buy viagra lowest price cheap generic viagra order cialis in us order cheap viagra online cheap cialis in canada buy discount cialis viagra price find cheap viagra online generic viagra low cost viagra buy sildenafil in canada erectile dysfunction buying generic viagra cheap cialis from canada cialis 10mg buy viagra online buy sildenafil cheap buy cheapest cialis cialis rx order viagra no prescription buying viagra buying cialis online buy viagra from india cialis cheapest price order cialis cheap online order no rx cialis cialis 10 mg overnight viagra tablet viagra buy generic cialis online cialis bangkok buy generic viagra viagra canada find viagra online buy and purchase sildenafil online cheap generic cialis viagra rx no prescription cialis find cialis 50 mg viagra viagra vs cialis buy sildenafil online order cialis without prescription cheap viagra online cialis information viagra cost 100 mg viagra purchase viagra viagra viagra from canada buy viagra internet drug viagra online purchase order cialis no rx discount cialis discount viagra discount viagra without prescription viagra without rx certified viagra find discount viagra cialis no online prescription cost of viagra find cialis without prescription buy discount viagra online buy cheap cialis lowest price cialis viagra pharmacy online viagra cheap sale viagra order viagra online cheap cialis tablet order cialis overnight delivery buy cialis low price cheap viagra without prescription cheapest cialis price viagra online without prescription buy sildenafil low cost compare viagra prices online buy cialis on line buy cialis generic impotence viagra tablets buy viagra generic cialis buy viagra low price viagra purchase best price for viagra 25mg viagra buy cialis from india cialis drug order viagra on internet low cost cialis buy discount viagra impotence treatment viagra pill order viagra from us buy sildenafil in uk overnight cialis cialis soft tab viagra medication cialis cheap impotence pills discount cialis online cheapest cialis online order cialis from canada cialis no prescription viagra cheap drug cheap viagra tablets buy viagra without prescription viagra online pharmacy viagra approved find cheap cialis cost cialis buy viagra on line cialis 20 mg buy cialis cheap cheapest viagra free cialis buy cheap cialis online pharmacy cialis cialis without rx cialis overnight shipping compare cialis prices online cheap cialis overnight delivery cialis tablets 20 mg cialis order viagra from canada cheap viagra from usa buy cheap viagra internet cheapest cialis 10 mg cialis purchase cialis buy sildenafil citrate cheap cialis no prescription order generic viagra cialis online cheap cheap cialis on internet drug cialis buy sildenafil internet cialis from india no rx cialis viagra cheapest price where to buy cialis order cialis in canada cialis medication cialis pharmacy discount cialis no rx cialis no rx required viagra overnight shipping cialis sales buy cialis from canada cialis prescription cheap viagra in uk purchase cialis overnight delivery cialis price where to buy viagra viagra no rx required cheap viagra overnight delivery viagra india buying generic cialis cialis malaysia cialis pill cialis for order cialis soft order viagra in canada generic viagra online cialis for sale impotence medication online viagra viagra soft viagra pharmacy purchase viagra overnight delivery buy cialis on internet cialis canada order discount cialis online buy viagra overnight delivery cheapest viagra price buy cialis from us cheap cialis from usa generic cialis cheap viagra no rx lowest price for cialis buy sildenafil online without a prescription viagra vendors cost of cialis generic viagra cheap cialis free delivery viagra in malaysia viagra uk find cialis online order viagra without prescription find discount viagra online cheap cialis from uk drug viagra cialis in uk cialis without a prescription viagra in australia find no rx cialis drug cialis online purchase cialis free sample buy cialis internet viagra generic find cheap viagra cheapest generic cialis online find cheap cialis online compare cialis prices order viagra no prescription required viagra us cheap viagra in usa find discount cialis purchase cialis no rx no prescription viagra cialis online viagra no online prescription fda approved cialis cheap