Yoshinori Ohsumi to Receive Rosenstiel Award Wednesday, April 6

ohsumi220Biologist Yoshinori Ohsumi will receive the 45th Rosenstiel Award for Distinguished Work in Biomedical Science this Wednesday, April 6th at 4:00 pm in Gerstenzang 123. At that time, he will present a lecture titled, “Lessons from yeast: Cellular recycling system, autophagy”.

Ohsumi is a cell biologist and professor at the Tokyo Institute of Technology’s Frontier Research Center in Japan. He is one of leading experts in the world on autophagy, a process that allows for the degradation and recycling of cellular components. The Rosenstiel Award is being given to Ohsumi in recognition of his pioneering discoveries in autophagy.

Learn more about Professor Ohsumi and his research at BrandeisNow.

DIY your own Programmable Illumination Microscope

The Fraden Group describes how to build your own Programmable Illumination Microscope in the American Journal of Physics

Have you ever marveled at the equipment used in a research lab? Have you ever wondered how a specialized piece of equipment was made? Have you ever wondered how much it would cost to build your own research microscope? Have you ever considered trying to make your own research microscope? The details on how the Fraden Group builds their Programmable Illumination Microscope for under $4000 was recently published in the American Journal of Physics.

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The Programmable Illumination Microscope or PIM is a highly specialized microscope where the illumination for the sample being imaged comes from a modified commercial projector, nearly identical to the ones mounted in every classroom. For the PIM the lens that projects the image onto the screen is removed and replaced with optics (often the same lens in reverse) that shrinks the image down so that it can be focused through the microscope objective onto the sample. The light coming from the projector, which is the illumination source for the microscope, can be modified in realtime based on the image being captured by the camera. Thus the illumination is not only programmable but can also be algorithmic and provide active feedback.

This new publication in the American Journal of Physics, which is published by the American Association of Physics Teachers, is intended to help small teaching and research labs across the country develop their own PIMs to be built and used by undergraduate students. The paper includes schematics and parts lists for the hardware as well as instructions and demonstration code for the software. Any other questions can be directed to the authors Nate Tompkins and Seth Fraden.

Nature News Feature Highlights Dogic Lab Active Matter Research

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Biological material is constantly consuming energy to make things move, organize information such as DNA, or divide cells for reproduction; but building a fundamental theory which encompasses all of the features of biological matter is no easy task. The burgeoning field of active matter aims to understand these complex biological phenomena through physics. Active matter research has seen rapid growth over the last decade, but linking existing active matter theories with experimental tests has not been possible until recently. An explosion of biologically based and synthetic experimental systems as well as more detailed theories have arrived in recent years, and some of these foundational experiments have been conducted here at Brandeis University. Recently, a Nature News Feature (The Physics of Life) has highlighted work from Zvonimir Dogic’s lab in an article about the field of active matter and the physics which endeavors to understand biology.

 

Pairs of Supermassive Black Holes May Be Rarer Than Earlier Thought

Image by David Roberts

Image by David Roberts

Recent research by David H. Roberts, William R. Kenan, Jr. Professor of Astrophysics at Brandeis, has shown that pairs of supermassive black holes at the centers of galaxies are less common than previously thought. This suggests that the level of gravitational radiation from such systems is lower than earlier predicted. This work was in collaboration with Lakshmi Saripalli and Ravi Subrahmanyan of the Raman Research Institute in Bangalore, and much of the work was done by Brandeis undergraduate students Jake Cohen and Jing Liu. It has recently been published in a pair of papers in the Astrophysical Journal Supplements and Astrophysical Journal Letters.

Gravitational waves are ripples in space-time predicted by Einstein’s 1915 General Theory of Relativity. Propagating at the speed of light, they are produced in astrophysical events such as supernovae and close binary stars.

No direct experimental evidence of the existence of gravitational waves has been found to date. We know that they exist because they sap energy from the orbits of binary systems, and using ultra-precise radio astronomy it has been shown that the changes in binary orbits of pairs of pulsars (magnetized neutron stars) are precisely as predicted by General Relativity. Hulse and Taylor were awarded the Nobel Prize in Physics for their contributions to this work.

