It’s Official: Water Found On the Moon

This mosaic, taken from a NASA animation, shows altitude measurements of the moon's south pole from the LOLA instrument aboard the Lunar Reconnaissance Orbiter. Some craters, including Cabeus A that will be hit by the LCROSS probe, are named in this view released Sept. 17, 2009. Credit: NASA/GSFC

Source: Space.com

Since man first touched the moon and brought pieces of it back to Earth, scientists have thought that the lunar surface was bone dry. But new observations from three different spacecraft have put this notion to rest with what has been called “unambiguous evidence” of water across the surface of the moon.

The new findings, detailed in the Sept. 25 issue of the journal Science, come in the wake of further evidence of lunar polar water ice by NASA’s Lunar Reconnaissance Orbiter and just weeks before the planned lunar impact of NASA’s LCROSS satellite, which will hit one of the permanently shadowed craters at the moon’s south pole in hope of churning up evidence of water ice deposits in the debris field.

The moon remains drier than any desert on Earth, but the water is said to exist on the moon in very small quantities. One ton of the top layer of the lunar surface would hold about 32 ounces of water, researchers said.

“If the water molecules are as mobile as we think they are — even a fraction of them — they provide a mechanism for getting water to those permanently shadowed craters,” said planetary geologist Carle Pieters of Brown University in Rhode Island, who led one of the three studies in Science on the lunar find, in a statement. “This opens a whole new avenue [of lunar research], but we have to understand the physics of it to utilize it.”

Finding water on the moon would be a boon to possible future lunar bases, acting as a potential source of drinking water and fuel.

Apollo turns up dry

When Apollo astronauts returned from the moon 40 years ago, they brought back several samples of lunar rocks.

The moon rocks were analyzed for signs of water bound to minerals present in the rocks; while trace amounts of water were detected, these were assumed to be contamination from Earth, because the containers the rocks came back in had leaked.

“The isotopes of oxygen that exist on the moon are the same as those that exist on Earth, so it was difficult if not impossible to tell the difference between water from the moon and water from Earth,” said Larry Taylor of the University of Tennessee, Knoxville, who is a member of one of the NASA-built instrument teams for India’s Chandrayaan-1 satellite and has studied the moon since the Apollo missions.

While scientists continued to suspect that water ice deposits could be found in the coldest spots of south pole craters that never saw sunlight, the consensus became that the rest of the moon was bone dry.

But new observations of the lunar surface made with Chandrayaan-1, NASA’s Cassini spacecraft, and NASA’s Deep Impact probe, are calling that consensus into question, with multiple detections of the spectral signal of either water or the hydroxyl group (an oxygen and hydrogen chemically bonded).

Three spacecraft

Chandrayaan-1, India’s first-ever moon probe, was aimed at mapping the lunar surface and determining its mineral composition (the orbiter’s mission ended 14 months prematurely in August after an abrupt malfunction). While the probe was still active, its NASA-built Moon Mineralogy Mapper (M3) detected wavelengths of light reflected off the surface that indicated the chemical bond between hydrogen and oxygen — the telltale sign of either water or hydroxyl.

Because M3 can only penetrate the top few millimeters of lunar regolith, the newly observed water seems to be at or near the lunar surface. M3′s observations also showed that the water signal got stronger toward the polar regions. Pieters is the lead investigator for the M3 instrument on Chandrayaan-1.

Cassini, which passed by the moon in 1999 on its way to Saturn, provides confirmation of this signal with its own slightly stronger detection of the water/hydroxyl signal. The water would have to be absorbed or trapped in the glass and minerals at the lunar surface, wrote Roger Clark of the U.S. Geological Survey in the study detailing Cassini’s findings.

The Cassini data shows a global distribution of the water signal, though it also appears stronger near the poles (and low in the lunar maria).

Finally, the Deep Impact spacecraft, as part of its extended EPOXI mission and at the request of the M3 team, made infrared detections of water and hydroxyl as part of a calibration exercise during several close approaches of the Earth-Moon system en route to its planned flyby of comet 103P/Hartley 2 in November 2010.

Deep Impact detected the signal at all latitudes above 10 degrees N, though once again, the poles showed the strongest signals. With its multiple passes, Deep Impact was able to observe the same regions at different times of the lunar day. At noon, when the sun’s rays were strongest, the water feature was lowest, while in the morning, the feature was stronger.

