News & Events

Radars are an important part of the array of tools currently in use to probe the ionosphere and through it, the plasma physical processes associated among other things with dynamos triggered by high altitude  winds and by the solar wind interaction with the earth.  The two types of radars that we use are the so-called "incoherent" and "coherent" scatter radars.  I will show that while the two types of radars rely on identical scattering processes, they use very different power levels to examine the medium.  The power level is so high in incoherent scatter radars that they are able to scrutinize low amplitude plasma waves that are in thermodynamic equilibrium with the medium.  By contrast, coherent scatter radars depend on  the presence of large amplitude plasma irregularities for their echoes. The power level requirements can be so low in the latter case that coherent radars are relatively inexpensive to build and operate, which has allowed researchers to build large networks of such radars over time.  In this talk I will illustrate how the use of these powerful radar tools has evolved and how it keeps evolving partly through technological improvements and partly through an improved understanding of the scattering processes achieved through coupled theoretical and data studies.   I will illustrate this progress with several examples from recent studies which will also make manifest the usefulness of using a large complement of tools, including simultaneous data from both types of radars and data from optical cameras, magnetometers and satellite instrumentation, just to name a few.  

Supernova explosions recycle mass and provide the elements that everything around us is composed from. I will outline the life of a star and its sudden death in the supernova event. What little we know about observed supernova progenitors will be discussed. Following the explosion, what produces the phenomena that we see as supernova remnants? I will conclude by mentioning some of the research carried out here at the University of Calgary.

In one of the planet's most extreme environments, South Pole Station Antarctica, scientists have instrumented more than a cubic kilometer of ice to construct the world's largest neutrino detector to date: the IceCube Neutrino Observatory.  Neutrinos, which interact very rarely in nature, represent an ideal messenger with their ability to travel from their point of production to detection almost entirely unimpeded.  Given its enormous size, IceCube is designed to detect the highest energy neutrinos predicted to be produced in the most violent astrophysical processes (including Gamma Ray Bursts, Black Hole collapse and Active Galactic Nuclei)  I will discuss the feat of designing and constructing the IceCube detector at the South Pole and the first results of searches for high energy neutrinos with this new window to the Universe.

The ability to discriminate current modulations produced by various nucleotides while single-stranded DNA is being electrophoretically driven through a biological nanopore offers a simple and inexpensive technique for DNA sequencing. However to realize the potential of nanopore sequencing, the molecular mechanism of DNA movement through the pore and the interactions of the nucleotide with various pore residues have to be well characterized. Here we applied computational approaches through atomistic Molecular Dynamics and Grand-Canonical Monte-Carlo/Brownian Dynamics simulations to investigate DNA translocation and interactions with the biological nanopore, a-Hemolysin (aHL), and compared the results with data obtained from experiments. Equilibrium and non-equilibrium (with an account for electric field acting on a system) MD simulations of all-atom models of homopolymeric DNA (polydA or polydC) translocating through both wild-type and mutant aHL pores provided results that qualitatively match the contrast in ionic current block produced by each base in experimental studies. Atomistic Free Energy Simulations (FES) with the “swarm-of-trajectories” method also provide for the first time insight into the potential energy landscape governing of the DNA conformational dynamics within the pore. The result also agrees with experiments indicating an asymmetric periodic potential.