OREGON STATE UNIVERSITY

scientific research and advances

Scientists outline long-term sea-level rise in response to warming of planet

CORVALLIS, Ore. – A new study estimates that global sea levels will rise about 2.3 meters, or more than seven feet, over the next several thousand years for every degree (Celsius) the planet warms.

This international study is one of the first to combine analyses of four major contributors to potential sea level rise into a collective estimate, and compare it with evidence of past sea-level responses to global temperature changes.

Results of the study, funded primarily by the National Science Foundation and the German Federal Ministry of Education and Research, are being published this week in the Proceedings of the National Academy of Sciences.

“The study did not seek to estimate how much the planet will warm, or how rapidly sea levels will rise,” noted Peter Clark, an Oregon State University paleoclimatologist and author on the PNAS article. “Instead, we were trying to pin down the ‘sea-level commitment’ of global warming on a multi-millennial time scale. In other words, how much would sea levels rise over long periods of time for each degree the planet warms and holds that warmth?”

“The simulations of future scenarios we ran from physical models were fairly consistent with evidence of sea-level rise from the past,” Clark added. “Some 120,000 years ago, for example, it was 1-2 degrees warmer than it is now and sea levels were about five to nine meters higher. This is consistent with what our models say may happen in the future.”

Scientists say the four major contributors to sea-level rise on a global scale will come from melting of glaciers, melting of the Greenland ice sheet, melting of the Antarctic ice sheet, and expansion of the ocean itself as it warms. Several past studies have examined each of these components, the authors say, but this is one of the first efforts at merging different analyses into a single projection.

The researchers ran hundreds of simulations through their models to calculate how the four areas would respond to warming, Clark said, and the response was mostly linear. The amount of melting and subsequent sea-level response was commensurate with the amount of warming. The exception, he said, was in Greenland, which seems to have a threshold at which the response can be amplified.

“As the ice sheet in Greenland melts over thousands of years and becomes lower, the temperature will increase because of the elevation loss,” Clark said. “For every 1,000 meters of elevation loss, it warms about six degrees (Celsius). That elevation loss would accelerate the melting of the Greenland ice sheet.”

In contrast, the Antarctic ice sheet is so cold that elevation loss won’t affect it the same way. The melting of the ice sheet there comes primarily from the calving of icebergs, which float away and melt in warmer ocean waters, or the contact between the edges of the ice sheet and seawater.

In their paper, the authors note that sea-level rise in the past century has been dominated by the expansion of the ocean and melting of glaciers. The biggest contributions in the future may come from melting of the Greenland ice sheet, which could disappear entirely, and the Antarctic ice sheet, which will likely reach some kind of equilibrium with atmospheric temperatures and shrink significantly, but not disappear.

“Keep in mind that the sea level rise projected by these models of 2.3 meters per degree of warming is over thousands of years,” emphasized Clark, who is a professor in Oregon State University’s College of Earth, Ocean, and Atmospheric Sciences. “If it warms a degree in the next two years, sea levels won’t necessarily rise immediately. The Earth has to warm and hold that increased temperature over time.

“However, carbon dioxide has a very long time scale and the amounts we’ve emitted into the atmosphere will stay up there for thousands of years,” he added. “Even if we were to reduce emissions, the sea-level commitment of global warming will be significant.”

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Peter Clark, cell phone: 541-740-5237 (clarkp@geo.oregonstate.edu)

Lionfish expedition: down deep is where the big, scary ones live

CORVALLIS, Ore. – Last month, the first expedition to use a deep-diving submersible to study the Atlantic Ocean lionfish invasion found something very disturbing – at 300 feet deep, there were still significant populations of these predatory fish, and they were big.

Big fish in many species can reproduce much more efficiently than their younger, smaller counterparts, and lionfish are known to travel considerable distances and move to various depths. This raises significant new concerns in the effort to control this invasive species that is devastating native fish populations on the Atlantic Coast and in the Caribbean Sea.

