Airport security: two words which fray the nerves of even seasoned travelers. How did we end up with a system both disturbingly intrusive and dangerously ineffective? Privacy advocates have (rightly) complained that the current procedures in place in the United States are “security theater,” succeeding only in making the average flier uncomfortable. Surely we can do better.

Two new security systems seek to harness the sensing abilities of nature in an unnatural way–by teaching mice and plants to detect explosives. Future versions of these biological bomb detectors may eventually eliminate the dreaded security gate, helping make our business trips safer and stress-free.

The “mouse sensor,” developed by Israeli firm BioExplorers, promises a more sensitive, less labor-intensive replacement for the machines and dogs which currently detect contraband. And if rodents give you the creeps, don’t worry. You, and your bags, are safely sequestered from the living portion of the security system, as explained in New Scientist:

Along one side of an archway, a detection unit contains three concealed cartridges, each of which houses eight mice. During their 4-hour shifts in the detector, the mice mill about in a common area in each cartridge as air is passed over people paused in the archway and through the cartridge. When the mice sniff traces of any of eight key explosives in the air, they are conditioned to avoid the scent and flee to a side chamber, triggering an alarm. To avoid false positives, more than one mouse must enter the room at the same time.

A recent test of the mice in a Tel Aviv mall proved promising. The rodents sniffed out all of the mock explosives, with a false positive rate of just 0.1%, or 1 in 1000 people.

But while using mice instead of dogs makes sense from a cost and labor perspective, the BioExplorers model is not quite a quantum leap forward. After all, it still requires passengers to pass through a designated security area, a concentration of people which then becomes a target for attack. An ideal system would be ubiquitous and inconspicuous–constantly sampling the air for signs of concern, maintaining travelers’ privacy, and avoiding the crowds that terrorists covet.

Why not make the airport decor part of the security system? That’s the unorthodox approach taken by June Medford and her colleagues at Colorado State University, who have developed an intricate way for plants to sniff out TNT, using modified versions of genes found in bacteria.

Let’s take a step back. Though single-celled organisms, by definition, can’t have a nose, they still have simple means of detecting chemicals wafting around in their environments. Dedicated sensors on their cell membranes can find food (say, simple sugars), and the bacteria then orient themselves to suck up as much of it as possible. Other sensors can detect toxins, prompting the bugs to flee. This process is called chemotaxis.

Medford’s team took those bacterial sensing proteins and modified them so that they were sensitive to TNT. (Using the same method, it should be possible to create detectors for any chemical of interest.) But that wasn’t enough. After all, a detection system is worthless without an output–some way for the detector to say, “I’ve found TNT, panic!” And unlike a dog, or even a mouse, plants aren’t exactly communicative.

So the team created a genetic circuit which enables the plant to sound an alarm. When a plant senses TNT in the environment, it begins to bleach, by disrupting its own chlorophyll production. Thus far, the plants have “de-greened” at TNT levels as low as 23 parts per billion. In other words, on a future trip, watch out for pale, but otherwise healthy plants: they may be trying to tell you something’s amiss.

Both systems still have their issues. The BioExplorers team is trying to design a way to  automate the care and feeding of their mice, making it completely hands-free. And the plant system isn’t very quick: while the de-greening starts immediately, it can take as much as a day to be noticeable. Hopefully, both systems will continue to be refined, and their development will help inspire a larger discussion about the ways to make airport security less intrusive and more capable.

For more on the plant-based TNT detection system:

Antunes, M., Morey, K., Smith, J., Albrecht, K., Bowen, T., Zdunek, J., Troupe, J., Cuneo, M., Webb, C., Hellinga, H., & Medford, J. (2011). Programmable Ligand Detection System in Plants through a Synthetic Signal Transduction Pathway PLoS ONE, 6 (1) DOI: 10.1371/journal.pone.0016292

Photo credit: Flickr/redjar

A sample of last week’s important, intriguing, and curious science stories:

• “Snow tweets” project: measure the depth of snow where you are, then tweet #snowtweets <depth> at <location>. In Boston? It’s a lot. (Science for Citizens)
• Genomics-inspired poetry contest in Scotland announces its winners (Genomics Policy and Research Forum)
• Living art: a scientist/artist combination create petri dish paintings using E. coli (Public Radio International)
• An experiment hopes to create life using inorganic compounds–vastly different from the process thought to have happened on Earth (New Scientist, free subscription required)
• Birds may use quantum entanglement, aka “spooky action at a distance,” to see the Earth’s magnetic field (Wired Science)
• How can we better present science–and present better science–on TV? (John Hawks)
• A new technique promises cheaper, easier to make, more efficient solar cells (Technology Review)
• Inside the Kepler telescope’s quest to find Earth-like planets around distant stars (New York Times)

