Not a Quirk But a Quark ... a Quark Star!

Super-luminous stellar explosion observed via Caltech's Palomar Observatory, possibly resulting in a quark star

Illustration of a supernova explosion.
Credit and Larger Version

Astronomers recently announced that they have found a novel explanation for a rare type of super-luminous stellar explosion that may have produced a new type of object known as a quark star.

Three exceptionally luminous supernovae explosions have been observed in recent years. One of them was first observed using a robotic telescope at the California Institute of Technology's (Caltech) Palomar Observatory.

Data collected with Palomar's Samuel Oschin Telescope was transmitted from the remote mountain site in southern California to astronomers via the High-Performance Wireless Research and Education Network (HPWREN), funded by the National Science Foundation (NSF). The Nearby Supernova Factory research group at the Lawrence Berkeley Laboratory reported the co-discovery of the supernova, known as SN2005gj.

Researchers in Canada have analyzed this, along with two other supernovae, and believe that they each may be the signature of the explosive conversion of a neutron star into a quark star.

These three supernovae, each 100 times brighter than a typical supernova, have been difficult to explain. The Canadian research team thinks the explosions herald the creation of a previously unobserved and new class of objects, designated as quark stars.

A quark star is a hypothetical type of star composed of ultra dense quark matter. Quarks are the fundamental components of protons and neutrons, which make up the nucleus of atoms. The most dense objects known to exist today are neutron stars--stars composed entirely of tightly packed neutrons. A typical neutron star is some 16 miles across, yet has a mass one and a half times the mass of our Sun.

Neutron stars are formed when a massive star undergoes a supernova explosion at the end of its life. The question is, is a neutron star indeed the most dense object that exists? It is thought that if the neutrons are too tightly packed--if what scientists consider a neutron star is too dense--the resulting instability may lead to a further collapse, resulting in a second explosion and the creation of a quark star. The energy that powers that second explosion comes from neutrons breaking down into their component parts: quarks.

Further observations should help to confirm or defeat the hypothesis of quark stars, but in either case, the use of a high-speed network like HPWREN helps astronomers across the world explore the frontiers of science.

About HPWREN

HPWREN is an NSF-funded network research project, which also functions as a collaborative cyberinfrastructure on research, education and first responder activities. It includes creating, demonstrating and evaluating a non-commercial, prototype, high-performance, wide-area, wireless network in San Diego, Riverside and Imperial counties in California. The network includes backbone nodes at the University of California, San Diego, and San Diego State University campuses, and a number of "hard to reach" areas in remote environments.

Caltech's Palomar Observatory and the nearby Supernova Factory Research Group at the Lawrence Berkeley Laboratory have also been supported in part by NSF.

--	Lisa-Joy Zgorski, (703) 292-8311 lisajoy@nsf.gov

Original here

Citizen Astronomy

By Janet Raloff

Voorwerp's DiscovererA month after Galaxy Zoo got started, this primary-school teacher had already discovered what may be a totally novel type of celestial object. Edd Edmondson

When a small band of astronomers launched Galaxy Zoo almost a year ago, they didn’t know what to expect. They had a boatload of photos (scientific translation: roughly 1 million) depicting never-before-seen patches of the sky. These researchers and their colleagues lacked the time and stamina to sequentially sift through the images, one by one, classifying the galaxies they showed.

In theory, computers could have been tasked with screening those photos. But image-processing software doesn’t yet hold a candle to our brains’ accuracy at evaluating whether shapes match — or don’t — the samples they’ve been trained to compare.

So the researchers took a gamble. Not a terribly expensive one. But there was, theoretically, science on the line.

They loaded all of the images onto a computer along with a little training session and then, last July, invited all comers to log on and characterize the types of galaxies present in a randomly selected series of photographs that the site served up. All had been taken as part of the Sloan Digital Sky Survey.

From a scientific standpoint, Galaxy Zoo started paying dividends almost from day one. “This is not something we expected,” notes Chris Lintott, an Oxford University scientist and “zookeeper.” The hope was that hundreds of people would log on. To date, almost 150,000 have.

And the idea that many of the images might one day be categorized illustrates how low the zookeepers’ expectations had been. On average, each of the images on the site has already been seen and characterized by 50 people. Those 50 million photo evaluations “is simply fantastic,” Lintott says, “and illustrates for us one of the huge advantages of getting the public involved. It gives us an error bar on the classifications.”

Even if the world’s best characterizer was cataloging a million galaxies, there’s no way to evaluate whether he or she got sloppy mid-way through. You’d either have to accept the individual’s assessment or not. “Here we have multiple independent classifications,” Lintott observes. And by essentially averaging their assessments — and, potentially identifying outliers — the experts can tabulate the viewers’ apparent reliability. In fact, if there’s no clear consensus, that may itself point to something the experts need to see for themselves.

Moreover, Lintott observes, “We soon realized the public is very good at finding weird things.”

One of the first to emerge — now known as Hanny’s Voorwerp — may be the only known celestial object of its kind in the universe. Lintott will be the lead author of a research paper that formally announces the weird object’s discovery. He expects to submit it next week for publication in the Monthly Notices of the Royal Astronomical Society. This journal, which neither comes out monthly nor runs notices of the RAS, is the leading British site for astronomical publishing.

To show how much he and his colleagues value the nonscientist who first brought the object to their attention (a Dutch primary school teacher named Hanny van Arkel), they will make her a co-author on their paper.

The Voorwerp was hardly the only oddity zoogoers identified. “We’ve now collected a long list of weird things,” Lintott says. Some are objects that appear to be so-called gravitational lenses. “And we have this wonderful object called the blue banana.” He acknowledges having “no idea what it is yet. So at some point I’ve got to spend a few days trying to find out.”

But that’s when he gets a spare moment. Besides having full-time jobs, Lintott and the other zookeepers have been scurrying around at a furious pace to make use of the steady stream of data being served up by the public zoogoers. “We’ve already submitted four papers to the journals based on Galaxy Zoo data,” Lintott told me last night, “and there are about 25 separate research projects underway” based on GZ assessments.

So successful was Galaxy Zoo, that its developers will shortly roll out Galaxy Zoo Two. It will “ask the public to make more detailed classifications than we have before of the brightest quarter-of-a-million galaxies or so,” Lintott says. And the new zoo will make it easier to identify the more unusual objects. Viewers can simply tag images they think deserve professional follow-up.

The best thing about this is that it engages the public in science and lets former outsiders experience not only the wonder of discovery but an ability to interact online with scientists and fellow enthusiasts. Actually, it sounds a lot like being a Science News reporter.

Original here

Big haul of Crohn's genes shows disease complexity

By Ben Hirschler

LONDON (Reuters) - Scientists have linked 32 genetic variations to Crohn's disease, a bowel disorder, highlighting the complexity of many common diseases and the difficulties facing researchers seeking treatments.

Scientists said on Sunday that new research had tripled the number of genetic regions implicated in Crohn's, the most common form of inflammatory bowel disease, and many more were probably still undiscovered.

"These explain only about a fifth of the genetic risk, which implies that there may be hundreds of genes implicated in the disease, each increasing susceptibility by a small amount," said Jeffrey Barrett from the Wellcome Trust Centre for Human Genetics at the University of Oxford, who led the research.

Scientists have known for years that genes, along with environmental factors, play a role in increasing the risk that people will develop many common problems like asthma, high blood pressure, rheumatoid arthritis, cancer and heart disease.

But they are still trying to work out which parts of the genome -- the 3 billion sub-units of DNA in our cells -- are actually responsible.

