Posts tagged CU
Climate change: Big changes for big mammals
Jan 23rd
in mammal responses to climate change
If you were a shrew snuffling around a North American forest, you would be 27 times less likely to respond to climate change than if you were a moose grazing nearby.
That is just one of the findings of a new University of Colorado Boulder assessment led by Assistant Professor Christy McCain that looked at more than 1,000 different scientific studies on North American mammal responses to human-caused climate change. The CU-Boulder team eventually selected 140 scientific papers containing population responses from 73 North American mammal species for their analysis.
The studies assessed by the team examined seven different responses to climate change by individual mammal species: local extinctions of species known as extirpations, range contractions, range shifts, changes in abundance, seasonal responses, body size and genetic diversity. The researchers used statistical models to uncover whether the responses of the 73 mammals to a changing climate were related to aspects of their physiology and behavior or the location of the study population.
The analysis showed only 52 percent of the mammal species responded as expected to climate change, while 7 percent responded the opposite of expectations and the remaining 41 percent had no detectable response. The two main traits tied to climate change responses in the CU-Boulder study were large mammal body size and restricted times during a 24-hour day when particular mammal species are active, she said.
A paper on the study by McCain and former CU-Boulder postdoctoral fellow Sarah King was published online Jan. 22 in the journal Global Change Biology. The National Science Foundation funded the study. King is currently a research associate at Colorado State University.
While body size was by far the best predictor for response to climate change — almost all of the largest mammals responded negatively — the new study also showed that mammals active only during the day or only at night were twice as likely to respond to climate change as mammals that had flexible activity times, she said.
“This is the first time anyone has identified specific traits that tell us which mammals are responding to climate change and which are not,” said McCain of CU-Boulder’s ecology and evolutionary biology department.
McCain said she and King were surprised by some of the findings. “Overall the study suggests our large, charismatic fauna — animals like foxes, elk, reindeer and bighorn sheep — may be at more risk from climate change,” she said. “The thinking that all animals will respond similarly and uniformly to temperature change is clearly not the case.”
The researchers also found that species with higher latitudinal and elevation ranges, like polar bears, American pikas and shadow chipmunks, were more likely to respond to climate change than mammals living lower in latitude and elevation. The ability of mammals to hibernate, burrow and nest was not a good predictor of whether a species responded to climate change or not. American pikas have been extirpated from some of their previously occupied sites in the West, as have shadow chipmunks, which are in decline in California’s Yosemite National Park.
One of the most intriguing study findings was that some small mammals may shelter from climate change by using a wider array of “micro-climates” available in the vegetation and soil, she said. McCain compared the findings with the events at the K-T boundary 66 million years ago when an asteroid smacked Earth, drastically changing the climate and killing off the big dinosaurs but sparing many of the small mammals that found suitable shelter underground to protect them from the cataclysmic event.
“I think the most fascinating thing about our study is that there may be certain traits like body size and activity behaviors that allow some smaller mammals to expand the range of temperature and humidity available to them,” said McCain, also a curator of vertebrate zoology at the University of Colorado Museum of Natural History. “These areas and conditions are not available to bigger mammals that live above the vegetation and experience only ambient temperatures.”
The new study builds on a growing body of global information documenting the shifting behaviors and environments of organisms like flowers, butterflies and birds in response to a warming world, said McCain.
“If we can determine which mammals are responding to climate change and the ones that are at risk of disappearing, then we can tailor conservation efforts more toward those individual species,” said McCain. “Hopefully, this potential loss or decline of our national iconic mammals will spur more people to curb climate impacts by reducing overuse of fossil fuels.”
For more information on the ecology and evolutionary biology department visit http://ebio.colorado.edu. For more information on the University of Colorado Museum of Natural History visit http://cumuseum-archive.colorado.edu/About/directory.html.
Mining big data for performance clues as a study guide
Jan 21st
forgetting with personalized content review
Computer software similar to that used by online retailers to recommend products to a shopper can help students remember the content they’ve studied, according to a new study by the University of Colorado Boulder.
The software, created by computer scientists at CU-Boulder’s Institute for Cognitive Science, works by tapping a database of past student performance to suggest what material an individual student most needs to review.
