Prepare to get sucked in: Black Holes

What are Black Holes?

In general a black hole is a region of space where the gravity is so high that the fabric of space and time has curved back on itself, taking the exit doors with it. If one wanted to escape the gravitational pull of a planet it must leave the planet's surface with a certain velocity, this is called the escape velocity. On Earth this value is about 25,000 mph. With a black hole the escape velocity is greater than the velocity of light, and since nothing travels faster than light, no object can escape its pull. Research by the American physicist John A. Wheeler helped to predict what a black hole would do to its surroundings. The exact boundary between where light can and can't escape has been termed the "event horizon." Conventionally the size of a black hole is determined by the size of the event horizon, which is a clean quantity to measure and calculate. Everything within the event horizon is collapsed to an infinitesimal point at the center of a black hole. This point is known as a singularity.
( Picture above from: http://wopat.uchicago.edu/Blackhole.jpg)

How a Black Hole is Formed:
The way that black holes are formed is related to the life cycle of a star, so this will be discussed first. Stars are formed when a large amount of gas (mostly hydrogen) starts to collapse in on themselves due to gravity. As it collapses the gas molecules collide more and more and heat up. Eventually the gases become so hot that instead of bouncing off one another they will instead fuse and the hydrogen atoms become helium atoms. All of this additional heat increases the pressure of the gas until it's sufficient to balance the gravitational attraction, and the gas stops contracting. However, eventually a star runs out of its hydrogen and other nuclear fuels. More massive stars will run out of fuels sooner because they need to be hotter in order to balance the gravitational attraction. When a star runs out of fuel it will begin to cool down and thus contract. As the star contracts the gravitational field at its surface gets stronger and its light cones get bent inward more. Eventually, when the star shrinks to a certain radius the gravitational field becomes so strong that the light cones are bent inward and light can no longer escape. According to the theory of relativity, nothing can travel faster than light, so if light cannot escape, neither can anything else, this gives us the region known as a black hole. However, a black hole doesn't form at the end of the life cycle of every star. If that were true then there would be many more black holes which would change a lot of things about our galaxy. In order for a black hole to be formed a star must achieve a critical radius, known as the Schwarzschild radius. This is the radius at which the escape velocity from the star is equal to the speed of light and can be calculated from the formula R_S = 2GM/c² . In this formula G is Newton's gravitational constant, M is the mass of the star, and c is the speed of light. Since G and c are constants it can be seen that the determining factor of whether or not a star becomes a black hole is its mass. If a star doesn't form a black hole then it will turn into either a neutron star or a black dwarf star.

Does a Black Hole Ever "Die"?
There are a few theories that try to describe this complicated process. Stephen Hawking hypothesized that due to quantum-mechanical effects black holes emit radiation. This energy emitted comes from the mass of the black hole. Therefore as energy gets emitted the mass of the black hole will decrease. Over time the black hole will radiate more and more intensely and lose mass faster and faster until theoretically it vanishes. This idea is very speculative because in order to calculate exactly what happens requires quantum-field-theoretic calculations in curved space time. This is not only very difficult to do, but it is also nearly impossible to test experimentally. One look at why black holes evaporate is that according to the uncertainty principle of quantum mechanics it's possible for the law of conservation of energy to be briefly violated. This means that the universe will be able to produce mass and energy from nothing, but only if they disappear soon after their creation. One such example is called a vacuum fluctuation. This is when pairs of particles and antiparticles appear out of nowhere, but soon annihilate one another. Surprisingly, it has been confirmed that vacuum fluctuations actually do exist. If this fluctuation occurred near the event horizon of a black hole and one particle was sucked in, but the other wasn't then the other particle would appear to be emitted. As these particles get emitted continuously over time they appear as radiation given off. This yields a similar result to that of Stephen Hawking's hypothesis in that black holes are constantly emitting radiation and his saying that "Black holes ain't so black."
(Picture above from http://www.centauri-dreams.org/wp-content/uploads/2006/07/hidden_black_hole.jpg)

Types of Black Holes:
Black holes all look different from one another, but this is mainly due to the difference in their surroundings. All black holes are identical except for three major characteristics: mass, spin, and electric charge. Black holes erase all other properties of the objects that they swallow. The mass of a black hole is determined by studying the material surrounding them. There have been three categories established for different size black holes; stellar-mass, which is 5-100 times more massive than our sun, midmass, which 500-1000 times more massive than our sun, and supermassive which could be a million times more massive than our sun or even more. Black holes can rotate about an axis, but there is a limit to their rotational speed. A rotating, uncharged, black hole is described by the Kerr soultion to Einstein's equation for the gravitational field. This equation calculates a maximum angular momentum for the black hole. This formula is given as: J_max <>2G/c. With this angular momentum a maximum angular speed can be calculated. However spatial extent must be considered in these calculations because most stars have a majority of their mass concentrated at their centers. These calculations are very difficult and won't be covered in this blog because of their complexity.

(Video above from http://www.youtube.com/watch?v=CXUBe_H_O7A)

How do we know they exist?

If black holes consume everything within the region of their gravitational pull then how is it possible to
locate these objects? Also if no light escapes a black hole then how could one be seen? In order to answer these questions we must try to observe black holes in an indirect manner. One place black holes are usually found is at the center of a galaxy, such as the one found at the center our galaxy Sagittarius A*. Black holes are usually discovered by satellites that measure X-ray radiation. As matter falls closer and closer to the event horizon it gets hotter and hotter, emitting more heat. This heat gives off large amounts of X-ray radiation. Satellites today such as the Chandra satellite are able to detect these X-rays given off by the objects circling the event horizon.

