Thin is in, especially among physicists who want to create microscopic
materials for use in fiber optics, electronics, and other industries.
Scientists already have shown they can make liquid threads 10 microns
in diameter—slimmer than a strand of human hair. Assistant
physics professor Wendy Zhang believes
they can go further, suggesting in the October 29 Physical Review
Letters that smaller sizes could theoretically be achieved by manipulating
air bubbles in a process called viscous entrainment. The concept
awaits testing in the lab.
observes liquid air bubbles.
Sexual competition among males has reached a new low: it’s
evident at the molecular level. A protein regulating semen viscosity
evolves more rapidly in primate species whose females have multiple
partners, a team led by human-genetics assistant professor Bruce
Lahn reports in the December Nature Genetics and
the November 7 online edition. The protein, semenogelin, determines
the secretion’s post-ejaculation strength—from liquid
substance to solid plug, preventing fertilization by subsequent
suitors. Sequencing the semenogelin gene in a variety of primates,
the researchers found that when females are promiscuous males face
selective pressure to make their semen more potent, an adaptation
that translates into larger testicles and sperm counts.
A neck apart
Putting the terrible in “terrible-headed lizard from the Orient,”
researchers in Chicago and China have solved the mystery of how
Dinocephalosaurus orientalis got its lunch. The Triassic
Period protorosaur used its long, hose-like neck to sneak up on—and
suck up—unsuspecting prey, reports a team including Michael
LaBarbera, professor of organismal biology & anatomy
and geophysical sciences, in the September 24 Science. After studying
a 230-million-year-old fossil of the species, discovered in China’s
Guizhou province two years ago by Chinese paleontologist Chun Li,
the scientists concluded that the creature’s five-foot neck—almost
twice as long as its body—served as a lethal vacuum.
Sleep deprivation hinders appetite control, new findings have shown.
A team led by endocrinology professor Eve Van
Cauter reports in the November Journal of Endocrinology
& Metabolism that a lack of ZZZs can diminish the hormone
leptin, which tells the brain whether the body needs more food.
The researchers studied 11 healthy 22-year-old men, comparing their
leptin levels after four and eight hours of snoozing. When sleep—and
thus leptin—is in short-supply, people tend to overeat, the
team concluded. The hormone is widely thought to hold the key to
Big bang, big whoop
The big bang may not be such a big deal, according to University
physicists. Taking some wind out of the prevailing scientific theory
explaining the universe’s origin, assistant physics professor
Sean Carroll and graduate student Jennifer
Chen argue on the Cornell University Web site arXiv.org
that the world’s entropy is infinite. Previous theories have
assumed the opposite. Supposing that energy could always increase,
Chen and Carroll project that big bangs could happen repeatedly
over incredibly long periods of time. They further theorize that
a fluctuation in a preexisting universe could have set off the famous
explosion 10 to 20 billion years ago.—M.L.