An energy-driven police state? Months-long traffic snarls? A gridless energy hackerspace? These caricatures of the world in 2040, developed recently by the Forum for the Future, envision a planet in thrall to humanity’s energy demands. But how dramatically will our cities truly transform in the next 30 years?

I’ve already developed my own vision of the future city in “Revisiting Tomorrowland.” Using the framework developed by Forum for the Future, we can see how this subtly more efficient metropolis will take shape.

FFF tracked the next 30 years of the city along two dimensions: the strength of government and the continued use of fossil fuels. Setting each at “high” or “low” produces four broad sketches of City 2040.

What they didn’t address was the likelihood of each scenario. But this is relatively straightforward once you look at the trends of the last decade.

Government: FFF’s “strong government” scenarios are comically dystopian, and the events of the last two months alone are enough to prove their implausibility. In a world where Wikileaks holds governments accountable to their citizens, and grassroots “Twitter revolutions” have demonstrated those citizens’ power to effect change, it’s difficult to see how things like this will be possible:

• To maximise efficiency the “Global Food Council” dictates which crops will be grown where in the world (Planned-opolis)
• Governments impose stricter rules, and use increasingly sophisticated technology for monitoring and enforcement. They often mandate where you live within the city, how you travel, and how much energy you will use (Renew-abad)

This doesn’t necessarily mean that we’ll all be energy hogs. In fact, I think a more energy-efficient lifestyle will become routine, spurred by a desire to save money, the proliferation of smartphone apps (and their 2040s successors) helping us track our waste, and social pressure to help fight climate change.

A similar process will (and has already, in some cities) make public transportation more convenient by giving riders the chance to track buses and trains to the second, and helping administrators anticipate and curb delays.

Fossil fuels: Barring any miracles, fossil fuels will still be with us in 2040. But alternatives will improve enough to present true competition.

Again, a combination of social and economic pressure is already beginning to establish these trends. But which technology will reign supreme? It’s difficult to predict, and that’s important.

The United States has been faulted for weak public investment in alternative energy, but to me this doesn’t seem so alarming. The world of 2040, and beyond, will likely need a slew of energy sources. Favoring one (like corn-based ethanol) only discourages others, hampering our chances of unseating the established oil and coal systems.

So, the final tally puts my weak-government, low-carbon prediction in line with FFF’s Communi-city–the “gridless hackerspace” caricature mentioned earlier. And while that vision is clearly extreme, the principle is sound.

We’re experiencing a strange confluence of trends in the early 21st century. People are simultaneously swelling real-world population centers and building engaging virtual communities. This will ultimately increase individual choice, foster informal collaboration, and yes, promote sound environmental stewardship.

A look at the “Communi-city” caricature:

Photo credit: Flickr/jplust

A very quick video and story that shows how remarkable our brains (or in this case, dogs’ brains) really are. The photogenic pup above is my family dog, Bailey. Despite his youthful good looks, he’ll be turning 12 in a couple months. Talking to my parents over the weekend, I found out that Bailey’s had a rather interesting week: he went from being perfectly healthy (well, as healthy as dogs of that age are), to being completely unable to walk! It looked something like this:

Obviously, for my parents, it was pretty shocking to see Bailey staggering around, and they thought something was seriously wrong with him. But it turns out that this condition–called peripheral vestibular syndrome–is relatively common in older dogs.

As you may have guessed from the name, it’s a problem in the inner ear, or in the nerves between the inner ear and the brain, that causes severe disorientation. In Bailey’s case, he would gamely try to walk in a straight line, but end up veering way to the right and crash into obstacles in the house. When trying to stand still, he would have to find something to lean on to keep from falling over.

Now here’s the fascinating part. The symptoms come on without warning, and (strangely) without any defined cause, but in a very short time, affected dogs are able to reorient themselves. Within a couple days, Bailey was able to steady himself by “aiming to the left” of where he wanted to go, and now he even refuses help when navigating the stairs in my parents’ house.

