Stories tagged Math

Jun
12
2008

More than anything: he just wants you to have good, clean fun.
More than anything: he just wants you to have good, clean fun.Courtesy publicinsomniac
A Dutch study has shown that, if anything, Friday the 13th is actually a little safer than other days of the year.

So you've got nothing to worry about tomorrow. Except flesh eating bacteria, psychopathic killers, and sour milk. You never know.

Jun
01
2008

Another dismal post about the dismal science.

Today, we look at The Copenhagen Consensus. A group of economists are presented with a thought experiment: let’s say you had $75 billion to spend on solving one of the world’s problems – how would you allocate your funds?

Economists, being the dismal people that they are, take no account of what is “moral” or “right” or what “ought” to be done. They just try to figure out where you get the biggest bang for your buck. Their answer? Micronutirents for kids. Providing vitamin A and zinc to 80 percent of the 140 million children who lack them would provide almost $17 in health benefits for every dollar invested.

Other items in the top ten:

  1. Micronutirents for kids
  2. Expanding free trade
  3. Fortifying foods with iron and salt
  4. Expanding immunization coverage of children
  5. Biofortification
  6. Deworming
  7. Lowering the price of schooling
  8. Increasing girls' schooling
  9. Community-based nutrition promotion
  10. Support for women's reproductive roles

The majority of the most-efficient solutions deal with health, thus proving the old saying, an ounce of prevention is worth a pound of cure.
The least-efficient proposal was a plan to mitigate global warming. Nobel Prize-winning economist Thomas Schelling noted that that spending $75 billion on cutting greenhouses gases would achieve almost nothing. In fact, the climate change analysis presented to the panel found that spending $800 billion until 2100 would yield just $685 billion in climate change benefits.

Economist Richard Nordhaus, in his book A Question of Balance: Weighing the Options on Global Warming Policies, draws a similar conclusion. Projects to massively reduce greenhouse gases end up costing more than they deliver—in some cases, many trillions of dollars more. OTOH, investing in alternative energy (wind, solar, etc.) and bio-engineering can produce great results for the amount spent on them.

The economists at Copenhagen felt funding research and development of low-carbon energy technologies was worthwhile, and ranked it 14th out of the 30 proposals they considered.

Other items at the bottom of the priorities list are proposals to reduce air pollution by cutting emissions from diesel vehicles; a tobacco tax; improved stoves to reduce indoor air pollution; and extending microfinance. These are not necessarily bad ideas. It’s just that other proposals provide more bang for the 75 billion bucks.

May
28
2008

Babs may have been on to something: It's not that girls can't do math--they just don't want to.
Babs may have been on to something: It's not that girls can't do math--they just don't want to.Courtesy CherrySoda!

Remember a few years ago, when Mattell got in trouble because a talking Barbie said Math is hard? Reinforced negative sterotypes. And then, a few years later, Harvard president Larry Summers noticed that there were more men than women in advanced mathematics, and speculated on a number of reasons, including culture and genetics. He got in trouble, too.

Well, a new study shows that a large part of a reason there are so few women pursuing careers in mathematics is because … they don’t want to. Given the choice, most girls choose not to pursue math. Not because it’s hard. Not because they can’t do the work. Just because they don’t want to.

This, in an odd way, feeds into our earlier conversation about the relative happiness of liberals vs. conservatives. Most conservatives value free markets, where millions of individuals make their own choices. Conservatives of a libertarian stripe place great emphasis on individual autonomy and responsibility. Liberals (not all, but many) have a tendency to see societal forces having a greater impact on human behavior, oftentimes determining it. Thus the impulse to place society under central control.

Here’s an example of a case where the “social forces” explanation for why girls don’t pursue math (“they are discriminated against!” “society teaches them not to!”) is outweighed by the “individual autonomy” explanation (“I don’t wanna—I think it’s boring”).

Apr
12
2008

Grounded!: American Airlines recently grounded over 300 planes for maintenance.  Did their actions actually put travellers at greater risk?
Grounded!: American Airlines recently grounded over 300 planes for maintenance. Did their actions actually put travellers at greater risk?Courtesy Eugenio Palisi

Over the past several days, American Airlines grounded its fleet of MD-80 aircraft, yanking 300 planes out of service, cancelling over 3,000 flights, and stranding tens of thousands of passengers. The purpose was to fix faulty wiring to reduce the risk of fire.

