Showing posts with label NATURE. Show all posts
Showing posts with label NATURE. Show all posts
Tuesday, September 2, 2014
Thursday, April 24, 2014
ECOLOGISTS LOOK AT RELATIONSHIP BETWEEN YELLOWSTONE'S WILLOWS AND STREAMS
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| Photo: Yellowstone Stream. From: Wikimedia. |
Earth Week: Whither Yellowstone's willows and the streams they shade?
Yellowstone's water table dropping below riverbank willow trees
Willows and streams. In Yellowstone, where there's one, the other isn't far behind.
On Earth Week, scientists are asking: How far do such connections reach?
New research on water-dependent willows shows that streams and willows may be conducting the music on Yellowstone's ecological dance floor.
Ecologists Tom Hobbs, Kristin Marshall and David Cooper published the results in a recent issue of the Journal of Ecology. Hobbs and Cooper are with Colorado State University (CSU) in Fort Collins, Marshall is at NOAA.
After wolves were extirpated from Yellowstone almost 100 years ago, elk multiplied, says Hobbs. The herbivores roamed across the landscape, nibbling willows to nubbins.
But the story doesn't end there.
With fewer willows to gnaw on, beavers began to decline. Crucially for willows, without the dams beavers build, which slow the flow of water, streams ran faster. Brooks soon became deeply carved into their banks from the force of rapidly-moving water.
Before long, the water table fell below the reach of streamside willows' roots.
Wolves and elk, beavers and willows: carefully choreographed parts
"All the possible interactions among plants and animals in nature are impossible to separately identify and measure," says Henry Gholz, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which funds the Yellowstone willow research through its Long Term Research in Environmental Biology (LTREB) Program.
"Yet scientists know these links are critical to the maintenance of functional ecosystems."
Over a 30-year-period, Hobbs and colleagues studied riparian willow (Salix spp.) establishment and stem growth. In Yellowstone's northern range, the scientists reconstructed willows' history from tree rings. The three-decade time-frame covered the reintroduction of wolves in 1995.
"What happens to willows is shaped more by how high the water table is," says Hobbs, "than by any other factor."
The finding shows how complicated ecosystem links can be, says Gholz. "The effects of elk browsing on streamside willows in Yellowstone over the past 30 years are related more to variations in year-to-year climate, age of the willow trees, and changes in streams due to declining numbers of beavers."
The scientists used climate variables such as annual precipitation, stream flow and growing season length; the abundance of herbivores (elk); and landscape elevation and an index of "topographic wetness" (how soggy the ground is) to predict willow growth before and after the reintroduction of wolves.
"Explaining variability in [willow] establishment required models with stream flow, annual precipitation and elk abundance," write the ecologists in their paper.
"The results show that changes in the growth of willows after the reintroduction of wolves," says Marshall, "can't be understood without considering all the variables."
Life as a willow: water required
Picture a willow as it leans over a river or stream. Willows, sallows and osiers form the genus Salix, made up of some 400 species of deciduous trees and shrubs. All are found on moist soils in cold and temperate regions of the Northern Hemisphere.
Most are known as willows, but some narrow-leaved shrub species are called osiers, and broader-leaved species are referred to as sallows, from an Old English word derived from the Latin term salix.
Willows are the dominant riparian, or riverside, woody vegetation in Yellowstone and across the Rocky Mountains, according to Hobbs.
In Yellowstone, willows are found along rivers and streams, as well as near springs, seeps and anywhere water is available.
"As long as willows' roots can reach groundwater," says Hobbs, "the trees can survive--and withstand very high levels of browsing by elk. It all comes down to water."
On Earth Week and every week, the dance of life needs all the partners
Restoring an ecologically complete ecosystem in Yellowstone requires the return of willows--and with them, beavers, says Hobbs.
Once willows have returned, beavers will gnaw down a certain number of the trees to build dams. The dams will slow stream flow, allowing yet more willows to grow.
Willows, streams and beavers; wolves and elk. Willows and streams may have the first dance. But without them all, Yellowstone's ecological music will eventually fade away.
