Recent work by grad student Denise Kendall and assistant professor Beth Schussler was selected as an Editors' Choice by Science.
Article abstract: Graduate teaching assistants (GTAs) are used extensively as instructors in higher education, yet their status and authority as teachers may be unclear to undergraduates, to administrators, and even to the GTAs themselves. This study explored undergraduate perception of classroom instruction by GTAs and professors to identify factors unique to each type of instructor versus the type of classes they teach. Data collection was via an online survey composed of subscales from two validated instruments, as well as one open-ended question asking students to compare the same class taught by a professor versus a GTA. Quantitative and qualitative results indicated that some student instructional perceptions are specific to instructor type, and not class type. For example, regardless of type of class, professors are perceived as being confident, in control, organized, experienced, knowledgeable, distant, formal, strict, hard, boring, and respected. Conversely, GTAs are perceived as uncertain, hesitant, nervous, relaxed, laid-back, engaging, interactive, relatable, understanding, and able to personalize teaching. Overall, undergraduates seem to perceive professors as having more knowledge and authority over the curriculum, but enjoy the instructional style of GTAs. The results of this study will be used to make recommendations for GTA professional development programs.
Showing posts with label Science. Show all posts
Showing posts with label Science. Show all posts
Friday, June 22, 2012
Friday, April 1, 2011
Science article on economic importance of bats
Bats in North America are under a two-pronged attack but they are not the only victim – so is the U.S. economy. Gary McCracken, head of the Department of Ecology and Evolutionary Biology at the University of Tennessee, Knoxville, along with lead author Justin Boyles of the University of Pretoria in South Africa, and coauthors Paul Cryan of the U.S. Geological Survey and Thomas Kunz of Boston University, analyzed the economic impact of the loss of bats in North America in agriculture and found it to be in the $3.7 to $53 billion a year range. This was published in the April 1 edition of Science.
Since 2006, more than a million bats have died due to a fungal disease called White-Nose Syndrome (WNS). At the same time, several migratory tree-dwelling species are being killed in unprecedented numbers by wind turbines. This hurts the economy because bats’ diet of pest insects reduces the damage the insects cause to crops and decreases the need for pesticides.
In fact, the researchers estimate the value of bats to the agricultural industry is roughly $22.9 billion a year, with the extremes ranging as low as $3.7 and $53 billion a year.
“These estimates include the reduced costs of pesticide applications that are not needed to suppress the insects consumed by bats. However, they do not include the downstream impacts of pesticides on humans, domestic and wild animals and our environment,” said McCracken. “Without bats, crop yields are affected. Pesticide applications go up. Even if our estimates were quartered, they clearly show how bats have enormous potential to influence the economics of agriculture and forestry.”
According to the researchers, a single colony of 150 big brown bats in Indiana eat nearly 1.3 million insects a year — insects that could potentially be damaging to crops.
WNS infects the skin of bats while they hibernate. Some species such as the little brown bat are likely to go extinct in parts of North America. The disease has quickly spread from Canada to Tennessee, Missouri and Oklahoma and actions to slow or stop it have proven unsuccessful.
It is unknown how many bats have died due to wind turbines, but the scientists estimate by 2020, wind turbines will have killed 33,000 to 111,000 annually in the Mid-Atlantic Highlands alone. Why migratory tree-dwelling species are drawn to the turbines remains a mystery.
Due to the economic and ecological importance, the researchers urge policy-makers to avoid a wait-and-see approach to the issue of widespread declines of bat populations.
“Not acting is not an option because the life histories of these flying, nocturnal mammals — characterized by long generation times and low reproductive rates — mean that population recovery is unlikely for decades or even centuries, if at all,” said McCracken.
According to McCracken, solutions will only be fueled in the next few years by increased awareness of the benefits of insectivorous bats among the public, policymakers and scientists.
Since 2006, more than a million bats have died due to a fungal disease called White-Nose Syndrome (WNS). At the same time, several migratory tree-dwelling species are being killed in unprecedented numbers by wind turbines. This hurts the economy because bats’ diet of pest insects reduces the damage the insects cause to crops and decreases the need for pesticides.
