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The folks at NASA set up a few streaming video cameras in the International Space Station, so you can watch a video of the Earth as viewed from Space in real time as the station orbits around the Earth (click on the picture below). You can also check the map to see where in its orbit the station is. If it's in the dark side of the Earth the screen will be black. If it's changing from one camera to the other the screen will be gray momentarily. If you watch long enough you will be able to see the Earth light up or get dark as the station goes from sunrise to sunset and back! If you want to see more about space, check one of my old posts about gravity that features astronaut Chris Hadfield playing a version of David Bowie’s Space Oddity in the space station! ***
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What is the most abundant cell type in our bodies? The surprising answer is: bacteria. Bacteria in our gut outnumber the cells in our bodies by a ten to one ratio. Although we don’t normally think about bacteria as forming part of our bodies, our physiology and biochemistry is inextricably intertwined with these denizens of our bowels, and the extent of this relationship is just beginning to be untraveled. It is known that bacteria can affect our bodies by producing certain chemicals that cause a variety of effects on the immune system and on organs like the intestine or the liver. But what is not well known is whether bacteria can also affect our brains. For example, researchers found out that when they fed mice antibiotics this caused a change in their behavior. These antibiotic-fed mice exhibited an increase in their exploratory activities and certain changes in their brain chemistry. When the researcher fed the antibiotics to the same strain of mice bred in sterile conditions (i.e. no bacteria in their guts), the behavior of the mice did not change and they experienced no alteration in brain chemistry. This indicated that the changes in gut bacteria brought about by the antibiotics were responsible for the alteration of the behavior of the mice. Another group of researchers performed an experiment where they fed groups of mice high-fat diets. The scientist treated some of the high-fat diet fed mice with a probiotic. This is a preparation of selected strains of bacteria thought to be beneficial for the intestine. Prolonged treatment with probiotics leads to a change in the bacterial makeup of the gut. The probiotic treatment prevented the mice from becoming obese, and the researchers found that this was associated with a decrease in food intake and an increase in certain blood hormones associated with the induction of satiety. When the scientists analyzed the brain of the probiotic-treated mice they found changes in the levels of expression of genes associated with the reduction of hunger and the increase in satiety. Of course these are animal experiments, but there are several conditions in humans involving changes in gut bacteria such as irritable bowel syndrome that are accompanied by feelings of anxiety and depression, and certain psychiatric conditions are also believed to be affected by the makeup of the bacteria of the gut. So next time you experience some mood swings during a bout of intestinal distress, take a good look at the remnants of your last meal as they disappear down the toilet. They may be related to what you are thinking or feeling more than you care to know! Image of gut bacteria by Janice Carr, Centers for Disease Control and Prevention. *** If you like this blog you can have links to new blog posts delivered to your e-mail address. Please click here. A hieroglyphic on a wall of the Temple of Luxor in Egypt reads: Man, know thyself and thou shalt know the Gods. This maxim, often shortened to “know thyself,” is a recurring motif in philosophical thought. The idea behind this teaching refers to knowledge about our inner selves, and gaining that knowledge is often a lifelong process requiring much effort and sacrifice. However, technological advances have made it possible for individuals to effortlessly gain a type of vital knowledge about themselves that was not contemplated by ancient philosophers: the knowledge contained in the genes. Ancestry is one aspect of the knowledge that can be glimpsed from sequencing the genes of a person. Unlike most molecules in nature, the molecules of DNA contained in our cells are historical documents. They contain information about who our ancestors were, and combined with other information can reveal to us where we came from. Nowadays there are several companies that offer to sequence your genes and provide this kind of information. But the most important information that the genes can reveal to an individual is about that person’s health. In the years following the completion of the human genome project, scientists have gained a tremendous amount of knowledge about the effects of genes on the risk of acquiring certain diseases. A recent high visibility example of what this knowledge can be used for was when the actress Angelina Jolie decided to undergo a double mastectomy after learning that she has a mutation in a gene called BRCA1 that greatly increases her risk of breast cancer. As with ancestry, there are several companies that offer their services to sequence genes and provide individuals with information