For those who have wondered, or if you’re just plain curious, click on the link below and use the slider:
http://learn.genetics.utah.edu/content/begin/cells/scale
Very well done!
Dr. Dave
How big is a skin cell or carbon atom?
Posted by drdavescience on November 1, 2009
Posted in Check it out! | Tagged: scale, science | Leave a Comment »
NASA Ares X-1 Success!
Posted by drdavescience on October 28, 2009
The test launch was a success! Way to go NASA!
Watch the test launch below:
Posted in In the News, Space | Leave a Comment »
NASA Test Launch of Ares
Posted by drdavescience on October 28, 2009
Check out NASA TV to see the test launch of the new Ares rocket. How exciting!
Mission Control is waiting on weather; I hope it cooperates! Dr. DavePosted in Uncategorized | Leave a Comment »
Flu from the Flu Shot? Not! Part 1
Posted by drdavescience on October 23, 2009
A few weeks ago I received my annual flu shot. Although I had heard stories about people describing "flu-like" symptoms after vaccination, I had never experienced a problem over the past 10 years. This year was different.
Within hours of the injection my arm was sore; by the end of the day I felt achy, tired and I had a low grade fever. I would say that my symptoms were "flu-like," but if you think about it, many illness that are not the flu often start off with "flu-like" symptoms.
According to the scientific data contained in the vaccine's prescribing information, the symptoms I described are common (read the section on adverse events).
But is it the Flu?
According to the CDC, it takes an average of 2 days from exposure to the flu virus before showing signs of illness. Since the side effects occurred within a few hours of vaccination, it must be something else.
What is it? Stay tuned…
Dr. Dave
Posted in Uncategorized | Leave a Comment »
My Laptop is Alive!
Posted by drdavescience on October 23, 2009
Hello!
My laptop has been given a new lease on life thanks to the kind and knowledgeable folks atwww.powerbookmedic.com. Thank you!
I'm testing a few applications right now and thinking about everyday science concerns. Posts to come soon!
Dr. Dave
Posted in Uncategorized | Leave a Comment »
Computer Failure
Posted by drdavescience on October 16, 2009
My beloved laptop of the past 6 years suffered a catastrophic hard drive failure. Since the other components work great, I’m having the hard drive replaced. (It’s the less expensive options, and in this economy, it’s a wise choice.)
Once I get it up and running, I hope to post more frequently. In the meantime, I’ve been writing my ideas down in a notebook.
Thanks for your patience!
Dr. Dave
Posted in Uncategorized | Leave a Comment »
Malaria originated in chimps!
Posted by drdavescience on August 5, 2009
I came across this article about the origins of malaria in CNN. I have had malaria twice in my life, so stories about this disease always draw my attention.
It should come as no surprise that the chimpanzee is the origin of malaria in man; after all, chimps are our closest genetic relative in the animal kingdom. Before you go blaming the apes for malaria, keep in mind that the spread of disease is not a one-way street; it is very likely that man has also spread disease to apes.
What is malaria?
Malaria is disease that is caused by a parasite and is spread by mosquitoes. Malaria causes fevers, severe headaches, and chills, and if left untreated, it can lead to brain damage and even death.
Mankind has been plagued by malaria for thousands of years. Long ago, silly theories on the origin of diseases were commonplace. People believed that malaria was caused by something foul in the air, which is where the disease got it’s name. (“Mal” means bad and “aria” means air.)
For many centuries, there was no treatment for malaria until the 1600s when an observant Jesuit priest living in ancient Peru noticed local tribesmen using ground bark from cinchona trees to treat the telltale fever and shivering associated with the disease. The bark was soon sent to Rome, where malaria was rampant, and the results were amazing.
In the early 1800s, scientists determine isolated quinine, the ingredient responsible for the anti-malarial effect of the cinchona bark. Many historians believe that quinine played an important role in the colonization of Africa and during World War II.
Where?
Mosquitoes tend to thrive in warm and humid environments, so it’s no surprise that the majority of people affected by the malaria live in countries with a tropical climate. Check out the malaria distribution map from the CDC website:
According to the CDC, 500 million people suffer from malaria and 1 to 3 million people die each year.
Today, very few cases of malaria are reported in the US, but this was not the case 50 years ago when it was the scourge of the south. In fact, malaria was such a significant health problem that it influenced the then newly-formed Centers for Disease Control (CDC) to select Atlanta as its headquarters.
My personal experience
I was 10 years old and traveling in India when I first caught malaria. Usually, travelers in high-risk regions take anti-malaria pills to prevent the disease, but I had to stop due to serious side-effects.
As my friends and family know, I am a mosquito magnet. Frankly, I am not surprised that I caught malaria.