(Picture above from: http://chandra.harvard.edu/ photo/2008/bhslm/bhslm.jpg)

Other Sources:
http://hubblesite.org/explore_astronomy/black_holes/home.html

http://cosmology.berkeley.edu/Education/BHfaq.html

Hawking, Stephen W. The Illustrated A Brief History of Time. New York: Bantam, 1996.

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The Apple and The Pear

The Apple versus The Pear
Which is the Better Body Type?

It is common knowledge that every person is unique and everyone has a slightly different body shape that is determined by ones genetics. However, there are two main body types that are very common, the apple and the pear, and these shapes also give insight into how a person should eat, exercise and what health problems they are at risk of developing. This is because it is not only important to pay attention to how much excess fat a person has, but to also pay attention to where the fat is distributed on the body because that is more indicative of the person’s health (Apple and Pear Body Shapes).

The Apple:

(Top left picture:www.umm.edu/graphics/images/en/198181.jpg, Top right picture: www.nutrifitness-nyc.com/photos/apple%20tape%20measure.jpg )

A person with an apple body shape gains and stores body fat around their middle section, primarily above the belt in the belly area. When fat builds up in the abdomen and waist area, this is called visceral fat because the fat is surrounding the heart, liver, lungs, kidneys and intestines. This type of fat is very dangerous because it causes inflammation, and produces hormones that make a person more vulnerable to heart disease, cancer and diabetes. Apple shaped people are also more likely to have anxiety, depression, and high blood pressure problems. In general, people with apple shapes are at a higher risk for more serious weight related problems because the visceral fat they store in the abdomen is worse than the fat people with pear body shapes store.
However, it is possible for an overweight apple person to become a healthy apple by reducing the fat around the stomach. A person can reduce their chances of getting the weight related diseases 50% just by losing two inches off their abdomen region. The best way for apple people to loose weight is to eat fiber filled foods, do aerobic exercise and to make sure blood sugar and fat levels are normal. Fiber foods will help to slow down the digestion of sugars and they will lower insulin and cholesterol levels. The ideal diet for an apple person would include 50% complex carbohydrates (veggies, brown rice), 35% “good” proteins (fish, beans) and up to 15% “good” fats (nuts, yogurt). An apple person can never change their body shape, but they can control how much fat is around their stomach and they can work hard, through dieting and exercise, to stay a healthy apple (CBS NEWS).

The Pear:

(Picture below: www.gettherightfit.co.uk/images/17801.jpg)
A person with a pear shaped body gains and stores body fat below the waist in the hips and thighs area. Pear shaped people store subcutaneous fat, meaning the fat is stored right under the layer of skin and does not surround any organs. Subcutaneous fat is stored for energy use when the body needs it. Pear shaped people are more likely to get osteoporosis, varicose veins, and have cellulite and eating disorders. The varicose veins are caused by the compression of the veins by the added weight in the hips and thigh area. Pear shaped people also have less androgen, which is a bone strengthening hormone, than apple people, and this is why they are more susceptible to osteoporosis. In general, the weight related
issues associated with the pear shape are less dangerous than those of the apple shape, but pears are more prone to self-esteem issues due to a poor body image (CBS NEWS).
There are ways; however, that a pear person can control the amount of fat they store and help decrease their chances of getting varicose veins or cellulite. Someone with a pear body shape should eat low fat foods, do resistance training, and continually check to make sure their bone density levels are ok. The pear body shape will to store excess fat in the hips and thigh region, so the less fat the person consumes, the less fat there is available to be stored. Resistance training is also important to strengthen the bones and create more muscle. The ideal diet for a pear person is 55% complex carbohydrates, 30% “good” proteins, and up to 15% “good” fats. It is important to constantly watch ones fat consumption, because a pear person could become an apple person over time if he or she gains weight.

How to Determine Body Shape


The easiest way to determine body shape is to calculate ones waist to
hip (WHR) ratio. The waist to hip ratio is a measurement of the fat
distribution in the body. First, using a cloth tape measure, measure
the circumference of the waist at its smallest part, usually around the
navel. Then measure the circumference of the hips at their widest part.
Then divide the waist measurement by the hip measurement to get the
waist to hip ratio. For a woman, if their ratio is less than or equal to
0.8 this means they have a pear shape. If their ratio is greater than 0.8
this means they are apple shaped. For men, if their ratio is less than or
equal to 1.0 they are pear shaped, but the ratio is greater than 1.0 they
are an apple shape. By knowing what body type one is and learning
the best way to eat and exercise for that type, everyone can be a
healthy fruit (Your Body Shape Reveals Your Metabolism). (Picture above to the right: www.brainiyweightloss.com/images/ApplesAndPears.gif )

References:
“Are You A Pear or an Apple?” CBS NEWS. 28, Feb. 2005. Online. www.cbsnews.com/stories/2005/02/28/earlyshow/health/shapeup.com
“Your Body Shape Reveals Your Metabolism”. Online. www.totalhealthdynamics.com/bodyshap.htm
“Apple and Pears: Body-Shape Weight Loss Made Easy” Online. www.brainyweightloss.com/apples-and-pears.html
“Apple & Pear” Body Shapes”. Online. www.annecollins.com/obesity/apple-shape-pear.htm

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The Power of the Sun

Recent advancements may increase solar cell efficiency

The demand for energy in the US is rising much faster than the projected increase in domestic energy production. The Energy Information Administration forecasts that the US energy demand will grow almost 50 percent by 2030. In order to meet these demands, the electric utility industry is expected to invest $750 billion in power plants, environmental technology, and transmission and distribution lines (“Annual Energy Outlook 2008”). Already, according to the EPA, the average American family spends $1900 per year on energy bills (“Fall 2006 Energy Star News”). Clearly, energy is an important part of everyday life. However, energy use is also affecting the environment in which we live and so alternative sources must be found. One potential alternative source is solar energy.