“The Deep Impact observations of the Moon not only unequivocally confirm the presence of [water/hydroxyl] on the lunar surface, but also reveal that the entire lunar surface is hydrated during at least some portion of the lunar day,” the authors wrote in their study.

The findings of all three spacecraft “provide unambiguous evidence for the presence of hydroxyl or water,” said Paul Lucey of the University of Hawaii in an opinion essay accompanying the three studies. Lucey was not involved in any of the missions.

The new data “prompt a critical reexamination of the notion that the moon is dry. It is not,” Lucey wrote.

This Mini-RF image from NASA's powerful Lunar Reconnaissance Orbiter shows radar imagery of the lunar south pole, a potential reservoir for hidden water ice, in new images released Sept. 17, 2009. Credit: NASA/APL/LPI

Where the water comes from

Combined, the findings show that not only is the moon hydrated, the process that makes it so is a dynamic one that is driven by the daily changes in solar radiation hitting any given spot on the surface.

The sun might also have something to do with how the water got there.

There are potentially two types of water on the moon: that brought from outside sources, such as water-bearing comets striking the surface, or that that originates on the moon.

This second, endogenic, source is thought to possibly come from the interaction of the solar wind with moon rocks and soils.

The rocks and regolith that make up the lunar surface are about 45 percent oxygen (combined with other elements as mostly silicate minerals). The solar wind — the constant stream of charged particles emitted by the sun — are mostly protons, or positively charged hydrogen atoms.

If the charged hydrogens, which are traveling at one-third the speed of light, hit the lunar surface with enough force, they break apart oxygen bonds in soil materials, Taylor, the M3 team member suspects. Where free oxygen and hydrogen exist, there is a high chance that trace amounts of water will form.

The various study researchers also suggest that the daily dehydration and rehydration of the trace water across the surface could lead to the migration of hydroxyl and hydrogen towards the poles where it can accumulate in the cold traps of the permanently shadowed regions.

“Bigwig” ushered “nonsense” paper into top journal, say scientists

An article claiming caterpillars and butterflies evolved separately has attracted widespread criticism, writes Zoë Corbyn

Butterfly experts have been angered by the appearance in a top journal of a paper they say is bizarre and unsupported by evidence, claiming it was published only because it was ushered in by a “bigwig” in the field.

The paper, by Donald Williamson, a retired academic from the University of Liverpool, was published in advance online late last month in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Its publication was via a special “communication” mechanism understood to be unique to PNAS. This allows national academy members to bypass normal editorial procedures and submit papers that they consider to be of particular importance without the normal peer-review requirements, although they must obtain two referees.

Dr Williamson’s article was communicated by Lynn Margulis, a well-known professor in the department of geosciences at the University of Massachusetts Amherst.

It makes the extraordinary claim that caterpillars and butterflies have different evolutionary histories – that rather than being a single lineage that evolved through two different life stages, they are a hybrid that resulted from the accidental mating of a flying insect with a worm-like species.

But butterfly experts say the idea is unsubstantiated and have called into question the method by which such a seemingly unsupportable theory could end up in one of the world’s most prestigious journals.

In a posting called “Worst paper of the year?” on his blog “Why Evolution Is True”, Jerry Coyne, a professor of biology at the University of Chicago, says the paper’s appearance is an example of a “bigwig” exercising undue influence.

Max Telford, a reader in zoology at University College London, told Times Higher Education that “clearly something has gone wrong”.

“There is no science in it. I don’t think it could possibly have got through on a normal peer-review process,” he said. “It is unique to PNAS that they have got this back-door way of getting things through.”

He added that Professor Margulis was an “incredibly important and highly respected” scientist in evolutionary circles, having come up with the idea, considered dubious at the time but now textbook science, that cell organelles originated as bacteria that were subsequently absorbed by the cell. But extrapolating that thinking to butterflies went too far, he said.

“Maybe there needs to be a forum for off-the-wall ideas, but at the same time, this was not reviewed to the standard that one would expect in PNAS,” he said.