-- Cheryl Dybas
Investigators
Fred Watson
David Cooper
Jennifer Hoeting
Matthew Kauffman
N. Thompson Hobbs
Related Institutions/Organizations
Colorado State University
Thursday, September 5, 2013
DIGITAL LEARNING
FROM: NATIONAL SCIENCE FOUNDATION
Nature field trips go digital
Harvard researchers tame the next learning frontier with mobile phones, environmental probes and virtual reality
The buzz around the pond these days isn't coming from bees. It's coming from middle-school students on a data collection field trip to a local pond. But on this trip they've traded paper and pencil for mobile phones and environmental probes. With their smartphones, students access interactive media such as video, audio, 3-D models and animations to learn about the ecosystem they're visiting as well as answer specific and open-ended questions about their data collection activities. Their probes measure environmental variables that contribute to water quality.
This augmented reality experience is part of a pilot program called EcoMOBILE developed by researchers at Harvard University's Graduate School of Education (HGSE). Funded by NSF and Qualcomm's Wireless Reach Initiative, EcoMOBILE has two goals. The first is to learn how technology impacts learning and the second is to help students connect abstract science concepts learned in the classroom with real-world experiences.
"Technology in and of itself does nothing for learning, but it can be a catalyst," says the project's principal investigator, Christopher Dede, Timothy E. Wirth Professor in Learning Technologies at Harvard. "We're interested in why technology impacts learning as much as whether it does or not. We are always concerned with how effective we can make these technologies and what the limits are."
Augmenting reality
The EcoMOBILE curriculum includes a pre-trip classroom session, one or more field trips and follow-up class sessions. During the initial session, students learn about water quality variables such as pH, dissolved oxygen and turbidity. They also practice using the smartphones and measurement probes they'll use at the pond. During the field trip, students use the mobile phones to navigate to "hotspots" where they collect water samples. The phone software prompts students to make observations about the pond and its organisms; provides information about concepts such as dissolved oxygen; supplies step-by-step instructions for obtaining and testing a water sample; and delivers feedback on the just-completed measurement.
Back in the classroom, students share the observations they made at the pond. They compile their data, creating graphs and calculating the range and mean of each set of measurements. They then discuss their findings and explore why variations may have occurred.
During the EcoMOBILE experience, students proceed at their own pace, personalizing their experience. "This approach engages them to a different degree than other formats," says project co-director Amy Kamarainen, a limnologist (a scientist who studies inland waters). "Students take ownership of the data and experience a new level of responsibility for their work." She adds that the EcoMOBILE experience is like a mini-apprenticeship, allowing students to see science as a creative process. "It helps students enjoy what they're doing but also understand that ecology is a very analytic field."
The technology also helps students study the complex time and spatial scales characteristic of ecosystems. "Ecosystems can be hard to learn about because kids have a limited amount of time to study them," says Kamarainen.
While at the pond, students learn about change over decades by accessing a video that simulates a visitor from 1850 discussing the pond's history. Another activity allows students to view 3-D molecular simulations of ecosystem processes such as photosynthesis.
Simulating reality
EcoMOBILE complements EcoMUVE, a multi-user virtual environment for classrooms created five years ago by Dede and co-principal investigator Tina Grotzer, an associate professor of education at HGSE. "ECOMUVE is like a flight simulator. We can create experiences not found in nature," says Dede. "EcoMOBILE is like flying the plane. You can get very good in the simulator, but ultimately you want to get people to be effective in the real world."
In EcoMUVE students assume a specific role: Water chemist, naturalist, microscopic specialist or private investigator and for eight virtual days are responsible for monitoring and collecting data in their respective areas. Students work in teams to analyze the data and create a concept map that illustrates the cause and effect relationships found in the ecosystem.
Assessing reasoning patterns
EcoMUVE and EcoMOBILE offer an opportunity to assess how students approach situations requiring complex reasoning. "We can look at where kids go in EcoMUVE and what kinds of data they collect. We see that patterns of movement shift," explains Grotzer.
When students first enter the virtual pond their movements are random. After a fish kill, the initial movement patterns give way to more purposeful ones. The changes suggest that students' thinking has changed and they are attending to different features and data sources in the environment says Grotzer, who as director of the NSF-funded "Understandings of Consequence Project" for more than a decade has studied how students reason about complex causal patterns.
Refining the technology for the future
After several years of iterative design, EcoMUVE is available as a free download through a licensing arrangement with Harvard. EcoMOBILE, however, is still under development and available only for research purposes. Although the program, built on the FreshAiR platform, runs on both Android and iPhones, some of the 3-D simulations are only available using Androids.
"We want to be able to make EcoMOBILE customizable," says Shari Metcalf, project co-director. With time, the team anticipates creating a website that would include software templates teachers can download to tailor augmented reality scenarios to their own local ecosystems.
