar Series: Printable Flyer

Seminar Abstracts:


U. Ledzewicz photo. Time/Date: 3:30 Tuesday, April 19
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker:Urszula Ledzewicz, Mathematics and Statistics, Southern Illinois Univ., Edwardsville, and Lodz Univ. of Technology, Poland; NIMBioS Postdoctoral Fellows Invited Distinguished Visitor
Topic: Optimal protocols for combination therapies in cancer: How much, how often, in what sequence?   Joint research with Heinz Schaettler (Washington Univ., St. Louis, USA).
Abstract: The questions "how much, how often, and in what sequence" anticancer drugs should be given to secure an optimal outcome are essential and far from being answered yet. Also, simple answers are not always the best ones. Actually, there is mounting medical evidence that "more is not necessarily better" and a properly calibrated dose which takes into account this complexity can lead to a better outcome. This has generated a search for what is called the biologically optimal dose (BOD) in the medical literature. Formulating mathematical models with an objective that reflects the overall goal of the therapy, like minimizing the tumor size and side effects, maximizing the actions of the immune system etc., leads to optimal control problems where mathematical analysis can answer some of these questions in a theoretical framework. In this talk, we present some of these problems, addressing challenges and open questions. The results of the analysis will be compared with medical and experimental data. Click here for more information.
Seminar flyer (pdf).

. Ledder photo. Time/Date: 3:30 Thursday, April 14
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Glenn Ledder, Mathematics, Univ. of Nebraska, Lincoln; NIMBioS Sabbatical Fellow
Topic: Allocation of resources in two-component systems
Abstract: How plants allocate resources towards different functions, such as light-absorption by shoots versus nutrient and water-absorption by roots, is a critical determinant of their growth and survival. Yet, the mechanisms underlying such differential allocation in heterogeneous environments are unknown. It is generally thought that plants allocate resources to achieve optimal growth, but this would require central planning, a capacity that plants are unlikely to have. An alternative hypothesis is that differential allocation is accomplished through local allocation rules operating independently in roots and shoots, with each of these components acting selfishly, as happens in obligate syntrophy. We describe a simple model for a plant as a system of "roots" and "shoots" that collect "carbon" and "nitrogen," respectively. Nitrogen collected by roots is sent directly to a root synthesizing unit to be combined with carbon into new root tissue. Any excess (unused) nitrogen is passed from the roots to the shoots. Similarly, carbon collected by shoots goes to the shoot synthesizing unit, with any excess sent to the roots. Analysis shows that this selfish allocation protocol manages to yield patterns consistent with those generated by a model of optimal plant growth, for synthesizing unit models defined with both a simplified Liebig minimum rule and a more realistic co-limitation model. Click here for more information. Seminar flyer (pdf).
Video icon.Watch seminar online.


M. Whitlock photo. Time/Date: 3:30 Tuesday, April 12
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Michael Whitlock, Zoology, Univ. of British Columbia, Vancouver; NIMBioS Postdoctoral Fellows Invited Distinguished Visitor
Topic: Selection in complex spatial settings
Abstract: The fact that the individuals in each species are spread over space with limited dispersal means that evolutionary processes are all to some extent local. In this talk I will discuss some ways in which the basic processes of evolution—especially selection and drift—are substantially changed by their spatial context. In spatially structured populations (compared to the panmictic populations that are better studied), deleterious alleles are likely to be more effectively removed by selection at equilibrium. In contrast, in non-equilibrium populations expanding over space, deleterious alleles can reach locally high frequencies through allelic surfing. The "expansion load" that results can be a substantial burden on the mean fitness of a population. I will explore the interaction between deleterious mutations and spatially heterogeneous selection in determining the rate of population range expansion and the amount of genetic load that results. Click here for more information. Seminar flyer (pdf).
Video icon.Watch seminar online.


A. Power photo. Time/Date: 3:30 Tuesday, March 29
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Alison G. Power, Ecology and Evolutionary Biology, Cornell Univ.
Topic: From landscapes to coinfections: Plant virus epidemiology at multiple scales
Abstract: Infections of a single host by multiple pathogens are common in nature but relatively poorly studied compared to single infections. In this talk I will discuss the causes and consequences of coinfection by insect-transmitted plant viruses in two systems: 1) the multiple species of barley/cereal yellow dwarf viruses (B/CYDVs) infecting wild grasses across Western US grasslands; and 2) the multiple strains of potato virus Y infecting potatoes and other solanaceous plants on farms in upstate New York. Our research is addressing the drivers of virus emergence and spread at multiple scales, including the landscape, the field, and within individual host plants. I will present data on the influence of landscape structure, vector community composition, transmission dynamics, and within-host processes on the epidemiology of these aphid-transmitted viruses. Click here for more information. Seminar flyer (pdf).

