Events at Physics
Events During the Week of April 8th through April 15th, 2012
- No events scheduled
- Chaos & Complex Systems Seminar
- Computation and Informatics in Biology and Medicine (CIBM)
- Time: 12:05 pm
- Place: 4274 Chamberlin
- Speaker: David J. Baumler, UW Biotechnology Center
- Abstract: No other family of microorganisms has had a greater impact on human health then the Enterobacteriaceae, and these bacteria have evolved into a wide variety of commensal and human, plant, and avian pathogens. These organisms have diverged from a common ancestor ~300-500 million years ago (MYA), and little is known about ancestral metabolism. Using a paleo systems biology approach the metabolism of ancient microorganisms has been investigated through construction of metabolic models using either ancient genomic DNA (such as the Yersinia pestis genome that has been recently sequenced from human corpses that were victims of the 2nd pandemic of the black plague ~1300 A.D.) or through a comparison of 72 enterobacterial genomes of modern descendents. I will present an analysis of the ability of these ancient metabolic models to utilize 300 substrates and how some of these metabolic strategies are used in numerous human niche locations where modern-day enterobacteria cause disease. Overall this work will demonstrate that models of ancient bacteria can be used to accurately predict metabolism and to derive new targets to control human disease.
- Host: Sprott
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
- R. G. Herb Condensed Matter Seminar
- The modulated spin liquid and hidden order in URu2Si2
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Sébastien Burdin, University of Bordeaux, France
- Abstract: We have shown that near a Kondo breakdown critical point, a spin liquid with spatial modulations is likely to be formed. Unlike its uniform counterpart, we find that this occurs via a second order phase transition. The amount of entropy quenched when this ordering is manifest is of the same magnitude as for an antiferromagnet. Moreover, these two states are in direct competition with each other, and at low temperatures they are separated by a first order phase transition. This suggests that the modulated spin liquid is indeed a viable candidate for the unique phase of matter which is observed in the hidden order phase of URu2Si2. We investigate the modulated spin liquid proposal taking full account of the tetragonal-body-centered lattice structure which characterizes URu2Si2. We find that the physical quantities predicted from the model are in very good qualitative and quantitative agreement with recent experiments, including thermodynamic properties, inelastic neutron scattering, and Fermi surface measurements. We also present an overview of other f-electron compounds where similar phases have been observed.
C. Pepin, M.R. Norman, S. Burdin, and A. Ferraz, Phys. Rev. Lett. 106, 106601 (2011)
C. Thomas, S. Burdin, C. Pepin, and A. Ferraz, in preparation.
- Host: Perkins
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Observation of Reactor Antineutrino Disappearance at RENO
- Time: 2:30 pm
- Place: 4274 Chamberlin Hall
- Speaker: Soo-Bong Kim, Seoul National University
- Abstract: The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six reactors at Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 m and 1383 m, respectively, from the reactor array center. In the 229 day data-taking period of 11 August 2011 to 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). A ratio of observed to expected number of antineutrinos in the far detector is 0.920+-0.009(stat.)+-0.014(syst.). From the deficit, we find sin^2(2theta_13)=0.113+-0.013(stat.)+-0.019(syst,) based on a rate-only analysis. In this talk, its detailed analysis will be presented.
- Host: Karsten Heeger
- Astronomy Colloquium
- Plasma physics in the intracluster medium on large scales
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Aurora Simionescu, Stanford University
- Abstract: Measurements of the thermodynamic properties of the faint cluster outskirts have become possible only recently due to the unique capabilities of the Suzaku satellite. This has opened a new window for the exploration of the ongoing virialization and equilibration processes that occur as part of large-scale structure formation. I will summarize some of the most interesting conclusions regarding the physics of the intracluster medium beyond the bright cluster cores. I will focus on results from several recently finalized and ongoing Key/Large programs with the Suzaku satellite, targeting the outskirts of the Perseus, Virgo, and Coma clusters, which are the nearest, brightest clusters of galaxies, and are thus ideal targets for studying in detail the physics of the hot X-ray emitting plasma near the virial radii of these systems.
- Cosmology Journal Club
- An Informal discussion about a broad variety of arXiv papers related to Cosmology
- Time: 12:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
Please feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Le Zhang (firstname.lastname@example.org)
- Host: Peter Timbie
- Physics Department Colloquium
- Ultracold Polar Molecules
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
- Speaker: Deborah Jin, NIST & JILA
- Abstract: Gases of atoms can be cooled to temperatures close to absolute zero, where intriguing quantum behaviors such as Bose-Einstein condensation and superfluidity emerge. A new direction in experiments is to try to produce an ultracold gas of molecules, rather than atoms. In particular, polar molecules, which have strong dipole-dipole interactions, are interesting for applications ranging from quantum information to modeling condensed matter physics. I will describe experiments that produce and explore an ultracold gas of polar molecules.
- Host: Walker (Supported by WISELI - Women in Science & Engineering Leadership Institute)