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NIMBioS Tuesday Seminar Series - Spring 2015

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.

Video Archive of NIMBioS Seminars

Date Speaker
Topic
  January 2015
Jan 27 Suzanne O'Regan, NIMBioS postdoctoral fellow Video icon. Detecting critical transitions in infectious disease dynamics
  February 2015
**Feb 10
10:30 a.m.
Rm 105
Dr. Stacy Krueger-Hadfield, Grice Marine Laboratory, College of Charleston Brokedown life cycles: Implications of the haploid-diploid life cycle on macroalgal population genetics
Feb 10 Michael Lynch*, Biology, Indiana Univ., Bloomington Video icon. Mutation, drift and the origin of subcellular features
Feb 24
Canceled
Caroline Farrior, NIMBioS postdoctoral fellow Plant traits and the importance of competition among individuals
**Feb 25
9 a.m.
Julio Ramirez, Division of Infectious Diseases, Univ. of Louisville Pneumonia: Clinical & translational research at the University of Louisville
  March 2015
Mar 10 Laurent Excoffier*, Population Genetics CMPG Lab, Institute of Ecology and Evolution, Univ. of Bern Consequences of spatial expansions on population functional diversity
Mar 31 Xiaopeng Zhao, Mechanical, Aerospace, and Biomedical Engineering, Univ. of Tennessee, Knoxville TBA
Apr 7 Caroline Farrior, NIMBioS postdoctoral fellow Plant traits and the importance of competition among individuals
  April 2015
Apr 21 Dr. Mats Gyllenberg, Mathematics and Statistics, Univ. of Helsinki Functional responses and how they evolve by natural selection
  April 2016
Apr 12 Michael Whitlock*, Zoology, Univ. of British Columbia, Vancouver TBA
*NIMBioS Postdoctoral Fellows Invited Distinguished Visitor
**NIMBioS Special Seminar

NIMBioS Seminar Abstracts:


C. Farrior photo. Time/Date: 3:30 p.m., Tuesday, April 7
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Caroline Farrior, NIMBioS postdoctoral fellow
Topic: Plant traits and the importance of competition among individuals
Abstract: Plant communities are complex systems. The success of an individual depends not only on that individual's strategy and its match to the environment, but also on the strategies of other individuals within the community. One of the most noticeable structures in forests, wood, is a great example of this. Wood itself is not a productive tissue, but aids plants in competition with one another for light. So, in order to understand and predict changes in allocation to wood, we must scale from the environment and plant physiology, through individual-level competition, and up to population dynamics and finally landscape-level properties. I will present a model that makes these scale transitions for plants in competition for light, water, and nutrients, and use it to explain empirical phenomena including (1) dominant tradeoffs in allocation patterns in forests and (2) complex plant responses to simple resource addition experiments. In addition, I will introduce plans for expanding this framework to incorporate the pressure of rare disturbances as a potential driver of coexistence of important plant traits. Click here for more information. Seminar flyer (pdf).

L. Excoffier photo. Time/Date: 3:30 p.m. p.m., Tuesday, March 10
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Laurent Excoffier, Population Genetics CMPG Lab, Institute of Ecology and Evolution, Univ. of Bern; NIMBioS Postdoctoral Fellows Invited Distinguished Visitor
Co-author: Stephan Peischl, Population Genetics CMPG Lab, Institute of Ecology and Evolution, Univ. of Bern
Topic: Consequences of spatial expansions on population functional diversity
Abstract: It is known that spatial expansions have had a major influence on population genetic diversity: some neutral variants can increase in frequency and spread over large areas in newly occupied territories. This is the phenomenon of gene surfing. However, selected variants can also surf and thus modify the fitness of expanding populations. We have studied this phenomenon by simulations and by analytical derivations in relatively simple models of expansions in homogeneous environments. Very generally, we find that the fitness of populations located on the expansion front decreases proportionally to their distance from the origin of the expansion. The creation of this expansion load happens in 1D or 2D expansions, in case of hard or soft selection, in presence or absence of recombination and for different distribution of fitness effects. The evolutionary dynamics of this expansion load differs between cases, and also depends on the level of dominance between variants. All these cases will be briefly presented, and we will conclude by showing some evidence that this phenomenon also occurred in human populations. Click here for more information.

J. Ramirez photo. Time/Date: 9:00 a.m., Wednesday, February 25
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Julio Ramirez, Chief, Division of Infectious Diseases, Univ. of Louisville
Topic: Clinical and translational research at the University of Louisville
Abstract: The objectives of this Special Seminar at NIMBioS are to review current research projects in the field of pulmonary infections; to describe the pathogenesis of pneumonia in relation to pathogen, host, and antimicrobial therapy; to explain the role of lung and systemic inflammatory response in lung injury and lung repair; and to review clinical outcomes in patients with pneumonia. Click here for more information. Seminar flyer (pdf).

