What happened
US technology stocks suffered their sharpest falls in years after Democratic victories in the midterm elections raised fears that Washington could impose tighter controls on the booming artificial intelligence industry. The Nasdaq shed more than 5.5% – wiping about $2.5 trillion (£1.86 trillion) from its combined market value – while the S&P 500 dropped 4.4%.

Nvidia fell more than 9%, while AMD and Micron lost more than 17%. In total “the so-called magnificent seven tech companies, including Apple, Nvidia and Tesla, have shed a trillion dollars in value in a single trading day”, said Rachel Clun on the BBC.

Who said what
Donald Trump blamed Democrats for the market turmoil and warned supporters not to panic. Veteran progressive firebrand Senator Bernie Sanders called for a national pause on new data centres, arguing that technology companies were damaging the environment and threatening jobs.

Analysts are worried that a “divided government in Washington could lead to fewer sharp legislative changes and may make it harder to agree on fiscal spending”, said Noel Randewich and Utkarsh Hathi on Reuters.

What next?
Democrats now control both houses of Congress and are expected to pursue greater oversight of AI and restrictions on data centre development. Investors will also be watching whether the tech sell-off develops into a wider correction as concerns grow that the enormous valuations attached to AI companies may have run ahead of their prospects.

What happened
Cristiano Ronaldo has announced his retirement from international football. Since making his Portugal debut in 2003, the 41-year-old has scored 146 goals in 234 appearances, playing in six European Championships and six World Cups.

Ronaldo fell out with Portugal’s newly appointed coach Jorge Jesus after he was an unused substitute in a match in September. He claimed that Jesus “broke his word” in an explosive 1,966-word statement posted on Instagram. He was subsequently handed a €255 fine (£215) and a 30-day suspension by the national federation.

Who said what
It is time to “hand back the number seven shirt of our national team”, said Ronaldo in a video statement. He has received tributes from former teammates Bruno Fernandes, Neymar and Pepe.

Ronaldo was “more than just an outstanding athlete”, he was the “ultimate symbol of the spirit” of the team, said the Portuguese Football Federation (PFF).

What next?
Ronaldo will keep playing at club level, where he is earning a reported £400 million a year with Al-Nassr in Saudi Arabia. He requires 15 goals to reach a career tally of 1,000. The PFF confirmed that a “fitting tribute” would be paid to Ronaldo in the future.

A California startup has used artificial intelligence to create a virus that is reportedly capable of fighting off a bacterial infection. The method, if proven to be effective, could help people combat disease without worsening antibiotic resistance.

Researchers at Radical Numerics administered the AI bacteriophage – through a model called Omnii-1 – to a patient “suffering from a deadly bacterial infection” in the hope that the virus would “kill the microbes causing the infection”, said The New York Times. If successful, the process could “point to a new way to use AI in medicine”.

Phage therapy existed long before AI, although it can be time-consuming. Using AI instead “can lead to rapid, on-demand generation of phages that meet patient requirements, accelerating the timeline for treatment”, said The Independent.

“If it works, that’s incredible,” Michael Baym, a microbiologist at Harvard University, told the Times. “My impulse is to be skeptical.” Radical Numerics has not revealed the clinical outcomes of the patient who was given the AI virus and the study has yet to be peer reviewed. Eric Nguyen, the CEO of Radical Numerics, told the Times the company aimed to “protect patient confidentiality and maintain the trust” of clinical partners, but that it intended to publish the results in the future.

Widespread phage therapy could help combat antibiotic resistance. Phages “do not infect human cells, and phage therapy is generally considered safe”, according to Radical Numerics. “Unlike broad-spectrum antibiotics, phages can target particular bacteria with remarkable specificity.”