What would happen if you put your hand in front of the beam at the Large Hadron Collider? Find out...
Wednesday, November 24, 2010
Saturday, November 20, 2010
Which badges would you get?
Go to the website and compile your list: Badge Directory
Here's my list:
1. "Talking Science"
3. "Arts and Crafts"
4. "I'm confident around an open flame"
5. “I may look like a scientist but I’m actually also a ninja”
6. “Will glady kick sexual harasser’s ass”
7. “Has frozen stuff just to see what happens” (LEVEL I,II,III)
8. “Inordinately fond of invertebrates”
9. “I know what a tadpole is”
10. “Science has forced me to seek medical attention”
11. “Statistical linear regression”
Want to take part in a cool, real scientific study? Of course you do. Check out the bodyLAB! This project explores the evolution of human body shapes and our ideas of attractiveness. Basically, they try to quantify the judgments and decisions that we make about the attractiveness of others. They are trying to understand how all the traits that make up a human body combine to influence attractiveness.
In September 2010 the first results were published in the Journal of Experimental Biology (perhaps I'll review it in a future post). But this paper isn't the end of the study, it is ongoing, with the "population" of bodies refreshed every month. Recently, they've also added a facial attractiveness test. So visit the site more than once.
Wednesday, November 17, 2010
MSNBC has put up some wonderful pictures on their Earth as Art 2010 page. As you can see, these pictures are gorgeous! Look at lots more at the link below.
In the pre-dawn hours on the mornings of November 17th and 18th take a trip outside and look up. It is the time of year for the Leonid meteor shower. This meteor shower is due to the Comet Temple/Tuttle. As the comet makes its way around the Sun it loses some of its material as a debris tail, and when that tail crosses Earth's path we see the debris streaking through our atmosphere. Because that debris is not always uniform between years you may see a light shower or an especially heavy one, its difficult to say.
The shower will be visible through the constellation Leo (hence the name). For all observers Leo is along the ecliptic plane. This year is expected to be good, with about 15-30 (average of 20) meteors per hour, and you don't even need a telescope to see the show.
So set your alarm a little early, grab a lawn chair and some hot coffee, and find a nice dark place with little obstruction to watch the sky.
Read more about the Leonids here, including some good information on how to locate the constellation Leo:
Sunday, November 14, 2010
Tripod is an Australian musical comedy act. They specialize in improv, parody, and satire. The group is composed of three members: Scod (Scott Edgar), Yon (Simon Hall) and Gatesy (Steven Gates). Here, Tripod performs on The Sideshow ABC-TV about the aftermath of climate change.
Our planet covered in ice from one pole to the other. Doesn't really seem possible does it? Well, a controversial hypothesis called Snowball Earth posits that our planet was indeed covered with a thick sheet of ice for a period of its history. This thick sheet of ice lasted for millions of years and may have occurred more than once. The most severe likely occurred around 750-580 million years ago.
When an entire planet is covered in ice it is bound to have effects. A new(ish) paper in Nature takes a look at one of these effects and its relationship to life. But let's step back for a second...
Nutrients are chemicals that an organism needs to survive and grow, usually because they are vital to various metabolic and other bodily processes. What do we know about the kinds of nutrients that life needs to survive? Well, we know that life needs water (its inorganic but still counts), and if we're talking about a big melting ice sheet then we can check that one off our list. What about organic molecules? Sure. After all, we are organic and need building blocks, if you will, to help us live and grow. These building blocks, or nutrients, come in the form of carbohydrates, fats, and proteins (or amino acids), as well as various vitamins. Certain chemical elements are also important. These include carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur, calcium, etc. Of course, what type of organism you are will expand or narrow this list and vary the concentrations of these various nutrients.
The Nature paper zeros in on phosphorous. In most modern marine aquatic systems you will find that phosphorous and bioavailable nitrogen are the limiting factors. Usually when we are talking about nutrient limitations we're talking not about one being completely gone from the system but, rather, an imbalance of the nutrients. In the case of nitrogen and phosphorous you should see a nitrogen to phosphorous ratio of 16:1. It is generally thought that phosphorous limits productivity on a geologic timescale, and so it is particularly interesting to scientists to find the concentrations of this chemical over time.
In the aftermath of Snowball Earth, these researchers have found that the oceans were rich in phosphorus. Now, how in the world do you go about measuring that one? Well, these scientists looked at the rocks and sediments on the sea floor - about 700 samples of iron-oxide-rich rocks. They tracked phosphorus concentrations by analyzing the composition of iron-rich chemical precipitates which accumulated on the sea floor and took up phosphorus from the seawater. This analysis showed a spike in marine phosphorus levels in the mid-Neoproterozoic (from ~750 to ~635 million years ago). We know that the ice sheet melted right? Then it stands to reason that there was quite a bit of erosion and weathering going on at that time. These processes could explain the high concentrations of phosphorus in the seawater.
