gscnews

GSC Photo Contest

Research - microscopic to telescopic imaging
Where Your Research Takes You - Caltech or in the field

In their experiment, the researchers presented six volunteers with four types of ambiguous stimuli (bistable percepts). Three were visual--including the Necker cube--and one was auditory (a sound that could be interpreted as either a single tone or two separate ones). The volunteers viewed or listened to the stimuli--and pressed a key on a keyboard when a perceptual shift occurred-- when the Necker cube flipped from inverted to outward, for example, or back again. At the same time, infrared eye-tracking software measured the diameter of the subjects' pupils.

The scientists found a significant increase in the diameter of the pupil at the instant preceding the perceptual switch. The pupil, which is about 2 mm wide in bright light, dilated by as much as 1 mm at that moment--a change that, in theory, could be noticeable to a casual observer. Koch and his colleagues also found that the more the pupil dilated, the longer the period of time before the switch from one interpretation to the other

The paper, "Pupil dilation reflects perceptual selection and predicts subsequent stability in perceptual rivalry," was published in the early online edition of the Proceedings of the National Academy of Sciences.

New Technique Makes Tissues Transparent

But humans, of course, are not remotely diaphanous. "The reason a person is not transparent is that their tissues are highly scattering," sending light waves careening through the tissue instead of straight through, as they would through the tissue of that jellyfish, explains Changhuei Yang of the California Institute of Technology.

While this scattering makes us opaque, it is well known that light scattering in a material is not exactly a random and unpredictable process. The process is even reversible; if the individual photons of light that scattered through the tissue could be collected and sent back through the tissue, they'd bounce back along the same path and converge at the original spot from which they were sent. "The process is similar to the scattering of billiard balls on a pool table. If you can precisely reverse the paths and velocities of the billiard balls, you can cause the billiard balls to reassemble themselves into a rack," Yang explains.

Their technique, called turbidity suppression by optical phase conjugation (TSOPC), is surprisingly simple. The scientists used a holographic crystal to record the scattered light pattern emerging from a 0.46-mm-thick piece of chicken breast. They then holographically played the pattern back through the tissue section to recover the original light beam. "This is similar to grabbing hold of the direction of time flow and turning it around; the time-reversed photons must retrace their trajectories through the tissue," Yang says. "The task is formidable though, as this is comparable to starting with a rack of 10 to the 18th power billiard balls (or photons), scattering them around the table, and attempting to reassemble them into a rack."

Programming Biomolecular Self-Assembly Pathways

The team invented a versatile DNA motif with three modular domains that can be made to interact with complementary domains in other species of the same motif. Rewiring these relationships changes the dynamic function of the system. To make it easier to design such systems, the researchers developed a graphical abstraction of the motif that can be used to write "molecular programs." As described in the January 17 issue of the journal Nature, the team experimentally demonstrated the execution of four such programs, each illustrating a different class of dynamic function.

As Pierce describes it, these results take them closer to achieving a long-term goal of creating a "compiler for biomolecular function"--an automated design tool that takes as input a molecular program and provides as output a set of biomolecules that execute the desired function. He remarks, "It's about time for the stone age of molecular compilers to begin."

Artlife: BCAM

Merrielle Spain

The $56-million Broad Contemporary Art Museum (BCAM) has opened at LACMA. It mainly contains pieces from LACMA (and Caltech) trustee/donor Eli Broad and his wife, Edythe, and is the museum's first home/large push for contemporary art. However, you probably want to wait--throughout February, visiting BCAM requires a timed ticket.

Schlinger Laboratory Construction

The four-story building, which will occupy 60,000 square feet, was designed by Bohlin Cywinski Jackson, a Pennsylvania-based architectural firm that has won many awards and built numerous academic and lab structures. The Schlinger Lab, which will likely merit a silver rating under the Leadership in Energy and Environmental Design (LEED) Green Building Rating System for environmentally sustainable buildings, will be constructed at a cost of $45 million and should be finished in 18 months. It will be located near the western end of the San Pasqual walkway on campus.

