The wonderpus and the mimic

Did you know that there is a kind of octopus called a wonderpus?

Sounds like a Dr. Seuss creation, doesn't it? But no, it's a real animal! The wonderpus octopus (Wonderpus photogenica) is a beautiful creature, with dark red skin marked by bold, white stripes on the arms and spots on the mantle. These spots are extremely distinctive, and vary for each individual octopus - so much so that they allow for the identification of specific animals. In fact, the wonderpus's distinctive appearance is what enabled its discovery. They are close relatives of another type of octopus called a mimic octopus (Thaumoctopus mimicus). In fact, it is highly likely that people have observed wonderpus for many years, but didn't realize it because it is very similar to the mimic. The mimic, however, has much more muted colors than the wonderpus. It was only in 2006 that scientists realized that mimics and wonderpus were 2 different creatures.

The mimic octopus is, in an of itself, pretty interesting, too. Found in the seas off southeast Asia, the mimic shows an amazing ability to hide itself in plain sight simply by looking like something else. It has been observed disguising itself as more than a dozen different species, including sea snakes, crabs, stingrays, jellyfish and sea anemones. It accomplishes this amazing feat of deception by altering the color and texture of its skin, as well as contorting its arms with a high degree of flexibility. While all octopus are able to hide themselves with camouflage, the mimic is unique in its ability to not just blend in to the environment, but to actively disguise itself to look like something else. While that makes it difficult for predators to find the mimic, it also makes it difficult for scientists to find them!

Deep sea creatures

The other night I was watching one of the episodes of the Discovery channel's documentary "Planet Earth." In case you haven't seen any of these shows, they are truly amazing. They captured some of the most amazing video of creatures in places all over the globe - from the topics of mountains to the depths of the sea, from the lushest jungles to the most barren stretches of desert, from the poles to the equator - and everything in between. In the episode "Deep Ocean," the viewer is introduced to the largest habitat on the planet - the sea.

Deep ocean is considered anything away from the coasts and beyond the continental shelves. Out in these areas, the water can reach several miles deep. Historically, water this deep has been impossible for man to reach - the crushing pressure associated with it has been too much to overcome. But while it is too deep for man, it is not too deep for machine. In recent years, the use of remote underwater submersibles has allowed scientists to see just what is down there in the deepest parts of the world. And it turns out that this region, once considered barren and devoid of life, is not quite the wasteland we once believed. In fact, the deepest oceans in the world contain some amazing life. Amazing - and quite bizarre!

Here are a few examples of what lives in the depths of the world. (Some of these creatures are very poorly understood, given how hard it is to even find them.)
Vampire squid: The Vampire squid lives at depths of 2000 feet or more in what is called the OMZ, the oxygen minimum zone. At this depth, the amount of oxygen in the water is too low to sustain life in most oxygen-utilizing higher organisms. However, the vampire squid survives - and even thrives - in water with as little oxygen as 3%. (It is the only known cephalopod capable of this.) Interestingly, the vampire squid uses light as a defense mechanism. While shallower-dwelling squid squirt ink when startled, the vampire squid instead squirts a bioluminscent mucus that can glow for up to 10 minutes. This presumably blinds would-be predators in the inky darkness of the deep sea, allowing the squid to escape.

Sawtooth eels: These eels are so named for their inward-slanted teeth, arranged in a saw-like pattern. There are 11 known species of sawtooth eel, and they live in waters up to 2000 feet deep.

Tube worms: Tube worms are arguably some of the most well-understood deep water creature. Tube worms live around deep sea hydrothermal vents. The giant tube worm is the easiest to recognize - they can reach up to 4 feet tall, and grow more than 33 inches a year. Giant tube worms are only found in the Pacific ocean; other oceans contain tube worms such as Jericho worms, benthic worms and palm worms. These worms have a symbiotic relationship with deep see vent bacteria, which colonize the worms and provide them with energy as a byproduct of bacterial metabolism.

There are no doubt countless deep sea creatures that we know nothing of, given how difficult it is to get down there. But what little we do know about the creatures who make this region home makes me really appreciate how amazingly diverse a planet we live on.

All things baby and science-y

Hi everyone! I'm starting to get back into the swing of things after the birth of our daughter, which means I'm hopefully going to be able to start blogging again! Over the last 3 months, my brain has been all-consumed with all things baby-related, so I thought I'd start off with the list of baby-related science thoughts.

1. Cradle cap: Our daughter had a pretty severe case of it. For those of you unfamiliar with it, this is a skin condition characterized by thick, scaly flakes on the scalp, forehead and eyebrows. Some babies get it, some do not. But we really don't know what causes it. It seems to have something to do with the same reason why many adults get dandruff. Who knew - apparently it's not just a case of dry skin!

2. Hearing tests: Newborns are given hearing tests these days before they even leave the hospital. It's pretty neat how it's done, too, considering that a newborn can't tell you whether she's heard a noise or not. Sensors are attached to their foreheads, and then a tone is played in their ears. If they hear it, the sensors detect the neuronal signals passing through their brains, and output a signal to the detection machine. From a parenting standpoint, it was a relief to know that our daughter's hearing was normal. From a science standpoint, the process was really neat.

3. Colic: We were extremely fortunate to have a non-colicky baby. Many parents are not so fortunate. Despite it's prevalence, however, colic is poorly understood. Some believe that many cases of colic are actually undiagnosed cases of acid reflux (otherwise known as heartburn). But what about those colicky babies who do not have reflux? No one really knows why they have such a fussy time during their first 3 months of life.

4. Speaking of reflux: Did you know that the sphincter that closes the stomach off from the esophagus actually weakens from birth until about 4 months of age? Only after that does it begin to get stronger. That's what babies do most of their spitting-up between the ages of 2 and 4 months.

5. Baby fingernails: These are really amazing. Baby fingernails are so soft and pliable - and yet incredibly sharp! If you don't keep them trimmed, a baby can give herself or you some strong scratches. I wonder when they start to become harder, like adult fingernails?

6. Baby blue eyes: Like many Caucasian babies, our daughter has started life with blue eyes. We strongly suspect that they will change color as she ages - many babies develop their adult eye color at around 6 months. But here's a question - why would a baby's eye color change from blue to something else? Why aren't they born with their final eye color?

7. SIDS: That dreaded fear of all parents - sudden infant death syndrome. A small percentage of babies suddenly stop breathing while sleeping, and thus they die. It's been known about for centuries, and the reasons for it are still a mystery. Here's some good news, however. The risk of a baby dying of SIDS has been drastically reduced in recent years due to current recommendations that babies sleep on their backs. While we may not know why this reduces the risk of SIDS so much, I'm grateful for it!

These are just a few of the science type thoughts I've had in the last few months related to parenthood. I'm sure I'll come up with many others, and I strongly suspect that my posts for a while will all relate to baby topics. Hopefully you'll all find this as interesting as I do these days!

An update

For those of you who've been wondering where I've been, my family has been a little busy with the recent birth of our daughter. Please be patient! I will start posting entries again in the near future.

More than just bed-head: UHS

I came across an article on a news website today that I read and thought, "this has got to be a joke." The article was entitled "The tangled truth about uncombable hair," and it began with the following sentence:
"If ever there were a disease designed to vex a mother, it’s uncombable hair syndrome (UHS)."