One way to find out is to conduct genome-wide association studies, in which genetic markers from thousands of volunteers are analyzed in order to identify genetic differences between diseased and healthy individuals.

The latest picture to emerge for Crohn's, which was reported in the journal Nature Genetics, represents the most complete picture yet assembled of the genetic influences on risk of a common disease.

Significantly, three of the individual genes that have been implicated in Crohn's have previously been shown to influence risk of type 1 diabetes and asthma, suggesting a possible common genetic mechanism underlying these disorders.

Crohn's disease affects between one in 500 and one in 1000 people in the industrialized world, causing inflammation, pain, ulcers and diarrhea.

Modern biotech drugs like Abbott Laboratories's Humira, UCB's Cimzia and Johnson & Johnson's Remicade can help, but many patients end up needing surgery.

By pinpointing genes linked to the condition, researchers hope to find fresh targets for new drugs.

One of the most promising is thought to be the CCR6 gene, which is believed to be part of the signaling machinery that causes white blood cells in the gut to become over-active, leading to inflammation.

The same white blood cells are also present in inflamed joints, implying that CCR6 may play a role in rheumatoid arthritis as well, making it of added interest to the pharmaceutical industry, Barrett and colleagues said.

Original here

Researchers re-create pre-Columbian sounds

Roberto Velazquez, an expert in pre-Columbian sounds, plays a replica of a flute in Mexico City, April 17, 2008. The 66-year-old mechanical engineer has given his career to recreating the sounds of his pre-Columbian ancestors, producing hundreds of replicas of whistles, flutes and wind instruments unearthed in Mexico's ruins.

By Julie Watson

MEXICO CITY - Scientists were fascinated by the ghostly find: a human skeleton buried in an Aztec temple with a clay, skull-shaped whistle in each bony hand.

But no one blew into the noisemakers for nearly 15 years. When someone finally did, the shrill, windy screech made the spine tingle.

If death had a sound, this was it.

Roberto Velazquez believes the Aztecs played this mournful wail from the so-called Whistles of Death before they were sacrificed to the gods.

The 66-year-old mechanical engineer has devoted his career to recreating the sounds of his pre-Columbian ancestors, producing hundreds of replicas of whistles, flutes and wind instruments unearthed in Mexico’s ruins.

For years, many archaeologists who uncovered ancient noisemakers dismissed them as toys. Museums relegated them to warehouses. But while most studies and exhibits of ancient cultures focus on how they looked, Velazquez said the noisemakers provide a rare glimpse into how they sounded.

“We’ve been looking at our ancient culture as if they were deaf and mute,” he said. “But I think all of this is tied closely to what they did, how they thought.”

Velazquez is part of a growing field of study that includes archaeologists, musicians and historians. Medical doctors are interested too, believing the Aztecs may have used sound to treat illnesses.

Noisemakers made of clay, turkey feathers, sugar cane, frog skins and other natural materials were an integral part of pre-Columbian life, found at nearly every Mayan site.

Alexandre Meneghini / ASSOCIATED PRESS A replica of a skull shaped whistle, created by pre-Columbian sounds expert Roberto Velazquez, in Mexico City.

The Aztecs sounded the low, foghorn hum of conch shells at the start of ceremonies and possibly during wars to communicate strategies. Hunters likely used animal-shaped ocarinas to produce throaty grunts that lured deer.

The modern-day archaeologists who came up with the term Whistles of Death believe they were meant to help the deceased journey into the underworld, while tribes are said to have emitted terrifying sounds to fend off enemies, much like high-tech crowd-control devices available today.

Experts also believe pre-Columbian tribes used some of the instruments to send the human brain into a dream state and treat certain illnesses. The ancient whistles could guide research into how rhythmic sounds alter heart rates and states of consciousness.

Among Velazquez’s replicas are those that emit a strange cacophony so strong that their frequency nears the maximum range of human hearing.

Chronicles by Spanish priests from the 1500s described the Aztec and Mayan sounds as sad and doleful, although these may have been only what was played in their presence.

“My experience is that at least some pre-Hispanic sounds are more destructive than positive, others are highly trance-evocative,” said Arnd Adje Both, an expert in pre-Hispanic music archaeology who was the first to blow the Whistles of Death found in the Aztec skeleton’s hands. “Surely, sounds were used in all kind of cults, such as sacrificial ones, but also in healing ceremonies.”

Sounds still play an important role in Mexican society. A cow bell announces the arrival of the garbage truck outside Mexico City homes. A trilling, tuneless flute heralds the knife sharpener’s arrival. A whistle emitting cat meows says the lottery ticket seller is here.

But pre-Columbian instruments often end up in a warehouse, Velazquez said, “and I’m talking about museums around the world doing this, not just here.”

That’s changing, said Tomas Barrientos, director of the archaeology department at Del Valle University of Guatemala.

Alexandre Meneghini / ASSOCIATED PRESS A replica of a flute, created by pre-Columbian sounds expert Roberto Velazquez.

“Ten years ago, nothing was known about this,” he said. “But with the opening up of museum collections and people’s private collections, it’s an area of research that is growing in importance.”

Velazquez meticulously researches each noisemaker before replicating it. He travels across Mexico to examine newly unearthed wind instruments, some dating back to 400 B.C. and shaped like animals or deities. He studies reliefs and scans 500-year-old Spanish chronicles.

But making replicas is only part of the work. Then he has to figure out how to play them. He’ll blow into some holes and plug others, or press the instrument to his lips and flutter his tongue. Sometimes he puts the noisemaker inside his mouth and blows, fluctuating the air from his lungs.

He experimented with one frog-shaped whistle for a year before discovering its inner croak.

Renowned archaeologist Paul Healy, who made an important discovery of Mayan instruments in Belize in the 1980s, said many of the originals still work.

“A couple of these instruments we found were broken, which was great because we could actually see the construction of them, the actual technology of building a sound chamber out of paper-thin clay,” he said.

Click for related content

Scientists to unlock sweet secrets of chocolate Why shopping — and adventure — feel so good 'X-Men' frogs sprout claws on demand

Still, their exact sounds will likely remain a mystery.

“When you blow into them, you still can get notes from them, so you could figure out what the range was,” Healy said. “But what we don’t have is sheet music to give us a more accurate picture of what it sounded like.”

© 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Original here

Weird science

Demonstrating the electrification of hair in 1930

A POINT OF VIEW

Explosions. Bunsen burners. Adoring crowds in evening dress - or school uniform - eyes wide with wonderment. Can we recapture the excitement of science, asks historian Lisa Jardine.

Inside many of our historic buildings, spaces survive which seem to hold particularly strong memories of events that took place within them. One of my favourites is the Faraday Lecture Theatre at the Royal Institution in London, one of our oldest establishments dedicated to the promotion of science.

The refurbished lecture hall

Since shortly after the Institution's foundation in 1799, the world's greatest scientific communicators have stood in front of its baize-covered desk, at the centre of the steeply-raked 300-seat theatre to enthral the general public with their ideas and experiments.

What a contrast with today. Last week, Ofsted reported that at both primary and secondary school level, science lessons were dull and there were not enough practical experiments. Teachers no longer entertain classes with explosions of powdered magnesium; gone are the bunsen burners for heating noxious mixtures in fragile test-tubes.

"Science is a fascinating and exciting subject," said Chief inspector Christine Gilbert. "Yet for many pupils, it lacks appeal because of the way that it is taught."

