(Press-News.org) WASHINGTON, D.C., November 21, 2010 -- For centuries, hunters have imitated their avian prey by whistling through their fingers or by carving wooden bird calls. Now a team of physicists at Harvard University in Cambridge, Massachusetts, has reproduced many of the characteristics of real bird song with a simple physical model made of a rubber tube.
"We wanted to know if you [could] build a simple device, which has minimal control but reproduces some non-trivial aspects of bird song," says L Mahadevan, a professor at Harvard. The work is being presented today at the American Physical Society Division of Fluid Dynamics meeting in Long Beach, CA.
Bird song -- a complex sound full of intricate patterns and rich harmonics -- has long been studied by neuroscientists. Their research has explained much about how young birds learn these songs from adults and the complex neurological changes that allow them to control their voices.
But Aryesh Mukherjee, a graduate student in Mahadevan's laboratory, suggests that this neural control need not be as complicated as it could be. He suspects that the physics of a bird's vocal tract could explain much of the complexity of its voice, even with relatively simple neural control.
His bird call device consists of an air source, which creates a flow through a stretched rubber tube (modeled after a bird's vocal tract), and a linear motor that presses on the tube in a fashion analogous to a contracting muscle.
"Using this very simple device that pokes a tube, I see these beautiful sounds being produced without a sophisticated controller," says Mukherjee.
When analyzed on a spectrogram, the harmonics and other characteristics of the sounds made by the physical model closely resemble the songs of a zebra finch.
Another researcher in the lab, Shreyas Mandre, now an assistant professor at Brown University, is building mathematical models that seek to capture some of the underlying principles. His model, which represents the voice as a stretched string with dampened vibrations, creates digital bird calls that are also very similar to the real thing.
"Once we understand the physics better, we'll be able to mimic the sound much better," says Mandre.
The principles underlying the models aren't limited to single species of birds. The researchers believe that -- with a few tweaks -- their models could mimic a variety of bird calls.
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The presentation, "Bird song: in vivo, in vitro, in silico" is at 9:18 a.m. on Sunday, November 21, 2010 in the Long Beach Convention Center Room: 202A. ABSTRACT: http://meetings.aps.org/Meeting/DFD10/Event/132278
MORE MEETING INFORMATION
The 63rd Annual DFD Meeting is hosted this year by the University of Southern California, California State University Long Beach, California Institute of Technology, and the University of California, Los Angeles.
It will be held at the Long Beach Convention Center, located in downtown Long Beach, California. All meeting information, including directions to the Convention Center is at: http://www.dfd2010.caltech.edu/
USEFUL LINKS
Main meeting Web site:
http://www.dfd2010.caltech.edu/
Search Abstracts:
http://meetings.aps.org/Meeting/DFD10/SearchAbstract
Directions to Convention Center:
http://www.longbeachcc.com/
PRESS REGISTRATION
Credentialed full-time journalist and professional freelance journalists working on assignment for major publications or media outlets are invited to attend the conference free of charge. If you are a reporter and would like to attend, please contact Jason Bardi (jbardi@aip.org, 301-209-3091).
ONSITE WORKSPACE FOR REPORTERS
A reserved workspace with wireless internet connections will be available for use by reporters in the Promenade Ballroom of the Long Beach Convention Center on Sunday, Nov. 21 and Monday, Nov. 22 from 8:00 a.m. to 5:00 p.m. and on Tuesday, Nov. 23 from 8:00 a.m. to noon. Press announcements and other news will be available in the Virtual Press Room (see below).
VIRTUAL PRESS ROOM
The APS Division of Fluid Dynamics Virtual Press Room will be launched in mid-November and will contain dozens of story tips on some of the most interesting results at the meeting as well as stunning graphics and videos. The Virtual Press Room will serve as starting points for journalists who are interested in covering the meeting but cannot attend in person. See: http://www.aps.org/units/dfd/pressroom/index.cfm
GALLERY OF FLUID MOTION
Every year, the APS Division of Fluid Dynamics hosts posters and videos that show stunning images and graphics from either computational or experimental studies of flow phenomena. The outstanding entries, selected by a panel of referees for artistic content, originality and ability to convey information, will be honored during the meeting, placed on display at the Annual APS Meeting in March of 2011, and will appear in the annual Gallery of Fluid Motion article in the September 2011 issue of the American Institute of Physics' journal, Physics of Fluids.
This year, selected entries from the 28th Annual Gallery of Fluid Motion will be hosted as part of the Fluid Dynamics Virtual Press Room. In mid-November, when the Virtual Press Room is launched, another announcement will be sent out.
ABOUT THE APS DIVISION OF FLUID DYNAMICS
The Division of Fluid Dynamics of the American Physical Society (APS) exists for the advancement and diffusion of knowledge of the physics of fluids with special emphasis on the dynamical theories of the liquid, plastic and gaseous states of matter under all conditions of temperature and pressure. See: http://www.aps.org/units/dfd/
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WASHINGTON, D.C., November 21, 2010 -- Hummingbirds rank among the world's largest and most accomplished hovering animals, but how do they manage it in gusty winds?