The largest source of gravitational waves is expected to be the coalescence of pairs of supermassive black holes in the centers of large galaxies. We know today that galaxies grow by mergers, and that every galaxy harbors a massive black hole at its center, with mass roughly proportional to the galaxy’s mass. When two massive galaxies merge to form a larger galaxy, it will contain a pair of black holes instead of a single one. Through a process involving the gravitational scattering of ordinary stars the two black holes migrate toward each other and eventually coalesce into a single even more massive black hole. The process of coalescence involves “strong gravity,” that is, it occurs when the separation of the two merging black holes becomes comparable to their Schwarzschild radii. Recent developments in numerical relativity have made it possible to study the coalescence process in the computer, and predictions may be made about the details of the gravitational waves that emerge. Thus direct detection of gravitational waves will enable tests of General Relativity not achievable any other way.

In order to predict the amount of gravitational radiation present in the Universe it is necessary to estimate by other methods the rate at which massive galaxies are colliding and their black holes coalescing. One way to do this is to examine the small number of radio galaxies that have unusual morphologies that suggest that they were created by the process of a spin-flip of a supermassive black hole due to its interaction with a second supermassive black hole. These are the so-called “X-shaped radio galaxies” (“XRGs”), and a naive counting of their numbers suggests that they are about 6% of all radio galaxies. Using this and knowing the lifetime of such an odd radio structure it is possible to determine the rate at which massive galaxies are merging and their black holes coalescing.

Roberts et al. re-examined this idea, and made a critical assessment of the mechanism of formation of XRGs. It turns out that other mechanisms can easily create such odd structures, and according to their work the large majority of XRGs are not the result of black hole-black hole mergers at all. They suggest as a result that the rate of supermassive black hole mergers may have been overestimated by a factor of three to five, with the consequence that the Universe contains that much less gravitational radiation than previously believed. In fact, recent results from searches for such gravitational waves have set upper limits below previous predictions, as might expect from this work.

For more information:

 

IGERT Summer Institute – July 27 to August 7, 2015

IGERTBrandeis is hosting a two-week summer institute for graduate students in the mathematical sciences from July 27-August 7.  This will combine the annual summer institute of Brandeis’ Geometry and Dynamics IGERT program, with a sequel to the US-India Advanced Studies Institute on thermalization, held two years ago in Bangalore.

Topics:

  • Large deviation theory
  • Statistics of extreme events
  • The large N expansion in statistical and quantum physics
  • Statistical fluid dynamics
  • Quantum information and quantum gravity
  • Thermalization in Quantum Systems

Lecturers:

Sumit Das (U. Kentucky)
Chandan Dasgupta (IISC, Bangalore)
Rajesh Gopakumar (HRI, Allahabad and ICTS)
Alex Maloney (McGill University)
Satya Majumdar (LPTMS, Paris)
Sanjib Sabhapandit (Raman Research Institute, Bangalore)
Peter Weichman (BAE systems)

Organizers:

Albion Lawrence
Bulbul Chakraborty

Registration:

There will be no registration fee, but the venue will have limited capacity, so interested students should register by sending an email to Catherine Broderick (cbroderi@brandeis.edu) by July 4. Please list your affiliation, your year in graduate school, any publications, and the name of your PhD advisor.

Additional information can be found at www.brandeis.edu/igert/.

New Faculty Member Joins the Physics Department

A new faculty member is joining the Physics department starting on January 1, 2016.

W. Benjamin RogersW. Benjamin (Ben) Rogers is currently a research associate in Applied Physics at Harvard University under the supervision of Professor Vinothan Manoharan. Before coming to Harvard, he completed his Ph.D. in the Department of Chemical and Biomolecular Engineering at the University of Pennsylvania and his B.S. in Chemical Engineering from the University of Delaware.

Ben’s research focuses on developing quantitative tools and design strategies to understand and control the self-assembly of soft matter. He is interested in elucidating the role of specificity in complex self-assembly, designing responsive nanoscale materials by controlling phase transitions in colloidal suspensions, and understanding how coupled chemical reactions give rise to active materials, which can move, organize, repair, or replicate. At the intersection of soft condensed matter, biophysics, and DNA nanotechnology, his research utilizes techniques from synthetic chemistry, optical microscopy, micromanipulation, and statistical mechanics.

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