Author Archives: curiouscat

Amazonian Ant Species is All Female, Reproduces By Cloning

The ants reproduce via cloning – the queen ants copy themselves to produce genetically identical daughters. This species – the first ever to be shown to reproduce entirely without sex – cultivates a garden of fungus, which also reproduces asexually.
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Dr Himler’s interest in Mycocepurus smithii was originally sparked not by their unusually biased sex ratio, but by their ability to cultivate crops. “Ants discovered farming long before we did – they have been cultivating fungus gardens for an estimated 80 million years.

“They collect plant material, insect faeces and even dead insects from the forest floor and feed it to their crops,” she said.

New Yorkers Help Robot Find Its Way in the Big City

Tweenbots by Kacie Kinzer

I wondered: could a human-like object traverse sidewalks and streets along with us, and in so doing, create a narrative about our relationship to space and our willingness to interact with what we find in it? More importantly, how could our actions be seen within a larger context of human connection that emerges from the complexity of the city itself? To answer these questions, I built robots.
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Tweenbots are human-dependent robots that navigate the city with the help of pedestrians they encounter. Rolling at a constant speed, in a straight line, Tweenbots have a destination displayed on a flag, and rely on people they meet to read this flag and to aim them in the right direction to reach their goal.
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The results were unexpected. Over the course of the following months, throughout numerous missions, the Tweenbots were successful in rolling from their start point to their far-away destination assisted only by strangers. Every time the robot got caught under a park bench, ground futilely against a curb, or became trapped in a pothole, some passerby would always rescue it and send it toward its goal. Never once was a Tweenbot lost or damaged. Often, people would ignore the instructions to aim the Tweenbot in the “right” direction, if that direction meant sending the robot into a perilous situation. One man turned the robot back in the direction from which it had just come, saying out loud to the Tweenbot, “You can’t go that way, it’s toward the road.”

Very cool, fun and interesting. Cute integration of technology, psychology and an inquisitive scientific mind.

Home Engineering: Reading in Bed

Photo of Kindle, with read-in-bed holder by Randall Munroe

By Randall Munroe, author of the great XKCD comic, The Pursuit of Laziness

Since I was a kid, I’ve been looking for the perfect way to read in bed.
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I recently got a Kindle. I was intending to use it mainly as a mobile web browser, but I’ve surprised myself by using it to read an awful lot. And, with apologies to all the bibliophiles out there, I find the ergonomics better than a paperback. When snacking and reading, I can lay it flat on a table without the use of a book weight to hold it opened, and when lying in bed, I don’t have to keep moving it to read.

But it’s not perfect. There’s no way to hold it with a finger on the ‘next page’ buttons that doesn’t require a few muscles to hold it upright
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I got out of bed one night, went to the closet, and got a steel coat hanger and some pliers. After a few minutes of twisting, I created this

Continue reading →

Honda’s Robolegs Help People Walk

The devices combine sensor-driven motors and weight-bearing chassis to guide strides and support body weight. Though derived from technologies pioneered during the ASIMO’s quarter-century of development, their use could be deeply human, boosting manual laborers or assisting people unable to walk without help.
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The devices are still in the research stage, and Honda has not yet formalized plans to go commercial. If they do, the market could be large, and not only in Japan. The number of Americans aged 65 and older is expected to double by 2030. More than 17 million report difficulty climbing stairs or walking a quarter-mile.

Home Experiment: Deriving the Gravitational Constant

Deriving the Gravitational Constant by Joe Marshall

In the summer of 1985 I was at home convalescing and being bored. It occurred to me one day that if Cavendish could determine the gravitational constant back in 1798, I ought to be able to do something similar
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Cavendish cast a pair of 1.61 pound lead weights. I found a couple of 2-pound lead cylinders my dad had lying around. I used duct tape to attach them to a 3-foot wooden dowel. Cavendish used a wire to suspend the balance, I used nylon monofilament. To determine the torsion of the fiber, you wait until the balance stops moving (a day or two) and then you slightly perturb it. The balance will slowly oscillate back and forth. The restoring force is calculated from the period of oscillation. Cavendish had a 7-minute period. My balance had a 40 minute period (nylon is nowhere near as stiff as wire).

Cavendish used a pair of 350 pound lead balls to attract the ends of the balance from about 9 inches away. I put a couple of 8 pound jugs of water about an inch away. The next trick was to measure the rotation of the balance. Cavendish had a small telescope to read the Vernier scale on the balance. I used some modern technology. I borrowed a laser from Tom Knight (Thanks again!), and bounced it off a mirror that I mounted on the middle of the balance. This made a small red dot on the wall about 20 feet away. (I was hoping this would be enough to measure the displacement, but I was considering an interferometer if necessary.)

To my surprise, it all worked. After carefully putting the jugs of water in place, the dot on the wall started to visibly move. Within a few minutes, it had moved an inch or two. I carefully removed the jugs of water and sure enough, the dot on the wall drifted back to its starting position.

Very cool example of a home physics experiment.

Bacteria Communicate Using a Chemical Language

Each person has about 1 trillion human cells and about 10 trillion bacterial cells. In the webcast Bonnie Bassler, Department of Molecular Biology at Princeton University, discusses the chemical language that lets bacteria coordinate defense and mount attacks (quorum sensing). The find has stunning implications for medicine, industry — and our understanding of ourselves.