You're joking, right? Uncombable Hair Syndrome? They came up with a disease name for when someone has messy hair? As I read on, I became more disbelieving; my disbelief was not helped by the statement that it was first described 35 years ago in a French medical study, which called it "cheveux incoiffables." Okay, now I know you're pulling my leg, right?

Actually, much to my surprise, no! This story is legit. This syndrome is legit. It may sound wacky, but it's for real. Some people have messy hair. Some people have hair that is easily tangled. Some people have truly horrible cases of bed-head when they get up in the morning. But others have truly uncontrollable hair.

Uncombable Hair Syndrome is also known as Pili trianguli at canaliculi, or Spun Glass Hair. This syndrome can manifest itself in children anytime between the ages of 3 months and 12 years old. While these kids start out with hair that looks thin and glassy (though still relatively normal), the hair begins to become drier, curlier and lighter in color. Eventually, it stands straight out from the scalp and is literally impossible to comb flat.

The reason for this disorder lies in an abnormality in the hair shafts of the affected individual. When examined under high magnification, these hair shafts have 2 unique qualities. First, their cross-section is shaped like a kidney bean (instead of a circle). And second, there is a deep groove or canal that runs down the entire length of the hair. This makes the hair unable to bend like normal hair without such a groove. So it stands straight out from the scalp. But here's the good news. Kids with UHS usually outgrow it. So while their hair may be unmanageable now, it'll get better as they get older.

But in case you're wondering whether your messy hairdo could be the result of UHS, the odds are quite strong that it's not - UHS is an incredible rare syndrome. In the last 35 years, barely 100 cases have been reported in the medical literature.

It's far more likely that you just have easily tangled hair.

In honor of the start of school

I thought I’d write an entry in honor of all of the children, teachers and administrators in our country who are just starting up another year of school. The start of the school year brings lots of exciting opportunities, does it not? New books, new subjects, new friends, new challenges – oh, and of course, the possibility of new illnesses. Sometimes school seems the perfect place for the propagation of viruses, bacteria and other assorted bugs. And it’s one of these bugs I want to discuss today – the ever-popular, ever-fun, and ever-exciting pediculosis. Otherwise known as head lice.

What are head lice? A head louse (singular, as opposed to the plural form lice) is a small, wingless insect that lives among human hairs and feeds off small amounts of human blood. How small are they? Lice go through three stages during their life cycle. They start out as eggs, otherwise known as nits. These are very small, about the size of a flake of dandruff. About 7 days after the nits are laid by a female, the lice hatch into the nymph stage. Nymphs look like adult lice, but they’re much smaller. At this point, they need human blood to survive to adult. If they feed enough, after about 7 days as a nymph, they will mature into adult lice, capable of laying their own nits. Adult head lice are tan to grayish-white and about the size of a sesame seed, easily visible to the naked eye; so if you’re going to spot an infestation, it’s the adults you want to be on the lookout for. And adult louse can survive for around 30 days as long as it keeps feeding; if it falls off its human’s head, however, it will die within about 2 days.

Here’s a few facts about head lice that I did not know before I started looking into them:
Head lice cannot survive on any animal besides a human. That means you cannot catch head lice from your pets – cat or dog blood will not sustain a louse.
Head lice cannot jump or fly from head to head. The only way to pass head lice among people is for them to come into direct contact with hair that has a nymph or an adult louse clinging to it. Once that contact is made, the louse can transfer itself to the new person’s head and begin feeding.
Head lice have very strong claws that allow them to hang on very tightly to a strand of hair.
Dessicated head lice and head lice nits have been found on the hair and scalps of Egyptian mummies.
It is believed that 1 in 10 kids in America will come down with head lice at some point during their lives.

Okay, now that I’ve given myself the creeps over imagining all these little bugs crawling over my scalp…

An update from MESSENGER

In February of this year, I wrote an entry about the MESSENGER spacecraft, NASA's recent expedition aimed at learning more about the planet Mercury. Despite being relatively close to us in the solar system (a few scant planets away), we know relatively little about this rocky planet. MESSENGER is an attempt to answer some long-standing questions about the planet, including (if you remember from my previous post) what half of the planet even looks like! I figured it was about time to give you an update on what MESSENGER's been up recently.

Some of the latest news to come from the MESSENGER mission concerns the origin of Mercury's magnetic field. The question of what exactly is a magnetic field opens the door to a big area of physics called electricity and magnetism. I'm not going to go into a lot of detail about magnetism - at least, not right now. I will tell you that a magnetic field is a a field that permeates space and exerts a magnetic force on moving electrical charges and magnets (otherwise known as magnetic dipoles). Earth (as I'm sure you know) has a magnetic field; this fact gives us north and south. There does not appear to be a simple answer for why Earth has a magnetic field. It seems that it has something to do with our rotation. We believe this because the planet Venus, though it has a similar iron core to Earth's, has a different rotation pattern and has no magnetic field itself. Earth's rotation may generate something called a dynamo effect, causing the fluid iron in the core of our planet to circulate. At the same time, convection occurs, drawing the hottest part of the molten iron away from the center of the planet towards the surface. This combination of rotation and convection generates electric currents, which in turn generates and sustains our magnetic field.

Now, while it's long been known that Mercury has a magnetic field (though it is about 100 times weaker than our own), why it does so has been a mystery. Scientists had believed that Mercury's iron core was thought to have cooled long ago; a lack of fluidity in the core would make it incapable of generating a dynamo effect. But it turns out that Mercury's core is not as quiet as they once believed. The latest news from MESSENGER seems to indicate that a combination of volcanic activity and fluidity in Mercury's core is responsible for the generation of this magnetic field.

Of course, as is always the case in science, as soon as one question is answered, another is posed. The question now is not "why does Mercury have a magnetic field," but "why is Mercury's core still molten?" For the answer to that one, however, it looks like we'll have to wait for more data from MESSENGER, and another announcement from NASA.

In the meantime, here are a few other facts about Mercury that NASA has announced from the latest data from the spacecraft:
1. Mercury appears to have active volcanic vents around something called the Caloris basin, This is one of the solar system's largest and youngest impact basin - a basin formed by an impact with an asteroid or comet during the first billion years in the history of the solar system.
2. The planet has shrunk in on itself more than anyone had ever expected - in fact, the planet seems to have shrunk one-third more than anyone predicted
3. The magnetosphere around Mercury is more complex than scientists had predicted. The magnetosphere (a kind of bubble around the planet that contains atomic and molecular particles) contains more complex particles than had been expected, given how close it is to the sun. In fact, many of the particles themselves originate from the planet, and are not carried there by solar wind.

MESSENGER is supposed to make another flyby of the planet in October, so I'm sure that more news about Mercury will be coming shortly. Until then, if you want to see a really interesting picture from the latest set of data, check out picture of the Caloris basin on the MESSENGER website at:
http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=193

Octopus - up close and personal

I wanted to write a quick post about a topic I've written on before - octopus. In May, I wrote an entry about the intelligence of octopus (and I don't know about you, but some of what I learned certainly surprised me!). Well, my husband and I recently came home from a vacation in Hawaii. We both love to snorkel and scuba dive, and though we weren't able to do any scuba diving this trip, we did get in some great snorkeling. And this time we saw something we've never seen before while in the ocean - an octopus.

Now, we strongly suspect that there are octopus all over the areas where we often snorkel. The rocks and coral have so many cracks and fissures that there are ample hiding places for them. There are also significant numbers of moray eels in the area, and octopus are a tasty snack for a moray (if it can catch one, that is). And finally, we've heard other people say they've seen octopus around there before. So we knew that they were there. But we've never seen one before.

