Category Archives: Science

Ants Counting Their Step

Most ants get around by leaving smell trails on the forest floor that show other ants how to get home or to food. They squeeze the glands that cover their bodies; those glands release a scent, and the scents in combination create trails the other ants can follow.

That works in the forest, but it doesn’t work in a desert. Deserts are sandy and when the wind blows, smells scatter.
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It’s already known that ants use celestial clues to establish the general direction home, but how do they know exactly the number of steps to take that will lead them right to the entrance of their nest?

Wolf and Whittlinger trained a bunch of ants to walk across a patch of desert to some food. When the ants began eating, the scientists trapped them and divided them into three groups. They left the first group alone. With the second group, they used superglue to attach pre-cut pig bristles to each of their six legs, essentially putting them on stilts.
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The regular ants walked right to the nest and went inside. The ants on stilts walked right past the nest, stopped and looked around for their home…

I posted about this back in 2006: Ants on Stilts for Science, but the webcast by NPR is worth a new post.

Disrupting Bacterial Communication to Thwart Them

Interrupting Bacterial Chatter to Thwart Infection

To measure their own numbers, bacteria produce, release, and detect chemical signals called autoinducers. As a population of bacteria grows, it releases more autoinducer into its environment. When individuals detect that a threshold level of autoinducer is present, they change their behavior – by releasing a toxin, for example.

Bassler and her colleagues disrupted these lines of communication by interfering with molecules called acyl-homoserine lactone (AHL) autoinducers, which drive quorum sensing among a kind of bacteria known as Gram-negative bacteria. Gram-negative bacteria include Pseudomonas, E. coli and Salmonella, and other disease-causing microbes. In the study, the team focused on Chromobacterium violaceum, which rarely infects human, but can be lethal to other organisms. C. violaceum lends itself to studies of quorum sensing because it produces a readily detected, bright purple dye when it detects that its population has reached a critical mass.
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The experiment shows that interfering with quorum sensing may provide an alternative to traditional antibiotics, Bassler says, and circumvent the problem of resistance that antibiotics foster by killing off susceptible bacteria but allowing resistant ones to survive and propagate.

President Obama Speaks on Getting Students Excited About Science and Engineering

The President announces the “Educate to Innovate” initiative, a campaign to get students excited about pursuing careers in science, technology, engineering and mathematics. Quotes from President Obama from his speech – (see webcast above):

“As President, I believe that robotics can inspire young people to pursue science and engineering.”

“Now the hard truth is that for decades we’ve been losing ground. One assessment shows American 15-year-olds now rank 21st in science and 25th in math when compared to their peers around the world.”

“And today, I’m announcing that we’re going to have an annual science fair at the White House with the winners of national competitions in science and technology. If you win the NCAA championship, you come to the White House. Well, if you’re a young person and you’ve produced the best experiment or design, the best hardware or software, you ought to be recognized for that achievement, too. Scientists and engineers ought to stand side by side with athletes and entertainers as role models, and here at the White House we’re going to lead by example. We’re going to show young people how cool science can be.”

“improving education in math and science is about producing engineers and researchers and scientists and innovators who are going to help transform our economy and our lives for the better.”

Re-engineering the Food System for Better Health

Good food nation

According to the Centers for Disease Control, between 1980 and 2006 the percentage of obese teenagers in the United States grew from 5 to 18, while the percentage of pre-teens suffering from obesity increased from 7 to 17.
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Obesity is widespread due to our national-scale system of food production and distribution, which surrounds children – especially lower-income children – with high-calorie products…
90 percent of American food is processed – according to the United States Department of Agriculture – meaning it has been mixed with ingredients, often acting as preservatives, that can make food fattening.
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Now, in another report finished this October after meetings with food-industry leaders, the MIT and Columbia researchers propose a solution: America should increase its regional food consumption.
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Only 1 to 2 percent of all food consumed in the United States today is locally produced. But the MIT and Columbia team, which includes urban planners and architects, believes widespread adoption of some modest projects could change that, by increasing regional food production and distribution.

To help production, the group advocates widespread adoption of small-scale innovations such as “lawn to farm” conversions in urban and suburban areas, and the “10 x 10 project,” an effort to develop vegetable plots in schools and community centers. Lawns require more equipment, labor and fuel than industrial farming nationwide, yet produce no goods. But many vegetables, including lettuce, cucumbers and peppers, can be grown efficiently in small plots.
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As Albright sees it, the effort to produce healthier foods “fits right in with the health-care reform effort right now because chronic diseases are so costly for the nation.” America currently spends $14 billion annually treating childhood obesity, and $147 billion treating all forms of obesity.