Seventh-grade teacher Allison Kugler has worked with the EcoMOBILE project for three semesters and thinks the technology is a good fit for middle school students. "They want to be challenged but not get frustrated," she says. In a comparison of EcoMUVE and traditional hands-on activities, Kugler found that students had an easier time understanding ecosystem concepts with EcoMUVE.
As applications software becomes more refined and mobile phones more sophisticated, Dede suggests student-directed learning tools like EcoMOBILE will become commonplace. "We can't just keep loading more topics into classroom learning. We need to focus on 24/7 learning," he says. "This is the next frontier."
Nature field trips go digital
Harvard researchers tame the next learning frontier with mobile phones, environmental probes and virtual reality
The buzz around the pond these days isn't coming from bees. It's coming from middle-school students on a data collection field trip to a local pond. But on this trip they've traded paper and pencil for mobile phones and environmental probes. With their smartphones, students access interactive media such as video, audio, 3-D models and animations to learn about the ecosystem they're visiting as well as answer specific and open-ended questions about their data collection activities. Their probes measure environmental variables that contribute to water quality.
This augmented reality experience is part of a pilot program called EcoMOBILE developed by researchers at Harvard University's Graduate School of Education (HGSE). Funded by NSF and Qualcomm's Wireless Reach Initiative, EcoMOBILE has two goals. The first is to learn how technology impacts learning and the second is to help students connect abstract science concepts learned in the classroom with real-world experiences.
"Technology in and of itself does nothing for learning, but it can be a catalyst," says the project's principal investigator, Christopher Dede, Timothy E. Wirth Professor in Learning Technologies at Harvard. "We're interested in why technology impacts learning as much as whether it does or not. We are always concerned with how effective we can make these technologies and what the limits are."
Augmenting reality
The EcoMOBILE curriculum includes a pre-trip classroom session, one or more field trips and follow-up class sessions. During the initial session, students learn about water quality variables such as pH, dissolved oxygen and turbidity. They also practice using the smartphones and measurement probes they'll use at the pond. During the field trip, students use the mobile phones to navigate to "hotspots" where they collect water samples. The phone software prompts students to make observations about the pond and its organisms; provides information about concepts such as dissolved oxygen; supplies step-by-step instructions for obtaining and testing a water sample; and delivers feedback on the just-completed measurement.
Back in the classroom, students share the observations they made at the pond. They compile their data, creating graphs and calculating the range and mean of each set of measurements. They then discuss their findings and explore why variations may have occurred.
During the EcoMOBILE experience, students proceed at their own pace, personalizing their experience. "This approach engages them to a different degree than other formats," says project co-director Amy Kamarainen, a limnologist (a scientist who studies inland waters). "Students take ownership of the data and experience a new level of responsibility for their work." She adds that the EcoMOBILE experience is like a mini-apprenticeship, allowing students to see science as a creative process. "It helps students enjoy what they're doing but also understand that ecology is a very analytic field."
The technology also helps students study the complex time and spatial scales characteristic of ecosystems. "Ecosystems can be hard to learn about because kids have a limited amount of time to study them," says Kamarainen.
While at the pond, students learn about change over decades by accessing a video that simulates a visitor from 1850 discussing the pond's history. Another activity allows students to view 3-D molecular simulations of ecosystem processes such as photosynthesis.
Simulating reality
EcoMOBILE complements EcoMUVE, a multi-user virtual environment for classrooms created five years ago by Dede and co-principal investigator Tina Grotzer, an associate professor of education at HGSE. "ECOMUVE is like a flight simulator. We can create experiences not found in nature," says Dede. "EcoMOBILE is like flying the plane. You can get very good in the simulator, but ultimately you want to get people to be effective in the real world."
In EcoMUVE students assume a specific role: Water chemist, naturalist, microscopic specialist or private investigator and for eight virtual days are responsible for monitoring and collecting data in their respective areas. Students work in teams to analyze the data and create a concept map that illustrates the cause and effect relationships found in the ecosystem.
Assessing reasoning patterns
EcoMUVE and EcoMOBILE offer an opportunity to assess how students approach situations requiring complex reasoning. "We can look at where kids go in EcoMUVE and what kinds of data they collect. We see that patterns of movement shift," explains Grotzer.