For example, the software might know that a student who forgot one particular concept but remembered another three weeks after initially learning them is likely to need to review a third concept six weeks after it was taught. When a student who fits that profile uses the software, the computer can pull up the most useful review questions.
“If you have two students with similar study histories for specific material, and one student couldn’t recall the answer, it’s a reasonable predictor that the other student won’t be able to either, especially when you take into consideration the different abilities of the two students,” said CU-Boulder Professor Michael Mozer, senior author of the study published in the journal Psychological Science.
The process of combing “big data” for performance clues is similar to strategies used by e-commerce sites, Mozer said.
“They know what you browsed and didn’t buy and what you browsed and bought,” Mozer said. “They measure your similarity to other people and use purchases of similar people to predict what you might want to buy. If you substitute ‘buying’ with ‘recalling,’ it’s the same thing.”
The program is rooted in theories that psychologists have developed about the nature of forgetting. Researchers know that knowledge—whether of facts, concepts or skills—slips away without review, and that spacing the review out over time is crucial to obtaining robust and durable memories.
Still, it’s uncommon for students to do the kind of extended review that favors long-term retention. Students typically review material that was presented only in the most recent unit or chapter—often in preparation for a quiz—without reviewing previous units or chapters at the same time.
This leads to rapid forgetting, even for the most motivated learners, Mozer said. For example, a recent study found that medical students forget roughly 25 to 35 percent of basic science knowledge after one year and more than 50 percent by the next year.
Over the last decade, Mozer has worked with University of California, San Diego, psychologist Harold Pashler, also a co-author of the new study, to create a computer model that could predict how spaced review affects memory. The new computer program described in the study is an effort to make practical use of that model.
Robert Lindsey, a CU-Boulder doctoral student collaborating with Mozer, built the personalized review program and then tested it in a middle school Spanish class.
For the study, Lindsey and Mozer divided the material students were learning into three groups. For material in a “massed” group, the students were drilled only on the current chapter. For material in a “generic-spaced” group, the students were drilled on the most recent two chapters. For material in a “personalized-spaced” group, the algorithm determined what material from the entire semester each student would benefit most from reviewing.
In a cumulative test taken a month after the semester’s end, personalized-spaced review boosted remembering by 16.5 percent over massed study and by 10 percent over generic-spaced review.
In a follow-up experiment, Mozer and his colleagues compared their personalized review program to a program that randomly quizzes students on all units that have been covered so far. Preliminary results show that the personalized program also outperforms random reviews of all past material.
So far, the program has been tested only in foreign language classes, but Mozer believes the program could be helpful for improving retention in a wide range of disciplines, including math skills.
It’s not necessary to have a prior database of student behavior to implement the personalized review program. Students can begin by using the program as a traditional review tool that asks random questions, and as students answer, the computer begins to search for patterns in the answers. “It doesn’t take long to get lots and lots of data,” Mozer said.
The research was funded by the National Science Foundation and the McDonnell Foundation.
-CU-
Buffs demonic on defense, rebound from UCLA home loss
Jan 19th
BOULDER – Any lingering memories of the Colorado Buffaloes’ painful loss on Thursday night to UCLA – their first home defeat of the 2013-14 season – were quickly blocked out on Saturday.
Literally, forcefully, fervently.
Swatting away seven first-half shots and setting a pedal-to-the-metal pace that produced an early 20-2 lead, No. 21 CU slapped Southern California 83-62 at the Coors Events Center.
“This was just what the doctor ordered for this team . . . this was the kind of game we needed,” CU coach Tad Boyle said, noting the timing of the win couldn’t have been better after the 69-56 loss to UCLA and knee injuries last weekend that ended point guard Spencer Dinwiddie’s junior season and shelved freshman wing Tre’Shaun Fletcher for 6-8 weeks. Both players will undergo surgery.
Continued Boyle: “I’m really proud of our guys, from the end of the bench to the guys on the floor, for the way they responded. We talked about it at halftime; the frustrating thing about the UCLA game was second-chance points (20) and points off turnovers (20 off of 17 CU errors). We had four turnovers at halftime (12 total) and they had two offensive rebounds.
