Colloquium

Memorização ou compreensão: estamos ensinando o certo?, at Physics Colloquium, Universidade Federal de Pernambuco (Recife, PE, Brazil), Friday, January 27, 2012:
Education is more than just transfer of information, yet that is what is mostly done in large introductory courses -- instructors present material (even though this material might be readily available in printed form) and for students the main purpose of lectures is to take down as many notes as they can. Few students have the ability, motivation, and discipline to synthesize all the information delivered to them. Yet synthesis is perhaps the most important -- and most elusive -- aspect of education. I will show how shifting the focus in lectures from delivering information to synthesizing... Read more about Memorização ou compreensão: estamos ensinando o certo?
Memorization or understanding: are we teaching the right thing?, at Physics Department Colloquium, Queen's University (Kingston, ON, Canada), Friday, November 11, 2011:
Education is more than just transfer of information, yet that is what is mostly done in large introductory courses -- instructors present material (even though this material might be readily available in printed form) and for students the main purpose of lectures is to take down as many notes as they can. Few students have the ability, motivation, and discipline to synthesize all the information delivered to them. Yet synthesis is perhaps the most important -- and most elusive -- aspect of education. I will show how shifting the focus in lectures from delivering information to synthesizing... Read more about Memorization or understanding: are we teaching the right thing?
Nonlinear optics at the nanoscale, at Physics Colloquium, Lehigh University (Bethlehem, PA), Thursday, April 28, 2011:
We explore nonlinear optical phenomena at the nanoscale by launching femtosecond laser pulses into long silica nanowires. Using evanescent coupling between wires we demonstrate a number of nanophotonic devices. At high intensity the nanowires produce a strong supercontinuum over short interaction lengths (less than 20 mm) and at a very low energy threshold (about 1 nJ), making them ideal sources of coherent white-light for nanophotonic applications. The spectral broadening reveals an optimal fiber diameter to enhance nonlinear effects with minimal dispersion. We also present a device that... Read more about Nonlinear optics at the nanoscale
The Social Learning Network: Advancing Student Learning in the Social Sciences using Peer Instruction, You Don't Get to Subject-Matter Understanding Without Making a Few Friends First, at Cognition, Brain & Behavior Colloquium, CUNY - Brooklyn College (Brooklyn, NY, USA), Wednesday, February 16, 2011
How can I help my students learn in ways that pique their interest and enrich their subject matter understanding? In this Colloquium, we will explore this perennial question by considering an innovative, research-based teaching method called Peer Instruction (PI). Originally developed by Eric Mazur to address major gaps in students' conceptual knowledge of physics at Harvard University, this interactive pedagogical method is now widely used in classrooms at hundreds of institutions across the world. PI leverages the power of social learning and the latest advances in instructional technology... Read more about The Social Learning Network: Advancing Student Learning in the Social Sciences using Peer Instruction, You Don't Get to Subject-Matter Understanding Without Making a Few Friends First
Wrapping light around a hair, at Physics Colloquium, University of Alaska Fairbanks (Fairbanks, AK), Friday, October 29, 2010:
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was �no�. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it... Read more about Wrapping light around a hair
Subcellular surgery and nanosurgery, at Physics Colloquium, University of Notre Dame (Notre Dame, IN), Wednesday, May 12, 2010:
We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery
Subcellular surgery and nanosurgery, at Physics Colloquium, Clark University (Worcester, MA), Wednesday, April 7, 2010:
We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery
Black silicon, at University of Queensland (Brisbane, Australia), Friday, January 15, 2010:
Shining intense, ultrashort laser pulses on the surface of a crystalline silicon wafer drastically changes the optical, material and electronic properties of the wafer. The resulting textured surface is highly absorbing and looks black to the eye. The properties of this 'black silicon' make it useful for a wide range of commercial devices. In particular, we have been able to fabricate highly-sensitive PIN photodetectors using this material. The sensitivity extends to wavelengths of 1600 nm making them particularly useful for applications in communications and remote sensing.
Nonlinear optics at the nanoscale, at Physics Colloquium, University of Maryland Baltimore County (Baltimore, MD), Wednesday, November 11, 2009:
We explore nonlinear optical phenomena at the nanoscale by launching femtosecond laser pulses into long silica nanowires. Using evanescent coupling between wires we demonstrate a number of nanophotonic devices. At high intensity the nanowires produce a strong supercontinuum over short interaction lengths (less than 20 mm) and at a very low energy threshold (about 1 nJ), making them ideal sources of coherent white-light for nanophotonic applications. The spectral broadening reveals an optimal fiber diameter to enhance nonlinear effects with minimal dispersion. We also present a device that... Read more about Nonlinear optics at the nanoscale

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