cialis pharmacy buy viagra no prescription required cialis side effects viagra in uk viagra no prescription viagra in us cialis pharmacy online find viagra cheapest generic cialis cost viagra buy viagra cheap buy cialis in canada buy cialis no prescription required buy cialis us order cialis from us 100mg viagra free viagra find discount cialis online cheap viagra cialis buy online cialis overnight buy sildenafil canada cialis 20mg cheapest cialis prices viagra without prescription order cheap viagra cheap price viagra buy no rx viagra purchase viagra no rx pharmacy viagra find viagra no prescription required cheapest generic viagra cialis in malaysia cialis purchase buy cialis lowest price order no rx viagra cheapest generic viagra online order viagra cheap cialis where to order viagra fda approved viagra buy no rx cialis purchase viagra without prescription cheap cialis no rx cialis online stores cheap cialis in uk find cialis on internet certified cialis price of viagra purchase cialis online cheapest viagra prices find viagra on internet buy cheapest cialis online buy discount cialis online buy viagra from us buy cheapest cialis on line cialis cheap drug buy cialis online cheap find cialis no prescription required cialis us cheap viagra pill viagra free sample cheap viagra tablet viagra online cheap cheap cialis in usa cheap cialis without prescription order viagra no rx order viagra cheap online viagra prescription discount cialis overnight delivery cialis australia buy viagra on internet cialis buy drug order viagra in us cialis vendors cialis tablet viagra drug viagra tablet cialis cost cheap cialis tablets cialis discount buy cialis in us online pharmacy cialis sale cialis cheap viagra on internet buy viagra in us discount viagra overnight delivery 25 mg viagra cheap price cialis buy cheapest viagra cheap viagra no rx viagra online stores order generic cialis viagra online review best price viagra cialis overnight delivery cialis pills cialis online review buy cialis overnight delivery order viagra overnight delivery buy viagra no rx cheapest sildenafil citrate viagra free delivery viagra sale 50mg viagra buy cialis without prescription cialis prices tablet cialis find viagra without prescription viagra order buy cheap viagra online viagra pills cialis in bangkok cialis without prescription order discount viagra buy viagra in canada viagra bangkok lowest price for viagra pharmacy online cheap cialis online viagra for sale cialis cheap price discount viagra online impotence cure cheap cialis internet approved viagra pharmacy cialis approved cheap viagra from canada 10mg cialis viagra prices cialis in us compare viagra prices cialis vs viagra viagra internet cheapest viagra online buy cheapest viagra online online cialis viagra side effects generic cialis online buy cheap viagra order cheap cialis online viagra online viagra malaysia buy cheapest viagra on line order cialis no prescription required cialis buy approved cialis pharmacy viagra in bangkok cheap viagra pharmacy order cialis no prescription lowest price viagra cialis sale order cialis online order cialis on internet order discount viagra online best price cialis cialis no rx viagra buy online online pharmacy viagra cheap cialis pill cheap viagra in canada cialis online without prescription cheap viagra from uk cheap viagra internet find no rx viagra buy sildenafil in spain order cheap cialis order discount cialis impotence drugs buy cialis no rx purchase cialis without prescription viagra overnight delivery viagra discount no rx viagra buy generic cialis viagra without a prescription buy viagra us discount viagra no rx viagra soft tab viagra cheap price cialis order purchase viagra online cialis generic viagra information discount cialis without prescription viagra buy drug buy cheap cialis internet cialis internet 20mg cialis buy viagra cialis in australia viagra australia viagra buy generic drugs viagra from india buy viagra online cheap buy cialis cialis from canada pfizer viagra price of cialis cialis uk viagra overnight buy generic viagra online buying viagra online buy cialis online viagra for order cheap viagra no prescription viagra sales generic cialis buy viagra from canada best price for cialis order cialis cialis online pharmacy buying cialis where to order cialis cialis india

