Lake Tahoe’s clarity is currently not declining and its outlook is positive, suggests data from a collaborative effort of UC Davis researchers, the Tahoe Regional Planning Agency and the Tahoe Environmental Research Center.

“In terms of clarity, the outlook is hopeful,” said Dennis Oliver, public affairs director of the TRPA. “There’s been quite a lot of progress made to undo the damage that was seen here in the 1950s.“

Likewise, Geoff Schladow of the Tahoe Environmental Research Center, said, “Because of all the projects that are being done every year, we’re going to make more progress. I’m cautiously optimistic.“

Since 1968, UC Davis researchers have been measuring the clarity of Lake Tahoe. According to experts, the clarity of the lake is an overall indicator of the health of the waterway.

When measurements began, the visible average depth of clarity was 102.4 feet. Last year UC Davis reported that since 2001 the lake’s clarity hasn’t been declining as fast as it had in previous decades. Data from 2008 confirms this – last year’s average was 69.6, compared with 2007‘s average of 70.1 feet.

Researchers are able to accurately measure the clarity of Lake Tahoe’s water by using a 10-inch diameter “secchi” disk. Light penetrates the water and bounces off of the disk, allowing the observer to see it at a specific depth. At some depth, however, the fine particles and algae present in the water absorb the light, and the disk can no longer be seen.

The deeper the disk can be seen clearer the water; if the disk can only be seen at a shallow depth, the water is said to be less clear.

In addition to clarity measurements, a multitude of tests are currently performed on the lake’s water – including bacteria levels, temperature, oxygen levels and pH – giving experts an accurate indication of pollution and adverse changes to the lake and its wildlife.

Formerly, there was a 40-year-long decline in Lake Tahoe water clarity, and improvement projects were scarce. During the past 10 years, however, enough money was received from public and private sectors to fund environmental improvement projects, totaling $1 billion. Half of these funds were allocated specifically for water quality projects.

“Twenty-six acres of state highway were outfitted with water treatment, which provides advanced treatment of water before it gets to the lake,” Oliver said. “Also, we were able to remove about 60 miles of forest roads no longer needed … and the momentum still exists to continue these projects.“

This ambitious funding has not been spent in vain, for the decline in water clarity is starting to level off, and restoration movements are likely to continue.

As part of the restoration project, hundreds of millions of dollars are being spent to stop storm water and other pollutants, often runoff from golf courses, paved roads and private lawns, from entering Lake Tahoe and affecting its water quality in a negative manner, Schladow said.

Lake Tahoe has long been a place of recreation for UC Davis students, Northern Californians and Nevadans alike. But with such a large tourist population, pollution is inevitable.

“I think most of [the pollution] is human-caused. How can we continue to live here without having negative effects on Lake Tahoe? That is an important question,” Schladow said.

Oliver expressed similar concerns.

“We must balance [human populations] with environmental concerns, and the way to do that is with technology and sustainability,” Oliver said. “We’re also concerned about wildlife, air quality, scenic conditions and rural character.“

Experts are optimistic about Lake Tahoe’s future in part because a bill will be introduced before Congress this year backed by California and Nevada senators.

“We’re starting to see the lake is responding [to restoration projects] and the line is flattening. Over the next 10 years and $2.5 billion worth of work, we’re hoping that we’ll turn the corner,” Oliver said.

MICHAEL MILLER can be reached features@theaggie.org.

Insomnia may affect “hunger hormones“

UCLA researchers have uncovered that one of the two hormones that is primarily responsible for telling the body when it is hungry or when it is full is disrupted by chronic insomnia.

This is the first study looking into the elevated nocturnal levels of the two hormones – ghrelin and leptin – in patients diagnosed with primary insomnia. Ghrelin is a peptide secreted by the stomach that stimulates appetite. Secretion is increased before meals. Leptin, mainly secreted by the fat cells, affects a person’s weight by signaling the hypothalamus about the amount of the body’s fat storage. Decreased leptin indicates a fat shortage, promoting hunger; increasing levels promote the body to burn calories.

