Monthly Archives: April 2017

Swarms of Cicada Drones Can Help to Research the Storm

Researchers are developing a tiny, gliding drone that can be dropped from airplanes to gather data directly from hurricanes, and these teensy machines share a name with a noisy spring-emerging insect.

Close-in Covert Autonomous Disposable Aircraft MK5, or CICADA, is “essentially a flying circuit board,” an autonomous, GPS-controlled drone so inexpensive to make that it would be considered disposable after a single use, representatives of the U.S. Naval Research Laboratory (NRL)said in a statement.

Unlike its noisy insect namesake, CICADA is exceedingly quiet — with no motor, it is silent and virtually undetectable in the air, NRL officials said in 2015. CICADA’s latest prototype, with a flattened wing and body design, make it easy to stack the individual “micro” aircraft, so that large numbers of CICADAs could be deployed at the same time from an airborne vehicle. This would enable scientists to distribute sensors and collect data across large areas of the sky, according to the NRL. [8 Ways Animal Flight Inspires Drone Designs]

The craft’s design lends it a glide ratio of 3.5 to 1, which means that it flies forward 3.5 feet (1.1 meters) for every foot (0.3 m) of descent, the NRL reported. Each CICADA “micro” drone weighs about 1.2 ounces (35 grams), and along with its circuit board and a sensor payload, they incorporate GPS technology to help them navigate to within 15 feet of a destination on the ground. Once on the ground, antennas built into their wings transmit the data back to a home base, reported IEEE Spectrum.

Production costs for CICADAs are about $250 per drone. The NRL is currently testing a delivery system capable of stacking 32 CICADAs into a single container — think of a tube of Pringles, except stuffed withminiature drones — and then dispatching them simultaneously, according to IEEE Spectrum.

Video demonstrations posted to YouTube on Tuesday (July 25) showed the drones performing in a series of tests, dropping from different altitudes in different locations, from as much as 8,000 feet (2,438 meters).

The tube and its drones could be carried and deployed by balloons, or from a manned or unmanned aircraft, or even guided missiles, NRL aerospace engineer Daniel J. Edwards said in a statement. After their airborne release, a group of drones, each with its own sensor and a different GPS-guided destination point, would sample data during descent — such as chemical or meteorological information — which could offer scientists a broader view of how hurricanes and tornadoes behave, Edwards said.

Self-Destructing Materials Can Make Vanishing Ink

Scientists have created a new material that simply self-destructs at a specific time. The process, which takes inspiration from the way life uses and reuses molecules, could pave the way for materials that don’t need to be recycled, but instead would simply disintegrate at an appointed time. The finding could lead to various products, including structures for drug delivery, transplant anchors and vanishing ink.

The secret behind these self-destructing molecules is that they would require a tiny input of energy to stay in their useful form — without it, they … poof.

“They are materials that don’t want to be that type of material. They’d rather be the original building blocks,” said study co-author Job Boekhoven, a chemist at the Technical University of Munich in Germany. “They’d rather fall apart and be nothing.” [Biomimicry: 7 Cool Technologies Inspired by Nature]

When humans are done with an object, they toss it in a landfill, where it will very, very slowly break down; or they burn it to ash; or they recycle its materials by extensively processing them and then returning them to the supply chain. All these methods waste a tremendous amount of either materials or energy.

But life doesn’t waste molecules in the same way, mainly because of how it uses chemical bonds, Boekhoven said.

For instance, most human-made solids are created using a kind of molecular marriage called covalent bonding, in which atoms share electrons. These incredibly strong bonds are hard to break up. Think of aplastic polymer made by heating up the basic building blocks from a petroleum product. They form tough carbon bonds that bacteria are not able to break, which is why plastics don’t biodegrade, Live Science previously reported.

But life relies on what are more like casual hookups: much weaker molecular interactions such as ionic, van der Waals or hydrogen bonding, Boekhoven said. For instance, hydrogen bonding, the kind ofelectrostatic attraction found in water in which the positive and negative ends of molecules align, is 10 times weaker than covalent bonding, in which atoms share electrons. And van der Waals forces, in which the ever-shifting electron clouds of atoms slightly rearrange themselves to reduce repulsion or strengthen attraction, vanish at larger distances.

Life also relies on another key factor that is vital to the new vanishing molecules: The molecular structures life uses are always “out ofequilibrium,” meaning they require a constant influx of energy to keep functioning. Without that extra energy (from food, for example), these molecules will eventually dissociate on their own and return to a simpler state.

