Starling murmurations, new research


This video is about a starling murmuration in Britain.

From Science:

How bird flocks are like liquid helium

By Marcus Woo

27 July 2014 1:00 pm

A flock of starlings flies as one, a spectacular display in which each bird flits about as if in a well-choreographed dance. Everyone seems to know exactly when and where to turn. Now, for the first time, researchers have measured how that knowledge moves through the flock—a behavior that mirrors certain quantum phenomena of liquid helium.

“This is one of the first studies that gets to the details of how groups move in unison,” says David Sumpter of Uppsala University in Sweden, who was not part of the study.

The remarkable accord with which starling flocks fly has long puzzled researchers and bird watchers alike. In the 1930s, the ornithologist Edmund Selous even suggested that the birds cooperate via telepathy. Researchers have since turned to more scientifically sound ideas, using mathematical models.

In the 1990s, physicist Tamás Vicsek of Eötvös Loránd University in Budapest came up with one of the more successful models, which is based on the principle that each bird flies in the same direction as its neighbors. If a bird angles right, the ones next to it will turn to stay aligned. Although this model reproduces many features well—how a flock swiftly aligns itself from a random arrangement, for example—a team of researchers from Italy and Argentina has now discovered that it doesn’t accurately describe in detail how flocks turn.

In their new study, the team, led by physicists Andrea Cavagna and Asja Jelic of the Institute for Complex Systems in Rome, used high-speed cameras to film starlings—which are common in Rome and form spectacular flocks—flying near a local train station. Using tracking software on the recorded video, the team could pinpoint when and where individuals decide to turn, information that enabled them to follow how the decision sweeps through the flock. The tracking data showed that the message to turn started from a handful of birds and swept through the flock at a constant speed between 20 and 40 meters per second. That means that for a group of 400 birds, it takes just a little more than a half-second for the whole flock to turn.

“It’s a real tour de force of measurement,” says Sriram Ramaswamy of the Tata Institute of Fundamental Research’s Centre for Interdisciplinary Sciences in Hyderabad, India, who wasn’t part of the research.

The fact that the information telling each bird to turn moves at a constant speed contradicts the Vicsek model, Cavagna says. That model predicts that the information dissipates, he explains. If it were correct, not all the birds would get the message to turn in time, and the flock wouldn’t be able to fly as one.

The team proposes that instead of copying the direction in which a neighbor flies, a bird copies how sharply a neighbor turns. The researchers derived a mathematical description of how a turn moves through the flock. They assumed each bird had a property called spin, similar to the spins of elementary particles in physics. By matching one another’s spin, the birds conserved the total spin of the flock. As a result of that conservation, the equations showed that the information telling birds to change direction travels through the flock at a constant speed—exactly as the researchers observed. It’s this constant speed that enables everyone to turn in near-unison, the team reports online today in Nature Physics.

The new model also predicts that information travels faster if the flock is well aligned—something else the team observed, Cavagna says. Other models don’t predict or explain that relationship. “This could be the evolutionary drive to have an ordered flock,” he says, because the birds would be able to maneuver more rapidly and elude potential predators, among other things.

Interestingly, Cavagna adds, the new model is mathematically identical to the equations that describe superfluid helium. When helium is cooled close to absolute zero, it becomes a liquid with no viscosity at all, as dictated by the laws of quantum physics. Every atom in the superfluid is in the same quantum state, exhibiting a cohesion that’s mathematically similar to a starling flock.

The similarities are an example of how deep principles in physics and math apply to many physical systems, Cavagna says. Indeed, the theory could apply to other types of group behavior, such as fish schools or assemblages of moving cells, Sumpter says.

Other models, such as the Vicsek model or others that treat the flock as a sort of fluid, probably still describe flock behavior over longer time and length scales, Ramaswamy says. But it’s notable that the new model, which is still based on relatively simple principles, can accurately reproduce behavior at shorter scales. “I think that’s cool,” he says. “That’s an achievement, really.”

Sumpter agrees. “It’s kind of reassuring we don’t need to think about the telepathic explanation,” he says.

See also here.

Women in British science, new research


This video from Ireland says about itself:

Reflections on women in science; diversity and discomfort: Jocelyn Bell Burnell at TEDxStormont

Apr 4, 2013

Dame Jocelyn Bell Burnell inadvertently discovered pulsars as a graduate student in radio astronomy in Cambridge, opening up a new branch of astrophysics — work recognised by the award of a Nobel Prize to her supervisor. She is now a Visiting Professor in Oxford.

From Kingston University in London, England:

Unearthing the hidden women of science and inspiring the next generation

08 May 2013

A group of historians and scientists is about to embark on a major project to scrutinise the role of British women in science. It will focus on finding and assessing the careers of scientific women who may not have received credit or recognition for their work. The £33k project, funded by the Arts and Humanities Research Council and run jointly by Kingston University, University of Liverpool, the Royal Society and the Rothschild Archive London, aims to examine how women were involved in scientific societies between the years 1830 to 2012 and look at how that can inform policy today.

