Most of us assume that by the time food arrives at the grocery store, it’s been checked for any chemicals that might harm us. That’s not necessarily the case: food manufacturers and federal employees test for some known culprits in some foods, but the search isn’t exhaustive, especially when it comes to imported items. Recently, scientists working with ABC News checked to see whether imported farmed shrimp bought from grocery stores had any potentially dangerous antibiotic residue, left over from the antibiotic-filled ponds in which they are raised. It turns out, a few of them did.
Out of 30 samples taken from grocery stores around the US, 3 turned up positive on tests for antibiotics that are banned from food for health reasons. Two of the samples, one imported from Thailand and one from India, had levels of carcinogenic antibiotic nitrofuranzone that were nearly 30 times higher than the amount allowed by the FDA. The other antibiotics the team discovered were enroflaxin, part of a class of compounds that can cause severe reactions in people and promote the growth of drug-resistant bacteria, and chloramphenicol, an antibiotic that is also a suspected carcinogen.
It’s easy to see how overwatering our crops would deplete the groundwater supply and cause land nearby to sink, but could it cause sea level to rise on a global scale? Yes, according to a model published in Nature Geosciences, that attributes 42% of the sea-level rise over the past half century to groundwater use.
Ninety percent of readily available freshwater is underground, and water used for drinking or crop irrigation must, of course, be brought above ground. That water then evaporates or flows into rivers, entering the water cycle and eventually the oceans, making them deeper.
DNA is a great way to store information—just ask your cells. Its molecules are stable, and billions of base pairs coil neatly into a few microns in a cell nucleus. While it’s easy for a cell to read information from DNA, a cell can’t rewrite new data into its DNA sequence.
But now synthetic biologists at Stanford have managed to pull off that very trick. To do so, they had to abandon the genetic code of ATCG and get a DNA sequence to act like bits—pieces of binary information—in a computer. The memory system uses two enzymes that can cut out and reintegrate a sequence of DNA in a live cell. Crucially, the attachment sites are designed so that the DNA sequence can be flipped every time it is put back in. The sequence oriented one way would represent 1, and its inversion is 0.
It’s been a rocky few years for spaceflight. NASA’s budget isn’t getting any bigger. And though the Space Shuttle program was expensive, dangerous, and kept better designs from being developed, once it ended last year, US astronauts have had to hitch rides on Russian rockets, which are themselves not too reliable. But this morning’s launch of SpaceX’s first International Space Station supply rocket was a bright spot.
NASA is betting on the private sector to bring about the next great space age. It has made grants to various private space flight companies, including PayPal founder Elon Musk’s Space Exploration Technologies, colloquially known as SpaceX, to develop space taxi technologies and supply the International Space Station.
And early this morning, after an aborted launch attempt on Sunday, SpaceX’s first rocket left Earth, carrying a capsule bound for the space station. You can watch the unmanned vehicle take off in the video above, and you can hear in the excitement in the NASA launch commentator’s voice as the fiery ship takes off through the night.
Flares have been washing up on beaches for a long time:
an AP news item from February 23, 1993
Last week, several small stones in the pocket of a California woman’s shorts exploded into flame, leaving her with third-degree burns. The stones came from a beach at San Onofre State Beach in San Diego, which she’d visited earlier in the day.
The story caused a sensation, as media discussed what could make rocks catch on fire. By Friday, California environmental health officials had an answer, or at least part of one: two of the rocks were covered in phosphorus, an element that’s known for igniting into a fierce white flame when it’s exposed to air. Near as they can tell, as long as the rocks were wet with seawater, the phosphorus didn’t ignite, but after they’d dried out in the woman’s pockets over the course of the day, the phosphorus reacted explosively.
But how did the rocks get covered with phosphorus? Though the substance is mined and used in fertilizers, it isn’t very common in in the natural world in its explosive form, called white phosphorus. White phosphorous does, however, have a long history of production by militaries, who use it in flares. Unexploded military flares, presumably dropped by aircraft, have been known to wash up on beaches: Just last year flares washed up on a beach a half-hour’s drive from San Onofre. NBC reported that those flares were from military exercises going on off the coast.
