Science Sunday #11
Posted by Don McLenaghen on August 28, 2011
– and on the seventh day we learn.
Each week I hope to give a synopsis of the interesting science stories I have heard on my plethora of science podcasts I listen to each week plus anything I pick up scanning the inter-web. This week’s top stories:
Words of the Week:
Neutron Star – A type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event.
Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger mass than protons. Neutron stars are very hot and are supported against further collapse by quantum degeneracy pressure due to the Pauli Exclusion Principle. This principle states that no two neutrons can occupy the same place and quantum state simultaneously.
The neutron star’s density varies from below 1×109 kg/m3 in the crust, increasing with depth to above 7×1017 kg/m3 deeper inside. This density is approximately equivalent to the mass of the entire human population compressed to the size of a sugar cube.`
Pulsar – A highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name. Because neutron stars are very dense objects, the rotation period and thus the interval between observed pulses is very regular. The observed periods of their pulses range from 1.4 milliseconds to 8.5 seconds.
Magnetar – A type of pulsar star with an extremely powerful magnetic field, the decay of which powers the emission of copious amounts of high-energy electromagnetic radiation, particularly X-rays and gamma rays.
The density of a magnetar is such that a thimbleful of its substance, sometimes referred to as neutronium, would have a mass of over 100 million tons. Magnetars also rotate rapidly, with most magnetars completing a rotation once every one to ten seconds.
Their strong magnetic fields decay after about 10,000 years, after which activity and strong X-ray emission cease.
Magnetars are primarily characterized by their extremely powerful magnetic field, which can often reach the order of 10 gigateslas. The magnetic field of a magnetar would be lethal even at a distance of 1000 km, tearing tissues due to the diamagnetism of water.
Strange Survival of Irregular Verbs –
An historical study of the development of irregular verbs in the hundreds of Romance languages including French, Spanish, Italian, Portuguese, Romanian and Catalan has revealed how these structures survive.
Professor Martin Maiden of Oxford’s Faculty of Linguistics Philology & Phonetics and the Faculty of Medieval and Modern Languages led the four year study which was funded by the Arts and Humanities Research Council.
There is usually a good historical reason why irregularities appear in a language, Professor Maiden adds, but often the original causes disappear, leaving behind apparently inexplicable irregularities.
Some forms of the French verb mourir (to die) have the spelling ‘eu’ rather than ‘ou’ (for example je meurs — ‘I die’ — against nous mourons — ‘we die’. This difference is due to sound changes at an earlier stage of the language but the pattern of irregularity created by these changes then provides a template into which other kinds of irregularity, which cannot be explained by sound change, are attracted.
The irregular forms of the verb aller (to go, for example je vais — ‘I go’ — against nous allons — ‘we go’) can be shown to have followed this pattern.
Professor Maiden believes that the Romance languages provide ‘an extraordinarily rich and detailed field for the study of how and why language changes’.
Bacteria-Produced Wires –
The discovery of a fundamental, previously unknown property of microbial nanowires in the bacterium Geobacter sulfurreducens that allows electron transport across long distances could revolutionize nanotechnology and bioelectronics, says a team of physicists and microbiologists at the University of Massachusetts Amherst.
Bacteria use pili, as the threads are known, to connect with other bacteria, and they also conduct electricity, says microbiologist Derek Lovley at the University of Massachusetts at Amherst.
Lovley’s team sheared some from Geobacter bacteria to study their properties in isolation. They found that conductivity increases with pH and as temperatures fall – just as in metals. The team then engineered the bacteria to boost pili production, which in turn boosted the overall conductivity of Geobacter biofilms.
The researchers report that this is the first time metallic-like conduction of electrical charge along a protein filament has been observed.
Lovley says, “The ability of protein filaments to conduct electrons in this way is a paradigm shift in biology and has ramifications for our understanding of natural microbial processes as well as practical implications for environmental clean-up and the development of renewable energy sources.”
New Anti-Censorship Scheme –
A radical new approach to thwarting Internet censorship would essentially turn the whole web into a proxy server, making it virtually impossible for a censoring government to block individual sites.
