Scholarship & CreativityFloating pile of rubble a pristine record of solar system's history
A small, near-Earth asteroid named Itokawa is just a pile of floating rubble, probably created from the breakup of an ancient planet, according to a University researcher who was part of the Japanese space mission Hayabusa.
The finding suggests that asteroids created from rubble would provide pristine records of early planet formation.
Daniel Scheeres, associate professor of aerospace engineering, was a member of the team that determined the asteroid's mass, surface environment and gravitational pull, and helped interpret the images that were taken of the asteroid from the spacecraft. Some of the findings are discussed in a special June 2 issue of the journal Science. The mission is led by the Japan Aerospace Exploration Agency.
The Hayabusa space probe arrived at asteroid Itokawa last fall and orbited for three months. During that time it descended twice to the surface of the asteroid, named for the father of Japanese rocketry, to collect samples. In 2010 the probe will return to Earth and eject a sample canister that will reenter the atmosphere and land in central Australia. Researchers hope this will be the first asteroid sample brought back to Earth.
Scheeres says that the confirmation of Itokawa's makeup as rubble rather than a single rock has large implications for theories of how asteroids evolved, and will lead to a better understanding of the early solar system. Asteroids are thought to be the remnants of material that formed the inner planets, which include Earth, and could bear the record of events in the early stages of planet formation.
Knowing if an asteroid is a single, big rock or a pile of rubble will have a major influence on how to nudge it off course, Scheeres says, should its orbit be aimed at Earth.
Adult children of mothers with mental illness show problems
Mothers with serious mental illness report that, for the most part, their children entered adulthood with psychiatric and behavioral problems.
It is possible that these children would have been helped by an early intervention with the troubled parents, says Daphna Oyserman, a professor of social work and psychology, and a research professor in the Institute for Social Research.
In Oyserman's survey of mothers with mental illness, they reported that one-third of their adult children had not completed high school and about one-third experienced psychological problems. It also might be inferred that the adult children in this study had relationship problems, because at an average age of 22, only about one in nine were in a committed relationship, although 38 percent were parents.
"Because of the stigma attached to mental illness, parents may not ever share the fact that they have a mental illness with their children. This means that even years later, adult children may not have an explanation for parental behavior," says Oyserman. The study appears in the May issue of Health and Social Work.
From a larger study of 379 mothers with serious mental illnesses, 157 mothers with an adult child between the ages of 18 and 30 responded via telephone interview about frequency of contact with their adult children, satisfaction with the relationship, their adult child's education, attainment of other adult roles and problems. Mothers reported that about half (54 percent) of adult children had a major problem in psychological, drug or alcohol or legal domains. Although nearly 40 percent of adult children were parents themselves, only about 12 percent were in a committed relationship. Mothers' bipolar diagnosis was a significant predictor of how many problems adult children were reported to have.
The study's other researchers were professors Carol Mowbray (deceased), School of Social Work at U-M, and Deborah Bybee, Department of Psychology at Michigan State University; graduate student Peter MacFarlane of Ohio State University; and research assistant Nicholas Bowersox of Marquette University.
New analysis of networks reveals surprise patterns in politics, the Web
A new computer analysis technique developed at U-M that separates networks into communities yielded some surprises when used on real-world networks like political books, blogs and metabolic systems.
For instance, researchers used the algorithm to sort books sold on Amazon.com into left- and right-wing groups, and they found the book most appealing to conservatives was written by Democrat Zell Miller.
Miller, the former governor of Georgia and U.S. senator, angered Democrats by endorsing George Bush during the last presidential election. Miller's book, "A National Party No More, The Conscience of a Conservative Democrat," was the book most central to the community of conservative book buyers, according to researchers.
A network is a system of nodes connected by links, and the nodes sometimes divide into groups or communities, says physics associate professor Mark Newman, who developed the technique. By analyzing these groups, scientists better understand the structure and function of the network. The technique performs it faster and more accurately than other methods, Newman says. It also adds a new element to the analysis in that it weighs how tightly members are bound to their groups, which can affect their functions or the roles that they play.
Newman's methods also have been adapted by researchers working in molecular biology to study metabolic networks, the chemical systems that power cells in human and animal bodies. Newman's findings were to appear in the
Substance abuse screening may help teenage trauma patients curb risky behavior
Researchers at the U-M Health System (UMHS) believe one way to help curb such risky behavior is to do drug screening for all hospitalized pediatric trauma patients, and offer brief alcohol and substance abuse intervention programs to those who test positive.
Their study revealed that nearly 40 percent of the pediatric trauma patients ages 14-17 screened for substance abuse tested positive. Of those patients, 29 percent were for opiates including opium or heroin, 11.2 percent for alcohol and 20 percent for cannabis, or marijuana.
