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on his site frequently complained to senior a problem. Ideally, every entry on the list would Rick Anderson, an associate dean in the officials at his institution. state reasons for its inclusion, agrees the anony- library at the University of Utah in Salt Lake Last June, a scholarly-services firm called mous site manager. “I’m not sure if I will ever City, says that the scholarly community Cabell’s International in Beaumont, Texas, have to do that myself,” they say. does need a good list of predatory publish- launched a pay-to-view blacklist of journals Berryman says that around 200 institutions ers (Anderson did paid consulting work for it deems ‘deceptive’, listing criteria for decid- have subscribed to Cabell’s blacklist since its Cabell’s when it was planning its blacklist). ing whether titles should be added. Kathleen launch. The list contains about 8,000 journals, But it should include clear criteria and justifi- Berryman, a project manager at the firm, says including some that aren’t open access. (The cations for inclusion, explanations for removed that a lack of clear explanations for why journals firm also maintains a whitelist; some journals entries and an appeal system, he says. “To do are on the anonymously maintained blacklists is aren’t on either list, Berryman says.) it well is going to be expensive and difficult.” ■

PEOPLE World’s scientists pay tribute to The physicist and science icon died at his home in , UK, aged 76.

BY DAVIDE CASTELVECCHI holes were not truly black. This emission, he reasoned, should tephen Hawking, one of the most ultimately lead a to shrink and influential physicists of the twenti- disappear (S. W. Hawking 248, eth century and perhaps the most 30–31; 1974). Even more shocking to TOM PILSTON/PANOS TOM Scelebrated icon of contemporary science, researchers was Hawking’s realization in died on 14 March at the age of 76. 1976 that should erase Since his early twenties, Hawking had information from the , in appar- lived with amyotrophic lateral sclerosis ent contradiction to some of the basic (ALS), a disease in which motor neu- tenets of quantum theory (S. W. Hawking rons die, leaving the brain incapable Phys. Rev. D 14, 2460–2473; 1976). “The of controlling muscles. His health had importance of this work was not so much reportedly been deteriorating. the effect itself, but that he was able to pro- Hawking’s death was marked by vide the one clear-cut physical implication tributes from scientists worldwide. “The that we know of which brings together reaction among physicists is just profound the two great revolutions of twentieth- shock and sadness,” says Malcolm Perry, century , namely, a theoretical physicist at the University of and ,” says Penrose. Cambridge, UK, and a student of Hawk- Two years ago, together with Perry ing’s in the early . “He was a truly and at Harvard Uni- extraordinary man,” says , versity in Cambridge, Massachusetts, a theoretical physicist at the University of Stephen Hawking, giant of , in 2013. Hawking began to sketch a possible way , UK, who in 1970 co-authored a out of the black-hole information para- seminal paper with Hawking on black holes. became one of the most recognized names in dox. The three of them, along with Strominger’s Another former student, theoretical contemporary science. His books, particularly student Sasha Haco, had been working on a physicist at the University of A Brief History of Time (1988), became block- follow-up paper, which Perry says is in its final California, Berkeley, told Nature that his teacher buster successes. He relished making cameo stages and will have Hawking’s name on it. was a brilliant physicist who also excelled at appearances on television shows such as Star Perhaps because most of his work was of a communicating science to the public. “Stephen Trek: The Next Generation and . speculative nature and difficult to test, Hawk- was a joyful and -hearted person, not to be Scientifically, his name is most closely associ- ing never won a Nobel prize. In 2016, some burdened by excessively respectful and convo- ated with the physics of black holes, which he wondered whether he might finally win one, luted interactions,” he says. began to study when they were considered mere when Jeff Steinhauer, a physicist at the Tech- The British physicist was born in Oxford in mathematical curiosities in ’s nion–Israel Institute of Technology in Haifa, 1942. He was diagnosed with ALS when he was general . In the early 1970s, announced that he had found convincing evi- 21, while a doctoral student in cosmology at the he began to investigate what quantum physics dence of Hawking radiation — not in an actual . Physicians gave him could reveal about the horizon, a black black hole, but in a laboratory analogue made just a few years to live, but his disease advanced hole’s surface of no return. Hawking shocked of ultra-cold atoms. However, some experts more slowly than expected. He had an active the physics world when he calculated that this still consider those results inconclusive. career for decades, both as a theoretical physi- surface should slowly emit radiation (soon to A more direct test of some of Hawking’s cist and as a popularizer of science. Hawking become known as Hawking radiation). Black findings might yet come from the study of

