DELTA SKELTER 

As floodwaters surge through the upper Mississippi Delta this week — likely cresting in Greenville, Miss., today, and in Vicksburg Thursday — forecasters say river levels will continue rising for days across much of the region. Parts of eastern Arkansas, western Mississippi and northeastern Louisiana remain at high risk from flooding, as does the Atchafalaya River Basin in south-central Louisiana, which is being intentionally flooded to divert water from major cities along the Mississippi, namely Baton Rouge and New Orleans. The rising Atchafalaya River was already lapping at a downtown riverwalk in Morgan City, La., on Monday, CNN reports, and may bury towns like Butte La Rose and Krotz Springs under 15 feet of water.

The Atchafalaya diversion is possible because of the Morganza Spillway, which the U.S. Army Corps of Engineers began opening Saturday for the first time since 1973. As of Monday night, 15 of the spillway's 125 gates had been opened, diverting about 763,000 gallons of water per second from the Mississippi into the Atchafalaya. The Corps may eventually open a quarter of the gates, but Louisiana Gov. Bobby Jindal said Monday the spillway is already doing its job — although he cautioned residents not to let down their guard. "The crests have been lowered modestly in a number of places in Louisiana, but there is still a significant amount of water coming our way," Jindal said at a news conference in Baton Rouge. "Even with the lower projections, we know this water will impact households and families and that is why the National Guard and local officials are working around the clock to keep our people safe."

Plus, as AccuWeather points out, the Morganza Spillway doesn't offer much relief to people upstream, where it has little to no effect on flood levels. "Opening a spillway or levee only aids in easing the flooding downstream along the river's banks," explains AccuWeather meteorologist Kristina Pydynowski. So while the Mississippi River is expected to crest this week at 45 feet in Baton Rouge and 17 feet in New Orleans, it's poised to top out at 63.5 feet Saturday in Natchez, Miss. — well above the previous record of 58.04 feet set back in 1937. Up to 5,000 people in Mississippi have evacuated or will evacuate as the floods spread, Reuters reports.

(Sources: CNN, New Orleans Times-Picayune, AccuWeather, Reuters)

SQUID IN SPACE 

The space shuttle Endeavour is soaring through Earth's orbit today, making its last-ever approach to the International Space Station, where it's scheduled to dock Wednesday. And while the shuttle's six-man crew has gotten lots of media attention — especially shuttle commander Mark Kelly, husband of injured U.S. Rep. Gabrielle Giffords — there are other occupants aboard the spacecraft that have been largely overlooked. Among them are a baby bobtail squid, a microscopic creature called a "water bear" and five other types of microorganisms.

Endeavour's most widely reported mission is to deliver the $2 billion Alpha Magnetic Spectrometer to the space station, which will help scientists study the universe's origins and search for evidence of dark matter and antimatter. But the shuttle is also carrying several other science experiments into space, including one that has made the bobtail squid (pictured above) the first cephalopod in space, Wired reports. That experiment isn't so much about the squid itself, but about the beneficial bacteria living on its body. Since some types of harmful bacteria tend to grow even deadlier when taken into space — salmonella, for example, become three times more likely to kill their hosts, even after returning to Earth — researchers are curious to see how helpful species like those living on the bobtail squid respond to leaving their home planet.

Another experiment aims to find out just how hardy the so-called "hardiest animal on Earth" really is. Often dubbed "water bears," the microscopic creatures called tardigrades have been to space before, hitching a ride on a European mission in 2007 and becoming the first animal to survive unprotected in the vacuum of space. Based on that exposure, the Endeavour crew will expose colonies of tardigrades to different levels of ionizing radiation so scientists can examine how radiation dosage in space affects their cells' functioning. Tardigrades are found all over Earth in both fresh and salty water, and are capable of entering a state called "cryptobiosis," in which they can withstand both freezing and severe dehydration. By finding out what else they can survive, scientists hope to learn lessons that could one day be useful to humans on long-term voyages into deep space.

