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Updated 10:30 AM January 16, 2009
 

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Scholarship & Creative Work

Shade coffee benefits more than birds

Shade coffee farms, which grow coffee under a canopy of multiple tree species, not only harbor native birds, bats and other beneficial creatures, but also maintain genetic diversity of native tree species and can act as focal points for tropical forest regeneration, researchers say.

(Photo by Shalene Jha)

Shalene Jha, a graduate student whose main interest is insects, initially wanted to find out whether shade coffee farms nurture native pollinators such as stingless bees. When she began her fieldwork in Chiapas, Mexico, she focused on a particular tree, Miconia affinis, which is pollinated by an unusual method known as buzz pollination.

In order to release pollen from its flowers, bees grab hold and vibrate their flight muscles, shaking the pollen free. Non-native species such as Africanized honeybees don't perform buzz pollination, but native bees do, Jha says, "so I thought Miconia, which requires buzz pollination and is common both in forests and on coffee farms, could be a bio-indicator of how well native bees are pollinating native plants."

With guidance from Christopher Dick, an assistant professor of ecology and evolutionary biology who studies genetic diversity patterns in tropical tree species, Jha collected and analyzed DNA samples from Miconia trees growing in a network of coffee farms and forest fragments.

By performing a genetic analysis, Jha and Dick were able to determine whether trees growing near one another were all siblings from the same mother tree or a genetically diverse assortment from multiple mothers.

The findings appear in the Dec. 23 issue of the journal Current Biology.


College students say study habits improve with ADHD drugs

Undergraduates who illegally use ADHD medication without a prescription say it's worth the risk for one key benefit: enhancing their ability to study.

More than 5 percent of students surveyed in a new study reported using Attention-Deficit/Hyperactivity Disorder medication without a prescription during the past six months. Nine percent reported doing this since they began college.

The researchers were from U-M, Duke University and University of North Carolina at Greensboro.

"The nonmedical use of prescription stimulants among U.S. college students is now at its highest level in 15 years," says expert Sean Esteban McCabe, a research associate professor at the Substance Abuse Research Center and Institute for Research on Women and Gender. The findings, he says, reinforces the researchers' previous work indicating more than 90 percent of nonmedical users in college obtain the prescription stimulants from friends.

A Web-based survey of 3,407 students was taken in spring 2007 at UNC-Greensboro and at Duke. Ninety percent of respondents who reported using the medication without a prescription during the past six months said enhancing the ability to study was the reason they most often took stimulant drugs such as Ritalin, Adderall and Concerta for nonmedical purposes. And nearly 90 percent of these students felt it was effective in helping them study.

Non-academic motives, such as "to get high," were far less common.

According to the study, which appears in the online edition of the Journal of Attention Disorders, students perceived nonmedical use to be beneficial despite frequent reports of adverse reactions.


Going outside — even in cold — improves memory, attention

While exploring the cognitive benefits of interacting with nature, researchers found that walking in a park in any season, or even viewing pictures of nature, can help improve memory and attention.

Psychology researchers Marc Berman, John Jonides and Stephen Kaplan found memory performance and attention spans improved by 20 percent after people spent an hour interacting with nature.

Researchers believe the findings could have broader impact on helping people who may be suffering from mental fatigue.

"Interacting with nature can have similar effects as meditating," Berman says. "People don't have to enjoy the walk to get the benefits. We found the same benefits when it was 80 degrees and sunny over the summer as when the temperatures dropped to 25 degrees in January. The only difference was that participants enjoyed the walks more in the spring and summer than in the dead of winter."

Kaplan and his wife, Rachel Kaplan, a researcher in psychology and the School of Natural Resources and Environment, argue that people are far more likely to be satisfied with their lives when their environment supports three basic needs: the ability to understand and explore; to feel they make a difference; and to feel competent and effective.

Berman decided to test that theory by sending study participants on walking routes around Ann Arbor. Participants walked on an urban route down main streets and also on a route in Matthaei Botanical Gardens and Nichols Arboretum. When participants walked in the Arboretum they improved their short-term memory by 20 percent, but showed no improvements after walking down city streets.

Research results appear in the December issue of Psychological Science.


Shaming some kids makes them more aggressive

Early adolescents with high self-esteem are more likely to react aggressively when they feel ashamed than their peers with lower levels of self-esteem, researchers say.

"Young teens with low self-esteem apparently don't feel the need to protect their punctured egos," says Brad Bushman, professor of psychology and co-author of the study with colleagues from VU University and Utrecht University in The Netherlands.

For the study, Bushman, Sander Thomaes and colleagues conducted an experiment with 163 children ages 10 to 13, from Michigan middle schools. Almost all were white, and slightly more than half (54 percent) were males.

A few weeks before participating in the online experiments, the young people filled out a questionnaire designed to assess their levels of self-esteem and narcissism.

The researchers measured self-esteem by assessing the degree to which participants were satisfied with themselves and the way they led their lives.

Narcissism included grandiose views of themselves, inflated feelings of superiority and entitlement, and exploitative interpersonal attitudes.

"Narcissists seem highly motivated to create and maintain a grandiose view of self," the researchers wrote. "They tend to interpret social situations in terms of how they reflect on the self, and they engage in self-regulatory strategies to protect self-esteem when they need to. As shameful situations constitute a threat to grandiosity, narcissistic shame-induced aggression can likely be viewed as defensive effort to maintain self-worth."

The researchers also found that high self-esteem increased narcissistic shame-induced aggression.

The research findings appear in the December issue of Child Development.


Medical costs lower for diabetic patients who treat gum disease

Treating gum disease in patients who have diabetes with procedures such as cleanings and periodontal scaling is linked to 10-12-percent lower medical costs per month.

The findings are encouraging but the study was not designed to firmly establish cause and effect, says George Taylor, associate professor of dentistry, who also has an appointment in epidemiology in the School of Public Health. Taylor led the research project to investigate whether routine, non-surgical treatment for gum disease is linked to lower medical care costs for people with diabetes.

In periodontal disease the body reacts to the bacteria causing the gum infection by producing proteins or chemicals called inflammatory mediators. Ulcers and open sores in the gums become passageways for these proteins and for the bacteria themselves to enter the body's blood circulation. These inflammatory mediators, as well as some parts of the bacteria, prevent the body from effectively removing glucose, or sugar, from the blood.

The higher level of blood sugar is known as poor diabetes control. Poor diabetes control leads to serious diabetes complications such as vision disorders, cardiovascular and kidney disease and amputations, among others.

"Cleanings and other non-surgical periodontal treatment remove the harmful bacteria," Taylor says. "We believe this helps prevent the body from producing those harmful chemicals that can enter the systemic circulation and contribute to poorer diabetes control."

The study showed that medical care costs decreased by an average of 11 percent per month for patients who received one or two periodontal treatment procedures annually compared to those who received none. For patients receiving three or four annual treatments, costs decreased nearly 12 percent.

Taylor's team includes: Wenche Borgnakke, senior research associate in health sciences; Michael Manz, senior research associate in health sciences; and Tammie Nahra, assistant research scientist.

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