“A cell constantly needs nutrients and energy,” Boekhoven told Live Science. “Otherwise, it would just fall apart to its simple building blocks.”

One benefit of life’s approach is that it makes it easy to quickly reassemble the more complex structure with a little input of energy, meaning life-based molecules are essentially self-healing, Boekhoven said.

In the current work, Boekhoven and colleagues decided to take a page from life’s way of assembling materials. To do so, the researchers created a few different types of materials that require energy input to stay in their current forms, which the scientists call supramolecular molecules.

The first was a simple colloid made of tiny beads, each of which are just 1 percent as big as the diameter of a human hair, Boekhoven said. As fuel is added, the miniature beads assemble like a string of pearls, and they can be tuned to assemble and disassemble in a certain order and at certain times. Boekhoven said he envisions these materials being used to deliver drugs. For instance, certain drugs need to bypass stomach acid, so if they are timed to disassemble only after they’ve passed into the gut, they could protect drugs until they reach the desired location, Boekhoven said.

The researchers also tested a fluffy crystalline material that is normally see-through but becomes cloudy and opaque when a fuel is poured on top of them. As the fuel is used up, dark spots become clear again. The team envisions this material being used as a completely erasable ink, the researchers reported July 18 in the journal Nature Communications.

“So, you can create a temporary message that erases with a predefined lifetime,” Boekhoven said. A material like that could dramatically reduce the use of ordinary paper in things like bills, tickets and receipts, he said.

Yet another material is formed from long fibers that self-assemble to form structures that could one day be used to anchor a tissue transplant in place until the body can take over; the material would then vanish, the researchers said.

If these materials self-assemble and degrade, and they require energy input to exist, then are they “living” in some sense?

Right now, none of these materials really have any of life’s properties, Boekhoven said. But researchers in the field are beginning to ask what the necessary ingredients are for making a truly self-replicating particle, Boekhoven said.

How Can Futuristic Laser Weapons US Navy Use Old-School Phone Tech

The U.S. Navy’s recent demonstration of its new laser weapon, designed to blast enemy drones out of the sky, proves that these systems no longer solely exist in the world of science fiction. But how do these so-called directed-energy weapons work?

The idea for laser weapons has been around for at least a century; the writer H.G. Wells even imagined “heat rays” in his 1897 novel “War of the Worlds.” Lasers, though, are a demonstration of several technologies and even physics that didn’t exist or wasn’t known until the 1960s — and in some cases, later than that.

In part, the initial drive to build laser weapons wasn’t to make ray guns — it was to help people make phone calls. It wasn’t until fiber optics and cheap laser diodes became available that this technology could be used to build weapons, according to experts. [7 Technologies That Transformed Warfare]

“We could build powerful lasers in the past, but they weren’t small enough or powerful enough to be tactically deployed,” said Robert Afzal, a senior fellow in laser and sensor systems at Lockheed Martin, one of several companies that has been developing laser weapons for the military. “With high-powered, fiber-optic laser technology, we can now build a laser powerful and small enough for a tactical vehicle.”

The laser system being developed at Lockheed isn’t the same one that was demonstrated last month by the U.S. Navy, but the physics and engineering are similar, Afzal told Live Science.

The word “laser” is actually an abbreviation for “light amplification by stimulated emission of radiation.” To make a laser, you need a lasing medium — some material that emits light when it is stimulated by energy. Further, that light needs to be a single wavelength, and all thelight waves need to be in step — a state called coherence.

A neon light bulb generates light of specific wavelengths, but those waves aren’t all in step; they’re jumbled together, with the crests and troughs at different places. This makes it harder to focus the light into a beam that doesn’t disperse over long distances. It also means less energy gets delivered to anything illuminated by that light.

Coherent light waves can be more focused. In other words, the light waves in a laser beam spread out much less than those in a flashlight beam do, directing more of its energy into a small spot.

The first laser beams in the 1960s were generated with ruby crystals that were pumped with light from a powerful type of flash lamp. The crystal was called the gain medium.

The intense light excited the atoms in the crystal, which then generated the photons, or packets of light, for the laser. A mirror was at each end of the crystal, and one of the mirrors was transparent. The light would be reflected from one side and come out the transparent side.