Crowd pleasers

It was in the Faraday Lecture Theatre, in June 1903, that French scientist Pierre Curie and his Polish wife Marie Sklodowska Curie demonstrated the remarkable properties of their newly discovered element, radium.

Marie and Pierre in 1903

The occasion was one of the Institution's celebrated Friday evening discourses, a fashionable event for which those who attended were expected to don full evening dress, and which caused such congestion on Piccadilly that Albemarle Street, on which the Institution stands, had to be designated the first one-way street in London, to cope with the crush of carriages.

The Curies were the scientific stars of the moment: everyone in London wanted to meet them. In the packed theatre, eminent scientists rubbed shoulders with leading members of London's high society, craning their necks in anticipation.

Actually, it was Pierre Curie who conducted the radium experiments, since propriety and the rules of the Royal Institution prevented a woman from participating in a Royal Institution discourse. Most of those present, however, understood that this research had been carried out by a perfectly-matched scientific partnership, whose complementary abilities were clearly evidenced by their many published papers.

By 1903, the Curies had produced an impressive sequence of joint papers on the two new radioactive elements they had discovered - polonium and radium - but both Marie and Pierre had also published key results on both the physics and chemistry of radioactivity independently.

At the end of that year, indeed, they were jointly awarded the Nobel Prize for Physics, "in recognition of the extraordinary services they have rendered by their joint researches on the radiation phenomena discovered by Professor Henri Becquerel".

Own lab rat

As a sign of the high regard in which she was held, Marie sat in the front row of the Faraday lecture theatre, alongside the most senior scientist present at that occasion, the former President of the Royal Society and towering figure in the investigation of electricity, Lord Kelvin.

The lecture theatre had to be decontaminated, because of the dangerous level of radiation Hear Radio 4's A Point of View

In a partially darkened room, Pierre showed how radium emitted a ghostly light. He placed a piece of radium on a photographic plate which had been wrapped in thick layers of newspaper. Removing the paper, Pierre Curie revealed how the clear image of the radium had been transmitted through its wrappings, on to the plate.

Finally, rolling up his sleeve, he showed a livid red area of damaged skin, where he had bound a sample of radium wrapped in a thin layer of rubber to his arm for 10 hours. Marie, he explained, had suggested that this property of burning the skin might make radium a useful treatment for cancer.

As he moved his precious radium samples around, Pierre Curie's fingers fumbled badly. So incapacitated was he by his badly scarred hands and a general feeling of fatigue and debilitation, that he had not been able to tie his dress tie before the lecture. Neither he nor his wife was aware of the lasting damage being caused to their health by repeated handling of radioactive substances. Neither took any precautions when working at close quarters with radium.

So in this case, one of the lasting memories I began with was a real one: years after Pierre's Royal Institution performance, it was found that the effects of his mishandling of his material still lingered on the premises - the lecture theatre had to be decontaminated, because of the dangerous level of radiation.

Rule book

It is hard today to decide which attitude on that celebrated occasion was the more blinkered: the absolute inability publicly to recognise a great woman's scientific achievement, or the assembled company's unreserved celebration of radioactivity. For now, I'll stay with the former.

Tools of the trade

Among those in the admiring audience at the Curies' lecture was another distinguished woman scientist, the physicist Hertha Ayrton. A year earlier she had been the first woman proposed for candidature as a Fellow of the even more prestigious Royal Society, for her "long series of experiments on direct [electrical] current arc, leading to many new facts and explanations".

After a flurry of activity on the part of the existing Fellows it was agreed that Hertha Ayrton's candidature was ineligible, because she was a married woman. Even had she been single, it was decided that "the Statutes of the Society are framed on the footing that only men can be elected, and we think that no woman can be properly elected as a Fellow, without some alteration in the Statutes".

Hertha Ayrton and Marie Curie - encouraged by the statutes of the Royal Institution to attend its lectures, but not allowed to take part in its serious business - became close friends. When, in 1909, the Westminster Gazette attributed the discovery of radium to Pierre Curie, it was Hertha who protested in a letter to the editor.

"Errors are notoriously hard to kill," she wrote. "But an error that ascribes to a man what was actually the work of a woman has more lives than a cat."

Science can be fun

But let's go back, to all that messing about with dangerous substances - substances we now know could kill - for the entertainment of the public in the Faraday lecture theatre in the 1900s.

Pupils want practical science lessons to make the subject more fun

From the beginning, the Royal Institution was a place where science was both useful and fun. Its mission was declared to be: "Teaching the application of Science to the common Purposes of Life". And the public flocked to its scientific demonstrations throughout the 19th Century.

So why are so many people today happy to admit that they find science difficult and dull? Some of the blame may be laid at the doors of our education system, as the Ofsted report suggested. But there must be more to the flight from science.

People who would never admit to a lack of understanding of art or literature are happy to confess to total incomprehension where science is concerned. Yet our lives today depend as never before upon the outcomes of innovative science and technology. Without medical science, our lives would be shorter and more painful; without physics and chemistry, domestic conveniences that ease our everyday lives could never have been developed.

If, however, the reason for the general public's disenchantment with science is to be laid at the door of scientists unable or unprepared to communicate their subject so as to engage the interest and enthusiasm of non-specialists, then the Royal Institution is continuing a long tradition actively to counter such a trend.

You should be able to say 'where shall we go tonight? I know, let's go to the Royal Institution' Susan Greenfield

It has just reopened after a major refurbishment of its original Albemarle Street premises by architect Terry Farrell - a refurbishment which thankfully leaves the Faraday lecture theatre improved but fundamentally unchanged, while transforming the rest of the buildings into an Aladdin's cave of enticing spaces fostering science education and communication.

In her address to the distinguished audience of scientists and friends gathered at the official reopening, director Susan Greenfield expressed the hope that evenings at the RI might once again be considered as thrilling a prospect as going to the cinema or out to dinner. "You should be able to say 'where shall we go tonight? I know, let's go to the Royal Institution'."

And if you do decide to attend one of those captivating, cutting-edge Friday evening discourses, you can still enjoy arriving in evening dress, as you might for a night out at the opera. That is no longer mandatory - but it means that memories of the glory days of science still seem to hover over the Faraday lecture theatre.

---

Thanks for your comments.

Health and safety fears and the red tape of completing risk assessments are another reason why teachers are unwilling to conduct many of the more 'interesting' practical experiments.
Derek Charles, Worthing, England

One of my favourite memories of school was watching our chemistry teacher getting rather confused and mixing two chemicals which resulted in a small explosion. The "blast" was small enough that it didn't radiate beyond the teachers desk and so nowhere near any of the pupil desks, however several parents complained and the teacher was given a warning, even though every kid in the room thought it was great. The problem is that everything has to be wrapped in cotton wool now in case some overprotective parent sues the school, and when you cotton wool science it means no (or very simple = safe) experiments.
Olly, York, UK

The reason that sciences are failing is the growing acceptance for the arts. It is now a highly acceptable career path for children to go through their whole school life wanting to be an artist et. al. Years ago that talk would have been dismissed as drivel and pupils pushed towards the sciences not the arts
Adam Scarborough, Cheltenham

I always enjoyed watching the Royal Institutions Xmas lectures on TV as they really made science come alive. But then again when I was at school (not that long ago) I did physics, biology and chemistry as separate subjects. We also had a science club where we were challenged to do such experiments such as build the highest tower using paper and sellotape.
Karen, Didcot, UK

Science is finding out, then measuring. Science can't ALWAYS be fun, but maybe its significance is not always communicated well. Curiosity is the first step in science, and perhaps this is not encouraged enough!
Nigel Macarthur, London, England

When I was a kid (30 years ago) science was close enough to reality which made it easier to grasp. I am an engineer now and I have taught science/engineering and things have gotten so complex and intricate that to get someone to understand what is comparably at the same level as 30 years ago requires a much greater level of knowledge than before.
Francisco Lopez, Madrid

How can science be interesting if there is no chance to see and participate in experiments? You can't learn to play the violin by reading descriptions of someone else playing a violin. You have to 'do' science to learn it - even if that includes some things gone wrong. If a teacher doesn't enjoy science, they will convey their attitude no matter how they try not to. Then science become a course to get through, not to learn.
Richard Namon, Miami, USA

Original here

Quantum computing breakthrough arises from unknown molecule

WEST LAFAYETTE, Ind. -

A new hybrid atom
Download photo
caption below

The odd behavior of a molecule in an experimental silicon computer chip has led to a discovery that opens the door to quantum computing in semiconductors.