“We expected some populations of lionfish at that depth, but their numbers and size were a surprise,” said Stephanie Green, the David H. Smith Conservation Research Fellow in the College of Science at Oregon State University, who participated in the dives. OSU has been one of the early leaders in the study of the lionfish invasion.

“This was kind of an ‘Ah hah!’ moment,” she said. “It was immediately clear that this is a new frontier in the lionfish crisis, and that something is going to have to be done about it. Seeing it up-close really brought home the nature of the problem.”

OSU participated in this expedition with researchers from a number of other universities, in work supported by Nova Southeastern University, the Guy Harvey Foundation, NOAA, and other agencies. The five-person  submersible “Antipodes” was provided by OceanGate, Inc., and it dove about 300 feet deep off the coast of Ft. Lauderdale, Fla., near the “Bill Boyd” cargo ship that was intentionally sunk there in 1986 to create an artificial reef for marine life.

That ship has, in fact, attracted a great deal of marine life, and now, a great number of lionfish. And for that species, they are growing to an unusually large size – as much as 16 inches.

Lionfish are a predatory fish that’s native to the Pacific Ocean and were accidentally introduced to Atlantic Ocean waters in the early 1990s, and there became a voracious predator with no natural controls on its population. An OSU study in 2008 showed that lionfish in the Atlantic have been known to reduce native fish populations by up to 80 percent.

Eradication appears impossible, and they threaten everything from coral reef ecosystems to local economies that are based on fishing and tourism.

Whatever is keeping them in check in the Pacific – and researchers around the world are trying to find out what that is – is missing here. In the Caribbean, they are found at different depths, in various terrain, are largely ignored by other local predators and parasites, and are rapidly eating their way through entire ecosystems. They will attack many other species and appear to eat constantly.

And, unfortunately, the big fish just discovered at greater depths pose that much more of a predatory threat, not to mention appetite.

“A lionfish will eat almost any fish smaller than it is,” Green said. “Regarding the large fish we observed in the submersible dives, a real concern is that they could migrate to shallower depths as well and eat many of the fish there. And the control measures we’re using at shallower depths – catch them and let people eat them – are not as practical at great depth.”

Size does more than just increase predation.  In many fish species, a large, mature adult can produce far more offspring that small, younger fish. A large, mature female in some species can produce up to 10 times as many offspring as a fish that’s able to reproduce, but half the size.

Trapping is a possibility for removing fish at greater depth, Green said, and could be especially effective if a method were developed to selectively trap lionfish and not other species. Work on control technologies and cost effectiveness of various approaches will continue at OSU, she said.

When attacking another fish, a lionfish uses its large, fan-like fins to herd smaller fish into a corner and then swallow them in a rapid strike. Because of their natural defense mechanisms they are afraid of almost no other marine life, and will consume dozens of species of the tropical fish and invertebrates that typically congregate in coral reefs and other areas. The venom released by their sharp spines can cause extremely painful stings to humans.

Aside from the rapid and immediate mortality of marine life, the loss of herbivorous fish will also set the stage for seaweed to potentially overwhelm the coral reefs and disrupt the delicate ecological balance in which they exist.

This newest threat follows on the heels of overfishing, sediment deposition, nitrate pollution in some areas, coral bleaching caused by global warming, and increasing ocean acidity caused by carbon emissions. Lionfish may be the final straw that breaks the back of Western Atlantic and Caribbean coral reefs, some researchers believe.

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Stephanie Green, 541-737-5364

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Submersible research

Submersible in Florida


Exploring sunken ship

Lionfish near sunken ship


Lionfish

Lionfish

Fear of deportation not an issue for farmworkers who get care from community health centers

CORVALLIS, Ore. – Migrant workers are more likely to receive medical care from community health centers in partnership with faith-based organizations, a new study shows, because fear of deportation is lower than they might face at other medical facilities.