Let's take it another step, and link together what we know. Life likes phosphorus, there was lots of phosphorous in the seawater, therefore we should see more life in the oceans. Makes sense. Keep going. More life in the oceans means there's more oxygen production via photosynthesis, the oxygen is released into the atmosphere, atmospheric oxygen is available for other organisms. OK, good. Let's keep going. Oxygen is another of those molecules that life needs/likes, more oxygen availability, more animals using it and multiplying, throw in a little mutation and subsequent evolution, and bang! the emergence of more complex life on Earth.
Alright, alright, I agree, that's a lot of steps. Steps that all start at a single there-was-lots-of-phosphorus point. On their side, there is evidence that links marine phosphorus concentrations and the levels of atmospheric oxygen. And the authors aren't saying that this is definitely what happened. They are simply saying there was more oceanic phosphorus at that time and that it could have paved the way for the evolution of complex organisms and their diversification.
On a purely let's-look-at-the-chemicals level, until now scientists believed that the conditions of an iron-rich ocean would lead to low phosphorus levels. The fact that these researchers found the opposite after the Snowball Earth events is quite significant. We're talking about the finding of a possible nutrient driver behind one of the big explosions of life. Pretty neat.
Here's the source:
Planavsky, Noah J., Olivier J. Rouxel, Andrey Bekker, Stefan V. Lalonde, Kurt O. Konhauser, Christopher T. Reinhard, and Timothy W. Lyons (2010) The evolution of the marine phosphate reservoir. Nature: 467(7319): 1088 (DOI: 10.1038/nature09485)
(image from geos.ed.ac.uk)
Saturday, November 13, 2010
Genus Conus LINNAEUS, 1758. Not really a taxa that many people give much though to, but cone shells (or cone snails) are ubber cool. There are about 500 extant species of Conus, that's the largest genus of marine invertebrates. These mollusks are found between latitude 40° North and the 40° South parallel. That means you can find them in tropical and subtropical oceans including the Indo-Pacific, Panamic, Caribbean, West African, South African, Peruvian, Patagonic, and Mediterranean Seas. You can find a few other species outside of this region but they tend to be localized in South Africa, Southern Australia, and Southern Japan. Cone snails live in the intertidal muds and sandflats, areas where the high and low tides alternate, but you can also find some offshore or in deep waters.
When picturing the structure of a cone shell, think of something like an underwater snail. They have a strong, muscular foot with a flat sole that is truncated or widely rounded at the front and pointed at the back. The foot can be striped or pimpled, but the coloring is really variable, not just due to genetics but environmental factors as well. On each side of the head they have an eye on a stalk, stalks that are wide at the bottom and narrow at the end. The mouth of this animal is very elastic and includes sharp and often hooked teeth, allowing the cone shell to swallow large prey. Being a cone shell, they are covered by a shell. This shell is spiral shaped and can have interesting patterns, and they are very desirable to shell collectors.
Most people, including me, find the cone snails' venom to be its most interesting feature. We're talking venom that is often fatal, or at the very least causes temporary paralysis, respiratory trouble, or swelling and inflammation (depending on the species). The composition of this venom varies depending on the species, the individual, or even between injections by the same individual. The active components are small, disulfide-rich peptides called conotoxins or conopeptides, and they cause paralysis in the victim. The specific paralytic components include alpha-, omega- and mu-conotoxins which all prevent neuronal communication, each targeting a different aspect of the process. Alpha-conotoxins target the nicotinic ligand gated channels, omega-conotoxins target the voltage-gated calcium channels, and the mu-conotoxins target the voltage-gated sodium channels. These toxins are particularly interesting to scientists, especially neurobiologists and medical researchers, because they can be used to identify specific ion channels.
To be effective the venom must be delivered from the cone shell to the prey. The cone shell itself is relatively slow and unable to swim, and yet it hunts other, faster marine organisms such as fish. The venom is synthesized in the epithelial cells of a long, convoluted venom gland and stored in the gland's lumen. When the cone snail zeros in on its prey it extends it's proboscis which is loaded with venom and tipped with a specialized radula tooth that functions as both a harpoon and hypodermic needle. The snail then shoots it (by a ballistic mechanism, we're talking around 400 miles per hour) into the prey to deliver the venom. It is known that the distal end of the venom gland dilates into an oval structure called the venom bulb and it has been suggested the this bulb functions in venom transport, perhaps like a peristaltic pump. If you look at other animals that use jet propulsion, like scallops and squid, you see that the closing of their valves requires a burst contraction of the adductor muscle. This muscle shows high levels of glycolytic enzymes as well as arginine kinase (a type of phosphagen kinase).
|Figure 1 showing the venom apparatus of cone snails.|
Also, Figure 1A is probably the best figure I've ever seen in a peer reviewed paper.