In a Nature Physics journal paper currently online, the researchers describe how they have created a new, hybrid molecule in which its quantum state can be intentionally manipulated - a required step in the building of quantum computers.

"Up to now large-scale quantum computing has been a dream," says Gerhard Klimeck, professor of electrical and computer engineering at Purdue University and associate director for technology for the national Network for Computational Nanotechnology.

"This development may not bring us a quantum computer 10 years faster, but our dreams about these machines are now more realistic."

The workings of traditional computers haven't changed since they were room-sized behemoths 50 years ago; they still use bits of information, 1s and 0s, to store and process information. Quantum computers would harness the strange behaviors found in quantum physics to create computers that would carry information using quantum bits, or qubits. Computers would be able to process exponentially more information.

If a traditional computer were given the task of looking up a person's phone number in a telephone book, it would look at each name in order until it found the right number. Computers can do this much faster than people, but it is still a sequential task. A quantum computer, however, could look at all of the names in the telephone book simultaneously.

Quantum computers also could take advantage of the bizarre behaviors of quantum mechanics - some of which are counterintuitive even to physicists - in ways that are hard to fathom. For example, two quantum computers could, in concept, communicate instantaneously across any distance imaginable, even across solar systems.

Albert Einstein, in a letter to Erwin Schrödinger in the 1930s, wrote that in a quantum state a keg of gunpowder would have both exploded and unexploded molecules within it (a notion that led Schrödinger to create his famous cat-in-a-box thought experiment).

This "neither here nor there" quantum state is what can be controlled in this new molecule simply by altering the voltage of the transistor.

Until now, the challenge had been to create a computer semiconductor in which the quantum state could be controlled, creating a qubit.

"If you want to build a quantum computer you have to be able to control the occupancy of the quantum states," Klimeck says. "We can control the location of the electron in this artificial atom and, therefore, control the quantum state with an externally applied electrical field."

The discovery began when Sven Rogge and his colleagues at Delft University of Technology in the Netherlands were experimenting with nano-scale transistors that show the effects of unintentional impurities, or dopants. The researchers found properties in the current-voltage characteristics of the transistor that indicated electrons were being transported by a single atom, but it was unclear what impurity was causing this effect.

Physicist Lloyd Hollenberg and colleagues at the University of Melbourne in Australia were able to construct a theoretical silicon-based quantum computer chip based on the concept of using an individual impurity.

"The team found that the measurements only made sense if the molecule was considered to be made of two parts," Hollenberg says. "One end comprised the arsenic atom embedded in the silicon, while the 'artificial' end of the molecule forms near the silicon surface of the transistor. A single electron was spread across both ends.

"What is strange about the 'surface' end of the molecule is that it occurs as an artifact when we apply electrical current across the transistor and hence can be considered 'manmade.' We have no equivalent form existing naturally in the world around us."

Klimeck, along with graduate student Rajib Rahman, developed an updated version of the nano-electronics modeling program NEMO 3-D to simulate the material at the size of 3 million atoms.

"We needed to model such a large number of atoms to see the new, extended quantum characteristics," Klimeck says.

The simulation showed that the new molecule is a hybrid, with the naturally occurring arsenic at one end in a normal spherical shape and a new, artificial atom at the other end in a flattened, 2-D shape. By controlling the voltage, the researchers found that they could make an electron go to either end of the molecule or exist in an intermediate, quantum, state.

This model was then made into an image by David Ebert, a professor of electrical and computer engineering at Purdue, and graduate student Insoo Woo.

Delft's Rogge says the discovery also highlights the current capabilities of designing electronic machines.

"Our experiment made us realize that industrial electronic devices have now reached the level where we can study and manipulate the state of a single atom," Rogge says. "This is the ultimate limit, you can not get smaller than that."

Writer: Steve Tally, (765) 494-9809, tally@purdue.edu

Sources: Gerhard Klimeck, (765) 494-9212, gekco@purdue.edu

Sven Rogge, +31 (0) 15 278 24 95, s.rogge@tudelft.nl

Lloyd Hollenberg, +61 3 8344 4210, lloydch@unimelb.edu.au

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

PHOTO CAPTION:
An international team has identified a new hybrid atom that could be used to develop quantum computers. This data visualization shows an electron density map of the material. The funnel- or vortex-shaped figure in the lower left is an arsenic atom, and the saucer-shaped image in the center is a map of an electron binding to various atoms (each dot represents one location). The yellow dots in the upper left-center are the electron in the quantum state. (Purdue University image/David Ebert)

A publication-quality photo is available at http://news.uns.purdue.edu/images/+2008/klimeck-arsenic.jpg

---

ABSTRACT

Gate Induced Quantum Confinement Transition of a Single Dopant Atom in a SiFinFET

G.P. Lansbergen1, R. Raham2, C.J. Wellard3, I. Woo2, J.Caro1, N. Collaert4, S. Biesemans4, G. Klimeck 2,5, LCL. Hollenberg3, and S. Rogge1

1Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands

2Network for Computational Nanotechnology, Purdue University, West Lafayette, Indiana 47907, USA

3Center for Quantum Computer Technology, School of Physics, University of Melbourne, VIC 3010, Australia

4InterUniversity Microelectronics Center (IMEC), Kapeldreef 75, 3001 Leuven, Belgium and

5Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA

The ability to structure devices at the atomic level has defined nanotechnology, however, obtaining true atomic level functionality requires engineering and control of the wavefunction of individual atoms. Here we experimentally investigate a single donor atom in a gated nanostructure. For the first time we observe evidence for a new hybrid molecule in the solid-state - a single electron bound in a double-well system formed by the proximity of nuclear (Coulomb) and gate-defined (quantum dot) confining potentials. The energy spectrum of single donors, located in the channel of FinFETs, were measured by transport spectroscopy and were shown to agree well with multimillion atom simulations of the complete system. In conjunction with the data, the theoretical analysis allowed us to identify the species of the donors (arsenic), their depth from the interface and furthermore provided an explicit determination of the degree of gate-controlled quantum confinement in each device.

Original here

Your brain lies to you

By Sam Wang and Sandra Aamodt

False beliefs are everywhere. Eighteen percent of Americans think the sun revolves around the earth, one poll has found. Thus it seems slightly less egregious that, according to another poll, 10 percent of us think that Senator Barack Obama, a Christian, is instead a Muslim. The Obama campaign has created a Web site to dispel misinformation. But this effort may be more difficult than it seems, thanks to the quirky way in which our brains store memories - and mislead us along the way.