The study was recently published online in the Journal of Immigrant and Minority Health.

Daniel López-Cevallos, associate director of research at Oregon State University’s Center for Latino/a Studies and Engagement, said this research points to the importance of health services being administered to migrant farmworkers by trusted institutions.

López-Cevallos, who is lead author of this study, is an expert on migrant farmworker health and has worked in public health projects with rural, indigenous, and low-income communities in Ecuador, and with Latino immigrants in Oregon.

“It has been assumed in most of the literature that fear of deportation is associated with use of health services, across the board,” he said. “There is a strong belief by many workers that they don’t want to touch the system because it might hurt their chances of someday becoming documented or jeopardize their children’s well-being.”

However, that fear wasn’t a factor with Oregon migrant workers in this study. The researchers interviewed 179 Mexican-origin indigenous and mestizo farmworkers who attended a community health center in the northern Willamette Valley. While the majority of workers – 87 percent – said they were afraid of deportation, this fear was not tied to their use of medical or dental care.

“So this fear of deportation exists, but in this particular community, it was not associated with use of medical services,” López-Cevallos said.

The researchers found two important factors influencing use of medical services – these workers were being served by a trusted community health organization that has served the area for decades, and those who attended a local church were more likely to use dental care.

“Some churches provide support to migrant farmworkers, which may include connecting them with needed dental care,” he said. “So we see that when services are offered by trusted institutions, such as a community health center or a faith-based organization, it can make all the difference.”

Despite the relative confidence migrant workers expressed about community health centers and churches, only 37 percent of the farmworkers surveyed had used medical care in the previous year, a number similar to national statistics on migrant workers. López-Cevallos believes many workers fear losing their jobs if they take time to see a doctor, and most don’t have health insurance.

Because of these barriers and others, it’s even more important to make sure safe, adequate health care is available to workers, he said, especially at times and locations that work best with fieldwork schedules.

“Migrant and seasonal farmworkers are an integral part of our food system, creating over $3 billion in economic activity annually, just in Oregon,” López-Cevallos said. “We get the benefit of their labor through our inexpensive food. It is in our best interest as a society to make sure that they, and their children, are healthy and cared for.”

Junghee Lee and William Donlan with Portland State University co-authored this study, which was funded by a grant from the Oregon Community Foundation.

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Daniel López-Cevallos, 541-737-3850

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Harvesting potatoes
Historic photo of Mexican braceros harvesting potatoes on an Oregon farm in the 1940s. Photo courtesy of OSU Special Collections

The sounds of science – melting of iceberg creates surprising ocean din

CORVALLIS, Ore. – There is growing concern about how much noise humans generate in marine environments through shipping, oil exploration and other developments, but a new study has found that naturally occurring phenomena could potentially affect some ocean dwellers.

Nowhere is this concern greater than in the polar regions, where the effects of global warming often first manifest themselves. The breakup of ice sheets and the calving and grounding of icebergs can create enormous sound energy, scientists say. Now a new study has found that the mere drifting of an iceberg from near Antarctica to warmer ocean waters produces startling levels of noise.

Results of the study are being published this month in Oceanography.

A team led by Oregon State University researchers used an array of hydrophones to track the sound produced by an iceberg through its life cycle, from its origin in the Weddell Sea to its eventual demise in the open ocean. The goal of the project was to measure baseline levels of this kind of naturally occurring sound in the ocean, so it can be compared to anthropogenic noises.

“During one hour-long period, we documented that the sound energy released by the iceberg disintegrating was equivalent to the sound that would be created by a few hundred supertankers over the same period,” said Robert Dziak, a marine geologist at OSU’s Hatfield Marine Science Center in Newport, Ore., and lead author on the study.

“This wasn’t from the iceberg scraping the bottom,” he added. “It was from its rapid disintegration as the berg melted and broke apart. We call the sounds ‘icequakes’ because the process and ensuing sounds are much like those produced by earthquakes.”

