This is the Global News Podcast from the BBC World Service.

I'm Alex Ritzen and at 13 hours GMT on Friday the 28th of June,

these are our main stories.

US Democrats debate whether to stick with Joe Biden after his

faltering performance in the election debate with Donald Trump, continuing

unrest in Kenya despite the government's shelving of controversial tax rises. The industry benefiting

from India's heat wave.

Also in this podcast, why conservationists want to make the horns of rhinos radioactive.

We significantly increase the chances of that horn being detected as it's moved across

international borders at airports,

border crossings, things like that.

And new balls please, how a different kind of tennis ball could change the game. It was not a rematch that anyone in America desperately

wanted to see but after the CNN presidential debate between Joe Biden and Donald Trump last night,

it is the Democrats who will be most worried.

The Biden campaign had been hoping the 81-year-old president would be able to put to bed questions about his age.

But he failed spectacularly while his rival came out swinging.

Our senior North America correspondent Gary Adonahohue reports from Atlanta.

For the first time in debate history, a former president arriving to debate a current president.

That current president aiming to be the oldest incumbent of the White House in US

history. Four years ago when these two men met it ended up in a slanging

match.

Dahl Trump, but even new rules didn't stop the insults from flying.

...