The space shuttle Endeavour won't begin its final mission for at least another week, Space.com reports, as NASA needs more time to repair damage to the orbiter's auxiliary power unit. Originally scheduled for Friday afternoon, the launch was called off when shuttle engineers discovered the damage a few hours before liftoff, delaying what will eventually be a historic flight for the retiring shuttle. For now, the agency says May 8 is the earliest date it's considering for a do-over. "Right now we're not ready to set a launch date," Mike Moses, chair of the shuttle's mission management team, said Sunday. "We know right now that the 8th is our next available opening."
The postponement not only delayed a dramatic moment for NASA's retiring shuttle fleet, but also for attending dignitaries such as U.S. Rep. Gabrielle Giffords and President Obama (although it's now clear the president had bigger fish to fry
this weekend anyway). Giffords, who is recovering from a gunshot wound to the head she suffered in January, had flown from Houston to Cape Canaveral to watch her husband, shuttle commander Mark Kelly, launch into space. She has returned to Houston for now, and it's unknown whether she'll make the trip to Florida again, the AP reports. The White House also hasn't announced yet whether the first family will attend the rescheduled launch, although President Obama did hint that he might return to see the launch of Atlantis, the very last NASA shuttle, later this summer.
Endeavour is slated to carry Kelly and five other astronauts up to the International Space Station for a two-week trip, largely to deliver a $2 billion particle detector designed to help researchers study dark matter and other cosmic mysteries. Friday's launch attempt was canceled after NASA discovered malfunctioning heaters in three of the shuttle's auxiliary power units, a problem that could have let the units freeze in orbit, rendering a crucial flight system useless. Engineers spent the weekend studying the glitch, finally tracing it to a control box called the "aft load control assembly-2," which will now require extensive repairs and testing to ensure the shuttle is safe, Space.com reports. "We need to go in and change out that box," Moses said Sunday. "Once the box comes out we have to verify circuitry and prove the box itself was the failure. We still have a lot of work." Still, he added, if there's one thing NASA has become good at during its 30-year shuttle program, it's solving unexpected problems like this. "Responding to problems is one of the things we do best around here," Moses said, "and the team always likes a good challenge."
With the death toll from last week's devastating U.S. storms now at roughly 350 — making it the country's deadliest tornado outbreak since 1925 — people across the Midwest and Southeast are already bracing for even more trouble. The Mississippi River and other Midwestern waterways are poised for historic flooding as more storms arrive in the region, AccuWeather reports, potentially dumping another 3 to 5 inches through Tuesday.
The 2,800 residents of Cairo, Ill., have already been evacuated in anticipation of the flooding, Reuters reports, with the nearby Ohio River standing at a record-high 59.97 feet Sunday afternoon. It's expected to rise beyond 60 feet in the coming days, one of several rivers on the verge of unprecedented floods. The U.S. Army Corps of Engineers continues to push for a plan to save Cairo by blowing up a levee near Birds Point, Mo., flooding some 130,000 acres of farmland and destroying dozens of homes in hopes of reducing the burden on the Ohio River. A federal appeals court on Saturday affirmed the Corps' right to breach the levee, per a 1928 law, but Missouri officials asked the U.S. Supreme Court on Sunday to intervene, arguing the levee breach would cause excessive harm to the local economy. Illinois and Kentucky have sided with the Corps, however, saying towns in their states could be inundated if they levee is left intact.
Heavy rains began falling Sunday in parts of the Ohio and Mississippi valleys, and are forecast to continue through Tuesday morning; at that point, the National Weather Service says the Ohio River could crest at 60.5 feet, a full foot above its 1937 record. "The stress on the levees in some locations will not only last days, but weeks, as huge rivers such as the Mississippi and Ohio take much longer to fall below flood stage than smaller rivers, even as heavy rain comes to an end," says AccuWeather meteorologist Alex Sosnowski.