Chris Jiggins, who leads the Butterfly Genetics Group at the University of Cambridge, also rubbished the paper and labelled the PNAS system “quite nepotistic”.

“I think it’s nonsense – there is no data in the paper. It claims to use molecular biology evidence in the abstract, but there isn’t actually anything in there,” he said.

Professor Margulis did not respond to a request from Times Higher Education to comment.

Dr Williamson described Professor Margulis as a “good friend” who had been an “enthusiastic supporter” of his hypothesis over the years.

Saying that he had been studying larvae “considerably longer” than any of his detractors, he challenged the sceptics to refute the hypothesis by DNA analysis. He did note, however, that the paper in question, “Caterpillars evolved from onychophorans by hybridogenesis”, had been rejected by seven journals before being published in PNAS.

Meanwhile, in a September editorial, PNAS announced plans to scrap the communication submission process from June next year.

Source: Times Higher Education, Zoë Corbyn, 13th Sept

‘Lost’ Seabird Seen Once More

Up to eight Fiji petrels were seen over an 11-day period

One of the world’s rarest and most elusive birds has finally been seen flying in its natural habitat.

The Fiji petrel, a seabird that once “went missing” for 130 years, has been sighted flying at sea, near the island of Gua in the Pacific Ocean.

The culmination of a meticulously planned bird hunt, Birdlife International researchers sighted the birds 25 nautical miles south of Gua.

Up to eight individuals were seen and photographed over 11 days.

The 30cm tall dark-brown Fiji petrel (Pseudobulweria macgillivrayi) is one of the most elusive of all birds.

Originally, the species was known from just a single immature specimen, collected in 1855 on Gau Island, Fiji.

But then the bird “went missing” with no further confirmed sightings of it for almost 130 years.

Then in 1984, an adult was caught and photographed on Gua, then released.

Since then, there have been a handful of reports of “grounded” birds that had crashed onto village roofs on the island. Most were immature birds, of which a few died.

Due to the extremely limited number of sightings, the bird is also inferred to be one of the rarest of all bird species.

It is one of 192 bird species which are list as Critically Endangered by the International Union for the Conservation of Nature.

Stinky lure

But while there have been ten unconfirmed reports of the bird at sea, with the latest a possible Fiji Petrel sighted around 400km north of Bougainville Island, until now there has been no confirmed sightings.

That was until in May, when scientists and volunteers working with Birdlife International and

NatureFiji-MareqetiViti, a partner conservation organisation based in Fiji, set out to find the bird in its natural habitat.

The search for the elusive petrel is described in a paper in the latest Bulletin of the British Ornithologists’ Club.

The researchers lured the bird with a specially made food, made from finely cut fish offal mixed with very dense fish oil.

These were then frozen into 10kg blocks, which persist for over an hour in the water, creating a pungent oil slick which attracts petrels from some miles away.

On the second day of the expedition, the first Fiji Petrel appeared, approaching the chum slick from downwind, slowly zigzagging over the slick, and suddenly changing direction to drop onto a floating morsel.

In all, the expedition team believe they saw eight individuals over eleven days of observations.

“Finding this bird and capturing such images was a fantastic and exhilarating experience,” says ornithologist Hadoram Shirihai, who lead the search team.

In 2008, Mr Shirihai also rediscovered the Critically Endangered Beck’s Petrel (Pseudobulweria becki) a bird that was also only known from two sightings in the Pacific made in the 1920s.

“To see such a little-known bird at such close range was magical,” added fellow expedition member Mr Tony Pym, describing his joy at seeing the Fiji petrel flying over the waves.

More surveys in 2010 are now planned to to locate the breeding area of the Fiji Petrel, says Dick Watling of NatureFiji-MareqetiViti.

“Once we know the location, we can assess what needs to be done to turn around the fortunes of this species,” he says.

Source: BBC Online, Matt Walker

Antibiotic Resistance Clue Discovered

MRSA (Methicillin-Resistant Stapylococcus aureas) "Here we have a short-cut, where we don't have to invent new antibiotics" Dr Evgeny Nudler, Study leader

Source: BBC Online, Photo credit: Wikipedia, CDC/ Janice Carr/ Deepak Mandhalapu, M.H.S

US scientists have uncovered a defence mechanism in bacteria that allows them to fend off the threat of antibiotics.