on how their genetic makeup can affect their health. For example, you can learn if you have defective genes that could make treatment with certain drugs fatal or if you have certain genes that can increase your chance of suffering conditions like stroke or diabetes. This genetic information can also be used by doctors to tailor the treatment patients will receive and has the potential to usher in a new era in personalized medicine. However, genetic knowledge can be a double-edged sword. There are some diseases for which there is no cure. In those cases a positive result for a defective gene will basically tell individuals how and approximately when they will die, which is not the knowledge most people may want to have. Additionally, genetic information has the potential to be used by insurance companies to calculate the risks of insuring a given individual and charge higher premiums or refuse coverage. And what about finding a mate? Do you have the right to know the genetic information of the person you want to marry? What if you found out that the person you love and wish to marry has a genetic makeup that when combined with your own will produce a child with a severe disease? Also, what if governments or institutions with racial or ethnic agendas use this information in troublesome ways? Imagine the likes of a Hitler having access to the genetic information of every single individual in the country. Accessibility to genetic knowledge raises as many questions as it answers. Currently, sequencing part of a person’s genome to derive ancestry or some health information is affordable, but sequencing the full complement of genes costs several thousand dollars and is outside the reach of the average person. However, technological advancements are reducing sequencing times and making the process cheaper. It is conceivable that within a decade not only will full genetic information be accessible to the average person, but it may even be part of the routine tests that are applied when babies are born. What will we do with that information? Where will it be stored? Who will read it? Perhaps the Egyptian who carved that maxim in the temple of Luxor had a point. Should we first know ourselves before we know our genes? Photo credits: Double Helix: Jun Seita / Foter.com / CC BY-NC Temple of Luxor: dorena-wm / Foter.com / CC BY-ND *** If you like this blog you can have links to new blog posts delivered to your e-mail address. Please click here. Astronaut Chris Hadfield recorded a fantastic version of David Bowie’s Space Oddity while circling the Earth in the International Space Station. While I like the music and the views of the Earth from space, this video got me thinking about a very common mistake that people make when they see videos of objects or people floating inside the space station. This is the notion that this happens because there is no gravity. The confusion is further exacerbated because this situation is often referred to as “zero g.” In today’s blog we will see why this is not the case.
To understand what is going on in space let’s do a thought experiment. Imagine that you are standing on top of a high diving platform holding a pencil. As you jump from the platform you let go of the pencil and for a few seconds before you hit the water the pencil will appear to “float” next to you. Is the pencil in this situation experiencing no gravity? Of course not, the pencil is falling alongside you. Now consider this. Suppose in the instant you jump and let go of the pencil a room magically materializes around you in such a way that you are not in contact with any of its surfaces. This room is falling at the same speed you and the pencil are falling, but the room has a camera in a corner pointed towards you. During those few seconds before the room and you hit the water, the camera will record you and the pencil apparently floating in the middle of the room. An observer who watches the camera footage of those few seconds migt conclude that you and the pencil are floating impervious to gravity, but this is not true: you are falling. This situation is identical to what you see in the video of Chris’s guitar spinning in space and him floating next to it. Chris and his guitar inside the International Space Station are no more floating or impervious to gravity than you and the pencil would be inside that hypothetical room. The reason astronauts appear to float is that (as in the example of the room) they are falling towards the Earth along with the space station around them. But if this is true, why doesn’t the space station crash and burn? The reason is that even though it is falling towards Earth, the space station is moving at the right speed parallel to Earth’s surface. If the surface of the Earth were flat the space station would eventually hit the ground. However, because the Earth is round it curves as the station falls, and the speed of the station is carefully controlled to maintain this balance. As a result of this the space station maintains a roughly constant distance from the Earth’s surface even though it is falling towards it. “Here am I floating round my tin can Far above the Moon Planet Earth is blue And there's nothing left to do.” So you see, in the realm of the space station gravity is alive and well. Contrary to the song’s lyrics, the space station and its singing astronaut are not “floating,” they are falling towards