The system is called Telex, and it is the brainchild of computer science researchers at the University of Michigan and the University of Waterloo in Canada.
Today’s typical anti-censorship schemes get users around site blocks by routing them through an outside server called a proxy. But the censor can monitor the content of traffic on the whole network, and eventually finds and blocks the proxy, too.
Here’s how Telex would work:
Users install Telex software. J. Alex Halderman, assistant professor of computer science and engineering at U-M and one of Telex’s developers, envisions they could download it from an intermittently available website or borrow a copy from a friend.
Internet Service Providers (ISPs) outside the censoring nation deploy equipment called Telex stations.
When a user wants to visit a blacklisted site, he or she would establish a secure connection to an HTTPS website, which could be any password-protected site that isn’t blocked. This is a decoy connection. The Telex software marks the connection as a Telex request by inserting a secret-coded tag into the page headers. The tag utilizes a cryptographic technique called “public-key steganography.”
“Steganography is hiding the fact that you’re sending a message at all,” Halderman said. “We’re able to hide it in the cryptographic protocol so that you can’t even tell that the message is there.”
The user’s request passes through routers at various ISPs, some of which would be Telex stations. These stations would hold a private key that lets them recognize tagged connections from Telex clients. The stations would divert the connections so that the user could get to any site on the Internet.
Under this system, large segments of the Internet would need to be involved through participating ISPs.
The researchers are at the proof-of-concept stage. They’ve developed software for researchers to experiment with. They’ve put up one Telex station on a mock ISP in their lab. They’ve been using it for their daily web browsing for the past four months and have tested it with a client in Beijing who was able to stream YouTube videos even though the site is blocked there.
Gender inequality in “overworked” labour –
Jobs that come with large paychecks but long work hours are slowing the gains women have made since the late 70s in narrowing the gender wage gap.
A study by sociologists from Indiana University and Cornell University finds that the growing trend of overworking — working 50 hours a week or more — is partly responsible for the slowdown Americans have experienced since the mid-1990s in the convergence of the gender gap in pay. The gap between the percentage of women working full-time compared to men has shrunk during the past 30 years but the gender gap involving long working hours has changed little and remains large.
“Women, even when employed full time, typically have more family obligations than men,” said IU sociologist Youngjoo Cha.
The study, using data collected by the U.S. Census Bureau, finds the relative hourly wage of overworkers compared to full-time workers has increased substantially over the past three decades. Because a greater percentage of male workers are overworking, this change benefited men more than women.
More about the study:
In 1979, 15 percent of men and 3 percent of women worked 50 hours or more per week. These percentages peaked in the late 1990s at 19 percent of men and 7 percent of women.
The real wages of men who worked 50 hours or more per week increased 54 percent between 1979 and 2009. The wages of women who worked the same hours increased, too, by 94 percent.
The wages of standard full-time workers (35 or more hours, but less than 50 hours) increased 13 percent for men and 46 percent for women between the same years.
The rising price of overwork slowed the decrease in the gender wage gap by 9.2 percent between 1979 and 2007. The effect is large enough to offset the gains achieved by narrowing the education gap.
Overwork compensation can be compared to standard full-time wages by breaking them down into an hourly wage. In 1979, men who overworked earned 14 percent less than men who worked fulltime once their pay was spread over the longer hours, and women saw a 19 percent penalty. Now men and women both earn a six percent premium in this hourly wage comparison.
Most of the decline in the gender gap in wages occurred in the 1980s.
Women now earn an estimated 81 percent of what men earn.
Climate cycles are driving wars –
In the first study of its kind, researchers have linked a natural global climate cycle to periodic increases in warfare. The arrival of El Niño, which every three to seven years boosts temperatures and cuts rainfall, doubles the risk of civil wars across 90 affected tropical countries, and may help account for a fifth of worldwide conflicts during the past half-century, say the authors. The paper, written by an interdisciplinary team at Columbia University’s Earth Institute, appears in the current issue of the leading scientific journal Nature.
