 | Faculty Research
9/20/2002Plant Diversity Repels Invaders
The latest in a series of experiments at the University’s Cedar Creek Natural History Area underscoring the importance of plant diversity finds that diverse ecosystems better hold off invading, non-native species. Ecology graduate student Thomas Kennedy and colleagues studied 147 plots planted with between one and 24 native species at Cedar Creek, north of the Twin Cities. After a period of weeding to allow the native plants to establish themselves, the researchers stopped removing any plants for two years. They then studied sections of the plots and found that plots with fewer native species had more and larger invaders. Kennedy theorizes that the more diverse the plant community, the more complete the use of resources and space, leaving fewer and less desirable toeholds for invading plants. Earlier results from Cedar Creek experimental plots found that diverse plant groups suffer less soil nutrient loss and withstand drought better than plant communities with few species, like lawns and tree farms. The new study was published in the June 6 edition of Nature.
Cerebellum’s Role Illuminated
In a finding that could refine rehabilitation efforts for some brain-injured patients, University researchers have determined how the cerebellum works in learning motor skills—physical movement abilities, such as walking, learned through practice. The cerebellum, located at the base of the brain, does not appear to have a role in learning new motor skills but does become active as tasks are refined. Researchers measured brain activity as subjects performed a reaction-time test, including pressing certain buttons when specific lights were flashed. At the same time they were asked to perform a second, distracting task, including counting the light flashes. The distraction prevented the subjects from consciously realizing that the lights were flashing in a specific sequence. When the distraction task was removed, subjects showed they had learned the sequence by their improved reaction times. The results were published in the June 14 edition of Science.
Stem Cell Studies Affirmed
University of Minnesota researchers formally published in June what they had long believed: Certain adult stem cells are able to become almost any cell in the human body. Dr. Catherine Verfaillie and her colleagues at the University’s Stem Cell Institute have said for more than two years that their "multipotent adult progenitor" cells appear able to grow themselves into various other cells, much the same as embryonic stem cells. Publication of the findings means that others in the field have reviewed the work and found that the experiments were valid. The findings also addressed the significant concern that inadvertent crossing of various cells may have led to the findings. In essence, the findings mean that these cells, found in the bone marrow of humans and other animals, may some day be able to be used to address cellular abnormalities, repair damaged organs, or grow new tissues. Researchers stress that many more experiments and trials are needed before any workable therapies could be created. Additionally, Verfaillie and others argue that experiments with embryonic stem cells should continue as well in order to determine which cells hold more promise for various conditions. The study was published in the June 20 issue of Nature.
The Power of Play
Recess is a vital part of academic achievement and social adjustment in elementary schools, University educational psychology professor Anthony Pellegrini and an English colleague write in the Spring 2002 issue of Early Report. Citing several other studies, they argue that recess and other breaks are vital to children staying attentive to standardized tasks. Recess also allows them to establish relationships and practice social skills. And successful participation in recess games helps children feel more competent in other school settings. In a study of English schools, however, lunch breaks had been reduced in 38 percent of schools over a five-year period and afternoon breaks had been eliminated altogether in 27 percent of elementary schools. The full article is available here.
|
Print View