What happened
The Duke of Sussex spent just under an hour with the King yesterday evening at Clarence House, marking their first face-to-face meeting in 19 months. Harry, who has been in Britain on a four-day visit linked to his charitable work, travelled to central London after engagements in Nottingham and at Imperial College’s Centre for Blast Injury Studies. He is due to return to California today.

Who said what
After the meeting Harry told a well-wisher at an Invictus Games reception that the King was “great, thank you”.

“The reunion, albeit brief, will be seen as a turning point in the pair’s relationship,” said Victoria Ward in The Telegraph. But while the meeting is viewed as a possible step towards easing tensions between Harry and his father, the duke remains estranged from his brother, the Prince of Wales, and there are currently “no signs” of them meeting during Harry’s visit, said the BBC’s royal correspondent ​​Sean Coughlan.

What next?
Prince Harry continues to insist that it is not safe to bring his wife Meghan and their children to the UK, leaving uncertainty over when the family might next gather together.

What happened
A blood test that could identify Alzheimer’s is being trialled on UK patients with suspected dementia. A team led by University College London (UCL) will recruit 1,100 people via memory clinics to see how well the test, which measures the protein p-tau217, improves early diagnosis. Analysts believe that the test can inform about 80% of people experiencing cognitive decline whether they are likely to have Alzheimer’s.

Who said what
The trial could be a step forward in “revolutionising” diagnosis, said Jonathan Schott, professor at UCL and chief medical officer at Alzheimer’s Research UK. Identifying Alzheimer’s early and accurately “will become even more critical as a new generation of treatments emerges”.

Alzheimer’s is linked to “the build-up of two key proteins” – amyloid and tau – in the brain, said Sky News. P-tau217 is “considered a promising biomarker” that shows the presence of both.

What next?
The study will recruit people from diverse geographic, ethnic and economic backgrounds, alongside those living with other health conditions. Twenty NHS trusts are expected to take part and experts hope to have some answers within three years.

Beneath Antarctica’s vast expanse of ice sit hundreds of canyons, some up to tens of thousands of feet deep. These complex formations under a seemingly barren landscape play a significant role in global climate change and ocean circulation – and studying them could lead to better climate models and predictions.

Scientists have mapped 332 underwater canyons in Antarctica, according to a research article published in the journal Marine Geology. Some of these are deeper than 4,000 meters (over 13,000 feet). Scientists posit that the canyons “may have a more significant impact than previously thought on ocean circulation, ice-shelf thinning and global climate change, especially in vulnerable areas such as the Amundsen Sea and parts of East Antarctica”, said David Amblàs, part of the Consolidated Research Group on Marine Geosciences at the University of Barcelona and one of the authors of the article.

Submarine canyons are “vitally important to ecological, oceanographic and geological processes worldwide”, said Discover magazine. The canyons “facilitate water exchange between the deep ocean and the continental shelf, allowing cold, dense water formed near ice shelves to flow into the deep ocean and form what is known as Antarctic Bottom Water”, said a University of Barcelona statement. They also do the reverse, where they transport “warmer ocean waters from the sea towards the coastline”, which helps “maintain and stabilise Antarctica’s interior glaciers”, said Discover.

Scientists have identified approximately 10,000 submarine canyons globally, but most remain unexplored, particularly those in polar regions. “Mapping the seafloor and its influence on the movement of water is necessary to build accurate ocean circulation models,” said The Guardian.