Anyway, let's get to the week's happenings!
Space strikes back! (Pre-emptively!)
Last week, I wrote about how we bombed the Moon. It is now being reported that on September 25, space attacked us!
A family in Ontario woke up to find that their car had been vandalized. The hood was smashed in, and there were rock fragments all around. They filed a police report and left it at that. But later, they heard about an exceptionally bright meteor that had been spotted over Ontario and put the facts together.
Unfortunately, they didn't get much rock out of it. A larger chunk could have paid for the repairs.
Fruit flies are the best
Two stories involving Drosophila this week.
The first is that mind control took one step closer to reality. Researchers took some fruit flies and labelled their brain cells so that they could read which ones were responsible for associating a particular smell with an electric shock. This is a pretty good feat in itself: they managed to find that only 12 neurons were responsible for this.
Then they gave different flies some chemicals that would activate brain cells. A tricky bit was in releasing those chemicals. You don't want them just floating everywhere, or else every neuron gets activated, so they made them light-sensitive. Now, instead of shocking the fly when the smell was present, they shone light on the proper cells. Amazingly, the chemical/light-treated flies learned to be scared of the smell in the same way that the shocked flies did.
I'm not sure how I feel about this. On the one hand, science fiction teaches us that mind control is bad. On the other hand, if I could learn all there is to know about physics just by injecting chemicals into my brain and shining some light inside my head, that would save me a lot of school work.
The second story is responsible for the funniest picture ever published in an esteemed science journal. I present it here for your amusement.
It was discovered that male fruit flies will mate with anything that is fly-shaped, regardless of species or gender, if the proper chemical cues identifying those characteristics are not there. Females, on the other hand, have no interest in males without the proper chemicals. (A cynic might apply this to human behaviour by replacing "the proper chemicals" with "wads of cash.")
(If you follow the link above, you will see a picture in which they use green fluorescent protein, the creation of which won the Nobel Prize last year.)
Progress in treating Parkinson's
For all the talk about animal discoveries, it's sometimes easy to forget how much these studies affect people.
Parkinson's disease is caused when the brain cells responsible for producing dopamine don't function properly. Dopamine is a neurotransmitter, meaning that it helps to send signals between nerve cells (and brain cells). When the body lacks enough dopamine, signals either can't go through or don't go through properly. This leads to muscle tremors, difficulty in moving, and eventually paralysis. There are all sorts of nasty side effects: if you don't blink enough, then your eyes get sores, for instance.
The standard treatment is to give doses of L-DOPA, which the brain converts into dopamine. The problem is that it gets converted everywhere in the body, leading to dopamine excesses, which in turn cause a loss of fine motor control, and eventually cause liver failure (among other problems). Other experimental treatments are more radical, including wire implants in the brain to stimulate the appropriate brain cells.
Parkinson's is a difficult thing to diagnose, in part because there may be many different ways it can occur. Several different mechanisms have been proposed, and from the evidence, it looks like different people may get the disease for different reasons. That makes finding a cure a difficult prospect.
But there is hope. Stéphane Palfi and co-workers gave some monkeys the equivalent of advanced Parkinson's by injecting them with poisons that disabled their dopamine-producing brain cells. Then, they injected three genes responsible for producing dopamine into the monkeys' brains. The monkeys recovered, and don't appear to show any side-effects.
This is not a cure, exactly. Whatever is affecting the original cells is still there. But by having a different path to produce dopamine, the problems associated with the disease disappear. The down side is that you can't control just how much dopamine is being produced in this way, but it looks like the genes given to the monkeys are regulating themselves.
They're currently starting human trials on this. I don't know if the gene therapy needs to be repeated over time, or if it's a one time thing, but this is good news for a lot of people.
Ocean observations
A few years ago, I went to a high performance computing conference at which the guest speaker spoke about a project called NEPTUNE. He'd just come back from a trip to place sensors all over the ocean floor near Vancouver Island, and had interesting things to say. Their technical stuff was amazing: a big power line into which new sensors could be plugged as they were developed, live data acquisition, and a variety of instruments that would give unprecedented measurements of the ocean floor, both in terms of geology and biology. Check out some of the images.
I was reminded this week of NEPTUNE by news that the USA's stimulus package included $100 million for the Ocean Observatories Initiative. Good stuff! They're planning on doing around the world what NEPTUNE is doing off Vancouver Island.
Bending light
We've all heard about the technology to make invisibility a reality, right? You may recall breathless news reports from last year which invoked the name of Harry Potter and an invisibility cloak. Of course, those were massively overblown--the materials used were only created on a small scale. But it is still interesting.
There's a nice little writeup on metamaterials here, if you missed the hype at the time, and a less accurate but easier to read one here. The exciting part, for physics people, is the phrase " in 2000... a metamaterial was demonstrated to have a permittivity and permeability both less than zero." For non-physicists, that means you can do things with light that don't normally happen, like bend it around objects in weird ways, or make magnetic and electric fields go backwards to what you'd normally expect.
