Physics and Astronomy Calendar

All future


Thursday, February 22nd 2018
10:10 am:
Biophysics Seminar in 120 PAN
No Seminar This Week - Biophysical Society Meeting
Speaker: Avery Garon and Scott Thaller
3:35 pm:
Speaker: Erez Berg (University of Chicago)
Subject: Critical Metals: Lessons from quantum Monte Carlo studies

Critical phenomena are one of the cornerstones of classical statistical mechanics. Quantum critical points (i.e., continuous phase transitions at zero temperature) in insulating materials are relatively well understood, by analogy with classical critical points in one spatial dimension higher. In contrast, the theory of quantum critical behavior in metals is still, to a large degree, open. Such metallic critical points are believed to play an important role in the physics of several "strongly correlated" materials, such as high temperature superconductors. Fortunately, many classes of metallic quantum critical points can be simulated efficiently using quantum Monte Carlo without the notorious "sign problem", which often hinders numerical simulations of fermionic systems. I will describe some recent progress along these lines, and how it sheds new light on some of the outstanding puzzles in the field.

Faculty Host: Rafael Fernandes

Friday, February 23rd 2018
10:10 am:
Nuclear Physics Seminar in Tate 201-20
There will be no seminar this week.
12:20 pm:
Speaker: James Delles, University of Minnesota
Subject: Thermally Activated Hopping over a Barrier in a Mesoscale Permalloy System

Thermally activated hopping between energy minima in a double well system is expected to follow an Arrhenius Law. Experiments have shown that the rate of switching between two wells is proportional to the Boltzmann factor but little work has been done to probe the nature of the characteristic dwell time. A square, permalloy, mesoscale dot with an applied magnetic field can be used to create a double well system to explore the characteristic dwell time. I will show that the characteristic dwell time has an exponential dependence on the height of the barrier. There is a significant quantitative disagreement between accepted models of the dwell time and our results.

Speaker: Daniel Chung (U. Wisconsin, Madison)
Subject: Searching for Axionic Blue Isocurvature Perturbations

If the Peccei-Quinn symmetry breaking field is displaced from its minimum
during inflation, the axion isocurvature spectrum is generically strongly
blue tilted with a break transition to a flat spectrum. A test of this
scenario with the Planck and BOSS DR11 data will be presented. Encouraging
results and its implications for future probes of axions and inflationary
cosmology will be discussed.

Speaker: Attila Kovacs (SAO)
Subject: Far-infrared frontiers

The far-infrared (FIR) and (sub)millimeter bands provide us with unique views of structure formation in the Universe and the Galaxy alike. At these wavelengths we have the most adept probes of active star-formation that sample almost all of the reionized Universe (z~1--10) with essentially no bias. The Sunyayev Zel'dovich effect traces the assembly of galaxy clusters regardless of cosmological distance. Locally, in the Galaxy, FIR polarimetry probes the magnetic environments and dust properties around optically obscured young stars and cores, while FIR spectroscopy can spy on the ices in planetary disks. I will also highlight some of the ground-braking recent and upcoming instrumentation and technologies I work on to can deliver this scientific treasure trove.

Speaker: Nahyan Fancy, Department of History, DePauw University
Subject: "Did Humoral Theory Undergo any Changes in Post-Avicennan Medicine? Examples from the Commentaries of Ibn al-Nafīs (d. 1288) and his Successors in Western Eurasia"
Refreshments served at 3:15 p.m.

It has long been maintained that Galenic/Hippocratic humoral theory reigned supreme in Islamic societies from when Greek medical texts were translated into Arabic in the ninth century till the arrival of European colonial powers in the nineteenth. Historians have provided various explanations for the persistence of humoral theory in Islamic societies ranging from the (alleged) religious prohibition against dissection to a predisposition amongst medical writers towards systematizing and summarizing rather than critical inquiry. Yet, medical writers engaged critically with medical theory in their commentaries on the Canon of Medicine and the Epitome. The leading figure in this critical engagement was Ibn al-Nafīs (d. 1288). Underlying his modification of humoral theory was a sustained critique of the Galenic physiological and anatomical understanding of digestion. Consequently, the paper provides evidence for Ibn al-Nafīs conducting anatomical observations on dead animals. Moreover, the fact that his new proposals were debated and accepted by later Islamic physicians counters the prevalent assumption that his works were ignored in the later period, and thus raises the distinct possibility that these new ideas on the humors and digestion were appropriated by Renaissance physicians such as Jean Fernel.