It’s pretty remarkable how quickly the brain can compensate for this condition. Hopefully, as we find new ways to probe the connections of our own minds, we’ll discover that even more severe brain injuries can eventually be cured.

The last two weeks (or so) in science…if you’re in the Northeast, stay warm today!

• A controversial study claims that people choose friends who are genetically similar to themselves (Proceedings of the National Academy of Sciences)
• So much for keeping them in little plastic cases: a facility which keeps the stem cells from extracted baby teeth (Miami Herald)
• NIH tries to get into the drug discovery business (New York Times)
• Play arcade games that control real single-celled organisms! (Scientific American)
• And another computer game: ready to fold some RNA? (New Scientist)
• DNA test confirms that Americans domesticated dogs 10,000 years ago? Maybe…maybe not. (Christian Science Monitor)
• “Science on Screen,” a Boston institution, is taking its show national (WBUR)

As I mentioned on Twitter last night, NASA’s solar sail satellite (say that one three times fast), NanoSail-D, was scheduled to spread its wings around 10pm Eastern yesterday. Apparently, it has done so–though confirmation of the deployment won’t take place until today.

Pete Spotts at the Christian Science Monitor has a rundown of the mission, which tests a technology that may be carrying us–well, some of us–around the solar system before too long.

Each photon of light that hits a surface, even those currently emanating from your computer screen right now, exerts a tiny amount of force when it’s reflected or absorbed. This force isn’t enough to push us around here on Earth, but in space, without anything to counteract it, photons should be able to speed up a solar sailboat to staggering speeds–maybe even fast enough to make interstellar travel a possibility.

Of course, there are significant drawbacks, some of which will be tested by NanoSail-D. For starters, the sail needs to be extremely broad and thin, to maximize the effect of the photons pushing on it. (How broad and thin? NanoSail-D, which is only a test craft, has a surface area of 100 square feet, but is as thin as tissue paper.) This makes deploying the sail a very sensitive process.

And while the constant acceleration provided by a solar sail may make a craft travel at close to the speed of light, this acceleration takes place very slowly. After all, it’s a giant sheet of tissue paper being pushed on by light.

Finally, once having built up all that speed, a solar sailboat needs a way to slow down when it reaches its destination.  While a fiery end is usually a sign of a failed mission, that won’t be the case for NanoSail-D. The craft is designed to gradually slow down as it orbits the Earth, then dramatically burn up in the atmosphere in the next 3-4 months, to demonstrate the maneuverability of solar sail technology.

For instant updates on NanoSail-D, the craft is tweeting to all of us on terra firma; you can say hello @nanosaild.

Photo credit: NASA/MSFC/D. Higginbotham

Some stories that made it big–or flew under the radar–over the last week:

• Most of New England’s wetlands were created…and then later destroyed…within the last 300 years (New Scientist)
• Clinical trials set to begin for stem cell-based blindness therapy (Technology Review)
• CSI meets real life: scientists say they can now determine hair and eye color from DNA (Discover)
• Paper claiming to validate ESP included in Journal of Personality and Social Psychology, much to psychologists’ dismay (New York Times)
• Floridians don’t usually bat an eye when they see an alligator. Unless it happens to be orange (MySuncoast.com)
• A computer program which tracks shifts in the flu virus (Biomed Middle East)
• A controversial piece on the “decline effect,” the notion that impressive scientific results are usually cut down to size by future studies (New Yorker)
• How do you make yourself smarter? (Newsweek)

Happy 2011, everyone! This looks to be an exciting year at Science Park–after all, it’ll be our first full year in operation–so stay tuned. Here are some stories you might have missed in the holiday hullabaloo:

• Inside the Personal Genome Machine: a $50,000 DNA sequencer. And if the story wasn’t enough to satisfy your curiosity, the author will be adding additional commentary this week. (Forbes)
• Some companies have found that cutting their carbon emissions makes good economic sense–even without government incentives. (Technology Review)
• How an 1807 meteorite ignited American scientific prowess (Westport News)
• In war-scarred Iraq, archaeologists battle to preserve the ruins of Babylon (New York Times)
• What microRNAs can tell us about stem cells and cancer (Science Daily)
• Want to know how social someone is? Take a peek inside her brain–the amygdala tells all (Wired Science)

A quick addition to yesterday’s post about the weekend blizzard:

