Physics and Astronomy Colloquium Series

The Physics and Astronomy Colloquium Series is open to all members of the university. Unless otherwise noted, talks are held on Thursday afternoons at 4:00-5:20 in Mendocino 1015. Schedule is regularly updated as dates, titles, and abstracts are received. Please check back often. To receive updates about the Colloquium Series, please join our Events Mailing List. For past semesters' series, see our archive.

Fall 2017 Semester Schedule

Next Seminar

Thursday, September 28, 2017
4:00 PM 

Prof. Bin Liu
UC Merced

"Shape Up to Run - How Bacterial Motilities Impact Selective Cellular Morphologies"

Bacteria come in consistent shapes and sizes, which serve as one way for an individual to interact with the environment. Despite the fact that a specific morphology is important within a species, there is a lack of direct evidence on how cellular morphology affects bacterial fitness, especially regarding their dispersal capabilities and virulence factors. In this talk, I will discuss how fluid-structure interactions can potentially play a role in the evolution of cellular morphology, using both theoretical and experimental approaches. First, I will show a coupled effect of the cell shape and the flagellar alignment on the motility of rod-shaped bacteria. I will demonstrate that such an effect is sensitive to the volume of the cell body through a hydrodynamic model: when the volume is sufficiently large, the bacterium prefers a cell body in blunt shapes and oriented toward the swimming direction for optimal swimming speed; when the volume is below a critical value, determined by the flagellar geometry, the bacterium prefers an elongated shape that points away from the direction of swimming and thus wobbles. I will also compare this result with our experimental observations on several different species to show whether bacteria have “learned” fluid mechanics to shape their bodies. Finally, I will discuss the impact of motilities in the context of multi-cellular life forms, in which the morphology can be dynamically modified by addition or removal of individual bacteria. I will show that new forms of motilities can emerge from this multi-cellular morphology and its interaction with the specific mechanical environments, such as a solid-liquid interface. 

September 7, 2017
Prof. Alexander Rudolph
Cal Poly Pomona
“Cal­Bridge and CAMPARE: Engaging Underrepresented Students in Physics and Astronomy”

September 14, 2017
"What I did last summer...."
Sac State Physics Majors

September 28, 2017
“Shape Up to Run – How Bacterial Motilities Impact Selective Cellular Morphologies”
Prof. Bin Liu
UC Merced

October 5, 2017
Natural Sciences and Mathematics Undergraduate Research Reception
Special Location: University Union Redwood Room
Check with Dr. D for details....

Date: TBA
Prof. William DeGraffenreid and Mary Ann Mort
Sacramento State

October 26, 2017
Prof. John Rundle
UC Davis

Date: November 2, 2017
Dr. Laura McWilliams
Science Policy Fellow  for the California Assembly Committee on Utilities and Energy

November 9, 2017
Dr. Jason Williams
NASA Jet Propulsion Laboratory

November 16, 2017
Dr. Armela Keqi
Sac State / UC Davis 

November 30, 2017
Senior Project Talks

December 7, 2017
Senior Project Talks