The Schlinger Lab was named in recognition of a $20 million campaign donation from Warren and Katharine Schlinger, whose roots run deep at Caltech. Warren spent 12 years at the Institute, earning his BS in applied chemistry, then an MS and PhD in chemical engineering, followed by postdoctoral research and teaching. Katharine grew up in the Pasadena area and was a vocal soloist, and met her husband while working as a department secretary for chemical engineering. "The new laboratory will be central to the future of the division, and it's especially fitting that our friends Warren and Katie Schlinger have played the key role in bringing it to life," says David Tirrell, chair of the Division of Chemistry and Chemical Engineering at Caltech.

Financier Munger Gives DuBridge Lecture

Originally from Omaha, Nebraska, Munger, 84, is vice chairman of Omaha-based Berkshire Hathaway Corporation, the diversified investment corporation chaired by Buffett.

Munger is known for his simple, yet wise, approach to business and investment. "We have three baskets for investing: yes, no, and too tough to understand." Thus, pharmaceuticals and technology don't make the cut, but Costco Wholesale Corporation and Geico Insurance do.

The Lee A. DuBridge Distinguished Lecture series brings prominent speakers of national and international importance to the Caltech campus. The series was inaugurated in 1996 in honor of Lee A. DuBridge, president of Caltech from 1946 to 1969. DuBridge, who died in 1994, was once called America's "senior statesman of science" by Time magazine, and was considered an exemplary research-university president in an era of vast scientific, societal, and educational change. He guided the growth of the modern Caltech while maintaining an understanding and interest in national affairs that was rare among university presidents. Previous DuBridge speakers include Buffett, Walter Cronkite, John Hume, Jack Valenti, and Judy Woodruff.

What's Wrong with Scientific Publishing? -- Opening Peer Review

Daniel Taylor

Professor R. Preston McAfee presented a process enlightened view of peer-review in which the Editor in Chief, the most responsible and accountable and informed by reviewers, simply accepts or declines papers. This is probably the lowest overhead version of peer-review: One knowledgeable person with an objective for the journal makes the up or down decision. This type of review process puts the onus on the author to make the submission as good as possible. There will be no second try. The Editor in Chief's name is attached to the quality of the papers he/she can attract and select and therefore he/she has a peer-reputation to uphold. This model does seem to harken back to some of the most legendary scholarly journals that bore the name of the "Editor", e.g. Justus Liebig's Annalen and Wilhelm Roux's Archives in Microbiology. This model is well supported by network technology. One wonders whether cost-effective publishing models will only be within the purview of the economists.

Professor John Seinfeld described Atmospheric Chemistry and Physics' two-stage publication process. Papers passing a rapid access peer-review are immediately published on the ACP Discussions website where they are open to interactive public discussion. In the second stage the peer-review process is completed and accepted, revised papers are published in ACP. Professor Tapio Schneider commented on serving as a reviewer for open peer review journals of the European Geosciences Society, mentioning the highly variable quality and utility of the open reviews. Schneider also noted that a form of open review dates back at least a couple of centuries in the documentation and publication of learned audience feedback along with some published proceedings, sometimes to the subsequent embarrassment or detriment of the learned audience respondent.

Extensive Q&A with the audience of approximately 60 Techers probed the pros and cons of these and other innovative publishing ventures. (See Nature's subsequent short essay on peer-review Š and the many subsequent blog comments -- for extensive discussion of some of the issues raised in the January 24 panel presentation: http://blogs.nature.com/peer-to-peer/2008/02/working_doubleblind.html).

At least one more event in the What's Wrong series is anticipated this academic year; comments and suggestions are encouraged at library@caltech.edu.

Harvard votes for open access to scholarly articles

In proposing the legislation, Stuart M. Shieber, a professor at FAS, said, "There is no question that scholarly journals have historically allowed scholars to distribute their research to audiences around the world. But, the scholarly publishing system has become far more restrictive than it need be. Many publishers will not even allow scholars to use and distribute their own work. And, the cost of journals has risen to such astronomical levels that many institutions and individuals have cancelled subscriptions, further reducing the circulation of scholars' works."

Harvard will take advantage of the license by hosting FAS faculty members' scholarly articles in an open-access repository, making them available worldwide for free. The faculty member will retain the copyright of the article, subject to the University's license. The repository contents can be made widely available to the public through such search engines such as Google Scholar. Faculty members may request a waiver of the license for particular articles where this is preferable. The new legislation does not apply to articles completed before its adoption.