Fiddler crabs take carefully calibrated steps to find their way home, according to a new study in Current Biology [subscription required]. Scientists testing the tiny crustaceans’ homing skills found that both the length and number of their strides were guided by some sort of internal mileage counter. This allows them to plot a direct path back to their sandy burrows even if the burrows are out of sight. “We were able to measure every step by every leg of every animal in this experiment, and since these are eight-legged animals, that’s a lot,” [Scientific American] says co-author John E. Layne.
Many animals appear to have built-in GPS systems, although exactly how they function is not well-understood. Birds and sea turtles may use the position of the stars and the earth’s magnetic field to navigate. The honeybee has been shown to use the flow of the passing landscape across its field of vision. Some other animals may be able to gauge linear acceleration and use that to determine distance [The New York Times]. The way animals keep track of their movements and the distance they’ve traveled is known as path integration.
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In another step forward for biofuels, a commercial jet took to the skies yesterday over New Zealand to test a new jet fuel blend that uses oil from the oily jatropha plant. Air New Zealand announced that a Boeing 747 plane flew for about two hours yesterday, running on a 50/50 blend of conventional jet fuel and biofuel. Jatropha—a weedy bush from Africa that produces seeds rich in oil—was selected because it is not a food crop and can be grown on land unsuitable for food production. The roughly three tons of liquid jatropha biofuel came from plants grown in India, Malawi, Mozambique and Tanzania, the airline says [Scientific American].
Air New Zealand is the second airline to test-fly a jet plane powered by biofuel. The first was Virgin Atlantic Airways, which in February flew a Boeing 747-400 from London to Amsterdam with one of its four tanks filled with jet fuel containing a 20 percent blend of biofuel made of coconut and babbasu oil [Greentech Media]. Meanwhile, other airlines are developing jet fuels derived from algae or oilseed plants: Continental Airlines and Japan Airlines both have test flights scheduled for January.
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Spikes in blood sugar levels seem to be linked to memory problems, and may be a major factor in the normal memory and cognitive problems that crop up as people age, according to a new study. People’s ability to regulate blood sugar begins to deteriorate by their third or fourth decade and continues to decline, so older people are more prone to these sugar spikes. “This would suggest that anything to improve regulation of blood glucose would potentially be a way to ameliorate age-related memory decline,” said senior study author Dr. Scott Small…. The findings may also help explain why people who exercise don’t have as many cognitive problems as they age: Exercise helps stabilize blood glucose levels [HealthDay News].
The findings have important implications for the increasing number of overweight children who are at risk of diabetes, commented neuroscientist Bruce McEwen. “When we think about diabetes, we think about heart disease and all the consequences for the rest of the body, but we usually don’t think about the brain,” he said. “This is something we’ve got to be really worried about. We need to think about their ultimate risks not only for cardiovascular disease and metabolic disorders, but also about their cognitive skills, and whether they will be able to keep up with the demands of education and a fast-paced complex society. That’s the part that scares the heck out of me” [The New York Times].
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An exhaustive report on what happened in the crew cabin during the final moments before the space shuttle Columbia broke up over Texas in 2003 found numerous equipment flaws that failed to protect the astronauts from the extreme conditions they were abruptly exposed to during the disaster. But in somber tones, NASA‘s report also acknowledged that “the breakup of the crew module … was not survivable by any currently existing capability” [CNN].
The mission was doomed when a chunk of foam broke away from an external fuel tank and struck the shuttle’s left wing during its launch; 15 days later, during reentry to the Earth’s atmosphere, superheated gases poured into the hole created and melted the shuttle’s structure. From the crew’s perspective, the shift from what appeared to be a normal descent on 1 February 2003, into disaster happened so fast that the astronauts didn’t even have time to close the visors on their helmets…. The crew cabin broke away from the ship and started spinning rapidly. Analysis of the wreckage indicated the crew members had flipped cockpit switches in response to alarms that were sounding. The astronauts had also reset the shuttle’s autopilot system, the report said [New Scientist].
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In a vote of confidence for the fledgling commercial space industry, NASA has awarded contracts that could total $3.5 billion to two companies that plan to build rockets and ferry supplies to the International Space Station. The companies, SpaceX and Orbital Sciences Corporation, could begin launches as soon as 2010 to help fill the gap between the space shuttle‘s expected retirement and the introduction of NASA’s next-generation rocket, the Ares I. The companies beat out traditional NASA contractors like Boeing and Lockheed Martin to snag the contracts.
Experts say that giving a contract to the young company SpaceX is a particularly bold bet. SpaceX, the plan’s linchpin because it is intended to begin the service, carries a relatively short pedigree as a government contractor and can point to only one successful launch, after three failures, of a smaller version of its Falcon rocket intended to supply the space station. Orbital Sciences is an established, midsize aerospace contractor but lacks a proven track record for the revamped version of the Taurus rocket it will use to supply the station [The Wall Street Journal, subscription required].