Bacteria do all sorts of amazing things for us: educating your immune system to keep bad microbes out, they digest our food, they make our vitamins…

Fellowship Winners Announced

Several science and engineering fellowships and scholarships have announced winners recently:

NSF Graduate Research Fellowships
Goldwater Scholarships
Marshall Scholarships
Department of Defense (NDSEG) Fellowships – no online list of winners yet

From the NSF GRFP site:

Due to the complexity of the current budget situation, the 2009 GRFP awards will be announced in installments based on fields of study and other factors. The first installment is now available on FastLane. Awardees, as well as Applicants not recommended for funding, have been notified by email. Recipients of Honorable Mention and any additional Fellowship award offers will be forthcoming. Applicant ratings sheets will be available after all award announcements have been made. We thank you for your patience.

Find out more about these and other science and engineering fellowships and scholarships. Also see: How to Win a Graduate Fellowship – NSF Graduate Research Fellows 2008

The Software Developer Labor Market

With the economy today you don’t hear much of a desperate need for programmers. But Dr. Norman Matloff, Department of Computer Science, University of California at Davis, testimony to Congress (Presented April 21, 1998; updated December 9, 2002) on Debunking the Myth of a Desperate Software Labor Shortage is full of lots of interesting information (for current and past job markets).

The industry says that it will need H-1B visas temporarily, until more programmers can be trained. Is this true?

No, it’s false and dishonest… The industry has been using this “temporary need” stall tactic for years, ever since the H-1B law was enacted in 1990. In the early- and mid-1990s, for example, the industry kept saying that H-1Bs wouldn’t be needed after the laid-off defense programmers and engineers were retrained, but never carried out its promise. It hired those laid off in low-level jobs such as technician (which is all the retraining programs prepared them for), and hired H-1Bs for the programming and engineering work.

Unlike Dr. Matloff, and many readers of this blog, I am actually not a big opponent of H-1B visas. I believe we benefit more by allowing tech savy workers to work in the USA than we lose. I understand people fear jobs are being taken away, but I don’t believe it. I believe one of the reasons we maintain such a strong programming position is due to encouraging people to come to the USA to program.

I also do believe, there are abuses, under the current law, of companies playing games to say no-one can be found in the USA with the proper skills. And I believe those apposed to H-1B visas make reasonable arguments and this testimony is a good presentation of those arguments.

This obsession with specific skills is unwarranted. What counts is general programming talent – hiring smart people – not experience with specific software technologies.

Very true.

What developers should do.

Suppose you are currently using programming language X, but you see that X is beginning to go out of fashion, and a new language (or OS or platform, etc.) Y is just beginning to come on the scene. The term “just beginning” is crucial here; it means that Y is so new that there almost no one has work experience in it yet. At that point you should ask your current employer to assign you to a project which uses Y, and let you learn Y on the job. If your employer is not willing to do this, or does not have a project using Y, then find another employer who uses both X and Y, and thus who will be willing to hire you on the basis of your experience with X alone, since very few people have experience with Y yet.

Good advice.

Build Your Own Tabletop Interactive Multi-touch Computer

This is a fantastic Do-It_Yourself (DIY) engineering story. Very interesting, definitely go read the whole article: Build Your Own Multitouch Surface Computer

First, some acknowledgments are in order. Virtually all the techniques used to create this table were discovered at the Natural User Interface Group website, which serves as a sort of repository for information in the multitouch hobbyist community.
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In order for our setup to work, we needed a camera that senses infrared light, but not visible light. It sounds expensive, but you’d be surprised. In this section, we’ll show you how we created an IR camera with excellent resolution and frame-rate for only $35—the price of one PlayStation 3 Eye camera. “But that’s not an IR camera,” you say? We’ll show you how to fix that.

As it turns out, most cameras are able to sense infrared light. If you want to see first-hand proof that this is the case, try this simple experiment: First, find a cheap digital camera. Most cell phone cameras are perfect for this. Next, point it at the front of your TV’s remote control. Then, while watching the camera’s display, press the buttons on the remote. You’ll see a bluish-white light that is invisible to the naked eye. That’s the infrared light used by the remote to control the TV.
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Like the computer, the projector we used for the build was something we scavenged up. The major concern for a projector to use in this kind of system is throw distance—the ratio between projection distance and image size. Short-throw projectors, which are sold by all the major projector brands, work the best for this kind of project, because they can be set up at the bottom of the cabinet and aimed directly at the surface. Unfortunately, they also tend to be more expensive.

Ever thrifty, we went with a projector we could use for free: an older home-theater projector borrowed from a friend. Because of the longer throw distance on this model, we had to mount the projector near the top of the cabinet, facing down, and use a mirror to reflect the image up onto the screen. For this we ordered a front-side mirror (a mirror with the reflective surface on the front of the glass, rather than behind it) to eliminate any potential “ghosting” problems, caused by dual reflections from the front and back of the glass in an ordinary mirror.

What is on the Other Side of Earth?

Do you ever wonder what is on the exact opposite side of Earth? This website uses Google Maps to let you see: Antipodes Map. It also makes clear how much of the earth is covered in oceans. The entire continental USA is opposite ocean. Hawaii is opposite Botswana and Namibia. Hong Kong is opposite Argentina. Singapore opposite Ecuador. India, Ireland, Turkey, France and Egypt are among the many countries that opposite oceans. Madrid is opposite New Zealand.