3:35 pm:
To be announced.
4:40 pm:
To be announced.

Tuesday, February 27th 2018
3:30 pm:
Speaker: Samuel Lederer, MIT
Subject: High temperature superconductivity and strange metal behavior near a metallic quantum critical point

t has long been conjectured that quantum critical points (QCPs) are at the root of some of the most fascinating phenomena in the solid state, including the high temperature superconductivity and “strange metal” behavior of cuprate superconductors. Though much progress has been made in the theory of QCPs, those which occur in metals (and are likely relevant to the high temperature superconductors) are still poorly understood despite more than four decades of effort. Using Quantum Monte Carlo techniques, my collaborators and I have performed the first numerically exact simulations of a model which realizes a metallic QCP towards an Ising nematic ordered phase. I will discuss our results, which include numerous phenomena already observed in experiment, and comment on future avenues towards a solution of this difficult and rich problem in quantum statistical mechanics.

Faculty Host: Rafael Fernandes

Wednesday, February 28th 2018
4:30 pm:
See Joint Quantum Materials & Condensed Matter Seminar on Thursday this week only.

Thursday, March 1st 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Tanner Akkin, Associate Professor of Biomedical Engineering, University of Minnesota
Subject: Development of a Serial Optical Coherence Scanner for Visualizing and Mapping the Brain with Microscopic Resolution

The feasibility of mapping and imaging the brain with microscopic resolution is presented. A serial optical coherence scanner, which combines a polarization-sensitive optical coherence tomography and a tissue slicer, distinguishes white matter and gray matter and visualizes nerve fiber tracts that are as small as a few tens of micrometers. The technique utilizes the retardance contrast that arise due to the myelination of nerve fibers and the axis orientation contrast that determine the 2D orientation of the nerve fibers, and the technique can be adapted to measure the inclination angle of the fiber, completing the 3D orientation. This scanner could reveal biomarkers for disease onset and progression, and support development of therapeutics.

Speaker: Evan Tyler
3:35 pm:
Speaker: Sara Seager, MIT
Subject: Exoplanets
Joint Colloquium with Earth Sciences (Nier Lecture)
Speaker: Sara Seager, MIT
Subject: Mapping the Nearest Stars for habitable Worlds

Friday, March 2nd 2018
Speaker: Andrew Spray, (IBS, Daejon, Korea)
Subject: TBA
Speaker: Dr. Mateusz Ruszkowski, U. Michigan
Faculty Host: Thomas W. Jones
Speaker: Alisa Bokulich, Department of Philosophy, Boston University
Subject: "Using Models to Correct Data: Paleodiversity and the Fossil Record"
Refreshments served at 3:15 p.m.

It has long been recognized that models play a crucial role in science, and in data more specifically. However, as our philosophical understanding of theoretical models has grown, our view of data models has arguably languished. In this talk I use the case of how paleontologists are constructing data-model representations of the history of paleodiversity from the fossil record to show how our views about data models should be updated. In studying the history and evolution of life, the fossil record is a vital source of data. However, as both Lyell and Darwin recognized early on, it is a highly incomplete and biased representation. A central research program to emerge in paleontology is what D. Sepkoski has called the “generalized” (or what I prefer to call “corrected”) reading of the fossil record. Building on this historical work, I examine in detail the ways in which various models and computer simulations are being used to correct the data in paleontology today. On the basis of this research I argue for the following: First, the notion of a data model should be disentangled from the set-theoretic, ‘instantial’ view of models. Data models, like other models in science, should be understood as representations. Second, representation does not mean perfectly accurate depiction. Data models should instead be assessed as adequate-for-a-purpose. Third, the ‘purity’ of a data model is not a measure of its epistemic reliability. I conclude by drawing some parallels between data models in paleontology and data models in climate science.