Solar energy is a renewable energy source since it is continuously provided by the sun. It is also beneficial because it produces no emissions, almost no solid waste, and produces no long term damages to the land. The two major categories of solar energy technology are photovoltaic and solar-thermal (“Non-Hydroelectric Renewable Energy”).

Photovoltaic cells are made up of semiconductors, usually silicon. When light hits the cell, a certain portion of its energy is transferred to the semiconductor material, which knocks electrons loose and allows them to flow freely. The PV cell has an electric field that forces all of the electrons to flow in one direction, producing a current that in turn produces power. For example, those solar cells found in calculators are PV cells (Aldous, 2000).

(For an interactive PV cell animation see:
http://nanosense.org/activities/cleanenergy/solarcellanimation.html)

Video: Solar Energy Panels - How They Work

On the other hand, solar-thermal technologies concentrate the sun’s energy using mirrors or other reflective devices to heat a liquid and create steam that is used to turn a generator and create electricity (“Non-Hydroelectric Renewable Energy”). Many solar-thermal devices are used to heat swimming pools.

New technological advances are increasing the efficiency of solar cells and therefore further increasing the potential of solar energy. Researchers have just recently produced an anti-reflective coating that not only improves the efficiency of the cell but also allows sunlight to be absorbed from almost any angle. The coating was created by scientists from the Future Chips Constellation at Rensselaer Polytechnic Institute using nanotechnology. To put things into perspective, a normal silicon solar cell absorbs just over two thirds of sunlight while a solar cell treated with the anti-reflective coating absorbs 96.21 percent. The coating is comprised of seven tiny layers made of silicon dioxide and titanium dioxide. The series of layers helps to “bend” the flow of light, capturing more sunlight than before. The coating can be applied to almost any photovoltaic material. Finally, solar cells are usually placed in locations facing south in order to collect the most sunlight for a longer part of the day. However, with this new technology, solar cells may be placed in varying locations (Knight, 2008).


Nevertheless, there are a few possible caveats of the new coating. The tiny layers can be fragile and more effort needs to be put into making them stronger. Others say that the coating will only produce four or five percent more power than regular solar cells. Finally, the solar cell coating has not been produced in bulk and so it is still unknown how successful it will be (Knight, 2008).

References

Aldous, Scott. "How Solar Cells Work." 01 April 2000. HowStuffWorks.com.

“Annual Energy Outlook 2008”. June 2008. Energy Information Administration.
< http://www.eia.doe.gov/oiaf/forecasting.html >

“Fall 2006 Energy Star News”. Energy Star.
< c="news.nr_fall2006">

Knight, Matthew. “New nano coating boosts solar efficiency”. 12 November 2008. CNN. <http://www.cnn.com/2008/TECH/science/11/12/solar.coating/index.html?iref=newssearch>

“Non-Hydroelectric Renewable Energy”. 28 December 2007. U.S. Environmental Protection Agency. < http://www.epa.gov/cleanenergy/energy-and-you/affect/non-hydro.html#solar>

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A House Made of Soybeans?

With the realization that many non-renewable resources are running low, thinking “green” has taken the country by storm. And construction companies are doing just that, by building houses with materials composed of little "green" edamame. The soybean, or edamame in Japanese, is a popular food in a number of countries, including increasingly the United States, thanks to its health benefits (high protein, omega-3’s, etc). But this legume is also the perfect food for creating sustainable buildings, and in more way than one (United Soybean Board). (photo to left: rows of soybean plants. http://www.nysaes.cornell.edu/pp/pp419/PP419Gallery/abawi/pages/healthy%20soybeans.htm photo to right: an edamame pod. http://www.dow.com/renuva/contact/ ).

The latest advance in green construction is soybean insulation. Unlike the traditional polyurethane types which are composed of over 90% petroleum or petroleum derivatives, soybean insulation is composed of renewable soybean oil, reducing the dependence on fossil fuels (Pandolfi, 2008). In addition, U.S. companies that install soybean insulation make it from soybeans grown right here in the country, eliminating the wasteful energy and materials usually spent on packaging and shipping for products made overseas (BioBased Insulation). Some companies that install this sustainable insulation even use water as their blowing agent, as opposed to harmful chemicals like CFCs or HCFCs which break down the ozone layer (Pandolfi, 2008). Since soybean insulation is more durable and resistant and creates an air-tight seal, unlike traditional insulation, it more efficiently keeps a building cool or warm (BioBased Insulation). This in turn reduces the amount of energy (and money!) spent on air-conditioning or heating.

Watch a video of soybean insulation being installed in a green building. Scroll to the bottom of the page and click on "Heifer International" to the left. (BioBased Insulation).

Soybean insulation also has health benefits. It contains no urea or formaldehyde, the synthetically made compounds used to hold together normal insulation, which have been shown by the National Cancer Institute to be carcinogenic to humans (National Cancer Institute). This green insulation is resistant to mold growth and other allergens, and is not a source of food for any rodents or insects (BioBased Insulation).

But the use of an edamame in construction does not end there. One company, Emega Technologies, has created a soybean oil based polyol which can be used as a building plastic or as building blocks when used in conjunction with steel reinforcement. Not only is this a renewable form of plastic, unlike fossil fuel based types, but it reduces the amount of timber needed for a house’s frame (Duffy). (photo to right: soy ICF building. http://www.emegabuild.com/building.php )









There are other innovations that are using soybeans in place of petroleum, which is the traditional material from which common building materials are made. This includes soybean polyol-based carpet backing - a trend spreading especially in hotel and condominium chains - soy adhesives in plywood and particleboard panels, soy-based resins in non-VOC paints and paint removers, countertops composed of recycled newspaper bound by soy-based resins, and soybean oil construction lubricants. All of these products are eco-friendly, as they are made of renewable resources and are biodegradable (Delta Farm Press, 2008 and Pandolfi, 2008). (photo to left: soy-based carpet, paint, plywood, countertop, and lubricant. http://img2.timeinc.net/toh/i/a/0808-soy-products/soy-products-00.jpg ).