“Our team took what they had not done against UCLA and did a much better job. Obviously it’s one game, we have to move on. I said this after the UCLA game and I’ll say it again, ‘Don’t count this team out.’ These guys have toughness, they have grit, and we can win some games in this league. All you can ask for in life is an opportunity and we have a great one in front of us.”
That would be a Thursday night game at No. 1 Arizona, followed by a Saturday visit to Arizona State – a pair of desert spots where the Buffs went 0-2 last season to begin Pac-12 play. But needing a win Saturday to break a current two-game losing streak and maybe reestablish some of their swagger, the Buffs did both against the Trojans – obviously a right-place, right-time opponent.
Still, junior guard Askia Booker, one of four Buffs in double figures Saturday, kept the 21-point blowout in perspective. “We can’t get drunk off of this win,” he said. “USC is pretty low in the (Pac-12) standings and we’re about to go play the No. 1 team in the country. We have to stay locked in as a team.”
The Buffs (15-4 overall, 4-2 Pac-12) finished Saturday with a season-high 10 blocked shots – six shy of the school record – and held the Trojans (9-9, 0-5) to 36 percent shooting from the field while hitting 50.9 percent of their own shots.
CU outrebounded the visitors by 20 (43-23), with redshirt freshman Wesley Gordon collecting a game-high eight rebounds and accounting for five of the Buffs’ blocked shots. He also scored five points, made two assists, got one steal and hit two of his three shots from the field – including his first career 3-pointer.
“I loved the pace of the game,” said Boyle. “Our interior defense was good, blocking shots was good (and) getting off to a 20-2 lead was a confidence builder for our guys.”
Booker called the Buffs’ shot blocking “very important . . . blocked shots lead to transition baskets and that’s where we’re at our best. We’ve got big guys who run and finish.”
USC, said Booker, was noticeably frustrated with having its early shots contested and rejected: “Without a doubt . . . their No. 10 (Pe’Shon Howard) was looking around like, ‘I can’t get a layup up without it being knocked away.’ It’s really good when we’re all locked in and getting that kind of help from the weak side.”
That’s what Booker supplied on one of the more creative and crowd-pleasing first half blocks. Booker, pushing 6-2 in his sneakers, flew in and batted away a layup attempt by Trojans 7-footer D.J. Haley. It was only Booker’s second rejection of the season – and don’t bet on him forgetting it.
“I guess it was a pretty nice block and I’ll probably go watch that again,” Booker said. “It’s not that high; it’s just a good defensive play and we need stops like that whether it’s from me or Jaron (Hopkins) or Josh (Scott).”
CU also was nearly perfect from the free throw line, hitting 19 of 22 (86 percent) with Booker hitting all six of his attempts. He finished with 13 points on three-of-five shooting and had six of CU’s 15 assists.
“He has never had a game like this,” Boyle said. “He played within himself and was efficient. When he’s efficient we’re pretty darn good; I thought he was terrific.”
Booker was one of four Buffs in double figures, topped by Josh Scott’s 20. Xavier Johnson and Jaron Hopkins added 10 points each. J.T. Terrell and 7-2 center Omar Oraby led USC with 16 points apiece.
The Buffs led by as many 18 points in the first half and were up 17 (40-23) at intermission courtesy of a Booker buzzer beater. It came on a sweet step back shot by “Ski,” but it wasn’t indicative of the first-half storyline.
CU was demonic on defense with its shot-blocking spree and holding UCLA to two points for the game’s first 8:18. At the 11:48 mark, the Bruins were one of 12 from the field (8 percent) and the Buffs led 20-2, with the final five points of that bulge coming on two free throws by Booker after a technical foul on USC coach Andy Enfield and a 3-pointer by George King.
None of the Trojans escaped the Buffs’ first-half intensity – not even Enfield. The CU student section harassed him – good naturedly, of course – with a blown up mug shot of his wife, former model Amanda Marcum. But that probably wasn’t what incited the “T;” blame the Buffs for that. There was no discrepancy of personal fouls: USC was whistled for 16, CU for 15.