It is hoped the findings could help researchers boost the effectiveness of existing treatments.

The study published in Science found that nitric oxide produced by the bacteria eliminates some key effects of a wide range of antibiotics.

One UK expert said inhibiting nitric oxide synthesis could be an important advance for tackling tricky infections.

Antibiotic resistance, for example with MRSA, is a growing problem and experts have long warned of the need to develop new treatments.

The latest research, done by a team at New York University, showed that in bacteria the production of nitric oxide – a small molecule made up of one nitrogen and one oxygen atom – increased their resistance to antibiotics.

They found the enzymes responsible for producing nitric oxide were activated specifically in response to the presence of the antibiotics.

They also showed that nitric oxide alleviates damage caused by the drugs as well as helping to neutralise many of the toxic compounds within the antibiotic.

The researchers then showed that eliminating nitric oxide production in the bacteria allowed the antibiotics to work at lower, less toxic doses.

More effective

Study leader, Dr Evgeny Nudler, said developing new medicines to fight antibiotic resistance, such as that seen with MRSA is a “huge hurdle”.

“Here, we have a short cut, where we don’t have to invent new antibiotics.

“Instead we can enhance the activity of well-established ones, making them more effective at lower doses.

Dr Matthew Dryden, consultant in microbiology and communicable disease at Royal Hampshire County Hospital and general secretary of the British Society for Antimicrobial Chemotherapy, said if the enzyme which creates nitric oxide could be inhibited, it could suppress the ability of the bacteria to counteract antibiotics.

“This would be a useful therapeutic advance, especially as we are running out of new classes of antibiotics and there is less antibiotic development in general.”

———————————————–

What I do not understand is that nitric oxide itself is integral in many essential bodily functions, such as vasodilation, neurotransmission as well as being employed by the immune system to kill infecting bacteria.

Any drug or method that decreases nitric oxide synthesis in drug-resistant bacteria must hence be extremely specific to their nitric oxide synthetase enzymes.

Does anybody else know something I don’t about the particular research above? Or understand the process of drug resistance via nitric oxide better than what I can extract from that article?

Turtle Thought to be Extinct Spotted in Myanmar

The rare Arakan forest turtle, once though to be extinct, has been rediscovered in a remote forest in Myanmar, boosting chances of saving the reptile after hunting almost destroyed its population, researchers said Monday.

Texas researcher Steven Platt and staff from the New York-based Wildlife Conservation Society discovered five of the brown-and-tan-spotted turtles in May during a survey of wildlife in the Rakhine Yoma Elephant Sanctuary.

The sanctuary contains thick stands of impenetrable bamboo forests, with the only trails made by the park’s elephants, said Platt, of Sul Ross State University in Alpine, Texas.

Plat said he and his team were able to reach the area only by small boat and endured round-the-clock torrential rains and bands of leeches before finding their first Arakan turtle on May 31.

“At this moment, all of the physical hardships of the trip were forgotten,” Platt said in an e-mail interview.

Native to the Arakan hills of western Myanmar, the turtles were believed extinct for close to a century until they started turning up in Asian food markets in the mid-1990s.

The local name for the turtle is “Pyant Cheezar,” which translates to “turtle that eats rhinoceros feces.” Sumatran rhinos were once found in the area, but vanished half a century ago due to hunting.

Scientists blame the near-disappearance of the turtle on their popularity in Asia as an ingredient in cooking and medicine. Known by its scientific name, Heosemys depressa, it is listed as critically endangered by the International Union for Conservation of Nature and Natural Resources and has proven difficult to breed in captivity.

The discovery in May makes scientists hopeful that the species can survive.

“Throughout Asia, turtles are being wiped out by poachers for the illegal wildlife trade,” Colin Poole, the Wildlife Conservation Society’s director of Asia programs, said in a statement. “We are delighted and astonished that this extremely rare species is alive and well in Myanmar. Now we must do what we can to protect the remaining population.”

Douglas B. Hendrie, a freshwater turtle expert from Education for Nature-Vietnam who did not take part in the research, said he was not surprised by the discovery because he had heard anecdotes of hunters and guides finding the turtle.

