All posts by Jesse Rogerson

Hana Dobrovolny – Invited Speaker

Invited Speaker – Dr. Hana Dobrovolny

Time: 11:30- 12:00

Biography:

Dr. Dobrovolny completed her undergraduate degree at the University of Winnipeg. She then moved to Pennsylvania for her Master’s at Bryn Mawr College, and completing her PhD at Duke University. She has now returned to Canada working at Ryerson University as a Postdoctoral Fellow with Dr. Beauchemin in the PhyMBIE (Physical Modelling in Biology, Immunology, and Ecology) group.

She has published papers in the Journal of Cardiovascular Electrophysiology, the Biophysical Journal, and Physical Review Letters.

She even teaches here at York University. She is the course director for Biophysics I, and II, third and fourth year courses in the biophysics program.

Modelling of influenza infections

Influenza is a serious disease that kills thousands of people
every year and can kill millions in periodic pandemics. Modelling of the
with-in host dynamics of influenza is an emerging field that has helped to
provide insight into the disease process. Simple mathematical models have
shed light on the internal dynamics of the disease and have been used to
characterize influenza virus. They have also been used to test the effects
of drug therapy. This talk will present some simple models of influenza
dynamics and will discuss how they have influenced our understanding of this
disease.

2010 PAGE Conference – Announcement

Hi all,

The Phyisics and Astronomy Graduate Executive is proud to announce the 2010
PAGE Conference held Thursday October 14, 2010 in Room 121 Chemistry Building,
York University. Attendance is free!

Visit us at
http://yupage.blogspot.com/
and click on the ‘2010 conference label’

Talks on astronomy, atomic and molecular optics, high energy, and biophysics research areas, especially on graduate research will be highlighted this year.

This conference gives an excellent chance for graduate students to come out practice their own abilities and for everyone to see what’s happening within the physics department here at York.

This year, the invited speaker is Dr. Hana Dobrovolny, from Ryerson University, who will be speaking about Modeling of Influenza Infections.

Refreshments will be provided during the conference and lunch will be provided free by PAGE at 12:00.

If you have any questions, please feel free to send an email to PAGE
directly at YUPAGA@gmail.com or any of the PAGE members directly.

See you all there,
Your Physics and Astronomy Graduate Executive,
Mok, Carson (President)
Vergados, Panagiotis (VP, FGS and Departmental representative)
Rogerson, Jesse (VP Finance, GSA representative)

Call for Abstracts 2010

Hi all,

The Phyisics and Astronomy Graduate Executive is proud to announce the 2010
PAGE Conference held Thursday October 14, 2010 in Room 121 Chemistry Building,
York University.

All topics related to research in physics, astronomy and atmospheric physics
are welcome. The aim of this issue is to highlight the ongoing research in these
areas, with a particular emphasis on the graduate studies being conducted at
York University. This conference provides an opportunity for students to
present their work in an interdisciplinary environment.
This year, we have our annual student competition for the Ralph Nicholls
award with a monetary value of $100 for the first winner. Prizes will also be
awarded to the second and third place.

Submission guidelines:
Abstracts should be submitted via email to:
vergados [at] yorku [dot] ca
rogerson [at] yorku [dot] ca
or cmok [at] yorku [dot] ca

Abstracts should not exceed 250 words.
Deadline for submission of abstracts: October 5, 2010
Notice of acceptance: October 7, 2010

Guidelines for oral presentations:
Due to the interdisciplinary nature of the conference, the authors should
aim at putting together a non-technical presentation and focus on the following:

15-minute talk
Understandable by a 4th year physics student
General description of the problem
Applications

More information and guidelines for the Ralph Nicholls award can be found
at:
http://yupage.blogspot.com/search/label/The%20Ralph%20Nicholls%20graduate%20
award%20in%20science%20communication

Cheers,
Your Physics and Astronomy Graduate Executive,

Mok, Carson (President)
Vergados, Panagiotis (VP, FGS and Departmental representative)
Rogerson, Jesse (VP Finance, GSA representative)

The 2009 PAGE conference

When: October 15th, 2009
Where: The Paul Delaney Gallery (The Norman Bethune College, 320)

Attendance is free. We strongly encourage graduate and undergraduates to participate this event.