Monday, March 5th 2018
12:15 pm:
Speaker: Zewei Xiong, UMN
Faculty Host: Yong-Zhong Qian

Tuesday, March 6th 2018
2:30 pm:
Speaker: Jennifer Barnes, Columbia University
Subject: TBD
Candidate for the Nucear Theory Assistant Professor position

Thursday, March 8th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Elizabeth Smith (Elias Puchner lab), School of Physics and Astronomy, University of Minnesota
Subject: Characterization of Ire1 interactions and dynamics with quantitative super-resolution microscopy

Quantitative Super-Resolution Microscopy is a powerful technique to study biological processes below the diffraction limit. In this work, we employ our intracellular calibrated Photoactivated Localization Microscopy (PALM) technique to perform quantitative molecular counting of proteins involved in the unfolded protein response (UPR). The UPR is a signaling pathway which dynamically regulates endoplasmic reticulum (ER) protein folding capacity in response to cellular stress. As is true with many signaling pathways, the spatiotemporal organization of the UPR-specific biomolecules is an inherent feature of the pathway activation and downstream response. Specifically, in response to stress, Ire1 (a bifunctional transmembrane kinase/endoribonuclease) oligomerizes and forms discrete signaling clusters which recruit and splice an mRNA encoding a transcription activator. Using PALM in conjunction with traditional fluorescence microscopy we characterize the interactions and dynamics of Ire1 at wild type expression levels in yeast cells. Specifically, we quantify the oligomeric state, of Ire1 under stressed and unstressed conditions, track the motion of Ire1 during signaling activity, and determine the sensitivity and resolution of spatial cross-correlation in a model system combining traditional and super-resolution fluorescencemicroscoy in the same protein construct (Ire1_yeGFP_mEos2). Finally we perform colocalization experiments with downstream UPR biomolecules to further characterize the role of Ire1 signaling centers in control of gene expression. This study provides insight into the spatiotemporal organization of Ire1 and its downstream partners in the signaling response of the UPR.

Speaker: Trevor Knuth and Terry Jones
3:35 pm:
Tate Grand Opening

Friday, March 9th 2018
Speaker: Stephen Martin (Northern Illinois U.)
Subject: TBA
Speaker: David Sand, U. Arizona
Faculty Host: M. Claudia Scarlata

Thursday, March 15th 2018
10:10 am:
Biophysics Seminar in 120 PAN
No Seminar This Week (Spring Break)
Speaker: No Journal Club - Spring Break
3:35 pm:
Subject: There will be no colloquium this week due to Spring Break

Friday, March 16th 2018
SPRING BREAK - No seminar this week
Speaker: No colloquium this week - Spring Break

Monday, March 19th 2018
12:15 pm:
Speaker: Liliya Williams, UMN

Wednesday, March 21st 2018
1:25 pm:
Speaker: Pablo Jarillo-Herrero, MIT
Subject: TBD
Faculty Host: Vlad Pribiag

Thursday, March 22nd 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Yahor Savich (David Thomas lab), School of Physics and Astronomy, University of Minnesota
Subject: Myosin Orientation in a Functioning Muscle Fiber With High Angular Resolution

We have measured the orientation of myosin in a muscle fiber bundle using electron paramagnetic resonance (EPR) and a bifunctional spin label (BSL), with angular resolution of a few degrees. Despite advances in cryo-EM, fluorescence, and small-angle X-ray diffraction, these techniques do not provide high-resolution structural information about myosin heads in vitro under functional conditions. A pair of (i,i+4) Cys residues were engineered on an alpha-helix in the regulatory light chain (RLC). By exchanging endogenous RLC with BSL-labeled RLC on oriented muscle fibers, we were able to resolve angular distributions in several biochemical states due to the stereospecific attachment of BSL’s two disulfide bonds. In this setup, the accurate determination of BSL’s angular coordinates allowed us to determine the orientation of individual structural elements with respect to the muscle fiber axis. Addition of ATP in the absence of Ca, relaxing the muscle, shifted the orientational distribution to a much more disordered distribution. This work is inspired by growing therapeutic interest in super-relaxed myosin state, which predicts presence of order in relaxation.

Speaker: Sharan Banagiri and Larry Rudnick
3:35 pm:
Speaker: Pablo Jarillo-Herrero (MIT)
Subject: TBD
Faculty Host: Vlad Pribiag

Friday, March 23rd 2018
10:00 am:
Speaker: Daniel Sheehy, LSU
Faculty Host: Rafael Fernandes
Speaker: Gokce Basar (U. Illinois, Chicago)
Subject: TBA
Speaker: Dr. Jordan Stone, U. Arizona
Faculty Host: Charles E. Woodward
Speaker: Rebecca Kluchin, Department of History, California State University - Sacramento
Subject: "Court-Ordered Cesarean Sections in 1980s America"
Refreshments served at 3:15 p.m.