In fact, the researchers estimate the value of bats to the agricultural industry is roughly $22.9 billion a year, with the extremes ranging as low as $3.7 and $53 billion a year.
“These estimates include the reduced costs of pesticide applications that are not needed to suppress the insects consumed by bats. However, they do not include the downstream impacts of pesticides on humans, domestic and wild animals and our environment,” said McCracken. “Without bats, crop yields are affected. Pesticide applications go up. Even if our estimates were quartered, they clearly show how bats have enormous potential to influence the economics of agriculture and forestry.”
According to the researchers, a single colony of 150 big brown bats in Indiana eat nearly 1.3 million insects a year — insects that could potentially be damaging to crops.
WNS infects the skin of bats while they hibernate. Some species such as the little brown bat are likely to go extinct in parts of North America. The disease has quickly spread from Canada to Tennessee, Missouri and Oklahoma and actions to slow or stop it have proven unsuccessful.
It is unknown how many bats have died due to wind turbines, but the scientists estimate by 2020, wind turbines will have killed 33,000 to 111,000 annually in the Mid-Atlantic Highlands alone. Why migratory tree-dwelling species are drawn to the turbines remains a mystery.
Due to the economic and ecological importance, the researchers urge policy-makers to avoid a wait-and-see approach to the issue of widespread declines of bat populations.
“Not acting is not an option because the life histories of these flying, nocturnal mammals — characterized by long generation times and low reproductive rates — mean that population recovery is unlikely for decades or even centuries, if at all,” said McCracken.
According to McCracken, solutions will only be fueled in the next few years by increased awareness of the benefits of insectivorous bats among the public, policymakers and scientists.
Monday, November 29, 2010
Boyer Science paper
Alison Boyer, a new Research Assistant Professor in EEB, just published a paper in last week's issue of Science.
The Evolution of Maximum Body Size of Terrestrial Mammals
Felisa A. Smith, Alison G. Boyer, James H. Brown, Daniel P. Costa, Tamar Dayan,
S. K. Morgan Ernest, Alistair R. Evans, Mikael Fortelius, John L. Gittleman,
Marcus J. Hamilton, Larisa E. Harding, Kari Lintulaakso, S. Kathleen Lyons,
Christy McCain, Jordan G. Okie, Juha J. Saarinen, Richard M. Sibly, Patrick R. Stephens, Jessica Theodor, Mark D. Uhen
Science 330, 1216 (2010);
DOI: 10.1126/science.1194830
Abstract:
The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter remained approximately constant. There was remarkable congruence in the rate, trajectory, and upper limit across continents, orders, and trophic guilds, despite differences in geological and climatic history, turnover of lineages, and ecological variation. Our analysis suggests that although the primary driver for the evolution of giant mammals was diversification to fill ecological niches, environmental temperature and land area may have ultimately constrained the maximum size achieved.
The Evolution of Maximum Body Size of Terrestrial Mammals
Felisa A. Smith, Alison G. Boyer, James H. Brown, Daniel P. Costa, Tamar Dayan,
S. K. Morgan Ernest, Alistair R. Evans, Mikael Fortelius, John L. Gittleman,
Marcus J. Hamilton, Larisa E. Harding, Kari Lintulaakso, S. Kathleen Lyons,
Christy McCain, Jordan G. Okie, Juha J. Saarinen, Richard M. Sibly, Patrick R. Stephens, Jessica Theodor, Mark D. Uhen
Science 330, 1216 (2010);
DOI: 10.1126/science.1194830
Abstract:
The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter remained approximately constant. There was remarkable congruence in the rate, trajectory, and upper limit across continents, orders, and trophic guilds, despite differences in geological and climatic history, turnover of lineages, and ecological variation. Our analysis suggests that although the primary driver for the evolution of giant mammals was diversification to fill ecological niches, environmental temperature and land area may have ultimately constrained the maximum size achieved.
Subscribe to:
Posts (Atom)