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Naturally lush lashes can be yours within 16 weeks, claims the drug company Allergan, which has received approval from the Food and Drug Administration (FDA) for Latisse, the first ever eyelash-enhancing medication. According to the company, clinical trials show that daily dabs of Latisse on the edges of eyelids produce longer, thicker lashes, although mild side effects are possible. Allergan plans to start selling prescription-only Latisse by the end of March.
The eyelash-enhancing ingredient in Latisse is bimatoprost, a compound derived from fatty acids that bind to receptors in the eyelashes that may be involved in the development and re-growth of hair follicles. Allergan has used bimatoprost since 2001 in Lumigan, an Rx eye drop that lowers eye pressure in people with glaucoma [Scientific American]. Drugmakers stumbled upon the idea for Latisse when doctors and patients noticed lusher lashes on glaucoma patients taking Lumigan. Soon after, some doctors began writing Lumigan prescriptions for cosmetic patients, and competitors raced to create eyelash products that used bimatoprost or similar ingredients [The Wall Street Journal, subscription required]. Allergan, which also produces Botox, has since sued 11 companies for patent infringement for using bimatopost to promote lash growth.
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Gay young adults who were rejected by their families when they came out as teenagers are much more likely to attempt suicide, have unprotected sex, and have problems with drug use and depression, according to a new study. The findings are based on surveys of 224 gay, lesbian, bisexual and transgender adults in California who ranged in age from 21 to 25. Gay Latinos were most likely to experience a poor reception from their parents, and had the highest rates of risk factors for HIV and mental health problems, according to the research [Scientific American].
The findings, published in the journal Pediatrics [subscription required], don’t prove that a family’s negative reaction to a child’s sexuality directly causes problems later in life. But it’s clear that “there’s a connection between how families treat gay and lesbian children and their mental and physical health” [HealthDay News] said social worker Caitlin Ryan, the study’s lead author. She found that teenagers who were rejected by their families were eight times as likely to attempt suicide, six times as likely to report serious depression, and three times as likely to have unprotected sex and use drugs.
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Natural disasters took a deadly toll in 2008, killing more than 220,000 people and causing a total of $200 billion in damages–a 50 percent increase in costs over 2007. A new report sums up the damages wrought this year by weather and geology; the deadliest disaster was the cyclone that battered Myanmar in May, killing an estimated 130,000 people and causing losses of $4 billion, and the costliest was the earthquake that struck China’s Sichuan province, killing an estimated 70,000 and causing losses of $85 billion.
The new figures come from an annual assessment of global damages by the reinsurance giant Munich Re, which offers backup policies to companies writing primary insurance policies. Reinsurance helps spread risk so that the system can handle large losses from natural disasters [AP]. Munich Re has a financial interest in understanding global weather patterns, and board member Torsten Jeworrek says the uptick in losses from natural disasters is another indication that global warming is already having widespread effects. “Climate change has already started and is very probably contributing to increasingly frequent weather extremes and ensuing natural catastrophes,” he said [BBC News].
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A synthetic material that mimics the qualities of an iridescent opal may have wide-reaching technological applications, its creators say. With the application of an electric current the material can rapidly change to any color of the spectrum, and the developers, who said they’re ready to sell the technology today, added that their ‘photonic ink’ (P-Ink) material could soon be used in electronic books or advertising displays [ZDNet].
The synthetic material can be likened to an opal, a mineral that owes its variety of colours to its layered structure: regions with a high refractive index, in which light travels slowly, are interleaved with regions with a low refractive index. Light waves with a wavelength – or colour – similar to that of the space between layers are scattered in a way that gives opal its iridescent sheen [New Scientist]. The synthetic material has a similarly layered structure, but with the addition of a little voltage the space between the layers swells or shrinks, allowing for fine-tuned control of what color of light the material scatters.
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The facial expressions that register human joy and disappointment may be hard-wired into our brains, according to a new study. To probe the origins of smiles and scowls, psychologist David Matsumoto and his team compared 4,800 photographs, capturing the expressions of sighted and blind judo athletes at medal ceremonies at the 2004 Olympic and Paralympic Games. In each case, the faces of gold and silver medal winning athletes were scrutinised [BBC News].
The researchers found that both the blind and sighted gold medal winners produced joyful smiles known as Duchenne smiles, in which the cheek muscles rise and the muscles around the eyes crease. In contrast, both blind and sighted silver medal winners initially showed sadness, with their mouths turned down, but put on “social smiles” that use only the mouth muscles when they received their medals.
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For the first time, scientists have derived and cultured embryonic stem (ES) cells from rats, paving the way for genetically engineered rats that would more accurately model some human diseases than the currently available genetically engineered mice. Two collaborating teams developed a new approach to derive the ES cells, using a new cocktail of molecules to protect their precious pluripotency, the ability to differentiate into any type of cell. “This is a major development in stem cell research because we know that rats are much more closely related to humans than mice in many aspects of biology. The research direction of many labs around the world will change because of the availability of rat ES cells,” says Qilong Ying [Xinhua], who led one of the teams.