In June 1987, Angela Carder was twenty-seven years old, married, pregnant, and in remission from cancer. Twenty-five weeks into her pregnancy, she learned that the disease had returned and metastasized in her right lung. Her prognosis was terminal and her condition deteriorated rapidly. When George Washington University Hospital administrators learned that Carder was dying and lacked a plan to save her fetus, they initiated an emergency legal hearing to determine their responsibility to her pregnancy. A judge ordered Carder to undergo an immediate cesarean section. The baby lived two hours. Carder died two days later.

Carder’s parents appealed the decision and in 1990, the District of Columbia Court of Appeals ruled in their favor. The Carder case became national news and entered popular culture when the popular television show LA Law ran an episode based on it. But the Carder case did not occur in a vacuum; in fact, one month before Carder died, the New England Journal of Medicine published an article that revealed twenty-one prior attempts of court-ordered cesarean sections, eighteen of which were successful. Eighty-one percent of patients forced to undergo surgery were women of color and twenty-four percent were non-English speakers. The media attention granted to the Carder case obscured the other forced cesareans and erased women of color from the story. This paper reveals this hidden reproductive history, places it in the context of other reproductive abuses, and locates women of color at the center of the story instead of on the periphery. It argues that court-ordered cesarean sections simultaneously continued the long history of reproductive abuses directed at women of color and represented a new form of abuse specific to the post-Roe era and the politics of legal abortion.


Tuesday, March 27th 2018
2:30 pm:
Speaker: Vladimir Skokov, Brookhaven National Laboratory
Subject: TBD
Candidate for the Nucear Theory Assistant Professor position
Speaker: Michael Fogler, University of California, San Diego
Faculty Host: Boris Shklovskii

Wednesday, March 28th 2018
1:30 pm:
Speaker: Paul Canfield (Iowa State)
Subject: TBD
Faculty Host: Martin Greven
3:30 pm:
Space Physics Seminar in Physics 201-20
Speaker: Barry Mauk, APL
Subject: TBD
Faculty Host: Robert Lysak

Thursday, March 29th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Casim Sarkar, Professor of Biomedical Engineering, University of Minnesota
Subject: Integrating experimental and computational approaches to elucidate mechanisms of binding in multivalent proteins

Multivalent proteins are ubiquitous in nature and can provide unique, exploitable properties in therapeutic applications such as increased affinity or multi-target specificity. Despite the importance of these proteins in fundamental and applied biomedical research, mechanistic quantitative descriptions of their binding kinetics are limited. We have considered such multivalent protein-protein interactions to be driven by three key variables: the binding affinity of individual monomer units, the linker length/structure between the monomers, and the overall valency of each multivalent protein. Using model synthetic proteins in which all three of these variables can be independently tuned, we have performed surface plasmon resonance experiments to quantify the kinetics of association and dissociation as a function of affinity, linker, and valency. In parallel, we developed a mechanistic model based on mass-action kinetics that explictly enumerates all possible microstates that participate in the binding reaction. Integration of these quantitative experimental and computational approaches has elucidated a number of interesting findings, including the role of valency in generating non-canonical reaction kinetics, that will be discussed. Our approach should enable better understanding of dynamic behaviors in natural multivalent proteins and lead to more rational optimization of multivalent therapeutics.

Speaker: Brian O'Neill
3:35 pm:
Speaker: Barry Mauk, APL
Subject: New perspectives on Jupiter’s novel space environment and aurora from NASA’s Juno mission

B. H. Mauk, The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA (Barry.Mauk@jhuapl.edu)

Jupiter’s uniquely powerful auroras are thought to be symptoms of Jupiter’s attempt to spin up its space environment and shed angular moment (albeit minuscule amounts). The processes involved connect together such disparate phenomena as the volcanoes of Jupiter’s moon Io and the Jupiter-unique synchrotron emissions imaged from ground radio telescopes at Earth. While the power sources for auroral processes at Earth and Jupiter are known to be very different, it has been expected that the processes that convert that power to auroral emissions would be very similar. NASA’s Juno mission, now in a polar orbit at Jupiter, is dramatically altering this view about how Jupiter’s space environment operates. Auroral processes are much more energetic than expected, generating beams of electrons with multiple MeV energies and with directional intensities that can be more intense than the electrons within Jupiter’s radiation belts. The most intense auroral emissions appear to be generated by processes that have no precedent within Earth auroral processes. And, the auroral generation processes are poorly correlated, unexpectedly, with any large-scale electric currents thought necessary to regulate the interactions between Jupiter’s spinning atmosphere and space environment. These and other findings are discussed, along with presentation of Juno’s broader mission and discoveries.

