Past Events

  • Math-Bio seminar: "Assessing the relationship of ancient samples to modern populations and to each other"

    318 Carolyn Lynch Laboratory

    Joshua Schraiber, Temple University

    When ancient samples are sequenced, one of the first questions asked is how those samples relate to modern populations and to each other. Commonly, this is assessed using methods such as Structure or Admixture, which model individuals as mixtures of latent "ancestry components". If an ancient individual is found to not carry similar ancestry components to a modern individual, that sample is considered to be not directly related to the modern individual.

  • Math-Bio seminar: "Bayesian inference of evolutionary divergence with genomic data under diverse demographic models"

    318 Carolyn Lynch Laboratory

    Yujin Chung, Temple University

    In the study of diverging populations and species, a common goal is to disentangle the conflicting signals of prolonged genetic drift (elevating divergence) and gene exchange (removing it). In this talk, I present a new Bayesian method for estimating demographic history using population genomic samples. Several key innovations are introduced that allow the study of diverse models within an Isolation with Migration framework.

  • High Energy Seminar: "TBA"

    David Rittenhouse Laboratory, 2N36

    Paolo Creminelli (ICTP)

  • Special Seminar: "Steric association of bent molecules into chiral oligomeric chains: the slinky-like structure of the twist-bend nematic phase"

    David Rittenhouse Laboratory, A4

    Noel Clark, University of Colorado

  • Astro Seminar: "The New Ly-alpha Power Spectrum Measurements and constraints on WDM"

    David Rittenhouse Laboratory, A4

    Vid Irsic (University of Washington)

    With the X-Shooter XQ-100 Legacy survey, 100 QSO measurements at intermediate resolutions were available to measure the Lyman-alpha power spectrum in the similar redshift range to SDSS (z=3 - 4.2), but to smaller scales (k_max ~ 6 h/Mpc). I will present these new results and comment on the data-analysis procedure. In the second part of the talk I will focus on using these new data (along with high-resolution high-redshift data) to put constraints on the cosmological and astrophysical parameters, and to review the constraints on the mass of a WDM particle as a DM candidate.

  • Experimental Particle Physics: "Search for Supersymmetry in Events with Four or More Leptons at ATLAS "

    David Rittenhouse Laboratory, 4C8

    Matthew Klein (Columbia University)

  • Math-Bio seminar: "Controlling the rate of false discoveries in tandem mass spectrum identifications"

    318 Carolyn Lynch Laboratory

    Uri Keich, University of Sydney

    A typical shotgun proteomics experiment produces thousands of tandem mass spectra, each of which can be tentatively assigned a corresponding peptide by using a database search procedure that looks for a peptide-spectrum match (PSM) that optimizes the score assigned to a matched pair. Some of the resulting PSMs will be correct while others will be false, and we have no way to verify which is which. The statistical problem we face is of controlling the false discovery rate (FDR), or the expected proportion of false PSMs among all reported pairings.

  • High Energy Seminar: "Shaving off Black Hole Soft Hair"

    David Rittenhouse Laboratory, 2N36

    Massimo Porrati (New York University)

    After recalling a definition of a black hole "hair" we explain why the only interesting hairs are those that are also remnants. Next, we will examine a recent proposal by Hawking, Perry and Strominger, who suggest that soft photons and soft gravitons can be regarded as black hole hairs that may be relevant to the black hole information paradox.

  • Condensed Matter seminar: "Putting Patterns on Spheres: Pollen Grains and Cholesteric Liquid Crystal Shells"

    David Rittenhouse Laboratory, A4

    Max Lavrentovich, University of Pennsylvania

    Insect egg shells, mite carapaces,  pollen grain surfaces, and many other biological materials exhibit intricate surface patterns including stripes, spikes, pores, and ridges.

  • Math-Bio seminar: "Changes in local chromatin structure during homology search: effects of local contacts on search time"

    318 Carolyn Lynch Laboratory

    Assaf Amitai, M.I.T.

    Double-strand break (DSB) repair by homologous recombination (HR) requires an efficient and timely search for a homologous template. We developed a statistical method of analysis based on single-particle trajectory data which allows us to extract forces acting on chromatin at DSBs. We can differentiate between extrinsic forces from the actin cytoskeleton and intrinsic alterations on the nucleosomal level at the cleaved MAT locus in budding yeast.