The most detailed measurements to date of the dusty disks around young stars confirm a new theory that the region where rocky planets such as Earth form is much farther away from the star than originally thought.
These first definitive measurements of planet-forming zones offer important clues to the initial conditions that give birth to planets. Understanding planet formation is key to understanding Earth's origins, yet this remains a mysterious process, says John Monnier, assistant professor of astronomy and lead author on the paper, "The near-infrared size luminosity relations for Herbig Ae/Be disks" in a recent edition of Astrophysical Journal.
Very young stars are surrounded by thick, rotating disks of gas and dust, which are expected eventually to disappear as material is either pulled into the star, is blown from the disk, or collects into larger pieces of debris. This transition marks the leap from star to planet formation.
The scientists examined the innermost region of such disks where the star's energy heats the dust to extremely high temperatures. These dusty disks are where the seeds of planets form, where dusty particles stick together and eventually grow to large masses.
If the dust orbits too close to the star, however, it evaporates, shutting off any hope of planet formation. It's important to know where the evaporation begins since it has a dramatic effect on planet formation, Monnier says.
The attitudes and beliefs that young people have about sex may be more swayed by what they hear on television than what they see, according to a U-M researcher.
A recent study by Communications Studies graduate instructor Laramie Taylor delved into the complex relationships between sexual television content, attitudes and perceived realism. The study appeared in the May issue of The Journal of Sex Research.
People who perceived the television content to be realistic were influenced by sexual content, he says. Participants who scored highly on a perceived realism scale reported more permissive sexual attitudes after watching sexual television content.
Participants who did not think the television content was realistic were not significantly affected by its sexual messages.
Taylor also says beliefs about sexual activity were influenced by verbal but not by visual sexual content. Participants who believed that television content was realistic, and watched clips of characters discussing sex, later reported the belief that relatively more of their female peers were sexually active. They were not, however, similarly influenced by visual depictions of sex.
Since two-thirds of the study's participants were women, conclusions based on gender differences could not be made. Taylor notes that other research has indicated women and men often react differently to sexual media content.
A new study shows that children at the greatest risk for lead poisoning, and those identified with elevated blood-lead levels through screening, were the least likely to get follow-up testing needed for prevention.
In the first population-based study of its kind, researchers from the U-M Health System Child Health Evaluation and Research (CHEAR) Unit found that only more than half of the children on Medicaid with elevated blood-lead levels identified through screening got the necessary follow-up testing to prevent lead poisoning, and of those children, nearly half still had elevated blood-lead levels.
The results of the study were published in the May 11 issue of the Journal of the American Medical Association.
Screening is only one step in the process to prevent lead poisoning, which even at low levels can impair cognitive development and cause anemia, says lead author Dr. Alex Kemper, a member of the CHEAR team in the Division of General Pediatrics. Follow-up testing is the cornerstone of lead-poisoning management and an essential component of secondary prevention, he says.
Using a group of 3,682 Michigan Medicaid-enrolled children under the age of 6 with an elevated blood-lead level screening, Kemper and his team found that a little more than half (53.9 percent) of the children received follow-up testing.
In addition to Kemper, the study was co-authored by programmer analyst Lisa Cohn, research associate Kathryn Fant and research investigator Kevin Dombkowski with the CHEAR Unit.
An understanding of sleep-related problems may help doctors better diagnose and treat asthma, according to new U-M Health System (UMHS) research.
Symptoms of apneaa condition in which people stop breathing for periods of time during sleepand other breathing problems during sleep are common among people with asthma, according to the research, which was presented May 25 at the American Thoracic Society's (ATS) 2005 International Conference in San Diego.
Researchers say doctors should examine asthma patients' sleep patterns more often, especially when the patients continue to have trouble even with regular use of inhalers and other common asthma treatments.
The more doctors look for sleep apnea in patients with asthma, the more they find it, says Dr. William F. Bria II, medical co-director of the UMHS Asthma Airways Program and associate professor of internal medicine in the Medical School.
Researchers examined the connection between sleep-related breathing disorders by giving questionnaires to patients with asthma. Most participants were being treated for asthma with inhalers and other medications, but they still were symptomatic, says Dr. Mihaela Teodorescu, a pulmonary medicine specialist, research fellow in sleep medicine and a lecturer at UMHS, who presented the findings at the ATS meeting and who is leading the study.
Large percentages of the people included in the study33 percent of men and 49 percent of womenwere found to be at risk for obstructive sleep apnea.
In addition to Teodorescu and Bria, the authors are Dr. Ronald Chervin, associate professor of neurology, and director of the Sleep Disorders Center and Michael Aldrich Sleep Disorders Laboratory; Dr. Flavia Consens, clinical assistant professor of neurology; Dr. Michael Coffey, associate professor of internal medicine; Ann Durance, a clinical nurse at UMHS; Kevin Weatherwax, a project associate in neurology; John Palmisano, clinical coordinator in neurology; Peter Mancuso, assistant professor of public health; and Jesica Pedroza, a research assistant in the Undergraduate Research Opportunity Program.
Technique may allow cancer patients to freeze eggs
A new technique might allow women diagnosed with cancer the opportunity to have children when treatments rob them of their fertility, researchers at the Comprehensive Cancer Center (CCC) have found.
Cancer treatments such as chemotherapy and radiation therapy can cause damage to a woman's reproductive system and leave her unable to have children afterward.
By having her eggs frozen before she begins cancer treatments, a woman can preserve the hope of one day having a baby.
U-M researchers looked beyond traditional techniques to a method of freezing cells called vitrification. This cryopreservation technique allows the eggs to be cooled fast enough that the transformation from liquid to solid is instantaneous. No ice crystals form and the consistency resembles a viscous glassy state.