Faculty Host: Robert Lysak

Friday, March 30th 2018
Speaker: Hooman Davoudiasl (Brookhaven)
Subject: TBA
Speaker: Lou Stolger, Space Telescope
Speaker: Susan Rensing, Department of Women's & Gender Studies, University of Wisconsin - Oshkosh
Subject: HSTM Alumni Lecture - "‘A Coldly Scientific Venture’: Unwed Mothers and the Eugenic Baby Panic"
Refreshments served at 3:15 p.m.

In January of 1928, the New York World set off a firestorm of controversy with a front page story about a wealthy widow, Grace Burnham, who had “mated lovelessly” as a eugenic experiment. Newspapers rushed to seek out stories of other women who were conceiving eugenic babies by selecting a man purely for reproduction, not for marriage. Unlike the wholesome eugenic babies that won ribbons in Better Baby Contests at state fairs, these eugenic babies were portrayed as potential Frankensteins--creations of science run amok. Moral condemnation raged in editorials across the nation as experts weighed in with their opinions about this alarming trend. This talk will use the eugenic baby panic as a cultural lens to examine fears about science bereft of morality in the late 1920s and early 1930s.


Monday, April 2nd 2018
12:15 pm:
Speaker: Matt Gomer, UMN
Faculty Host: Liliya L.R. Williams

Wednesday, April 4th 2018
1:25 pm:
Speaker: Sung-Sik Lee (Perimeter Institute)
Subject: TBD
Faculty Host: Andrey Chubukov

Thursday, April 5th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: James M. Carothers, Department of Bioengineering, University of Wisconsin

Metabolite-responsive RNA regulators that react to changing conditions through molecular interactions are widespread in biology. In many of these systems, kinetic control mechanisms coordinate co-transcriptional RNA folding with metabolite binding and enable outputs that are highly-sensitive and highly-selective to target ligands. Although synthetic riboswitches exhibiting kinetic control have been identified by chance, it has not been possible to intentionally engineer kinetically-controlled RNA aptamer devices. Consequently, kinetic control mechanisms that could otherwise be exploited to overcome functional limits imposed by the thermodynamics of molecular recognition have remained beyond reach. We recently developed a novel approach for multi-state, co-transcriptional RNA folding design that has allowed us to engineer kinetically-controlled RNA aptamer ribosensors. In this architecture, in vitro selected RNA aptamers are coupled through a timer domain to a toehold-mediated strand displacement (TMSD) actuator such that co-transcriptional ligand-binding generates fluorescence from DNA gates through TMSD. We have shown that ribosensors can be transcribed in situ and used to analyze metabolic production directly from engineered microbial cultures, establishing a new class of cell-free biosensors. We found that kinetically-controlled ribosensors exhibited 5-10 fold greater ligand sensitivity than a thermodynamically-controlled device. And, we further demonstrated that a second aptamer, promiscuous for aromatic amino acid binding, could be assembled into kinetic ribosensors with 45-fold improvements in ligand selectivity. I will present these results and discuss the broader implications of this work for engineering RNA aptamer devices and overcoming thermodynamic constraints on molecular recognition through the design of kinetically-controlled responses.

Faculty Host: Vincent Noireaux
Speaker: Nathan Eggen
3:35 pm:
Speaker: Alessandra Corsi, Texas Tech
Subject: TBD
Faculty Host: Vuk Mandic

Friday, April 6th 2018
Speaker: TBA
Subject: TBA
Speaker: No colloquium this week.
Speaker: Stuart Glennan, Department of Philosophy, Butler University
Subject: “Compositional Minimalism”
Refreshments served at 3:15 p.m.

In her paper, “Causality and Determination,” Elizabeth Anscombe advanced an approach to causation that Peter Godfrey-Smith has dubbed “causal minimalism.” In this approach, causation is not one thing, but many. Causal relations depend upon a heterogeneous set of specific activities – like bonding, pushing, tearing or fighting. My aim in this talk is to pursue a related strategy for compositional relations between parts and wholes – whether these be between atoms and molecules, tissues and organs, or children and families. Composition, like causation, is not one thing, but many – largely because parts are bound into wholes by causal relations.


