Category Archives: Education

Energy-Efficient Microchip

Team develops energy-efficient microchip

The key to the improvement in energy efficiency was to find ways of making the circuits on the chip work at a voltage level much lower than usual, Chandrakasan explains. While most current chips operate at around one volt, the new design works at just 0.3 volts.

Reducing the operating voltage, however, is not as simple as it might sound, because existing microchips have been optimized for many years to operate at the higher standard-voltage level. “Memory and logic circuits have to be redesigned to operate at very low power supply voltages,” Chandrakasan says.

One key to the new design, he says, was to build a high-efficiency DC-to-DC converter–which reduces the voltage to the lower level–right on the same chip, reducing the number of separate components. The redesigned memory and logic, along with the DC-to-DC converter, are all integrated to realize a complete system-on-a-chip solution.

One of the biggest problems the team had to overcome was the variability that occurs in typical chip manufacturing. At lower voltage levels, variations and imperfections in the silicon chip become more problematic. “Designing the chip to minimize its vulnerability to such variations is a big part of our strategy,” Chandrakasan says. “So far the new chip is a proof of concept. Commercial applications could become available “in five years, maybe even sooner, in a number of exciting areas”

The World’s Hottest Chili

The World’s Hottest Chili:

The standard measure for such things is the Scoville Heat Unit, or SHU, named after Wilbur Lincoln Scoville, a chemist who in 1912 developed a method of assessing the heat given off by capsaicin, the active ingredient in chili peppers. JalapeÃ±o peppers measure about 5,000 SHUs. The bhut jolokia tops a million.
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Food scientists speculate that hot chilies have an unexpected side effect that boosts their popularity. A publication of the Brooklyn Botanical Garden in New York described it this way: “When capsaicin comes into contact with the nerve endings in the tongue and mouth, pain messengers, called neurotransmitters, are sent to the brain in a panic. The brain, mistakenly perceiving that the body is in big trouble, responds by turning on the waterworks to douse the flames. The mouth salivates, the nose runs and the upper body breaks into a sweat. The heart beats faster and the natural painkiller endorphin is secreted. In other words, you get a buzz.”

Water: Supercool and Strange

Supercool, and Strange

As liquids go, water is a radical nonconformist—differing from other liquids in dozens of ways (see the latest count at www.lsbu.ac.uk/water/anmlies). Most famous among water’s peculiarities is its density at low temperatures. While other liquids contract and get denser as they cool toward their freezing points, water stops contracting and starts to expand. That’s why ice floats and frozen pipes burst.
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Water gets even weirder at colder temperatures, where it can exist as a liquid in a supercooled state well below its ordinary freezing point. Recent evidence suggests that supercooled water splits its personality into two distinct phases—another oddity unseen in other liquids. And last year, water surprised scientists yet again, when they found that at –63 degrees Celsius, supercooled water’s weird behavior returns to “normal.”

The Decoy Effect

The Decoy Effect, or How to Win an Election

The human brain, however, always seeks simple answers. Enter the third candidate. Huber told some people there was also a choice of a four-star restaurant that was farther away than the five-star option. People now gravitated toward the five-star choice, since it was better and closer than the third candidate. (The three-star restaurant was closer, but not as good as the new candidate.)

Another group was given a different third candidate, a two-star restaurant halfway between the first two. Many people now chose the three-star restaurant, because it beat the new option on convenience and quality. (The five-star restaurant outdid this third candidate on only one measure, quality.)

What the decoy effect basically shows is that when people cannot decide between two front-runners, they use the third candidate as a sort of measuring stick. If one front-runner looks much better than the third candidate, people gravitate toward that front-runner. Third candidates, in other words, can make a complicated decision feel simple.

Treated Mosquito Nets Prevent Malaria

WHO Backs Free, Treated Mosquito Nets to Prevent Malaria

Long-lasting, insecticide-treated mosquito nets should be distributed free, rapidly and widely in malaria-endemic areas, World Health Organization officials said here Thursday, setting new guidelines for fighting the mosquito-borne disease around the globe.
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The WHO announcement was paired with what Kochi called “impressive” findings by Kenyan health authorities that widespread, free distribution of mosquito nets can effectively save children’s lives.

After several years of using a combination of free distribution and sales, the Kenyan government last year conducted a massive, almost military-style campaign to distribute without charge 3.4 million insecticide-treated mosquito nets over three days in 46 malaria-endemic districts across the country.

Among a monitored group of 3,500 children in four of those districts, the number sleeping under the nets increased nearly tenfold from 2004 to 2006, WHO said, citing Kenyan government figures. The result was 44 percent fewer deaths than among children not sleeping under nets. Insecticide-treated mosquito nets kill mosquitoes on contact. If enough nets are distributed and used, they can have a kind of collective impact of eradicating mosquitoes in a given area.

