A roundup of the good, the bad and the just plain interesting from the week's science headlines.
An international team of scientists has developed a way to see breast scans in 3-D, using less radiation than what's used in clinics to produce two-dimensional images. The mammography method typically used only captures two images of breast tissue, the researchers said in a press release. Computer tomography – a CT scan – takes a 3-D picture, but emits too much radiation to be regularly used on sensitive breast tissue. However, researchers used high energy X-rays (which leave less radiation behind), along with a method that reduces the number of X-ray beams needed to create an image, to take hundreds of pictures of a breast. Scientists then use an algorithm to build a 3-D picture from those images. The radiation dose used is about 25 times lower than in the standard procedure, and the team hopes it will help catch the 10 to 20 per cent of tumours not seen on standard mammograms. The research was published Monday in the Proceedings of the National Academy of Scientists. – Aleysha Haniff
Radioactive cesium levels in most kinds of fish caught off the coast of Fukushima, Japan haven't declined in the year following Japan's nuclear disaster, a signal that the sea floor or leakage from the damaged reactors must be continuing to contaminate the waters — possibly threatening fisheries for decades, a researcher says.
Though the vast majority of fish tested off Japan's northeast coast remain below recently tightened limits of cesium-134 and cesium-137 in food consumption, Japanese government data show that 40 per cent of bottom-dwelling fish such as cod, flounder and halibut are above the limit, Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institution in Massachusetts, wrote in an article published Thursday in the journal Science.
"The [radioactivity] numbers aren't going down. Oceans usually cause the concentrations to decrease if the spigot is turned off," Buesseler said. "There has to be somewhere they're picking up the cesium.
"Option one is the sea floor is the source of the continued contamination. The other source could be the reactors themselves," he said. – The Associated Press
- Some African beetles have a cool reason for rolling balls of dung, according to research published Tuesday in Current Biology. Scientists at Lund University noticed the insects would crawl onto their dung balls more often when walking across scorching desert sand, climbing onto the waste seven times more often on hot ground compared to cool ground. The beetles rubbed their head and front legs on the balls to beat the heat– scientists noted the surface temperature of the beetles’ legs rose as much as 10C while the creatures rolled the dung balls, and decreased by 7 C on average within 10 seconds after climbing onto the ball. The beetles also wore insulated ‘boots’ to test the hypothesis, and scientists said the insects rolled the ball for nearly twice as long on the hot surface and climbed the ball 35 per cent less. – Aleysha Haniff
- The ostrich-like dinosaurs that roamed the Earth millions of years ago were adorned with feathers, used to attract a mate or protect offspring rather than for flight, according to the findings of Canadian scientists released on Thursday. Researchers from the Royal Tyrrell Museum of Palaeontology and the University of Calgary made the discovery in the 75-million-year-old rocks in the badlands of southern Alberta. The ostrich-like dinosaurs, known as ornithomimids, were thought to be hairless, fleet-footed birds and were depicted as such in the Hollywood movie Jurassic Park. But the researchers found evidence of feathers with a juvenile and two adult skeletons of ornithomimus, a species within the ornithomimid group. “The discovery, the first to establish the existence of feathers in ornithomimids, suggests that all ostrich-like dinosaurs had feathers,” according to a statement from the Alberta museum. – Reuters
- Scientists in Oregon have created embryos with genes from one man and two women, using a provocative technique that could someday be used to prevent babies from inheriting certain rare incurable diseases. The researchers at Oregon Health & Sciences University said they are not using the embryos to produce children, and it is not clear when or even if this technique will be put to use. British experiments, reported in 2008, led to headlines about the possibility of babies with three parents. That’s a bit of an overstatement: the DNA from the second woman amounts to less than 1 per cent of the embryo's genes. Instead, the procedure is viewed as a way of replacing some defective genes. The British government is asking for public comment on the technology before it decides whether to allow its use in the future. – The Associated Press