Dziak is a scientist with the Cooperative Institute for Marine Resources Studies (CIMRS), a collaborative program between Oregon State University and NOAA based at OSU’s Hatfield center. He also is on the faculty of OSU’s College of Earth, Ocean, and Atmospheric Sciences.

When scientists first followed the iceberg, it encountered a 124-meter deep shoal, causing it to rotate and grind across the seafloor. It then began generating semi-continuous harmonic tremors for the next six days. The iceberg then entered Bransfield Strait and became fixed over a 265-meter deep shoal, where it began to pinwheel. The harmonic tremors became shorter and less pronounced.

It wasn’t until the iceberg broke loose and drifted into the warmer waters of the Scotia Sea that the real action began. Photos from the International Space Station showed visible melt ponds on the iceberg’s surface, indicating it had was in a period of rapid disintegration. Within two months, the iceberg had broken apart and scientists were no longer able to track it via satellite.

But the scientists’ hydrophone array recorded the acoustic signature of the breakup – short duration, broadband signals that were distinctly different from the harmonic tremors, and much louder.

“You wouldn’t think that a drifting iceberg would create such a large amount of sound energy without colliding into something or scraping the seafloor,” noted Dziak, who has monitored ocean sounds using hydrophones for nearly two decades.  “But think of what happens why you pour a warm drink into a glass filled with ice. The ice shatters and the cracking sounds can be really dramatic. Now extrapolate that to a giant iceberg and you can begin to understand the magnitude of the sound energy.”

“In fact, the sounds produced by ice breakup near Antarctica are often clearly recorded on hydrophones that we have near the equator,” Dziak added.

Scientists are just starting to study the impact of anthropogenic and naturally occurring sounds on marine life and are unsure about the possible impacts. Most at-risk are those animals that use sound to facilitate their life-sustaining activities, such as feeding, breeding and navigation.

“The breakup of ice and the melting of icebergs are natural events, so obviously animals have adapted to this noise over time,” Dziak said. “If the atmosphere continues to warm and the breakup of ice is magnified, this might increase the noise budget in the polar areas.

“We don’t know what impact this may have,” Dziak added, “but we are trying to establish what natural sound levels are in various parts of the world’s oceans to better understand the amount of anthropogenic noise that is being generated.”

The research is supported primarily by the NOAA Ocean Exploration and Research Program, the Department of Energy, and the Korea Polar Research Institute.

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Bob Dziak, 541-867-0175; robert.dziak@oregonstate.edu

Antifreeze, cheap materials may lead to low-cost solar energy

The study this story is based on is available in ScholarsArchive@OSU; http://bit.ly/10Zj0SK

 

CORVALLIS, Ore. – A process combining some comparatively cheap materials and the same antifreeze that keeps an automobile radiator from freezing in cold weather may be the key to making solar cells that cost less and avoid toxic compounds, while further expanding the use of solar energy.

And when perfected, this approach might also cook up the solar cells in a microwave oven similar to the one in most kitchens.

Engineers at Oregon State University have determined that ethylene glycol, commonly used in antifreeze products, can be a low-cost solvent that functions well in a “continuous flow” reactor – an approach to making thin-film solar cells that is easily scaled up for mass production at industrial levels.

The research, just published in Material Letters, a professional journal, also concluded this approach will work with CZTS, or copper zinc tin sulfide, a compound of significant interest for solar cells due to its excellent optical properties and the fact these materials are cheap and environmentally benign.

“The global use of solar energy may be held back if the materials we use to produce solar cells are too expensive or require the use of toxic chemicals in production,” said Greg Herman, an associate professor in the OSU School of Chemical, Biological and Environmental Engineering. “We need technologies that use abundant, inexpensive materials, preferably ones that can be mined in the U.S. This process offers that.”

