Rents Push Families to Homelessness
are more likely to be driven into homeless shelters by in-creased
unemployment and by hikes in rental-housing costs than by welfare
reform or by the occurrence of substance abuse or disabilities in
heads of households. Those are the findings of a study by Dr. Dennis
Culhane, professor of social welfare policy. He and his team found
a significant association between a rise in unemployment and the
rate of families use of homeless shelters. Increases in rental housing
costs also had a direct relationship to the rate of shelter admissions,
study, published in Cityscape: A Journal of Policy and Development
Research by the U.S. Department of Housing and Urban Development,
also looked at other factors, including welfare reform.
Culhane's team used data collected by the Office of Emergen-cy Shelter
and Services, Philadelphia's central management agency for
homeless emergency services. To see if shelter utilization changed
signifi-cantly after March 1997, when major welfare reform was implemented
in PA, they looked at the number of families admitted by family
size, race, age of household head, income, household-head disability
and average length of stay. The researchers also checked these factors
after three, six, nine and twelve months of welfare-reform implementation.
researchers looked at whether an increase in shelter admittance
could be tied to an expected decline in the state welfare caseloads
as the new Temporary Assistance for Needy Families guidelines took
effect. Under TANF, lifetime benefits are capped at five years,
and those receiving benefits have two years to find employment before
being cut off.
researchers also found a small but negative relationship between
self-reported substance abuse in the household heads and shelter
admis-sion, as well as a small but positive relationship between
household heads with a disability and shelter use.
Deprivation Impairs Memory Consolidation
Scientists at Penn have found new
support for the age-old advice to "sleep on it." Mice
allowed to sleep after being trained remembered what they had learned
far better than those deprived
of sleep for several hours afterward.
researchers also determined that the five hours following learning
are crucial for memory consolidation; mice deprived of sleep five
to 10 hours after learning a task showed no memory impairment. The
results are reported in the May/June issue of the journal Learning & Memory.
consolidation happens over a period of hours after training for
a task, and certain cellular processes have to occur at precise
times," said senior author Dr. Ted Abel, assistant professor
of biology at Penn. "We set out to pinpoint the specific window
of time and area of the brain that are sensitive to sleep deprivation
Abel and his colleagues found that sleep deprivation zero to five
hours after learning appeared to impair spatial orientation and
recognition of physical surroundings, known as contextual memory.
Recollection of specific facts or events, known as cued memory,
was not affected. Because the brain's hippocampus is key to contextual
memory but not cued memory, the findings provide new evidence that
sleep helps regulate neuronal function in the hippocampus.
has been suggested that sleep serves a variety of physiological
functions, ranging from energy conservation to refreshing the immune
system," Dr. Abel said. "Another important hypothesis
is that sleep regulates neuronal function during memory consolidation.
Our findings provide support for this theory, and, by implicating
hippocampal-dependent tasks during a specific time window, we have
taken an initial step in clarifying the neural effects of sleep
Abel's co-authors are Laurel A. Graves and Allan I. Pack of
Penn's School of Medicine and Penn undergraduate Elizabeth
A. Heller. The work was supported by the NIH, the Whitehall Foundation,
the Universi-ty of Pennsylvania Research Foundation and the Mental
Retardation and Developmental Disabilities Research Center at CHOP.
'Drug Corner' Moves to Your Computer
you're hunting for illegal drugs, you don't have to leave your com-puter
desk to find them. A simple internet search will turn up dozens
of websites that let you order your drug-of-choice for home delivery.
fact, if you search for "no prescription codeine" through
one of the standard computer-search systems, the odds are almost
fifty-fifty that the first site you hit will provide an instant
opportunity to buy drugs illegally.
finding by researchers at Penn's School of Medicine was published
in the August 20 issue of the Journal of the American Medical
is unprecedented access to opiates, and it is relatively undocu-mented," said
Dr. Robert F. Forman, assistant professor of psychology in psychiatry,
principal author of the study, and a member of Penn's
Treat-ment Research Institute.
