Nature Bytes

Nature Bytes

Turning garden waste into fuel

As garden owners are fond of keeping their gardens clean, they often trim the overgrowth and remove fallen leaves, twigs and other biomass. The garden waste that is generated after cleaning is usually burnt or disposed off. What if all that waste needn't be wasted but can instead be put to good use, by converting it into fuel for cooking? Scientists from Indian Institute of Technology, Bombay have been exploring ways to do exactly this. In their new study, the scientists demonstrated an efficient way to convert garden waste into fuel pellets that could be used for cooking.

For the study, various parameters like moisture content, milling size and die size of the pellets that were formed were probed for optimal performance, using regression models. Their study showed that an increase in the moisture content of the biomass affected the durability of the final product. It also revealed a biomass moisture content of around 6% and a die size of 15 mm were ideal for the pellets to perform efficiently.

The pellets were also probed under a scanning electron microscope to study the effect of moisture on the final product, which showed the pellet particles sticking closely together when the moisture content in the biomass was considerably low. If commercialised, the technology could be used as a suitable substitute for cooking gas and other fuels.

How to get a killer whale to say 'hello'

Have you ever wanted to talk to a killer whale? First, you should introduce yourself by saying 'hello'. You might be surprised by what the whale says back. In a paper published in the Proceedings of the Royal Society B recently, scientists report that a 16-year-old orca named Wikie was able to copy a variety of new sounds on command. The study joins a growing body of research illustrating the deep importance of social learning for killer whales.

"We wanted to study vocal imitation because it's a hallmark of human spoken language, which is in turn important for human cultural evolution," said José Zamorano-Abramson, the researcher who led the study. This study provides "gold-standard, controlled experimental evidence" that orcas can learn fresh sounds through imitation, said Luke Rendell, a cetacean and social learning researcher at the University of St Andrews University, UK, who was not involved in the work.

For their study, José trained Wikie's calf, Moana, to make five sounds outside of Wikie's natural repertoire. Then they instructed Wikie to copy each vocalisation, either by listening to Moana directly or through speakers. They also tested whether Wikie could emulate six human words or phrases. The researchers first asked human listeners to judge whether Wikie's calls matched the ones she was asked to parrot. Then they used an algorithm to evaluate her vocalisations. Both human and machine methods deemed Wikie successful at learning the novel sounds presented to her, including those uttered by humans.

What happens when you sedate a plant

A study published in Annals of Botany has shown that plants can be frozen in place with a range of anaesthetics. The research also highlights that plants are complex organisms. "Plants are not just robotic, stimulus-response devices," said Frantisek Baluska, a co-author of the study. "They're living organisms which have their own problems. In order to navigate this complex life, they must have some compass." Plants sometimes use that compass to deal with stress, competition or development. They take in information from their environment and produce their own anaesthetics.

The researchers trapped pea plants in glass chambers with ether, soaked roots of the plant and seedlings of garden cress in lidocaine and even measured the electrical activity of a Venus fly trap's cells. An hour or so later, the plants became unresponsive. The seedlings stayed dormant. And the Venus fly trap didn't react to a stimulus similar to a bug crawling across its maw. Its cells stopped firing. When the dope wore off, the plants returned to life.

Years of Living Dangerously

Years of Living Dangerously is a documentary series that focuses on global warming. The episodes explore the effects of rising sea levels, historic droughts and flooding, water scarcity, ocean acidification, deforestation and the rapidly increasing extinction rate of species. In addition, it also takes a look at the ways individuals, communities, companies and even governments can follow to address worldwide climate change, including solar and wind energy, and advancing battery technology.

Each episode in the series features celebrity hosts with a history of environmental activism and well-known journalists with a background in environmental reportage. They interview experts and ordinary people affected by, and seeking solutions to, the effects of global warming. To watch the documentary, visit


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