As soon as I fell ill the local doctor immediately recognized the signs of malaria and was able to treat me right away. I was sick for about 1 week, with the worst symptoms lasting only two days. I was lucky because treatment was readily available. People in poor countries do not have rapid access to health care and tend to suffer for long periods of time.
Malaria: Take two
About one year later, I had malaria again; however, this time I was at home in the San Francisco Bay Area, which has a mild climate and very few mosquitoes. How did I catch malaria in the Bay Area? The answer is, I didn’t.
As it turns out, the parasite that causes malaria can live inside liver cells without causing any harm. For some unknown reason, the parasite exits the liver cell and becomes active to cause disease again. This is what happened to me.
My second experience with malaria was considerably worse because my primary care doctor had never seen a patient with the disease. For two weeks I suffered from raging headaches, high fevers and chills. I was rapidly losing weight and I even slipped in and out of consciousness a few times.
My parents were terrified. Eventually I was referred to an infectious disease specialist who recognized the signs of malaria and treated me right away. Given my extreme symptoms, the specialist told my parents that I was lucky to be alive.
Although I did not understand it at the time, I realize that my primary care doctor would never have thought of malaria given the rarity of the disease in America. I can’t blame him, but I hope that he learned from my illness.
Epilogue
My experiences with malaria changed my life. Because of the illness, I decided to major in immunology at U.C. Berkeley and worked in an infectious diseases laboratory for a few years.
Ultimately, the most lasting lesson of my bouts with malaria is that life is very precious. I had come close to losing it, but I was spared. Knowing firsthand what it is like to suffer from malaria, I can only hope that medical science can create a vaccine that can halt the disease in its tracks.
For more information about malaria, please click here for the CDC’s Malaria page.
If you would like to read more about the philanthropic efforts of the Bill and Melinda Gates Foundation to combat malaria worldwide, please click here.
-Dr. Dave
Posted in Health | Leave a Comment »
Healthcare in America
Posted by drdavescience on July 27, 2009
As I do most mornings, I was watching NBC’s Today show as I was getting ready for work this morning. CNBC’s Maria Bartiromo and Matt Lauer were having an interesting exchange on health care economics.
To paraphrase their conversation, Maria and Matt were talking about the cost of a person. Yes folks, they were talking about putting a price on a person. Most people will find it impossible to put a price on a person, especially a loved one. After all, life is priceless.
But what if your business depended on putting a price on a person? Health insurance companies are in the business of providing affordable health care, therefore they have to put a price on a person to make a profit.
Ultimately, this means a health insurance company must set spending limits on medical care. There are people within health insurance companies that determine whether or not a medical procedure will improve the length or quality of a person’s life. That’s why there are heartbreaking stories about loved ones who are denied expensive medical procedures. It’s sad, but it is business.
Another part of Maria and Matt’s conversation touched on the obesity epidemic in America. About 1 in 3 Americans are overweight or obese. Most cases of obesity can be manged through a healthy diet and regular exercise. Obesity is too significant a problem to ignore when considering that an obese person costs 4-times more to treat than a life-long smoker.
I agree with this statistic. The health effects of smoking manifest later in life, but the health effects of obesity manifest earlier and places greater demands on the health care system.
As a follow-up, Matt presented the following analogy: If a driver crashes a lot, they have to pay higher insurance premiums. Does this mean that a person who does not manage their health, weight, etc. should pay more for their health insurance?
What do you think?
I only ask because a health care package for all Americans is (slowly) winding it’s way through Congress. A comprehensive nationalized health care system has eluded Americans for a long time because it is a complex problem. Solving a complex problem takes time and money. Lots of money. And unfortunately, money comes from taxes.
I think a nationalized health care system is a good idea. All I ask is that people take responsibility for their own health. Stop smoking. Lose weight. Exercise and eat right. This is what Americans can do their for their country and can help drive costs down. It’s not too much to ask.
If that’s not enough motivation, just remember that the French have a good nationalized health care system. If they can do it, so can we! Right?
Dr. Dave
Posted in Health | Tagged: Health and Medicine | Leave a Comment »
How high do fireworks fly?
Posted by drdavescience on July 22, 2009
During a recent fireworks show, a friend had asked me if I knew how high the fireworks fly before it explodes. I didn’t know the answer but I began to wonder how I could figure it out.
Judging the height of an object in the sky is not easy without a reference. Maybe if I knew the height of a nearby building or tree? With a height reference I could probably estimate the height of a firework with some accuracy.
Low clouds can be a helpful indicator of height. I can simply gauge the altitude of the firework relative to the cloud. The altitude of a cloud can be found on weather websites like www.wunderground.com.
But wait, what if there are no clouds or buildings nearby?
I gave this a thought and came up with a way to estimate the height using a grade-school trick and math.