Google.com, a commonly
used computer search engine,
Dr. Forman and his Penn colleague,
Ovgu Kaynack, found that
53 of the first
100 web-page links generated by typing in the term "no prescription
codeine" were sites that offered to sell directly or indirectly
opiate medication without a prescription, and 35 of those sites
also sold barbituates, benzodiazepines, hallucinogens and other
many instances, Dr. Forman said, the only information necessary
for purchasing drugs through the sites were a shipping address and
a pay-ment method.
websites present a significant risk to public health. The uncon-trolled
access to prescription drugs can lead to an increase in addiction
and overdose deaths, and yet children preparing a report for school
may inadvertently stumble upon a portal that leads them to illegal
drugs," Dr. Forman said. "There is evidence that prescription
drug use among young people is increasing. We need to discern whether
law enforcement officials in the United States can work effectively
against drug sites that operate out of other countries, some of
which permit the sale of opiates."
Forman's work is supported by the National Institute on Drug
Abuse Clinical Trials Network.
of Solar System 'Fossils'
using NASA's Hubble Space Telescope have discovered three of the
faintest and smallest objects ever detected beyond Neptune. Each
lump of ice and rock is roughly the size of Philadelphia and orbits
just beyond Neptune and Pluto, where it may have rested since the
for-mation of the solar system 4.5 billion years ago. The objects
reside in a ring-shaped region called the Kuiper Belt, which houses
a swarm of icy rocks that are leftover building blocks, or "planetesimals," from
the solar system's creation.
study's big surprise is that so few Kuiper Belt members were
dis-covered. With Hubble's exquisite resolution, Dr. Gary Bernstein,
associ-ate professor of physics
and astronomy, and his co-workers
expected to find at least 60 Kuiper Belt members as small as 10
miles in diameter but only three were discovered.
Bernstein and his colleagues used Hubble to look for planetesimals
that are much smaller and fainter than can be seen from ground-based
telescopes. Hubble's Advanced Camera for Surveys was pointed at
a region in the constellation Virgo over a 15-day period in January
and February. A bank of 10 computers on the ground worked for six
months searching for faint moving spots in the Hubble images.
three small objects the astronomers spottedgiven the prosaic
names 2003 BF91, 2003 BG91 and 2003 BH91range in size from
15 to 28 miles and are the smallest objects ever found beyond Neptune.
At their current locations, these objects are a billion times fainter
than the dimmest objects visible to the naked eye. But an icy body
of this size that escapes the Kuiper Belt to wander near the sun
can become visible from Earth as a comet as the wandering body
to evaporate and form a surrounding cloud.
are probing the Kuiper Belt because the region offers a window on
the early history of our solar system. The planets formed more than
4 billion years ago from a cloud of gas and dust that surrounded
the infant sun. Microscopic bits of ice and dust stuck together
to form lumps that grew from pebbles to boulders to city-or continent-sized
planetesi-mals. The known planets and moons are the result of collisions
between planetesimals. In most of the solar system, all of the planetesimals
have either been absorbed into planets or ejected into interstellar
space, destroying the traces of the early days of the solar system.
now use the Kuiper Belt to learn about the history of the solar
system, much as paleontologists
use fossils to study early life.
Each event that affected the outer solar systemsuch as possible
gravitational disturbances from passing stars or long-vanished planetsis
frozen into the properties of the Kuiper Belt members that we see
the Hubble telescope could search the entire sky, it would find
per-haps a half-million planetesimals, but, if collected into a
single planet, they would be only a few times larger than Pluto.
The new Hubble observations, combined with the latest ground-based
Kuiper Belt surveys, rein-force the idea that Pluto itself and its
moon Charon are just large Kuiper Belt members. Why the Kuiper Belt
planetesimals did not form a larger planet and why there are fewer
small planetesimals than expected are questions that will be answered
with further study of the Kuiper Belt. This will help to understand
how planets might have formed around other stars as well.
new results from Hubble were reported by Dr. Bernstein and Dr. David
Trilling, Penn; Renu Malhotra, University of Arizona; Lynne Allen,
University of British Columbia; Michael Brown, California Institute
of Technology; and Matthew Holman, Harvard-Smithsonian Center for
As-trophysics. The results have been submitted to the Astronomical
Journal for publication.
Almanac, Vol. 50, No. 4, September 16, 2003