While we can all agree that safety is a good thing, especially in air travel, Iann Murray wonders if the trade-off was worth it. Writing in The National Review, he notes that many of the stranded passengers no doubt ended up driving to their destinations. And, since air travel is significantly safer than automobile travel, those passengers were at a much greater risk of death or injury than had they flown the planes -- even with the substandard wiring.

This was a case where there were no good choices -- reducing risk in one area (airplanes) meant increasing risk in another area (automobiles). However, given the very low risk of failure, the airline could have fixed a few planes each day, and not massively interrupted service. But then, they would have been taking a risk -- if there had been just one accident with the faulty planes, the airline would have been to blame. Accidents on the highway, however, are not their fault, even if their actions had put more drivers in peril.

There's a reason they call Economics the dismal science.

Apr
11
2008

There's a great article ("Penny dreadful: they're horrid and useless. Why do pennies persist?") in the 3/31/08 issue of The New Yorker.

Pennies: Billions of coins, most of them pennies, are unaccounted for. Maybe D.B. Cooper has them all...
Pennies: Billions of coins, most of them pennies, are unaccounted for. Maybe D.B. Cooper has them all...Courtesy smackfu

I read it, and immediately thought of the Science Buzz penny poll. So, readers, here are a few more fascinating facts to add to the pile:

  • A penny minted before 1982 is 95% copper. At recent prices, that's $0.025' worth.
  • Newer pennies are 97.5% zinc, but since zinc has soared in value, too, producing a penny costs about $0.017.
  • If it takes any longer than 6.15 seconds, breaking stride to pick up a penny off the ground pays less than the federal minimum wage.
  • The US Mint took more than two years to manufacture its first million coins; the Philadelphia Mint makes that many every 45 minutes or so.
  • A typical Mint bag full of pennies contains only about four thousand dollars' worth, yet you'd need a forklift to move it to the back of your getaway vehicle.
  • "The average life span of American pocket change is thirty years. During the past thirty years, the US Mint has produced something like a half trillion coins, most of them cents, yet the Mint estimates that only about three hundred billion coins are currently in circulation. This estimate is probably high, since it includes coins that haven't budged from their coffee cans in years. Even so, the missing change is worth billions. Where is it? Except in rare cases, old coins, unlike old banknotes, aren't withdrawn from circulation by the Federal Reserve. People simply mislay them, eventually, in one way or another, and in most cases they disappear as permanently as if they had been dropped into the sea. Pocket change leaks from the economy the way air leaks from a balloon, and most of what leaks is pennies."

Lest you think I'm a strong advocate of eliminating pennies, let me add that a nickel now costs almost $0.10 to manufacture. But making a dollar coin costs only about $0.20.

In fact,

"In 2006, the Mint cleared $750 million on revenues of $2.3 billion, so it's in no immediate danger of violating its obligation not to spend more on manufacturing coins than it receives, from the Federal Reserve and other coin consumers, for manufacturing them."

You're wondering, "Who are those other coin consumers?" (I know I was...)

"Last year, the Mint sold some $872 million's worth of non-circulating coins and medals to collectors and to people who like to keep savings in precious metals."

Dying for more odd facts about currency? Read the article. (It goes on to suggest why we might consider giving up not only pennies and nickels, but also dimes and maybe even $1 bills.)

Apr
09
2008

Noted hurricane forecaster Dr. William Gray has offered up his 2008 Atlantic hurricane season predictions. (The season begins on June 1 and runs through November 30.)

Hurricane Katrina, 8/29/05: This image was taken by NOAA's Geostationary Operational Environmental Satellite (GOES).
Hurricane Katrina, 8/29/05: This image was taken by NOAA's Geostationary Operational Environmental Satellite (GOES).Courtesy NOAA

Gray's team, working out of Colorado State University, is predicting an above-normal season, with 15 named storms, 8 hurricanes, and 4 major hurricanes (category 3 storms or higher). Why? A La Nina pattern creates cool water conditions in the Pacific and warm sea surface temperatures in the eastern Atlantic. Warm sea surface temperatures are critical to the formation of hurricanes.

What's "above average"? An average hurricane season produces about 10 tropical storms and 6 hurricanes. In 2007, 14 tropical storms formed, and 6 of those strengthened into hurricanes. But 2005, of course, was a record-shattering year, with 28 storms, including Hurricanes Katrina and Rita.

