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UMaine Today Magazine


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Zebrafish
 

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Arsenic in zebras

In one of the first reports of its kind, microbiologists at the University of Maine have shown that arsenic exposure, at levels deemed safe in drinking water, suppresses the overall innate immune health in zebrafish.

Zebrafish are used as model organisms for studying immunotoxicity of environmental toxicants.

The researchers studied the effects of low concentrations of arsenic on zebrafish resistance to infection. They found that exposure to two concentrations of arsenic, both of which are considered safe in drinking water, resulted in zebrafish embryos being more than 50 times more susceptible to viral and 17 times more prone to bacterial infections.

Exposure to 2 ppb and 10 ppb (parts per billion) arsenic resulted in slight increases in total arsenic content in the zebrafish. The increases were enough to bring about dramatic declines in essential innate immune functions. Exposure to arsenic inhibited the ability of the fish to clear both viral and bacterial infection from their systems.

Arsenic is a naturally occurring element in soil, air and water that is generally considered nontoxic. However, it can accumulate in the environment at toxic levels due to pollution and human activities such as mining.

The researchers graduate student Akshata Nayak, postdoctoral researcher Christopher Lage and associate professor Carol Kim published their findings in the journal Toxicological Sciences.


Hunting lynx

Canada lynx prefer to hunt in the Maine woods where their favorite food snowshoe hare is relatively accessible, but not necessarily the most abundant, according to newly published research by University of Maine wildlife ecologists Angela Fuller and Daniel Harrison, and Maine Department of Inland Fisheries and Wildlife biologist Jennifer Vashon.

The researchers found that three female and three male lynx snow tracked for more than 40 miles during two winters preferred woods with 1126 years of postharvest growth regenerating clear-cut forests with tall regrowth (nearly 24 feet tall) and established, partially harvested stands.

Not as much to their liking were regenerating clear-cuts with tree height less than 14 feet, stands partially harvested in less than a decade, and mature second-growth forests.

Even though some stands have higher densities of snowshoe hares, lynx selected tracts that provided intermediate cover for hares. Lynx are visual foragers that hunt by stalking or ambushing.

In the contiguous United States, Maine has the only population of Canada lynx east of Minnesota. The study, published in the Journal of Wildlife Management, sheds light on how the wild cats, designated as federally threatened, use human-altered habitats in the southeastern portion of their range. Data on their winter habitat selection and foraging success in relation to silvicultural treatments is vital to lynx conservation.


Location, Location, Location

Businesses are attracted to locations with high quarterly and six-month employment stability, according to a study of Maine companies that began operation in 19992000. This suggests that business owners favor places with a strong year-round economy over areas with seasonal spikes in economic activity, according to University of Maine economist Todd Gabe.

Gabe studied nearly 1,600 businesses that began operations in 317 Maine municipalities. His analysis, which accounted for other location factors such as taxes, population size and industry clusters, found that annual fluctuations in local economic activity and employment do not appear to deter new business activity. But in municipalities with seasonal employment spikes, there are far fewer businesses opening their doors.

These findings are particularly pertinent in Maine, where strong seasonal swings are of concern in some parts of the state in the summer and fall.

Writing in the journal Land Economics, Gabe noted that policymakers need to take into account the effects of instability when evaluating economic development strategies.


Follow the Teacher

When it comes to leaders in our school systems, most people think only of administrators. But it takes many people to really mobilize a school for student learning, according to University of Maine education researcher Gordon Donaldson.

The most important among them are teachers.

"At issue is our understanding of leadership itself," says Donaldson, writing in the journal Educational Leadership. "Most of us hold the deep-seated assumption that leaders must have appointments and titles that formalize
their leadership and officially confirm their knowledge, traits and competencies."

Such a narrow definition underestimates the role of teacher leaders and the difference they can make in education, Donaldson says. Teacher leaders are individuals and groups of educators whose professional relationships and commitments in a school foster instructional innovation. As leaders, they help build relationships among their peers, maintain a sense of purpose and improve instructional practice. Teacher leaders' assets complement principal leadership.

"Whereas principals can shape teachers' beliefs, attitudes and behaviors, other teachers do shape them," says Donaldson. "Teacher leaders understand this and are deliberate about shaping their environment in a positive, responsible way. They draw on their relationships and their strong sense of purpose to help colleagues explore, share and improve the practices they use daily with students."


Birds in the postharvest woods

In the longest experimental investigation to date of the effects of a group-selection timber harvest on forest birds, University of Maine researchers found that nine of the 22 species abundant enough for individual analysis in a Maine woods study area responded positively in the postharvest period.

In particular, the Eastern Wood-Pewee, Winter Wren, Pine Warbler and White-throated Sparrow increased in abundance in the managed half of the area following timber harvest, which involved removal of small groups of mixed-aged trees at short intervals.

Eight other bird species were apparently unaffected. Of the five species that suggested a negative effect, only one, the Veery, a medium-size thrush, showed a strong negative response to the timber harvest that occurred on half of UMaine's 100-acre Holt Research Forest.

The first-cutting cycle of a group-selection timber harvest creates patches of habitat similar to the small openings caused by natural disturbance. These patches provide habitat for species that inhabit early-successional forest growth, yet have little effect on the abundance of mature closed-canopy bird species.