It will involve the establishment of a network of academics to gain a better understanding of how historical perspectives might impact future education policy making. Recent statistics show that only a third of science, technology, engineering and maths students in Britain are female and just 11 per cent of senior positions in science are held by women.

“Women’s unequal participation in science subjects at all levels, both in education, academia and in industry, is currently receiving close attention from policy makers, educationalists and social commentators,” project leader Dr Susan Hawkins, a senior history lecturer from Kingston University, said. “Part of the purpose of our work will be to closely examine data on women in science in the 19th and 20th Centuries. The hope is that by looking at women’s relationship with science in the past, we can pinpoint ways to encourage young women to participate more fully in the subject.”

There was a wealth of historical information which could open a window into the past but it was often dispersed across different archives, Dr Hawkins, who originally trained as a scientist, explained. “Through the network we hope to identify where these archives are and what revelatory material they may contain.” Part of the project will involve a shadowing scheme which will allow researchers studying the history of science to spend time alongside a female scientist in the laboratory, gaining an understanding of how science works today and the challenges faced by women in the field.

The network will be organised around a series of events, including three workshops, a two-day international conference to be held at the Royal Society in May 2014 and an exhibition open to the public. The first workshop will aim to identify archives that may contain information on women in science. It will concentrate on two groups of women – those whose work was recognised by the scientific community of their time and those who, despite producing work of high standard, were not. “The intention is to look at the characteristics that link the two groups of women and also to find out what set them apart,” Dr Hawkins added. Another workshop will focus on identifying possible oral history projects.

“The final workshop will pull together the findings from the first two events and allow us to make recommendations to government on future projects to help increase female participation in science,” Dr Hawkins said.

The issue of the representation of women in science has dominated headlines in the media in recent months. According to a report in last month’s Independent newspaper, female professors account for 5.5 per cent in physics, 6 per cent in chemistry and maths and just 2 per cent in engineering. This has prompted growing calls for better representation of women in science both in universities and in industry – a sentiment also echoed by Kingston University’s new Chancellor American playwright and author Bonnie Greer. “It is crucial that women continue to take up the study of science and maths as historically women have been kept out of these professions, so who knows what genius has been lost?” she said recently. “When you think of all the big problems that are out there waiting to be solved, every ounce of human intelligence is needed.”

Things were extremely tough for women in science in the past and they often did not receive proper recognition, according to Dr Hawkins. “It was a real struggle. For instance, the Royal Society didn’t accept female fellows until as late as 1945,” she said. “There were women in the scientific field but they really had to fight to be recognised, independent of any men they might have been working with.”

Guests from around the world will attend a launch event for the project at the International Congress for the History of Science Technology and Medicine to be held in Manchester in July.

WOMEN IN SCIENCE “‘It’s death by a thousand cuts. Every day you’re faced with some comment, some snide remark, some inability to get a name on a research paper. And with an accumulation of those experiences, women tend to walk with their feet.’ That’s Janet Bandows Koster, executive director of the Association for Women in Science explaining one of the reasons why so few women pursue science careers — and why those who do often abandon them.” [HuffPost]

Tasmanian tiger extinction, new research


This video says about itself:

Here is a combination of all the footage of the Tasmanian Tiger, now believed to be extinct.

From Wildlife Extra:

Humans alone responsible for extinction of Tasmanian Tiger

February 2013. Humans alone were responsible for the demise of Australia’s iconic extinct native predator, the Tasmanian Tiger or thylacine, according to a new study led by the University of Adelaide.

Using a new population modelling approach, the study contradicts the widespread belief that disease must have been a factor in the thylacine’s extinction.

Government sponsored hunting

The thylacine was a unique marsupial carnivore found throughout most of Tasmania before European settlement in 1803. Between 1886 and 1909, the Tasmanian government encouraged people to hunt thylacines and paid bounties on over 2000 thylacine carcasses. Only a handful of animals were located after the bounty was lifted and the last known thylacine was captured from the wild in 1933.

“Many people, however, believe that bounty hunting alone could not have driven the thylacine extinct and therefore claim that an unknown disease epidemic must have been responsible,” says the project leader, Research Associate Dr Thomas Prowse, School of Earth and Environmental Sciences and the Environment Institute.

“We tested this claim by developing a ‘metamodel’ – a network of linked species models – that evaluated whether the combined impacts of Europeans could have exterminated the thylacine, without any disease.”

The mathematical models used by conservation biologists to simulate the fate of threatened species under different management strategies (called population viability analysis or PVA) traditionally neglect important interactions between species. The researchers designed a new approach to PVA that included species interactions.