By contrast, many solar cells today are made with CIGS, or copper indium gallium diselenide. Indium is comparatively rare and costly, and mostly produced in China. Last year, the prices of indium and gallium used in CIGS solar cells were about 275 times higher than the zinc used in CZTS cells.

The technology being developed at OSU uses ethylene glycol in meso-fluidic reactors that can offer precise control of temperature, reaction time, and mass transport to yield better crystalline quality and high uniformity of the nanoparticles that comprise the solar cell – all factors which improve quality control and performance.

This approach is also faster – many companies still use “batch mode” synthesis to produce CIGS nanoparticles, a process that can ultimately take up to a full day, compared to about half an hour with a continuous flow reactor. The additional speed of such reactors will further reduce final costs.

“For large-scale industrial production, all of these factors – cost of materials, speed, quality control – can translate into money,” Herman said. “The approach we’re using should provide high-quality solar cells at a lower cost.”

The performance of CZTS cells right now is lower than that of CIGS, researchers say, but with further research on the use of dopants and additional optimization it should be possible to create solar cell efficiency that is comparable.

This project is one result of work through the Center for Sustainable Materials Chemistry, a collaborative effort of OSU and five other academic institutions, supported by the National Science Foundation. Funding was provided by Sharp Laboratories of America. The goal is to develop materials and products that are safe, affordable and avoid the use of toxic chemicals or expensive compounds.

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Greg Herman, 541-737-2496

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Solar cell nanoparticles

Solar nanoparticles

OSU study suggests reducing air-polluting PAHs may lower levels of lung cancer deaths

CORVALLIS, Ore. – High emissions of polycyclic aromatic hydrocarbons (PAHs) can be linked to lung cancer deaths in the United States and countries with a similarly high socioeconomic rank, including Canada, Australia, France, and Germany, according to a study by Oregon State University.

Researchers reviewed a range of information from 136 countries, including average body mass index, gross domestic product per capita, the price of cigarettes, smoking rates, and the amount of PAHs emitted into the air. PAHs are a group of more than 100 chemicals, some of which are carcinogenic when inhaled or ingested. They most commonly come from vehicle exhaust and burning coal and wood.

OSU researchers calculated how measures of health, wealth and pollution related to lung cancer deaths in each country.

"Analyzing data on a global scale revealed relationships between PAH emissions and smoking rates on the lung cancer death rates in each country," said Staci Simonich, a co-author of the study and toxicologist at OSU. "Ultimately, the strength of the relationships was determined by the country’s socioeconomic status."

While the link between smoking and lung cancer is well-established, OSU researchers did not find a correlation between cigarette smoking rates and lung cancer death rates in countries with high levels of income. Researchers attribute this conclusion to previous studies showing high-income smokers tend to light up less often.

OSU's study also suggests that reducing smoking rates could significantly lessen lung cancer deaths in countries with a lower socioeconomic status, including North Korea, Nepal, Mongolia, Cambodia, Bangladesh and many others. Researchers found that lung cancer mortality rates in these countries negatively correlated with price – meaning cheaper cigarettes are often associated with higher levels of deaths from lung cancer.

Detectable lung cancer can take 20 years to develop, and the poorest countries in the study had an average age of death of 54. OSU researchers suggest heavy smokers in these countries can sometimes die before tumors attributable to lung cancer become apparent.

"If the life expectancies were the same in all of the countries we reviewed, it's possible we would see a consistent relationship between PAH emissions and lung cancer," said Simonich, an OSU professor of environmental and molecular toxicology.

The study, "Association of Carcinogenic Polycyclic Aromatic Hydrocarbon Emissions and Smoking with Lung Cancer Mortality Rates on a Global Scale," was recently published in the journal Environmental Science and Toxicology.

The Pacific Northwest National Laboratories in Richland, Wash. assisted with calculating the statistical associations between data used in the study. The National Institutes of Environmental Health Sciences funded the research through OSU’s Superfund Research Program.