Monday, April 9th 2018
12:15 pm:
Speaker: Jose Diego, Consejo Superior de Investigaciones Cientificas, CSIC
Faculty Host: Patrick Kelly

Wednesday, April 11th 2018
1:25 pm:
Speaker: Xiaojia Wang (University of Minnesota)
Subject: TBD
Faculty Host: Paul Crowell

Thursday, April 12th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Aaron Engelhart, Department of Genetics, Cell Biology, and Development, University of Minnesota
Speaker: Karl Young
3:35 pm:
Speaker: Doug Glenzinski, Fermilab
Subject: TBD
Faculty Host: Dan Cronin-Hennessy

Friday, April 13th 2018
Speaker: Kristian Jensen (San Francisco State U.)
Subject: TBA
Speaker: T. Rivera-Thorsen, Institute of Theoretical Astrophysics
Faculty Host: M. Claudia Scarlata
Speaker: Lawrence Principe, Department of History of Science & Technology, Johns Hopkins University
Subject: "Wilhelm Homberg’s Laboratories and Instruments: Doing Chymistry in Early Modern France"
Refreshments served at 3:15 p.m.

One of chemistry’s chief characteristics is its union of head and hand, theory and practice, and the subsequent need for workspaces and instruments doing chemistry practically. Wilhelm Homberg (1653-1715), the chief chymist of the Parisian Académie Royale des Sciences, worked in many different spaces over the course of his remarkable career. Starting in 1702, he worked in what was called at the time “the most magnificent laboratory that chymistry had ever known”--a workspace specially-built for him in the Royal Palace by his patron (and collaborator) Philippe II, duc d’Orléans, the future Regent of France. Philippe also outfitted this laboratory with the most extraordinary--and costly--scientific instrument of time, and Homberg enjoyed exclusive access to it. This talk examines the various workspaces Homberg used, highlighting the results that he achieved and their relation to spaces and instruments, the role of patronage, and the changing nature of chymistry in the period.


Monday, April 16th 2018
12:15 pm:
Speaker: Hugh Dickinson, UMN

Wednesday, April 18th 2018
7:00 pm:
Kaufmanis Public Lecture in McNamara Alumni Center
Speaker: Victoria Kaspi, McGill University
Subject: Astronomy's Newest Extragalactic Mystery: Fast Radio Bursts!

In 2007, astronomers discovered a new mysterious cosmic phenomenon: Fast Radio Bursts. These events consist of short, intense blasts of radio waves arriving from far outside our Milky Way galaxy. Their origin is unknown, however Fast Radio Bursts appear ubiquitous in our Universe, with roughly 1000 arriving every day over the full sky. I will discuss the Fast Radio Burst mystery and what is presently known about it, and describe a revolutionary new radio telescope being built in Canada that will soon enable astronomers worldwide to make major progress in our understanding of the FRB puzzle.


Thursday, April 19th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Ashim Rai, (postdoc in Shiv’s lab) Department of Genetics, Cell Biology and Development, University of Minnesota
Subject: Biophysical regulation of myosin VI motility by cargo adaptor proteins

: Cargo transport by motor proteins organizes the cell interior. On cellular cargoes, the binding of motor proteins is mediated by cargo adaptor proteins. Initially thought of as passive scaffolds for motor proteins, cargo adaptor proteins have recently been shown to directly affect motor function through structural studies. However, a biophysical mechanism of cargo adaptor-mediated regulation of motor activity is still lacking. In this study, we have tried to address this problem in the context of the minus-end directed actin motor, Myosin VI. Through direct measurements of adapter-mediated changes in myosin VI motility, conformation and dimerization, we have tried to establish a structure-function relationship between myosin VI and its cargo adaptor proteins. We find that binding to cargo adaptor has a potentiating effect on myosin VI velocity and processivity which is mediated through a combination of auto inhibition release, lever arm extension and dimerization of the myosin VI motor.

Speaker: John Phillips
3:35 pm:
Speaker: Victoria Kaspi, McGill University.
Subject: TBD
Faculty Host: Andrey Chubukov

Friday, April 20th 2018
Speaker: Nobuchika Okada (U. Alabama)
Subject: TBA
Speaker: No colloquium - See info for the Kaufmanis Public Lecture on the 18th
Speaker: Roberta Humphreys, Minnesota Institute for Astrophysics, University of Minnesota
Subject: "Margaret Burbidge, and the Annie Jump Cannon Award or How I Met Vera Rubin -- a Personal and Scientific Recollection"
Refreshments served at 3:15 p.m.