PLoS Medicine open access article: Increasing Coverage and Decreasing Inequity in Insecticide-Treated Bed Net Use among Rural Kenyan Children

Genetic Research Suggests Cats ‘Domesticated Themselves’

Why Do Cats Hang Around Us? (Hint: They Can’t Open Cans), Washington Post

The findings, drawn from an analysis of nearly 1,000 cats around the world, suggest that the ancestors of today’s tabbies, Persians and Siamese wandered into Near Eastern settlements at the dawn of agriculture. They were looking for food, not friendship.

They found what they were seeking in the form of rodents feeding on stored grain. They stayed for 12 millennia, although not without wandering off now and again to consort with their wild cousins. The story is quite different from that of other domesticated animals: cattle, sheep, goats, horses

Rainforests

John Hunter in Costa Rica

Facts about Rainforests by The Nature Conservancy

Covering less than 2 percent of the Earth’s total surface area, the world’s rainforests are home to 50 percent of the Earth’s plants and animals.
Seventy percent of the plants identified by the U.S. National Cancer Institute as useful in the treatment of cancer are found only in rainforests.
Less than one percent of the tropical rainforest species have been analyzed for their medicinal value.
Originally, 6 million square miles of tropical rainforest existed worldwide. But as a result of deforestation, only 2.6 million square miles remain.
At the current rate of tropical forest loss, 5-10 percent of tropical rainforest species will be lost per decade.
Every second, a slice of rainforest the size of a football field is mowed down. That’s 86,400 football fields of rainforest per day, or over 31 million football fields of rainforest each year.

Photo of John Hunter in Costa Rican rain forest, by Justin Hunter.

Teach Yourself Programming in Ten Years

Teach Yourself Programming in Ten Years by Peter Norvig

Get interested in programming, and do some because it is fun. Make sure that it keeps being enough fun so that you will be willing to put in ten years.
Talk to other programmers; read other programs. This is more important than any book or training course.
Program. The best kind of learning is learning by doing. To put it more technically, “the maximal level of performance for individuals in a given domain is not attained automatically as a function of extended experience, but the level of performance can be increased even by highly experienced individuals as a result of deliberate efforts to improve.” (p. 366)

Great Self Portrait

photo of astronaut's faceplate reflecting earth

Photo by, and of, Astronaut Clay Anderson, Expedition 15 flight engineer. He used a digital camera to expose a photo of his helmet visor during the mission’s third planned session of extravehicular activity (EVA) on the International Space Station (15 August 2007). Also visible in the reflections in the visor are various components of the station and a blue and white portion of Earth. During the 5-hour, 28-minute spacewalk, Anderson and astronaut Rick Mastracchio (out of frame), STS-118 mission specialist, relocated the S-Band Antenna Sub-Assembly from Port 6 (P6) to Port 1 (P1) truss, installed a new transponder on P1 and retrieved the P6 transponder.

NASA provides their content, photos etc. online in an open access spirit. When linking to content (especially images) it is best to provide context (and with the internet the easiest way to do is so is relevant links). You can find many low resolution pictures of the image above around the internet. Trying to find the context around the image is not so easy – it took me quite awhile to do so. I try to provide the context and links. Lately some more sites will link to some original sources but this is still done far to infrequently.

There are also still far too many pointy haired bosses (PHB) making decisions to break the web by killing pages: web pages must live forever. Those PHB’s decisions do reduce the great benefit of linking but it is still worth doing for those cases where web sites are managed by people with the knowledge and ability to manage an internet resource properly.

Photo: NASA – high resolution version

Swimmers’ Sunscreen Killing Off Coral

Swimmers’ Sunscreen Killing Off Coral Ker Than for National Geographic News:

Four commonly found sunscreen ingredients can awaken dormant viruses in the symbiotic algae called zooxanthellae that live inside reef-building coral species. The chemicals cause the viruses to replicate until their algae hosts explode, spilling viruses into the surrounding seawater, where they can infect neighboring coral communities.

Zooxanthellae provide coral with food energy through photosynthesis and contribute to the organisms’ vibrant color. Without them, the coral “bleaches”—turns white—and dies. “The algae that live in the coral tissue and feed these animals explode or are just released by the tissue, thus leaving naked the skeleton of the coral,” said study leader Roberto Danovaro of the Polytechnic University of Marche in Italy.

The researchers estimate that 4,000 to 6,000 metric tons of sunscreen wash off swimmers annually in oceans worldwide, and that up to 10 percent of coral reefs are threatened by sunscreen-induced bleaching.