Stephen Goldup/Univ. of Edinburgh

TAMING CHANCE. This molecule acts like the microscopic demons James Clerk Maxwell envisaged in the 19th century. Thermal or Brownian motion moves a ring-shaped molecule (blue) from one side to another of a dumbbell-shaped molecule (yellow). But a “gate” molecule (green) is designed to lock the ring molecule to just one side of the dumbbell. Brownian motion provides energy to move the ring, but the gate molecule steers it.

Occasionally, scientists stumble upon what seems to be a free lunch. But they’re not concerned about possibly violating the laws of economics. It would be much more shocking to break the laws of physics.

To physicists, the no-free-lunch rule is precious. One form of it is the first law of thermodynamics, which says that energy cannot be created from nothing. The second law of thermodynamics goes even further, declaring not only that lunches are never free but also that they come at some minimum price.

Nonetheless, some natural phenomena seem, at first glance, to violate the spirit, if not the letter, of those laws. Take living cells. In recent years, scientists have found that some molecular machines—proteins that perform crucial tasks of life, from shuttling molecules through membranes to reading information off of DNA—seem to move spontaneously. These machines are likely powered by the random motion of water molecules in their environment, the “thermal noise” that thermodynamics insists is not available for doing work.

While some researchers debate how such machines work without breaking physical laws, other scientists have begun to exploit similar phenomena to create artificial molecular motors—nanomachines that imitate nature by putting randomness to work. “The idea is, let’s take advantage of thermal noise, rather than fight against it,” says Dean Astumian, a theoretical chemist at the University of Maine in Orono.

Researchers have just begun to build artificial nanomachines that perform simple tasks, such as moving molecules, by steering random motion in one direction rather than another. In the Feb. 13 Journal of the American Chemical Society, a team led by David Leigh, a chemist at the University of Edinburgh in Scotland, describes the first molecule designed to use chemical energy to open or close a gate and allow one of its parts to randomly cross the gate in one direction, but not the other.

It’s very much like the task assigned to a hypothetical “demon” by the 19th-century Scottish physicist James Clerk Maxwell. His thought experiment was an early attempt to show how the second law defines group behavior and thus applies only to large numbers of particles.

(more…)

In the past few months, I have occasionally collaborated to Science News’ Book Reviews page. Here are the mini-reviews I’ve written so far.

The Archimedes Codex: How a Medieval Prayer Book Is Revealing the True Genius of Antiquity’s Greatest Scientist — Reviel Netz and William Noel

Some of the works of Archimedes—the Greek thinker and tinkerer who lived in 3rd-century B.C. Sicily and discovered the principle of buoyancy—survive only in a single 8th-century copy. As Netz and Noel recount, the manuscript was lost and found multiple times, erased and recycled into a prayer book by a 13th-century monk, and lived through fire, mold, and forgers who covered some of its pages with fake medieval paintings. In 1998, a collector bought the manuscript for $2 million and entrusted it to Noel, a curator at the Walters Art Museum in Baltimore. Using pioneering technology, researchers have managed to read most of the book’s content, allowing historians—including Netz—new glimpses into Archimedes’ genius. Da Capo, 2007, 320 p., color photos and b&w illus., hardcover, $27.50. [Also see: The 'Jurassic Park' of Manuscripts.]

ISBN: 030681580X

Apollo’s Fire: Igniting America’s Clean Energy Economy — Jay Inslee and Bracken Hendricks

The authors present a manifesto for the Apollo Alliance, a clean-energy advocacy organization that Inslee, a [democratic] congressman from Washington state, helped found and where Hendricks is a senior fellow. Greening the U.S. economy is not only necessary to save the environment and wean us off Middle Eastern oil, the authors write. It will also create millions of “green-collar” jobs, which will be held by everyone from engineers developing better solar panels to the workers who will install them. The book evokes the national focus on reaching the moon in the 1960s to advocate a comprehensive array of policy and technological solutions. It also aims to allay fears of losing jobs to new regulations and to defuse tensions between trade unions and environmentalists, two traditionally Democratic constituencies. Island Press, 2007, 416 p., b&w photos, hardcover, $25.95.

ISBN: 1597261750

Four Laws That Drive the Universe — Peter Atkins

Although it deals with seemingly familiar concepts such as temperature, thermodynamics ranks among the most conceptually treacherous branches of physics. Many students, for example, have puzzled over the definition of entropy, a measure of disorder. Atkins, a chemistry professor at the University of Oxford in England, guides the reader through the basics of thermodynamics in just over 120 pages by keeping a steady focus on the subject’s four fundamental laws. The book contains a modicum of formulas. And although it’s tersely written and titled like a popular-science book, Four Laws is a textbook both in essence and in structure. Atkins’ elegant exposition will appeal to the lay reader with a serious interest in physics. Oxford Univ. Press, 2007, 128 p., b&w illus., hardcover, $19.95.

