Kristy McQuinn, Rutgers University

The Baryon Cycle in the Smallest of Star-Forming Galaxies

Our view of galaxy evolution has expanded to include not just the evolution of individual galaxy components (gas, stars, chemical elements), but the cyclical interplay of a galaxy with its surroundings. Frequently termed the 'baryon cycle', the galaxy evolution framework now includes: how gas is accreted onto galaxies, turned in stars, ejected out of galaxies via energetic feedback processes, and potentially re-accreted.

Dr. Chris Williams, Brigham & Women's Hospital

MRI-Guided Adaptive Radiation Therapy: Improving Precision in Cancer Therapy

Radiation therapy treatments have traditionally used x-ray imaging to ensure that a patient is accurately positioned before treating them with a beam of ionizing radiation. In the past several years, new treatment machines have been developed that combine magnetic resonance imaging (MRI) systems with linear accelerators, enabling MRI-guidance before and during treatment delivery. These devices have the potential to improve our ability to visualize and treat soft-tissue tumors as well as to compensate for motion and changes in a patient’s anatomy.

Dr. Neil Turok, Director Emeritus; Perimeter Institute

Quantum Universe

Observations show the cosmos to be astonishingly simple, and yet deeply puzzling, on the largest accessible scales. How did everything we see emerge from a singular “point” in the past? Why is there a cosmological constant (or dark energy) and what fixes its value? What caused the density variations which seeded the formation of galaxies? All these questions involve the interplay between quantum mechanics and spacetime.

There is no scheduled Physics Colloquium for Friday, October 18 2019.

Dan Milisavljevic, Purdue University

Multi-messenger Autopsies of Stellar Death

The expanding zoo of astronomical transients has become one of the most important driving forces of scientific discovery in extreme astrophysics. Increasingly sophisticated all-sky surveys are uncovering unexpected phenomena that are forcing radical revisions to long accepted models of massive star evolution and their compact remnant objects. These discoveries, which will increase by orders of magnitude in the upcoming decade, are shaping the priorities of the next generation of science facilities such as the Large Synoptic Survey Telescope and Extremely Large Telescopes.

Dr. Narae Kang, Intel Corp.

Design, Fabrication, and Characterization of Nanoelectronic Devices: From Carbon Nanotubes to Graphene, and Beyond

Fabrication of high-performance electronic devices using novel semiconductors is essential for developing future electronics applications such as large-area, flexible and transparent displays, sensors and solar cells. In the first part of my talk, I will discuss the fabrication of nanoelectronic devices and investigation of their transport properties using carbon nanotubes (CNTs) and graphene as electrode materials.

No colloquium this week - Dr. Narae Kang has been rescheduled for 4 October 2019.

Mark C. Williams, Northeastern University

How Proteins Use Thermodynamics to Fight Over DNA

Optical tweezers allow us to probe the interactions of proteins with single DNA molecules and apply very small forces. Measurement of force-dependent DNA conformations allows us to quantify interactions that govern cellular function. DNA forms a stable double-helix in order to store the genetic information for most organisms. However, in the process of replicating an organism’s genome, the two strands of the helix must be separated to form single-stranded DNA (ssDNA). This intermediate state is vulnerable to interference from many cellular processes and is therefore tightly regulated.

Andrew Baker, Rutgers University

Dusty Star-Forming Galaxies at High Redshift
Interstellar dust grains can collectively scatter, redden, and attenuate the light from a galaxy's stars-- in some cases, so effectively that a galaxy can become nearly undetectable at rest-frame ultraviolet and optical wavelengths. Starting in the late 1990s, astronomers have come to understand that luminous but optically obscured systems are much more prevalent at high redshifts (i.e., earlier times) than in the local universe, and that they make important contributions to the overall history of cosmic star formation.

There is no Physics colloquium currently scheduled for this date.