“That said, I think it is good to bring attention to the species,” Hendrie said in an e-mail interview, adding that it is an “an important part of furthering the aims of conservation.”

Platt and the conservation society recommend that guard posts be set up on roads leading in and out of the park to thwart poaching and that additional data be collected on the species to develop a conservation plan for it.

Source: Associated Press, Bangkok

Giant Rat Discovered in Papua New Guinea

A new species of giant rat has been discovered deep in the jungle of Papua New Guinea.

VIDEO: TRAPPING A LIVE SPECIMEN

The rat, which has no fear of humans, measures 82cm long, placing it among the largest species of rat known anywhere in the world.

The creature, which has not yet been formally described, was discovered by an expedition team filming the BBC programme Lost Land of the Volcano.

It is one of a number of exotic animals found by the expedition team.

Like the other exotic species, the rat is believed to live within the Mount Bosavi crater, and nowhere else.

“This is one of the world’s largest rats. It is a true rat, the same kind you find in the city sewers,” says Dr Kristofer Helgen, a mammalogist based at the Smithsonian National Museum of Natural History who accompanied the BBC expedition team.

Initially, the giant rat was first captured on film by an infrared camera trap, which BBC wildlife cameraman Gordon Buchanan set up in the forest on the slopes of the volcano.

The expedition team from the BBC Natural History Unit recorded the rat rummaging around on the forest floor, and were awed by its size.

Immediately, they suspected it could be a species never before recorded by science, but they needed to see a live animal to be sure.

Then trackers accompanying the team managed to trap a live specimen.

“I had a cat and it was about the same size as this rat,” says Buchanan.

The trapped rat measured 82cm in length from its nose to its tail, and weighed approximately 1.5kg.

It had a silver-brown coat of thick long fur, which the scientists who examined it believe may help it survive the wet and cold conditions that can occur within the high volcano crater. The location where the rat was discovered lies at an elevation of over 1,000m.

Initial investigations suggest the rat belongs to the genus Mallomys, which contains a handful of other out-sized species.

It has provisionally been called the Bosavi woolly rat, while its scientific name has yet to be agreed.

Other rodents, the group of animals that includes rats, grow to a bigger size.

For example, the largest rodent of all is the capybara, which lives in or near freshwater in South America.

It can grow up to 130cm long and weigh up to 65kg.

The Philippines is also home to a few species of cloud rat which can reach over 2kg in weight.

But of the true rats, which includes urban brown and black rats that belong to the genusRattus, few can match the new species.

In 2007, an expedition to New Guinea led by Conservation International discovered another closely related giant woolly rat, which can weigh up to 1.4kg. It also belongs within the genusMallomys.

However, that species lives in the Foja Mountains, part of the Mamberamo Basin.

Mount Bosavi, where the new rat was found, is an extinct volcano that lies deep in the remote Southern Highlands of Papua New Guinea.

VIDEO: INITIAL SIGHTING VIA INFRARED CAMERA TRAP

The expedition team entered the crater to explore pristine forest, where few humans have set foot.

Even members of the Kasua tribe, who acted as trackers for the expedition, live outside the crater, which is 4km wide and has walls up to 1km high, trapping the creatures that live within.

The island which includes Papua New Guinea and New Guinea is famous for the number and diversity of the rats and mice that live there.

Over 57 species of true “Murid” rats and mice can be found on the island. The larger rats are often caught by hunters and eaten.

Broadcast of The Lost Land of the Volcano series will begin on BBC One on Tuesday 8 September at 2100 BST. The discovery of the Bosavi woolly rat is broadcast as part of the series on BBC One on Tuesday 22 September.

Source: BBC Online, Matt Walker

The Fish with a Transparent Head

If you had asked me 5 minutes ago if I knew of a fish with a transparent dome for a head, I would have to say no.

Strange Jellies of the Icy Depths

Scientists have published descriptions of a range of jelly-like animals encountered during submersible dives into the deep oceans of the Arctic. This deep red Crossota norvegica was observed as deep as 2,600m

Source: BBC Online, Matt Walker / Photos all courtesy of Dr. Kevin Raskoff himself

New details are emerging about the life-forms that survive in one of the world’s most inaccessible places.

Scientists have published descriptions of a range of jelly-like animals that inhabit the deep oceans of the Arctic.