With traditional slow-freeze techniques, just over half the eggs survive the thawing process. Using vitrification, there is a 98 percent survival rate, says Gary D. Smith, associate professor of obstetrics and gynecology, urology, and molecular and integrative physiology at the Medical School, and director of the Fertility Counseling and Gamete Cryopreservation Program at CCC.
Smith presented results of his research May 29 at the World Congress on In Vitro Fertilization, Assisted Reproduction and Genetics in Istanbul, Turkey.
Older people are better at picking their battles
Older people are less likely than younger people to react aggressively when problems come up in their relationships, U-M research shows.
Older people appear better able than younger people to pick their battles, says Kira Birditt, a researcher at the Institute for Social Research. When they're upset with others, older people are more likely to do nothing or to wait and see if things improve.
One of Birditt's studies, funded by the National Institutes on Aging, appears in the May 2005 issue of the Journal of Gerontology: Psychological Sciences.
Younger people were more likely to shout, argue or walk away in response to problems. When confronted with interpersonal problems, older people reported less frequent contact with their social partners and less distress. Even after the researchers controlled for frequency of contact and distress levels, the age differences in reactions to conflict remained.
The reason may be that older people mellow as they age and value their relationships more, instead of becoming grumpier and more like the stereotypical curmudgeons. Or it may be that today's older adults have better manners than younger people, Birditt speculates, and therefore are less likely to yell and scream when someone upsets them.
Exposure to gun violence boosts odds of teens acting violently
Exposure to gun violence makes adolescents twice as likely to perpetrate serious violence in the next two years, according to a University researcher.
Jeffrey Bingenheimer, a doctoral student in health behavior and health education, analyzed five years of data from adolescents living in 78 neighborhoods in Chicago. Bingenheimer is lead author on a paper in the journal Science.
Using a statistical method called propensity stratification, Bingenheimer and co-authors Robert Brennan and Felton Earls of Harvard University aimed to establish a firm cause-and-effect relationship between exposure to gun violence and later perpetrating violence.
Overall, Bingenheimer found that adolescents exposed to firearm violence were nearly four times as likely as unexposed adolescents to perpetrate violence during the next two years.
The study defined exposure to firearm violence as having been shot or shot at or seeing it happen to someone. It defined perpetrating violence as carrying a hidden weapon, attacking someone with a weapon, shooting someone, shooting at someone, or being in a gang fight.
State should keep the Single Business Tax, but with changes
Michigan should consider alternatives that maintain the state's Single Business Tax (SBT) in slightly modified form, rather than scrapping it altogether, says a business school economist.
The SBT as originally conceived offered efficient investment incentives, a counter-cyclical revenue stream and tax burdens that fell on economic rents, says James Hines, professor of business economics at the Stephen M. Ross School of Business. While in practice the SBT does not promote efficiency as cleanly as it does in theory, the attractive features of the SBT compare favorably to those of leading corporate income tax alternatives.
According to Hines, the Michigan legislature adopted the SBT in 1975 during a severe budget crisis in hopes the new tax would generate an additional $200 million immediately and, over the long term, provide a stable source of tax revenue, encourage capital investment and make tax administration easier. Unlike the corporate income tax or dizzying array of supplemental taxes used by other states, the SBT is a value-added tax levied at a current rate of 1.9 percent on adjusted gross receipts.
The original concept behind the SBT was to encourage business investment in the state by permitting firms to deduct 100 percent of investment expenditures from taxable income, he says. Over the years, the SBTwhich is unique to Michiganhas come under increasing attack for the tax burden it imposes on the state's businesses, particularly companies that are losing money, Hines says.
Nature abounds with examples of bacteria that can thrive in extreme situationssurviving on toxic chemicals, for instance.
In a paper published online in the Journal of the American Chemical Society May 25, U-M researchers show how some bugs manage to do that: by harnessing other potentially harmful chemicals known as free radicals to degrade the toxins they live on.
Such insights could lead to new ways of engineering bacteria to clean up environmental messes, says Associate Professor of Chemistry E. Neil Marsh, who did the work with postdoctoral fellow Chunhua Qiao.
Free radicalshighly reactive chemical species that have been implicated in aging, diseases such as Alzheimer's and cancer, and even destruction of the ozone layeraren't all bad, Marsh says.
Bacteria such as T. aromatica hold promise for use in cleaning up environmental pollutants because they not only break down hazardous chemicals, but they can do it underground, in oxygen-scarce environments.
IT professionalsForget experience, get an MBA
Experience in the world of information technology pays off, but having a master's degree in business earns an even fatter paycheck for IT professionals, according to a new study at the Stephen M. Ross School of Business.
IT executives with MBA degrees command higher salaries than their peers with comparable years of on-the-job IT experience, the study shows. Overall, compared to firms in other U.S. industries, IT companies pay a significant premium to attract and retain these highly prized professionals.
Ever-increasing competitive intensity is fueling the demand for executives with a good grounding in managerial competencies for applying technology in a given business context, says M.S. Krishnan, professor of business information technology.
In the study, Krishnan and Ross School graduate student research assistant Sunil Mithas examined total annual compensation for more than 55,000 IT professionals, including senior and middle-level executives, in the United States for the period 1999-2002.
Their findings show that the labor market values IT professionals with an MBA degree much more than IT professionals without an MBA. Two extra years of IT experience yields a salary advantage of 2.8 percent (1.4 percent annually), but a two-year MBA degree provides a salary advantage nearly three times greater8.2 percent.