Cancer is the second-leading cause of death worldwide. Lung cancer accounts for 12 percent of all cancer diagnoses and is the leading cancer killer of men and second among women, according to the American Cancer Society.

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Staci Simonich, 541-737-9194

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Staci Simonich, OSU environmental chemist

Staci Simonich, an OSU environmental chemist, calculated how measures of health, wealth and pollution related to lung cancer deaths around the world. (Photo by Lynn Ketchum.)

More Americans want government to stay out of international affairs

CORVALLIS, Ore. – The number of Americans wanting their government to stay out of international affairs is higher than it has been since the Vietnam War, according to a new analysis.

In an article published this week in Orbis: A Journal of World Affairs, Oregon State University historian Christopher McKnight Nichols notes that doubts about American involvement abroad are on the rise, up 10 percent in a decade. He connects current reluctance on the part of many Americans to get involved militarily and politically with foreign nations to a long-standing tradition in U.S. politics.

“Virtually all isolationists in the history of the United States have subscribed to some form of international engagement, whether that is economic, cultural, political or intellectual,” he said. “There is no such thing as a complete isolationist. What we do have is a rich history of Americans who have taken on isolationist or anti-interventionist beliefs at different times, and helped transform or influence the political system and policy.”

Nichols, an assistant professor in the School of History, Philosophy, and Religion at OSU, is an expert on isolationism, internationalism, and the history of U.S. roles in the world and military interventions abroad.

In his article, he links the “heyday” of American isolationism of the 1920s and 1930s to current events, including polls showing nearly 70 percent of Americans reject further U.S. efforts to intervene or to promote democracy abroad.

Nichols also wants to take back the term “isolationist” from its common stereotype of a conservative mindset that wants to wall off from the outside world. Famous figures, ranging from peace activist Jane Addams and racial reformer W.E.B. Du Bois to writer Mark Twain and former U.S. Sen. William Borah, a nationalist who opposed the League of Nations, have all favored anti-war and anti-imperialistic isolationist policies.

“They say politics makes strange bedfellows, and we can certainly trace this with the isolationist movement, which tended to attract people on both the far left and far right,” Nichols said. “Today we see that same sort of tendency with some young anti-war activists supporting someone like Ron Paul.”

Most of these type of isolationist sentiments can be traced to three “policy pillars” – expressed by George Washington, Thomas Jefferson, and James Monroe – in laying out the relationship between domestic and foreign commitments, types of diplomatic and military isolation, and debates over foreign policy cautiousness that have had a deep impact on U.S. foreign relations for more than a century.

“These are the touchstones for all foreign policy debate, then and since,” he said. “The key precepts were: no permanent alliances or binding foreign entanglements, peace and honest friendship with all nations, enhancing and protecting international commerce, heralding unilateral action, and asserting U.S. rights to hemispheric defense and a wide sphere of primary U.S. influence abroad.”

Nichols said that isolationism as a strain of thought that informs how American citizens and policymakers evaluate options abroad and sometimes sways policy cannot be overstated. Eight years ago there were far more troops on the ground overseas than today, and he said President Obama has shown a reluctance to put “boots on the ground” in places like Libya and Syria, causing some of his critics to call him a “neo-isolationist.”

“With President Obama, we are back to small-scale, multilateral interventions, more like those that we had in the Clinton era,” Nichols said. “During Clinton’s presidency, the U.S. deployed forces abroad approximately 80 times in foreign humanitarian and peacekeeping operations, but these were mostly conflicts with small troop footprints, or Special Forces, characterized by few American causalities.

“In the wake of the Iraq War, in light of the drawdown in Afghanistan, and given pressing economic and political concerns at home, the U.S. public is increasingly reluctant to sacrifice American lives or to materially support intervention and aid abroad.”

Nichols is the author of “Promise and Peril: America at the Dawn of a Global Age,” which traces the origins of isolationism back to the debates over U.S. imperialism at the end of the 19th century and its continuities over the next-half century.

