Now on Nature Network

In hope of bringing more readers to this blog, I decided to move it to Nature Network. From now on my posts will be published here. Follow me!

Of mice and parachutes

This Guardian piece, tucked away in the Education section, has such an eye-catching title that I decided I was going to blog about it even before I read the article. Seriously, compliments to the editor (or the author?): “Why dead mice need parachutes in the forest”. The facts reported in the piece are even funnier than the title might suggest.

Why would dead mice need parachutes, you may ask? The answer is, possibly, odder than the question: to deliver poison to tree snakes. Guam is an island in the Pacific Ocean, an unincorporated territory of the United States, which is infested by brown tree snakes (Boiga irregularis). They are thought to have been a stowaway on a US military cargo back in the days of World War II. Having no natural predators on Guam, they quickly became numerous and troublesome. They prey on domesticated birds, they occasionally cause power outages by climbing on transmission wires, and they even bite small children mildly affecting them with their venom. Besides being a nuisance to humans, they have also eaten to near extinction some native birds and lizards posing a serious ecological threat to the island.

The solution to this problem passes for reducing the tree snake population, and this is how the mice and their parachutes get into this story. The principle is simple: snakes that eat poisoned mice die. But you can't simply drop poisoned mice on Guam rain forests because other species, such as the coconut crab (a protected species), can become victims of this non-targeted approach to the problem. The solution? Parachutes. If you parachute the mice from an aircraft, they get entangled in the forest canopy where only the tree snakes can reach them!

The funniest thing is that this is not even what the Guardian article and the scientific paper it refers to are about. The key issue of the scientific study is the parachute itself.  About 10 years ago people tried plastic and cornstarch parachutes but the former take long to degrade and the latter dissolve too quickly in the rain dropping the mice to the ground. It is important to test different materials and types of parachute to make sure the mice get entangled in the forest canopy for long enough for the snakes to eat them, but do not pose an environmental problem. This is what scientists did.

Scientists attached various parachute-like objects – the list included paper plates, paper cups and paper streamers, amongst others – to dead mice and then thrown them from a US Navy helicopter into the forest. They also radio-equipped the rodents to track their fall. The results of the study indicate (you'll be glad to know) that all of the easily degradable materials tested work well. However, certain parachutes, such as the paper cups and paper plates, are not practical because they need to be secured to the dead mice with threads, which is a time-consuming process. The best method appears to be attaching paper streamers to cardboard which is then glued to one of the mouse's rear legs.

I know this is a serious and environmentally conscious scientific study. Yet, I cannot help laughing every time I picture the face of that US Navy pilot looking at the crazy people gluing stuff to dead mice before throwing them out of his chopper: “WTF!?”

photo: The Kids Window

Yeah right, as if space had weather

Well, actually, it does. Space weather was in fact what was keeping me busy until yesterday as I was invited to co-write an article about it. It is an interesting topic, worth blogging about, so if you are curious and would like to know more about the Sun and its influence on Earth, read on.

You've probably heard about Auroras or Northern Lights, or are even lucky enough to have seen one of these events. They are proof positive of the existence of some sort of weather in space. The term “space weather” refers to changes in the near-Earth space environment which are driven by the Sun. On a calm day, only a breeze of radiation and energetic particles – the solar wind – flows from our star. Sometimes particles from this wind stream into the Earth and interact with the gas in the planet's atmosphere. These interactions release particles of light causing Auroras.

photo: Wikimedia Commons

But not all days are calm and the Northern Lights are by far the least threatening effect of space weather. Trouble starts when our very active star decides to rebel and begins to emit large amounts of energy, not to mention electrically charged material into space. That's when you get the space weather equivalent of hurricanes.

The Sun is made out of a material called plasma. Plasma is the fourth state of matter: a solid can be heated up to become liquid, a steaming liquid becomes a gas, and a hot enough gas transforms into plasma. This happens because the atoms that form the gas are separated into their constituents, electrons and nuclei. It is of this, electrically charged, material that the Sun is composed.

In the solar interior, plasma is in constant motion. If you recall your physics lessons from high school you may remember that moving electric charges generate magnetic fields. In fact, the Sun is a ball of plasma with tangled magnetic field lines breaching through its surface. One of the interesting things about magnetic fields is that they can store a lot of energy. Every now and then the tangled lines of the magnetic field break and the energy they store bursts into space. These explosions are what solar physicists call “solar flares” – the storms of space weather.

It gets worse. Sometimes the magnetic field lines break so violently that they drag along some of the solar plasma. In this case, a coronal mass ejection (CME), the equivalent of a hurricane, occurs. CMEs cause the most damage when they are directed towards the Earth. When they hit, the electrically charged material and energetic particles of the solar wind and solar plasma surge into the Earth's atmosphere and surface. While this can cause brighter auroras, the more beautiful Northern Lights come with a price. CMEs can be harmful to astronauts and even airline crews and passengers. They can also affect satellites, interfere with communications and cause power blackouts.

Fortunately, most days are calm when it comes to space weather. Terrestrial storms and hurricanes are much more likely to cause damage than solar flares and CMEs. But the weather can always affect you. Even if it's in space.

How would you dance your PhD?

Work is keeping me busier than usual this week so this will be a brief post. I've decided to keep with the dance theme to let you know about an incredibly original idea I read about today. I've seen science being communicated in the form of text, diagrams, video and photography but this is a first. Dance your PhD is a contest that aims to get anyone with a science-related PhD, or studying to get one, to explain what their thesis is about through dance. (It definitely got me thinking about how I could dance a thesis on “Variability of Black-hole Accretion Discs: a theoretical study”!) The initiative is sponsored by Science and there's even a money prize for the contestants who best describe the scientific content of their PhDs in dance form, while putting on a creative and artistic show. Unfortunately it is too late to take part in the 2010 competition but there's always next year. In the mean time, think about it: how would you dance your PhD?

Hey babe, check out my dance moves

Picture the stereotypical scientist: male, shy, lacking social skills, single and, most likely, a disaster on the dancefloor. But here is an example of how science can be used to improve one's social life: research your way into impressing potential partners through dancing.

It takes no more than one night out clubbing to see that some men look hotter than others when they dance. But what exactly are the lousy dancers doing wrong? What are the key moves that work to increase your sex appeal? According to a carefully conducted scientific experiment at Northumbria University, where 3D avatars of male volunteers dancing were shown to straight women who evaluated their performance, this is bad:

video: Northumbria University

Plodding in a circle? No. Moving your arms and legs while keeping the rest of your body still? Forget it. Head-banging doesn't work either. Women don't seem to find men with repetitive dance moves attractive. Instead, they prefer movements showing variability and creativity which supposedly signal that the man is energetic, strong and healthy. According to the leader of the study, Nick Neave, the “brilliant dancers” are those that have different parts of the body “doing ever so slightly different things in time to the music”. Varied movements of the head, neck and torso appear to be key. So, men, all you have to do is mix up your moves and make sure your upper body is not still. The video below shows how it's done.

video: Northumbria University

Call me picky but I wasn't that turned on by that either...