I think there are 2 main reasons for this. First, octopus are nocturnal, and we always snorkel during the day. And second, octopus are really, really, really good at hiding - especially when it comes to camouflage! An octopus sitting motionless in a crevice looks just like a rock - brown and bumpy. Put that "rock" 10 feet below the surface of the water, and a snorkeler swimming over the top of it will never see it.

However, this year we were extremely fortunate. We managed to see an octopus as it was moving to a new hidey-hole. It was fairly easy to see it when it was in motion; moreover, once it was settled into its new spot, we knew where to look for it, and were able to watch it quite easily. It was pretty big, maybe 2 feet long from the head to the tips of the arms, much longer than I ever expected to see in the wild. And perhaps the coolest thing about it was the way that it would rapidly change colors when one of us swam close to it. It would instantly switch from rock-brown to dark red, then fade back to brown when we backed off. I think that means we were spooking it a little bit!

We saw quite a few other interesting sea creatures while snorkeling this year, as well, including both the largest and the smallest moray eels we've ever seen (the largest being probably close to 4 feet long, and the smallest being only several inches), and a huge devil scorpionfish. This has to be one of the uglier fish I've ever seen. They sit on the bottom of the ocean, disguising themselves as rocks. They kind of look like a fishy equivalent of a gargoyle, actually - lumpy, brown, and extremely grumpy looking. And while you don't want to touch these guys (yes, they are poisonous), being able to find one is actually quite a treat. (Can you see the face of this one on the right-hand side of the picture, with a fin in the bottom left corner?)

I'm sure there were all kinds of interesting creatures in the ocean where we were snorkeling that we never even saw. But I think we were very fortunate to find the things that we did! Of course, the next time we go, I'll be on the lookout for even bigger and better things.

All about popcorn

Did you know that popcorn is made from a special kind of corn? I had never really thought about it before, but if asked, I would have guessed that you could use any old corn to make popcorn. All you have to do is dry some kernels, then heat them up and they'll pop, correct?

Actually, no, it turns out that popcorn is a little more sophisticated than that. In researching how it's more sophisticated, I've learned some things about corn that I never knew before.

All corn is a type of maize, of which there are 6 kinds - pod, sweet, flour, dent, flint and pop. The kernels of all kinds of corn are made of 3 things - the germ, the endosperm and the pericarp. The germ is the only living part of the kernel. It's right in the middle of the kernel, and contains the information necessary for that kernel to produce a whole new corn plant (genetic material, enzymes, vitamins and minerals). It's also the part of the kernel that produces corn oil - about 25% of the germ consists of corn oil. The endosperm is the largest part of the kernel. It accounts for over 80% of the kernel's dry weight, and consists largely of starch. The endosperm lies between the germ and the pericarp, or outer hull. The pericarp is very tough, and is designed to prevent moisture loss from the inside of the kernel, as well as protecting the delicate germ from being eaten by bugs or microbes.

Different kinds of corn differ in how much of these 3 components the kernels have, as well as their starch and oil composition. Dent corn, for example (the leading type of corn grown on US farms), has an endosperm consisting of horny starch on the sides and soft starch on the top. As the kernels age, the soft starch shrinks, making a characteristic "dent" in the top of the kernel. Flint corn has no soft starch at the top of the endosperm, so it does not make a dent as it matures. The endosperm of flour corn consists mainly of soft starch, which makes it very easy to grind into flour. Sweet corn, grown for human consumption, has much less starch than any other kind. That's because the sugar in the kernels is not converted into starch in the endosperm - hence the sweet nature of the food. Pod corn is a very pretty kind of corn, with kernels that often turn a variety of colors. It is not eaten very often, but instead is grown to use for decorative purposes. And then, of course, there is popcorn.



Popcorn is specifically - and scientifically - known as Zea mays everta. It is a derivative of flint corn, and is distinctive in that it has a very thick pericarp. The thickness of its pericarp allows for the popping process to occur. When the water inside the germ is heated, it turns into steam. The thick pericarp holds the steam in, where it begins to gelatinize the internal starch and protein in the endosperm. Once the pressure of the steam gets too great, the pericarp bursts, releasing the starch protein and steam in a big pop. As the starch expands, it cools and solidifies into its distinctive popcorn shape.

There are several variables that go into how well popcorn will pop. One important factor is how quickly the popcorn is heated. The internal temperature has to reach about 180 degrees celsius (356 degrees fahernheit) before it will burst. If the kernel is heated too quickly, the external portion of the endosperm will release steam too quickly, bursting the pericarp before the internal part cooks properly. If it is heated too slowly, the building steam may leak out of the tip of the kernel, and it won't pop at all. Popping quality also depends on how much moisture the kernel contains. If there is a lot of moisture in the kernel, it will pop into chewy, soggy pieces of popcorn. Also, very moist kernels of popcorn tend to go moldy easily. If the kernel is too dry, however, it will not produce enough steam to pop well. So popcorn growers usually carefully control the moisture level of their popcorn kernels, and try to dry them out to around 15% of the total kernel weight being moisture.

There are lots of other interesting facts about popcorn that I came across when writing this entry. Here are a few of my favorites:


1. Popcorn usually pops in one of 2 shapes - mushroom (on the left) or snowflake (on the right). Different kinds of popcorn can produce exclusively one shape or the other, or a mix of the 2. Snowflake popcorn is usually used for eating straight as popcorn, which mushroom popcorn is usually used for popcorn confections (like caramel corn).

2. Popcorn kernels can move a distance of up to 3 feet when they burst.


3. "Popability" refers to how many kernels of a given batch of popcorn will pop. Some kernels simply do not pop, and are known in the popcorn industry as "old maids." They are assumed to either by too dry to produce enough steam, or have too leaky a pericarp.


4. Popcorn is the official state snack food of Illinois - which, by the way, produces a lot of the US supply of popcorn.


5. Scientists have found popcorn kernels over 1000 years old in tombs in both Peru and southwestern Utah.



Personally, I really enjoy eating popcorn. And I'm not alone. Apparently, Americans consume an average of somewhere around 17 billion quarts of the stuff per year. That's a lot of popcorn!

Sitting in the catbird seat

I was in the car this morning, and one of my favorite programs on NPR came on the radio. It's a short little thing, usually just 2 or 3 minutes long, but it's always so interesting! The program is called "Bird Note," and every episode describes something about birds. Wild or tame, big or small, common or rare, showy or drab - it runs the gamut. The narrator sometimes talks about the behaviour of the birds, or their environment, or their plumage. One particularly interesting one a few weeks ago compared how much effort it would be for a human to build a nest comparable to that made by a robin. (It would actually be really, really difficult!) Today's show was about a bird called a catbird. Actually, it was about an idiom in which the catbird features prominently - as you might have guessed from the title, the idiom is "sitting in the catbird seat."

I'd never heard this phrase before, but the narrator explained that this phrase means having an enviable position, the upper hand, or the greater advantage in a situation. And the reason it means this is perfectly explained by the behavior of the catbird.

