Tag Archives: science explained

Demystifying the Memristor

The memristor — short for memory resistor – could make it possible to develop far more energy-efficient computing systems with memories that retain information even after the power is off, so there’s no wait for the system to boot up after turning the computer on. It may even be possible to create systems with some of the pattern-matching abilities of the human brain.
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By providing a mathematical model for the physics of a memristor, the team makes possible for engineers to develop integrated circuit designs that take advantage of its ability to retain information.

“This opens up a whole new door in thinking about how chips could be designed and operated,” Williams says.

Engineers could, for example, develop a new kind of computer memory that would supplement and eventually replace today’s commonly used dynamic random access memory (D-RAM). Computers using conventional D-RAM lack the ability to retain information once they are turned off. When power is restored to a D-RAM-based computer, a slow, energy-consuming “boot-up” process is necessary to retrieve data stored on a magnetic disk required to run the system.

The Life of the Queen Bee

A common mistake amongst non apiarists is the assumed fact that the queen directly controls the hive. Effectively, however, her duty is as an egg making machine. She can lay bout two thousand eggs a day in the spring. This amounts to more than her own weight in eggs each day. Surrounded continuously by workers, she needs for nothing. They give her food and take her waste away. They will also collect a pheromone which they then distribute to stop workers from starting queen cells.
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This very close up [follow link] of a queen bee shows one of its greatest – and smallest – enemies. The bee mite is an external parasite that attacks honey bees. It attaches itself to the bee’s body and sucks out its hemolymph. This is the blood analogue that is used by bees as they have an open circulatory system. Unfortunately the mite is more than just a pain in the neck. It can spread a host of viruses, including “Deformed Wing Virus” and the arrival of mites in a colony can often spell its demise. Scientists believe that the mite may contribute to the Colony Collapse Disorder (otherwise known as CCD) that is spreading throughout the United States.

10 Most Beautiful Physics Experiments

Science’s 10 Most Beautiful Experiments by George Johnson

Galileo’s experiment on falling objects

In the late 1500’s, everyone knew that heavy objects fall faster than lighter ones. After all, Aristotle had said so. That an ancient Greek scholar still held such sway was a sign of how far science had declined during the dark ages.

Galileo Galilei, who held a chair in mathematics at the University of Pisa, was impudent enough to question the common knowledge. The story has become part of the folklore of science: he is reputed to have dropped two different weights from the town’s Leaning Tower showing that they landed at the same time. His challenges to Aristotle may have cost Galileo his job, but he had demonstrated the importance of taking nature, not human authority, as the final arbiter in matters of science.
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Young’s double-slit experiment applied to the interference of single electrons

Though it is not simply made of particles, neither can it be described purely as a wave. In the first five years of the 20th century, Max Planck and then Albert Einstein showed, respectively, that light is emitted and absorbed in packets — called photons. But other experiments continued to verify that light is also wavelike.

It took quantum theory, developed over the next few decades, to reconcile how both ideas could be true: photons and other subatomic particles — electrons, protons, and so forth — exhibit two complementary qualities; they are, as one physicist put it, ”wavicles.”

Eratosthenes’ measurement of the Earth’s circumference -the librarian at Alexandria in the third century B.C. estimated the circumference of the planet

Assuming the earth is spherical, its circumference spans 360 degrees. So if the two cities are seven degrees apart, that would constitute seven-360ths of the full circle — about one-fiftieth. Estimating from travel time that the towns were 5,000 ”stadia” apart, Eratosthenes concluded that the earth must be 50 times that size — 250,000 stadia in girth.

Related: Book, The Ten Most Beautiful Experiments by George Johnson (not the same experiments) – Home Experiments: Quantum Erasing – Particles and Waves – theory of knowledge – scientific experiments

Do Dolphins Sleep?

Do dolphins sleep?, MIT:

Dolphins do sleep, but not quite in the same way that people do. They sleep with one half of the brain at a time and with one eye closed. Dolphins rest this way on and off throughout the day, switching which side of the brain they shut down. During these periods, everything inside the dolphin slows down, and the mammal moves very little.

Algorithmic Self-Assembly

Paul Rothemund, scientist at Cal Tech, provides a interesting look at DNA folding and DNA based algorithmic self-assembly. In the talk he shows the promise ahead for using biological building blocks using DNA origami — to create tiny machines that assemble themselves from a set of instructions.

Algorithmic Self-Assembly of DNA Sierpinski Triangles, PLoS paper.

I posted a few months ago about how you can participate in the protein folding, with the Protein Folding Game.

8 Percent of the Human Genome is Old Virus Genes

In Our Genes, Old Fossils Take On New Roles

It turns out that about 8 percent of the human genome is made up of viruses that once attacked our ancestors. The viruses lost. What remains are the molecular equivalents of mounted trophies, insects preserved in genomic amber, DNA fossils.

