Events at Physics |
Events During the Week of February 1st through February 8th, 2009
Monday, February 2nd, 2009
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Recent 2-Fluid Simulation Results on Internal Kink and Tearing
- Time: 12:05 pm
- Place: 3345 Engineering Hall
- Speaker: Prof. Carl Sovinec, UW-Madison, Dept of EP
- Plasma Theory Seminar
- Dissipation Range of MHD Turbulence
- Time: 4:00 pm - 5:00 pm
- Place: 514 ERB
- Speaker: Paul Terry, UW-Madison, Dept of Physics/Plasma
Tuesday, February 3rd, 2009
- Special Plasma Seminar
- "Tests of Collision Operators Using Laboratory Measurements of Shear Alfven Wave Dispersion and Damping
- Time: 12:00 pm - 1:15 pm
- Place: 5280 Chamberlin Hall
- Speaker: Derek Thuecks, University of Iowa
- Chaos & Complex Systems Seminar
- Norepinephrine, Networks, and Behavior: One aproach to Systems Neuroscience
- Time: 12:05 pm
- Place: 4274 Chamberlin
- Speaker: David Devilbiss, UW Department of Psychology
- Abstract: Norepinephrine, an endogenous chemical within the brain modulates target neuron excitability. This neuromodulator permits global state changes of the brain (from sleep to waking) as well as participating in brain functions including cognitive processes such as attention and dysfunctions such as attention deficit hyperactivity disorder and depression. This talk will describe the nonlinear nature of this neuromodulators effects on target neuron discharge properties, the summation of its effects on many individual neurons to alter the dynamics of neuronal populations, and the resultant effects on animal behaviors.
- Astronomy Colloquium
- The Incredible Omega Centauri- A Laboratory for Chemical Enrichment
- Time: 3:45 pm
- Place: 6515 Sterling Hall
- Speaker: Caty Pilachowski, Univ of Indiana-Bloomington
- Abstract: The globular cluster Omega Centauri continues to surprise us - a dispersion in metallicity, multiple main sequences, and even a black hole. As a laboratory for chemical enrichment, Omega Centauri is unparalled. Detailed studies of the composition of a large sample of giant stars in the cluster reveal the complex nature of chemical enrichment that occurred. Clues to the history of the cluster can be found in the changing abundances of light and heavy elements with metallicity. Comparison to other bulge, disk, and dwarf spheroidal stellar populations showing evidence of chemical enrichment suggests that Omega Centauri's path has been unique.
- Host: Emily Freeland Grad Student (WOWSA)
Wednesday, February 4th, 2009
- No events scheduled
Thursday, February 5th, 2009
- R. G. Herb Condensed Matter Seminar
- Probing Electron Energy Distribution in Carbon Nanotubes
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Yung-Fu Chen, Frederick Seitz Materials Research Lab, UIUC
- Abstract: Carbon nanotubes are considered model one-dimensional systems, and their electronic transport is strongly affected by electron-electron (e-e) interactions. Measurements of the non-equilibrium electron energy distribution function in nanotubes may directly determine electron energy relaxation rates, which may also tell us e-e scattering rates and therefore something about e-e interactions in nanotubes. We developed techniques to perform tunneling spectroscopy on nanotubes using non-invasive superconducting probes, which allows us to measure the shape of the electron energy distribution locally in nanotubes that have bias voltages applied between their ends to drive the electrons out of equilibrium. We find that at low temperatures electrons in nanotubes maintain their energy distribution across a few microns channel length. Surprisingly, the energy relaxation rate sometimes grows substantially when the temperature is raised to only 1.5 K.
- Host: Robert McDermott
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Cosmology and the LHC
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Carlos E M Wagner, Argonne National Laboratory & University of Chicago
- Abstract: The LHC is expected to shed light on the physics behind the mechanism of electroweak symmetry breaking, associated with the generation of mass of all known elementary particles. There are good reasons to think that the same physics is responsible for the origin of dark matter and, perhaps, of the observable matter-antimatter asymmetry. In this talk I will summarize the arguments that support the above statements and provide a few examples of the interplay between cosmology and collider physics at the LHC.
- Host: M J Ramsey-Musolf
- Special Plasma Seminar
- "Ion Current Estimations in the Irvine Field Reversed Configuration:
- Time: 4:00 pm - 5:15 pm
- Place: 5280 Chamberlin Hall
- Speaker: Wayne Harris, University of California/Irvine
Friday, February 6th, 2009
- Physics Department Colloquium
- Ingersoll Lecture
- Exploiting protein-crystal interactions to build switches, throttles and brakes: what shells, bones and kidney stones can teach us about managing CO2
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee and cookies at 3:30 pm)
- Speaker: James J. De Yoreo, Molecular Foundry, LBNL
- Abstract: Coal is the major source of energy for electrical generation across the globe. In the United States, it provides about a third of our electricity, while in China, where coal accounts for over 75% of electrical generation, a new coal-burning power plant comes on line every week. But coal is amongst the most intense sources of greenhouse gases, producing nearly three tons of CO2 for every ton of coal consumed and contributing 40% of all anthropogenic CO2. Moreover, coal is an essential constituent in about 65% of all steel production. With oil nearing peak production, nuclear energy likely to be slow in coming on line, solar and other renewables still in their infancy, and no obvious substitute for coking steel, the world will continue to rely on coal for decades to come. So what are we going to do with all of that carbon? The answer may lie in the workings of tiny marine organisms, which transform CO2 into structural materials made of calcium carbonate through a process known as biomineralization. Similar processes direct the growth of bones and teeth and prevent formation of kidney stones. The interaction of proteins with inorganic constituents is a defining feature of biomineralization. An understanding of the structural relationships, adsorption dynamics and resulting control mechanisms may one day enable us to mimic the process. In this talk I will present results from in situ AFM investigations of peptide and protein interactions with growing crystal surfaces in which cantilevers designed to maximize tip-sharpness while minimizing contact force were used to obtain true single-molecule resolution. Analysis of the results reveals how the slow adsorption dynamics, strong electrostatic interactions and tendency towards aggregation peculiar to macromolecules lead to unexpected and varied controls on crystal growth. For example, when the timescales for peptide adsorption and step advancement overlap, minute changes in growth conditions lead to rapid switching between two stable states of growth. Physical models based on the thermodynamics of steps on crystal surfaces and the dynamics of peptide adsorption provide an understanding of the observed behavior. The findings suggest strategies for sequestering CO2 by directing the timing and rate of carbonate formation in subsurface reservoirs through the use of protein-like molecules as "switches, throttles and brakes".
- Host: Gilbert