1. Monday, Jan. 28, 2002

Dr. Mukta Singh-Zocchi, Department of Physics and Astronomy, UCLA
Title: Nanometer-Scale Measurements of Conformational Changes in Proteins and DNA
Abstract:  The ability to undergo functional conformational changes distinguishes biological macromolecules (proteins, DNA) from inanimate matter. Recently it has been possible to observe some of these molecular processes directly, through single molecule experiments. After a brief introduction to this field I will describe two micro-mechanical experiments with which we obtain micron scale measurements of conformations in real time.

In the first experiment we show that globular proteins under large (~ 1-2 nm) deformations maintain a non-zero shear modulus and display a slow dynamics similar to "creep" in solids.

In the second experiment we detect directly the shortening of DNA oligomers upon hybridization with a complementary strand.

2. Monday, Feb. 11, 2002 Prof. Elizabeth Potter, Alice Andrews Quigley Professor of Women's Studies,  Women's Studies Program, Mills College
Title:"Gender Politics and Good Science"
Abstract:
How can we say that Robert Boyle's work leading to the Ideal Gas Law was influenced by class and gender considerations and yet maintain that this was excellent scientific work?

How can a scientist like Boyle both engage in good work based on careful, reproducible experiments and make scientific choices in the light of the gender and class politics of the time?

We will explore these and related questions.

3. Monday, Feb. 25, 2002

Dr. Zhigang Gong, Cenix Incorporated,
Title: "Helioseismology and physics inside the sun"
Abstract: Being the closest star from earth, the sun provides us a unique opportunity to study the physical characteristics of stellar material in both space and time domain. By investigating the behavior of millions of observed p-mode oscillation modes, helioseismology further extends our knowledge from the surface of the sun to the solar interior. Combining the information from helioseismology and the  equation of state of the solar material, we find a new method to detect the heavy element abundance down to the solar convection zone. Such information also helps us to understand the physical processes that cannot be tested in terrestrial laboratories.

4. Monday, Mar. 4, 2002

Mr. Rajesh Ojha,  Department of Physics and Astronomy, UCLA
Title: "An Application of Statistical Mechanics to an Athermal System"
Abstract: It is well-known that granular materials are far too massive to be affected by room-temperature thermal fluctuations.  To induce motion in a granular pile, one must provide some sufficient external force.  The grains then interact only via hard-core repulsions and frictional forces which dissipate energy from the system.  The grains therefore do not explore phase-space states of varying energy in the same manner as fluid molecules, and statistical mechanics appears to be unavailable for use in describing the motion of granular systems.  In this talk, I will discuss a simple granular system for which we find that a statistical mechanics description is truly applicable.

5. Monday, Mar. 11, 2002

Prof. Lillian McDermott, Department of Physics, University of Washington
Title: "Discipline-based research on learning and teaching:  The key to more effective instruction in physics and other sciences"
Abstract: The difference between what is taught and what is learned is often greater than most instructors recognize.  The discrepancy is documented through research in which we examined how well undergraduate and graduate students and K-12 teachers understand some basic physical concepts.  Examples are used to illustrate how discipline-based education research can improve student learning.  The perspective that teaching is a science as well as an art has strong implications for undergraduate instruction, for K-12 teacher preparation, and for the professional development of graduate students for their role as future faculty.  Although the context is physics, analogies can readily be made to other sciences and mathematics.  Research on learning and teaching conducted by scientists in science departments can provide the key to setting realistic standards, to helping students meet expectations, and to assessing the extent to which real learning takes place.

6. Monday, Apr. 8, 2002

Prof. Richard Haskel, Department of Physics, Harvey Mudd College.
Title: "Optical Coherence Tomography (OCT): A Non-invasive Imaging Technique for Biological Tissue"
Abstract: OCT arose about 10 years ago to meet an imaging need in ophthalmology.  It was quickly adopted as a non-invasive probe of skin, and because the instrument is fiber-based, it has been used through an endoscope to examine the linings of the esophagus and the GI tract.  Recently OCT has been performed through a catheter to aid in the identification and removal of occlusions in arteries.  It also serves as an ideal research tool for studying dynamic processes in the early development of plants and animals.

I will describe the physical principles of OCT, including its reliance upon a near-infrared light source with a short coherence length, and its sensitivity to Bose-Einstein photon bunching.  I will also describe the motion-sensitive technique of Doppler OCT that is used to measure blood flow in small vessels.  As an illustrative example drawn from our own lab, time-lapse movies will be shown of gastrulation in a frog, the first major developmental event in the life of a vertebrate.

7. Monday, Apr. 15, 2002

Prof. Peter Taborek, Department of Physics, UC Irvine
Title: "Wetting , Prewetting and Sticky Superfluids"
Abstract: Superfluid helium films have played an important role as a model system for studies of phase transitions. Recently it has become clear that helium films on  alkali metal substrates have a completely different phenomenology from helium on any conventional substrate such as copper, silicon, or mica. Helium on alkali metal substrates displays wetting and prewetting transitions, and it is possible to form superfluid drops, which will be shown in a video. The behavior of superfluids on these unusual substrates is counterintuitive.

8. Monday, Apr. 22, 2002

Prof. Krzysztof Slowinski, Department of Chemistry and Biochemistry, CSULB
Title: "Long-range electron transfer in macroscopic tunneling junctions"
Abstract: Electron tunneling experiments involving macroscopic Hg-Hg junctions incorporating two alkanethiolate monolayers will be described.  I will discuss the influence of chain disorder on the efficiency of electron tunneling across single and two-component alkanethiolate bilayers.  The electron tunneling through a two-component monolayer is less efficient than tunneling through a single-component well organized monolayer.  This result is rationalized in terms of diminished electronic coupling across disorganized systems.

9. Monday, Apr. 29, 2002

Prof. Gregory Holk, Department of Geological Sciences, CSULB
Title "Stable Isotope Probes and Water-Rock Interaction in the Earth's Crust"?
Abstract: The mass dependent fractionation of hydrogen and oxygen isotopes between water and minerals varies as a function of temperature.  This provides for the tracing of the intensity of water-rock interaction as well as the identification of fluid sources for ancient hydrothermal systems.  I will describe case studies that utilize the distribution of stable isotopes to determine histories of water-rock interaction, pathways of fluid-flow, the influence of water on the tectonic evolution of mountain belts, and the role of water in the partial melting process.  The practical application of stable isotopes for mineral exploration will also be discussed.

10. Monday, May 13, 2002 MILLER COLLOQUIUM

Dr. Kristen R. Lorentzen Aerospace Corp.
Title: "Balloon and Satellite Observations of Auroras and Other Magnetospheric Phenomena"
Abstract: Energetic electrons in the magnetosphere can be extremely hazardous to satellites and humans in space.  We are particularly interested in understanding relativistic electron dynamics and how these particles are lost from the Earth's radiation belts through a process known as precipitation. We use Antarctic long-duration balloon flight observations as well as satellite measurements to study how energetic electrons are lost to the atmosphere.

last updated May. 6, 2002