In the study, published in the May issue of Psychoneuroendocrinology, researchers measured the levels of the two hormones at various times during the night in healthy sleepers, and compared it with those with chronic insomnia.

The researchers discovered that while leptin levels were about the same between the two groups, ghrelin levels were 30 percent lower in those suffering from insomnia.

Although lower levels of ghrelin inhibit weight gain, lead researcher, Sarosh Motivala, compared the findings with other sleep deprivation studies and speculates that a switch may occur during the day. Typically, sleep loss leads to increased ghrelin levels and decreased leptin; such a combination stimulates appetite. Motivala is currently examining this switch in a new study.

Motivala said that the study showed a dysregulation in energy balance, which could explain why insomnia patients gain weight over time. He said he believes this find highlights the connections between diverse behavior such as eating and sleeping.

(Source: UC Newsroom)

FDA: Avoid pistachios

The Food and Drug Administration is recommending that consumption of pistachios should be avoided in light of another salmonella scare.

The FDA and the California Department of Health are looking into the possible contamination of pistachios processed by Setton Pistachio in Terra Bella, Calif. Setton is voluntarily recalling over 1 million pounds of the nuts, and has stopped distributing them for further sale.

The FDA says no illnesses have yet been reported from this case; the salmonella strains were found last week during a routine test by Kraft Foods, and unlike the peanut butter outbreak, the recall is a “proactive” measure. The FDA is currently setting up a website to aid and update consumers on the issue.

(Source: CNN.com)

U.S., Canada want increased regulation on ship emissions

Oceangoing ships coming into coastal regions of the United States and Canada may face stricter controls on emissions of sulfur, particulate matter such as soot and other pollutants that can harm human health.

The two countries have asked the International Maritime Organization, a United Nations agency that regulates international shipping, to designate a 200-mile buffer zone in which ships would have to make drastic cuts in their emissions. For example, ships would have to cut sulfur emissions by 98 percent by 2015, either by burning a cleaner fuel or by “scrubbing” exhaust gas to remove sulfur.

The agency expects that there are currently about 40 outgoing vessels docked in the American metropolitan areas that do not meet federal air quality standards.

Approval from the agency is expected next year; if approved, limits on emissions are could go into effect as early as 2012.

(Source: nytimes.com)

Online tool could predict risk of type II diabetes

British scientists have developed an online calculator for predicting the risk of developing adult-onset (type II) diabetes. After examining the medical records of people for over 15 years, excluding people already diagnosed with diabetes or those with incomplete records, researchers found nine significant risk factors for the condition.

Risk factors include age, ethnicity, body mass index, smoking, socioeconomic level, family history of diabetes, diagnosis of cardiovascular disease, hypertension and the use of steroid drugs.

The researchers then calculated the relative importance of such factors and incorporated them into an algorithm that could accurately predict the 10-year risk for type II diabetes.

The study was published online in BMJ on Mar. 17; an interactive version of the algorithm is available at qdscore.org. Although two features – ethnicity and postal code – are exclusive to Britain, lead researcher Dr. Julia Hippisley-Cox said not specifying those two factors will still give you fairly accurate results.

For those found to be high at risk, weight loss and exercise are essential for prevention, Hippisley-Cox said.

(Source: nytimes.com)

SCIENCE SCENE was compiled by ANNA OPALKA, who can be reached at features@theaggie.org.

Today

Opsin Expression in Fishes: Photoreceptor Plasticity and its Ecological Relevance

Inigo Novales Flamarique (Simon Fraser University, British Columbia)

1:10 to 2 p.m., 1022 Life Sciences

Sponsored by neurobiology, physiology and behavior, College of Biological Sciences

Topic to be announced (land, air and water resources)

Pasquale Steduto (Food and Agriculture Organization)

4:10 to 5:30 p.m., 3001 Plant and Environmental Sciences

Sponsored by land, air and water resources, Environmental Science and Policy

Thursday

Topic to Be Announced (Center for Neuroscience)

Karel Svoboda

4 to 5 p.m., Center for Neuroscience, 1544 Newton Court, Research Park

Sponsored by College of Biological Sciences, Center for Neuroscience

Mre11/Rad50 Complexes and DNA Double-strand Break Processing

Tanya Paull (University of Texas at Austin)