Earth, but their speed and direction is such that they never reach the ground. *** If you like this blog you can have links to new blog posts delivered to your e-mail address. Please click here. I just read about a cool experiment that you can do at home. You can follow the link, but in a nutshell the experiment involves cutting a piece of cheese into cubes of different sizes. When you place these cheese cubes in a conventional preheated oven you find that the smaller cheese cubes melt first. However, if you place these cheese cubes in a microwave oven it is the larger cubes that melt first! How can this be? The explanation has to do with something called the surface to volume ratio. If you calculate the surface area of a cube and divide this by the volume of that cube, you will find that the smaller cubes have a greater surface to volume ratio than the larger cubes. So when you place the cheese cubes in a conventional oven, the heat enters the smaller cubes much faster (because they have more surface area relative to their volumes) than it enters the larger cubes. Most people that have tried to heat food in a conventional oven have experienced this. The center of bulky pieces of food may remain cold while the outside is hot, whereas smaller pieces heat up faster. But just in the same way that heat gets in faster into a small cheese cube that has a high surface to volume ratio, it is also true that heat can get out equally fast (dissipate) from such cubes. The microwave oven generates heat inside the cubes. In the larger cubes the heat has trouble moving out (because of the lower surface to volume ratio) and accumulates, heating the cube and melting it, whereas in the smaller cubes the heat escapes much faster and the cube doesn’t get as hot. The interesting thing is that this principle also applies to living things. Mice have a very high surface to volume ratio compared to a human being, and tend to lose heat very fast just like the small cheese cubes. This is why mice have a very high metabolic rate (expressed on a per body mass basis) to compensate for this large heat loss. If a mouse had the metabolic rate of a human it would die from hypothermia (lack of heat). Conversely if a person had the metabolic rate of a mouse, he/she would die from over-heating because the heat generated in the large volume of the human body would have trouble getting out through the limited surface area, just like in the large cheese cubes. If an elephant had the metabolic rate of a mouse it would (in theory) boil! But even more interesting is that we owe our very existence to the principle of the surface to volume ratio. Compare our planet teeming with life to the barren wasteland that is Mars. The Earth is larger than Mars and therefore has a lower surface to volume ratio and cools slowly (like the large cheese cubes). All the heat that gets trapped inside the Earth as a result of this has melted its core, and the spinning of this core generates a magnetic field. This magnetic field protects the Earth against the solar wind, which would otherwise strip away our atmosphere. Unlike the Earth, Mars is smaller (has a high surface to volume ratio) and, like the small cheese cubes, it has cooled faster. As a result of this, its core solidified and stopped spinning a long time ago. When this happened, Mars lost its magnetic field and its atmosphere was stripped away by the solar wind. So there you have it. Who needs expensive labs or particle accelerators? Here is a fundamental physical principle responsible for life that holds true from mice to planets and that you can put to the test in your kitchen. Isn’t that cool? Now next time you get served cheese cubes and crackers at a cocktail party you can impress everyone by talking about the principle of the surface to volume ratio and heat transfer. Please remember to reference this blog! Mouse & Cheese Photo credit: Darny / Foter.com / CC BY-NC-ND Mars Photo credit: NASA Goddard Photo and Video / Foter.com / CC BY *** If you like this blog you can have links to each week's posts delivered to your e-mail address. Please click here. A follow up to my Pale Blue Dot post during the past holidays. ***
If you like this blog you can have links to each week's posts delivered to your e-mail address. Please click here. I just learned an interesting factoid that I want to share with you. The image below is a picture of the tallest mountain in the world. Do you know which is it? If you answered Mount Everest you are correct. This mountain is over 29,000 feet high and has a lot of name recognition in the world. But let me ask the above question in a different way. When measured from the center of the Earth, which is the tallest mountain in the world? Or alternatively, the summit of which mountain is closer to outer space? Surprisingly the answer is not “Everest” but rather the mountain in the picture below. Do you know its name? This is a volcano in Ecuador called Chimborazo and it is 20,564 feet tall when measured from sea level. However, when measured from the center of the Earth, Chimborazo is 1.35 miles taller than Everest and therefore also closer to outer space! In fact, when measured in this manner, Everest is the fifth highest mountain in the world with the second, third, and fourth positions occupied by the mountains Huascaran in Peru, Cotopaxi also in Ecuador, and Kilimanjaro in Tanzania, respectively.
