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16 | NewScientist | 2 July 2011 SOME black holes keep a tight hold on everything, even their own vital statistics. Now Cygnus X-1, the first black hole discovered, has divulged its distance from Earth and in turn its weight – and that it was born spinning. Cygnus X-1 was identified as a likely black hole in 1972, but its distance from Earth has been maddeningly difficult to pin down. This in turn has made it hard to determine basic properties like its mass and spin. Mark Reid of the Harvard- Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and colleagues used the Very Long Baseline Array of radio telescopes spanning the US to measure the object’s parallax – tiny shifts in its apparent position due to Earth’s motion around the sun. Based The hidden stress of ecotourism ECOTOURISTS are doing monkeys no favours by sharing their picnic with them. Wildlife tourism is already thought to stress many species. To study its effect on Barbary macaques (Macaca sylvanus) in the Moroccan Atlas mountains, Laëtitia Maréchal and Stuart Semple of the University of Roehampton, London, recorded levels of glucocorticoid hormones – an indicator of stress – in the monkeys’ faeces. They also monitored rates of self-scratching, which relates to anxiety. The researchers found that even something as seemingly innocuous as taking a photo or feeding the macaques increased the likelihood of anxiety, while aggression from tourists pushed them into full-blown stress (Biological Conservation, DOI: 10.1016/j.biocon.2011.05.010). Such studies are vital to help establish guidelines, says Semple. Finches’ tweets knock humans off their perch HUMANS may not be the only species to have rules of syntax dictating how words can and cannot be put together. The songs of Bengal finches appear to have similar grammatical rules. “Songbirds have a spontaneous ability to process syntactic structures in their songs,” says Kentaro Abe of Kyoto University, Japan, who has been putting the birds’ grammatical abilities to the test. In the wild, Bengal finches call back vigorously when they hear unfamiliar songs, usually from intruding finches. In the lab, Abe and colleague Dai Watanabe of the Japan Science and Technology Agency in Saitama ARCO IMAGES GMBH/ALAMY IN BRIEF Famous black hole reveals vital statistics on the size of the shifts, Cygnus X-1 is 6000 light years away, give or take a few hundred light years, the team reports (arxiv.org/ abs/1106.3688). Combining this measurement with other information revealed a rapid spin rate and the mass of the black hole to be 14.8 times the sun’s (arxiv.org/abs/1106.3689). It was likely born in a spin as it would not have had enough time to “spin up” by stealing gas from its companion star. gauged the birds’ sense of syntax by playing jumbled “ungrammatical” remixes of finch songs to the birds and measuring the response calls. One way they did this was by playing unfamiliar songs repeatedly until the birds got used to them and stopped overreacting. They then jumbled up syllables within each song and replayed these versions to the birds. The birds reacted to only one of the four jumbled versions, as if they noticed it violated some rule of grammar, whereas the other three remixes didn’t. Almost 90 per cent of the birds tested responded in this way (Nature Neuroscience, DOI: 10.1038/nn.2869). “This indicates the existence of a specific rule in the sequential orderings of syllables in their songs, shared within the social community,” Abe says. DEADLY snake-bite venom could be slowed on its way into the blood by a cream applied to the bite site, giving victims time to seek help. Snake bites penetrate tissue, not blood vessels, so most of the toxins enter the blood via the lymphatic system. To slow this journey, Dirk van Helden at the University of Newcastle at Callaghan, Australia, and colleagues applied nitric oxide cream – which stops the pumping of the lymphatic system – to mice injected with venom. The cream increased the time it took the venom to reach the blood supply from 65 to 96 minutes (Nature Medicine, DOI: 10.1038/nm.2382). This would buy bite victims around 50 per cent more time to seek treatment, says van Helden. Cream slows snake venom’s invasion
