THURSDAY
4/11/13

Professor Paul S. Nerenberg
W.M. Keck Science Department
Claremont McKenna, Pitzer, and Scripps Colleges

"Balancing the Energy Scale of Biomolecular Simulations"

Abstract: Molecular dynamics (MD) simulations enable us to understand the physical behavior of biological and chemical systems at the atomic scale. These simulations are now being used as a primary tool to investigate biomolecules that do not lend themselves to study with conventional structural biology techniques. One such category of biomolecules are intrinsically disordered proteins (IDPs) – proteins that do not fold to single low energy structure or contain a substantial region that does not fold – which comprise nearly half of the proteins in the human body. The structural ensembles of IDPs are dictated by small differences in energies between states, which in turn demand ever more accurate potential energy functions for the MD simulations to yield meaningful results. In this talk I will discuss recent improvements that my group has made to a popular MD force field to increase the accuracy of both protein-water and protein-protein interactions. Achieving the appropriate energetic balance between these interactions will be critical to understanding how IDPs play a role in both regular physiology and diseases such as Alzheimer's, Parkinson's, and even many cancers.

Dr. James Lamb
Assistant Professor, Department of Radiation Oncology, UCLA

"Respiratory Correlated Imaging and Lung Motion Modeling for
Radiation Therapy"

THURSDAY
4/25/13

Dr. Brian Kappus
Department of Physics & Astronomy, UCLA

"Sonoluminescence as an Ultra-Dense Microplasma"

Professor Brian Siana
Department of Physics and Astronomy, UC Riverside

"Dwarf Galaxies and the Reionization of the Universe"

Abstract: About 13 billion years ago, most of the atoms in the universe became ionized, and have remained that way ever since. The culprit is thought to be massive stars, which can produce light with sufficient energy to ionize hydrogen. However, there are two questions which must be answered: Were there enough stars in the early universe? and did a large enough fraction of the ionizing photons escape the galaxies? I will discuss our recent efforts to answer these questions with deep observations with the Keck Observatory and Hubble Space Telescope.

THURSDAY
5/9/13

Professor Christoph A. Haselwandter
Department of Physics and Astronomy, USC

"Mechanics of Bacterial Cell Membranes"

Professor Kyle Stewart
Department of Natural and Mathematical Sciences
California Baptist University

"Angular Momentum Acquisition in Milky Way Sized Galaxy Halos"

Abstract: Using high-resolution cosmological hydrodynamic simulations, we study the angular momentum acquisition of Milky Way sized galaxies, as well as the gaseous halos surrounding them. We find that "cold flow" gas accretion (gas that never shock-heats as it falls onto galaxies from the cosmic web) enters galaxy halos with roughly 70% more angular momentum than dark matter, when averaged over cosmic time. In fact, we find that all matter has more specific angular momentum when measured at first accretion, rather than averaged over the galaxy's lifetime. Combined with the fact that cold flow gas spends a relatively short time in the galaxy halo (1-2 dynamical times) before sinking to the center, this naturally explains why it has a higher spin parameter than the dark matter halo, and often forms extended "cold flow disks" of material that extend far beyond the visible portion of the galaxy. We demonstrate that the higher angular momentum associated with cold flow gas is related to the fat that it tends to be preferentially accreted along cosmic filaments.

THURSDAY
5/23/13

Professor Naveen Reddy
Department of Physics and Astronomy, UC Riverside

"TBA"

THURSDAY
5/30/13

Dr. David C. Pace
DIII-D National Fusion Facility, General Atomics

"The Fast and the Furious:
Energetic Ion Transport in Magnetic Fusion Devices"