“Never put anything smaller than your elbow into your ear” is something we’ve been wisely cautioned against at some stage or another. But more of us are ignoring this advice.

We use in-the-ear-headphones to listen to music, car keys and hair pins to scratch that particularly unpleasant itch, and hearing aids to enable better communication.

Many of us also use disposable foam earplugs to protect from damaging noises in the workplace, or to block the noise of snoring partners, loud traffic outside bedroom windows, dogs barking and any other bothersome sounds that prevent a good night’s sleep.

Stem-cell research holds promise for the treatment of a broad range of diseases and conditions, from spinal cord injury to autism. But more work is needed to turn this research into safe and effective therapies.

This week, an Australian woman delivered a baby at the age of 62 after having in vitro fertilization (IVF) abroad.

Few women can naturally conceive a baby later in life without the help of IVF – and these are rarely first pregnancies. These women go through menopause later, and have lower risks of heart disease, osteoporosis and dementia.

But does that mean that it’s safe to start a family later in life? Are there other risks and complications associated with pregnancy and childbirth in your 50s and 60s – or even your 40s?

Whatever happened to energy crops? A decade ago, the UK authorities confidently expected farmers to devote swaths of land to growing the likes of short-rotation willow and poplar and perennial grasses. These were to help feed one of the UK’s promising new renewable power sources – biomass energy, which burns plant materials to produce heat and power.

There are two features of life on the African continent that are fundamentally deadly to socioeconomic development. These are lack of cleanliness and punctuality.

There is plenty of discussion on macro and micro economics and the big theories of economic development, but it seems the African worldview is a primary problem. It is opportune to discuss more fundamental inhibitors to economic development and growth. In my view this entails a fundamental change in how things get done.

Many of society’s energy challenges require gigawatts of power, but many more are small – and some are entirely microscopic. To drive a new generation of tiny micromachines that could deliver drugs or clean traces of pollution, physicists are increasingly looking to biology for inspiration.

In work published in the journal Science Advances, my co-authors and I present a simulation of a sort of tiny “windfarm” powered by the natural self-organization of bacteria. It’s a small step towards harnessing the energy potential of microorganisms.