Dolphins do not whistle, but instead "talk" to each other using a process very similar to the way that humans communicate, according to a new study.

While many dolphin calls sound like whistles, the study found the sounds are produced by tissue vibrations analogous to the operation of vocal folds by humans and many other land-based animals.

Communicating similar to the way that humans do solves what would otherwise be a major dolphin problem.

"When we or animals are whistling, the tune is defined by the resonance frequency of some air cavity," said Peter Madsen, lead author of the research appearing in Royal Society Biology Letters. "The problem is that when dolphins dive, their air cavities are compressed due to the increasing ambient pressure, which means that they would produce a higher and higher pitch the deeper they dive if they actually whistle."

Madsen, a researcher in the Department of Biological Sciences at Aarhus University, and his team studied how dolphins communicate by digitizing and reanalyzing recordings made in 1977 of a 12-year-old male bottlenose dolphin.

A blind cave fish that has spent millions of years underground isolated from evidence of day and night still has a working biological clock, albeit an unusually distorted one, scientists find.

This research could yield new clues on how such clocks might work in animals in general, researchers added.

Internal clocks known as circadian rhythms help animals, plants and other life to adapt their daily activities to the cycle of day and night. These clocks do not always follow a precise 24-hour schedule, so to keep synchronized with the natural world, they get reset on a daily basis by signals such as daylight.

One question circadian clocks bring to mind is whether and how those creatures that live in perpetual darkness still keep time. For instance, about 50 fish species worldwide have evolved to live without sunlight in caves, many times losing their eyes.

"Cave fish give us a unique opportunity to understand how profoundly sunlight has influenced our evolution," said researcher Cristiano Bertolucci, a chronobiologist at the University of Ferrara in Italy.

Scientists are starting to consider the notion that whales might have a pretty cool culture. It looks as though Herman Melville picked the right hero for his epic novel.

"Whales are pretty hard to study, but evidence is coming up from quite a number of species that in a whole range of ways, they're learning things from each other and they're passing it on to other whales, and that's culture," says Hal Whitehead, biology professor at Dalhousie University in Nova Scotia, Canada. Whitehead says whales don't have opposable thumbs, so they can't craft material objects to pass on through the generations: "Whale cultures are in their minds and not in the things that they make."

"Whale culture has, like human culture, a range of types and styles," says Whitehead. "At one end, there are the fast moving what might be called 'pop' cultures, such as when male Humpback whales sing songs to attract females or ward off other males. "These songs evolve, so that at the beginning of the breeding season they're all singing one song and then it's changed a bit by the end," says Whitehead. "And after a couple of years they're singing a totally different song."

But other whale languages are more constant and enduring. The dialects of killer whales, which travel in large extended-family groups called pods, "seem to change much more slowly and to be linked to particular social structures," says Whitehead. "A particular pod will have its own dialect, and that dialect will be similar to pods which are the members of the same clan, and clans will have dialects which are different from one another - just as humans from different parts of the same country may sound a bit different, but humans from different countries may be totally unintelligible to each other," says Whitehead. And these dialects will be stable. "In sperm whales which we study, we can record a group of sperm whales now, we can record them ten years from now, and we won't notice any difference in the sounds they're making."

BAE Systems hopes to eventually make this technology work with other wavelengths to achieve true invisibility

Militaries from around the world are constantly looking to adopt new technologies that can aid in the protection of soldiers while still carrying out specific duties. For instance, the U.S. military mentioned earlier this year that it wants to test new gadgets every six months in order to put new "capabilities" into the hands of soldiers. Now, there's a new defense technology that could give tanks nighttime invisibility.

The new creation, known as Adaptiv technology, is a camouflage cloak that masks the vehicle's infrared signature by imitating the temperature of its surroundings.

BAE Systems, a British multinational defense, security and aerospace company in London, United Kingdom, is the creator of the camouflage cloak. Using hexagonal panels, or pixels, which are made of a material that can change temperature rapidly, BAE Systems was able to make a cloak that not only allows tanks to mimic its surrounding temperatures, but also makes the tanks look like other objects.

John Fleming of SilverEagles Energy and Tim Maxwell from Texas Tech University, say they have developed a way to make ammonia that is cheap enough so that it could be used as fuel for cars. If their claims turn out to be true, many consumers might consider switching over because ammonia, when burned in an engine, emits nothing but nitrogen and water vapor out the tailpipe. And if that's not enough incentive, they claim they can make the ammonia for just 20 cents a liter (approximately 75 cents a gallon).