More modern lasers use gases as the gain medium, such as carbon dioxide, helium or neon. They all produce lasers of different wavelengths for different applications. Carbon-dioxide lasers emit infrared light, and they are often used as cutting tools. [Science Fact or Fiction? The Plausibility of 10 Sci-Fi Concepts]

Later the chemical laser was invented, but that wasn’t going to work for shipboard weapons. “The old chemical lasers took up a lot of volume,” said Mark Skinner, vice president of directed energy at Northrop Grumman Aerospace Systems. “They also sometimes used toxic chemicals.” For example, a hydrogen fluoride lasers, first demonstrated in 1969, can deliver high-powered beams but the hydrogen fluoride is dangerous and difficult to handle.

The laser diode was a big innovation; though they were first demonstrated in the 1960s, it wasn’t until the 1970s that semiconductor lasers were built that could operate continuously at room temperature. Earlier, in 1966, Charles K. Kao (who would go on to win a Nobel Prize in Physics in 2009) discovered how to transmit light over optical fibers, which meant that lasers could be used as a means of communication. Then, the development of cheap diode lasers enabled the building of devices such as CD players and laser communication arrays.

“Really, we put together two revolutions: fiber-optic telecommunications and wave-division multiplexing,” Afzal said. Wave-division multiplexing (WDM) is a technique that combines lasers of different wavelengths onto a single fiber, which enables more power to be pumped through a fiber-optic strand. Originally applied to communications, it became a go-to technology for laser weapons as well, he said.

But laser weapons require more than simply making laser light — they need to transmit the light to a target and do so with enough energy to inflict damage. Laser power is usually measured in watts. The power of a laser pointer can be measured in milliwatts, but that’s still enough to injure a person’s eyes. The power of industrial laser cutters is in the kilowatt range. The military needs lasers that have a much more powerful range than that — in the tens of kilowatts, at least. [Flying Saucers to Mind Control: 7 Declassified Military & CIA Secrets]

The U.S. Navy’s new laser weapon, which is currently deployed on the USS Ponce — an amphibious transport ship — is reportedly a 33-kilowatt laser, and it can fire several beams that add up to 100 kilowatts. The Navy said in January that it plans to test a 150-kilowatt version within a year. (A Navy spokesman said he couldn’t reveal how powerful the laser actually is.)

The reason for the high power is that even though lasers are focused to a narrow point, their beams still spread out over long distances, and that cuts down the energy that gets delivered to the target. A laser damages its target because the energy from the light heats up the material it hits. As such, the beam has to stay on a target for a certain period of time (more power means less time and thus a more effective weapon). A video released to CNN shows the Navy’s Laser Weapons System (LaWS) trained on a target for about 1 or 2 seconds, but none of these specifications have been publicly released yet.

The LaWS aboard the USS Ponce is a fiber-optic laser, and it combines beams to increase the power. While fans of “Star Wars” may recall the image of several separate beams joining together after they’re emitted from the Death Star, real combined-beam lasers don’t work like that. Instead, they use fiber optics to generate the beams, and then those beams are combined using a prism-like setup of lenses.

“Think of that cover of [the Pink Floyd album] ‘Dark Side of the Moon,'” Afzal said. “You have a prism that combines several beams into one.”

Another advantage of fiber optics, Afzal said, is that the beams are more “perfect.” This means there is less diffraction, or spreading out of the light, than there is with a traditional lens (early lasers had beams focused by lenses, and laser pointers still do this).

One of the biggest issues with developing laser guns was figuring out how to power them. Thirty kilowatts over 1 second is enough to light up a neighborhood (the average home in the U.S. uses about 10 kilowatt-hours in a year). This means that any boat using a laser weapon has to have a power plant that’s robust enough to handle it. The USS Ponce demonstration showed that it could handle the power load.

The advantage of lasers, and the reason the military is interested in them, is speed. A laser beam travels at the speed of light. Practically speaking, when a laser weapon is aimed at something, it will hit instantly. There’s no need to point the weapon slightly ahead of where the target is moving, as would need to be done if the military were trying to shoot down a projectile. And contrary to what’s depicted in movies, there’s no way to see a laser beam unless there’s something scattering the light. If the beam is visible, it would simply appear to be instantly “on,” just like a searchlight.

Lasers are also cheap to use, according to the Navy, because the only cost is power. This means that once the weapon is built, the price per shot goes down — a laser never runs out of ammunition. Missiles, on the other hand, can cost thousands of dollars each, Skinner noted.

