We’re 40 years into the AIDS pandemic, and even with massive public health campaigns, still, 1 ½ million become infected with HIV each year; about half that number die of its ravages. And a study just out shows that this well-understood virus can still take on more worrying forms as a new variant has been uncovered. Although the total number of cases involved is small, and the new variant is as treatable as earlier strains, the finding underlines that viruses can become more infectious and more virulent.

Back in October 2020, before we had effective vaccines, 36 plucky volunteers agreed to be deliberately infected with SARS-CoV-2 in order to better understand the infection process and outcomes in what’s known as a human “challenge” trial. Dr. Chris Chiu from Imperial College reveals what they’ve learned now the results of the study are in. We’ll hear about a new plastic that’s stronger than steel and as many gardeners have long suspected, – spring-flowering has over many years been occurring earlier and earlier, at least according to a new UK study. We discuss the implications for the ecosystem.

Imagine spending six months of every year living in total shade. That’s what life is like for residents of the Norwegian town of Rjukan, set so low in a valley that they see no direct sunshine at all from October to March. Marnie Chesterton heads there to hear about an ingenious solution: giant mirrors that beam rays down into the town square, where locals gather to feel the reflected heat. The man behind the project was motivated by a need for winter sun – but how much difference does it really make to our health and happiness? That’s the question posed by this week’s Crowdscience listener Michael, who has noticed living in the rainy Australian city of Melbourne is taking its toll. Many pensioners claim sunshine relieves achiness as well as conditions like arthritis but one of the biggest scientific studies found temperature actually has no impact on reported pain levels, while factors like air pressure and humidity may play a role. When it comes to our mood, it seems that spending time outside is more important than feeling the heat and the optimum temperature for wellbeing is around cool 19 degrees centigrade, while excessive warm weather has been linked to an increase in violence and crime.

(Image: 3d illustration of HIV virus. Credit: Artem Egorov via Getty Images)