“The new model simulated the directs effects of bounty hunting and habitat loss and, importantly, also considered the indirect effects of a reduction in the thylacine’s prey (kangaroos and wallabies) due to human harvesting and competition from millions of introduced sheep,” Dr Prowse says.

Disease not a factor

“We found we could simulate the thylacine extinction, including the observed rapid population crash after 1905, without the need to invoke a mystery disease. We showed that the negative impacts of European settlement were powerful enough that, even without any disease epidemic, the species couldn’t escape extinction.”

The study ‘No need for disease: testing extinction hypotheses for the thylacine using multi-species metamodels‘, which also involved Professors Corey Bradshaw and Barry Brook from the University of Adelaide’s Environment Institute, Professor Chris Johnson from the University of Tasmania, and Dr Bob Lacy, Chicago Zoological Society, has been published online in the Journal of Animal Ecology.

Is the Tasmanian tiger really extinct? Here.

Anti-nazi computer inventor Turing killed by homophobia


This video from Britain is called A brief video biography of the achievements of Alan Turing.

By Peter Frost in Britain:

Computers that beat the nazis

Thursday 20 December 2012

Bletchley Park, on the edge of what is now Milton Keynes, was the site of Britain’s main decryption establishment in the second world war where nazi codes were broken.

Most important were the ciphers of the German Enigma and Lorenz machines. The high-level intelligence produced at Bletchley Park played a crucial part in the Allied victory.

Bletchley was also the place that saw the conception and birth of the modern computer.

Given that sort of history you would expect any nation in the world to have turned it into a celebration of national pride. It should be a sparkling, well-funded and well-maintained tribute to its unique place in technological history and the victory over fascism.

Not here. Britain ignored the place for years. It was even threatened with demolition and clearance. Only the dedicated work of countless volunteers and enthusiasts have preserved and saved it for future generations to marvel at.

Today it’s a motley, not to mention scruffy, collection of museums and displays run by a diverse collection of enthusiast groups. It is still an amazing place to visit.

Disgracefully it wasn’t until last year that Bletchley Park finally received a Heritage Lottery Fund grant large enough to finally restore the site and tell its story in the way it deserves.

Even then the volunteers had to raise matching funds. By June this year they had successfully raised the money to unlock the grants.

Alan Mathison Turing worked at Bletchley Park. Mathematician, code-breaker and cryptanalyst Turing was the man who invented the computer.

He is widely considered to be the father of computer science and artificial intelligence. He was born a century ago in 1912. He was also gay.

At Bletchley Park he was in charge of Hut 8, the key section responsible for breaking German naval codes.

He devised a number of ways of unlocking German ciphers, including electromechanical machines – early computers – that unlocked the codes generated by the famous Enigma machines.

After the war, in 1952, Turing’s homosexuality resulted in a criminal prosecution. Turing met a 19-year-old called Arnold Murray and invited him to his house. Murray betrayed him.

A friend of Murray burgled Turing’s house, confident that the mathematician, fearful of exposure, would not tell the police.

The two men misjudged Turing. He reported the theft and admitted a sexual relationship with Murray.

To avoid prison, Turing accepted chemical castration with female hormones. The treatment ruined his health and fitness.

Previously he had often run the 40 miles from Bletchley Park to London for meetings. Only an injury had kept him out of the 1948 London Olympic marathon team.

Turing died a broken man in 1954 – he was 41. He bit into an apple dipped in cyanide.

An inquest recorded suicide but his mother believed it was an accident. Some even suspected he may have been murdered.

It took 55 years before British prime minister Gordon Brown, responding to a petition, made an official public apology for the appalling way Turing was treated.

“On behalf of the British government and all those who live freely thanks to Alan’s work, I am very proud to say ‘we’re sorry – you deserved so much better’,” he said.

Brown wrote: “Alan and the many thousands of other gay men who were convicted, as he was, under homophobic laws were treated terribly.”

Shamefully, however, the extraordinary achievements of this British scientific genius have still never been properly recognised and he has yet to be officially pardoned. The present state of Bletchley Park is an outstanding example of this, although Turing does have a statue in Manchester.

Some say Apple computer’s logo – an apple with a bite taken out of it – commemorates Turing’s curious death.

Turing admirer Stephen Fry asked the late Apple founder Steve Jobs if the story was true. “Sadly not,” said Jobs, “but God, I wish it were.”

For more information visit www.bletchleypark.gov.uk

See also here.

You may already be aware Queen Elizabeth out of the goodness of her heart issued a “mercy pardon” for Alan Turing almost 60 years after he committed suicide when the British courts had him neutered for the heinous crime of being a grossly indecent homosexual: here.