After lots of tables and graphs, some colorful and pretty and some not-so-much, they found that the venom bulbs contain high concentrations of arginine kinase. The presence of this kinase enables the venom bulb to contract very rapidly and repeatedly. That means that the cone snail can quickly force the venom through the venom duct and out through the proboscis and into the harpooned prey. In addition to the kinase, morphological examination of the bulb showed the organ to be highly muscularized. Three distinct muscle layers are separated by a tunic-like collagen sheet and the outer muscle layer, in particular, contains radially, spirally organized collagen fibers. Ok, cool. Layered muscle. What does that matter? Well, if we go back to the squid comparison you see that squids have inner and outer surfaces of muscle lined with collagen tunics. These tunics are stronger than the muscles and prevent the muscle from stretching longitudinally during contraction. This restriction and contraction allows the squid to propel water through it's jet at very high speeds. Now, the cone's venom bulb is less complex but it is likely that the function is similar. So rather than just holding the venom, these researchers found that the venom bulb is an active participant in the injection event itself. Previous studies have shown that the venom is pressurized before injection. This study shows that repeated burst contractions of the venom bulb in combination with the relaxation of the proboscis leads to a sudden ballistic discharge of the radula tooth, where it is shot into the prey and the pressurized venom pumped in by ongoing, repeated burst contractions of the venom bulb (you got an image of that in your head right? Wow!).
Read more in the article:
Safavi-Hemami, Helena , Neil D. Young, Nicholas A. Williamson, Anthony W. Purcell (2010) Proteomic Interrogation of Venom Delivery in Marine Cone Snails: Novel Insights into the Role of the Venom Bulb. Journal of Proteome Research: 9(11), 5610–5619. (DOI: 10.1021/pr100431x)
Learn more about cone shells at these links:
Thursday, November 11, 2010
Saturday, November 6, 2010
Happy Carl Sagan Day!
Carl Sagan was born on November 9th, 1934, and to celebrate the anniversary of his birth there will be an event held today in Broward County Florida (that's in South Florida, folks). The event will be held to increase public involvement in the amazing field that is astronomy and space exploration.
Carl Sagan was the David Duncan Professor of Astronomy and Space Sciences and Director of the Laboratory for Planetary Studies at Cornell University, and you can visit his gravesite in Ithaca, New York to this day. He played an important role in the American space program starting in the 1950's as a consultant and advisor to NASA. He was involved in almost every level, even briefing the Apollo astronauts before their trip to the Moon. He was also a key player in the Mariner, Viking, Voyager, and Galileo missions. His own work focused on planetary atmospheres, planetary surfaces, the history of Earth, and exobiology, solving questions that we almost take for granted now: Why is Venus so hot (answer: massive greenhouse effect), what causes the seasonal changes on Mars (answer: windblown dust), and what is the reddish haze that can be seen on Titan (answer: complex organic molecules)?
Needless to say, he was an extremely productive and influential scientist. He was also known as an extraordinary communicator. Some of his speeches and books are still recognized for their accuracy, foresight, and eloquence. His book The Dragons of Eden: Speculations of the Evolution of Human Intelligence won him the Pulitzer Prize and his book Cosmos became the bestselling science book ever published in English. The lay person probably knows him best from his Emmy winning television show Cosmos, which was watched by people all over the world. Oh, yeah, and have you seen the movie Contact? You can thank Carl for that one too.
So take the day to celebrate Carl, or at least a few minutes to remember all of the amazing contributions he made to science.
Also, take a look at the website for Carl Sagan Day, it has live streaming from some of the events:
Learn all about the life and works of Carl Sagan here:
Scroll through these websites as well:
p.s. No one could rock a turtleneck and jacket like Carl Sagan.
Tuesday, November 2, 2010
Here in the U.S. its Election Day. If you live here, have you voted today?
It never really occurred to me that you need special rules or laws for astronauts. Apparently you do. In 1997 the state of Texas passed a bill allowing astronauts to vote from orbit, and as most astronauts are stationed in Houston that means that they can cast their vote on election day.
All three of the Americans currently on board the International Space Station have cased their votes. Their votes came via complex, secure e-mail system from orbit, 220 miles above us. The six space shuttle astronauts currently on their way to the space station voted last week as they are scheduled to lift off tomorrow.
Live in the U.S.? Haven't voted? What's your excuse?