Events at Physics |
Events During the Week of March 23rd through March 30th, 2008
Monday, March 24th, 2008
- Plasma Physics (Physics/ECE/NE 922) Seminar
- LiWall Fusion (LiWF) and its Three Step Program Toward a Reactor Development Facility
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Leonid Zakharov, Princeton Plasma Physics Laboratory, Princeton University
- Medical Physics Seminar
- Title to be announced
- Time: 4:00 pm
- Place: 1345 Health Science Learning Center (refreshments will be served)
- Speaker: Shuai Leng, student of Dr. Guang-Hong Chen, Assistant Professor of Medical Physics and Radiology, UW-School of Medicine and Public Health
- High Energy Seminar
- GammeV: Gamma to milli-eV Particle Search
- Time: 4:00 pm
- Place: 4274 Chamberlin (Coffee and Cookies at 3:30 pm)
- Speaker: William Wester, Fermi National Accelerator Laboratory
Tuesday, March 25th, 2008
- Chaos & Complex Systems Seminar
- Computational constraints in Hebbian learning: relationship to epileptogenesis and other neurological disorders
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall
- Speaker: David Hsu, Neurology
- Abstract: The ability of the brain to absorb and incorporate within itself new ideas implies that it is a metastable system. It must continually change and yet not devolve into randomness. How does it do this, and what are the consequences? Brain activity can be represented in terms of a large collection of excitable bodies that possess both spontaneous activity and that can stimulate other bodies to become excited. I discuss a simple computer model of such a system and study (1) what is necessary for such a system to learn, and (2) what is necessary for it to maintain itself in a state capable of further learning. It turns out that the highest performing brain models that are able to maintain stable learning also show self-organized criticality. Unfortunately, the homeostatic constraints that maintain optimal brain performance also predispose the brain toward neurological disease. The relationship to epilepsy is presented, and an approach to its cure is proposed.
- Astronomy Colloquium
- Smith's Cloud: The Most Interesting Hydrogen Cloud in the Local Universe
- Time: 3:45 pm
- Place: 6515 Sterling Hall (coffee at 3:30 pm in 6521 Sterling)
- Speaker: Jay Lockman, NRAO
- Abstract: In the first part of the talk I will review the capabilities of the new Green Bank 100 meter diameter radio telescope (GBT) and briefly discuss some of the scientific programs to which it has contributed. The main part of the talk will be about Smith's Cloud. This hydrogen cloud has been known since 1963 and is usually classified as a high-velocity cloud, but only recently has its nature become clear through observations with the GBT. It is a coherent mass of gas more than 3x1 kpc in extent, contains more than a million solar masses of hydrogen, and appears to be on a trajectory to cross the Galactic plane in 20-40 Myr. It is now interacting with the gaseous halo of the Galaxy and is in the process of breaking up. It may be the prototype of a gas cloud accreting onto the Milky Way and bringing fresh gas to fuel star formation.
- Host: Snezana Stanimirovic
Wednesday, March 26th, 2008
- Informal Seminar
- If the WIMP will not come to the neutron star; the neutron star will go to the WIMP
- Time: 4:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Hakki B. Ogelman, UW-Madison
Thursday, March 27th, 2008
- R. G. Herb Condensed Matter Seminar
- Title to be announced
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Wolfram Brenig, Technishce Universitat Branuschweig
- Host: Chubukov
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Particle Acceleration in Supernova Remnant Shocks
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Pat Slane, Harvard
Friday, March 28th, 2008
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Scale of Left-Right Symmetry from CP-violating Observables
- Time: 2:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Xiangdong Ji (TBC), University of Maryland
- Physics Department Colloquium
- Particle Acceleration and Explosive Energy Release by the Sun
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Bob Lin, University of California - Berkeley
- Abstract: The Sun is the most energetic natural particle accelerator in the solar system, generating ions up to 10s of GeV and electrons to 100s of MeV, in both large solar flares and fast coronal mass ejections. Large solar flares are the most powerful explosions in the solar system, releasing up to ~1032 ergs in 100-1000 s, with >~10-50% of this energy in accelerated particles. I will present observations from the RHESSI (Ramaty High Resolution Solar Spectroscopic Imager) spacecraft of the hard X-ray (HXR)/gamma-ray continuum and gamma-ray line emission produced by the accelerated electrons and ions, respectively, showing that the process of magnetic reconnection is key for flare energy release and particle acceleration. I will also present direct in situ space observations showing that magnetic reconnection and related particle acceleration also occurs in the Earth's magnetosphere, at Mars, in the solar wind, and, very likely, in cosmic explosions. These measurements, together with recent results from laboratory plasma experiments, theory, and simulations, have led to significant progress in understanding these ubiquitous phenomena.
- Host: Prager