A team of researchers at New Mexico State University, Los Alamos National Laboratory, Technische Universiteit Eindhoven, and Continuum Dynamics Inc. has built a robotic hummingbird wing to discover the answer, which they describe today at the American Physical Society Division of Fluid Dynamics (DFD) meeting in Long Beach, CA
Hummingbirds do not fly like other birds, whose wings flap up and down, explained ...
WASHINGTON, D.C., November 21, 2010 -- Jump ropes are used by kids for fun and by athletes for training. But what about the underlying physics? How do jump ropes work? Can important engineering principles be studied?
Jeff Aristoff and Howard Stone of Princeton University have built themselves a robotic jump rope device that controls all the rope parameters -- rope rotation rate, rope density, diameter, length, and the distance between "hands." They capture the motion of the ropes by high-speed cameras, one to the side and one at the end. Then they compare the observed ...
WASHINGTON, D.C., November 21, 2010 -- Magnetic resonance imaging (MRI), a medical imaging technology used to image organs and soft tissues, may hold the key to improving the efficiency of jet engines, according to Lt. Colonel Michael Benson, a Ph.D. student in Mechanical Engineering at Stanford University.
In only a few hours, an MRI collects as much three-dimensional data on flow and mixing as conventional methods that take two or more years of intensive measurement. This promises to slash the time needed to develop and test new designs that improve efficiency and ...
WASHINGTON, D.C., November 22, 2010 -- From a baby's first blurted "bowl!'" for the word "ball" to the whispered goodbye of a beloved elder, the capacity for complex vocalizations is one of humankind's most remarkable attributes -- and perhaps one we take for granted most of our lives.
Not so for people who are afflicted with paralysis to their vocal folds and who suffer the social stigma of affected speech. Nor so for engineering professor Michael Plesniak and post-doctoral researcher Byron Erath at the George Washington University (GWU) Biofluid Dynamics Laboratory ...
WASHINGTON, D.C., November 21, 2010 -- A milestone in the history of renewable energy occurred in the year 2008 when more new wind-turbine power generation capacity was added in the U.S. than new coal-fired power generation. The costs of producing power with wind turbines continues to drop, but many engineers feel that the overall design of turbines is still far from optimal.
New ideas for enhancing the efficiency of wind turbines are being presented this week at the American Physical Society Division of Fluid Dynamics meeting in Long Beach, CA.
One issue confronting ...
SAN ANTONIO, Texas (Nov. 21, 2010) — What prompts normal cells to transform themselves into cancerous cells? Researchers from Texas institutions, including the UT Health Science Center San Antonio, have identified factors in the very first step of the process and reconstituted this first step in the test tube. The latter accomplishment was reported Sunday [Nov. 21] in the top-tier journal Nature Structural & Molecular Biology.
The DNA molecule — the elegant, twin-stranded necklace of life in all cells — gets broken and repaired all the time. Breaks are caused by the body's ...
Global carbon dioxide (CO2) emissions – the main contributor to global warming – show no sign of abating and may reach record levels in 2010, according to a study led by the University of Exeter (UK).
The study, which also involved the University of East Anglia (UK) and other global institutions, is part of the annual carbon budget update by the Global Carbon Project.
In a paper published today in Nature Geoscience, the authors found that despite the major financial crisis that hit the world last year, global CO2 emissions from the burning of fossil fuel in 2009 were ...
(Boston) - Scientists have discovered 30 new genes that control the age of sexual maturation in women. Notably, many of these genes also act on body weight regulation or biological pathways related to fat metabolism. The study, which appears in Nature Genetics, was a collaborative effort by the international ReproGen consortium, which included 175 scientists from 104 worldwide institutions, including Boston University School of Medicine (BUSM) and Boston University School of Public Health.
Menarche, the onset of first menstruation in girls, indicates the attainment of ...
Researchers at King's College London's Department of Twin Research have discovered, as part of a large international consortium, 30 new genes that control the age of sexual maturation in women, the Journal Nature Genetics publishes today.
Many of these genes are also known to act on body weight regulation or biological pathways related to fat metabolism. This large new study of more than 100,000 women from Europe, US and Australia highlights several specific genetic links between early puberty and body fat.
Puberty in women normally occurs between 11 – 14 years of ...
A new study challenges the current staging system that determines the extent or severity of prostate cancer that has not metastasized. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the study found that there is no link between localized prostate cancer's clinical stage and a patient's risk of cancer recurrence after having his prostate removed.
One of the primary purposes of staging prostate cancers is to help physicians determine a patient's prognosis. For example, a more advanced clinical stage should indicate a higher risk ...