The thousands of human endogenous retroviruses, or HERVs, sketch a history of rough times during the 550 million years of vertebrate evolution. The best-preserved one, HERV-K113, probably arrived less than 200,000 years ago, long after human beings and chimpanzees diverged from a common ancestor.

But these retroviruses are more than just curiosities. They are some of the most important enemies we ever had. They helped mold the immune system that is one of the evolutionary marvels of life on Earth.

I must say there is tons of amazing stuff I learn about but I still find retroviruses amazing.

Blinking Cats: Friday Cat Fun #4

Blinking Cats

What is your cat trying to tell you? A blinking cat is a happy cat. Blinking in cats is a signal that they recognize the presence of another cat in their vicinity but they are not going to fight it. A blink sends the message: “You are my friend. I am not angry. I am not threatened, or threatening.”

This kind of message is very important in the wild, where cats battle for territory. Run across a neighboring cat and you’d better make your intentions clear, or you may find yourself in a fight. The blink serves to say: all’s well here.
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So, why do cats blink at us, when we aren’t cats and don’t understand such feline messages? Well — do you ever speak to your cat?

Life in a bubble

Hundreds of insect species spend much of their time underwater, where food may be more plentiful. MIT mathematicians have now figured out exactly how those insects breathe underwater.

By virtue of their rough, water-repellent coat, when submerged these insects trap a thin layer of air on their bodies. These bubbles not only serve as a finite oxygen store, but also allow the insects to absorb oxygen from the surrounding water.

“Some insects have adapted to life underwater by using this bubble as an external lung,” said John Bush, associate professor of applied mathematics, a co-author of the recent study.

Thanks to those air bubbles, insects can stay below the surface indefinitely and dive as deep as about 30 meters, according to the study co-authored by Bush and Morris Flynn, former applied mathematics instructor. Some species, such as Neoplea striola, which are native to New England, hibernate underwater all winter long.

Science Sortof Explains: Hiccups

photo of Red Hot Pepper by John Hunter

I love spicy food (Indian food is my favorite food). In my garden, this year, I am growing some spicy peppers (which honestly I don’t really like on their own – I have discovered). Still I eat them some and I get the hiccups almost every time. So I finally used Google to find out why. That lead to – MayoClinic on Hiccups:

A hiccup is an unintentional contraction of your diaphragm – the muscle that separates your chest from your abdomen and plays an important role in breathing. This contraction makes your vocal cords close very briefly, which produces the sound of a hiccup.

Although there’s often no clear cause for a bout of hiccups, some factors that can trigger acute or transient hiccups include: Eating spicy food. Spicy food may cause irritation to the nerves that control normal contractions of your diaphragm.

I must say the internet is great. Still that is hardly a great explanation for me. I almost never get the hickups eating spicy meals but every time I eat a hot pepper on its own I seem to (which happens very quickly and then ends pretty quickly – under 5 seconds). I guess somehow the other food in my mouth disrupts the potential nerve irritation so that it doesn’t cause a hiccup? It doesn’t seem like the raw pepper is hotter (higher Scoville Heat Unit) than the food, so I don’t think it is just a matter of more “heat” causing the hiccups.

Photo by John Hunter, Creative Commons Attribution-Share Alike (see requirements for use).

Dolphin Kick Gives Swimmers Edge

photo of Michael Phelps diving

Dolphin Kick Gives Swimmers Edge

Rajat Mittal, a professor of mechanical and aerospace engineering at the George Washington University, was studying dolphins for the U.S. Navy five years ago. “We were asked to understand how fish swim so efficiently,” Mittal says, “and it seemed like a natural extension to apply this to human swimming.”
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They decided to “essentially compare these swimmers to the dolphin, assuming that the dolphin is the ultimate swimmer,” Mittal says. “And the thing that we found is that Michael [Phelps] is able to use his body in a way that is very, very different from the other athletes, and also seems to be much closer to dolphins than we have seen for any other swimmer.”

The dolphin kick first hit Olympic swimming big-time 20 years ago, after Harvard backstroker David Berkoff figured out something fundamental. “It seemed pretty obvious to me that kicking underwater seemed to be a lot faster than swimming on the surface,” Berkoff says.

That’s because there’s turbulence and air on the surface of the water, and they create resistance. The “Berkoff Blastoff,” as it was called, was used at the start and after turns, with long stretches of that underwater undulating kick.

Follow the link for a video of Michael Phelps demonstrating the technique and more interesting details. Photo by A. Dawson shows Michael Phelps diving into the water at the 2008 U.S. Olympic Swimming Trials.