The animals were originally filmed and photographed during a series of submersible dives in 2005.

One of the biggest surprises is that one of the most common animals in the Arctic deep sea is a type of jellyfish that is completely new to science.

The deep Arctic ocean is isolated from much of the water elsewhere on the globe.

One area, known as the Canadian Basin, is particularly cut off by deep-sea ridges. These huge barriers can isolate any species there from other deep-water animals.

So in 2005, an international team of scientists, funded primarily by the US National Oceanic and Atmospheric Administration’s Office of Ocean Exploration and Research, conducted a series of deep-sea dives using a remote operated vehicle (ROV).

Details of what they found have now been published in the journal Deep Sea Research Part II.

“There were a lot of surprises,” says biologist Dr Kevin Raskoff of Monterey Peninsula College in California, US, a leading member of the dive team.

“One thing was just how many different jellies there were, and the sizes of their populations.”

- Dr Kevin Raskoff, Monterey Peninsula College, California

“Some were somewhat well known from other oceans, but had not previously been found in the Arctic. That caused us to rethink our ideas about what the typical habitat would be for the species. We also discovered a number of new species that had not been found before.”

During a series of dives to depths of 3000m, the ROV filmed over 50 different types of gelatinous or jelly-like animal.

A jellyfish new to science, which will be formally described later this year. The small blue jelly, a type of Narcomedusae, lives in a narrow depth range of 1,400 - 2,000m

The majority of animals recorded were Medusae, a particular type of jellyfish that tend to be bell or disc shaped.

Other jelly-like creatures seen included ctenophores, an unusual group that can look like jellyfish, but are not able to sting, siphonophores, which are actually colonies of smaller animals living together in a structure that looks like a single, larger animal, and larvaceans, plankton-like creatures unrelated to jellyfish.

Of all the Medusae observed, two species dominated at most locations visited by the ROV.

The first was a species called Sminthea arctica, which lived at depths ranging from 100m to 2,100m. This jellyfish has been recorded before by scientific expeditions.

However, the other common jelly was a species new to science.

“Probably the single most interesting discovery was a new species of a small blue jellyfish, from a group called the Narcomedusae,” says Dr Raskoff.

“This group has several interesting features that set them apart from typical jellyfish, such as the fact that they hold their tentacles over their bell as they swim.”

Most jellyfish let their tentacles drift in the water behind them, but the new species holds its tentacles out in front, perhaps enabling it to better catch prey.

The new species is so unusual that it has been classified within its own genus, and will be formally described later this year.

“It was also the third most common jellyfish found on the cruise, which is really surprising when you think about the fact that even the most common species in the area can be totally new and unexpected species,” says Dr Raskoff.

Another striking find was a type of ctenophore called Aulacoctena, which is one of the most spectacular examples of its kind.

A large bright orange Aulacoctena species, about 15 cm long, was observed on 6 occasions. The striking orange colouration appears to come from their diet of bright orange worms

At over 15cm long, its tentacles can grip almost anything underwater, yet little is known about its lifestyle.

However, one of the specimens collected by the ROV ejected its stomach contents, which revealed it may had fed on a bright orange animal.

The researchers suspect it feeds on bright orange worms that also live in the Arctic deep, and it gets it colour from its prey.

The scientists are now keen to find out much more about how these strange and enigmatic creatures interact with their environment, and how they influence or underpin the ecology of the deep ocean in which they live.

They also hope to raise funds to explore other little-visited regions of the deep Arctic ocean, as well as exploring the Aleutian trench off the coast of Alaska.

“You don’t have to go too far to find interesting areas to study, you just have to dive deep,” says Dr Raskoff.

Chrysaora melanaster is one of the largest Arctic jellies, living in the top layer of water at depths of between 20m and 40m, where the temperature remains nearly constant

This red-lipped cydippid ctenophore was a common deep-water species between 1,300 to 2,400m. It still awaits description

Crossota millsae is also found off California and Hawaii. This specimen was collected near the bottom of the Arctic Ocean at 2,000m

Benthocodon hyalinus is a small jellyfish previously known from Antarctica and perhaps California

The large colonial physonect siphonophore Marrus orthocanna. When stretched out, this animal would be over 3m long

The "sea angel" Clione limacina is a naked pteropod, a shell-less snail, and was found in the surface waters, down to 350m. This species also lives in the Antarctic Ocean.