These findings, published in the May issue of the Journal of Pediatric Surgery, support the value of routine substance abuse screening for all injured teenage hospital patients regardless of age, gender or type of injury, says study lead author Dr. Peter F. Ehrlich, clinical associate professor, Department of Pediatric Surgery at the U-M Medical School.
As a Level 1 pediatric trauma center, routine drug screening for all injured patients ages 14 to 17 is part of the UMHS trauma protocol. Indeed, according to the National Institute on Alcohol Abuse and Alcoholism, trauma centers are an ideal site for alcohol screening and brief intervention programs. Previous studies have proven the cost-effectiveness for such programs, with health care savings of $3.81 for every $1 spent for screening and intervention.
"To really make an impact on the care of these adolescents, drug screening cannot be performed selectively and irregularly," Ehrlich says. "So we need to take the opportunity when adolescent patients are in our care to intervene and help prevent risk-taking behavior that may lead to future injury or even death."
Along with Ehrlich, co-authors from the Department of Pediatric Surgery were Dr. Joanna K. Brown, house officer, and Robert Drongowski, senior research associate.
Katrina aftermath shows importance of environmental justice studies
National level environmental inequality studies fail to reflect the disproportionately high number of minorities and poor people living near toxic waste facilities, say the co-authors of a new study.
This shortcoming, they contend, stems from the failure of a widely used approach for assessing disparities in the distribution of environmental hazards to adequately account for the proximity between such sites and nearby residential populations.
In an article appearing in the May 2006 issue of Demography, Paul Mohai of U-M and Robin Saha of the University of Montana report that when they use alternative distance-based methods to analyze the racial and socioeconomic disparities around the nation's hazardous waste facilities, those disparities are far greater than when the traditional measuring method is applied.
The traditional method used for determining the demographics of those living near hazardous waste sites has been to examine the demographics of only those geographic unitsZIP code areas or census tractscontaining the sites.
Not taken into account was the exact location of the hazards within the ZIP code areas, or census tracts hosting the hazardous sites or the proximity of the hazards to nearby units. "Using the traditional method, if I lived right across the street from a hazardous site but fell into a different ZIP code or census tract area, the location of my home would be considered the same as the home of someone living 100 miles from the site," Mohai says.
Mohai is professor of natural resources in the School of Natural Resources and Environment and a faculty associate in the Survey Research Center at the Institute for Social Research. Saha is a former post-doctoral fellow at Michigan and currently is assistant professor of environmental studies at the University of Montana. Their research paper is titled "Reassessing Racial and Socioeconomic Disparities in Environmental Justice Research."
There's a reason some annual reports are difficult to readthey're hiding something, says a U-M business professor.
A new study by Feng Li, assistant professor of accounting at the Ross School of Business, shows that annual reports of firms with lower earnings are harder to read.
"Consistent with the motivation behind the plain English disclosure regulation of the Securities and Exchange Commission, managers may be opportunistically choosing the readability of annual reports to hide adverse information from investors," Li said. "Firms with lower earnings not only tend to file annual reports that are more difficult to read, but a decrease in earnings from the previous year also results in annual reports that are harder to read, compared with the previous year's reports."
Using a sample of more than 55,000 firm-years since 1994, Li measured annual report readability by examining syllables per word and words per sentence in companies' 10-K filings. He used two statistical readability measures: the Fog Index, which indicates the number of years of formal education a reader of average intelligence would need to read and understand the text; and the Kincaid Index, which rates text on a U.S. grade-school level.
According to the study, profits of firms with annual reports that are more difficult to read are less persistent in the next one-to-four years. In fact, companies use more complex language in their annual reports even when presenting good newsif it is only fleeting. On the other hand, Li found no significant evidence that firms make annual reports harder to read to hide more persistent bad news.
Li's research also found that larger companies and growth firms tend to have annual reports that are more difficult to read. In addition, annual reports with more negative special items are harder to read.
Industries with annual reports most difficult to read include insurance, health services and electric, gas and sanitary services. Those that are easier to read belong to the airlines and the stone, clay, glass and concrete products industries.
If all drivers were polite, they would get where they're going more quickly
Craig Davis, a retired Ford Motor Co. research scientist and current adjunct professor at U-M, studied highway merging to see how current on-ramp traffic meter systems could be made more effective. Currently, meter systems try to improve traffic flow by letting a certain number of cars enter the highway each minute based on how many already are there. Traffic metering has been around for a long time and many large U.S. cities have such systems, Davis says.
