Tech & Science
Technology and Science news from Boulder, Colorado
TWO CU-BOULDER FACULY MEMBERS WIN NATIONAL SCIENCE FOUNDATION CAREER AWARDS
Oct 20th
Two University of Colorado faculty members have received prestigious National Science Foundation Early Career Development, or CAREER awards.
Assistant Professor Nils Halverson, who holds faculty appointments in both the astrophysical and planetary sciences department and the physics department, was awarded $875,415 over five years from NSF to support detector development and data analysis for cosmic microwave background studies with the South Pole Telescope.
Cosmic microwave background is relic heat from the Big Bang that scientists can detect with microwave-wavelength telescopes. The light is slightly polarized, much in the way sunlight is polarized when it is reflected off the surface of a pond. The polarization signal is expected to contain tiny ripples from gravitational waves set in motion a small fraction of a second after the Big Bang, said Halverson.
By measuring the signal, astrophysicists can begin to understand the physics of the universe during its birth. As part of the NSF award, Halverson and astrophysical and planetary sciences instructor Seth Horenstein will provide a graduate class focused on observations, data analysis and statistics with conceptual assessment tools, peer-instruction exercises and course notes.
Assistant Professor Amy Palmer of the chemistry and biochemistry department received $831,720 from the NSF over five years to support her research to provide a powerful new approach to illuminate disease-causing bacteria like salmonella that invade host organisms and can produce harmful and sometimes lethal effects.
Many bacterial pathogens use a set of proteins called “effectors” to invade and infect host cells, cooperatively working to hijack cellular signaling and to reprogram the host cell to enable bacterial survival. Palmer and her team are developing a new method that will directly tag a broad spectrum of effector proteins with fluorescent molecules in order to visualize their movements during infection of a host cell.
Palmer’s project also will contribute to a campuswide effort to reform undergraduate science education by developing and validating interdisciplinary, hands-on tutorials that will promote student engagement and transform student learning. She has worked with the Science Education Initiative on campus, which is part of the university’s STEM efforts, to integrate learning assistants into upper division physical chemistry classes, develop pre/post concept tests to measure learning gains and to promote active engagement in the classroom. Palmer also is a faculty member in CU’s Colorado Initiative in Molecular Biotechnology, or CIMB.
SOURCE: CU MEDIA RELEASE
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CU scientists discover earlier warming period
Oct 7th
If you think global warming is bad, 11 billion years ago the entire universe underwent what might be called universal warming. The consequence of that early heating was that fierce blasts of radiation from voracious black holes stunted the growth of some small galaxies for a stretch of 500 million years.
That is the conclusion of a team of astronomers led by the University of Colorado at Boulder who used the new capabilities of NASA’s Hubble Space Telescope to probe the invisible, remote universe.
Using the newly installed Cosmic Origins Spectrograph, or COS, the team identified an era from 11.7 to 11.3 billion years ago when the universe stripped electrons off from primeval helium atoms — a process called ionization. This process heated intergalactic gas and inhibited it from gravitationally collapsing to form new generations of stars in some small galaxies. The lowest-mass galaxies were not even able to hold onto their gas, and it escaped back into intergalactic space.
CU-Boulder Professor Michael Shull of the astrophysical and planetary sciences department and his team were able to find the telltale helium spectral absorption lines in the ultraviolet light from a quasar — the brilliant core of an active galaxy. The quasar beacon shines light through intervening clouds of otherwise invisible gas, like a headlight shining through a fog. The beam allows for a core-sample probe of the clouds of gas interspersed between galaxies in the early universe.
The universe went through an initial heat wave over 13 billion years ago when energy from early massive stars ionized cold interstellar hydrogen from the Big Bang. This time period is called the Reionization Epoch because the hydrogen nuclei were originally in an ionized state shortly after the Big Bang, said Shull, also a faculty member at CU-Boulder’s Center for Astrophysics and Space Astronomy, or CASA.