So the next time you eat an edamame, think of all the things that little bean can do!










Pictures

1. http://www.nysaes.cornell.edu/pp/pp419/PP419Gallery/abawi/pages/healthy%20soybeans.htm




2. http://www.dow.com/renuva/contact/




3. http://www.emegabuild.com/building.php




4. http://img2.timeinc.net/toh/i/a/0808-soy-products/soy-products-00.jpg

Sources

1. United Soybean Board. http://www.soybean.org/




2. Pandolif, Keith. “So You Pumped Your Walls Full of Soybeans?.” This Old House Magazine. July/August 2008.




3. BioBased Insulation. 2007-2008. http://www.biobased.net/




4. National Cancer Institute. http://www.cancer.gov/




5. Duffy, Don. Emega Technologies. 2007. http://www.emegabuild.com/building.php




6. Delta Farm Press. “Soybeans Under the Carpet.” January 2008. http://deltafarmpress.com/

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Green Tea: The Miracle Tea?

There has been a great deal of hype about green tea lately. It’s on the news, all over the internet and it’s even made multiple appearances on Oprah. So are the claims true? Can it help you lose weight, lower your cholesterol or even prevent cancer? The jury is still out, but there is no denying that green tea does have the potential to improve your health.

The History of Green Tea
Archeological evidence suggests that people have been drinking tea in one form or another for 500,000 years. India and China were the first countries to purposefully cultivate tea, and green tea has been used medicinally in China for at least 4,000 years(www.umm.edu). The Chinese have used green tea to treat common aliments like headaches as well as more serious conditions like depression (Parkinson 2008). Green tea has also been used in India and China as a diuretic, astringent, and blood sugar regulator. Today, hundreds of millions of people around the world drink tea, and there is increasing research into the medicinal properties of green tea.

What makes Green Tea Special?
Green tea is made from the same plant (Camellia sinensis) as black and oolong tea, but it is steamed rather than fermented (http://www.umm.edu/). Unfermented tea leaves contain high levels of polyphenols, specifically epigallocatechin gallate or EGCG (Parkinson 2008). EGCG is an antioxidant, a chemical which degrades free radicals. Free radicals are particles which have the potential to alter DNA and cause cell death. Over time, free radicals can lead to cancer, heart disease and other health problems. Antioxidants help to neutralize free radicals, and therefore may help prevent certain diseases (www.umm.edu).

Research
In 1997, The University of Kansas found that EGCG is twice as powerful as resveratrol, the antioxidant found in red wine. The researchers hypothesized that the high consumption of green tea in Japan may explain why the rate of heart disease in men there is very low, despite that fact that seventy-five percent of Japanese men are smokers (Parkinson 2008). Animal research has also shown that the antioxidants in green tea inhibit the absorption of cholesterol and promote its excretion from the body. While these and other studies would indicate that green tea may help prevent heart disease, the FDA has concluded that there is not yet enough research to support this claim (http://www.umm.edu/).
In 1994, the Journal of the National Cancer Institute published a population study of Chinese men and women which indicated that drinking green tea reduces the risk of esophageal cancer. Along these same lines, the University of Purdue has shown that a compound in green tea actually inhibits the growth of cancer cells (Parkinson 2008).
Green tea may even aid in weight loss. It was found that men given caffeine and green tea extract burned more calories than those given caffeine and a placebo (Parkinson 2008).

The Bottom Line
The FDA has yet to back any of the claims that green tea can help prevent heart disease, cancer or any of the other many diseases researchers are considering. However, it can be said there are decidedly few negative side effects associated with drinking green tea. The only side effect reported to date is insomnia due to the caffeine in the tea. Then again, green tea has about 40-70% less caffeine than coffee (Parkinson 2008). It may take some time before researchers and the FDA reach any conclusions about the health benefits of green tea. In the meantime, I think I’ll brew myself a cup!

References
Parkinson, Rhonda. "The Miracle of Green Tea." About.com. 2008. 18 Nov 2008 .

"Green Tea." Complementary Medicine. Sept 30 2008. University of Maryland Medical Center. 18 Nov 2008 .
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CSI: Fact vs Fiction

So which is it? CSI? CSI Miami? CSI NY? Everyone has a favorite, and these days more than 50 million people are tuning in each week to watch at least one of the three CSI series (“The Real CSI,” 2005). They have increased the popularity of forensic science across the globe, but exactly how accurate is the CSI world compared to real life?

It seems that even the writers and producers, paired with their forensic science advisors, have failed to catch a few key mistakes in many episodes of CSI. Testimony from real crime scene investigators (CSIs) about their experiences on the job can help dissolve the myths and expose the reality of forensic science for CSIs in real-world crime labs. It’s not as beautiful as it looks on TV.

(Picture 1: http://blogosfere1.blogs.com/photos/uncategorized/csi.jpg)

The following is a few forensic myths that CSI episodes contain:

Myth #1: DNA tests are quick and always pinpoint the right criminal
- DNA tests can sometimes take weeks or months to get results, and depending on the quantity and quality of the sample, an exact match may not be possible.