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Children with delayed motor skills struggle more socially

CORVALLIS, Ore. – Studies have shown that children with autism often struggle socially and now new research suggests that a corresponding lack of motor skills – including catching and throwing – may further contribute to that social awkwardness.

The findings, published in the July issue of Adapted Physical Activity Quarterly, add to the growing body of research highlighting the link between autism and motor skill deficits.

Lead author Megan MacDonald is an assistant professor in the College of Public Health and Human Sciences at Oregon State University. She is an expert on the movement skills of children with autism spectrum disorder.

In the study, researchers looked at a group of young people ages 6 to 15 diagnosed with autism spectrum disorder. All 35 of the students were considered high-functioning and attended typical classrooms. The researchers looked at two types of motor skills – “object-control” motor skills, which involve more precise action such as catching or throwing – and “locomotion” skills, such as running or walking. Students who struggled with object-control motor skills were more likely to have more severe social and communication skills than those who tested higher on the motor skills test.

“So much of the focus on autism has been on developing social skills, and that is very crucial,” MacDonald said. “Yet we also know there is a link between motor skills and autism, and how deficits in these physical skills play into this larger picture is not clearly understood.”

Developing motor skills can be crucial for children because students often “mask” their inability to participate in basic physical activities. A student with autism may not be participating on the playground because of a lack of social skills, but the child may also be unsure of his or her physical ability to play in these activities.

“Something which seems as simple as learning to ride a bike can be crucial for a child with autism,” MacDonald said. “Being able to ride a bike means more independence and autonomy. They can ride to the corner store or ride to a friend’s house. Those kind of small victories are huge.”

She said the ability to run, jump, throw and catch isn’t just for athletic kids – physical activity is linked not only to health, but to social skills and mental well-being.

“I often show people photos of what I like to do in my spare time – canoeing, hiking, snowshoeing, and then point out that these require relatively proficient motor skills,” she said. “But that is not why I do those things. I’m doing it because I’m with my friends and having fun.”

MacDonald said the positive news for parents and educators is that motor skills can be taught.

“We have programs and interventions that we know work, and have measurable impact on motor skill development,” MacDonald said. “We need to make sure we identify the issue and get a child help as early as possible.”

This study was coauthored by Catherine Lord of Weill Cornell Medical College and Dale Ulrich of the University of Michigan.

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Megan MacDonald, 541-737-3273

Climate change threatens forest survival on drier, low-elevation sites

CORVALLIS, Ore. – Predicted increases in temperature and drought in the coming century may make it more difficult for conifers such as ponderosa pine to regenerate after major forest fires on dry, low-elevation sites, in some cases leading to conversion of forests to grass or shrub lands, a report suggests.

Researchers from Oregon State University concluded that moisture stress is a key limitation for conifer regeneration following stand-replacing wildfire, which will likely increase with climate change. This will make post-fire recovery on dry sites slow and uncertain. If forests are desired in these locations, more aggressive attempts at reforestation may be needed, they said.

The study, published in Forest Ecology and Management, was done in a portion of the Metolius River watershed in the eastern Cascade Range of Oregon, which prior to a 2002 fire was mostly ponderosa pine with some Douglas-fir and other tree species. The research area was not salvage-logged or replanted following the severe, stand-replacing fire.

“A decade after this fire, there was almost no tree regeneration at lower, drier sites,” said Erich Dodson, a researcher with the OSU Department of Forest Ecosystems and Society. “There was some regeneration at higher sites with more moisture. But at the low elevations, it will be a long time before a forest comes back, if it ever does.”

Similar situations may be found in many areas of the American West in coming decades, the researchers say, and recruitment of new forests may be delayed or prevented – even in climate conditions that might have been able to maintain an existing forest. While mature trees can use their roots to tap water deeper in the soil, competition with dense understory vegetation can make it difficult for seedlings to survive.