Thunderstorms, the Speed of Light and the Speed of Sound
Lightening and thunder occur during a thunderstorm. Lightening is the discharge of electricity between clouds, from a cloud to the ground, or vice versa. Most people don’t see the actual lightening bolt, but they’ll often see a flash. Thunder is the sound a lightening bolt makes and is often heard after a flash is seen.
In grade school, I learned to tell how far away a lightening strike is by counting the number of seconds between seeing a lightening flash and hearing the sound of thunder. Each second is about 1000 feet (1114 feet to be exact), so if I counted 5 seconds between lightening flash and hearing thunder, then the strike was about 5000 feet away (or about 1 mile).
This trick works because light travels incredibly fast when compared to sound.
What does this have to do with fireworks?
When watching the fireworks show with my friends, I could see the explosion before could hear it. So, just like I do for a thunderstorm, I began counting the number of seconds between the time I saw a firework explode and when I heard the explosion.
Most of fireworks I saw that night had a delay of 2 seconds or less. This corresponds to about 2000 feet. Keep in mind that this does not mean that the fireworks fly 2000 feet high. Take a look at the diagram below:
(Please forgive the quality of the diagrams in this post as I made them while eating lunch at work.)
As you can see from the diagram, I drew a triangle to help me solve the height problem.
Notice that the 2000 feet I estimated using the timing trick corresponds to the distance from me to the fireworks. In geometry speak, this is called the hypotenuse, the longest side of the triangle. You can also see that the other two sides of the triangle corresponds the height and my distance to the launcher, which we don’t know. Now, let’s figure out the height using trigonometry.
Wait…trigonometry!?! That’s a scary word!
Actually, trigonometry is not a scary word once you know what it means. “Trigon” refers to a triangle and “ometry” refers to measuring. Are you afraid of measuring triangles? I didn’t think so.
Several thousand years ago, some clever people figured out how to solve problems like ours using triangles. Even to this day, triangles are used to solve problems in engineering, medicine, architecture and aviation.
How to solve our problem?
When dealing with a triangle, we can use some easy rules of trigonometry to figure out our problem. For instance, there are two useful right triangles (triangles with a 90° angle) that can make problem solving really easy. These two triangles are the 30°-60°-90° right triangle and the 45°-45°-90° right triangle shown below:
In these two types of triangles, the sides exist in a fixed ratio. Always! This means, if you know the length of one side, and an angle, you can figure out the length of the other sides by using the ratios.
Back to the fireworks problem
To figure out the height of the firework, I need to figure out how much I tilted my head to see the fireworks. This will help me figure out which triangle to use. Since this is an estimate, it’s okay to guess. I know I wasn’t craning my neck up or looking straight ahead. I’d guess that I was looking about 30° to 45° up.
Take a look at the diagram below:
If I was looking about 30° up, I would use the 30°-60°-90° right triangle. Using the ratios, a hypotenuse of 2000 feet would correspond to a height of 1000 feet.
If I was looking about 45° up, I would use the 45°-45°-90° right triangle. Using the ratios, a hypotenuse of 2000 feet would correspond to a height of 1414 feet.
Therefore, using the thunderstorm timing trick and trigonometry, I would estimate that fireworks I saw that night flew up to about 1000 to 1500 feet.
Keep in mind that approach is not perfect, that’s why it’s an estimate. An estimate gets us close to the exact answer. There were issues about timing between seeing and hearing the explosion, the angle the firework was launched, as well as effects of the wind.
Even if we had the exact data, we would still use trigonometry to solve the problem.
Enjoy!
Dr. Dave
Posted in How does it work?, Math, Physics, Problem Solving, Uncategorized | Leave a Comment »
Your Oil Dollars at Work!
Posted by drdavescience on June 5, 2009
This post doesn’t have much to do with science. I couldn’t believe what I read and so I had to write write about it.
I had heard a while back that a Saudi prince is purchasing a VIP Airbus A380 Super Jumbo as his private jet. In case you are wondering, the A380 is the largest passenger aircraft (it’s bigger than a 747).
At first I thought it was a joke. The plane is so huge that I could not imagine that somebody would want it for a private jet.
Just recently, I found out that the story is true. Here’s the plan for the proposed interior.
The custom VIP A380 costs $500 million; that’s half a billion dollars! It’ll cost him more to fuel, fly and maintain it. Considering that this same Saudi prince already owns a VIP 747, surely there could be better ways to spend $500 million than to purchase a bigger plane.
How about providing the best health care to his people? What about investing in education and technology so they’ll have something to rely on when their oil supply finally runs out?
Hey, it’s not my money so why should I bother, right? Think about it the next time you’re at the gas pump.
Dr. Dave
Posted in Uncategorized | Leave a Comment »