The brain does not simply gather and stockpile information as a computer's hard drive does. Facts are stored first in the hippocampus, a structure deep in the brain about the size and shape of a fat man's curled pinkie finger. But the information does not rest there. Every time we recall it, our brain writes it down again, and during this re-storage, it is also reprocessed. In time, the fact is gradually transferred to the cerebral cortex and is separated from the context in which it was originally learned. For example, you know that the capital of California is Sacramento, but you probably don't remember how you learned it.

This phenomenon, known as source amnesia, can also lead people to forget whether a statement is true. Even when a lie is presented with a disclaimer, people often later remember it as true.

With time, this misremembering gets worse. A false statement from a noncredible source that is at first not believed can gain credibility during the months it takes to reprocess memories from short-term hippocampal storage to longer-term cortical storage. As the source is forgotten, the message and its implications gain strength. This could explain why, during the 2004 presidential campaign, it took weeks for the Swift Boat Veterans for Truth campaign against Senator John Kerry to have an effect on his standing in the polls.

Even if they do not understand the neuroscience behind source amnesia, campaign strategists can exploit it to spread misinformation.

They know that if their message is initially memorable, its impression will persist long after it is debunked. In repeating a falsehood, someone may back it up with an opening line like "I think I read somewhere" or even with a reference to a specific source.

In one study, a group of Stanford students was exposed repeatedly to an unsubstantiated claim taken from a Web site that Coca-Cola is an effective paint thinner. Students who read the statement five times were nearly one-third more likely than those who read it only twice to attribute it to Consumer Reports (rather than The National Enquirer, their other choice), giving it a gloss of credibility.

Adding to this innate tendency to mold information we recall is the way our brains fit facts into established mental frameworks. We tend to remember news that accords with our worldview, and discount statements that contradict it.

In another Stanford study, 48 students, half of whom said they favored capital punishment and half of whom said they opposed it, were presented with two pieces of evidence, one supporting and one contradicting the claim that capital punishment deters crime. Both groups were more convinced by the evidence that supported their initial position.

Psychologists have suggested that legends propagate by striking an emotional chord. In the same way, ideas can spread by emotional selection, rather than by their factual merits, encouraging the persistence of falsehoods about Coke - or about a presidential candidate.

Journalists and campaign workers may think they are acting to counter misinformation by pointing out that it is not true. But by repeating a false rumor, they may inadvertently make it stronger. In its concerted effort to "stop the smears," the Obama campaign may want to keep this in mind. Rather than emphasize that Obama is not a Muslim, for instance, it may be more effective to stress that he embraced Christianity as a young man.

Consumers of news, for their part, are prone to selectively accept and remember statements that reinforce beliefs they already hold. In a replication of the study of students' impressions of evidence about the death penalty, researchers found that even when subjects were given a specific instruction to be objective, they were still inclined to reject evidence that disagreed with their beliefs.

In the same study, however, when subjects were asked to imagine their reaction if the evidence had pointed to the opposite conclusion, they were more open-minded to information that contradicted their beliefs. Apparently, it pays for consumers of controversial news to take a moment and consider that the opposite interpretation may be true.

In 1919, Justice Oliver Wendell Holmes of the Supreme Court wrote that "the best test of truth is the power of the thought to get itself accepted in the competition of the market." Holmes erroneously assumed that ideas are more likely to spread if they are honest. Our brains do not naturally obey this admirable dictum, but by better understanding the mechanisms of memory perhaps we can move closer to Holmes' ideal.

Sam Wang, an associate professor of molecular biology and neuroscience at Princeton, and Sandra Aamodt, a former editor in chief of Nature Neuroscience, are the authors of "Welcome to Your Brain: Why You Lose Your Car Keys but Never Forget How to Drive and Other Puzzles of Everyday Life."

Original here

Exciting - and green - ways to get around

The Kero electric scooter is a popular choice.

Whether you're aiming to reduce your carbon footprint, save some money on petrol or just beat the traffic blues, there are some cheap, green and exciting ways of getting around that can replace your motor car.

Most journeys are only a few kilometres long and often with no passengers, so it makes sense to look beyond the car as the smartest way to cross the city. Of course there's the bicycle, or even public transport, but other options are worth considering.

ELECTRIC SKATEBOARD

Your skateboarding days may be long gone but these are becoming a viable option for getting from A to B then C.

They can reach up to 26km/h, a decent cycling pace, and the average battery life lasts for about 22km.

If you combine a skateboard with some public transport you have a low-cost, carbon-friendly way of getting around, not to mention convenient.

Some models even come with ABS braking and a special sensor to engage the brakes if the rider leaves the board.

Control is by a foot pedal or a hand-held remote control. Several models are powerful enough to get up steep hills. Prices range from $500 to $900 and off-road wheels are available if you want to leave the pavement.

ELECTRIC SCOOTER

Several companies are importing electric scooters for sale in New Zealand. The Kero is a popular brand and, depending on the model, you can get up to 90km on one charge (less if there are lots of hills or if you are carrying a passenger). Most models can be operated by holding a car licence and are similar to petrol- powered scooters. But you will need to get in the habit of charging it each night. Electric vehicles are quiet so you will need to be aware of pedestrians stepping out without looking.

ELECTRIC CAR

The electric car became established in California during the late 1990s in response to legislation requiring car manufacturers to produce alternative-fuelled cars. The customers loved them but when the law was relaxed, the car companies recalled the vehicles and despite many protests sent them to the crusher.

There are not yet any commercially available electric cars in New Zealand but that hasn't stopped several ingenious Kiwis making their own. One such enterprising motorist lives in New Plymouth. He has successfully converted an old Mitsubishi Tredia to run on electricity. It is totally road-legal and he has done the work himself on a tight budget.

If you'd like something a little more stylish than a Tredia, then a Tesla will be hard to beat. Available only in the United States or Europe, this electric car rockets to 100km/h in just 3.9 seconds. It runs for 1.5c a km and has a range of 350km per charge. Lotus Cars is assembling the Tesla Roadster under contract to Tesla Motors, so although it is an American car it is being assembled in the UK.

With Jay Leno, George Clooney and Arnold Schwarzenegger all reportedly on the waiting list, you'll be buying in some illustrious company. The 2008 production is sold out with a waiting list of 12 months. Priced at around $200,000, the Tesla has overcome all the negatives of earlier electric cars by creating a high-performance vehicle with a decent range between battery charging. Tesla has plans for lower-priced family vehicles.

ELECTRICITY SOURCE

With so many transport options powered by electricity, the question arises: how green is an electric-powered vehicle? Although it has no emissions you do have to be careful about the electricity source. If your power company is sourcing its electricity from a coal-fired power station then your travels will still be leaving a carbon footprint. Meridian Energy is carbon-neutral so would be a logical choice for supplying your electricity, as most of its electricity is hydro.

Or you could go one step further and generate your own electricity by installing photovoltaic solar cells on your roof. Unfortunately the capital cost of this means you will pay a lot more for your electricity than you do now but it would be good to know your transport is self-sufficient and very green. As electricity prices climb and new technologies are introduced this will become more viable.

BIODIESEL VEHICLES

Local company Environfuel is collecting waste cooking oils from restaurants and producing biodiesel for use in vehicles. Most diesel vehicles can be converted to run on biodiesel, at a cost of around $3000. You will also need a storage tank at home with the non-toxic/non-flammable fuel being delivered to you, 50 to 2000 litres at a time. Surely having your own fuel supply at home is just about worth it on its own. No more queuing at petrol stations or buying two chocolate bars for $3. Their biodiesel is selling for 89c a litre plus GST and if you are out of town your vehicle will still run on normal diesel, so range is not an issue.