Openings in ponderosa pine forests created by wildfire have persisted for more than a century on harsh, south-facing slopes in Colorado, the researchers noted in their report. And fire severity is already increasing in many forests due to climate change – what is now thought of as a drought in some locations may be considered average by the end of the next century.

If trees do fail to regenerate, it could further reduce ecosystem carbon storage and amplify the greenhouse effect, the study said.

Restoration treatment including thinning and prescribed burning may help reduce fire severity and increase tree survival after wildfire, as well as provide a seed source for future trees, Dodson said. These dry sites with less resilience to stand-replacing fire should be priorities for treatment, if maintaining a forest is a management objective, the study concluded.

Higher-elevation, mixed conifer forests in less moisture-limited sites may be able to recover from stand-replacing wildfire without treatment, the researchers said.

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Erich Dodson, 541-908-0227

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Slow recovery

Slow forest recovery

New dispatch system could save money for trucking industry, make life easier for drivers

The study this story is based on is available online: http://hdl.handle.net/1957/38433

 

CORVALLIS, Ore. – Engineers at Oregon State University are studying a new approach to organize and route truck transportation that could save millions of dollars, improve the quality of life for thousands of truck drivers and make freight transportation far more efficient.

The findings, published recently in Transportation Research Part E, show the feasibility of the new system. More research is still needed before implementation, but there’s potential to revolutionize the way that truck transportation is handled in the United States and around the world, some experts say.

Loads could be delivered more rapidly, costs could be lowered, and the exhausting experience of some truck drivers who often spend two to three weeks on the road between visits back home might be greatly reduced. This difficult lifestyle often leads them to quit their job as a result.

That turnover problem is sufficiently severe that more long-haul, full-truckload drivers quit every year than there are trucks of that type on the road.

“The perceived quality of life for long-haul truck drivers is poor, and it shouldn’t have to be that way,” said Hector Vergara, an assistant professor in the OSU School of Mechanical, Industrial and Manufacturing Engineering, who is working on this project in collaboration with researchers at the University of Arkansas.

“It will take a transition for companies to see how the approach we are studying can work effectively, but it should help address several of the problems they face,” he said.

In truck transportation, some of the existing approaches include “point to point,” in which one driver stays with a full load all the way to its often-distant destination; “hub and spoke” systems in which less-than-full loads are changed at selected points; and “relay” networks in which the drivers change but the load stays on the truck.

None of these systems by themselves are ideal for long-haul transport. The hub and spoke system is among the most popular with drivers because they get home much more frequently, but it can be costly and inefficient for full-truckload transportation. Relay networks make sense in theory but are difficult to implement.

The new approach under study combines the relay system and the point-to-point system for full-truckload transport. The researchers at OSU developed a new mathematical approach to optimize the design of the dispatching system for the movement of goods and to minimize the impact on drivers. It’s one of the first models of its type to create a mixed-fleet dispatching system at a large scale.

“We now know this approach can work,” Vergara said. “Compared to point-to-point, this system should cut the length of trips a driver makes by about two-thirds, and get drivers back to their homes much more often. We can also keep loads moving while drivers rest, and because of that save significant amounts of money on the number of trucks needed to move a given amount of freight.”

The computer optimization determines the best way to dispatch loads and tells where to locate relay points, and how different loads should be routed through the relay network.

Truck transportation systems will never be perfect, researchers concede, because there are so many variables that can cause unpredictable problems – weather delays, road closures, traffic jams, truck breakdowns, driver illnesses. But the current system, especially for long-haul, point-to-point transport, is already riddled with problems, and significant improvements based on computer optimization should be possible.

Disillusionment with existing approaches led to a shortage of 125,000 truck drivers in 2011, the researchers noted in the study. The negative economic impacts of this system also reach beyond just the trucking industry, they said.

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Hector Vergara, 541-737-0955