A paper on the subject will be published in the Oct. 20 issue of The Astrophysical Journal. Co-authors included CASA Research Associate Kevin France, CASA Research Associate Charles Danforth, CASA postdoctoral researcher Britton Smith and Jason Tumlinson of the Space Telescope Science Institute in Baltimore.
But the Hubble data indicated it would take another 2 billion years before the universe produced sources of ultraviolet radiation with enough energy to do the heavy lifting and reionize the primeval helium that also was cooked up in the Big Bang.
This radiation didn’t come from stars, but rather from quasars, said Shull. In fact, the epoch when the helium was being reionized corresponds to a transitory time in the universe’s history when quasars were most abundant.
The universe was a rambunctious place back then, Shull said. Galaxies frequently collided and this engorged supermassive black holes in the cores of galaxies with gas falling in. The black holes furiously converted some of the gravitational energy of this mass to powerful far-ultraviolet radiation that would blaze out of galaxies. This heated the intergalactic helium from 18,000 degrees Fahrenheit to nearly 40,000 degrees.
After the helium was reionized in the universe, intergalactic gas again cooled down and dwarf galaxies could resume normal assembly. “I imagine quite a few more dwarf galaxies may have formed if helium reionization had not taken place,” said Shull.
So far Shull and his team only have one sightline from Hubble to measure the helium transition, but the COS science team plans to use Hubble to look in other directions to see if the helium reionization uniformly took place across the universe.
The $70 million COS instrument, inserted during the final Hubble servicing mission in May 2009 was designed by a team from CU-Boulder led by Professor James Green and was built primarily by Ball Aerospace & Technology Corp. of Boulder.
SOURCE: CU-BOULDER MEDIA RELEASE
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genetic roots of the vertebrate jaw can be found in the embryos of a weird jawless fish, CU study says. Could explain veterbrate shift from sifter into predation
Sep 24th
A half-billion years ago, vertebrates lacked the ability to chew their food. They did not have jaws. Instead, their heads consisted of a flexible, fused basket of cartilage.
This week, an international team of researchers led by a faculty member from the University of Colorado at Boulder published evidence that three genes in jawless vertebrates might have been key to the development of jaws in higher vertebrates.
The finding is potentially significant in that it might help explain how vertebrates shifted from a life of passive “filter feeding” to one of active predation.
“Essentially what we found is that the genetic roots of the vertebrate jaw can be found in the embryos of a weird jawless fish called the sea lamprey,” said Daniel Meulemans Medeiros, an assistant professor of ecology and evolutionary biology at CU-Boulder and lead author of the study.
Medeiros’ team included Robert Cerny, assistant professor of zoology at Charles University in Prague; Maria Cattell, a researcher in the Medeiros lab; and Tatjana Sauka-Spengler, Marianne Bronner-Fraser and Feiqiao Yu from the California Institute of Technology. Their findings were published in the Sept. 22 edition of the Proceedings of the National Academy of Sciences.
Lampreys are eel-like fish with no jaws and a “very strange skeleton compared to their cousins” with jaws, Medeiros said. But “when we looked carefully at how genes are used during the development of the lamprey head, we saw that the basic plan for a jaw is there, and that only a few genes likely had to be moved around to create full-blown jaws.”
Between jawless vertebrates — called agnathans — and vertebrates with jaws — called gnathosomes — only three genes of the 12 genes the team looked at appeared to be used differently, Medeiros said. This finding suggests that “creating a jaw in a jawless ancestor was a relatively simple matter of altering when and where these few genes are used.”
The findings support a new scenario for jaw evolution, an area that has been an open question in vertebrate evolution. Viewing the eel-like fish, “It was hard to imagine how something like that could evolve into the strong, snapping, biting, chewing jaws of a shark, fish or mammal,” Medeiros said.
Medeiros’ work is supported by a $400,000 grant from the National Science Foundation. The Caltech researchers are supported by a $393,000 grant from the National Institutes of Health. Cerny’s research stems from a grant from the Academy of Sciences in the Czech Republic.
Medeiros joined the CU faculty in 2008. He earned his doctorate from Caltech in 2003.
Clint Talbot CU news services contributed to this story