Feb
02
Teaser:

 

FREE TICKETS AVAILABLE FOR A LIMITED TIME AT www.squishyphysics.eventbrite.com

 

Jan
31
Teaser:

Superbursts are the most powerful repeating thermonuclear flashes observed from accreting neutron stars. Runaway thermonuclear burning of carbon ignites deep in the star's envelope. Close to the crust, superbursts are sensitive to the ill-understood nuclear physics processes in dense neutron-rich matter. We present the latest numerical simulations of carbon burning. Comparing the tail of the simulated lightcurve to observations constrains the depth of carbon ignition, whereas the start exhibits the signs of a shock caused by detonation. Recently increasing observational evidence points at interaction between X-ray bursts and the accretion disk. As the most powerful X-ray bursts,...

Jan
31
Teaser:

Atom interferometers that use pulses of light for coherent control of matter-wave interference can be used for wide ranging studies of light-matter interactions and for realizing precision measurements in atomic physics. We describe an echo type interferometer that utilizes a relatively simple setup to manipulate laser-cooled Rb atoms in a single ground state manifold. We review progress toward a precise determination of the atomic fine structure constant and gravitational acceleration.

*Work supported by CFI, OIT, OCE, NSERC and York University

Jan
30
Teaser:

PLEASE NOTE: This is a WEBINAR

Scientists for years have been trying to better understand the mechanisms that are responsible for transport and mixing in fluid flow.  Mixing is important as it is used in everything from food preparation to energy production to biomedical devices, and is seen in both single and multiphase environments.  While mixing applications are wide ranging, a complete and proper understanding of mixing and transport mechanisms is still lacking....

Jan
29
Teaser:

PLEASE NOTE: This is a WEBINAR

Two topics in pattern formation for reaction-diffusion equations will be addressed in this talk.  In the first, I will discuss the existence proof for stationary localized spots in the planar and the three-dimensional Swift--Hohenberg equation using geometric blow-up techniques. The spots have a much larger amplitude than that expected from a formal scaling in the far field. One advantage of the...

Jan
29
Teaser:

Multicellular behavior in bacterial biofilms is intimately tied to the production of an extracellular polysaccharide (EPS) matrix that encases the cells and provides physical integrity to the colony as a whole.  As a colony grows from a few cells into a biofilm, a sudden increase in EPS production generates osmotic stresses that cause the biofilm to expand. Moreover, EPS production is triggered by a nutrient depletion gradient that develops in the biofilm due to diffusive mass transport limitations. These polymer physics based biofilm behaviors...

Jan
28
Teaser:

A great part of physics deals with motion, and the essence of sports is the human body in motion.  The components of the human body that produce motion, namely the skeletal muscles and bones, and the sports equipment itself are bound by the laws of physics.  Aspects of various sports, including baseball, basketball, karate, figure skating, golf, tennis, long jump, and more, will be examined using introductory-level physics.  We will also discuss whether we have reached our limits in human performance in certain sports.  All who appreciate the workings of the human body and the...

Jan
24
Teaser:

Supermassive black holes are amazingly exotic and yet ubiquitous objects, residing in the centers of essentially all stellar bulges in galaxies. Recent years have seen remarkable advances in our understanding of how these black holes form and grow over cosmic time, and how energy released by active galactic nuclei (AGN) connects the growth of black holes to their host galaxies and large-scale structures. I will review some recent work that explores these connections, with a focus on statistical studies of AGN clustering and the links between black hole growth and and star formation. I will highlight some new insights into how and when AGN "feedback" is important for galaxy...

Jan
23
Teaser:

PLEASE NOTE: This is a WEBINAR

The interplay of shearing and rotational forces in fluids  significantly affects the transport properties of turbulent fluids  such as the heat flux in rotating convection and the angular momentum  flux in a fluid annulus between differentially rotating cylinders. A  numerical investigation was undertaken to study the role of these  forces using plane Couette flow subject to rotation about an axis  perpendicular to both wall-normal and streamwise directions. Using a  set of progressively...

Jan
17
Teaser:

Current study in quantum dynamical evolution of complex systems investigates quantum systems characterized by fluctuations and quantum correlations.  Spin-1 condensates are predicted to generate non-classical states with quantum correlations, specifically squeezed states in the early low depletion limit and highly non-Gaussian distributions in the long term beyond the low depletion limit.  These states are created due to the quantum fluctuations about an unstable equilibrium in the spin-nematic subspaces to which the system is initialized.  In this talk I will discuss the...

Jan
16
Teaser:

PLEASE NOTE: This is a WEBINAR

The transport of particulate material by fluid flow is a problem with far reaching applications. Isotropic particles that are very small and neutrally buoyant behave as Lagrangian tracers and move with the local fluid velocity. However, particles that are large or density mismatched compared to the fluid have different dynamics from the local fluid. The rotational dynamics of anisotropic particles is different from spherical tracers and this fascinating problem is central for many applications ranging from cellulose fibers in paper making to dynamics of ice...

Jan
15
Teaser:

I will discuss three examples describing the utility of understanding and/or exploiting both epigenetic and genetic variability in populations of yeast cells. First, I describe an unappreciated and dominant role for cell-cycle phase on transcriptional variability and dynamics. We show that for a model “noisy” gene in S. cerevisiae, the common view that large variability observed in mRNA numbers is due to a transcriptional bursting, where a promoter undergoes random and intermittent periods of active transcription, is incomplete and possibly...

Jan
14
Teaser:

Despite their everyday familiarity, thin sheets (paper, plastic, fabric, etc.) display remarkable and complex behaviors that still challenge theoretical description. The intricate coupling between the geometry of surfaces and the elasticity of a thin sheet necessarily leads to the formation of singularities, nonlinear elasticity, and geometric frustration. Nevertheless, multicellular organisms - like you - develop their three dimensional structures in part by exploiting these elastic phenomena. These considerations have led to new theoretical and experimental tools to shape elastic sheets into...

Dec
11
Teaser:

X-ROS signaling is a novel redox signaling pathway that links mechanical stress to changes in [Ca2+]i.  This pathway is activated rapidly and locally within a muscle cell under physiological conditions, but can also contribute to Ca2+-dependent arrhythmia in heart and to the dystrophic phenotype in heart and skeletal muscle 1, 2.  Upon physiologic cellular stretch, microtubules serve as mechanotransducers to activate NADPH oxidase 2 (NOX2) in the transverse tubules and sarcolemmal membranes to produce reactive oxygen species (ROS).  In heart, the ROS acts locally to activate ryanodine receptor Ca2+...

Dec
10
Teaser:

Blazar astronomy is rapidly progressing thanks in large part to the successes of the Fermi Gamma-ray Space Telescope and the ground-based gamma-ray telescopes. More than 1000 active galaxies have been detected at GeV energies, and nearly 50 at Very-High Energies (VHE,  > 100 GeV). We can now explore multiwavelength and multi-messenger connections in unprecedented detail, and derive the astroparticle implications of those results. In this presentation, leptonic and hadronic spectral modeling of blazars is reviewed with the intent of identifying ultra-high energy cosmic rays (UHECRs) in  the spectral energy...

Pages