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A round up of the stories that may have snuck past you in this week’s edition of science digest…

Sharks aren’t so scary

Sharks have a very frightening role in our cultural history, but Australians don’t find them as frightening as jellyfish or drowning, according to new research from the University of South Australia.

The study, published in the Journal of Environmental Studies and Sciences, surveyed 400 participants about their fears of being in the ocean. 

They found that drowning, other animals such as jellyfish, crabs, and stingrays, and deep water were the things that frightened people the most. Sharks came in at fourth on the list.

“We’ve all seen Jaws and read the sensationalised headlines about shark “attacks” – given sharks’ representation in the mass media, it would be easy to assume that everyone’s biggest fear is an encounter with a shark,” says Brianna Le Busque, a lecturer in psychology at UniSA.

“In reality, our study found more people fear drowning than sharks when it comes to swimming in the ocean.

“It’s promising to see that people’s fears are actually aligned with the statistical chance of these threats, given many more people drown per year compared to fatal shark interactions.”

Le Busque adds that this is positive news for shark conservation, as it means there’s a change in people’s perceptions about sharks.

“We know that people are less likely to support conservation initiatives and more likely to support potentially harmful mitigation strategies if they fear sharks. To support shark conservation, we need to reduce the perception of risk sharks pose to better reflect reality.”

Exercise outdoors for better motivation

Exercising in nature may lead to positive motivation, according to research published in Frontiers in Sports and Active Living.

The researchers surveyed 750 New Zealanders during the 2020 April lockdown, and found that those who exercised in natural environments had higher levels of motivation to exercise – and thus better overall wellbeing – than those who exercised indoors.

Exercisers in general had better wellbeing than non-exercisers, so this is no excuse to take a day off when it’s raining.

The research was carried out at the University of Otago, in NZ’s South Island.

Effects of dingoes visible from space

A study from the University of New South Wales has used satellite imagery to show the effect of dingoes on the natural environment.

The research, published in Landscape Ecology, looks at satellite imagery from either side of the Dingo Fence, which stretches 5,600km from Queensland to the Great Australian Bight.

Focussing on the Strzelecki Desert, the researchers examined 32 years’ worth of images, going back to 1988.

Ymhm dingo fence
Australia’s dingo fence, which stretches 5614km, is one of the longest structures in the world. Credit: Mike Letnic

The research found that vegetation was poorer on the dingo-less side of the fence.

“Dingoes indirectly affect vegetation by controlling numbers of kangaroos and small mammals,” says Mike Letnic, senior author on the study. 

“When dingoes are removed, kangaroo numbers increase, which can lead to overgrazing. This has follow-on effects to the entire ecosystem.”

“The Australian dingo fence – which is a sharp divide between dingo and non-dingo areas – is a rare opportunity to observe the indirect role of an apex predator.”

Ymhm satellite dingoes
A satellite image from 1990 showing the different vegetation across the dingo fence. Credit: Adrian Fisher USGS/JRSRP

While land use and rainfall patterns have also had an effect on vegetation either side of the fence, this research shows that dingoes played a central role in the differing environments.

“There were clear differences in landscape on either side of the dingo fence,” says Adrian Fisher, lead author on the study. “Dingoes may not be the whole explanation, but they are a key part of it.”

Frost crystals take a leap

A research team in the US has managed to make crystals jump off a sheet of frost, using electric charges.

The research, published in the journal ACS Nano, describes how positive and negative ions separate in water as it freezes. Those ions move at different speeds across the crystal when prompted to move – by something like a temperature change or an electric charge. This means the top of a frost crystal can become negatively charged, while the bottom becomes positively charged.

Ymhm jumping frost
Frost breaks off and “jumps” upward due to an electrostatic charge. Credit: Virginia Tech

The team suspended a water-soaked piece of paper over a sheet of frost. They found that the negative tops of the frost crystals were attracted to the positive ions in the water, making the crystals jump from the sheet to the paper. They captured photographs of the moving frost particles, and even a video – available for view on the lab’s home page.

This effect can hopefully be applied to much larger pieces of frost.

“If we can amplify this electrostatic de-icing effect, such that entire sheets of ice or frost are instantly ripped away from their surface, it could be a game-changer for the aircraft and HVAC industries,” says Jonathan Boryeko, lead researcher on the study.

Mushrooms for better health

The health and nutrition benefits of mushrooms are well known, but it’s always nice to have more evidence. A study published in Food Chemistry has found that button and oyster mushrooms could boost antioxidant levels and help to control blood sugar.

The researchers fortified wheat noodles with powders made from the caps or stems of both mushroom types, then simulated the digestion process in the lab to see how they fared.

They found that the fibre from both types of mushrooms could help to slow the release of starches and sugars from the noodles. They also found that the button mushrooms in particular would be useful for producing antioxidants.

The researchers hope to test this outcome next in humans.

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