When students first enter the virtual pond their movements are random. After a fish kill, the initial movement patterns give way to more purposeful ones. The changes suggest that students' thinking has changed and they are attending to different features and data sources in the environment says Grotzer, who as director of the NSF-funded "Understandings of Consequence Project" for more than a decade has studied how students reason about complex causal patterns.
Refining the technology for the future
After several years of iterative design, EcoMUVE is available as a free download through a licensing arrangement with Harvard. EcoMOBILE, however, is still under development and available only for research purposes. Although the program, built on the FreshAiR platform, runs on both Android and iPhones, some of the 3-D simulations are only available using Androids.
"We want to be able to make EcoMOBILE customizable," says Shari Metcalf, project co-director. With time, the team anticipates creating a website that would include software templates teachers can download to tailor augmented reality scenarios to their own local ecosystems.
Seventh-grade teacher Allison Kugler has worked with the EcoMOBILE project for three semesters and thinks the technology is a good fit for middle school students. "They want to be challenged but not get frustrated," she says. In a comparison of EcoMUVE and traditional hands-on activities, Kugler found that students had an easier time understanding ecosystem concepts with EcoMUVE.
As applications software becomes more refined and mobile phones more sophisticated, Dede suggests student-directed learning tools like EcoMOBILE will become commonplace. "We can't just keep loading more topics into classroom learning. We need to focus on 24/7 learning," he says. "This is the next frontier."
Friday, August 23, 2013
NATURE AND INNOVATIVE MATERIALS
FROM: NATIONAL SCIENCE FOUNDATION
Inspired by nature: textured materials to aid industry and military
Innovation Corps team developed metals and plastic that repel water, capture sunlight and prevent ice build-up
The lotus leaf has a unique microscopic texture and wax-like coating that enables it to easily repel water. Taking his inspiration from nature, a University of Virginia professor has figured out a way to make metals and plastics that can do virtually the same thing.
Mool Gupta, Langley Distinguished Professor in the university's department of electrical and computer engineering, and director of the National Science Foundation's (NSF) Industry/University Cooperative Research Center for Lasers and Plasmas, has developed a method using high-powered lasers and nanotechnology to create a similar texture that repels water, captures sunlight and prevents the buildup of ice.
These textured materials can be used over large areas and potentially could have important applications in products where ice poses a danger, for example, in aviation, the automobile industry, the military, in protecting communication towers, blades that generate wind energy, bridges, roofs, ships, satellite dishes, and even snowboards.
In commercial and military aviation, for example, these materials could improve airline safety by making current de-icing procedures, which include scraping and applying chemicals, such as glycol, to the wings, unnecessary.
For residents in the frigid northeast, many of whom rely on satellite systems, "it could mean they won't lose their signal, and they won't have to go outside with a hammer and chisel and break off the ice," Gupta says.
The materials' ability to trap sunlight also could enhance the performance of solar cells.
Gupta and his research team first made a piece of textured metal that serves as a mold to mass-produce many pieces of plastic with the same micro-texture. The replication process is similar to the one used in manufacturing compact discs. The difference, of course, is that the CD master mold contains specific information, like a voice, whereas, "in our case we are not writing any information, we are creating a micro-texture," Gupta says.
"You create one piece of metal that has the texture," Gupta adds. "For multiple pieces of plastic with the texture, you use the one master made of metal to stamp out multiple pieces. Thus, whatever features are in your master are replicated in the special plastic. Once we create that texture, if you put a drop of water on the texture, the water rolls down and doesn't stick to it, just like a lotus leaf. We have created a human-made structure that repels water, just like the lotus leaf."
The process of making the metal with the special texture works like this: the scientists take high-powered lasers, with energy beams 20 million times higher than that of a laser pointer, for example, and focus the beams on a metal surface. The metal absorbs the laser light and heats to a melting temperature of about 1200 degrees Centigrade, or higher, a process that rearranges the surface material to form a microtexture.
"All of this happens in less than 0.1 millionth of a second," Gupta says. "The microtexture is self-organized. By scanning the focused laser beam, we achieve a large area of microtexture. The produced microtexture is used as a stamper to replicate microtexture in polymers. The stamper can be used many, many times, allowing a low cost manufacturing process. The generated microtextured polymer surface shows very high water repellency."
In the fall of 2011, Gupta was among the first group of scientists to receive a $50,000 NSF Innovation Corps (I-Corps) award, which supports a set of activities and programs that prepare scientists and engineers to extend their focus beyond the laboratory into the commercial world.