If you are looking for an alternative fuel source but don't want it to be your legs you might consider something electric-powered for around town and perhaps a biodiesel vehicle for longer trips. Either way you'll be saving money and helping the planet.

* Richard Adams is a Wellington businessman in real estate and tourism marketing. This time last year he had three V8 cars and says he felt "a bit guilty" - so he got rid of the lot and is now considering ways to lower his carbon footprint.

Original here

Pentagon Fights EPA On Pollution Cleanup

By Lyndsey Layton

Washington Post Staff Writer

The Defense Department, the nation's biggest polluter, is resisting orders from the Environmental Protection Agency to clean up Fort Meade and two other military bases where the EPA says dumped chemicals pose "imminent and substantial" dangers to public health and the environment.

The Pentagon has also declined to sign agreements required by law that cover 12 other military sites on the Superfund list of the most polluted places in the country. The contracts would spell out a remediation plan, set schedules, and allow the EPA to oversee the work and assess penalties if milestones are missed.

The actions are part of a standoff between the Pentagon and environmental regulators that has been building during the Bush administration, leaving the EPA in a legal limbo as it addresses growing concerns about contaminants on military bases that are seeping into drinking water aquifers and soil.

Under executive branch policy, the EPA will not sue the Pentagon, as it would a private polluter. Although the law gives final say to EPA Administrator Stephen L. Johnson in cleanup disputes with other federal agencies, the Pentagon refuses to recognize that provision. Military officials wrote to the Justice Department last month to challenge EPA's authority to issue the orders and asked the Office of Management and Budget to intervene.

Experts in environmental law said the Pentagon's stand is unprecedented.

"This is stunning," said Rena Steinzor, who helped write the Superfund laws as a congressional staffer and now teaches at the University of Maryland Law School and is president of the nonprofit Center for Progressive Reform. "The idea that they would refuse to sign a final order -- that is the height of amazing nerve."

Pentagon officials say they are voluntarily cleaning up the three sites named in the EPA's "final orders" -- Fort Meade in Maryland, Tyndall Air Force Base in Florida and McGuire Air Force Base in New Jersey.

Fort Meade borders residential areas in fast-growing Anne Arundel County; Tyndall and McGuire are in less-populated regions. At all three sites, the military has released toxic chemicals -- some known to cause cancer and other serious health problems -- into the soil and groundwater.

But the EPA has been dissatisfied with the extent and progress of the Pentagon's voluntary efforts.

"Final orders" are the EPA's most potent enforcement tool. If a polluter does not comply, the agency usually can go to court to force compliance and impose fines up to $28,000 a day for each violation.

Cleanup agreements drafted by the EPA for the 12 other sites contain "extensive provisions" that the Pentagon finds unacceptable, officials said.

Congress established the Superfund program in 1980 to clean up the country's most contaminated places, and of the 1,255 sites on the list the Pentagon owns 129 -- the most of any entity. Other federal agencies with properties on the list include NASA and the Energy Department, but they have signed EPA cleanup agreements without protest.

The law was amended in 1986 to stipulate that polluting government agencies should be treated the same as any private entity. During the 2000 presidential campaign, George W. Bush pledged to direct all federal facilities to comply with environmental laws and "make them accountable."

In dealing with cleanup efforts, some military branches have been more cooperative than others. The Navy has signed cleanup agreements for all of its Superfund sites, whereas the Air Force has not signed one in 14 years.

But Superfund sites are only one aspect of the Pentagon's environmental problems. It has about 25,000 contaminated properties in all 50 states, and it will cost billions and take decades to clean them up. The Pentagon has a tremendous financial stake in not only how the sites are cleaned but also in which chemicals the government characterizes as toxic.

Rep. John D. Dingell (D-Mich.), chairman of the House Energy and Commerce Committee, is investigating the Pentagon's compliance with environmental regulation. He said it is evading the law through political maneuvers.

"I find it troubling, not only that the Department of Defense is in flagrant violation of final orders issued by the EPA, but that DOD is now attempting to circumvent the law and Congress' intent by calling on the Department of Justice and the Office of Management and the Budget to intervene," he said in a statement. "The EPA is the expert agency charged by Congress with enforcing our environmental laws, and the Administration needs to allow them to do their job to protect the public health and safety."

EPA spokeswoman Roxanne Smith said final orders were issued because the agency is worried about drinking water and soil contamination at Fort Meade, Tyndall and McGuire. "Under DOD's management, some of these sites have languished for years, with limited or no cleanup underway," she said.

Other examples of Pentagon resistance to the EPA include its successful effort this year to get greater influence in the process the agency uses to analyze the risks of industrial chemicals. Congressional Democrats, environmental groups and the Government Accountability Office have criticized the change.

The Pentagon has also fought EPA efforts to set new pollution standards on two toxic chemicals widely found on military sites: perchlorate, found in propellant for rockets and missiles, and trichloroethylene (TCE), a degreaser for metal parts.

TCE is the most widespread water contaminant in the country, seeping into aquifers across California, New York, Texas, Florida and elsewhere.

More than 1,000 military sites are contaminated with TCE.

In the late 1990s, EPA scientists found TCE to be much more toxic than earlier believed. In 2001, the EPA prepared tougher new drinking-water standards for TCE to limit human exposure, but the Pentagon challenged those standards and took its case to the White House. The process ground to a halt; seven years later, the EPA still has not issued new TCE limits.

Since Bush took office, one military site has been added to the Superfund list -- the Navy bombing range at Vieques Island, off Puerto Rico.

The site was added after the Puerto Rican governor exercised a federal statute to force its placement on the list.

Maryland has been pushing the EPA to add Fort Detrick in Frederick County to the Superfund list. This month, the state sent a forceful letter to the EPA, suggesting it would follow Puerto Rico's strategy. On Thursday, the EPA informed Maryland that in September it will recommend Fort Detrick be added.

Shari T. Wilson, Maryland's secretary of the environment, said the state needs the Superfund designation because of the Army's erratic efforts to clean up Fort Detrick, which for decades served as the service's center for development of chemical and biological weapons. She said the state wants an independent agency that is focused on public health to oversee the effort and hold the Pentagon accountable.

In 1992, the state found chemical contamination in private wells just outside Fort Detrick. Under a voluntary agreement with the state, the Army removed chemical-soaked earth and rusting drums filled with toxins, set up monitoring wells and connected nearby residents to the city water supply.

Two years later, TCE was detected in a spring outside the base -- the first time it was noticed beyond the facility's boundaries. State officials say that the presence of TCE in the aquifer is a serious concern but that they do not think the contamination poses an immediate health threat.

For nearly 10 years, Maryland has asked the Pentagon to analyze the extent and spread of groundwater contamination, a study that will happen as a matter of course if it is added to the Superfund list.

"It's frustrating," Wilson said. "We need to move ahead and take the steps necessary to ensure for the public the groundwater is protected."

Original here

Japan Says We are Witnessing the Death of the International Whaling Commission

Written by Levi Novey

On Friday, the International Whaling Commission’s annual meeting came to a close with a whimper. This year’s gathering was held in Chile, and the meeting’s chairperson, United States delegate William Hogarth, made a gutsy and stupid decision. Hogarth wanted to avoid confrontations at this year’s meeting, with the hope of creating good will among countries. He pontificated that this good will could be used to find solutions in the future (not now). Translation: he pleaded for member countries not to vote on or discuss important issues that concern whales. Based on what happened (or more accurately, did not happen), the meeting was very unsuccessful.