Pigeons’ Wings Sound the Alarm

Photo Credit: Lip Kee on Flickr

Startled pigeons might not appear to epitomise the wonder of evolution, but a study has discovered that the birds can communicate with their wings.

When a crested pigeon (Ocyphaps lophotes) is startled into flight its wings produce a whistling sound which serves as an alarm call.

The pigeons have “modified wings” that produce the whistle as they fly, but only this sudden take-off creates the alarm that causes other birds to flee.

The team report their findings in the Royal Society journal Proceedings B.

Robert Magrath at the Australian National University (ANU) in Canberra led the study.

He and his colleague Mae Hingee took sound recordings from the birds.

“We audio recorded the sound of birds flying off from a feeder in routine flight and compared those sounds to those produced when we scared pigeons into take-off with a gliding model hawk,” explained Dr Magrath.

The birds that took off in alarm produced louder whistles with a more rapid tempo of “notes”, he told BBC News.

The researchers played back both alarmed and routine whistles to flocks of feeding pigeons.

“We found that they only fled to cover after hearing the alarmed whistles. [They] could tell the difference, and acted appropriately in response,” said Dr Magrath.

He described how the birds’ “modified” wings create the sound.

“The birds have one very narrow primary flight feather (primaries), which we suspect vibrates during flapping flight to produce the whistling,” he said.

Sue Anne Zollinger, an animal communication researcher from the University of St Andrews who was not involved in the study, said the “playback” element of the study was revealing.

“Lots of people have studied sound production by birds’ wings, but here the researchers have actually been able to put it into a context, [and] shown that the sound has a communication role,” Dr Zollinger told BBC News.

She added that this information would help researchers to understand why being in a flock might be useful for some birds.

The ANU researchers pointed out that while scientists understand some evolutionary advantages of a flock, such as having more pairs of eyes to spot predators, this has clarified exactly how the birds understand that one of their flock has spotted a potential threat.

Dr Magrath concluded: “We’d like to find out more about the mechanism of sound production, try to work out whether it evolved specifically as an alarm signal, and see if other birds also use wing sounds [as alarm calls].”

Source: BBC Online, Photos sourced by me. Due credit given.

Scientists: We’re All Mutants

Each of us has at least 100 new mutations in our DNA, according to research published in the journal Current Biology.

Scientists have been trying to get an accurate estimate of the mutation rate for over 70 years.

However, only now has it been possible to get a reliable estimate, thanks to “next generation” technology for genetic sequencing.

The findings may lead to new treatments and insights into our evolution.

J.B.S Haldane

In 1935, one of the founders of modern genetics, JBS Haldane, studied a group of men with the blood disease haemophilia. He speculated that there would be about 150 new mutations in each of us.

Others have since looked at DNA in chimpanzees to try to produce general estimates for humans.

However, next generation sequencing technology has enabled the scientists to produce a far more direct and reliable estimate.

They looked at thousands of genes in the Y chromosomes of two Chinese men. They knew the men were distantly related, having shared a common ancestor who was born in 1805.

By looking at the number of differences between the two men, and the size of the human genome, they were able to come up with an estimate of between 100 and 200 new mutations per person.

Impressively, it seems that Haldane was right all along.

Unimaginable

Deoxyribonucleic Acid (DNA)

One of the scientists, Dr Yali Xue from the Wellcome Trust Sanger Institute in Cambridgeshire, said: “The amount of data we generated would have been unimaginable just a few years ago.

“And finding this tiny number of mutations was more difficult than finding an ant’s egg in an emperor’s rice store.”

New mutations can occasionally lead to severe diseases like cancer. It is hoped that the findings may lead to new ways to reduce mutations and provide insights into human evolution.

Joseph Nadeau, from the Case Western Reserve University in the US, who was not involved in this study said: “New mutations are the source of inherited variation, some of which can lead to disease and dysfunction, and some of which determine the nature and pace of evolutionary change.

“These are exciting times,” he added.

“We are finally obtaining good reliable estimates of genetic features that are urgently needed to understand who we are genetically.”

Source: BBC Science