The secret to their low cost estimates actually lie in their newly developed method for making hydrogen, which they use to make their ammonia. They say that by using a new kind of transformer that Fleming built, they can reduce the number of cells necessary for electrolysis to such a degree that they can produce hydrogen at almost half the cost of traditional electrolysis methods.

To make the ammonia, the hydrogen produced is pumped into a compression chamber where a piston squeezes it, causing it to heat up; in this case to 400C°. The result is then allowed to escape into another compartment where a reaction is set off by an iron oxide catalyst. This makes the hydrogen grow even hotter to the point where it begins creating ammonia. The ammonia and leftover hydrogen is then allowed to cool down and decompress in yet a third compartment, and in so doing causes another piston to move back and forth creating energy that is fed back into the system to help lower electric consumption. Then, the ammonia is chilled to -75C° and pumped into a tank for use.

Cars already on the road can use ammonia as an additive without modification (up to 10%) and flex cars could be, according to Fleming, easily modified to use ammonia in conjunction with ethanol, allowing for a mixture of 85% ammonia.

New findings from an analysis of 30,000-year-old bacteria show that antibiotic resistance is nothing new, rather a widespread natural phenomenon that somehow preceded the breakthroughs of modern medicine.

The DNA of the old bacteria was recovered from permafrost soil in Canada's Yukon Territory.

The results are published in a recent issue of Nature.

Experts now say the new finding highlights the need to sparingly use antibiotics, seeing that the genes for its resistance are widespread and can easily be promoted by antibiotics.

"Antibiotic resistance is seen as a current problem and the fact that antibiotics are becoming less effective because of resistance spreading in hospitals is a known fact," said Gerry Wright, scientific director of the Michael G. DeGroote Institute for Infectious Disease Research and Hendrik Poinar. "The big question is where does all of this resistance come from?"

Pixellated thermal armour cloak conceals or disguises

Engineers in Sweden have announced the development of a prototype tank which is covered in "pixels" that enable it to disappear from thermal images - or to disguise itself as something else.

The "Adaptiv" system, funded by the Swedish Defence Materiel Administration (FMV), covers the test vehicle in hexagonal panels whose temperature can be quickly adjusted. The vehicle's own thermal cameras scan the background against which the tank is seen from each aspect, and the system can then adjust the pixels to match, making it very hard to see using thermal imaging systems. Alternatively, the pixels can be manipulated to present the appearance of something other than a tank - for instance a car or truck.

Researchers have created the smallest electric motor ever devised.

The motor, made from a single molecule just a billionth of a metre across, is reported in Nature Nanotechnology.

The minuscule motor could have applications in both nanotechnology and in medicine, where tiny amounts of work can be put to efficient use.

Tiny rotors based on single molecules have been shown before, but this is the first that can be individually driven by an electric current.

According to a new study, the month in which your child is born may determine what career he or she is likely to follow as an adult.

The study, conducted by the UK Office for National Statistics (ONS), found that being born in a certain month indicates a statistical likelihood of what job a person will end up with. Researchers in the study also found that the month in which babies are born could also affect everything from intelligence to how long they live.

Using information from the last national census, the ONS analyzed the birth months of people from 19 different careers, reports the Daily Mail.

They found that general practitioners and debt collectors have the greatest percentage of January births, while sheet-metal workers have the lowest percentage. February newcomers appear to have a greater chance of becoming artists, and March is a good month for pilots, according to the ONS study.

The team said their findings suggest that both April and May have a fairly even spread of career paths. They said that babies born during the summer months (June, July and August) have a much lower chance of having high-end, top-paying careers, such as doctor, dentist, or professional athlete.

This image reveals the dark sediments and worn path of what was once a river delta, connecting a river with its lake terminus. Though this river bed has been dry for eons, it's proof that rivers once ran on Mars.

Proof of rivers and lakes like this are not unheard of on Mars, but this finding by the ESA's Mars Express orbiter is still a rare and impressive find. It's located in the planet's Southern Highlands, specifically in the Eberswalde crater. The river delta is quite small by Earth standards - it's got nothing on the famous Nile, Amazon, and Mississippi deltas, but then, few rivers do - but its location is rather more important than its size. It's some of the clearest proof that liquid water did indeed flow on the surface of Mars in not insignificant quantities, albeit eons ago.