Catbirds are American birds of the mimid family. "Mimid" is Latin for "mimic," and mimids are known for the vocalization abilities. Other mimids include thrashers, mockingbirds and tremblers. The catbird's standard call sounds roughly like a yowling cat, actually, though it can also imitate other birds. (It's alarm or warning call sounds startlingly similar to a male mallard.) There are two kinds of North American catbirds. The grey catbird is the most common, and is found across the US in all kinds of environments (rural, suburban and urban). They are medium-sized and dark in color, with the only notable coloration being a rust-colored patch under their tails. The other kind of catbird is the black catbird, which is found more in Central America and Mexico.

So what does the catbird do to deserve having an entire idiom phrased after it? The catbird (like many animals) relies on height to assert superiority or dominance. If a catbird feels threatened, it will go to the highest position it can find to call out its warning call. The higher that position, the more likely the intruder will back off. In addition, if two male catbirds are jockeying to be the top male in the area (and thus attract the best female), they will take gradually higher and higher perches, trying to outsing the other, until one is at the highest point. The bird who gets the highest is the winner. And, of course, the high perch from which he claims his victory is called "the catbird seat."

So there you go. Sitting in the catbird seat means getting the most advantageous position.

I love finding examples of how something science-related has worked its way into everyday life and language. Okay, so maybe this phrase isn't the most common, everyday phrase you'll ever hear. But now, if you ever do hear it again, not only will you know what it means, you'll also know where it comes from!

Anyone have any other suggestions for phrases or idioms that have their origins in science?

The science of fireworks

In recognition of the fact that tomorrow is the 4th of July, I'd like to spend today's post talking about fireworks. I love watching fireworks - the colors, the shapes, the sizes, and the different ways they twirl and burst and shimmer and sparkle are all entrancing to me. In thinking about fireworks, I wanted to investigate and see if what I think I know about fireworks is really true. In particular, I wanted to look into the science behind what makes fireworks different colors. I believe that I already know a little bit of the answer (as may you), but since it never hurts to have our knowledge expanded upon, here we go...

First, let's talk about the kind of firework that we are most familiar with in fireworks displays during the 4th of July - skyrockets. Skyrockets are projected into the air before they explode (unlike ground fireworks such as catherine wheels, which are like small, glowing ferris wheels that spin as they burn). These are built around a basic design - paper or pasteboard tubing filled with a combustible material, called pyrotechnic stars. Different tubes filled with different pyrotechnic stars can be combined in various ways to make the many shapes, sizes and colors that are seen when the firework explodes.

Pyrotechnic stars contain 5 basic components. First, there must be a combustible fuel to burn. Second, there is an oxidizer. This provides the oxygen required to start the burning process in the first place. (For a reminder about oxidizers, you can read my entry on flaming gummy bears.) Third, there is also something to hold the entire firework together, called the binder. And finally, there are chemicals which burn to provide the color, as well as another chemical to help strengthen the color of the flame produced.

So I was right - the color is provided by the burning of certain chemicals. Here's something I didn't know - a few of the chemicals that are used in producing fireworks displays:
Red: strontium or lithium salts
Orange: calcium chloride or calcium sulfate
Yellow: sodium salts such as sodium nitrate or cryolite
White: magnesium, aluminum or barium oxide
Green: Barium chloride
Blue: Copper chloride
Silver: Titanium or magnesium

Apparently, the most difficult color to achieve is blue. That's because copper is a tricky metal to burn. If it does not reach a high enough temperature, it will not emit enough light to be seen. However, if it gets too hot, it will fall apart before it produces any light at all. So consider yourself lucky if you wee a blue firework! Actually, all of the color-producing chemicals have to be handled carefully to achieve the right color. If there is a small amount of chemical impurity, thee metal will not burn properly. In particular, trace amounts of sodium burn so well that they easily overpower the intended color, producing yellow-orange instead.

I think my favorite kind of firework is called the willow firework. What's a willow firework? Well, your basic firework is called a peony. It makes a spherical burst of colored stars. Building off that, your next most common firework is the chrysanthemum, which is like a peony but with longer burning stars which leave a visible trail behind them. The willow firework is a variation on a chrysanthemum, but it has extremely long burning silver or gold stars. These burn so long that a long trail of sparks can be seen falling gracefully to the ground, just like a weeping willow tree.

Unfortunately, this year we probably will not watch a display of fireworks ourselves, but we may get to watch one on TV. Of course, it's not quite the same as in person, but it's better than nothing!

Catnip - a really good kitty drug

I've said it before, and I'll say it again - science is everywhere, all around us, in so many different things that we see all the time. I am reminded of that quite frequently when I spend a few minutes looking at our cats. There are many things that our two kitties do that spark questions in my mind, and today is no exception. What I want to explore today is the following question - how does catnip work?

For those of you with cats, you are probably familiar with what catnip does to a cat. But for those of you who don't, let me describe a scene for you. We have a toy for our cats that is a catnip-stuffed mouse. Fairly standard, as far as housecat toys go, but this one is a cut above most catnip-stuffed mice in that it has a pouch inside of it that you can refill with new catnip. So as the cats play with the mouse, though the catnip (a) slowly loses potency and (b) slowly leaks out of the pouch, it doesn't matter, because we can put new, fresh catnip in. Now, right after we fill the mouse with new catnip, it's quite amusing to watch our cats play with it. They rub their faces all over it, they lick it over and over again (until it's drenched in cat spit), they bat it around and around and around, and then they run like maniacs chasing it. And, just so you know, this is the only toy that causes them to act like this. (This is not really normal behavior for them). It's the fresh catnip - they love it. Love, love, love, love, love it! And from what I understand, our cats are not alone in their catnip obsession. Many cats love catnip. About 70-80% of domestic cats have some sort of reaction to it. They love to smell it, roll in it, lick it, rub their faces in it, and it tends to make them go a little bit nutso. Honestly, it's like a kitty drug!

So I was watching this unfold the other day, and I wondered - why does catnip affect cats so strongly?

Catnip is an herb related to mint. It's native to Europe, Asia and Africa, but has long since been established in the Americas, too. It's not entirely clear why it has such a potent affect on most cats, but here's what I've been able to find out. Catnip leaves contain a volatile oil (volatile means that it vaporizes easily) called nepetalactone. The nasal passages of cats is sensitive to this oil; when cats smell the oil, it stimulates sensory neurons that transmit messges to several parts of the cat's brain. In particular, it stimulates the amygdala (which controls emotional response to stimuli) and the hypothalamus (which regulates lots of different activities including emotions). The stimulation of these two areas of the brain cause the intense emotional reaction to the herb.

There are a few things that should be noted about catnip. First, cats will become desensitized to it after a few minutes. This seems to be analogous to how our noses become desensitized to a particular odor if we'rearound it long enough. A cat will only respond to catnip for a short while, then it ceases to have an effect. However, if they walk away from it for a while, then come back, their noses will be sensitive to it again. Second, it is not addictive. Cats do not become dependent on it, no matter how much of it they have. Third, it apparently has no effect in humans. This is presumably because our noses do not have the receptor for the nepetalactone oil. And finally, even large cats like tigers and lions appear to be susceptible to it.

I think it would be fairly amusing to watch a big, ferocious tiger rolling around, rubbing his face in a catnip bush! It would strike me as fairly undignified, for what is otherwise a thoroughly dignified animal.