Still, there are some disadvantages to using lasers as weapons. Subrata Ghoshroy, a research affiliate at MIT who worked on early laser weapons in the 1980s, noted that weather can be a problem. Laser beams are made of light, which means fog and other inclement weather will scatter that light. Range would be reduced as a result, along with the energy directed on the target.

Heat is also a factor. “Thermal management is a horrendous problem,” Ghoshroy said. The reason is that all those kilowatts through a diode heat it up, and eventually, the beam quality degrades. It was not clear, he said, how often the USS Ponce’s laser could fire or how long it would last before it runs into problems.

Afzal said the weather issue is common to many weapons systems, so lasers aren’t unique in that sense. Fog, for example, would stop many kinds of missile launchers or guns. “If you can see it, you can engage it,” he said.

Does Biology Explain Gender Disparity in Tech?

A Google employee recently published an anti-diversity manifesto on an internal discussion board that has gone viral and stirred furious debate both inside and outside the company.

In the essay, James Damore claimed that differences in the number of women and men in tech companies such as Google can be largely explained by biological differences, rather than sexism. As a result, some diversity efforts aimed at increasing the representation of women and other minorities are discriminatory against men, he argued. (After the memo went public, Google fired Damore for perpetuating gender stereotypes, Reuters reported.)

But what does science have to say about the biological differences between men and women, and how do they affect the gender gap in tech?

“It would be foolish to say there are no biological differences between men and women,” said Margaret McCarthy, a neuroscientist at the University of Maryland who studies gender differences in the brain. “Sex is the most potent of all biological variables.” [Men vs. Women: Our Key Physical Differences Explained]

However, pinning the lack of women in tech to biological differences is on much shakier ground, when socialization or sexism are much likelier explanations, several experts told Live Science.

In Damore’s manifesto, he claimed that, compared with men, women on average are more attracted to aesthetics than to ideas, more empathizing than systematic and more extroverted than introverted, but less assertive and less competitive. As a result, he said, women may have more difficulty negotiating higher salaries, speaking up or asking for raises.

He also claimed that women exhibited higher neuroticism, which is manifested in lower stress tolerance and higher anxiety, and that women are less willing to work the long hours necessary to achieve high-paying, high-status jobs. In another section of the manifesto, he said people on the ideological left deny biological differences when they are tied to IQand sex differences.

It turns out, there are extensive neuroanatomical differences between men’s brains and women’s brains on average, said Larry Cahill, a neurobiologist at the University of California, Irvine. This shouldn’t be surprising; after all, humans are mammals, and mammals exhibit extensive sex-based differences in brain chemistry, anatomy, genetics and function, Cahill told Live Science.

McCarthy agreed.

“We are biologically different,” McCarthy told Live Science. “It would be crazy to say that difference in biology doesn’t to some degree extend to our brains. To think that we have somehow escaped millions of years of evolution because we’re modern humans, I think, is just folly.”

For instance, women on average have more gray matter, the computational workhorse of the brain, while men have more white matter, which connects brain cells in different regions of the gray matter.Men and women also have different connective networks between brain cells, on average, according to a 2013 study in the journal Proceedings of the National Academy of Sciences. What’s more, men’s brains tend to be larger than women’s. And sex hormones such as testosterone and estrogen, which vary dramatically between men and women, also bind differently to receptors in the brain. [10 Surprising Facts About a Man’s Brain]

However, these average differences do not make it possible to type individual brains: A 2015 study in the same journal found it was impossible to categorize most brains as stereotypically male or female based on gray matter in several brain regions.

“Gender differences, small or large, do not ‘add up’ to create two types of people,” said Daphna Joel, a neuroscientist at Tel Aviv University in Israel who was one of the authors of the 2015 study. “Rather, each person has a unique mosaic of feminine (that is, more common in women than in men) and masculine (that is, more common in men than in women) psychological characteristics.”

Once scientists make the leap from brain anatomy to function, the connection gets even shakier. For instance, bird brains are smaller than mammalian brains, and they’re wired very differently. Yet many birds can tackle brainy feats that stymie the smartest nonhuman mammals. Clearly, brain anatomy does not reveal the whole story, McCarthy said. [Are Big Brains Smarter?]

What’s more, many differences in the structure of men’s brains versus women’s brains may actually counteract gender differences in behavior, a 2004 study in the journal Endocrinology found. For instance, women inherit two X chromosomes, while men inherit an X and a Y. But in women’s brains, one of the X chromosomes is almost completely silenced to keep them from getting a double dose of gene expression, meaning that men’s and women’s brains express roughly the same number of X chromosome genes — even though, genetically, they have this chromosome difference.