The same technology has been used to capture microwave light and focus it on a point to create heat. Big deal, you say, I used to do that with ants and a magnifying glass all the time. True enough, but what's special here is that essentially all the sunlight being captured is turned to heat: with your magnifying glass, you were getting at best 30%. This has big implications for some types of solar energy.
The authors of the article call their discovery a "black hole." Obviously, this isn't a real black hole. What they mean is that they've developed a device from which light at certain frequencies can't escape because of the electromagnetic properties of the material used. For a real black hole, no light can escape because of gravity. Completely different, and just titled like that to catch attention.
Ptransitional pterodactyl
More dinosaur news from China: the discovery of Darwinopterus modular. This is a pterosaur from the Middle Jurassic (call it 165 million years ago) which seems to bridge the gap between primitive pterosaurs and the later pterodactyloids in an interesting way.
The article itself has a pretty chart showing the relationships between the various pterosaurs, and if you love these things as much as I do, you will want to browse The Pterosaur Database. Open the pretty chart, if you will. I'm going to refer to it soon.
Darwinopterus is interesting to evolutionary biologists because its existence supports an idea called modular evolution. We all know how evolution works: creatures more adapted to their environment are more likely to reproduce, so the genes that make them more adapted get passed on. The questions that biologists ask relate to how fast evolution occurs. In particular, is it constant through time, with large external pressures and extinction events only contributing by wiping out the weak, or does evolution happen mostly during these events, and very little during stable periods? (Darwin, after whom this dinosaur is named, favoured the idea that most evolution happened quickly, but also knew that it could occur slowly and steadily as well. This is because he was a very great man who made careful observations and thought hard.)
Modular evolution proposes that creatures evolve in modules. One piece gets adapted. Then another. Then another. I don't know what the name for the other kind is, where everything develops simultaneously.
Darwinopterus has the skull (and some other features) of a late pterodactyloid, but the tail of an early pterosaur. If you leave out the skull, then it looks exactly like a reptile in the red group in that pretty chart. If you leave out the tail, it looks exactly like it should be in the blue group. (These are marked by D1 and D2 on the left side of the diagram. The creature itself fits into the purple bracket, number 7).
So it looks like the modular evolution theory holds in this case. The transition from early flying reptiles to late flying reptiles happened one characteristic at a time, probably brought about by abrupt changes in prey or climate. (When I say "abrupt," I mean "over only a couple million years.") It's probably not good to conclude that all evolution occurs this way, though, which is what some of the newspaper articles are implying.
Pterosaurs: they're like Tyrannosaurs in F-14s.
High pressure region in the heliopause, and first direct detection of H and O in the ISM
Titles like that are awesome. They sound sciency.
At the edge of our solar system, well beyond Pluto, there is a divider. At this divider, the particles spit off by the Sun (called the solar wind) hit the cold bubble of interstellar space. Our solar system is in a bubble, of sorts. Space is full of gas (the interstellar medium, or ISM), and the solar wind is pushing this gas away. But it can only push so far, and the region where particles from the Sun are stopped is called the heliopause. It's not spherical, but no one's really sure why. In fact, no one's sure about much with regards to this region.
The Interstellar Boundary Explorer (IBEX) was built to study the edges of our solar system. It just returned its first results, and they are strange indeed. It has found a ribbon of dense material in the heliopause. They're attributing this to magnetic fields in the interstellar medium, which means all sorts of exciting new science is there to be done. We know almost nothing about how the ISM works, and this is a great start. (Did you know we don't even know if our galaxy has two or four arms? Weird, huh? We know tons of stuff about distant galaxies, but don't even know what our own looks like.)
IBEX is neat because it uses a special method of observation. Normal telescopes pick up light of various frequencies. However, the ISM consists mostly of neutral atoms, which don't emit light, at least not light that we can see. So IBEX was built to capture energetic neutral atoms, or ENAs. When our solar wind comes into contact with the ISM, some of the slow ISM atoms get accelerated, and some of these get shot toward the centre of the Solar System, where we are.
I'm curious, now. Voyager I is out in this ribbon. Where did the Pioneer craft go? Could something like this, an unexpectedly large number of incoming energetic neutral particles, be the cause of the Pioneer anomaly? They meet the criteria: they would slow a spacecraft's acceleration outwards and are otherwise invisible. It would be interesting to compare IBEX's sky map with the trajectories of the spacecraft affected to see if there is a link (of course, taking into account the effect of the Sun's shielding).
Fractional Hall Effect in graphene
I'm just going to link to this and let you read it. Fractional electron charges? The world gets ever weirder.
That's all for this week! I'm going to make myself an origami pterosaur! Coming during the week: another complaint about Dan Brown's latest book (hint--don't read it if you value your sanity), and a few simple science projects that someone should do.
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