Myth #2: CSIs carry guns, interrogate suspects at the crime scene, and sometimes make arrests
- CSIs that work as civilian workers (and are not actual police officers) are usually not allowed to carry guns
- CSIs only question suspects once the detectives have already interrogated them
- CSIs cannot arrest people because they are not actual police officers; however, under certain circumstances, CSIs can make “civilian arrests,” but these occur much less often than portrayed on TV

Myth #3: CSIs have extensive, sweeping knowledge about everything in forensic science
- No! The majority of CSIs specialize in a specific sub-discipline and rarely know extensive knowledge about all other types of forensic science within the field
- Most often, CSIs will work in groups to take advantage of different specializations, since one CSI usually does not possess all of the knowledge necessary to solve a single investigation

Myth #4: All crime labs have state-of-the-art equipment
- In reality, crime labs are often limited by their funding and maintain only a limited collection of equipment and machinery

Myth #5: Fingerprints can be identified quickly and accurately using a computer program
- Fingerprint matches require nine points of identification for a positive match and can fail if no distinguishing marks on the print can be found
- Analyses often require human fingerprint examiners to make the final comparison and identification of suspects, not just a computer match
- The national fingerprint database, AFIS, takes longer to search its files than depicted on the TV show (more than just a few minutes!), and AFIS only contains fingerprints of existing criminals, often decreasing the chance of finding a positive match

Myth #6: CSIs dress in expensive designer outfits to investigate the crime scene
- Although CSI’s often wear street clothes instead of an actual uniform, they are unlikely to wear high heels and designer clothes to a crime scene!

After recognizing the misconceptions portrayed by the TV shows from the CSI series, it is important that people recognize the limitations of forensic science in the real world. Despite its growing popularity for students (there are record levels of enrollment at the National Forensic Academy) and the glamorous CSI lifestyles portrayed on TV, we must remember that “real CSI investigations still involve a great deal of time, luck, and guesswork” (“The Real CSI,” 2005). But there aren’t nine seasons for nothing! People love CSI, no matter how unrealistic it can be. After all, it is only a TV show.

Sources:
Cratty, Carol, & Arena, Kelli. “FBI gives glimpse inside real ‘CSI,’” CNN.com, 2008. http://www.cnn.com/2008/CRIME/07/14/fbi.lab/index.html
“CSI Factual ‘Inaccuracies,’” 2002, http://www.angelfire.com/jazz/jboze3131/csifacts.htm
“Investigators: The Real CSI,” CBSNews, July 25, 2003. http://www.cbsnews.com/stories/2002/10/25/48hours/main526983.shtml
“The Real CSI,” CNN.com, May 16, 2005. http://www.cnn.com/2005/LAW/05/05/murder.overview/

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Top Ten Medical Advancements of the 20th Century

Top Ten Medical Advancements of the 20th Century

#10: Placebo controlled, randomized, blinded clinical trials

One of the first accounts of a clinical trial is from 1747 when a naval surgeon James Lind tested the effects of various remedies for scurvy and compared them to each other. Since then clinical studies have been gradually improved, either by adding control groups or making the study “blind,” that is the subject are unaware of which sample (experimental or placebo) they are receiving. Not until the 20th century, however, did scientists and doctors begin running clinical trials that were placebo control, randomized, and double blinded, where both the subjects and the experimenters don’t know which sample is being administered. These trials are far more accurate and revealing than most clinical trials of the 18th and 19th centuries because of the elimination of bias. This leap forward in our ability to research has helped create many life-saving drugs and treatments. 1

#9: Development of vitamin supplements

While vitamins were known to have existed before the 20th century, the only sources of vitamins were certain types of food. This is a problem for groups of people who live in conditions which limit the variety of the food they can eat. For example, crews on a ship would routinely develop scurvy due to Vitamin C deficiency. This was caused by a lack of fruit aboard the ship on especially long journeys. The British began bringing lemons and limes aboard on such journeys (hence the nickname “Limeys,”) and saw a decrease in the cases of scurvy at sea.

(Photo at left: Symptoms of scury from 2)

Another example of when change in diet was implemented to increase the ingestion of certain vitamins was in the Japanese Navy, where (during the 1880’s) low ranking sailors often only ate white rice regularly. This bland low-meat diet led to the development of beriberi, a condition described as severe lethargy caused by thiamine (Vitamin B1) deficiency. The Japanese realized this and changed the rations allotted to their sailors, drastically reducing the cases of beriberi among them.

Better understanding of vitamins and their role in human health can greatly reduce the occurrence of certain diseases, as demonstrated above. But in both cases new foods were required in order to fight the disease. What came about in the 20th century were vitamin supplements, the ability to concentrate certain vitamins into pill form. Vitamin supplements are a great tool in the fight against malnutrition and hunger worldwide. They do not spoil like most foods do, and they are mostly inexpensive to produce. While some people may only have white rice to eat, these debilitating diseases can still be prevented. 3

#8: Development and use of X-Rays

In 1895, Wilhelm Röntgen was experimenting with a new type of ray which he referred to as “X.” Little did he know that those rays would improve the lives and livelihoods of millions of people in the future. Röntgen discovered the medical application of X-rays when he photographed his wife’s hand, creating the first image of a human body part made by X-rays. The early tubes used to create the rays were very inefficient, but around 1920 a more efficient vacuum tube was invented, making way for wide spread use of X-rays for medical purposes. Today they are used to identify diseases mainly in bone, but also in soft tissue (pneumonia, lung cancer, kidney stones, etc.). 4

#7: Development of medical insulin for diabetics

Insulin was first isolated at the University of Toronto by Dr. Fredrick Banting 5. It had been known that the pancreas was involved in the disease diabetes since the late 19th century, but not until 1921 was it discovered that the hormone insulin could be used to treat type 1 diabetes. Until then such a diagnosis meant death for the patient. Banting and Charles H. Best made their patent on insulin available to all who could produce it in order to avoid prohibiting any production of this life-saving drug in any part of the world. That decision and their work have saved millions of lives all over the world and will save many more in the future. 6

(Photo at left: The Bronco’s quaterback Jay Cutler was diagnosed with Type 1 diabetes. Image from 7)


#6: Advancements in heart surgery.

