Spring 2009 Seminars
Seminars are held on Tuesdays, 3:45-4:45pm in SB110, unless otherwise noted. Meet at 3:30 in SB157 for refreshments (refreshments are available even on Tuesdays with no seminar!). See Calvin's Visitor Resources for maps and directions to the Science Building.
Tuesday, February 3
|Snacks at 3:30 in SB157 Seminar class at 3:45 pm
Tuesday, February 10 Refreshments in SB110
Presentation by the Astronomy in the Southwest interim class
|Tuesday, February 17||Snacks at 3:30 in SB157 Seminar class at 3:45 pm|
|Tuesday, February 24||
Part 1: Rac1 plays an important role in development of electrical excitability in PC12 cells
|Prof. L. Haarsma and students Joe Holtrop and Susan Bardolph|
|Tuesday, March 3||Snacks at 3:30 in SB157 Seminar class at 3:45 pm
|Tuesday, March 10||Our Search for Long-Range Krypton Molecules||Prof. M. Walhout and students Jennafer Banister and Zach Smith|
|Tuesday, March 17||Snacks at 3:30 in SB157 Seminar class at 3:45 pm||
|Tuesday, March 24
No seminar, snacks or colloquium
|Tuesday, March 31||The Flora Asteroid Family: Picking up the Pieces||Student Melissa Haegert|
|Tuesday, April 7||Snacks at 3:30 in SB157 Seminar class at 3:45 pm|
|Tuesday, April 14||Possibility in a "p-n patchwork": electronic properties of inhomogeneous materials||Dr. Harold Schnyders, Department of Physics, GVSU|
|Special Physics and Astronomy Seminar :
Wednesday, April 15
|Brent Bos, NASA Goddard Space Flight Center|
|Tuesday April 21||Snacks, no class|
Tuesday April 28
|No snacks, seminar class or colloquium|
Tuesday May 5
|An Investigation of Scientific Reasoning Skills in Scientists and Students: Implications for Scientific Literacy and Conceptual Change||Professors J. Jadrich and C. Bruxvoort|
|Tuesday May 12|
February 10: Astronomy in the Southwest
Astronomy in the Southwest interim class
An intrepid crew of students travelled the remote corners of New Mexico and Arizona, braving all from the subfreezing predawn of mountaintops to the intense midday sun of Tucson, to get a hands-on perspective on astronomy. We saw innumerable stars with our unaided eyes from dark desert skies and much more using large telescopes. We had guided tours of the latest telescope technology and saw the mirrors being constructed for the telescopes that will become the world’s largest in the near future. We experienced the Earth as a planet in a new way traveling on and off of the Colorado Plateau, catching glimpses of its ancient past and indications of its future as the state if New Mexico is literally ripping in two. The seminar will give an overview of what we experienced and the new perspective it has given us on God’s awesome creation. Photo
February 24: Part 1: Rac1 plays an important role in development of electrical excitability in PC12 cells
Student Joe Holtrop
When exposed to Nerve Growth Factor (NGF), PC12 cells become like nerve cells--they stop dividing, they grow long neurites, and they become more electrically excitable. One particular protein, Rac1, was known to be important for the growth of neurites. We used patch clamp electrophysiology to measure voltage-activated Ca++, Na+, and K+ currents in PC12 cells which had been transfected with DNA or siRNA to control Rac1. Our data indicates that Rac1 does play an important role in the development of increased electrical activity.
February 24: Part 2: Effects of K+ channel blockers in UV-B induced K+ currents and apoptosis in corneal epithelial cells
Student Susan Bardolph
When ultraviolet light damages cells on the surface of the eye (corneal epithelial cells) potassium channels in the cell membrane open, allowing potassium to leave the cell. This is an important early step compared with other extracellular fluids. In previous work we showed that high levels of potassium in extracellular fluid can help to prevent potassium from leaving the cell and also prevent apoptosis. There are many types of potassium channels, each sensitive to different chemical blockers. In this research, corneal epithelial cells were treated with various blockers to determine which channel types are responsible for potassium loss after UV exposure.
March 31: The Flora Asteroid Family: Picking up the Pieces
Student Melissa Haegert
In the Fall of 2007 we presented new evidence of a 500 million year old collision near the inner edge of the asteroid belt. Specifically, we found a group of asteroids (the Flora family) for which the size of their orbits correlated with their physical size. Our hypothesis was that they were all shards from a collision that occurred near the biggest piece, and that over time sunlight has pushed them gradually away from the collision site (a process known as the Yarkovsky effect). We proposed a strong test of the hypothesis: measure the directions of spin of the collisional shards and compare them to those of nearby asteroids. If the hypothesis is true, then the shards should all spin in a prograde sense, while the other asteroids should not.
To determine these spins we have since observed these asteroids for over 300 nights, tracking the light variations due to rotation. In this seminar, we will report the conclusions we can now draw from these observations. We will also propose a second test of the hypothesis that would permit a more detailed exploration of the dynamics of asteroid spins.
Wednesday, April 15: The Phoenix Mars Lander & the James Webb Space Telescope
Brent Bos, NASA Goddard Space Flight Center
The Phoenix lander arrived on the north pole of Mars last summer and dug into the surface with its robotic arm in the quest to find and understand the distribution of water on the planet. Dr. Bos worked on the team that built and operated the robotic arm camera, and will report the mission’s findings. Dr. Bos is also on the team designing the optical systems of the James Webb Space Telescope (the successor to the Hubble Space Telescope), and will also report on this ongoing work. Finally, Dr. Bos will speak briefly about career paths in physics and engineering, and how one comes to have such amazing opportunities to work on projects like the Phoenix and the Webb Telescope.
Scientific reasoning skills refer to the cognitive skills and reasoning strategies that individuals use when engaging in scientific thinking. We will report on our study of scientific reasoning skills exhibited by middle school students and present a hierarchical model of scientific reasoning strategies that describes the behavior of both children and practicing scientists.