How young songbirds learn singing


A baby house finch and its father. Just like humans, baby birds learn to vocalize by listening to adults. Credit: iStockphoto.com

From Emory University in the USA:

Doing the math for how songbirds learn to sing

December 20, 2012

(Phys.org)—Scientists studying how songbirds stay on key have developed a statistical explanation for why some things are harder for the brain to learn than others.

“We’ve built the first mathematical model that uses a bird’s previous sensorimotor experience to predict its ability to learn,” says Emory biologist Samuel Sober. “We hope it will help us understand the math of learning in other species, including humans.” Sober conducted the research with physiologist Michael Brainard of the University of California, San Francisco. Their results, showing that adult birds correct small errors in their songs more rapidly and robustly than large errors, were published in the Proceedings of the National Academy of Sciences (PNAS).

Sober’s lab uses Bengalese finches as a model for researching the mechanisms of how the brain learns to correct vocal mistakes. Just like humans, baby birds learn to vocalize by listening to adults. Days after hatching, Bengalese finches start imitating the sounds of adults. “At first, their song is extremely variable and disorganized,” Sober says. “It’s baby talk, basically.”

The young finches keep practicing, listening to their own sounds and fixing any mistakes that occur, until eventually they can sing like their elders. Young birds, and young humans, make a lot of big mistakes as they learn to vocalize. As birds and humans get older, the variability of mistakes shrinks. One theory contends that adult brains tend to screen out big mistakes and pay more attention to smaller ones. “To correct any mistake, the brain has to rely on the senses,” Sober explains. “The problem is, the senses are unreliable. If there is noise in the environment, for example, the brain may think it misheard and ignore the sensory experience.” The link between variability and learning may explain why youngsters tend to learn faster and why adults are more resistant to change.

A detailed 3D image of a bird’s voice box has been created by scientists investigating how the animals sing: here.

How Can Birds Sing Without Pausing To Breathe? Here.

December 2013: New findings from the University of Washington show that consistent individual differences exist not only for how aggressive individual song sparrows are but also for how much they use their signals to communicate their aggressive intentions: here.

Why were dinosaurs big?


This video is called Tribute to Theropod Dinosaurs.

From the Geological Society of America:

Were dinosaurs destined to be big? Testing Cope’s rule

GSA Annual Meeting Presentation: Testing Cope’s rule and the existence of an upper bound for body size in non-avian dinosaurs

Boulder, CO, USA – In the evolutionary long run, small critters tend to evolve into bigger beasts — at least according to the idea attributed to paleontologist Edward Cope, now known as Cope’s Rule. Using the latest advanced statistical modeling methods, a new test of this rule as it applies dinosaurs shows that Cope was right — sometimes.

“For a long time, dinosaurs were thought to be the example of Cope’s Rule,” says Gene Hunt, curator in the Department of Paleobiology at the National Museum of Natural History (NMNH) in Washington, D.C. Other groups, particularly mammals, also provide plenty of classic examples of the rule, Hunt says.

To see if Cope’s rule really applies to dinosaurs, Hunt and colleagues Richard FitzJohn of the University of British Columbia and Matthew Carrano of the NMNH used dinosaur thigh bones (aka femurs) as proxies for animal size. They then used that femur data in their statistical model to look for two things: directional trends in size over time and whether there were any detectable upper limits for body size.

“What we did then was explore how constant a rule is this Cope’s Rule trend within dinosaurs,” said Hunt. They looked across the “family tree” of dinosaurs and found that some groups, or clades, of dinosaurs do indeed trend larger over time, following Cope’s Rule. Ceratopsids and hadrosaurs, for instance, show more increases in size than decreases over time, according to Hunt. Although birds evolved from theropod dinosaurs, the team excluded them from the study because of the evolutionary pressure birds faced to lighten up and get smaller so they could fly better.

As for the upper limits to size, the results were sometimes yes, sometimes no. The four-legged sauropods (i.e., long-necked, small-headed herbivores) and ornithopod (i.e., iguanodons, ceratopsids) clades showed no indication of upper limits to how large they could evolve. And indeed, these groups contain the largest land animals that ever lived.

Theropods, which include the famous Tyrannosaurus rex, on the other hand, did show what appears to be an upper limit on body size. This may not be particularly surprising, says Hunt, because theropods were bipedal, and there are physical limits to how massive you can get while still being able to move around on two legs.

Hunt, FitzJohn, and Carrano will be presenting the results of their study on the afternoon of Sunday, Nov. 4, at the annual meeting of The Geological Society of America in Charlotte, North Carolina, USA.

As for why Cope’s Rule works at all, that is not very well understood, says Hunt. “It does happen sometimes, but not always,” he added. The traditional idea that somehow “bigger is better” because a bigger animal is less likely to be preyed upon is naïve, Hunt says. After all, even the biggest animals start out small enough to be preyed upon and spend a long, vulnerable, time getting gigantic.