Organizing Committee:

Alireza Rafiee (Chair of the Organizing Committee and Ralph Nicholls Graduate Award)
Carson Mok cmok@yorku.ca
Panagiotis Vergados vergados@yorku.ca

The conference poster

Conference Schedule:

Time ………. Speakers
—————————-
10:00……… Reception [Coffee and Doughnuts] + Surprise Gifts for early birds
10:10 …….. Opening
10:20 …….. Ioannis Haranas
10:40 …….. Laura Chajet
11:00 …….. Coffee break
11:10 ……… Invited Speaker Dr. Veronica Sanz
12:00 …….. Lunch Provided by PAGE
13:20 …….. Steve Beale
13:40 …….. Maria Georgina Carrillo Ruiz
14:00 …….. Robert Berthiaume
14:20 …….. Coffee Break
14:40 …….. Daneil Fitzakerly
15:00 …….. Jesse Rogerson
15:20 …….. Yaniv Gura
15:40 …….. Invited Speaker Dr. Tom Kirchner
16:30 …….. Presenting the Award
17:00 …….. Closing

Link to Abstracts

Talks are 15+5 minutes and 45+5 minutes long.

About the Physicist Gustav Robert Kirchhoff :

Gustav Robert Kirchhoff (12 March 1824 – 17 October 1887) was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects. He coined the term “black body” radiation in 1862, and two sets of independent concepts in both circuit theory and thermal emission are named “Kirchhoff’s laws” after him. The Bunsen-Kirchhoff Award for spectroscopy is named after him and his colleague, Robert Bunsen.

More about G.R. Kirchhoff

The 2009 PAGE conference Abstracts

Abstracts:

Dr. Tom Kirchner (Invited Speaker)

Atomic systems in time-dependent fields:
insights into the fundamental few-body problem
The quantum mechanical few-body problem has challenged physicists ever since the foundations of quantum theory were laid in the 1920s. It might be embarrassing, but even if the mutual forces between the particles are known the solutions of the fundamental equations are not except for a few special cases.

Collisions of atoms and molecules as well as their interactions with laser radiation are well suited to illustrate this worrisome, but also fascinating situation. They will be the topic of my talk. In particular, the role of theory and computations will be discussed and some recent results and insights deduced from them will be presented.

Dr. Veronica Sanz (Invited Speaker)

Having fun at the energy frontier

Many hopes hang on the Large Hadron Collider. Among many conundrums in Particle Physics,the LHC is expected to reply to these questions: what is the origin of mass? which particleis responsible of Dark Matter in the Universe? are there more dimensions than the four we experience everyday? are matter and energy secretly related? In this talk I will outline how the LHC is going to look for those answers during its first years of running.

Steve Beale

Searching for Charge-Parity Violation

The visible universe is composed of almost entirely matter with little or no antimatter. However, matter particles are always produced with an antimatter partner, hence there should be a balance of matter and antimatter. This is the baryon asymmetry problem. To account for this asymmetry, there must be new sources of Charge-Parity (CP) violation. One possible source is matter-antimatter oscillations in the Bs meson system. An asymmetry in the transition rate to/from matter to antimatter would be a clear indication of CP violation. This effect is predicted to be very small in the standard model of particle physics, but may be enhanced by new physics. I will present a measurement of this CP violating charge asymmetry and show how impacts current searches for new physics.

Ioannis Haranas

Satellite motion in a non-singular gravitational potential

The scope of this paper is to study the effects of a non-singular gravitational potential on satellite orbits by deriving the time rates of change of its orbital elements. This is achieved by writing a non-singular potential expression as a function of the orbital elements and then substituting it into the Lagrange planetary equations. In particular, we derive expressions for high and low frequency as well as secular effects and we evaluate them numerically using the low Earth orbiting satellite mission GRACE. We compare the secular effects with the corresponding general relativistic results and we show that the secular effect of the first disturbing term R1 on the perigee shift is equal to

, an effect that most likely will not be easily separated from the corresponding relativistic that is three times greater in magnitude. Finally, the effect of R2 term on the time rates of change of the perigee and mean anomaly for missions like GRACE will not be easily observed since they would also require extremely long orbiting time scales.