Surgeons didn’t begin operating on the heart until the late 1800’s, and at that time success rates were very low. One of the first surgeons to operate on the heart had a 60% mortality rate after operating on over 100 patients. However, this was considered amazing by the standards of the time, since without the procedure they all would have probably died. These few successes led the way into the 20th century, where many new advances in heart treatment and surgery allowed people to live longer and fuller lives. Some of these advances include bypass surgery, heart transplants, and pacemakers. 8

#5: Development of immunosuppressive drugs and tissue typing.

When undergoing organ transplant, a patient’s tissue must be matched with the tissue of prospective donors in order to ensure the new tissue will not be rejected by the patient’s immune system. This problem may have prevented many transplant procedures from being studied, but the development of better tissue typing procedures made it possible to find appropriate donors faster and more accurately 9. Immunosuppressive drugs are also very important, since they further prevent the immune system from attacking new tissue, which sometimes happens even with close matches. The combination of these two methods has allowed many people to receive the new organs they need to survive without many complications. 10

#4: Advances in cancer treatment.

Chemotherapy – This treatment method arose from research into alternative uses of mustard gas during WWII. Doctors administered the drug intravenously to cancer patients and noted a temporary improvement in their condition. Since then research has found many forms of successful cancer treatment involving chemicals. 11

Radiotherapy – With the discovery of X-rays also came the discovery of a new but mysterious cancer treatment. Establishment of radiotherapy began in the early 20th century, and gradually improved through the years. CT scans improved the efficiency and effectiveness of radiotherapy dramatically in the 1970’s. 12

(Photo at right: A patient receiving radiotherapy treatment. Image from 13)

Immunotherapy – Our own immune systems are very powerful, and can be used through immunotherapy to combat cancer. In the 1920’s it was found that certain vaccines stimulate the immune system in such a way that it can fight certain types of cancer, depending on what vaccine is used. 14

These three cancer treatments have proved life saving for many cancer patients. The combination of two or all three of them often proves to be successful in putting cancer either into remission or killing it outright.

#3: Advances in blood typing, banking, and transfusion.

Blood transfusion had been experimented with in both humans and animals since the 15th century, many attempts being fatal for both patient and donor. Distinct blood types were first noticed in the 19th century. But both these techniques were not adequately improved for wide-scale use until the early 20th century, when a method of blood banking was established. Separating the plasma from the blood cells allowed for longer storage time and reduced occurrence of reactions. These improvements in blood typing, banking, and transfusion technology save millions of lives in the U.S. alone every year, as 15 million units of blood are transfused annually. 15

#2: The development of antibiotics.

Antibiotics are a very important part of modern medicine. Anti-bacterial soap prevents the spread of bacterial disease, antibiotics turn would-be dangerous infections into a small rash that goes away in about a week, and post-operative infections are minimal due to sterilizing efforts in operating rooms at hospitals and in doctors’ offices. All of these benefits stem from the discovery of Penicillin by Alexander Fleming in the early 20th century. Since then, medical research into the antibacterial effects of certain compounds and substances has led to the ability to prevent most bacterial infection in both everyday life and in the hospital setting, and in the case where an infection does occur the proper antibiotic medicine can be used to combat the infection. 16

#1: Eradication of smallpox and vaccines for various diseases (polio, diptheria, tetanus, measles, mumps, rubella, chickenpox, flu, Hep. A & B)

Smallpox was a very deadly disease, one that killed millions upon millions of people worldwide throughout history. The first cases of it are thought to have been from near the beginning of history, about 10,000 BC in Egypt, Africa, and the Middle East. The disease had been prevalent in most of the world, spreading through trade, war, and migration. Spanish conquistadors spread the disease to the Americas, where millions were killed in several severe epidemics within the Aztec and Incan empires. People struggled for a cure or treatment, and eventually developed a treatment via inoculation in the 17th and 18th centuries. This, however, came with a risk of developing the actual disease rather than becoming immune. It wasn’t until Edward Jenner began vaccinating patients with cowpox about the turn of the 18th century that a safe and effective method of preventing smallpox was developed 17.

(Photo at left: A timeline of events leading to the erradication of smallpox. Image from 18 )

In the early to mid 20th century, the United States had successfully eradicated smallpox within its own borders. The last naturally occurring case in the U.S. was in 1949. This achievement led the World Health Organization to realize the eradication of smallpox was a real possibility worldwide. Through vigorous vaccination programs put on by the WHO and many nations independently, the last naturally occurring case of smallpox in the world occurred in 1977 in Somalia. Vaccinations save many lives and have improved life expectancy world wide dramatically. Combined with the lives saved by the eradication of smallpox, the development of safe and reliable vaccines has greatly improved human health in ways no one could have imagined previously. For this reason, it is #1 on our list of the top ten medical advances of the 20th century. 19