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astrophysical black holes through gravita- from merging black holes, Hawking said that also explored cosmic — a brief period tional waves, initiated by the US-based Laser he hoped future detections would be sensitive of rapid expansion in the first moments of the Interferometer Gravitational-wave Observa- enough to confirm a prediction he had made in — and how it could spawn several tory (LIGO). Hawking and others have linked the 1970s: that the surface area of a post-merger , a ‘’. The pair set out to the surface area of a black hole’s to black hole should exceed the combined surface transform the idea of a multiverse into a test- its , a measure of disorder. When inter- areas of the original objects that formed it. able scientific framework, says Hertog. “This viewed by Nature’s news team in 2016 about Together with cosmologist , was Hawking: to boldly go where LIGO’s first detection of gravitational waves another of his former students, Hawking had fears to tread.” ■ SEE OBITUARY P.444

PALAEOANTHROPOLOGY creatures. “It’s a one-two punch combining tectonic shifts and climate shifts,” says Rick Potts, who led the work as director of the human origins programme at the Smithsonian Surprise roots for Institution in Washington DC. “That’s the kind of stuff out of which evolution arises.” The studies push back the timeline for such behaviour by around 100,000 years, adding to human culture a growing body of evidence suggesting that the roots of human culture are deeper and more extensive than thought. Technology developments linked to climate turbulence. The latest evidence is “probably not enough to put the question to rest as to what effect the BY JEFF TOLLEFSON simple hand axes in favour of smaller and more climate variability had on human behaviour”, advanced blades made from obsidian and other says Nick Blegen, an anthropologist at the arly humans in eastern Africa crafted materials obtained from distant sources. That Max Institute for the Science of Human advanced tools and displayed other shift suggests the early people living there had History in Jena, Germany. But he says that the complex behaviours tens of thousands developed a trade network — evidence of grow- findings from Olorgesailie provide solid evi- Eof years earlier than previously thought, ing sophistication in behaviour. The research- dence for a shift towards sophisticated behav- according to a trio of papers published on ers also found gouges on black and red rocks iour that predates the earliest evidence for Homo 15 March in Science1–3. Those advances coin- and minerals, which indicate that early Olorge- sapiens. Researchers have traditionally thought cided with — and may have been driven by — sailie residents used those materials to create that H. sapiens emerged around 200,000 years major climate and landscape changes. pigments and possibly communicate ideas. ago, but fossils discovered in Morocco could The latest evidence comes from the push that date to more than 300,000 years ago4. Olorgesailie Basin in southern Kenya, where A TIME OF CHANGE Blagen has documented the transport of researchers have previously found traces of All of these changes in human behaviour obsidian in central Kenya roughly 200,000 years ancient relatives of modern human as far back occurred during an extended period of envi- ago5, and he is preparing another study that as 1.2 million years ago (see ‘Complex lives’). ronmental upheaval, punctuated by strong would push that record back to 396,000 years Evidence collected at sites in the basin sug- earthquakes and a shift towards a more vari- ago at the same site. The record for such com- gests that early humans underwent a series able and arid climate. These changes occurred plex behaviour is likely to extend back even of profound changes at some point before at the same time as larger animals disappeared further, he says, but it is not clear whether the roughly 320,000 years ago. They abandoned from the site and were replaced by smaller environment is shaping human behaviour, or whether advances in human behaviour are enabling them to inhabit riskier environments. COMPLEX TOOLS Excavations in the Olorgesailie Basin have been turning up Stone Age artefacts ever since Louis and Mary Leakey pioneered work there in the 1940s. But this is the first time that scientists have documented evidence of more advanced tools and behaviours typically asso- ciated with the Middle Stone Age, which lasted

until 25,000–50,000 years ago, says Alison HUMAN ORIGINS PROGRAMME, SMITHSONIAN Brooks, an anthropologist at George Wash- ington University in Washington DC, who led the dating and analysis of the latest artefacts. Isotopic dating techniques helped the team to pin down the age of the stone tools, and the researchers traced the obsidian back to its sources, which were mostly located 25–50 kilometres away in multiple directions. “It’s the best evidence yet for the exchange of raw materials” so early in time, Brooks says. Simpler tools (left) gave way to smaller and more complex versions (right) in Kenya’s Olorgesailie Basin. Curtis Marean, a palaeoanthropologist at the

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