Good stuff. We need to improve health in the USA. The current system is unhealthy and needs to be improved. The public good from improving the health of society is huge (both in terms of individual happiness and economic benefits).

Florence Nightingale: The passionate statistician

She brought about fundamental change in the British military medical system, preventing any such future calamities. To do it, she pioneered a brand-new method for bringing about social change: applied statistics.
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he statistics changed Nightingale’s understanding of the problems in Turkey. Lack of sanitation, she realized, had been the principal reason for most of the deaths, not inadequate food and supplies as she had previously thought.
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As impressive as her statistics were, Nightingale worried that Queen Victoria’s eyes would glaze over as she scanned the tables. So Nightingale devised clever ways of presenting the information in charts. Statistics had been presented using graphics only a few times previously, and perhaps never to persuade people of the need for social change.

Applied statistics is a tool available to all to achieve great improvement. Unfortunately it is still very underused. As George Box says: applied statistics is not about proving a theorem, it’s about being curious about things. The goal of design of experiments is to learn and refine your experiment based on the knowledge you gain and experiment again. It is a process of discovery.

Web Gadget to View Cell Sizes to Scale

Image of cell size gadget from University of Utah

The Genetic Science Learning Center, University of Utah has a nice web gadget that lets you zoom in on various cells to see how large they are compared to each other. Above see a red blood cell, x chromosome, baker’s yeast and (small) e-coli bacterium.

A red blood cell is 8 micron (micro-meter 1/1,000,000 of a meter). E coli is 1.8 microns. Influenza virus is 130 nanometers (1/1,000,000,000 a billionth of a meter). Hemoglobin is 6.5 nanometers. A water molecule is 275 picometers (1 trillionth of a meter).

The Psychology of Choice: We can be Overwhelmed

Is less always more? by Dave Munger

shoppers with just a few flavors of jam to choose from are more likely to buy than those given dozens of options (including the original choices). It’s as if we’re paralyzed when we have a large number of options to choose from, and so we end up getting nothing.
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Significantly more students bought the pens when there was a middle number of choices than when there were either high or low numbers of choices. So we appear to prefer a moderate number of choices — not too many, and not too few.

Shah and Wolford believe that purchasing patterns are likely to be similar for a wide range of products — although depending on the particular product, the optimal number of choices might be higher or lower than the 8-12 range they found for roller-ball pens.

In The Paradox of Choice – Why More Is Less, Barry Schwartz discusses related ideas and mentions the only kind of mobile phone you can’t get not is a simple one.

Science Explained: RNA Interference

Explained: RNA interference

Every high school biology student learns the basics of how genes are expressed: DNA, the cell’s master information keeper, is copied into messenger RNA, which carries protein-building instructions to the ribosome, the part of the cell where proteins are assembled.

But it turns out the picture is far more complicated than that. In recent years, biologists have discovered a myriad of other molecules that fine-tune this process, including several types of RNA (ribonucleic acid). Through a naturally occurring phenomenon known as RNA interference, short strands of RNA can selectively intercept and destroy messenger RNA before it delivers its instructions.
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Double-stranded RNA molecules called siRNA (short interfering RNA) bind to complementary messenger RNA, then enlist the help of proteins, the RNA-induced silencing complex. Those proteins cleave the chemical bonds holding messenger RNA together and prevent it from delivering its protein-building instructions.

This article from MIT is one, of many, showing MIT’s commitment to science education of the public. Good job, MIT.

Open Science: Looking at Dust

Open access paper: Migration of Contaminated Soil and Airborne Particulates to Indoor Dust.

Indoor dust is a mixture of soil tracked into a residence, particulate matter derived from ambient outdoor air, and importantly, organic matter. Indoor dust is about 40% organic matter by weight in residential housing. Particles tracked into a residence are redistributed on floor surfaces account for over 60% of the dust mass on floors.

Energy Secretary Steve Chu Speaks On Funding Science Research

Energy Secretary Steve Chu (and Nobel Laureate) speaks with Google CEO Eric Schmidt about science research. One of the things Steve Chu is doing is funding high risk experiments that have great potential. This is something that is often said should be done but then people resort to safe investments in research. Taking these risks is a very good idea.

This is another example the remarkable way Google operates. The CEO actually understands science and the public good. Google also provides a huge amount of great material online in the form of webcasts of those speaking at Google. Google behaves like a company run by engineers. Other companies have engineers in positions of power but behave like companies run by any MBAs (whether they are lawyers, accountants, marketers or engineers).