New creatures

As I was scanning through the news this morning, I came across a story on msnbc entitled “Top 10 new species: only the coolest, weirdest – and deadliest – made the list.” Intrigued, I scrolled through the pictures on new life forms that have been discovered in various places on the planet over the last year. Here are a few highlights from the article:
Magaceras briansaltini: this is a new kind of rhinoceros beetle. Rhinoceros beetles are certainly nothing new, but this one has a completely different kind of horn than anyone has ever seen. Well, that’s not completely true – the horn has been seen before, but only in an animated cartoon. Remember Dim, the beetle from the Pixar movie “A Bug’s Life”? This new beetle looks exactly like him – only it’s black, not cartoon blue.
Xerocomus silwoodensis: This new mushroom species was discovered, surprisingly enough, in the relatively high-traffic area of Silwood Campus, a campus of Imperial College in London. Odd, how no one noticed it before this year, isn’t it?
Oxyuranus temporalis: This is the second most poisonous snake ever discovered. The other snakes that compete with this guy in terms of lethality are its 2 closest relatives – the inland taipan snake and the coastal taipan snake (which are ranked numbers 1 and 3 on the scale of snakes you don’t want to bite you). It was found in an isolated region of Australia.
Desmoxytes purpurosea: This one tops the list of these new creatures on my “yuck” scale, because it is a big bug with lots of legs. (You might remember from several of my previous posts that I’m not a big fan of bugs.) It’s a millipede, and what makes this species worthy of note is its shockingly bright pink color. It’s so pink, it almost looks fake – but apparently, its notable color is enough to scare away most would-be predators. That’s good for the predators, of course, since this creature also happens to be very inedible – spiny and poisonous.

The list also had a new jellyfish (highly toxic), a tubular plant (described as “having the appearance of the Michelin man”), and a frog specimen preserved in a museum that is now believed to be extinct in the wild. I knew that this list was merely the 10 new species this particular author found most interesting, and I wondered what other new species have been reported in the last few years that didn’t make the cut. Here are a few of the other new creatures that I’ve come across that I thought were worth note:
Rhynochocyon udzungwensis: This is a new type of giant elephant shrew, or sengi. The size of a house cat, this creature looks a but like a cross between a small anteater and a miniature antelope – 4 spindly legs, a stout, amber-colored body, a grey face, and a long, flexible snout. Despite its name, it’s not really a shrew at all, but a relative of African mammals like elephants and aardvarks. There are some 15 species of sengi previously known, but this one had never been sighted before, until first caught on film in the Ndundulu Forest in Tanzania’s Udzungwa Mountains in 2005.
Melipotes fumigatus: This is the only bird I’ve included in my list. It was discovered in New Guinea, on the same expedition that found numerous other species (including 20 new frogs that I won’t talk about here.) This bird is also known as a smoky honeyeater, and it is the first new bird species to be discovered on New Guinea for nearly 70 years.
And finally, Dendrolagus pulcherrimus: This species is more commonly referred to as the golden-mantled tree kangaroo. Also discovered on New Guinea, it’s the rarest arboreal, jungle-dwelling kangaroo in the world. Actually, I’ve cheated a little by including this species, since it was already known to exist in the Foja Mountains of Indonesia, but this is only the second place in the world that the animal has been sighted. But I included it, because I think it’s the cutest of the entire bunch I’ve looked at!

All in all, hundred of new species have been described over the last year. These creatures run the gamut in type, habitat, size, shape and purpose - parasites, plants, fungi, insects, fish, birds, mammals, and amphibians. Of course, since they’re so new, not much is known about many of them yet! I think it’s amazing that, despite the global nature of today’s world, there are still so many things about our planet that we don’t know. And these mysteries are not always even found in the deep jungles of New Guinea – sometimes they’re found right under our noses, or in the courtyards of the Imperial College in London.

The power of oses

Today I’d like to write about oses. What, you might wonder, are oses? Well, that’s actually a nickname I’ve come up with for the wide variety of sugars that are found in the foods that we eat. Since the proper name for all sugars ends in –ose (I’ll give you a few examples in a minute), I like to call them all “oses.” (It saves me some effort.)

When I say sugar, you might think of granulated sugar, that gritty white stuff we use to sweeten things when we cook. But that is only one specific kind of sugar – specifically, it is sucrose. (See, it ends in –ose.) There are actually dozens of varieties of sugars in the world. What, chemically speaking, is a sugar?

Sugar is a carbohydrate. Carbohydrates come in 2 basic varieties, actually, sugars and starches. Starches are the biggest source of carbohydrates that we eat, but sugars are themselves very important sources of carbohydrates, as well. There are 4 major kinds of sugar that we come into contact with regularly – 3 come from plants and 1 from animals. The 3 plant sugars are called sucrose (what we know of as baking sugar), fructose and glucose.

Fructose is the sweetest of all natural sugars. Its chemical structure is very simple – 6 carbons, 6 oxygens, and 12 hydrogens. It is found in a variety of plant sources, including tree fruits, berries, melons and root vegetables. Chemically speaking, it is actually very similar to glucose; they both have the same numbers and types of atoms, those atoms are simply connected differently in the 2 different sugars. Glucose is the least sweet of the three major plant sugars, but it is the primary source of energy for living cells of all kinds (plants and animals). Sucrose is also commonly known as saccharose, and it is known as a disaccharide. That means it is made up of 2 pieces of glucose and fructose that are bonded together in a specific way. It is the plant sugar that is intermediate in its sweetness between its 2 cousins.

Various food items that we think of as sweet usually actually contain a mixture of the three plant sugars. For example, honey is a mixture of glucose, fructose and sucrose (80% sugars, 20% water). Maple sugar (which makes up maple syrup) is mostly sucrose. Molasses is a byproduct of sugarcane or beet sugar, which is also primarily sucrose. High fructose corn syrup is actually only about 45-55% fructose, the rest of the sugar being a mixture of sucrose and glucose.

The 1 major animal sugar is called lactose. Lactose is found in the milk of all mammals, though it is not as sweet as the plant sugars That means that, though milk has a relatively high sugar content, it doesn’t taste as sweet as something sweetened with sucrose, fructose or glucose. Of course, the rest of a mammal’s body (blood and muscles) also contains sugar in the form of glucose. After all, it is the major energy supply for metabolism. However, mammals do not synthesize glucose out of the constituent atoms – they produce it by converting any other kind of sugar they eat into it.

I know that sugar gets a bad reputation, some of it deserved. After all, our diets are higher in sugar (eg higher in sucrose) than is probably good for us. And a little sugar goes a long way, so we don’t really need to eat as much as we do. But sugar does have a very important place in our metabolism, as well as in making food palatable (actually, making it quite yummy sometimes). So don’t throw the baby out with the bath water, equating sugar with all things bad and horrible. Like everything, just take in moderation.

Antacids - chemistry in action

Since becoming pregnant, I’ve become acquainted with an uncomfortable stomach reality – heartburn. Or, more properly termed, pyrosis. If you’ve never had heartburn before, let me introduce you to the phenomenon. Your stomach is a very acidic environment – it has to be, to digest everything that you eat. The acid produced by your stomach is supposed to be kept in your stomach and out of your esophagus (the tube connecting your mouth to your digestive tract) through the action of the esophageal sphincter. It’s supposed to be a one-way valve that lets food and liquid from the esophagus into the stomach, but not the other way around. However, sometimes that sphincter doesn’t work very well, and stomach juices push up out of your stomach and into your esophagus. And as these juices are strongly acidic, they can burn whatever they touch; in this case, that would be the lining of your esophagus. This doesn’t really have anything to do with your heart, making heartburn rather poorly named. But since the burning sensation occurs right behind your breastbone, and in severe cases, radiate through the rest of your chest, I guess it makes sense for it to have gotten that name somewhere in the past.

