Extinction of Carribean Monk Seal
June 9th, 2008 ecoliWe mourn the loss of another marine mammal.
via Brian Switek at Laelaps
a science and medicine related weblog from scienceforums.net
Disease among Brazil’s “Forest People”
June 8th, 2008 ecoliA week or so ago, I posted and commented some pictures released by the BBC on the isolated tribes living in the forests of Brazil.
This is an interesting article from the New York Times that gives an interesting and more complete perspective on the matter than the BBC report did.
I think this is a poignant quote:
If they are removed and survive the exposure to diseases they have never encountered, it is likely that the unique knowledge and beliefs that define them, the spirit of their life, will probably slip away.
It’s pretty much a lose/lose situation. Rapid growth of western culture will eventually and inevitably bring these groups into contact with western diseases. Therefore, they will have to accept western medicine if they hope to survive. It is likely therefore, that they will lose their culture from this, even if it isn’t necessarily in a single generation.
So, assuming that they want to keep their culture in the first place, they are going to have to make some difficult decisions in the near future.
via Gene expression
Favicon Revisited
June 6th, 2008 ecoliA few months ago, I was one of the first to report on Google’s favicon change. In fact, my blog came up as one of the first when doing a search for “New Google Favicon” on Google’s search engine. Now though, it seems as if I have been delegated to page three, as more powerful blogs have picked up the story.
I still would like to report, however, that pachi, of Arbitness has informed me that Google has published an official response about the change:
“We recognized there was a need for a Google icon that would better work across multiple applications including web, mobile and client applications. We felt the small ‘g’ had many of the characteristics that best represent our brand: it’s simple, playful, and unique. We will be looking to improve and enhance this icon as we move forward.“
Or, as pachi says, Google is trying to rebrand itself, especially now that it seems cell phone and mobile technology is entering the web browsing world for good. Though, I don’t think my original hypothesis, is that far off.
Bicycle Physics
June 6th, 2008 ecoliHere’s a question posed by the Scientific Indian regarding bicycle balance. Given my new found love for bike riding (see breaking out the bike) I figured I’d give this one a go.
Here’s the question:
Which is easy: To maintain your balance when cycling uphill, or when cycling downhill? Assume you maintain a constant speed of 6 km/hr and the inclination is constant. If you like to challenge your proficiency in physics, assume further that you are negotiating a bend.
Here’s my answer (feel free to add your own). In terms of balance, it doesn’t make a difference, assuming a constant speed. However, due to a property of physics called torque, the speed it takes to travel uphill and downhill is rarely going to be the same, and that’s due to gravity.
Torque is what causes rotation in the wheels of the bike when you pedal, and is analogous to an angular force. Pushing the pedals creates torque. The pedals are a lever that turns the main cog, which pulls the chain, which cause rotation of the gear, which is attached to the wheel.
Most bicycles today consist of a gear shift that changes the gear ratio depending upon the speed. Different combinations of gears creates a different effect, by controlling the relative size of the front and rear cogs. A high gear ratio should be used on a flat surface, turns the wheel multiple times for each turn of the pedal. When traveling uphill, a lower gear ratio should be used, which results in having to pedal a lot to get the wheel to turn once.
However, what I’ve noticed from my own experience, is that the gears, when traveling uphill, will shift only when the bicyclist starts pedaling faster. If the biker tries to maintain the same pedal speed, the force of gravity will slow you down dramatically, you won’t have enough torque to keep the wheels moving at the same speed, momentum is lost and you lose balance. You have to pedal a lot harder and faster against gravity, so that the gear will shift to maintain speed.
The advantage to this, is that when you’re traveling on a flat surface, it would get tiring to have to pedal 5 times just to turn the wheel once (for example). But, when you’re going uphill, with gravity slowing you down, pedalling faster will help you keep momentum, and prevent falling over. If you tried to bike uphill on a high gear ratio, I suspect, your wheels would try to turn faster and travel than gravity allow, and you would slip backwards or simply tip over.
When traveling downhill, however, you have gravity on your side. The acceleration due to gravity maintaings your speed, without having to put much force into pedalling. Travelling fast, momentum is maintained, sometimes without having to pedal at all, depending on the steepness of the hill. A low gear ratio is maintained simply by virtue of the acceleration due to gravity.