Davis says there are two basic types of traffic congestion: gridlock jams where cars stop, and the synchronous flow-type congestion, where two or more lanes of traffic all slow down to the same speed. Synchronous flow happens often near on-ramps when cars don't give one another enough room to merge, or when too many cars are on the road.
Metering systems use computer algorithms to try to predict when a jam may occur, typically based on occupancy. Davis found that traffic jams happen when throughput exceeds about 1,900 cars per hour per lane, and after that capacity drops by 10 percent or more.
Davis says in the absence of metering systems, simple politeness would go a long way toward thinning the sludgy traffic near on-ramps. But, letting people merge is helpful only if you don't slow down too much to do so. If you can safely move over a lane and allow a vehicle merge, that is even better, he adds.
Cormorant management may be unwarranted in Great Lakes
Active cormorant management and possible control strategies have been considered in response to growing concern over the marine diving birds' consumption of sports or aquaculture fish.
However, a University study conducted in 1995 to examine the predatory impact of double-crested cormorants in Lake Huron revealed the water birds did not consume enough yellow perch that year to affect the fish population. These findings, published this month in the Journal of Great Lakes Research, led researchers to conclude that cormorants posed little threat to fisheries in the Great Lakes, thereby making control measures unnecessary.
"This study indicates that cormorant predation on perch in 1995 was not substantial, compared to other mortality sources," say study authors, James Diana, Susan Maruca and Bobbi Low of the School of Natural Resources and Environment (SNRE). "Angling was not a significant source of perch mortality that year either, suggesting that natural mortality, including predation by 'piscivorous' fish (e.g., burbot, northern pike and splake) is substantial."
The researchers studied changes in cormorant and yellow perch populations in Les Cheneaux Islands of northern Lake Huron. The number of yellow perch has been declining throughout the Great Lakes for several decades, partly as a result of over-fishing in earlier years. The enactment of a 175-mm minimum size limit in 1987, intended to reduce mortality for smaller fish, has not helped the fishery. During this time, cormorants became increasingly populous in the area. In 1980, the birds became reestablished at St. Martins Shoal, just west of Les Cheneaux Islands, and by 1995, they numbered approximately 4,000 breeding pairs plus an estimated 2,000 to 8,000 juveniles. Since 1995, the number of cormorants appears to have stabilized at approximately 4,200 nests in recent years.
Study results show cormorants were much more likely to consume perch during the spawning period than at other times, although most of the fish consumed were too small to spawn. Yellow perch constituted 48 percent of the biomass of cormorant diet during spring, then dropped substantially during summer, and later rose again to 14 percent during late summer. The researchers estimated between 270,000 and 720,000 individual perch were consumed, with a best estimate of 470,000 perch age 1 and older. The population was estimated to be 9.8 million.
Diana is associate dean and professor of natural resources, and Low is professor of natural resources. Maruca graduated in 1997 and now works for SimBiotic Software Inc. in Ithaca, New York.
Scientists at the Medical School have identified biochemical signals that attract pathogenic cells to damaged lung tissueone of the first steps in a chain of events leading to a lethal disease called idiopathic pulmonary fibrosis or IPF.
Idiopathic pulmonary fibrosis is a progressive disease that kills 40,000 Americans each year. Exposure to toxic environmental agents like beryllium and silica dust can trigger IPF, but in most cases, its cause remains a mystery.
"The disease is devastating to the patients who have it, and to the physicians who have no effective ways to treat it," says Dr. Bethany B. Moore, an assistant professor of internal medicine at the Medical School. Working with Dr. Galen B. Toews, professor of internal medicine and chief of pulmonary and critical care medicine, and other Medical School researchers, Moore studies the cells and signaling pathways involved in IPF.
By learning more about the basic mechanisms of the disease, scientists hope to uncover new information that could lead to therapeutic drugs to block progressive lung damage or diagnostic tests to make early detection possible.
In earlier research, Moore discovered that a receptor molecule called CCR2 must be present on a fibrocyte's surface, in order for fibrosis to begin. Laboratory mice without the CCR2 molecule were unable to attract fibrocytes and did not develop pulmonary fibrosis after lung injury.
When Moore transferred fibrocytes containing the CCR2 receptor into healthy mice, the mice developed more severe fibrosis after lung injuries than those that did not receive the fibrocyte transplant.
"We may not be able to stop the initial disease process, but perhaps we could keep it from progressing so rapidly," Moore added.
Her research is funded by the National Heart, Lung and Blood Institute of the National Institutes of Health, the Coalition for Pulmonary Fibrosis Foundation, and the Martin Edward Galvin Fund for Idiopathic Pulmonary Fibrosis Research.