Okay, so that’s heartburn – a burning sensation occurring in your esophagus. Fortunately for mild cases, there is a very simple remedy. Antacids. How do antacids work? It’s actually very simple chemistry in action. To stop heartburn, you want to stop the ability of the rising stomach acid to burn your esophagus. In other words, you want to neutralize the stomach acid. The opposite of an acid is a base. If you combine an acid and a base, they cancel each other out , resulting in something either neutral or closer to neutral than you started with (depending, of course, on the strength of each one). So, very simply, antacids contain some sort of base to help neutralize the stomach acid they encounter.

There are multiple kinds of antacids, each using a different chemical formulation to help neutralize stomach acid. Some, like Tums, use calcium carbonate. Others, like Alka-Seltzer, use sodium bicarbonate instead. There are also magnesium salt-based antacids, like Maalox and Mylanta. Each formula works very effectively, but there are limitations to them. People with hypertension have to be careful not to ingest too much sodium, so sodium bicarbonate antacids may not be recommended. And excess calcium or magnesium can cause kidney stones, so you don’t want to take too much of the other ones, either. All in all, antacids are like any over-the-counter medicine, I guess – you still have to be smart with what you take.

Incidentally, pregnant women frequently experience heartburn because there is less and less room in the abdomen as the baby grows. This puts pressure on the bottom of the stomach, often pushing the stomach juices up into the esophagus. But it’s not really that big a deal, at least for me. A few Tums usually clears things right up!

Yay for chemistry in action!

The rubella vaccine

Today I want to write about something that has bothered me for a while, but which has intensified since I became pregnant. And I know that I run the risk of jumping into a rat’s nest of controversy, as there are many people who passionately believe in one side or another of this controversy. But hey, science is sometimes controversial, so I’ll just take a deep breath and plunge right in.

I want to talk about childhood vaccinations.

You might have heard a lot of stories on the news or in the papers in the last few years about the controversy over vaccinations. Do kids really need them, should they get them, or (and this is really the favorite topic in the media) is the increase in the rate of vaccinations connected with the increased rate of autism in today’s children?

I consider myself very well educated on these topics, and let me just put my position out there. I do not believe there to be any credible scientific backing behind the purported link between vaccinations and autism. I think any “scientific” evidence supporting it is spurious at best. I understand that autism is on the rise among today’s children, my heart breaks for those families with autistic children, and I easily understand how they might want an answer for what has caused the condition. But the science just does not support their claim that it is due to vaccinations.

That’s all I want to say about the recent controversy over vaccines. The main focus of what I want to say about the decision of whether to have your children vaccinated or not is not simply, as I have heard it said, a personal decision. Yes,, it is personal. But it is also a social decision as well. Here’s what I mean.

Rubella, or German measles, is not a very common disease these days (at least in the US). That’s because vaccinations against rubella have been going on for years – it’s a part of the MMR vaccine, and it’s very effective. Some may argue that it’s silly to vaccinate against rubella. Actually, compared to regular measles, rubella is usually pretty mild. You might have a rash, low grade fever, swollen glands, headaches and body aches. Or you might not ever really notice that you have it at all. But here’s the sticky thing. While rubella might not be all that dangerous for children or adults, it is devastating to pregnant women and their unborn children. A pregnant woman who contracts rubella within the first 20 weeks of her pregnancy has a significantly increased risk of spontaneous miscarriage. And even if disease doesn’t kill her child, it is at high risk for congenital rubella syndrome. This syndrome includes a host of birth defects, including heart malformations, deafness, mental retardation, eye defects, low birth weight, or problems with the spleen, liver or bone marrow. These problem can plague a child for the rest of his life.

The easiest way for mothers to protect their unborn children against congenital rubella syndrome is to be vaccinated themselves. That way, even if they encounter someone with rubella, they and their baby will be protected. But here’s what I worry about: I’m sure there are plenty of women who don’t know of the dangers that rubella poses. And so their vaccinations are not up-to-date. What if they come into contact with someone else carrying rubella because they believe that “whether or not I get vaccinated is strictly a personal decision that doesn’t affect anyone else”? I hope that you clearly see that suddenly this is not simply a personal decision. The unvaccinated individual has significantly increased the risk of someone else being born with a serious birth defect – or perhaps even caused the baby to not be born at all. That’s not personal. That’s social.

I realize that I’m not going to sway anyone’s opinion on whether or not they or their children should be vaccinated. (Especially if their belief is based on religious reasons.) However, I just want to make people aware. This really is not just a personal question, and it makes my blood boil, both as a scientist and an expectant mother, when people suggest that it is.

Incidentally, for everyone who’s reading this – have you been vaccinated against MMR?

The intelligent octopus

I wrote about giant squid recently, which prompted thoughts on a related topic in my head. I’ve read before that octopus are really intelligent creatures. But I’ve never actually investigated that claim very closely; I’ve just taken it at face value. So I wondered – is it true? How smart are octopus, anyways? And how do we know how smart they are? Is there a little octopus IQ test given to all eight-legged water-dwellers currently residing in aquariums around the world?

Remember, an octopus is a kind of cephalopod. Cephalopods are classified by bilateral body symmetry, prominent heads, and a variation on a mollusk foot called a muscular hydrostat – aka arms or tentacles. (FYI, a muscular hydrostat is a piece of anatomy found in any animal that has muscle but no skeletal support and that is used to move stuff – such as food – around. Your tongue is a perfect example of one.) There are two major types of cephalopods – those with a mollusk shell (like the nautilus) and those without (like squid and octopus). The octopus takes being shell-less even one step further than many of its relatives, however, because it has no skeletal support at all. It doesn’t even have any vestiges of an internal shell or bones, unlike cuttlefish or squid. Its body is entirely soft.

You’d probably agree that an octopus does, indeed, have a noticeably large head. And housed within that head is a very large and complex brain. In terms of brain size relative to body mass, octopus brains rank higher than those of reptiles and fish. And while their brains are organized very differently from that of vertebrates, there is no denying that it is highly differentiated and organized into different sensory processing centers. So that brings us to the question of how intelligent these creatures are. If they have such large brains relative to their body size, it would make sense that they would be intelligent, right?

The answer is – maybe. It depends on whom you ask. Some scientists believe that the size of the octopus brain is not a sign of intelligence at all, but merely an indication that their entire brains are not built very efficiently. And there may be some backing for that. In fact, octopus have been discovered with spines lodged in their brains, from where a meal that they were eating went the wrong way through their system and got wedged in their heads. That’s a pretty good indication that there is something a little screwy about the way their digestive and nervous systems intersect.

However, others believe that octopus have large brains because they are intelligent. When they say “intelligent,” what they really mean is capable of highly complex behaviors above and beyond simple survival skills. Here are some examples of the evidence that scientists falling in to this camp cite as backing for their belief.

1. Captive octopi are extremely good escape artists. Lids of tanks must be heavily weight shut, or the creatures will use their arms to push their way out. Even then, the areas around octopi tanks are frequently carpeted instead of tiled. That’s because octopi can manage to squeeze through incredibly small spaces (remember, they have no bones). So even with a heavily weighted lid, they still sneak out. But they can’t crawl across a carpeted floor, so they have nowhere to go but back where they came from. When they do manage to escape, where do they go, you might wonder? Usually, they are found in neighboring tanks, snacking on whatever tasty treats they find there.