S. Krueger-Hadfield photo. Time/Date: 10:30 a.m., Tuesday, February 10
Location: Room 105, Claxton Building, 1122 Volunteer Blvd.
Speaker: Stacy Krueger-Hadfield, Grice Marine Laboratory, College of Charleston
Topic: Brokedown life cycles: Implications of the haploid-diploid life cycle on macroalgal population genetics
Abstract: Many macroalgal life cycles alternate between free-living diploid and haploid stages. Very few studies have addressed population genetic structure and mating systems of macroalgae in native habitats. Thus, it is unclear what impacts biological invasions have on different processes during the haploid-diploid life cycle. I will present part of my dissertation and post-doctoral research on haploid-diploid red seaweed genetic structure and mating systems in order to illustrate the need for a framework with which to design efficient sampling strategies. Better sampling methodology is sorely needed in order to address the impacts of different factors, ranging from the intertidal shorescape to inbreeding depression, on haploid-diploid life cycles. Click here for more information. Seminar flyer (pdf).

M. Lynch photo. Time/Date: 3:30 p.m., Tuesday, February 10
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Michael Lynch, Biology, Indiana Univ., Bloomington; NIMBioS Postdoctoral Fellows Invited Distinguished Visitor
Topic: Mutation, Drift and the Origin of Subcellular Features
Abstract: Understanding the mechanisms of evolution and the degree to which phylogenetic generalities exist requires information on the rate at which mutations arise and their effects at the molecular and phenotypic levels. Although procuring such data has been technically challenging, high-throughput genomic sequencing is rapidly expanding our knowledge in this area. Most notably, information on spontaneous mutations, now available in a wide variety of organisms, implies an inverse scaling of the mutation rate (per nucleotide site) with the effective population size of a lineage. The argument will be made that this pattern naturally arises as natural selection pushes the mutation rate down to a lower limit set by the power of random genetic drift rather than by intrinsic molecular limitations on repair mechanisms. This drift-barrier hypothesis has general implications for all aspects of evolution, including the performance of enzymes and the stability of proteins. The fundamental assumption is that as molecular adaptations become more and more refined, the room for subsequent improvement becomes diminishingly small. If this hypothesis is correct, the population-genetic environment imposes a fundamental constraint on the level of perfection that can be achieved by any molecular adaptation, and indeed all adaptations. Additional examples consistent with this hypothesis will be drawn from recent observations on the transcription error rate and on the evolution of the oligomeric states of proteins. Click here for more information. Seminar flyer (pdf).
Video icon.Watch seminar online.

S. O'Regan photo. Time/Date: 3:30 p.m., Tuesday, January 27
Location: Hallam Auditorium, Room 206, Claxton Building, 1122 Volunteer Blvd.
Speaker: Suzanne O'Regan, NIMBioS postdoctoral fellow
Topic: Detecting critical transitions in infectious disease dynamics
Abstract: Predicting abrupt shifts in state ("critical transitions") of complex systems is a key research topic in a variety of scientific domains. Small smooth changes in underlying drivers leading to a sudden change in system behavior, mathematically described as a bifurcation, is a mechanism for critical transitions of considerable interest. Bifurcations may be detectable because prior to reaching the dynamical threshold, the system may exhibit "critical slowing down." Statistical signatures of critical slowing down have been detected from temporal and spatial data in biological systems ranging from the global climate system, ecosystems, experimental microcosms and physiological systems. Anticipating infectious disease emergence and documenting progress in disease elimination are important applications for the theory of critical transitions. A key problem is the development of theory relating the dynamical processes of transmission to observable phenomena. In this talk, I consider compartmental epidemiological SIS and SIR models that are slowly forced through a critical transition. I develop expressions for the behavior of several candidate indicators during the approach to emergence or elimination. I show that moving-window estimates of the candidate indicators may be used for anticipating critical transitions in infectious disease systems. Although leading indicators of elimination were highly predictive, I found the approach to emergence to be much more difficult to detect. It is hoped that these results, which show the anticipation of critical transitions in infectious disease systems to be theoretically possible, may be used to guide the construction of online algorithms for processing surveillance data. Click here for more information. Seminar flyer (pdf).
Video icon.Watch seminar online.

NIMBioS Seminar Archive

  2014
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  2012
  2011
  2010
  2009