Tilapia is everywhere these days, having quickly become the go-to species for anyone who needs large volumes of cheap, appealing (albeit a bit bland) fish filets. Surging from relative obscurity in just a decade, tilapia is now the most popular farmed fish in the U.S., the New York Times reports, with Americans eating 475 million pounds of it in 2010, four times the amount consumed 10 years ago. But while the rise of this African lake fish may be good news for many reasons — letting more people eat fish affordably, and possibly displacing less healthy meats like beef or pork — it's not without nutritional and environmental downsides, the Times points out.
Tilapia contains small amounts of beneficial omega-3 fatty acids compared with other fish, undermining one of the main health benefits that leads doctors to recommend that people eat fish frequently. Salmon, for example, has more than 10 times the amount of omega-3s. And the fatty acids tilapia does contain are typically of a less nutritious variety, the Times adds, since aquaculture farms use corn and soy pellets to feed the fish instead of lake plants and algae, their natural food sources in the wild. "It may look like fish and taste like fish, but does not have the benefits — it may be detrimental," fish-lipid expert Floyd Chilton tells the Times. Plus, intensive tilapia farming in Latin America and Asia is said to be harming ecosystems with practices that are banned in the U.S., such as large-volume caged breeding in natural lakes. Such farming techniques can contaminate lakes with fish waste, and also threaten to release even more of an already-invasive species. "We wouldn't allow tilapia to be farmed in the United States the way they are farmed here, so why are we willing to eat them?" says a U.S. fish biologist who works in Nicaragua. "We are exporting the environmental damage caused by our appetites."
While tilapia farming may have grown more quickly than some countries' environmental regulations could keep up, the Times adds that the industry says it's now improving standards. The Aquaculture Stewardship Council is working on an inspection protocol for tilapia farms that's independent of the industry itself, for example, allowing qualified growers to label their fish as "responsibly farmed." And while many environmentalists remain critical of fish farming in general, University of Arizona biologist Kevin Fitzsimmons argues that the dominance of aquaculture is inevitable. "There are going to be more farmed fish each year," he says. "Think about it: If we tried to get beef from hunting, there would be a lot of hungry people."
Farmers have spent centuries trying to kill crop-eating insects without killing their crops — or beneficial insects like honeybees — with limited success. But according to a new study published in the Journal of Biological Chemistry, scientists may have found an unlikely ally from the insect world: scorpions. Researchers already reported
earlier this year that scorpion venom can be useful in creating pesticides, and now scientists from Michigan State University say they've begun unraveling the mysteries of how this potent natural toxin works — and how it can be manipulated.
"Interestingly, some scorpion toxins selectively affect one type of sodium channels, but not others," says study author Ke Dong. "The goal of our scorpion toxin project is to understand why certain scorpion toxins act on insect sodium channels, but not their mammalian counterparts." Scorpion venom attacks various channels and receptors in their victims' nervous and muscular systems, including the voltage-gated sodium channel, which is used for rapid-fire electrical signaling in nerve and muscle cells. Dong and his colleagues identified amino-acid residues in insects' sodium channels that make the bugs more susceptible to scorpion venom, specifically that of the Israeli desert scorpion. They also found that a specific voltage sensor in the sodium channel can affect how deadly the scorpion venom is.
"Investigating the venom's effect on the voltage-gated sodium channel could provide valuable information for designing new insecticides that work by selectively targeting insect sodium channels," Dong says. Many currently available types of pesticides act on insects' sodium channels, but the pests can gradually become resistant to them over time. By studying how insects develop this resistance, Dong also hopes to create alternatives that can help control crop-detroying pests.
The Hudson's Bay Company is created, residents of Centralia, Pa., fight eviction, and more
Photo (Endeavour in Cape Canaveral, Fla., on April 29): ZUMA Press
Photo (flooding on the Mississippi River in May 2010): Jim Suhr/AP
Photo (tilapia): U.S. Geological Survey, South Florida Information Access
Photo (scorpion): Tennessee Department of Environment and Conservation