References

1. "Placebo." Wikipedia, The Free Encyclopedia. 20 Nov 2008, 11:29 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Placebo&oldid=252966512.
2. http://www.med.uc.edu/departme/cellbiol/ecm.htm (photo)
3. "Vitamin." Wikipedia, The Free Encyclopedia. 20 Nov 2008, 17:35 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Vitamin&oldid=253015897.
4. "X-ray." Wikipedia, The Free Encyclopedia. 20 Nov 2008, 21:34 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=X-ray&oldid=253061324.
5. "The Discovery of Insulin - The History of Diabetes Treatment." Inventors. 20 Nov 2008 http://inventors.about.com/library/inventors/bldiabetes.htm.
6. "A brief history of diabetes and insulin." Diabetes Information and Statistics. 16 May 2006. 20 Nov 2008 http://www.isletsofhope.com/diabetes/information/history_1.html.
7. www.pnfl.org/2008/04/ (photo)
8. Stephenson, Larry. "History of Cardiac Surgery." Cardiac Surgery in the Adult. 20 Nov 2008 http://cardiacsurgery.ctsnetbooks.org/cgi/content/full/2/2003/3?ck=nck.
9. Velickovic, Zlatibor. "Brief history of Human Leukocyte Antigens - discovery and characterisation." 20 Nov 2008 http://www.tissuetyping.org.au/nswttWeb/hla_history.html.
10. "Immunosuppressive drug." Wikipedia, The Free Encyclopedia. 9 Nov 2008, 09:01 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Immunosuppressive_drug&oldid=250616376.
11. "Chemotherapy." Wikipedia, The Free Encyclopedia. 20 Nov 2008, 22:38 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Chemotherapy&oldid=253073532.
12. "Radiation therapy." Wikipedia, The Free Encyclopedia. 20 Nov 2008, 13:42 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Radiation_therapy&oldid=252979606.
13.http://www.iaea.org/NewsCenter/Features/Radiotherapy/Images/Gallery/pages/012.shtml (photo)
14. Park, John . "Immunotherapy Cancer Treatment." Cancer Supportive Care Programs National and International. 20 Nov 2008 http://www.cancersupportivecare.com/immunotherapy.html.
15. "Blood transfusion." Wikipedia, The Free Encyclopedia. 18 Nov 2008, 13:30 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Blood_transfusion&oldid=252564366.
16. "Penicillin." Wikipedia, The Free Encyclopedia. 20 Nov 2008, 01:53 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Penicillin&oldid=252905973.
17. Riedel, Stefan. "Edward Jenner and the history of smallpox and vaccination." 20 Nov 2008 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1200696.
18. http://encarta.msn.com/media_701508643/smallpox_through_history.html (photo)
19. "Vaccination schedule." Wikipedia, The Free Encyclopedia. 16 Oct 2008, 23:20 UTC. 21 Nov 2008 http://en.wikipedia.org/w/index.php?title=Vaccination_schedule&oldid=245777192.

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Reliability of an Indoor Time Trial Using the Velotron Electronic Bicycle Ergometer Without the Use of a Pacer

Study done by: Leanne Heede, Joe Hickson, E.E. Noreen

Intro:

• Historically, it has been challenging to replicate endurance performance measured in a laboratory setting. One common solution has been an indoor time trial (TT) using the subjects’ bicycle placed onto a trainer, which applies resistance to the rear wheel. A TT is the completion of a given distance in the least amount of time. This traditional method presents technical complications and does not provide the subjects with any external motivational stimuli. Despite these drawbacks this method has shown good test-retest reliability (1-4).

• The Velotron Pro bicycle ergometer uses virtual 3D interactive software that simulates a virtual cyclist riding outdoors. The subjects’ power output (watts) is used by the software to determine instantaneous speed of the computer simulated cyclist. The software provides the option of using a pacer to give the subject a virtual cyclist to race against. As a result of the software, the Velotron Pro provides the rider with continuous feedback that is not available using a standard trainer. The Velotron Pro is a fully adjusted bicycle ergometer that uses an electronic brake as opposed to a bike placed on a roller system which relies on friction between the tire and roller. This removes one of the common technical problems seen with the traditional method used for indoor TTs.

• Unlike TT that did not use a pacer which either found no improvement over time or an improvement from TT1-TT2 and not TT2-TT3 (1-4), a previous study from this lab using the Velotron Pro with a pacer suggested an improvement in TT performance with each subsequent trial.

Our goal of this study was to determine the test-retest reliability of three consecutive repeated indoor time trials using the Velotron Pro bicycle ergometer without any pacer.

We performed the study using seven trained competitive cyclists (ages 39 +/- 10 years). We performed three time trials on an 8 mile course which was at a 4% incline. Each trial was completed within 2-7 days under the same standard conditions. On the fourth visit, the cyclists body compositing was assessed using the Bodpod and the cyclists VO2 ma

x was measured using a metabolic cart.

The subjects performed a routine 15 minute warmup which was the same each time. The velotron ergometer was calibrated according to the instructions. For each time tiral that was performed, the finishing time, average watts, average heart rate, and average RPMs were recorded. The data that we recorded was analyzed using a repeated measures ANOVA, CV, ICC, and SEM.

Table 1 shows the averages for the data that was recorded during each time trial. Table 2 shows the reliability of the testing that we performed. This helped us determine is the cyclists improved over each trial along with other things. Graph 1 shows the differences in time between the three different trials that were performed.

The data that we obtained from this study shows that there was almost a significant difference between the first and second time trials. The difference between the second and third time trials were not significant. This can be seen in Table 2. This data suggests that removing a pacer decreases the liklihood of continual improvement with each consecutive trial performed. By looking at Table 2, we can suggest that the pacer may unfluence the finishing time while having little or no effect on the test-retest reliability. This is consistent with other studies that have been performed.

Conclusion:

1. Jensen K. and Johansen L. Reproducibility and Validity of Physiological Parameters Measured in Cyclists Riding on Racing Bikes Placed on a Stationary Magnetic Brake. Scand J Med Sci Sports 8: 1-6, 1998.
2. Palmer G.S., Dennis S.C., Noakes T.D., and Hawley J.A. Assessment of the Reproducibility of Performance Testing on an Air-Braked Cycle Ergometer. Int J Sports Med 17: 293-298, 1996.
3. Smith M.F., Davidson R.C., Balmer J., and Bird S.R. Reliability of Mean Power Recorded During Indoor and Outdoor Self-Paced 40 km Cycling Time-Trials. Int J Sports Med 22: 270-274, 2001.
4. Sporer, B.C. and D.C. McKenzie. Reproducibility of a Laboratory Based 20-km Time Trial Evaluation in Competitive Cyclists Using
5. Bike Picture: www.racemateinc.com
6. Rider Picture: www.dearbornhealth.com
   

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Top Ten Roller Coasters: What makes them great?

