1 . When Mexican scientist of the evolution of animal behavior, Laura Cuaya, moved to Hungary for her postdoctoral studies in Budapest, she brought her pet dog, Kun-kun, along for the ride. Cuaya couldn't help noticing how locals warmed to dogs. This prompted her naturally curious scientific mind to start asking questions. “Here people are talking all the time to Kun-kun, but I always wonder if Kun-kun can recognize that people in Budapest speak Hungarian, not Spanish?” So she set out to find an answer through a scientific study.

Cuaya and her colleagues decided to use brain images from MRI scanning to shed light on her hunch. They worked with dogs of various ages that had, until the experiment, only heard their owners speak just one of the two languages, Spanish or Hungarian. Not surprisingly, getting the dogs to happily take part in the experiment took some creative coaxing and animal training! The researchers first needed to teach Kun-kun and her 17 fellow participating dogs including a labradoodle, a golden retriever and Australian shepherds, to lie still in a brain scanner. Their pet parents were always present, and they could leave the scanner at any point.

The research team played children's book classic The Little Prince in both Spanish and Hungarian while scanning the dogs' brains with an MRI machine. They were looking for evidence that their brains reacted differently to a familiar and unfamiliar language. The researchers also played scrambled versions of the story to find out if dogs could distinguish between speech and non-speech.

The images reveal that dogs' brains show different patterns of activity for an unfamiliar language than for a familiar one — the first time anyone has proved, researchers say, that a non-human brain can distinguish between two languages. This means that the sounds and rhythms of a familiar language are accessible to non-humans.

Interestingly, the team also found that the brains of older dogs were more skilled at detecting speech “suggesting a role for the amount of language exposure”. They suggest that dogs have refined their ability to distinguish between human languages over the long process of domestication.

Clean Air Act

The air in modern homes and offices is pretty clean,but not as clean as it might be.Often it contains small amounts of volatile(挥发性的）,poisonous,organic compounds.Long-term    1     to these is a bad thing,so clearing them out of the air people breathe is widely accepted as     2    

Finding an effective way to do so has proved difficult.But Stuart Strand, Long Zhang and Ryan Routsong, of the University of Washington,in Seattle,think they have succeeded,As they report in Environmental Science and Technology, their method involves     3     a gene from a rabbit into a popular indoor plant nicknamed Devil's vine—a type of ivy hat is so called because it is    4     difficult to kill.

The idea of     5     plants to de- pollute   the atmosphere inside buildings has been around for decades-but has met with only qualified success. One experiment involving unmodified spider plants,for example,showed that they are indeed     6     of removing formaldhyde (甲醛) from the air.The     7     is that to make much of a difference in a space as large as a house would require turning most of the rooms into spider-plant forests.

Dr Strand, Dr Zhang and Mr Routsong thus sought something suitably transgenic ( 转 基 因 的),but that does not flower indoors. The plant they settled on was Devil's vine,     8     because of its toughness.With the help of a bacterium,they were able to ferry the rabbit version of the gene into the plant's chromosomes(染色 体),and thus to,engineer a type of Devil's vine able to produce an air-cleaning substance. To test the     9     of their idea, the researchers put their modified ivy to work inside greenhouses filled with air containing high levels of harmful substances.The plants performed well,reducing the harmful substances in air to     10    .