Still, there’s no reason to discount the possibility that anatomical or biological differences translate to behavioral differences, Cahill told Live Science.

“Is it inherently plausible that biologically based sex-related influences affect all aspects of human behavior, including careers people choose?” Cahill asked. “The answer is yes.”

Still, many of the average differences between men and women that were described in the manifesto are either small or near zero, according to a 2005 study in the journal American Psychologist. Some, if not all, of the average differences could be due to socialization rather than biology, several experts said.

For instance, across cultures, men tend to be better at rotating objects in their mind than women are. However, in India, tribal women in matrilineal societies who hold the purse strings perform better at this task than women in nearby, genetically similar tribes, which are patrilineal. Education also dramatically shrinks this gap in spatial abilities, the researchers found.

In the United States, men outperform women on the math SAT, while in Japan, men and women perform equally well on the math portion of this standardized test — and outperform both their male and female American counterparts, McCarthy said. Meanwhile, in some Nordic countries, women outperform men on the math portion of the SAT.

Similar disparities in science versus reading abilities exist across countries, said Bernd Frick, a professor of organizational economics at Paderborn University in Germany. [6 Myths About Girls and Science]

“Girls are told that reading abilities are important. Boys are told that sciences are important, and you see that reflected in standardized tests with young kids ages 8 to 9 or 10 to 12,” Frick told Live Science.

However, more patriarchal societies show a much larger gap in these test scores, while egalitarian cultures show only a tiny gap, he added. That suggests that culture, rather than brain differences, explains most of the gap, he added.

As for women’s versus men’s average intelligence (IQ), there is no average difference.

“That has been shown over and over and over with millions and millions of data points,” McCarthy said.

Women do tend to exhibit higher rates of diagnosis with certain types of neuropsychiatric diseases, such as major depressive disorder, anxiety and obsessive compulsive disorder, McCarthy said. However, the difference in the gender ratio for anxiety is quite small compared with differences for other diseases such as anorexia nervosa or autism. Men are also less likely to seek out diagnoses and more likely to self-medicate with alcohol and drugs, meaning at least some of the gender difference in the rates of depression or anxiety could be due to underdiagnosis in men, not a differential response to stress, she added. [7 Ways Depression Differs in Men and Women]

“Is the gender difference in the level of stress you’re manifesting, or is it that you’re willing to admit you’re feeling that stress and anxiety?” McCarthy asked. “These are very complex questions [that] we don’t know the answer for.”

Also, gender differences may wax or wane through the life span, making it difficult to tease out the effects of socialization versus biology. For instance, young girls tend to start out being much more aggressive and assertive but become less so by the adolescent years.

“Is it because they are punished for getting out of their ‘gender lane,’ or is it because they go through puberty?” McCarthy said. Right now, there’s no way to know, she said.

Other work has shown that women are less competitive than men on average. However, a 2011 study of ultramarathoners, published in the Journal of Sports Economics, showed that as societies become more egalitarian and the prize money women compete for approaches the pots for men, the competitiveness gap disappears.

“So it’s a matter of culture,” Frick said.

The manifesto goes way out on a limb, however, when it aims to explain the gender gap in tech to biology when other factors such as sexism or outmoded family structures clearly play a role, McCarthy said.

For instance, several studies have shown that a powerful way to attract more women to leadership positions is to have more women in leadership roles, McCarthy said. So the dearth of senior women in tech could lead to a vicious cycle of under-representation, she added.

What’s more, women do not inherently want to work fewer hours. Rather, many are expected to shoulder a second shift of childcare and chores when they get home, McCarthy said.

“They have two jobs,” McCarthy said.

And sexism in the tech world isn’t benign either, Cahill said.

“I always hear about a bro cultulre [in tech],” Cahill said. “It’s probably the case that the average woman will chafe more at the average bro culture than the average man.”

What’s more, no studies have shown that the skills and personality traitsneeded for tech jobs are uniquely male. For instance, no studies suggest that being agreeable, empathetic or extroverted (the traits Damore ascribed to women) are liabilities for those in the tech field, McCarthy said.

“If Google needed only people with only extremely masculine characteristics, then there would be more suitable male candidates than female candidates,” Joel said. “But even in the relatively narrow field of tech, there are many different combinations of characteristics (some more common in women and some more common in men) that fit, so sex differences in the prevalence of these mosaics is unlikely to explain the gender gap in tech.”