(Above photo of Boulder Dash)

Top Five Wooden Roller Coasters

1. Boulder Dash
Boulder Dash is located in Bristol, CT at the Lake Compounce Park. It's built into the side of a mountain and speeds through trees making it one of the top roller coasters in the world.
2. El Toro
This coaster is located in Jackson, NJ at Six Flags Great Adventure. Riders of El Toro experience an adrenaline rush and a smooth ride.
3. Raven
Santa Claus, IN houses this ride in the Holiday World Park. This roller coaster proves that size and length aren't everything because it generates sensations of weightlessness and incredible speeds in just 90-seconds.
4. GhostRider
This ride can be found in Buena Park, CA at Knott’s Berry Farm Park. It was built by the same company that built Boulder Dash. Defying friction, GhostRider doesn't come to a stop until the brakes are applied.
5. Cyclone
Astroland in Coney Island in Brooklyn, NY is home to the Cyclone. This coaster may not have the smoothest ride of all, but it is a favorite because it is one of the originals.






(Below photo of Superman: Ride of Steel)
Top Five Steel Roller Coasters

1. Superman: Ride of Steel
Six Flags New England in Agawam, MA is home to this amazing coaster. Superman gives riders the perfect combination of great speed and airtime from the moment it leaves the station until it returns.
2. Apollo’s Chariot
This coaster is located at Busch Gardens Europe in Williamsburg, VA. This is one of the smoothest and most exhilarating roller coasters in the world.
3. The Incredible Hulk
Islands of Adventure at Universal Studios in Orlando, FL is home to this great ride. It is a roller coaster unlike any other, but it must be ridden to be believed say the experts.
4. SheiKra and Griffon
SheiKra is located in Busch Gardens Africa in Tampa, FL and Griffon in Busch Gardens Europe in Williamsburg, VA. Because they are both diving and floorless coasters they are tied for number four. They are the most unique and wildest roller coasters on the planet.
5. Nitro
Six Flags Great Adventure in Jackson, NJ is home to this coaster. The creators of Apollo’s Chariot also created this coaster, which is smooth and has incredible airtime.

(Photo to right of GhostRider)

Energy

Roller coaster trains do not have engines or motors. They rely on stored potential energy to give their riders an amazing experience. Slowly pulling the train up the initial hill of a roller coaster is not just a way to scare the passengers, it is a way to build up potential energy that will turn into kinetic energy on the way down. As it moves higher and higher up the potential energy is increasing. The potential energy that has been stored up on the way up can be released as kinetic energy on the way down the hill. At the top of the first hill there is maximum potential energy. Kinetic energy increases less very little potential energy at the bottom of the first hill. The second hill of the coaster is much smaller and the kinetic energy allows for the movement of the coaster up this hill. While moving up this hill potential energy is being built up. While going down the second hill the potential energy is converted back into kinetic energy to propel the car down the hill. The reason for the decrease in the height of the hills while moving along is because some of the mechanical energy is lost as thermal energy due to friction with the tracks. When entering a loop, the train has a lot of kinetic energy and very little potential energy. When it reaches the top of the loop the amount of kinetic energy is smaller than the amount of kinetic energy at the bottom of the loop. The change from potential to kinetic energy is what the roller coaster experience is all about. When the train reaches the end of the track the remaining mechanical energy is dissipated using breaks bringing the cars to a stop. All the energy is converted to heat as the brakes are applied. Energy is conserved throughout the ride but mechanical energy is lost throughout the ride because of the friction with the tracks.

(Photo to right of El Toro)


Forces
The force of gravity acts on you at all times, wherever you are on Earth. It pulls you towards the ground, but the sensation of weight is the force of the ground pushing up against our feet. Gravity plays a large role in the movement of roller coasters. If there is a hill that the coaster needs to go down gravity will pull it down and if there is a hill it needs to go up gravity will apply a downward force on the back of the car to cause deceleration. The other force that we feel is the normal force. This normal force acts on you at all times, on Earth and while riding a roller coaster. On a roller coaster you often accelerate and the magnitude of this force changes creating the feeling of weightlessness. The other force that we feel is centripetal force. When going around curves, the centripetal force is pointing towards the center of the curve and it is supplied by the side of the car that you are sitting in. Newtown's first law that says you will stay in motion explains why the car applies a force on you while on the roller coaster. The force is needed to keep you following a circular path. When we are riding at constant speed we only feel the force of gravity, but as we speed up or slow down we get pressed up against our seats or the restraining bar in front of us. Because of Newton’s first law of motion, “an object in motion tends to stay in motion,” says that we will continue to move at the same speed and direction unless another force acts on us. The force that speeds us up is the force that our seats push against our bodies and the force that slows us down is the force that our restraining bar pushes against our body. Force and gravity play a large part in the movement of roller coasters. Physics is what makes roller coasters work!

(Photo of SheiKra)

Levine, Arthur. "Best Roller Coasters." About.com. 2008. 9 Nov 2008 http://themeparks.about.com/cs/coasterbooks/a/bestcoasters.htm.


Harris, Tom. "How Roller Coasters Work." How Stuff Works. 2008. 9 Nov 2008 http://science.howstuffworks.com/roller-coaster.htm.
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