Discoveries
CO2 Reconsidered
Rising levels of carbon dioxide (CO2) in Earth’s atmosphere, which are associated with global climate change, actually appear to help counteract loss of biodiversity due to nitrogen pollution, another pressing environmental problem. That is the conclusion of a 10-year study by a researcher in the University of Minnesota Department of Forest Resources who studied the interaction of CO2 and nitrogen on 16 species of grasslands. Exhaust fumes and fertilizers produce nitrogen pollution, a primary cause of water degradation. One of the study’s key findings is that, though the combination of CO2 and nitrogen pollution does reduce species diversity, adding more CO2 to the mix reduces that change by half. The finding is important because scientists have feared that rising levels of CO2 could directly reduce plant diversity. The researcher emphasized that the finding does not detract from the need to curb CO2 emissions given the other environmental problems it causes. The study was published in the December 4 issue of Science.
Illustration by Cathie Bleck
The New Meaning of Computer Streaming
Researchers at the University of Minnesota department of civil engineering have developed VirtualStreamLab, a unique new computer model designed to help restore real rivers and streams back to health. It uses sophisticated numerical algorithms to simulate water flow with an unprecedented level of detail and realism. Recent data shows that 44 percent of the nation’s 3.5 million miles of rivers and streams are suffering from sedimentation, a major source of pollution, and the presence of excess nutrients. These conditions have serious consequences for entire watersheds, including poor flood control and harm to aquatic life. Historically, efforts to restore streams have been hampered by the inability to perceive their complex beds, banks, turbulence, and interactions with the environment.
VirtualStreamLab was unveiled at the 2009 American Physical Society Division of Fluid Dynamics meeting in Minneapolis.
Illustration by Daniel Baxter
Insights on Casual Sex
Researchers from the University of Minnesota School of Public Health have found that young adults who engage in casual sexual encounters do not appear to be at increased risk for harmful psychological outcomes as compared to sexually active young adults in committed relationships. While the study focused on the psychological impact, researchers cautioned that the physical risks of casual sex should not be overlooked.
The study assessed a diverse sample of 1,311 sexually active young adults. Eighty percent reported that their last sexual partner was an exclusive dating partner or a fiancé, spouse, or life partner. The remainder reported that their last sexual encounter was a close but not exclusive partner or a casual acquaintance. The study was published in the December issue of the journal Perspectives on Sexual and Reproductive Health.
Illustration by Lou Brooks
Predatory Middle Age
Wolves, long thought to be consummate predators their entire lives, actually begin to lose their edge in midlife, according to a study of wolves in Yellowstone National Park by a researcher in the University of Minnesota’s Department of Ecology, Evolution and Human Behavior. According to the study, Yellowstone Park wolves typically live to be about 6 years old and their ability to prey peaks when they are 2 to 3 years old. The finding is important because scientists are looking for answers to the decline in Yellowstone’s elk population. While some believe that wolves are responsible for the decline, the U study shows that the number of elk killed fluctuates based on the age structure of the wolf population at any given time: the higher the proportion of wolves over age 3, the lower the rate at which they kill elk. For every 10 percent rise in the proportion of wolves older than 3, the kill rate declined 10 percent to 15 percent.
The study was published in the December issue of the journal Ecology Letters.
Photography by Mark Payne-Gill/Minden Pictures
Understanding Puberty and Butterflies
metamorphosis, a University of Minnesota research team in the department of genetics, cell biology, and development has taken a big step toward understanding the onset of human puberty. The researchers studied PTTH, a hormone that triggers the mechanism of metamorphosis by acting like a key fitting into a lock. PTTH’s “key” identity has been known for 20 years, but it took the U team to find the “lock,” an enzyme that works like a master switch, turning on other enzymes that turn on still others and eventually lead to a rash of changes resulting in metamorphosis.
Because the onset of human puberty is brought about by a similar mechanism, the finding addresses the question of how a host of organisms, from a squirmy larva turning into a butterfly to a child becoming an adult, sense increasing body size and enter the next stage of development on schedule. The discovery might also lead to the development of environmentally friendly insecticides targeting a narrow range of species, such as mosquitoes. The research appears in the December 4 issue of Science. —Deane Morrison
Photograph by Ingo Arndt/Minden Pictures
A Leap Forward on PTSD
Researchers at the University of Minnesota Brain Sciences Center and Minneapolis Veterans Administration Medical Center have identified a biological marker in the brains of those exhibiting post-traumatic stress disorder (PTSD), a severe anxiety disorder that often affects war veterans and others who have suffered traumatic events. PTSD can manifest in flashbacks, recurring nightmares, rage, or hypervigilance. Complications can include alcohol and drug abuse, violent behavior, and suicide.
Researchers were able to differentiate PTSD patients from healthy control subjects using magnetoencephalography (MEG), a noninvasive measurement of magnetic fields in the brain. The measurements, unavailable with conventional brain scans such as X-ray, CT, or MRI, allowed researchers to locate the unique biomarkers in the brains of patients with PTSD.
The discovery is a major advance because currently there are no objective diagnostic tests for the disorder; diagnosis depends on the subjective judgment of the clinician. An objective test could give doctors a way to accurately diagnose the condition, assess its severity, and evaluate treatments. It could also guide those who decide who is entitled to disability payments and who is fit for redeployment.
Illustration by Jing Jing Tsong
Discoveries is edited by Cynthia Scott. University of Minnesota Alumni Association members may access many of the journals that published these studies through the Libraries Online member benefit. Go to www.MinnesotaAlumni.org/Libraries.