In recent years, historians and climatologists have built evidence that past societies suffered and fell due in connection with heat or droughts that damaged agriculture and shook governments. This is the first study to make the case for such destabilization in the present day, using statistics to link global weather observations and well-documented outbreaks of violence.
The cycle known as the El Niño-Southern Oscillation, or ENSO, is a periodic warming and cooling of the tropical Pacific Ocean. This affects weather patterns across much of Africa, the Mideast, India, southeast Asia, Australia, and the Americas, where half the world’s people live. During the cool, or La Niña, phase, rain may be relatively plentiful in tropical areas; during the warmer El Niño, land temperatures rise, and rainfall declines in most affected places. Interacting with other factors including wind and temperature cycles over the other oceans, El Niño can vary dramatically in power and length. At its most intense, it brings scorching heat and multi-year droughts. (In higher latitudes, effects weaken, disappear or reverse)
The scientists tracked ENSO from 1950 to 2004 and correlated it with onsets of civil conflicts that killed more than 25 people in a given year. The data included 175 countries and 234 conflicts, over half of which each caused more than 1,000 battle-related deaths. For nations whose weather is controlled by ENSO, they found that during La Niña, the chance of civil war breaking out was about 3 percent; during El Niño, the chance doubled, to 6 percent. Countries not affected by the cycle remained at 2 percent no matter what. Overall, the team calculated that El Niño may have played a role in 21 percent of civil wars worldwide—and nearly 30 percent in those countries affected by El Niño.
The authors say they do not know exactly why climate feeds conflict. “But if you have social inequality, people are poor, and there are underlying tensions, it seems possible that climate can deliver the knockout punch,” said Hsiang. When crops fail, people may take up a gun simply to make a living, he said. Kyle C. Meng, a sustainable-development Ph.D. candidate and the study’s other author, pointed out that social scientists have shown that individuals often become more aggressive when temperatures rise, but he said that whether that applies to whole societies is only speculative.
Domesticated Animal Populations Skyrocket –
In 1960, there were just over three billion people alive in the world; now there are close to seven billion. So the global population of humans has more than doubled in 50 years. But at the same time, people around the world have demanded more and more meat. So what has that meant for global livestock populations? Massive, massive growth.
In 1961, there were 3.9 billion chickens on Earth, just over one per person. Now there are 19 billion, according to UN data analyzed by The Economist. That’s three for every person alive. The next most populous livestock is cattle; there are 1.4 billion of them. Wild animals, meanwhile, have not fared as well. Since 1960, the global population of wild animals has tumbled by a quarter.
The Diamond Planet –
A once-massive star that’s been transformed into a small planet made of diamond: that’s what astronomers think they’ve found in our Milky Way.
The discovery, reported in Science, was made by an international research team led by Professor Matthew Bailes, Pro Vice-Chancellor (Research) at Swinburne University of Technology in Melbourne and the ‘Dynamic Universe’ theme leader in a new wide-field astronomy initiative, the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO).
For the newly discovered pulsar, known as PSR J1719-1438, the astronomers noticed that the arrival times of the pulses were systematically modulated. They concluded that this was due to the gravitational pull of a small companion planet, orbiting the pulsar in a binary system.
Pulsar J1719-1438 is a very fast-spinning pulsar — what’s called a millisecond pulsar. Amazingly, it rotates more than 10,000 times per minute, has a mass of about 1.4 times that of our Sun but is only 20 km in diameter. About 70 per cent of millisecond pulsars have companions of some kind. Astronomers think it is the companion that, in its star form, transforms an old, dead pulsar into a millisecond pulsar by transferring matter and spinning it up to a very high speed. The result is a fast-spinning millisecond pulsar with a shrunken companion — most often a so-called white dwarf.
But pulsar J1719-1438 and its companion are so close together that the companion can only be a very stripped-down white dwarf, one that has lost its outer layers and over 99.9 per cent of its original mass.
“This remnant is likely to be largely carbon and oxygen; the density means that this material is certain to be crystalline: that is, a large part of the star may be similar to a diamond.