President Putin has put Russia's nuclear forces on special alert. But what does that mean? And what safeguards are built into Russia's command and control system? Pavel Podvig is a senior researcher at the United Nations Institute for Disarmament Research in Geneva.

Satellite images show a huge Russian military convoy stretching for more than 60-kilometres north of of Ukraine's capital, Kyiv. Fighting has intensified despite talks aimed at securing a ceasefire.Vitalii Rybak is a journalist in Ukraine

Tragedy struck a North Queensland beach community on Saturday afternoon after a teenage boy died from a box jellyfish sting. Dr Lisa Gershwin explains the danger of box jellyfish.

BBC World reporter joins Bryan to report the latest news from around the world.

Farmer's wife and masters student at Otago Polytechnic, Kathryn Wright is looking for young rural men between the ages of 16 and 30. She wants to survey the pressures and effects that rural living has on their mental health. Kathryn worries that rather than seeking help - young men on farms tend to suffer in silence.

Bryce Wilson is an Australian photojournalist in Ukraine and describes to Bryan what he has witnessed the past few days.

The fifth day of war brought fierce resistance by Ukrainian forces and armed civilians who thwarted at least one attempt by Russian troops to advance into Kharkiv, Ukraine's second largest city. CNN's Correspondent in Moscow, Vasco Cotovio shares the latest.

Olha Viazenko and her husband moved from Kiev to New Zealand four years ago. Her mother lives alone in Kiev and Olha has lost contact with her and is also worried for the plight of other family members across Ukraine.

Jill Dougherty is an expert on Russia and the former Soviet Union and spent 30 years at CNN. She's in Moscow and talks about how the invasion of Ukraine is being explained inside Russia.

St John is facing increased demand for its ambulance service. Dr Tony Smith joins us to talk more.