The 20-year study by UMaine wildlife ecologists Steven Campbell, Jack Witham and Malcolm Hunter, published in the journal Conservation Biology, provides important information on the strength, direction and duration of temporal changes in bird populations following forest management.

The study is particularly pertinent as managers of woodlands turn to group-selection harvesting as an alternative to clear-cutting. In addition, the number of small privately owned forests in the United States of comparable size to the Holt Research Forest is rising.


South Asian monsoons

An ice core from Mt. Everest shows evidence that the South Asian monsoon, the largest seasonal reversal of wind patterns and precipitation on Earth, has weakened in the past 1,000 years in the northerly, high-elevation regions of monsoon influence, according to climate change researchers at the University of Maine and the Joint Key Laboratory of Cryosphere and Environment in China.

However, low-elevation records from south of the Himalayas demonstrate that the monsoon has strengthened in the past few centuries.

The researchers, who reported their findings in Geophysical Research Letters, noted that the ice core revealed a decrease in marine and increase in continental air masses related to relatively high summer surface pressure over Mongolia, resulting in a reduction in northward incursions of the summer South Asian monsoon since around 1400 AD.

The north-south regional differences in the Asian monsoon reflect a southward shift in its mean summer position, say the researchers, led by Susan Kaspari, a Ph.D. candidate in UMaine's Climate Change Institute. The change in monsoon circulation at 1400 AD coincides with a reduction in solar output and the onset of the Little Ice Age.


By the Numbers: New minerals discovered

On a geological expedition along the windswept slopes of the Larsemann Hills in Antarctica, samples of the area's unique rock formations collected by University of Maine geologist Edward Grew revealed three minerals stornesite-(Y), chopinite and tassieite previously unknown to science.

The unique mineralogy of the Larsemann Hills, located on the eastern shore of Prydz Bay in Princess Elizabeth Land, inspired Grew and his colleague Chris Carson of Geoscience Australia to make the three-month expedition in 200304.

In UMaine's Department of Earth Sciences, Grew and Martin Yates identified the minerals using photomicrographs and a powerful electron microprobe. After determining each sample's optical, chemical and crystallographic properties, in collaboration with mineralogists in Germany and Switzerland, Grew submitted the data to a special commission of the International Mineralogical Association, which formally approved the three new minerals.

When new minerals are identified, some have little significance while others end up being tremendously important, says Grew, who has discovered 10 in his career. "Ultimately, discoveries like these contribute to our understanding of the origin of rocks, plate tectonics and other processes, and give us valuable insights into temperature, pressure and other conditions at different points in the Earth's history," he says.

This past October, Grew and UMaine Climate Change Institute Director Paul Mayewski were among 471 scientists named American Association for the Advancement of Science Fellows. Grew was recognized for "distinguished research on the role of lithium, beryllium, and boron in metamorphism at high temperatures and pressures, with emphasis on the Precambrian of Antarctica." Mayewski was cited for "seminal contributions to our understanding of climate change through ice and snow studies."


Arts and sciences

Nineteenth-century oceanographer and navigator Prince Albert I of Monaco once called art and science "the two directive forces of civilization."

Indeed, oceans are replete with literary, artistic and musical allusion and vice versa, according to University of Maine marine scientist Malcolm Shick. That's why, for the past three years, his introductory course on the biology of marine organisms has incorporated an arts and humanities component in an effort to "put marine biology into its wider aesthetic and historical context."

In an essay written for the Chamber Music Society of the Maine Center for the Arts, Shick details his extensive approach to "an aesthetic marine biology" in the classroom. He uses works of marine biologists who were also artists, and pieces by artists whose works were based on their direct, sympathetic experience with ocean life.

They include naturalist Philip Henry Gosse, whose illustrated books about marine life on the Devonshire Coast helped drive the Victorian craze for seaside natural history, and marine ecologist T.A. Stephenson; artists Andrew Wyeth, Henri Matisse and Jackson Pollock; musicians and composers such as J.S. Bach; and writers from Shakespeare to Steinbeck.

Last February at the American Society of Limnology and Oceanography's national conference in Santa Fe, N.M., Shick coproduced "Plankton as
an Artistic Inspiration," an art exhibit, lecture and documentary exploring the influence of the microscopic shapes and forms in art and design. The exhibition captured the attention of the principal international science weeklies, Nature and Science.


Special screenings

University of Maine audiologist Amy Booth has spent her career providing hearing services to underserved populations in this country and around the globe. In October, she was in China as a member of an international team of health professionals providing audiology screenings and hearing aid assessments to one such group Special Olympics athletes.

Booth was invited to the Special Olympics World Summer Games in Shanghai, Oct. 210, to provide training and to help implement the Healthy Hearing segment of the Special Olympics Healthy Athletes initiative.

With more than 7,000 athletes competing in the Special Olympics World Summer Games, Booth and her colleagues did nearly 450 hearing screenings and hearing aid assessments daily. In a day and a half, the team dispensed 120 hearing aids donated by various hearing aid manufacturers.

Booth has been invited to participate with Healthy Hearing in the World Winter Games in Idaho in 2009 and the World Summer Games in Greece in 2011.

UMaine Today Magazine
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