Cristy Burne

Feeling fuzzy? Go brush! That sweater-mouth feeling is plaque, a layer of soft white gunk coating your teeth.

And don’t forget floss, especially since today is Flossing Day. (Happy Flossing Day everyone!) And guess what? You can even use the same piece of floss as last time.

Don’t believe me? Ask your dentist. I did, for CSIRO’s Double Helix magazine….

Flossed in translation

If you look at unbrushed teeth using a microscope, you’ll see hungry colonies of bacteria munching sugary leftovers from between your teeth. These bacteria release acids that dissolve the protective enamel on the outside of your teeth, and cause cavities.

“Brushing your teeth removes these bacteria, so they can’t sit on the surface of your tooth for too long,” explains dentist Dr Peter Klages. “But if you’re snacking throughout the day, the bacteria have a constant supply of sugar to work with, so you’re increasing your decay rate.”

Peter says it’s fine to brush right after a sugary snack, like dried fruit or lollies, but wait half an hour before brushing after an acidic drink, like juice or soda. This gives your saliva a chance to neutralise the acids and protect your enamel.

And what about re-using floss? Well, you reuse your toothbrush all the time, so…

“There’s no harm in reusing floss, provided it’s still intact enough to clean between your teeth,” says dentist Dr Peter Klages. “Flossing once a day maintains healthy gums, and helps avoid decay where the brush can’t reach.”

Just add water

Lost in the jungle without a toothbrush? No excuse.

“It doesn’t matter what you use, as long as you’re cleaning thoroughly,” says Peter. “Some cultures use cloth, others use a stick that has been feathered at the end.”

It’s best to brush twice a day: after breakfast and before bed. Peter also recommends drinking water after a meal, to wash away food particles and acid.

Mouth party

Dark, warm, moist and stuffed with food, your mouth is home to more than 400 species of bacteria, but not all of them cause decay. The main culprit is Streptococcus mutans, a bacterium that combines with proteins in your saliva to grow into plaque.

The new drill

Has your dentist spotted signs of early decay? A University of Sydney study suggests early decay can actually be reversed, with up to 50 per cent of fillings avoided if you:

1. Ask your dentist to coat the trouble spot with fluoride varnish
2. Clean the spot super-well every time you brush
3. Cut back on sugary snacks and drinks
4. Visit your dentist regularly

Peter says a two-minute brush is the minimum: “Brushing faster isn’t going to clean any better…You have to take time to get into those all the nooks and crannies, to clean really well.”

Happy International Veterinary Medicine Day! My best friend is a vet, and she spends her days looking after our pets. One of the things she does is inject microchips, to help us identify and find lost pets.

In Australia today, most dogs and cats carry a tiny microchip – about the size of a grain of rice – under the skin between their shoulder blades. Your pet can’t feel its chip, but this mini device helps many furry friends to find their way home.

Lost and found: family pet

Vets like my friend use a special needle to inject a microchip under your pet’s skin. This is quick and only stings for a second, much like a vaccination. Once injected, the chip stays with your pet for life.

Each chip is coded with a 15-digit identification (ID) number. This number is listed in a database, matched with your pet’s name, address and owner details.

Your pet’s microchip is passive, which means for the most part, it does nothing.

“Basically it’s a glass tube with a copper coil inside it. It has no battery or anything like that,” says Bruce Knight, of Micro Products Australia.

But if you lose your pet, or find a lost pet, a vet can scan its microchip to reveal its ID number.

“Just like scanning groceries at the supermarket,” says Bruce.

Radio frequency identification: Power up!

To communicate your pet’s ID number, the chip needs a source of energy. Providing this energy is the job of a microchip scanner.

Microchip scanners broadcast a low frequency radio wave of 135 kHz, or 135,000 vibrations per second. This wave is invisible, a very slow version of the same radio waves you tune into when you listen to music on the radio.

“All pet microchips must operate on that frequency,” says Bruce. “No matter where you go in the world, they will have a scanner that can read your microchip.”

When this low frequency radio wave bumps into your pet’s microchip, it sends a tiny electrical current whirling around the chip’s copper coil. Like a key winds a clock, the current provides just enough energy to power the microchip.

Once powered, the microchip can emit its own unique radio wave. The scanner captures this radio wave and decodes it, displaying your pet’s ID on its screen. The scanner must be held close to the microchip, because the radio wave has so little energy.

This use of radio waves to send coded information through the air is called radio frequency identification (RFID).

Did you know? Some microchips include a thermometer: when you scan the chip, it sends back your pet’s temperature as well as their ID.

From libraries to polar bears

RFID chips are everywhere: they’re used by libraries to manage books, shops to prevent shoplifting, and farmers to track the farm their animals grew up on, and the vaccinations they’ve had. Researchers use RFID chips to track rhinos in Namibia and polar bears in the Arctic.