An article in the New York Times from last night seems to bolster my point–the “surprising” aspect of the storm was simply that holiday inattention made it appear to come out of nowhere. New York City, despite official denials, seemed especially unprepared. Three choice quotes from the piece…

• City officials maintain that they were closely monitoring the updates. But the deputy mayor in charge of overseeing the snow response, Stephen Goldsmith, had left New York for the Washington area.
• The decision would have far-reaching consequences: because of a quirk in the transit agency’s system, the plan chosen on Friday stays in effect all weekend. And the agency would not officially make the switch to Plan 4 until 11 a.m. on Sunday, when snow was already building up on the streets
• [T]he problems late Sunday underscored how the city could not rely on outside contractors to help with snow removal and other jobs in such storms, particularly during a holiday weekend.

Finally, about an hour after my post went up, Chris Mooney from Discover wrote down some of his own “weather vs. climate” thoughts at DeSmog Blog. His claim is that severe winter conditions are a symptom of climate change, but that it’s exceedingly difficult to convince anyone of that. People hear “global warming” and think “less snow.”

As I mentioned yesterday, pointing to specific weather events and trying to make a case for climate change out of them is a losing strategy. Why? Because it encourages the opposite reaction, the one Mooney is trying to prevent–people seeing a snowstorm and saying, “well, this must mean those scientists are wrong!”

This story and my frustration with political tweets are both part of a culture clash between some scientists/science writers and the people they claim are ignorant of science or “anti-science.” There is a way to talk about politically charged issues without being political: be unflinchingly honest, be respectful of dissenting views, and anticipate (if possible, eliminate) points that will provoke off-topic arguments.

The blizzard is important from a psychological perspective–why people react to events in certain ways, and so on–but as a point for or against climate change, it’s not evidence of anything.

A Christmas weekend blizzard wreaked havoc on holiday travelers (including yours truly), and prompted a chorus of hostile reactions along the Eastern Seaboard. One notable comment: Pennsylvania governor Edward Rendell griped about the decision to postpone Sunday night’s Vikings-Eagles game, claiming it to be part of the “wussification of America.”

An article in the Christian Science Monitor sums up the complaints of Rendell and his ilk, and wonders why Americans were stunned by this particular storm. One proffered explanation for our “hyperbolic” response? We’re getting spoiled by the warm winters associated with climate change. I beg to differ.

Let’s start with the postponed football game. Remembering that nearly an entire weekend of English Premier League soccer (football for non-Americans) was wiped out earlier this month because of snow, I predicted early Sunday that the game in Philadelphia would be moved. In both cases, it wasn’t the field conditions that caused problems–snowy football games are not extraordinary–but the safety of traveling fans.

While making a hasty Sunday evening return to Boston, I noticed that the roads, even major highways, appeared to be untreated and unplowed. Something similar happened during a Sunday snowstorm when I was at Duke a few years back, and I think the explanation is rather simple: it’s difficult to get city employees to work on a Sunday, and in this case the day after Christmas. I also suspect that many people weren’t exactly glued to the news over the holiday weekend, and were caught off-guard by the storm’s ferocity.

But something else seemed off about the Monitor piece: it’s part of a disturbing trend to tie weather events to climate change. Two prominent examples:

The daughter and grandchildren of Oklahoma Republican James Inhofe, the Senate’s most outspoken climate-change skeptic, built an igloo a snowball’s throw from the Capitol, bearing signs saying “Al Gore’s New Home” and “Honk if you [heart] Global Warming.”

“I thought the use of imagery from Hurricane Katrina was inappropriate and unnecessary in this regard, as there are plenty of disturbing impacts associated with global warming for which there is much greater scientific consensus,” said Brian Soden, a University of Miami professor of meteorology and oceanography.

Taking a day’s worth of weather and shouting, “see, global warming?” or “what global warming?” is like flipping a coin twice, getting heads both times, and using that as evidence that the coin is unfair. While we’re doing our best to explain what we know about climate science, let’s take the opportunity to explain the scientific method as well. It takes more than one trial to make a conclusion.

So, rather than jumping to “wussified America,” or a nation coddled by climate change-induced warm winters, let’s be more rational about the Christmas blizzard of 2010. Travelers and city officials were surprised by a strong storm because the holiday weekend meant nobody was paying attention to the weather.

Image credit: Flickr/Andrew Teman