(Sources: Wired, BBC News, Space.com)

ENLIGHTENING 

What if you could suppress anxiety, depression or even involuntary muscle spasms by switching on a tiny light in your brain? Researchers at Stanford University say they've invented a technique that could one day make that possible, along with countless other psychiatric treatments that are beyond the reach of today's blunt pharmaceutical drugs. In a study published in the journal Nature, they describe how they turned timid mice fearless, making them instantly stop cowering and wander around their cages.

The sci-fi-sounding technique involves taking light-sensitive genes from pond scum, packing them into viruses that have been engineered to be harmless, and using those viruses as "disposable molecular syringes" to inject the pond-scum genes into specific brain cells. The genes' light-sensitive proteins, called "opsins," then become part of the brain cells, allowing them to be controlled remotely with light. To do that, researchers simply insert thin optical fibers through layers of nervous tissue, positioning them within the brain so they can shine a certain color of light onto the given cluster of neurons. Different opsins respond to different colors of light, sometimes activating a cell's function and sometimes deactivating it — giving researchers a high degree of control over individual brain cells. And if the light-sensitive genes were inserted into brain cells known to govern certain moods or behaviors, this creates a virtual on/off switch.

In addition to its promise in solving a wide array of mental and physical disorders in humans, the technique — part of a novel field called "optogenetics" — reveals flaws with the current use of pharmaceutical drugs, the researchers say. "Psychiatric disorders are probably not due only to chemical imbalances in the brain," study co-author Jaime Anderson tells the New York Times. "It's more than just a giant bag of serotonin or dopamine whose concentrations sometimes are too low or too high. Rather, they likely involve disorders of specific circuits within specific brain regions." But since it seems unlikely many humans would be game for such an invasive brain overhaul, the researchers are studying ways to achieve similar effects by stimulating the brain's surface instead of placing fiber optics deep inside.

(Source: New York Times)

DYING TO KNOW 

A controversial new blood test that can tell how much longer a person will live is set to hit the market in Britain within a year, PhysOrg reports, potentially wreaking havoc with everything from preventive medicine to the health and life insurance industries. The test works by measuring a person's telomeres, tiny structures on the tips of chromosomes that are thought to be key indicators of how quickly a body is aging. Telomeres (the white dots in the photo above) are often compared to the plastic caps on shoelaces: As they wear down over time, the shoelace — or chromosome — becomes more likely to unravel.

The new blood test was developed by Maria Blasco at the Spanish National Cancer Research Center, PhysOrg reports, and Blasco's company, Life Length, is now in talks with medical-diagnostics companies across Europe to collect blood samples and begin marketing. The test isn't capable of providing a precise remaining life span in terms of months or years, but simply offers a relative picture based on observed telomere lengths. Research has shown that people with shorter telomeres are essentially farther along in the aging process, regardless of their actual age, and thus have a shorter life span than people whose telomeres are more intact. Scientists hope the study of telomeres in general can eventually yield important information on age-related ailments such as Alzheimer's, cancer and heart disease.

But there are potential problems with a blood test that predicts life span: Critics point out that life and health insurance companies would be very interested in obtaining that information, which would help them more accurately assess the health of their customers. Life insurance companies may even press for mandatory testing of policy holders, and those with shorter telomeres would presumably face a harder time getting insured. Other critics worry that overly focusing on telomeres could lead to scams and miracle cures that take advantage of people with shorter telomeres.

(Source: PhysOrg)

THIS DAY IN HISTORY

Experimental forest set up in New England, Pete Seeger christens "Clearwater" sloop, and more.

Russell McLendon

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Photo (flooding in Vicksburg, Miss., on May 16): ZUMA Press

Photo (adult bobtail squid): Hans Hillewaert/Wikimedia Commons

Photo (fiber optics): National Institute of Standards and Technology

Photo (chromosomes with telomeres): NASA Science

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