Category Archives: Education

Sexy Math

British researchers, stated that men had 12.7 heterosexual partners in their lifetimes and women had 6.5.” These numbers, though Kolata doesn’t say so, are means, not medians. In this case, it’s indeed mathematically impossible that the numbers are correct. The medians in the British sample? Seven and four, same as in the American study—so you can stop worrying about a transatlantic promiscuity gap.

“It is logically impossible for heterosexual men to have more partners on average than heterosexual women,” she explains. “Those survey results cannot be correct.” Kolata even quotes a theorem to this effect, backed up by mathematician David Gale of Berkeley: The average number of partners has to be the same for men and women.

This article makes several good mathematical and scientific points, including the dangers of trusting reports by participants. Also I can see if this page is more popular than some of the other math posts. For awhile now I have noticed “sex 100” showing up as one of the terms guiding the most visitors to this site. I wondered what that could be – I just took a look: Bdelloid Rotifers Abandoned Sex 100 Million Years Ago. I think maybe those searchers didn’t exactly find what they wanted.

Mining the Moon

Mining the Moon by Mark Williams:

At the 21st century’s start, few would have predicted that by 2007, a second race for the moon would be under way. Yet the signs are that this is now the case. Furthermore, in today’s moon race, unlike the one that took place between the United States and the U.S.S.R. in the 1960s, a full roster of 21st-century global powers, including China and India, are competing.

Even more surprising is that one reason for much of the interest appears to be plans to mine helium-3–purportedly an ideal fuel for fusion reactors but almost unavailable on Earth–from the moon’s surface
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But a serious critic has charged that in reality, He3-based fusion isn’t even a feasible option. In the August issue of Physics World, theoretical physicist Frank Close, at Oxford in the UK, has published an article called “Fears Over Factoids” in which, among other things, he summarizes some claims of the “helium aficionados,” then dismisses those claims as essentially fantasy.

As I stated in January in Helium-3 Fusion Reactor: “This sounds pretty incredible to me and I find the claims of using fuel from the Moon economically to power our needs on Earth. Still it is interesting and just because it sounds fantastic does not mean it can’t be true. But I am skeptical.”

Revolving Doors

Every day I go into work I see about 15 people by bypass a revolving door (those using the revolving door average about 1.5 – including me) and use a standard door (and in fact 90% of those use an automatic handicap door open button – which leaves the door open for a good 5-10 seconds). MIT students have a page about the waste caused by people too lazy to use a revolving door:

On average 8x as much air is exchanged when a swing door is opened as opposed to a revolving door. That’s 8x as much new air that needs to be heated or cooled and that’s why using the revolving door is a great way to reduce energy requirements on campus.
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You’ve probably seen the signs around campus saying “Help MIT save energy. Please use the revolving door.” But does it really make any difference? Absolutely. Our estimates show that if everyone used the revolving doors at E25 alone, MIT would save almost $7500 in natural gas amounting to nearly 15 tons of CO2. And that’s just from two of the 29 revolving doors on campus!

As noted previously, for energy savings (greenhouse gas reduction…), not-so-glamorous conservation works best.

Textbook Revolution

Textbook Revolution is a resource on free textbooks and free related course materials. In general, I must say the prices of textbooks seem crazy. This is another tool great open access resource.

At Textbook Revolution, you’ll find links to textbooks and select educational resources of all kinds. Some of the books are PDF files, others are viewable only online as e-books. Most books are aimed at undergraduates, but there are at least a few resources at every level, from kindergarten to post-doc. All of the books are offered for free by their respective copyright holders for online viewing. Beyond that, each book is as individual as the author behind it.

Some examples: The Scientist and Engineer’s Guide to Digital Signal Processing by Steven W. Smith; Light and Matter by Benjamin Crowell; A First Course in Linear Algebra by Robert A Beeze; Programming Ruby: The Pragmatic Programmer’s Guide by
Dave Thomas and Introduction to Statistical Thought by Michael Lavine.

While on the subject of textbooks, I will plug my father’s book: Statistics for Experimenters – it is my blog so I get to do what I want 🙂

Brain Drain Benefits to the USA Less Than They Could Be

Study Points to ‘Brain-Drain’ of Skilled U.S. Immigrant Entrepreneurs to Home Countries. I am not totally sure reverse brain drain is the proper term. It appears to me this is really saying the size of the brain drain, coming to the USA, is less than it could be (many brains that came are returning). Yes in some senses it is a brain drain from the USA but still…

In this study, “Intellectual Property, the Immigration Backlog, and a Reverse Brain-Drain,” researchers offer a more refined measure of this rise in contributions of foreign nationals to U.S. intellectual property and analyze the possible impact of the immigrant-visa backlog for skilled workers. The key finding from this research is that the number of skilled workers waiting for visas is significantly larger than the number that can be admitted to the United States. This imbalance creates the potential for a sizeable reverse brain-drain from the U.S. to the skilled workers’ home countries.

“These findings are important, highlighting the invaluable contribution of foreign nationals to our country’s technological and economic vitality,” said Duke Provost Peter Lange, the university’s top academic officer. “We know from our own experience here that students from China, India and other nations can play an outstanding role in advancing knowledge and creating new jobs, especially in cutting-edge fields.”

I don’t think this result is going to decrease. And I believe the actual loss of scientists, engineers and entrepreneurs born in the USA for significant portions of their careers to other countries will increase dramatically over the next 25 years. I agree that it is in the interests of the USA to try and retain the ‘Brain Drain’ advantages it has been receiving.