The reason for this surprising fact is that the Earth is not a perfect sphere. Due to the Earth’s rotation, the land and the sea around the equator bulge outward. Someone standing at sea level on the Earth’s poles is about 13 miles closer to the center of the Earth than someone standing at sea level on the equator. Because Chimborazo is located 1 degree south of the equator it sits on top of this bulge, whereas Everest which is 28 degrees north of the equator is not “pushed up” as much. When I learned about this my first thought was: what about the Death Zone? The Death Zone is found in high mountains above an elevation of 26,000 feet. At this altitude the abundance of oxygen is only 1/3 of that found at sea level and the human body is incapable of adapting effectively. The death zone is one of the reasons Everest is so hard to climb and also why the route to the top in this area of the mountain is littered with the bodies of dead climbers. I reasoned that if Chimborazo is closer to outer space than Everest, then it should also have a death zone. As it turns out this is not the case because the Earth’s atmosphere also bulges out around the equator. As a result of this, the summit of Chimborazo is safely below the death zone and the human body can function in the thin atmosphere of the summit if allowed the time for adaptation to high altitudes. So there you have it. Now next time someone says that Everest is the tallest mountain, you can impress everyone by saying, “Wait a minute…” and proceed to set the record straight. Remember to reference this blog as your source. Thanks! Everest photo credit: Rupert Taylor-Price / Foter.com / CC BY Chimborazo photo credit: apgwhite / Foter.com / CC BY-NC-ND *** If you like this blog you can have links to each week's posts delivered to your e-mail address. Please click here. As another year comes to a close during which we have again experienced the joys and the nightmares of who/what we are as a species, it is apt to remember the vision of the Pale Blue Dot. In 1990 NASA instructed the Voyager 1 space probe, then 3.7 billion miles away from Earth, to take a picture of our world. The picture shows our planet as a minute speck (arrow) in the middle of one of several bands caused by the interaction of sunlight with the camera. The late astronomer Carl Sagan used this picture and its title "Pale Blue Dot" to write an eponymous book in which he put forward one of the greatest calls to reason that have ever been written. It takes an astronomer to look at things from the outside, and remind us of how petty and insignificant our quarrels are, and how tenuous our foothold in the universe is. Below you can see a video and /or read the passage from the book. "From this distant vantage point, the Earth might not seem of any particular interest. But for us, it's different. Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam. The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner. How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity – in all this vastness – there is no hint that help will come from elsewhere to save us from ourselves. The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we've ever known." Carl Sagan (1934-1996) *** If you like this blog you can have links to each week's posts delivered to your e-mail address. Please click here. In the movie "My Fair Lady" the late British actor Stanley Holloway sings the song about taking the easy way out, "With a Little Bit of Luck," in his signature Cockney accent. One of the most memorable lines from the song can be heard in the above video at 4:39 minutes where he sings:
Oh, it's a crime for man to go philandering. And fill his wife's poor heart with grief and doubt. Oh, it's a crime for man to go philandering - but With a little bit of luck, with a little bit of luck, You can see the bloodhound don't find out! Throughout the ages many men, to the dismay of their wives, have furtively escaped the domestic realm seeking the thrill of "the other woman" and hoping for that "little bit of luck." Neither the threats of social humiliation, financial ruin, or the fires of hell have prevented the likes of David Petraeus, Tiger Woods, John Edwards, Bill Clinton and countless other less famous characters from heeding the call of testosterone. Exasperated women over the centuries have wondered whether something can actually be done about these Lotharios. Well ladies, your wait may soon be over. Science may have the answer to your quandary! In recent study published on the Journal of Neuroscience the researchers examined the effect of the hormone oxytocin in modulating social distance between men and women. This hormone along with other related substances has