ISBN: 0199232369

Auto Mania: Cars, Consumers, and the Environment — Tom McCarthy

As crude oil approaches $100 per barrel, wallet pain, more than any fears of global warming, may eventually lead Americans to reconsider their thirst for ever-heavier and ever-faster cars and trucks. Since Henry Ford’s invention of the mass-produced car, consumers have chosen what to drive based less on the environmental consequences—which include not just tailpipe emissions but the full product cycle, from mining to disposal—than on the allure of the car as a status symbol, McCarthy argues. He tells the story of a nation’s affair with four wheels and of how the car’s role as cultural icon has influenced its evolution. When considering the car’s impact on the environment, it is simplistic to blame it all on Detroit’s “big three” or the inadequacy of government regulations. One case in point, McCarthy writes, is the astonishing rise of the SUV, which took even car manufacturers by surprise. Yale Univ. Press, 2007, 368 p., b&w illus. and photos, hardcover, $32.50.

ISBN: 0300110383

Call it Murphy’s Law of knots: If something can get tangled up, it will. “Anything that’s long and flexible seems to somehow end up knotted,” says Andrew Belmonte, an applied mathematician at Pennsylvania State University in University Park. Belmonte has plenty of alarming anecdotal evidence. “It certainly happens in my house, with the cords of the venetian blind.” But the knot scourge is a global one, as anyone who owns a desktop computer can confirm after peeking at the mess of connection cables and power cords behind the desk.

Now, scientists think they may have found out how and why things find their way into knotty arrangements. By tumbling a string of rope inside a box, biophysicists Dorian Raymer and Douglas Smith have discovered that knots—even complex knots—form surprisingly fast and often. The string first coils up, and then its free ends swivel around the other coils, tracing a random path among them. That essentially makes the coils into a braid, producing knots, the scientists say.

The results’ relevance may go well beyond explaining the epidemic of tangled venetian blind cords. That’s because spontaneous knots seem to be prevalent in nature, especially in biological molecules. For example, knottiness may be crucial to the workings of certain proteins (see “Knots in Proteins”). And knots can randomly form in DNA, hampering duplication or gene expression—so much so that living cells deploy special knot-chopping enzymes.

(more…)

Slightly noisy signals can turn into rare large spikes in an optical fiber’s output, in much the same way as unpredictable weather conditions occasionally create monstrous, isolated oceanic waves, researchers have found.

The new technique for creating such “rogue waves” in the lab might help physicists understand them as a general phenomenon, in the hope of predicting the risks for vessels at sea.

A rogue wave will appear “at a random location, at a random time,” says Bahram Jalali, an electrical engineer at the University of California, Los Angeles (UCLA), who developed an interest in rogue waves while spending time on his 36-foot sailboat.

(Read the rest of my article on the Science News web site (password required))

Cover illustration by Anders Sandberg

This artist’s impression represents a view of a hyperbolic plane — the kind of beast that M. C. Escher loved to paint — projected on the surface of a sphere. Maldacena’s concept of the holographic universe translates a string theory living in hyperbolic space (the 3-D analogue of hyperbolic plane) into a theory of particles living on the surface of a sphere.

In a school of thought that teaches the existence of extra dimensions, Juan Maldacena may at first sound a little out of place.

String theory is physicists’ still-tentative strategy for reconciling Einstein’s theory of gravitation with quantum physics. Its premise is that the subatomic particles that roam our three-dimensional world are really infinitesimally thin strings vibrating in nine dimensions. According to Maldacena, however, the key to understanding string theory is not to add more dimensions but to cut their number down.

In his vision, the mathematical machinery of strings completely translates into a more ordinary quantum theory of particles, but one whose particles would live in a universe without gravity. Gravity would be replaced by forces similar to the nuclear forces that prevailed in the universe’s first instants. And this would be a universe with fewer dimensions than the realm inhabited by strings.

Just as a hologram creates the illusion of the third dimension by scattering light off a 2-D surface, gravity and the however many dimensions of space could be a higher-dimensional projection of a drama playing out in a flatter world.

(more…)