Why Was There Tension at This Year’s Meeting?

Japan and other countries like Norway and Iceland are currently killing whales, despite dangerously low numbers for certain species. This has triggered significant disapproval from countries like Australia, who are vehemently opposed to whaling. Japan claims that they kill approximately 1,000 whales each year for scientific purposes. Many countries and environmentalists view this explanation as a blatant lie. They think Japan simply wants to kill whales so that they can sell and eat the meat (Iceland and Norway just want to sell it to Japan it seems). Angered by international criticism of their whaling practices, Japan has threatened to withdraw as a member nation of the International Whaling Commission, barring the condition that countries agree to allow sustainable whaling of abundant whale species.

What Were the Outcomes of This Year’s Meeting?

After this week’s meeting, it seems hard to think of there being much success to talk about. Things got off to a good start as Chile announced that they were initiating a permanent ban on whaling. A proposal by several Latin American countries to create a South Atlantic Whale Sanctuary was unfortunately withdrawn at the urging of people like William Hogarth. The only other major events were

1. a vote that barely blocked Greenland from hunting 10 more humpback whales per year. 36 member nations voted against the proposal, and 29 voted for it.
2. the creation of sub-set of member nations to work on building consensus on contentious issues over the next year.

After the meeting, Reuters ran an article with the title: “Whales lose, Japan wins as whaling meeting ends.” The article includes various quotes of people involved in the meeting, and basically confirms this author’s suspicion that the meeting was largely a bust. AFP quoted William Hogarth as saying he was “very pleased” with the outcome of the meeting. His effort to build consensus at the meeting by doing nothing was, in fact, an incredibly stupid strategy. Japan’s representative was quoted after the meeting as saying “the world is witnessing the death of an international organization.” If Japan is not going to get on board the Hogarth Good Will Express, then what’s the point?

I personally am not opposed to finding a sustainable whaling solution that seeks some middle ground. Perhaps there are some species of whales that are abundant enough to allow for a minimal, token amount of whaling. Having a meeting where nothing of importance is discussed though, in my mind is just plain stupid. Hopefully William Hogarth has lost his chance at chairing any more of the International Whaling Commission’s meetings.

Next year’s International Whaling Commission meeting will be held in Portugal, and hopefully Portugal will announce a permanent ban on Hogarth chairing any more meetings.

Original here

8 Ways to Green Your Garden

By Trey Granger

Summer is a great opportunity to spend time in the garden. Sunny days provide nice weather and extra daylight. School is out so you've got extra potential workers. The ground is fertile from springtime rain.

Your garden may seem very green by definition. But here's a few ways to reduce the impact your garden has on the environment as a whole.

1. Plant Within Your Environment

In a perfect world, you could grow cactus in a tundra climate and a lawn of Bermuda grass in the desert. Guess what? Plants don't work that way. Before you start growing something, do some research to see what it needs to survive in your area. Otherwise, you may end up using lots of water and other resources to have “something different” in your backyard.

2. Water in the Mornings

Like it or not, some of the water meant for your plants will evaporate before it reaches the soil. This is compounded on a hot day. Watering in (or setting your sprinkler timer for) the morning can save 50 gallons of water a week.

Other good water saving tips:

• Sweep away leaves with a broom/rake instead of a hose

• Check your sprinkler heads periodically for leaks

• Install a control nozzle on your hose

3. Compost

Soil and fertilizer are expensive, so why not make your own? Take organic waste from your kitchen (fruit/vegetable peels, egg shells) and mix with yard waste (leaves, flowers) and water. The result is compost, which is rich in nutrients and will help your plants grow.

4. Find Second-Hand Supplies

You may not want to buy underwear used, but how about a shovel or wheelbarrow? Look for these items at garage sales and thrift shops before buying a new one. If you do buy new, ask if the products come with a warranty so they will last you a long time.

5. Reuse Your Pots

Plants die, but pots rarely do. Save the pot and soil if one of your plants expires. You can even create your own pots by drilling a hole in old butter containers or flipping over a drum. If a pot breaks, you can usually glue it back together with no loss of quality.

6. Grass-cycle

One of the least fun tasks of mowing the lawn is picking up the scraps. It's actually beneficial to your garden to leave them there. The grass clippings will provide nutrients to the remaining yard as they decompose. Plus, you'll have one less plastic bag to dispose of.

7. Recycle Yard Waste

If you decide that composting isn't for you and you enjoy picking up grass clippings, definitely recycle your yard waste. This material takes longer to decompose in a landfill when buried under a pile of plastic. Plus, if your local community accepts yard waste you may be able to exchange it for compost to use in your garden. Recycle yard waste using Earth 911.

8. Use Natural Pest Management

Pests can wreak havoc on your garden. But you don't need pesticides to keep them away. Pesticides harm all kinds of living things, including humans. Plus, they can be easily transferred into natural bodies of water and our water treatment systems are not designed to remove pesticides.

You can plant natural pest repellants like chrysanthemums and marigolds nearby. Learn other ways to practice integrated pest management.

Original here

Australian crocs hit by cane toad 'wave of death'

A last supper? Freshwater crocodiles have been seen eating the toxic cane toads (Image: Mike Letnic/ University of Sydney)Enlarge

Dead "freshies" are now often seen in and around the Victoria River – this was once an unusual sight (image: Mike Letnic/ University of Sydney)Enlarge

Rachel Nowak

Pit a cane toad against a freshwater crocodile and who wins? Although the croc eats the oversized amphibian, it seems the toad has the final laugh.

Dead freshwater crocodiles in Australia's Northern Territory were once a rare sight. But since 2005, locals have witnessed mass die-offs. Researchers now say the toxic and invasive cane toad (Bufo marinus) is to blame.

Two surveys, in 2005 and 2007, suggested that the mass croc deaths have progressively moved inland from the mouth of Victoria River, at a pace that matches that of the cane toad invasion. The toads secrete a milky-white toxin which is lethal to many predators from glands behind their eyes and on their backs.

Mike Letnic of the University of Sydney and his team say a massive 77% of some populations of freshwater crocodiles – or "freshies" – have died since 2005.

The numbers are particularly worrying, says Letnic, because removing top predators like freshwater crocodiles (Crocodylus johnstoni) can boost the number of their prey and trigger a cascade of ecosystem changes that are difficult to predict.

Pest out of control

Cane toads were introduced to Queensland in northeast Australia in 1935 to combat the cane beetle, a sugar cane pest, and have been steadily marching westward across the continent since.

They are now considered invasive pests in their own right: they have decimated populations of Australian monitor lizards and certain species of snakes.

To try and understand the damage the toads are inflicting, Letnic and his colleagues surveyed crocodiles in four regions of the Victoria River in the Northern Territory.

Crocodile sightings in the Victoria River Gorge region, where the invasion began, dropped from 156 to 49 between 2005 and 2007. The toads moved upriver from the gorge, reaching the Longreach Lagoon region in 2007. There, sightings dropped by 15% compared to 2005.

"We expected this. We first heard reports of dead freshies from helicopter pilots flying over rivers in the Gulf of Carpentaria [east of Victoria River] where cane toad had invaded," says Grahame Webb, director of Wildlife Management International in Darwin.

"It was a disaster waiting to happen. If it had been whales or some species with big brown eyes every one would have been up in arms," he adds.