Regular Aerobic Exercise for a Faster Brain

Lobes of Steel

Scientists have suspected for decades that exercise, particularly regular aerobic exercise, can affect the brain. But they could only speculate as to how. Now an expanding body of research shows that exercise can improve the performance of the brain by boosting memory and cognitive processing speed. Exercise can, in fact, create a stronger, faster brain.
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But something else happened as a result of all those workouts: blood flowed at a much higher volume to a part of the brain responsible for neurogenesis. Functional M.R.I.’s showed that a portion of each person’s hippocampus received almost twice the blood volume as it did before. Scientists suspect that the blood pumping into that part of the brain was helping to produce fresh neurons.

The hippocampus plays a large role in how mammals create and process memories; it also plays a role in cognition. If your hippocampus is damaged, you most likely have trouble learning facts and forming new memories. Age plays a factor, too. As you get older, your brain gets smaller, and one of the areas most prone to this shrinkage is the hippocampus. (This can start depressingly early, in your 30’s.) Many neurologists believe that the loss of neurons in the hippocampus may be a primary cause of the cognitive decay associated with aging.

‘Looming Crisis’ from NIH Budget

‘Looming crisis’ from NIH budget by Ted Agres:

“Promising research is now being slowed or halted,” said Edward Miller, dean of Johns Hopkins Medicine. “We are seeing veteran scientists spending time not in labs but on the fundraising circuit. We are seeing young researchers quitting academic research in frustration, having concluded that their chances of having innovative research funded by NIH are slim to none,” Miller told a Capitol Hill news conference yesterday.

The scientists released a report prepared by 20 leading researchers from a consortium of nine academic institutions and universities, that outlines the benefits of increased NIH funding on biomedical innovations, and warns of the negative implications should the present budget be left unaddressed. The report cited threats from unexpected new diseases, such as SARS and pandemic influenza, as well as obesity, HIV, and bioterrorism.

While Congress and the White House doubled NIH’s budget from 1998 to 2003, funding has failed to keep pace with inflation. NIH’s budget has hovered at around $28 billion, but once inflation is factored in, its purchasing power has fallen 13% over the past four years. According to the report, an average of eight out of ten NIH grant applications currently go unfunded, while at the National Cancer Institute, only 11 percent of grants are funded. “This is a recipe for disaster,” Miller said. “The number of termination letters at Johns Hopkins is up three-fold.”

Peak Soil

An interesting article. Obvious the author has a biased viewpoint (that doesn’t mean the conclusions are wrong but it certainly can make one cautious – just as if a drug company shows results that their drug is effective or safe – you just have to pay a bit more attention…). I would be interested in others thoughts on this. My perception (though it is just an opinion based on limited facts) is that topsoil loss is a problem and that using corn for ethanol is more a federal government payoff to buy votes than a wise national policy. I am less inclined to accept some of the more extreme suggestions in the article. Peak Soil: Why cellulosic ethanol, biofuels are unsustainable and a threat to America

“The nation that destroys its soil destroys itself.” – President Franklin D. Roosevelt
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When you take out more nutrients and organic matter from the soil than you put back in, you are “mining” the topsoil. The organic matter is especially important, since that’s what prevents erosion, improves soil structure, health, water retention, and gives the next crop its nutrition. Modern agriculture only addresses the nutritional component by adding fossil-fuel based fertilizers, and because the soil is unhealthy from a lack of organic matter, copes with insects and disease with oil-based pesticides.

I believe it makes sense to research things like bio-fuels. However I am not convinced massive payments to the political well connected is a wise course of action.

More on Amazing Aerogel

We added a post on aerogel earlier this month. Here is another article on the incredible substance – Scientists hail ‘frozen smoke’ as material that will change world:

It is expected to rank alongside wonder products from previous generations such as Bakelite in the 1930s, carbon fibre in the 1980s and silicone in the 1990s. Mercouri Kanatzidis, a chemistry professor at Northwestern University in Evanston, Illinois, said: “It is an amazing material. It has the lowest density of any product known to man, yet at the same time it can do so much. I can see aerogel being used for everything from filtering polluted water to insulating against extreme temperatures and even for jewellery.”
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It also has green credentials. Aerogel is described by scientists as the “ultimate sponge”, with millions of tiny pores on its surface making it ideal for absorbing pollutants in water. Kanatzidis has created a new version of aerogel designed to mop up lead and mercury from water. Other versions are designed to absorb oil spills.

Microchip Cooling Innovation

New technology has dramatic chip-cooling potential for future computers

The Purdue University researchers, in work funded by Intel Corp., have shown that the technology increased the “heat-transfer coefficient,” which describes the cooling rate, by as much as 250 percent. “Other experimental cooling-enhancement approaches might give you a 40 percent or a 50 percent improvement,” said Suresh Garimella, a professor of mechanical engineering at Purdue. “A 250 percent improvement is quite unusual.”
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The experimental cooling device, which was fabricated on top of a mock computer chip, works by generating ions – or electrically charged atoms – using electrodes placed near one another. The device contained a positively charged wire, or anode, and negatively charged electrodes, called cathodes. The anode was positioned about 10 millimeters above the cathodes. When voltage was passed through the device, the negatively charged electrodes discharged electrons toward the positively charged anode. Along the way, the electrons collided with air molecules, producing positively charged ions, which were then attracted back toward the negatively charged electrodes, creating an “ionic wind.”

This breeze increased the airflow on the surface of the experimental chip. Conventional cooling technologies are limited by a principle called the “no-slip” effect – as air flows over an object, the air molecules nearest the surface remain stationary. The molecules farther away from the surface move progressively faster. This phenomenon hinders computer cooling because it restricts airflow where it is most needed, directly on the chip’s hot surface.

via: Purdue University’s Ionic Wind Engine