You’ll also find RFID used in automatic toll booths, car immobilisers, electronic passports, smart travel cards and contactless card payments.

I originally wrote this article for CSIRO’s Double Helix magazine. Happy International Veterinary Medicine Day!

How cool are sloths? It’s time to celebrate! On this International Sloth Day, let’s celebrate sleep! Sloths in the wild sleep around 10 hours a day. Two hours is enough for a fruit fly, but cats sleep need 15 hours a day, cows sleep just four hours, and humans?

Well…how long do you need to sleep?

Stages of sleep

When you’re asleep, your brain produces characteristic brain waves. We graph these brain waves by measuring electrical activity inside your head.

We know that humans sleep in repeating cycles, each around 90 minutes long. Each sleep cycle includes different types of sleep:

• Transition: You are drifting between being asleep and awake. You can be easily woken.
• Slow-wave sleep (SWS or non-REM): You are deeply asleep. Your eyes don’t move. Your body temperature drops.
• Rapid Eye Movement (REM) sleep: You’re still asleep, but your eyes are darting around, your heart is pumping fast, your brain is working hard…

If you sleep for ten hours a night, you’ll spend around two hours in REM sleep. We think REM sleep helps you learn and create memories. Most dreams happen during this time.

Dragon dreams

Gilles Laurent studied the brain waves of Australian bearded dragons. He found their sleep also cycled through REM and non-REM sleep, but much faster than humans: one cycle every 80 seconds, around 350 times a night.

This shared pattern of REM and non-REM sleep means the way we sleep and form memories may have evolved more than 300 million years’ ago.

“It suggests that these features existed also in dinosaurs, which are the reptilian ancestors of birds,” Gilles says.

Does this mean lizards dream?

“It depends a lot on how one defines dreaming,” says Gilles. “If one defines dreaming simply as off-line replay of previous activity…then I’d venture to say that pet lizards do dream.”

Animalzzzz

All animals need to sleep, but there are different ways to catch zeds.

Some animals—like dolphins and ducks—sleep with only half their brain, so the other half can stay alert and awake.

Many large herbivores—like elephants, cows and horses—can sleep standing up, but must lie down for REM sleep.

Newborn kittens and puppies only have REM sleep, suggesting this type of sleep is important to early brain development. As they get older, they have less REM sleep.

The platypus enjoys more REM sleep than any other mammal. Platypus have been seen ‘swimming’ or munching imaginary food while they’re asleep.

Even insects sleep. Fire ant workers nap for about a minute, 250 times a day; their fire ant queens sleep for six minutes, 90 times a day.

Sleep your way to success

Getting enough sleep is linked to improved creativity, concentration and memory, even in animals. Tired fruit flies, for example, make more mistakes and struggle to remember important things.

Sleeping can also help animals make healthier choices. Mice who don’t get enough REM sleep are more likely to eat fatty and sugary foods.

Are you human? Aged 6–12 years? Aim for 9–12 hours of sleep every day.

Help! My hamster’s dead!

Limp and floppy? Don’t panic. Your beloved pet may simply be hibernating.

Hibernating animals seem to ‘sleep’ away the winter, but we can tell from their brain waves that they’re still awake. When an animal ‘wakes’ from hibernation, it hasn’t actually slept, so it needs lots of proper naps to recover. Squirrels, frogs, mice, bats and even hamsters hibernate.

This article originally appeared in CSIRO’s Double Helix magazine.

Ever seen 10 million bats? Would you like to? How amazing would it be to see the fruit bat migration in Zambia’s Kasanka National Park?!!?

Five to ten million straw-coloured fruit bats migrate every year through Zambia’s Kasanka National Park.

When the bats feast on fruits in the national park’s swamp forest, they’re hard to miss.

But after they leave, they can fly on journeys of thousands of kilometres. Tracking them has never been easier, thanks to GPS.

Dr Martin Wikelski, director of the Max Planck Institute for Ornithology, tags the bats with mini high-resolution global positioning systems (GPS).

“The [tracking] devices can be downloaded from afar,” Martin says. “Also, they record 3D-acceleration, so we can reconstruct the behaviour of the bats while on the move.”

We can use this tracking data to answer many batty questions: How do bats interact with humans and wildlife? What foods do they eat? How do bats help the environment with services like spreading seeds?

We can also combine this bat data with data from other tracked species and from environmental sensors to help understand what’s happening in the broader ecosystem.

A version of this article first appeared in CSIRO’s Double Helix magazine… Bats do give me a bit of the creeps, but I also think they’re beautiful. Anyone keen to head to Zambia for the next migration? Happy International Bat Day!