内容摘要：Mr Tucker said: "We know my uncle was a great admirer of Burra's – but my dad thinks his brother may have also travelled to the area for work.

Mr Tucker said: "We know my uncle was a great admirer of Burra's – but my dad thinks his brother may have also travelled to the area for work.

The second seed will face another American, Tommy Paul, in the last eight after the 12th seed beat Australia's Alexei Popyrin 6-3 6-3 6-3.Having said he "didn't enjoy" his battling win over Damir Dzumhur in the third round, Alcaraz was far closer to his best on Sunday and had to be against the big-hitting Shelton.

The first set headed to a tie-break after only one unconverted break point for the favourite, but it was Shelton who initially gained the upper hand.With the crowd roaring their approval as the pair played out a number of stunning points that saw both players at the net, Alcaraz was forced to stave off three set points.Having done so, the four-time Grand Slam champion took the tie-break but was immediately under pressure in the second set.

Shelton earned six break points in the opening game but was denied each time by Alcaraz, who turned it on late in the set to claim the crucial break.But Shelton was far from done and after the duo exchanged breaks early in the third set, the 22-year-old from Atlanta saved a break point for a big hold at 4-4.

A helpful net chord gave him two set points in the next game and he took the second to pile the pressure on his Spanish opponent.

Alcaraz quickly regrouped though and broke for a 2-1 lead early in the set. While the pair continued to exchange eye-catching shots, this time Shelton was unable to find a way back.Manuel chips in enthusiastically with an impish grin, saying that the new systems that he too firmly believes will emerge will be the "next stage in humanity's evolution".

Conscious robots, he believes, "are our progeny. Down the road, machines like these will be entities that will be on Earth and maybe on other planets when we are no longer around".David Chalmers – Professor of Philosophy and Neural Science at New York University – defined the distinction between real and apparent consciousness at a conference in Tucson, Arizona in 1994. He laid out the "hard problem" of working out how and why any of the complex operations of brains give rise to conscious experience, such as our emotional response when we hear a nightingale sing.

Prof Chalmers says that he is open to the possibility of the hard problem being solved."The ideal outcome would be one where humanity shares in this new intelligence bonanza," he tells the BBC. "Maybe our brains are augmented by AI systems."