4:10 to 5 p.m., 1022 Life Sciences

Sponsored by College of Biological Sciences

Graduate Groups in Biochemistry & Molecular Biology and Cell & Developmental Biology, Section of Molecular & Cellular Biology, Departments of Biological Chemistry and Cell Biology & Human Anatomy, the Molecular & Cellular Biology Training Grant (NIH), and the Howard Hughes Medical Institute

Monday

The Effects of Vitamin A on Developing B Cells in the Chicken

Kim Livingston (UC Davis graduate student)

Noon to 1 p.m., Weir Room, 2154 Meyer

Sponsored by animal science

Barley Stripe Mosaic Virus and its Movement Processes

Andrew O. Jackson (UC Berkeley)

12:10 to 1 p.m., 115 Hutchison

Sponsored by plant pathology

Tuesday

The Metaphysics of Fundamentality

Ted Sider (New York University)

3:10 to 5:10 p.m., philosophy department library – 1231 Social Sciences and Humanities

Sponsored by philosophy

The coming revolutions in fundamental physics

Davis Gross, Nobel Laureate

8 to 10 p.m., AGR Hall, Buehler Alumni and Visitors Center

Sponsored by physics department

More seminars can be found at calendar.ucdavis.edu. If you’d like to publish a seminar here, contact us at features@theaggie.org.

Maybe the old adage “don‘t worry, be happy“ has some truth in it after all.

According to a study conducted by researchers at UC Davis and the University of Washington, although children between the ages of five and seven all understand the connection that negative emotions can cause poorer school performance, only the 7-year-olds realized the link between positive emotions and better school performance.

The study was published in the January/February issue of Child Development, the Society for Research in Child Development‘s journal.

Participants consisted of 5- to 7-year-olds and adults. The study had each participant listen to a story, which featured a different character and either a positive or negative event. The story ended with the character having to take a test later at school. The participants were then asked if the character would do worse, the same or better on the test than they usually did on that kind of test. To make it engaging for the children, the story had different types of tests, ranging from spelling and memory to science.

While all the participants understood the negative emotion link, not every 7-year-old and adult fully believed the positive emotion connection.

“Even the adults were not all consistently sure that feeling positive emotions would improve your performance,“ said Kristin Lagattuta, a UC Davis associate psychology professor and one of the authors for the study.

“Young kids understood … by age five that if you were feeling sad or angry, it would be very hard to do well on something like a cognitive test, and the adults fully agree on this,“ she said. “So if you [compare the results], even the adults think that negative emotions are far more debilitative on cognitive test performance than they think positive emotions are for enhancing.“

There are a few explanations for why people tend to discount the power of positive thinking. First of all, many people assume that a person‘s default mood is happy. Because of this, many might think that the performance would stay the same by thinking positively unless the person was extremely happy. However, some adults claim that this super happiness would be more distracting than helpful because they would think about what made them happy in the first place.

In addition to a person‘s default mood, many people believe that a positive physiological state, such as eating breakfast or getting a good night‘s sleep, would be more beneficial to the test taker than positive emotions, Lagattuta said.

The research shows clearly that children understand negative links at a much earlier age. This understanding of positive emotions comes later in development and even then, as the adults showed, does not necessarily mean it is internalized.

“It seems to be the case that negative emotions and negative events are very salient and attention-getting. In many ways, it makes sense that many children would understand them earlier than positive events,“ Lagattuta said.

The importance of the study comes from its practical applications. Teachers today tell their students the importance of the positive physiological states such as eating correctly and sleeping before a test. According to Lagattuta, because students have to take weeklong standardized tests, teachers should talk to their students about positive emotions.

“The more aware children are about how and why their feelings affect their school performance, the better prepared they will be to look out for situations where their emotions or physiological states could impact their performance,“ said Jennifer Amsterlaw, a research scientist at the University of Washington and principal author of the study. “[The students can] then take steps to improve the chances of a positive outcome.“

NICK MARKWITH can be reached at features@theaggie.org.