A. Mogilner photo. Time/Date: 3:30 Tuesday, March 22
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Alex Mogilner, Mathematics and Biology, Courant Institute; Biology, New York Univ.
Topic: Mechanical pathways of cell polarization and motility initiation
Abstract: Animal cells move using a polarized dynamic actomyosin network adhering to the surface. While mechanics of motility based on actin protrusion at the front and myosin contraction at the rear are understood fairly well, explanation of spontaneous polarization remains elusive. I will present simulations of a 2D model of a viscous contractile actin-myosin network with a free boundary which, coupled with experimental data, suggests that a positive feedback between myosin aggregation and actin flow and a negative feedback between flow and stick-slip adhesion is the key to understanding self polarization of fish epithelial keratocytes. The model predicts, and experiments confirm, that upregulating myosin accelerates the polarization. On the other hand, epithelial IAR-2 cells self-polarize faster if myosin is inhibited. In that case, combined experiment and theory point out that competition of protruding and contracting actin networks for a common actin pool, coupled with cell movement, is the key to the self-polarization. I will discuss implications of these findings for design principles of cellular self-organization. Click here for more information. Seminar flyer (pdf)
Video icon.Watch seminar online.


P. Chesson photo. This seminar has been canceled.
Time/Date: 3:30 Tuesday, March 8
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Peter Chesson, Ecology and Evolutionary Biology, Univ. of Arizona, and NIMBioS Postdoctoral Fellows Invited Distinguished Visitor
Topic: Diversity maintenance: New concepts and theory for communities as multiple-scale entities
Abstract: Current approaches to community assembly, species coexistence, and the maintenance of biodiversity focus on the coexistence of species on small areas of habitat, which are assumed to support self-sustaining biological communities. The local communities on these areas are assumed to be assembled from the regional set of species according to local environmental conditions and interactions between species. However, local communities are not natural ecological entities in most cases, but are defined more by convenience for study. In general, local communities are affected by immigration on ecological time scales, and so do not satisfy the requirements for most theories of coexistence and diversity maintenance. For any given unit of space on a given scale, scale transition theory reveals how much diversity can be explained by processes taking place within that unit of space compared with contributions from other spatial units or other scales. I use scale transition theory to show how the joint contributions of multiple mechanisms of coexistence can be studied. These mechanisms include point mechanisms, such as resource partitioning, spatial mechanisms such as the spatial storage effect and fitness-density covariance, and temporal mechanisms such as the temporal storage effect. This multi-scale community theory removes the artificial distinction between the local community and the species pool. Instead, it shows how the species pool and the local community are mutually dependent, with scale-dependent properties. The measures of mechanism strength from scale transition theory can be operationalized for field and experimental studies, and provide rigorous approaches to the study of coexistence in natural communities as multiple scale entities. Click here for more information. Seminar flyer (pdf).

M. Servedio photo. Time/Date: 3:30 p.m. Tuesday, February 16
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Maria Servedio, Biology, Univ. of North Carolina; Handling Editor, Evolution
Topic: Models and mechanisms of male mate choice
Abstract: Male mate choice in polygynous systems differs from female mate choice in fundamental ways. Mathematical models of the process uncover a hidden competition cost that makes the evolution of male preferences very difficult. I will first present a null model that pinpoints this cost. I will then explore three categories of mechanisms that would seem to have the potential to allow male preferences to evolve despite this cost: characteristics of the female trait, characteristics of the male behavior, and alterations of the mating system. Click here for more information. Seminar flyer (pdf).
Video icon.Watch seminar online.


C. Pan photo. Time/Date: 3:30 p.m. Tuesday, January 19
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Chongle Pan, Computer Science and Mathematics Division, Oak Ridge National Laboratory; Microbiology, Univ. of Tennessee
Topic: Characterization of microbial evolution and physiology using big omics data
Abstract: Genomics and other -omics analyses can provide large amounts of data to elucidate the evolution and physiology of microorganisms. A functional phylogenomics study was performed to characterize the evolution of metabolic functions in Bacteria and Archaea. A total of 14,727 GenBank prokaryotic genomes were re-annotated using a new protein family database, UniFam, to obtain consistent functional annotations. The consistency between the distribution of metabolic pathways in genomes and the phylogenetic tree of genomes was measured using parsimony scores and retention indices. Function-phylogeny correlation identified a set of clade-specific metabolic pathways with low parsimony scores. Many other metabolic pathways were sparsely dispersed across many clades with high parsimony scores, which indicated their frequent horizontal gene transfers. Many plant-associated fungi host symbiotic endobacteria with reduced genomes. We integrated proteomics and metabolomics to characterize the endobacterium Candidatus Glomeribacter sp. and the root endophytic fungus Mortierella elongata. The endobacterium likely extracted malate from the fungal host as the primary carbon substrate for energy production and biosynthesis. Further, nitrogen limitation significantly perturbed the carbon and nitrogen flows in the fungal metabolic network. M. elongata regulated many pathways by concordant changes on enzyme abundances, post-translational modifications, reactant concentrations, and allosteric effectors. Such multimodal regulations may be a general mechanism for metabolic modulation. Click here for more information. Seminar flyer (pdf).