been found to participate in the regulation of the pair bond between males and females in several monogamous species of mammals. In their study the investigators took 2 groups of men, single and married, and tested the effects of an intranasal spray of oxytocin on how close they would stand to an attractive woman. They found that married men when sprayed with the hormone would stand further away from the woman, whereas the hormone had no effect on single men. The researchers also found that married men sprayed with the hormone approached pictures of attractive women more slowly. Of course this research is in its early stages, but it is possible that in the future several lines of sprays enhanced with the right hormones may be available to wives so they can prevent their would-be Casanova husbands from running away after the nearest skirt. What do you say ladies? If this product existed and your better half displayed a tendency to fancy himself Don Juan, would you spray him? Leave a comment and let us know! *** If you like this blog you can have links to each week's posts delivered to your e-mail address. Please click here. Have you ever asked yourselves what makes something funny? Why do we laugh when something is funny? What goes on in our brain when we hear something funny? Why do we seek the funny? Well, as it turns out neuroscientists have been hard at work in this area for a while using the most up to date technologies to answer these questions. One way to study these questions is to look at the areas of the brain that increase in activity while subjects listen to jokes. For this, scientists have used a technique called functional magnetic resonance imaging (fMRI) that can identify those regions of the brain that become more active in response to a stimulus. In a recent study, scientists imaged the brain of volunteers who listened to jokes or non-jokes. The scientists also asked the subjects to complete a questionnaire to rate the level of "funniness" of what they heard. The results indicate that funny is not something that is localized to one structure in the brain. When what the subjects heard was funny, several dispersed structures in the brain were activated. Some of the structures like the amygdala, ventral striatum, and midbrain, are associated with the experience of positive reward. This means that "getting a joke" produces pleasure. The extent to which these areas were activated correlated with the subjective ratings of funniness that the participants ascribed to the jokes. The researchers could tell whether a person thought something was funny just by evaluating the increases in activity in these brain areas. One interesting aspect of this study was the evaluation of jokes with semantic ambiguity. There is an area of the brain called the inferior frontal gyrus (IFG) that increases in activity when subjects are exposed to funny things. The IFG also becomes active when a person encounters semantic ambiguity. For example: "What was the problem with the other coat? It was difficult to put on with the paint roller." This sentence activates your IFG briefly because of the ambiguity associated with the word "coat" (a garment vs. a layer of paint). The IFG is a brain structure involved in resolving ambiguities. Now consider the following joke: "Why don't cannibals eat clowns? Because they taste funny!" When you listen to this joke, your IFG also becomes active in response to the ambiguity regarding the meaning of the word "funny" (odd or bad vs. amusing), but in this case the resolution of the ambiguity is more difficult than with the example about the coat. As a result of this your IFG remains active for a longer time. The authors of the study found that this increased activity of the IFG was an important component associated with the funniness of jokes with semantic ambiguity. This study evaluated the neurological complexity behind something as seemingly mundane as finding a joke funny. Of course, when scientists study these processes they try to simplify things as much as possible to make them amenable to research. One aspect that was not evaluated is whether we find a joke funny when we are the object of the joke. For example if an author received a review of their book that stated: "Your book was both good and original. Unfortunately the part that was good was not original and the part that was original was not good." Would the author find that funny? I can't even begin to imagine how the brain scan would look! What do you think? (Image courtesy of smokedsalmon) *** If you like this blog you can have links to each week's posts delivered to your e-mail address. Please click here. |
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