Here's the Science Buzz feature on hurricanes.

Buzz thread on Hurricane Katrina, started on 8/29/2005.

Buzz thread on Hurricane Rita, started on 9/22/2005.

Buzz thread on the 2007 Atlantic hurricane season

Buzz thread on the 2006 Atlantic hurricane season

Do you know about the 1938 hurricane that crashed into New England?

Interesting weather websites

Share your natural disaster stories.

And, lastly, here are the hurricane names for 2008:

  • Arthur
  • Bertha
  • Cristobal
  • Dolly
  • Edouard
  • Fay
  • Gustav
  • Hanna
  • Ike
  • Josephine
  • Kyle
  • Laura
  • Marco
  • Nana
  • Omar
  • Paloma
  • Rene
  • Sally
  • Teddy
  • Vicky
  • and Wilfred
Apr
02
2008

Beauty is truth, truth beauty,—that is all      Ye know on earth, and all ye need to know.: Or, as the poets say, "hubba-hubba."
Beauty is truth, truth beauty,—that is all Ye know on earth, and all ye need to know.: Or, as the poets say, "hubba-hubba."Courtesy beardenb

An Israeli student has written a computer program to recognize beauty. Human volunteers were asked to rate the attractiveness of several dozen photo portraits. The photos, along with their scores, were fed into the computer. The computer measured the faces and looked for commonalities between the ones rated most attractive.

The human subjects then rated another set of photos. The computer reviewed these, and compared them to what it had learned with the first set. It then rated the new photos. The computer’s ratings were very close to those provided by the humans.

The most impressive thing about this experiment is that the computer learned by itself. The programmers did not give the computer a definition of beauty. Rather, they let the machine figure it out for itself. This is considered a major step forward for artificial intelligence.

And if you’re wondering, average faces with no distinguishing characteristics are considered the most beautiful, both by humans and computers.

Mar
14
2008

There are lots of songs about pi on You Tube. I liked this one best.

Mar
07
2008

Sometimes it’s best to just let the door close.: Keeping your options open entails some very real costs--sometimes more than the option is worth.
Sometimes it’s best to just let the door close.: Keeping your options open entails some very real costs--sometimes more than the option is worth.Courtesy George Karamanis

“Keep your options open.” Sounds like good advice, right? Turns out, it has hidden costs.

Professors Dan Ariely and Jiwoong Shin at MIT ran an experiment to test rational behavior. Test subjects played a computer game. On the screen were three doors. If they clicked on a door, it opened. Click on it a second time, and a number would appear, and they would earn that much money. Click on a different door and it opens, but the first door closes. Some doors had higher average payoffs than others. The object of the game is to get as much money as you can in 100 total clicks. (You can play the game—without the money, sorry—here.)

Obviously, the winning strategy is to find the door that pays the best, and then keep clicking on it. But then the evil professors threw a curve. They presented a second version of the game, where the doors shrank and eventually disappeared if you didn’t click on them. Subjects would waste clicks keeping the lower-paying doors from disappearing. On average, they earned 15% less for the privilege of keeping their options open.

Ariely and Shin hypothesize that players kept the less-valuable doors open, even though it cost them money, to avoid the pain of losing the door forever. We all hate to lose things. But sometimes the cost of keeping them around is more than they are worth. The game is a good lesson in the value of just letting things go.

Jan
09
2008

Tangled up in blue: A simple experiment shows why almost any long stringy thing will eventually tie itself into knots.
Tangled up in blue: A simple experiment shows why almost any long stringy thing will eventually tie itself into knots.Courtesy clickykbd

Telephone cords, power cords, proteins – anything long and thin, it seems, will eventually get tangled up in a knot. Two biophysicists think they know why.

Dorian Raymer and Douglas Smith of the University of California at San Diego built a knot-making machine – a simple container about the size of a box of tissues. They put string in the box, tumbled it ten times, and then checked to see if a knot had formed. They found that this very simple procedure produced spontaneous knotting about half the time.

Raymer and Smith say it all has to do with the way the free ends rotate relative to the rest of the string. This may help scientists understand biological molecules, like DNA, which are prone to tangling themselves up.

I will resist the urge to congratulate the scientists for solving this knotty problem.