Monday, April 23rd 2018
12:15 pm:
Speaker: Qi Wen, UMN
Faculty Host: Shaul Hanany

Thursday, April 26th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Gianluigi Veglia, Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota
Speaker: Sourabh Chauhan
3:35 pm:
Speaker: John Bush, MIT
Subject: TBD
Faculty Host: J. Woods Halley

Friday, April 27th 2018
Speaker: Mustafa Amin (Rice U)
Subject: TBA
Speaker: Dr. Christian Veillet, Large Binocula Telescope Observatory (LBTO)
Faculty Host: Charles E. Woodward
Speaker: Richard Samuels, Department of Philosophy, The Ohio State University
Subject: "How to Acquire Number Concepts: A New Puzzle (With Stewart Shapiro and Eric Snyder)"
Refreshments served at 3:15 p.m.

Philosophers and psychologists have long been interested in how human beings learn mathematical concepts in general, and natural number concepts, in particular. Efforts to explain how such concepts are learned, however, have resulted in a number of puzzles and problems, which have led some to conclude that these concepts cannot be learned. In this talk, we first sketch some of the more important of these puzzles, and then articulate a new one that rests upon an apparent tension between two of the best empirical probes into our natural number concepts – linguistic semantics and developmental psychology. On the face of it, the dominant views in these respective fields are in tension with each other, so that if the semanticists are right, then our best accounts of how natural number concepts are learned must be wrong. Having set out this puzzle in some detail, we argue that a structuralist conception of the naturals offers a partial resolution of this apparent tension.


Monday, April 30th 2018
12:15 pm:
Faculty Host: M. Claudia Scarlata

Thursday, May 3rd 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Ibrahim Cisse, Department of Physics, Massachusetts Institute of Technology
3:35 pm:
Speaker: Jeffrey Bub, Maryland
Subject: TBD
Faculty Host: Michel Janssen

Friday, May 4th 2018
Friday, May 4 - Sunday, May 6 2018
Faculty Host: Alex Kamenev
Speaker: Yanou Cui (U. California, Riverside)
Subject: Cosmic Archaeology with Gravitational Waves from Cosmic Strings

Cosmic strings are generic cosmological predictions of many extensions
of the Standard Model of particle physics, such as a U(1) symmetry breaking phase transition in the early universe or remnants of superstring theory. Unlike other topological defects, cosmic strings can reach a scaling regime that maintains a small fixed fraction of the total energy density of the universe from a very early epoch until today. If present, they will oscillate and generate gravitational waves with a frequency spectrum that imprints the dominant sources of total cosmic energy density throughout the history of the universe. In this talk I will demonstrate that current and future gravitational wave detectors, such as LIGO and LISA, could be capable of measuring the frequency spectrum of gravitational waves from cosmic strings and discerning the energy composition of the universe at times well before primordial nucleosynthesis and the cosmic microwave background where standard cosmology has yet to be tested. This work establishes a benchmark case that gravitational waves may provide an unprecedented, powerful tool for probing the evolutionary history of the very early universe.

Speaker: Dr. Silva Protoppa, U. Maryland
Faculty Host: Charles E. Woodward

Saturday, May 5th 2018
Friday, May 4 - Sunday, May 6 2018
Faculty Host: Alex Kamenev

Sunday, May 6th 2018
Friday, May 4 - Sunday, May 6 2018
Faculty Host: Alex Kamenev

Thursday, May 10th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker:  Hyun Youk, Kavli Institute of Nanoscience, TU Delft, Netherlands

Wednesday, May 16th 2018
Wednesday, May 16 - Saturday, May 19 2018
Faculty Host: Andrey Chubukov

Thursday, May 17th 2018
Wednesday, May 16 - Saturday, May 19 2018
Faculty Host: Andrey Chubukov

Friday, May 18th 2018
Wednesday, May 16 - Saturday, May 19 2018
Faculty Host: Andrey Chubukov

Saturday, May 19th 2018
Wednesday, May 16 - Saturday, May 19 2018
Faculty Host: Andrey Chubukov

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