The second part of your question is a simple matter of centripetal motion. When negotiating around a bend (which is just really traveling a fraction of a circular path, there’s some interesting physics at work.
At any given moment, the direction of the velocity will be straight ahead, but the force and acceleration will be pointing along the radius of the circle, towards the center. So, while turning, the body wants to move along the path of the velocity, and you’ll wind up leaning that way, making maintaining balance a little trickier.
Another interesting affect about turning while on a bicycle is called “counter-steering.” If you were to travel along a straight path and simply turn the wheel to the right, you’d simply fall over. This is because the center of mass must be under the bicycle in order to remain upright. Turning the wheel moves the center of mass out from under the bike. In order to successfully turn, you must first lean steer the bike slightly in the opposite direction of the turn in order to shift the center of mass to the correct position so you can later lean for the turn. It’s the same principle as balancing any object on your hand. You have to move the bottom of the object to the direction that the top of the object is falling, in order to reposition the center of mass. While this lean slight turn in the opposite direction is necessary for all speeds, it’s more noticable at high speeds, which is why decreasing velocity for a tighter turn in a good idea. But, if you decrease the speed too much, momentum will be lost (to friction) and the bike and rider will fall over. (thanks to Felstatsu for the correction)
I hope this answered The Scientific Indian’s question, and I hope all the physics is right. Please post any further questions or [hopefully no] errors.
Fixing the computer
June 6th, 2008 ecoliI’m bringing in my laptop to get fixed today, after I finish backing up my important files. I can’t wait around anymore waiting for my damaged hard drive to fix itself. I hope Best Buy’s warranty covers this one, because this is one thing I have no desire to pay for.
I’m not sure how long they’ll have it for, but going by my other experiences with Best Buy’s Geek squad, it will be on the order of weeks. I’m not sure what my computer/net access will be like during that time.
Internet Addiction Test
June 5th, 2008 ecoliAddiction to the internet is a serious problem and becoming worse the more life becomes ‘web-based.’ Apparantly, I’m no exception.
Calculate your own internet addiction score (assusingly) at this site. I scored a 62:
You are experiencing occasional or frequent problems because of the Internet. You should consider their full impact on your life.
I guess I’ll try to do that, right after I play some flash games, stumble upon sites for an hour and check SFN and scienceblogs.com.
As if we need a reason to drink
June 5th, 2008 ecoliBut having one doesn’t hurt.
A case for letting the free market do it’s thing
June 5th, 2008 ecoliThis graph from the NY times, kindly provided by Jake Young, at Pure Pedantry provides a good case for letting the market just do it’s thing, when it comes to alternative energies in regards to transportation.
If you’re an environmentalist, or if you don’t work for big oil, high gas prices is a good thing. When costs are artificially low, there’s little incentive for companies to produce alternative energies or hybrids. But, these charts show that inflated prices do, in fact, bring down the rate of fuel consumption (less driving). Now, corporations can only continue to inflate prices so much, before people start opting out of personal automobile use altogether, travel overseas by steamboat and start biking to work. In order for energy companies to keep selling energies, they’ll have to develop alternative sources.
Oil subsidies, paid for out of our taxes, keeps oil prices artifically low and less responsive to the laws of demand. This is harmful to our economy by preventing the development of alternative energies and harmful to our environment in the same respect.
If the gas tax is repealed for the summer, it will have a similiar effect by making gas prices appear cheaper, increasing demand and delying alternative technologies. The gas tax is needed to keep our public roadways in shape. Hillary’s proposal to add a windfall tax to oil companies and then fine companies millions who jack up prices to compensate for the loss is, at best, ridiculous. You can’t fine companies for trying to maintain their profits, and this would never be approved by a Bush appointed FTC administration anyway. Hillary’s plan would screw federal highways, because there’s no altervative source of income for this tax. And, it would delay the production of badly needed alternative energy by messing with the laws of demand. Leave the free market alone!
Social networking
June 4th, 2008 ecoli…. for farmers. I’d say this is a good way to promote self-initiated sustainability practices. O, internet, dost thou have a solution for everything?
via Science blog’s Worlds Fair
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