Such results may be translated through I-Corps into technologies with near-term benefits for the economy and society. It is a public-private partnership program that teaches grantees to identify valuable product opportunities that can emerge from academic research, and offers entrepreneurship training to faculty and student participants.
The other project members are Paul Caffrey, a doctoral candidate under Gupta's supervision, and Martin Skelly of Charleston, S.C., a veteran of banking in the former Soviet Union who serves as business mentor and is involved in new business investments.
The team participated in a three-day entrepreneurship workshop at Stanford University run by entrepreneurs from Silicon Valley. "We are still pursuing the commercial potential," Gupta says. "The idea is to look at what market can use this technology, how big the market is, and how long it will take to get into it."
-- Marlene Cimons, National Science Foundation
Inspired by nature: textured materials to aid industry and military
Innovation Corps team developed metals and plastic that repel water, capture sunlight and prevent ice build-up
The lotus leaf has a unique microscopic texture and wax-like coating that enables it to easily repel water. Taking his inspiration from nature, a University of Virginia professor has figured out a way to make metals and plastics that can do virtually the same thing.
Mool Gupta, Langley Distinguished Professor in the university's department of electrical and computer engineering, and director of the National Science Foundation's (NSF) Industry/University Cooperative Research Center for Lasers and Plasmas, has developed a method using high-powered lasers and nanotechnology to create a similar texture that repels water, captures sunlight and prevents the buildup of ice.
These textured materials can be used over large areas and potentially could have important applications in products where ice poses a danger, for example, in aviation, the automobile industry, the military, in protecting communication towers, blades that generate wind energy, bridges, roofs, ships, satellite dishes, and even snowboards.
In commercial and military aviation, for example, these materials could improve airline safety by making current de-icing procedures, which include scraping and applying chemicals, such as glycol, to the wings, unnecessary.
For residents in the frigid northeast, many of whom rely on satellite systems, "it could mean they won't lose their signal, and they won't have to go outside with a hammer and chisel and break off the ice," Gupta says.
The materials' ability to trap sunlight also could enhance the performance of solar cells.
Gupta and his research team first made a piece of textured metal that serves as a mold to mass-produce many pieces of plastic with the same micro-texture. The replication process is similar to the one used in manufacturing compact discs. The difference, of course, is that the CD master mold contains specific information, like a voice, whereas, "in our case we are not writing any information, we are creating a micro-texture," Gupta says.
"You create one piece of metal that has the texture," Gupta adds. "For multiple pieces of plastic with the texture, you use the one master made of metal to stamp out multiple pieces. Thus, whatever features are in your master are replicated in the special plastic. Once we create that texture, if you put a drop of water on the texture, the water rolls down and doesn't stick to it, just like a lotus leaf. We have created a human-made structure that repels water, just like the lotus leaf."
The process of making the metal with the special texture works like this: the scientists take high-powered lasers, with energy beams 20 million times higher than that of a laser pointer, for example, and focus the beams on a metal surface. The metal absorbs the laser light and heats to a melting temperature of about 1200 degrees Centigrade, or higher, a process that rearranges the surface material to form a microtexture.
"All of this happens in less than 0.1 millionth of a second," Gupta says. "The microtexture is self-organized. By scanning the focused laser beam, we achieve a large area of microtexture. The produced microtexture is used as a stamper to replicate microtexture in polymers. The stamper can be used many, many times, allowing a low cost manufacturing process. The generated microtextured polymer surface shows very high water repellency."
In the fall of 2011, Gupta was among the first group of scientists to receive a $50,000 NSF Innovation Corps (I-Corps) award, which supports a set of activities and programs that prepare scientists and engineers to extend their focus beyond the laboratory into the commercial world.
Such results may be translated through I-Corps into technologies with near-term benefits for the economy and society. It is a public-private partnership program that teaches grantees to identify valuable product opportunities that can emerge from academic research, and offers entrepreneurship training to faculty and student participants.
The other project members are Paul Caffrey, a doctoral candidate under Gupta's supervision, and Martin Skelly of Charleston, S.C., a veteran of banking in the former Soviet Union who serves as business mentor and is involved in new business investments.
The team participated in a three-day entrepreneurship workshop at Stanford University run by entrepreneurs from Silicon Valley. "We are still pursuing the commercial potential," Gupta says. "The idea is to look at what market can use this technology, how big the market is, and how long it will take to get into it."
-- Marlene Cimons, National Science Foundation
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