2. Octopi are highly adept at changing their appearance. They can change the color and texture of their skin at will to match their surroundings. Their appearance can change from solid colors to lightly speckled to dramatically striped very rapidly during hunting, courtship, male-to-male aggression and in response to a threat. They accomplish this through the stretching of chromatophores, which are multicelled organs consisting of pigment sacs and various colors. When their muscles fibers contract and expand, the chromatophores change within seconds, making the octopus much faster at changing appearance than any land-based camouflage artist.

3. Researchers have trained octopi to recognize shapes, colors and textures in much the same way that they would teach vertebrates like rats. In the 1950s and 1960s, scientists at the University of Cambridge taught young octopi how to recognize small and large squares, horizontal and vertical stripes, and black and white circles. And the octopi were quick learners, too, though it seems like their maximum level of knowledge is ultimately below that achieved by rats.

4. Octopi are highly skilled navigators underwater, and have been trained to run through mazes just like mice and rats. When presented with a new underwater terrain filled with holes, an octopus can quickly learn to navigate through the correct holes to get to its den (and a treat). And once it’s figured the route out, it is much faster at navigating it the second time through.

5. Octopi have been shown to be able to solve the “food in a container” challenge. If given a closed jar with a crab inside (crabs being a very tasty octopus snack), most octopi will figure out how to open the jar and get their treat, even if they’ve never seen such a jar before. Incidentally, this is a classic test of problem-solving ability in vertebrates such as non-human primates.)

6. There was even one study in 1992 claiming to show that octopi could learn by observing other octopi. According to the study, an octopus was allowed to observe another octopus being trained to prefer one color ball (red) to another (white). Later, the observer octopus showed a preference for red balls, even though he had not received the training himself. This study has been met with much skepticism, however, and it is generally agreed that it must be rigorously repeated before it can be taken at face value. To date, no one else has been able to reproduce the results under more rigorously controlled conditions, so the jury is still out on that question.

This debate rages on even now, as scientists try to come up with the perfect experimental set-up to test whether the octopus is really intelligent, or simply very good at navigating in its surroundings. Regardless, I love watching octopi at aquariums. Whether or not they are as smart as some claim, they are fascinating creatures nonetheless. I’ve never seen one in the wild, though I’ve often looked (while scuba diving). Who knows – maybe some day I’ll get lucky enough to see one in the ocean!

Why don’t they go bad?

This post is for anyone who’s ever ordered coffee at a restaurant and wondered about the little cups of creamer that they bring with it. These creamers hold maybe a tablespoon full of cream that tastes actually tastes pretty decent in your average cup of coffee, but they also have an inherent mystery about them that has always puzzled me a bit. You see, unlike regular milk or cream, these little things do not need to be refrigerated. Says so right on the lid – no refrigeration necessary. And yet, if you look at the ingredients, there is actual milk in there. So why doesn’t it go bad?

To answer this question, let’s first look at how regular milk is processed for sale in the US. Milk (as well milk-related products like cream and non-dairy products like juice) undergoes a process called pasteurization before it is put on the market. Pasteurization is a process by which any liquid is heated to destroy any microorganisms in it, such as bacteria and mold. It’s named after Louis Pasteur, a famous French scientist who accomplished many things over the course of his life, including advancing the idea that diseases are caused by germs and for developing a vaccine for rabies. He also figured out that heating liquids to a temperature below their boiling point would significantly extend their shelf life (the amount of time before the liquid spoils). There are 2 major methods for pasteurization in use today – High Temperature/Short Time (HTST) and Extended Shelf Life (ESL) treatments. These different methods just use different machinery to achieve the same end. Pasteurization is different from sterilization, in that it is not designed to kill all of the microorganisms within the liquid. Instead, it results in a logarithmic reduction in their levels, reducing them to a point where they are unlikely to cause disease as long as the product is refrigerated. However, as anyone who has ever left a carton of milk in the fridge for too long knows, even a pasteurized product will go bad eventually. That’s because there are still some microorganisms left in the liquid that will cause it to curdle, sour, or otherwise go bad after enough time. If you were to leave the milk out at room temperature, the residual bacteria would spoil the milk even faster – even as fast as overnight.

So if they contain real dairy, why don’t those little creamer packages go bad when left out overnight, too? Well, it turns out that those things undergo a slightly different process called ultrapasteurization. This is also known as ultrahigh-temperature pasteurization, or UHT. Ultrapasteurization is really a process of sterilization instead of pasteurization. When a product is ultrapasteurized, it is heated hotter than in regular pasteurization. This results in the killing of all microorganisms within it – they simply can’t survive the heat. And without any microorganisms, the liquid simply won’t go bad – at least not for a very long time. You can keep ultrapasteurized dairy at room temperature for months if it has not been opened, and it will still be as good when you open it as when it was first produced. Of course, once it is opened, then you need to refrigerate it. That’s because there are numerous bacteria and mold spores floating around in the air, covering your skin, and on every surface in the world. So when that package is opened, those little beasties can get inside and work their destructive magic.

So there you have it. You don’t need to refrigerate little packets of creamer because they have been sterilized. Just another example of science making a difference in little aspects of life you may never have realized!

How to see the inner man (or woman)

There is a major event happening in the life of my family right now, and I haven’t written about it yet but have been waiting for the opportunity. My husband and I are expecting our first child! There are so many things that I’ve thought about writing with respect to the science of pregnancy – what causes morning sickness, how amazing the pattern of development of the human body really is, how statistically unlikely it was that we would have twins (though lots and lots of people teased us about the possibility), and how much I hope our child grows up loving science as much as we do. But I held off, waiting for the perfect topic. And today, I think I’ve found it – I want to write about ultrasounds.

Actually, I’d like to write about some of the various ways that medicine has come up with to look at what’s going on inside the human body – short of surgery, that is. Three big techniques come to my mind, and I’d like to take a few minutes to discuss what each one does, how they are different from each other, and what their advantages are. These three are ultrasounds, x-rays, and MRIs.

I’ll start with the ultrasound (particularly near and dear to us at the moment). The word “ultrasound” actually means sound waves that are above the range of human hearing (20,000 hertz), so when we talk about ultrasounds in a medical sense, we are actually talking about ultrasonography. Ultrasonography has been around for about 50 years, and is extremely widely used in diagnostic procedures to visualize soft tissues, muscles, tendons, and some internal organs (including the heart, liver, gallbladder, kidneys and bladder). It is also commonly used to look at a developing fetus within a mother’s uterus. During the process, ultrasound waves are produced by a small wand, or transducer, which radiate out into the body to focus at the specified depth. This sound wave is partially reflected from the layers between different tissues – specifically, where there is a change in tissue density. The sound waves that get bounced back towards the transducer are detected by a sensitive microphone, which are then translated into an image on a computer screen. There are several big advantages to using sonography as a diagnostic tool. For one thing, it does not use ionizing radiation (as do x-rays), making it safe to use for developing babies. For another, it is relatively cheap compared to its high-power brothers like the MRI. However, it is limited in its ability to see certain structures within the body – it is not good at visualizing bones or the brain, for example.