ES cells from mice have been available since 1981, and different researchers have created hundreds of different strains of “knock-out” mice—ones raised from ES cells in which certain genes are silenced to make apparent the genes’ functions. With mice, ES cells were grown with a mixture of growth signals to make them divide without differentiating. But transferring the same technique to rats and other mammals proved surprisingly difficult. To the great frustration of researchers, stem cells isolated from rat embryos and cultured with growth signals would quickly lose their pluripotency. The new strategy, reported in two studies in Cell [subscription required], involves growing the ES cells in a mixture of three key molecules that block the signals that normally induce differentiation. “Our discovery was that if you want to maintain cells in the undifferentiated state, you must block signals, not activate them,” says Ying… By repressing differentiation, the researchers could hold the cells in what they call a “ground state,” a blank slate ready to turn into any tissue in the body [Science News].
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In several years police officers may have laser or microwave guns to point at miscreants, according to the Justice Department’s research and development agency. These nonlethal weapons build on knowledge gained from the Pentagon’s controversial Active Denial System (ADS) – first demonstrated in public last year, which uses a 2-metre-[wide] beam of short microwaves to heat up the outer layer of a person’s skin and cause pain. Like the ADS, the new portable devices will also heat the skin, but will have beams only a few centimetres across. They are designed to elicit what the Pentagon calls a “repel response” – a strong urge to escape from the beam [New Scientist]. But the idea of giving cops a tool capable of instantly inflicting pain from across a town square is raising protests from human rights advocates.
The Justice Department is working on two separate weapons. One, the Personnel Halting and Stimulation Response, or PHaSR, uses an infra-red laser to heat a patch of skin about 4 inches in diameter, and pairs that heat with another bright laser that dazzles the eyes. The PHaSR looks like a bulky rifle, and law enforcement officials say that a cheap, portable version could be very useful to police and prison guards. Sid Heal, formerly a Commander in the Los Angeles Sheriff’s Department (and before that a Marine) , has long been an advocate of non-lethal weapons and thinks the new devices might have potential. “Needless to say, the “market” is so vacant with alternatives that ANYTHING is going to be appealing at this point” [Wired News], says Heal.
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When a honeybee is given a dose of cocaine, it gets overexcited about poor-quality food and performs overenthusiastic dances to communicate with its hivemates, according to an odd new study that got bees hooked on drugs. The research found similarities between honey bees and humans, in that they are both are driven by rewards and both have their judgment altered by cocaine. “This is the first time that it’s been shown that cocaine has been rewarding to an insect” [Reuters], says study coauthor Andrew Barron.
After a honeybee has been out foraging for food, it returns to the hive and tells the other bees what it found by means of a “waggle dance” that describes the location and quality of the food source. But after dabbing low doses of cocaine on the bees’ backs before they went out, the researchers observed that when they returned they were more likely to dance for their nest mates, and performed particularly vigorous routines explaining where the food was located [The Guardian]. They performed these exuberant dances even when the food source that the researchers provided was a weak sugar water solution that didn’t merit the hive’s attention.
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As the year 2008 draws to a close, the world’s timekeepers are giving us a little extra time to wrap up loose ends: They’re giving us one extra second, to be precise. The “leap second” must be added to keep atomic clocks ticking along in time to the planet’s rotation. So at precisely 23:59:60 at Greenwich, England, on New Year’s Eve, there will be a one-second void before the onset of midnight and the start of the New Year…. By the time the transition from 2008 to 2009 arrives in North America the Leap Second will have already been inserted into the world’s timescale [SPACE.com].
The adjustment is necessary because we have two different ways of measuring time. Traditionally, humankind has reckoned time by the spin of the Earth and its orbit around the sun. Under this astronomical arrangement, a second is one-86,400th of our planet’s daily rotation. But because of tidal friction and other natural phenomena, that rotation is slowing down by about two-thousandths of a second a day. Since the 1950s, however, atomic clocks — which are based on the unwavering motions of cesium atoms — have made it possible to measure time far more accurately, to within a billionth of a second a day [The New York Times]. To keep the two measurement systems in alignment, the atomic clocks have to add an extra second about every 500 days.
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In the western world, marriage between first cousins is labeled incest or inbreeding, and in the United States the practice is banned or restricted in 31 states. But a new essay argues that such laws are based on an outdated notion of the genetic risks involved in cousins marrying and reproducing. [T]hose laws “seem ill-advised” and “should be repealed,” a geneticist and medical historian write…. “Neither the scientific nor social assumptions that informed them are any longer defensible” [Scientific American].
First cousins share about an eighth of their genes, and are therefore more likely to receive two copies of some recessive gene that poses health problems. Scientists had assumed that the children of first cousins would therefore be more likely to be born with birth defects. But coauthor Hamish Spencer writes that the risk of congenital defects is about 2 per cent higher than average for babies born to first-cousin marriages – with the infant mortality about 4.4 per cent higher – which is on a par with the risk to babies born to women over 40. “Women over the age of 40 have a similar risk of having children with birth defects and no one is suggesting they should be prevented from reproducing,” said Professor Spencer [The Independent].
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