Daniel Fitzakerley

Precision Measurement of the 23P2 -to- 23P1 helium Fine Structure Interval

The fine structure constant, α, is a fundamental constant of nature that represents the strength of the coupling interaction between charged particles. Comparisons of experimental values and theoretical predictions of the n=23PJ fine structure intervals of Helium can be used to determine α. The goal of my research is complete a measurement of the 23P2-to-23P1 interval to a precision of 90 Hz (40 ppb). This level of precision is reached by using the Ramsey separated oscillatory field technique wherein the natural linewidth is narrowed using a pair of microwave pulses. This work builds on a 150 ppb measurement completed by our group last year (Phys. Rev. A 79, 060503 (2009): Borbely et al.). If the larger 23P1-to-23P0 interval is measured with the same precision as the smaller 23P2-to-23P1 interval using this technique, the fine structure constant, α, will be determined to a precision of 1.5 ppb.

Maria Georgina Carrillo Ruiz

Field theories on a lattice with many flavours

Interest in non-Abelian lattice gauge theories with many flavours has increased in recent years. These studies aim to address physics that may appear at the energy of the Large Hadron Collider or beyond. In particular, the knowledge of the phase diagram of these theories as a function of the number of colors, flavours and matter representation plays a fundamental role when trying toconstruct viable extensions of the Standard Model. In this talk, we review the lattice formulation of such theories and take SU(2) gauge theory as a casestudy.

Laura Chajet

MHD Modeling of Disk Winds

Broad emission lines (BELs), one of the characteristic features of active galaxy nuclei (AGNs) spectra, are generally single-peaked and blueshifted with respect to the rest frame wavelength. It has been shown (e.g. Murray & Chiang 1997) that these observational results can be explained by assuming that the emission is produced in a wind off the accretion disk surrounding the central black hole. This feature was also explained by Emmering et al. (1992), but considering a magnetocentrifugal wind consisting of clouds. Here we present some preliminary results of the combination of both approaches considering a magnetocentrifugal continuous outflow.

Robert Berthiaume

A Low Cost MOPA System for Laser Spectroscopy

The low cost and robust nature of diode lasers make them suitable for applications in manufacturing, telecommunications, medicine and data handling. Further, they can be configured to have a very narrow linewidth and to be highly tunable, which makes them an attractive tool for spectroscopic research. I will present an overview of a campaign to develop a homebuilt Master Oscillator Powered Amplifier system which includes External Cavity Diode Lasers, Tapered Amplifiers, and Optical Isolators. The master oscillator is built with the same laser diode found in most CD players. The system produces a 600mW single mode beam at 780nm for a tenth of the cost of commercially available systems. Applications include magneto-optical trapping, atom interferometry, and inertial sensing.

Jesse Rogerson

An overview of Giant arcs

Recently, multiple examples of giant arcs created by gravitational lensinghave been discovered. Due to the magnification properties of lensing, these systemsprobe fainter sources than otherwise possible, resulting in extending galaxy/quasarstudies to higher redshifts. Also, due to their high redshift and extended image,these sources provide a unique look at the intergalactic medium. In this talk, Iwill highlight a few examples of giant arcs, and summarize the key conclusions reached by studying these lensing systems.

Yaniv Gura

The Creation of the H−+ Atom

Our goal is to create, detect and study an exotic atom made up of an H- ion along with a positron. Our 1st goal toward eventual spectroscopic measurements of this exotic atom is to create it in a highly excited state and detect it. A bound molecule made up of these constituents (positronium hydride) has been indirectly detected by colliding positrons with methane gas and looking for CH3+ [D. M. Schrader et al, PRL 69, 57]. Our research will produce a positronic atom in a Rydberg state with the positron weakly bound to the H- ion in an atomic configuration rather that H bound to Ps in a molecular state. A beam of H- ions will be directed towards a cloud of positrons that will be waiting in a particular potential well created by a trap consisting of a series of consecutive aluminum and copper hollow cylinders, called electrodes. The H− ions will undergo some process emerging with a positron orbiting at a Rydberg state. Further down the electrode stack the H−+ atom will encounter a strong electric field gradient created by the electrodes. This will strip the positron from the H−+ atom which will allow us to accumulate and detect the stripped positrons. The detection of the positrons in this ionizing potential well will be evidence of the production of H−+ atoms. Tedious optimization has led to a record number of approximately 6.5 million accumulated positrons for this apparatus over 120 seconds and a 100nA beam of H- ions has been produced using a Colutron Ion Gun. Production of this atom will open the door to precise spectroscopic measurements of this atom and may provide greatly improved understanding of the H− ion core.