The NIH National Children’s Study was launched in 2000 with much fanfare and an important mission: to follow a hundred thousand of American children from birth to age 21 and collect data on the environmental, chemical, physical, and psychosocial factors affecting them, with an eye towards understanding diseases that start in childhood, including autism, diabetes and asthma.
Now, however, the study has been deemed too expensive to continue in the same form—so far, only about 4,000 children have been enrolled, at a cost of a billion dollars. While it makes sense to look into bringing the costs down, one of the NIH’s money-saving strategies is in danger of compromising the study’s statistical usefulness: instead of continuing to recruit children from all over the country, the NIH is proposing working with health maintenance organizations, or HMOs, to gather the remaining data. This move would mean that children in rural areas, which tend not to be served by HMOs, would be excluded, and the mountains of data the study is poised to gather would not be complete. Already, two advisory board members have resigned in protest of this proposed policy.
Given all the time and money have already been invested in the study, these changes are a big deal. To find out more about the National Children’s Study controversy, and learn about what’s happening next, check out Nature News‘ thorough coverage.
Image courtesy of leean_b / flickr
A few days ago, we wrote about a remarkable graphic released by the USGS, showing all the water on Earth—freshwater, saltwater, water vapor, water in plants and animals; all of it—rolled into a sphere.
That sphere was only 860 miles in diameter, fitting comfortably between Salt Lake City and Topeka, Kansas, on a map. It was striking, especially considering that the water available for humans use in our daily lives is only a very small fraction of that; the vast majority of the Earth’s water is saltwater, and most of the freshwater is tied up in glaciers.
How big would a sphere of just the freshwater available to humans be? Reader Jay Kimball of 8020Vision, his interest piqued, went ahead and made such a graphic:
That sphere—the sphere representing the freshwater available to humans—has a diameter of just 170 miles. Head to his blog to see the math.
Last week, a video of this mysterious blob floating 5000 feet under the sea was all over the Internet. Was it a whale placenta? A jellyfish? After some collective ooing and aahing, folks on the interwebs put their thinking hats on. Craig McClain at Deep Sea News dug through the literature and found a 1988 paper describing just such a jellyfish, calling it Deepstaria reticulum.
Now the Monterey Bay Aquarium Research Institute has posted a stunning video of Deepstaria jellyfish. Watch it to learn more about Deepstaria—and to look at pretty images. Win win for a Friday afternoon.
[via Deep Sea News]
A recent study suggesting a link between coffee drinking and longer lives has prompted a flurry of coverage—some snarky, some cautious, but mostly celebratory. (We see you there, reaching for another cup of coffee.)
The study published at the prestigious New England Journal of Medicine is about as good as observational epidemiology studies go, but it’s limited by virtue of being observational. Last month on our Crux blog, Gary Taubes wrote a hard-hitting piece about the problems with observational studies. A major limitation of surveying people about their lifestyle habits is that correlation does not imply causation. It can’t prove coffee drinking actually led to living longer. There are always confounding variables. Read More
FA=high-fat, ab libitum (eat-at-will) diet, FT=high-fat, time-restricted diet, NA=normal ab libitum (eat-at-will) diet, NT=normal diet, time-restricted
Diets tell you what you eat, but a new study suggests when you eat matters too. Of two groups of mice who were fed the same high-fat diet, the mice who could eat around the clock were much heavier than those who had food restricted to eight hours per day, in a new study published in Cell Metabolism.
Researchers in the study gave the mice a special high-fat chow, 61% of whose calories come from fat (compared to just 13% in normal feed). The mice who chowed down all day and night became, unsurprisingly, obese, but the ones who ate the same amount of hi-fat food in only eight hours per day did not. Their body weight was comparable to mice fed an equivalent amount of calories on normal feed.