|  Citations
Grow up already
Most Americans agree that becoming an adult is a gradual process
that culminates around age 26. That’s according to the National
Opinion Research Center (NORC), which found that today’s young
adults are reaching certain milestones about a half-decade later
than did their parents, says study author Tom
Smith, PhD’80, who directs the General Social Survey.
The report, based on in-person surveys of Americans over 18, identified
seven steps toward adulthood and the average age of expected completion.
Finishing an education, at 22.3 years, was considered most important.
The other steps, ranked in order of importance, were full-time employment
(21.2 years old), supporting a family (24.5), financial independence
(20.9), living independently of parents (21.1), marriage (25.7),
and having a child (26.2).
Photo by Mick Ellison |
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161-million-year-old salamander fossil.
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Scientists
uncover oldest salamanders
A new salamander species found in a 161-million-year-old fossil
traces the amphibian's origin to Asia. The previous oldest-known
salamander fossil, found in North America, dated back 65 million
years. Professor of Organismal Biology and Anatomy Neil
Shubin and Peking University scientists, who reported their
discovery in the March 27 Nature, found thousands of fossils
in seven Chinese excavation sites. The magnitude of fossils may
help answer how independently evolving salamander species developed
similar features.
Bipolar genes
Chicago researchers have linked bipolar disorder to the gene complex
G72/G30 on Chromosome 13. Although bipolar disorder, or manic-depressive
illness, was long thought to be inherited separately from schizophrenia,
the same gene complex previously was found to increase risk for
the latter illness. Bipolar disorder is caused by many genes and
was linked to another in 2002. The G72/G30 complex increases bipolar
disease susceptibility by about 25 percent, according to Elliot
Gershon, chair of psychiatry, and research associates Eiji
Hattori and Chunyu Liu, whose
findings were published in the May American Journal of Human
Genetics.
Climate changes
not so mild
Although many scientists focus on gradual climate change, abrupt
changes may be more typical of Earth’s history than the relatively
stable climate of the past few centuries, argued Chicago geophysical-sciences
professor Ray Pierrehumbert and ten
coauthors in the March 28 Science. Examining the chemical
composition of Greenland’s ice cores, the researchers theorized
that the gradual warming that began 10,000 years ago, after the
last ice age, was interrupted abruptly by returned glacial conditions,
which lasted for about 1,000 years. The recent climate stability
and preceding cold spell are not fully understood. Because it would
be difficult to adapt to such instability, Pierrehumbert says, it
is important to study such changes.
Plaque control
Formerly elusive plaques found in the brains of those with Alzheimer’s
disease can now be observed more closely. The plaques—made
of millions of ribbon-like peptide chains, or fibrils—may
be a cause or a symptom of the disease. Removing amino acids, a
team including Argonne chemists Roberto Botto,
David Gregory, and
P. Thiyagarajan, Chicago pathologist Stephen Meredith, PhD’82,
and former Chicago chemist David Lynn
(now at Emory) found that the truncated peptide would form fibrils
just as the whole one does. Because the resulting peptide is less
complex, scientists can study the self-assembly process and the
fibril’s structure.
—D.G.R.
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