So let’s go now to the next imaging technique on my list – the x-ray. The medical use of x-rays manipulates the physical properties of – you got it – x-rays. (Clever, huh?) An x-ray is a high energy type of light wave. The energy of a light wave can be measured by its wavelength – the shorter the wavelength, the higher the energy the wave has. In the visible spectrum, red light has lower energy (and longer wavelengths) and blue light has higher energy (and shorter wavelengths). Past the visible spectrum comes ultraviolet light, followed by x-rays. While visible light does not have enough energy to pass through your skin, x-rays have considerably more energy, and thus can pass right through your skin and muscle. However, they are not strong enough to pass through bone. So when you undergo a medical x-ray (for example, to see whether you’ve broken a bone or when you are at the dentist), the doctor will put you in front of an x-ray emitter, which sends x-rays through your body and picked up by a detector (usually a piece of film) on the other side of you. Places of your body where the x-rays pass through (eg muscles and soft tissue) show up as black, while pieces of your body where the x-rays were absorbed (eg bone and teeth) show up white. The film is developed, and the doctor can tell whether your bones are all as they should be – whole and unbroken (hopefully). X-rays are more powerful than sonograms, especially for diagnosing problems specific to the skeleton. However, their major drawback is that they use ionizing radiation in the process. Too much ionizing radiation can cause all kinds of problems for your cells and tissues; however, the exposure any of us will be likely to receive from medical x-rays over the course of our lives is minimal and of low risk.

What about the fancier techniques, like MRI? MRI stands for magnetic resonance imaging, and it uses an entirely different basic principle to visualize the interior of the human body. Instead of sonography (which uses sound) or x-rays (which uses high-energy light), MRIs use magnetic fields. When a person is subjected to an MRI, their body is immersed in a strong magnetic field, which has an effect on the hydrogen atoms throughout their body. The human body can be upwards of 75% water; in each molecule of water, there are 2 hydrogen atoms. Thus, the amount of hydrogen in your body from water alone is really high. And these hydrogen ions will all align with the magnetic field when you are in the MRI machine. So you sit there, with all your hydrogens aligned, and then your body is pulsed with a radio wave. This pushes some of the hydrogen atoms out of alignment with the magnetic field. The radio wave stops, and the hydrogens all slowly snap back into alignment. However, depending on what tissue they happen to be sitting in, they will snap back into place at different speeds. And the speed at which the hydrogens align themselves with is detected by the machine, then calculated to determine what tissue is what. An MRI is a very powerful technique, and can be used to diagnose a number of different medical conditions, including multiple sclerosis, brain tumors, torn ligaments, spinal hernias, tendonitis, and even strokes in the early stages. Another advantage is that they, like sonograms, do not use any form of ionizing radiation. And yet another advantage is that MRIs can be used to look at any plane of the human body – sideways, top-to-bottom, or any other way you can think of. There are some disadvantages, though. Certain people cannot receive MRIs, because the strong magnetic field would be dangerous for them (for example, people with pacemakers). MRIs take a very long time to do, as well, and they are extremely expensive – much more so than either x-rays or a sonogram.

All three of these techniques are powerful in their own right. They can be used to look at different parts of the body – soft tissue, organs, bones or ligaments – with different resolutions. Each one uses a different major method of visualization – magnetic fields, sound waves or electromagnetic radiation. Each one has different costs, risks and benefits. And all in all, I’m glad to live in a day and age where all three are used as a part of everyday medicine. Each one is so much safer than having to cut the body open to see what’s going on inside!

Oh, and by the way, we have had our ultrasound to check on our developing baby. All looks good – 2 arms, 2 legs, and all pieces where they should be! Now we just have to wait to see the little one in person!

The giant of the deep

As you might have guessed from my various postings through the months, I like to write about animals. There are so many things about them that I find interesting – the purring of cats, lizards whose appearance hasn’t changed in a million years, goats that randomly fall over when they are startled, how kangaroos can’t walk backwards, and how, ounce for ounce, bats are one of the longest living mammals on earth. Well, today I’d like to talk about an animal that no one knows very much about, but one that I have found fascinating ever since I first heard about it. This creature is one of the great animal mysteries of the world – we know that it exists, but short of that, we know relatively little about it at all. The animal in question – Architeuthis. The giant squid.

What is a giant squid? Since it is not very creatively named, you’ve probably guessed that it’s simply a really, really big squid. But how big is it? How does it get so big? Where does it live? And why do we know so little about it?

First, let’s discuss squid and octopus in general. Your basic squid has a few standard anatomical features – 8 arms and 2 tentacles, each with hooks and/or suckers, a head (with a very large brain), a mantle (or torso), and 2 fins at the rear of the mantle. Your basic octopus is the same, except that it doesn’t usually have fins, and it’s arms and tentacles only have suckers, not hooks. (There are a few species of octopus with fins, however; they live off the coast of New Zealand and are considered primitive relative to other octopus. That’s why they are referred to as “Dumbo octopus.”) The tentacles of squid are generally much longer than the arms. In fact, there are 2 ways to measure the length of a squid. You can either measure the standard length, which is the length from fins to the end of the arms, or total length, which is the length of the fins to the tentacles. Most squid are quite small, reaching an average total length of almost 2 feet. Of course, that’s the size of most squid – except for the giant squid.

How big a giant squid can get is a matter of debate, since they are so hard to find. The largest reported giant squid ever found washed up in New Zealand in 1887, supposedly at a total length of 55 feet. However, since it was dead, it is likely that its tentacles became stretched like rubber bands once it died and washed up. Based on the length of its mantle, it is now believed to have been only around 30 feet long. Scientists now generally base their estimates of how big a giant squid can get on the remnants of them found in the stomachs of their only known predators, sperm whales. Based on these leftovers, it is now believed that they can reach up to 45 feet in total length. The only invertebrate believed to be larger than the giant squid, actually, is its cousin, the colossal squid (which may be twice as long).

Giant squid live in the depths of every ocean in the world. They are usually found near continental and island slopes of the North Atlantic, the South Atlantic, and New Zealand and Australia, and are rarely seen in tropical waters or near the poles. Unfortunately for scientists, they are often studied after they’ve died, whether they’ve washed up on a beach or are taken out in pieces from a sperm whale’s stomach. In 2004, however, major news was made when scientists off the coast of Japan filmed a live giant squid for the first time ever in its natural habitat. Finding live giant squid in the ocean is notoriously difficult. Scientists usually try to follow sperm whales in the hopes of finding one, but that has proved relatively fruitless. Unless we come up with a better way of finding these elusive giants, they might remain a mystery for some time to come.

Of course, just because we don’t know a lot about them scientifically hasn’t stopped us from using our imaginations to envision them. Giant squid have been a source of legend for thousands of years. Tales of them have been around among mariners since ancient times. In fact, it is believed that the giant squid probably gave rise to the legend of the kraken - a giant sea monster off the coast of Norway and Iceland that was capable of engulfing entire ships (and one that you might remember from the recent Hollywood blockbuster “Pirates of the Caribbean 2: Dead Man’s Chest").

I don’t know why I find these creatures so intriguing, to be honest. Perhaps it’s simply because of their mystery. Imagine – an enormous creature, swimming in the depths of the ocean, so well adapted to its environment that we can’t even find it. Something so large that it only has one predator it needs to fear. And something that, unlike sharks, has not successfully been made into the villain of a Hollywood movie plot such that we feel the need to hunt it down and kill it. Maybe someday we’ll know more about this giant animal. Until then, I must say that I kind of like the uncertainty.