Wave of death

Proving a causal link between cane toads and crocodile deaths is tricky, in part because crocs rapidly digest amphibians, so traces are rarely found. But Letnic says the "wave of death" has moved upstream with the toads, strongly suggesting the toads are the cause of the dropping crocodile numbers.

Letnic's team is continuing the surveys. They say the freshies and cane toads are often seen in close proximity to each other. This is likely to be all the more true in dryer regions like the semi-arid upper reaches of the Victoria River where the two species are forced to share water holes, says Letnic.

If true, cane toads could pose an even greater threat to native species as they move south into the dry interior of Australia and the need for water brings them into close proximity.

The researchers say in the long term, the high death rate may naturally select for crocodiles that have a higher tolerance to the toad toxin. This has been seen to happen in some blacksnake populations that have also been hit hard by the cane toads.

In the meantime, however, the toxin appears more lethal to younger crocs, suggesting that the reproductive rate of the populations could take a big plunge.

Original here

Personal, green airplanes set to take off

By Elsa Wenzel, CNET news.com

1 | 2 | 3 | Next >

The idea of personal planes may conjure up dark visions of “Blade Runner,” but the first batch of two-seater aircraft to fly on electricity rather than fossil fuels could reach more than a dozen buyers by year's end.

And if some fans of experimental air travel have their way, that's a step closer to a gridlock-free future when relatively ordinary folks will hop to work in small, carbon-neutral planes.

A cozy crowd of several dozen engineers, venture capitalists, and members of clean-tech companies plotted the potential at the Electric Aircraft Symposium held in April in San Francisco, sponsored by Foundation Capital and held by the CAFE Foundation, a nonprofit aiming to advance personal air travel. CAFE stands for Comparative Aircraft Flight Efficiency.

The meeting included Ivo Boscarol, CEO of Pipistrel, which by the end of this year is set to deliver the first commercially produced, two-passenger electric aircraft to customers. The Slovenian company's Taurus Electro can climb to 6,000 feet after taking off on a 30-kilowatt motor. Recharging the glider's lithium-polymer battery is meant to take about as long as powering a cell phone. Depending upon the weather and skills of the pilot, the glider can travel 1,000 miles in a day.

"I'm sure that electric power everywhere will be the substitute for internal combustion fuel engines," Boscarol said. "First, you must develop (an) aircraft that needs so little power that electricity is efficient."

The glider weighs little more than 700 pounds and costs $133,000, only about one-third more than the electric Tesla Roadster, a hot toy for billionaires.

Pipistrel's customers include Formula One driver Pedro de la Rosa. But even Google co-founder Larry Page, who attended the forum, might have to wait to purchase the electric Taurus if he were interested. It is in the final stages of test flights and will be manufactured in a limited run this year. And in the United States, the Federal Aviation Administration would prevent people from flying the glider under the same rules as light sport aircraft.

However, FAA rules could change, possibly within the next year. The Experimental Aircraft Association announced recently that it has filed a request for the FAA to change how it classifies electric aircraft. If the group's petition succeeds, the U.S. market could open up for other electric craft on the horizon.

"Changing the way we move through the environment is critical to this planet," Experimental Aircraft Association representative Craig Willan told the crowd. "This is the first step to ensuring not only government compliance but also assistance."

The FAA usually takes about six months to make such decisions, according to agency inspector Matt DeSeelhorst.

Sustainable air travel
Aircraft emissions, including carbon dioxide, nitrogen oxides, and methane, account for up to 3 percent of the world's greenhouse gas pollution, according to the Intergovernmental Panel on Climate Change. Although the bulk of that comes from hulking commercial jets, light aircraft continue to use leaded fuel, which the government moved to phase out in passenger cars 35 years ago.

Making air travel more sustainable will be tricky in the United States, where the number of aerospace engineering graduates has plummeted by 57 percent since 1990, said Brien Seeley, CAFE Foundation president.

By contrast, support for light aircraft development is strong in the European Union, which contributed about 20 percent of the $2.3 million that Pipistrel spent creating the Taurus Electro, according to Boscarol.

The U.S. Defense Advanced Research Projects Agency has supported the development of lightweight, stealth aircraft, but its innovations aren't necessarily reaching the civilian level soon. The federal government yanked its support more than two years ago for NASA's personal aircraft research group.

However, NASA is spending $2 million over five years on contests held by the CAFE Foundation and backed by Boeing Phantom Works. Last August, the inaugural NASA Personal Air Vehicle Centennial Challenge handed out $250,000 in prizes rewarding the efficiency and noise reduction of personal air vehicles. The top place went to the owner of a Pipistrel Virus motorglider.

This year's contest will include its first Green Prize of $50,000 for a craft that achieves at least 100 miles per hour and the equivalent of 100 miles per gallon. Renamed the General Aviation Technology Challenge, the contest will dole out a total of $300,000.

Supporters of such competitions hope they can convince people that air travel could become the greenest form of transportation.

"It will change society, the way we work, the way we live, the way cities grow," said Richard Jones, a technical fellow at Boeing Phantom Works.

The research group is designing a plane-car hybrid to travel up to 300 miles at a time. Jones believes that by 2030, precision navigation systems could make it easier to pilot a compact plane than to drive a car.

"People will probably be reading a newspaper rather than flying the vehicles," he said.

The trick is equipping aircraft with a brain as smart as a seagull's, said NASA aerospace engineer Mark Moore, who headed NASA's now-shuttered personal aircraft research group. And responsive tactile controls, such as steering mechanisms that resist a hand's wrong move, can prevent human error.

Coming closer to that goal is the Garmin G1000 Synthetic Vision System, noted several attendees. Released in April, it enables pilots to view topographic details even in foggy conditions within a Google Earth-like interface.

Hertz Rent-A-Plane?
CAFE Foundation's Seeley displayed a mock-up interface that would draw a virtual pathway in the sky to keep a pilot on track.

"This is how we're gonna get eventually to Hertz Rent-A-Plane," he said.

However, developing batteries and engines light enough for small commuter aircraft remains tricky. Pipistrel is working with the University of Stuttgart in Germany to design hydrogen-fuel-cell-powered aircraft, as is Lange Aviation with the German Aerospace Centre, but results remain distant.

Others are working to improve upon readily available lithium-ion batteries. Yi Cui, a Stanford assistant professor of engineering, is exploring the use of nanowires as battery electrodes to pack more power into a smaller package. Unpublished results from lab tests have been promising, said Cui, who hopes to commercialize the technology within the next five years.

The secretive EEstor, also working to improve energy density in batteries, presented at last year's Electric Aircraft Symposium. In January, Lockheed Martin announced plans to buy EEstor's ultracapacitors, which reportedly weigh one-tenth less than lead-acid batteries but hold 10 times more energy.

Self-funded start-up Windward Performance of Bend, Ore., is working to build a light aircraft that would fly on a battery at 15 kilowatts per hour for about $1.50 per charge.

"This would be a completely off-the-grid and off-oil passenger plane," said creator Greg Cole, who hopes to raise $2 million. His redesign of the Sparrowhawk sailplane is known as the first with wings and fuselage made of all carbon composite materials.

Hybrid airplanes that blend electric and biofuel engines could be the bridge to off-grid, oil-free air travel, according to some proponents of personal, "green" air travel.

Engineer Greg Stevenson displayed a two-cycle diesel engine that weighs 18 pounds and can run on biofuels. "It's as omnivorous as it's gonna get," he said.

At a fraction of the 200-pound weight typical of commercial diesel engines, that type of innovation might help pave the way for powering hybrid, lightweight biofuel/electric aircraft.

Original here