Sep
23
Teaser:

Dark matter plays an important role in our current understanding of the universe.  Low surface brightness spiral galaxies are particularly excellent laboratories for probing the dark matter distribution and placing constraints on theoretical models.  I will discuss the observational techniques used to study these galaxies and their dark matter halos.  I will also discuss how well current dark matter models describe the observations and suggest how they might need to be updated.

Sep
18
Teaser:

Computational fluid dynamic simulations are providing new insights into the connections between patient-specific hemodynamic flows and the initiation, progression and treatment of cerebral aneurysms. Recent studies linking aneurysm rupture to the formation of vortices have motivated the need for a more fundamental understanding of swirling blood flow patterns and their evolution during the cardiac cycle. In this talk, I describe how dynamical systems theory is being used to advance our knowledge of vortex dynamics within cerebral aneurysms.

Sep
04
Teaser:

Entanglement has recently emerged as an important conceptual tool in quantum many-body physics.  I will explain why we care about entanglement in quantum matter and why we are interested in the physics of highly ntangled quantum states.  I will also show how entanglement has led us to new phases of matter, new ways to characterize phases and phase transitions, novel numerical techniques, and useful conceptual advances. I will conclude with a discussion of the prospects for measuring...

Sep
03
Teaser:

Using force spectroscopy mode of Atomic Force Microscopy (AFM) one can measure physiologically relevant pN forces between an AFM tip and a biomolecule with a mean displacement resolution of about 0.1 nm. The last 15 years have witnessed an explosion of interest in single molecule force spectroscopy fueled by: 1) new possibilities to advance in protein folding, 2) possibilities to elucidate molecular mechanisms of various cellular processes, and diseases, and 3) efforts to understand...

Aug
28
Teaser:

I discuss "simple" dynamical systems on networks and examine how network structure affects dynamics of processes running on top of networks.  I consider results based on "locally tree-like" and/or mean-field and pair approximations and examine when they seem to work well, what can cause them to fail, and when they seem to produce accurate results even though their hypotheses are violated fantastically.  I'll also present a new model for multi-stage complex contagions--in which fanatics produce greater influence than mere followers--and examine dynamics on networks with hetergeneous...

Aug
21
Teaser:

Well-controlled experiments in pipe flow began at least as early as those by Reynolds himself (1883).  Forming a model for transition to turbulence, however, has taken a long time to develop.  The first nonlinear solutions to the equations governing fluid flow in a pipe were discovered only 10 years ago (Faisst and Eckhardt 2003), but since this time our understanding of the underlying nonlinear dynamics has developed thick and fast.  I begin by reviewing some of the progress that followed the discovery of travelling wave solutions.  For the future, it will be...

Jul
09
Teaser:

DNA coils undergo  striking conformational transitions when it is confined to volumes with dimensions smaller than one of the characteristic lengths of the molecule.  We are particularly interested in confinement to channels less than two persistence length wide, and hundreds of microns long.  In these channels, DNA extends to 50 % of its contour length and more, thus establishing a clear connection between location and the linear "genetic address" expressed in base pairs. We can fabricate nanochannel systems with arbitrary configurations in two dimensions using fused silica, and thus are...

Jun
25
Teaser:

Characterization of the mechanical properties of cells, as well as the tissues and extracellular matrices (ECM) in which they reside, requires microscale manipulation platforms that allow precise measurement of their local rheology. To achieve this, my laboratory has developed a suite of NdFeB-based magnetic tweezers devices optimized for biomaterials characterization. In this talk, I will present the design and construction of three new microscope-mounted magnetic tweezers devices that allow controlled forces to be applied locally to networks, cells, and tissues while their deformation is...

Pages