University of Oulu (Finland) Department of Geosciences

The project will be part of a major ongoing geoscience consortium “Evolution of the 3D structure of the Svecofennian bedrock.” Consortium members are the Universities of Helsinki, Turku, Oulu, Åbo Akademi and Geological Survey of Finland and Posiva Oy. The project is financed by the Finnish Academy. The subproject of the University of Oulu is focusing on the development and evolution of the Palaeoproterozoic Raahe-Ladoga transform boundary zone, which is a crustal scale ductile shear zone probably reactivated several times during tectonic evolution of the shield.

For more information: http://www.oulu.fi/english/ or pekka.tuisku@oulu.fi. Click here for details.

Researchers find clues about changing climate in redwoods’ old rings

In a small room tucked away in an obscure corner of Southern Oregon University’s Science Building, Kenneth Olejar positions himself on a pillow atop a gigantic, 6-foot-wide slab of redwood, peering intently through a microscope at the tree rings underneath him.

Above:  Lin Roden studies the rings in a slab of redwood Friday in the Late Holocene Climate Change Facility at Southern Oregon University’s Science Building. The rings are helping her, her husband, John Roden, and students map out the past 1,000 years of climate change history in redwood country. Julia Moore / Daily Tidings.

The microscope is attached to an electric micrometer, which in turn is hooked up to a computer in the corner of the room.

The micrometer allows Olejar to precisely measure the size of each tree ring, telling him how much moisture the tree got that year, and during which part of the year the tree got it.

Olejar spends hours at a time down here, meticulously measuring each tree ring, and marking promising years for a more in-depth analysis. He works in short sleeves, as the room is kept warm to prevent the redwood slabs from soaking up moisture and expanding. Some of the younger slabs lying around are only a few hundred years old, while others are more than 1,900, such as the one casually propped up against the cabinet in the outer office.

Olejar is the lab manager for the Late Holocene Climate Change Facility, a big name for a small laboratory housed in a nondescript room in the depths of the Science Building.

Using these tree rings, Olejar is helping John Roden, an SOU biology professor, and Lin Roden, lab manager for SOU’s Stable Isotope Lab and John’s wife, map out the past 1,000 years of climate change history in redwood country.

“The basic idea for this, and the reason it was funded, is because of a thing called climate variability,” said John Roden. “The idea is that we need to know how climates have changed in the past to better understand how climates might change in the future.”

Roden has been studying climate change in the Pacific Northwest for years, analyzing the stable isotopes of carbon and oxygen in tree rings to determine the type and amount of moisture the tree absorbed that year. The stable isotopes of carbon and oxygen are naturally occurring elements and typically analyzed by climatologists to determine temperature and precipitation over the years.

“The isotopes in the tree ring are telling us about the environment of the tree when it grew,” said Roden. “If climate change features change the environment and the ratio of isotopes in the tree rings, then the tree rings give us a historic record of those climate features.”

Roden was awarded a National Science Foundation grant in 2003 to conduct a 50-year climate change study, comparing the results of his tree ring analysis to the weather records of the Arcata Airport in Arcata, Calif., and other weather stations scattered throughout the Pacific Northwest. His results correlated closely with the weather station records, so the NSF awarded him two more grants, totalling about $1.1 million, to continue his research, this time going back 1,000 years.

Roden said that while tree ring studies had been conducted in the past, none of them have gone this far back, and very few have analyzed the stable isotopes in the rings. He also explained that of all the long-term climate change studies conducted, none of them are as time-specific as studies using tree rings, because each ring represents one year.

In the Arcata study, Roden had to collaborate with the University of California at Berkeley, as SOU didn’t have a stable isotope mass spectrometer, a specialized piece of research equipment that analyzes the stable isotopes in the tree rings. One of the two recent NSF grants changed that, however, and now SOU is the proud owner of a quarter-million-dollar, mini-fridge-sized, tabletop stable isotope mass spectrometer.

There are several different steps the tree ring must go through before it can be run through the mass spectrometer, however.

First, a sample is milled from a specific tree ring. The sample is then run through a chemical process that burns off all the resin, wax and wood sap, leaving pure cellulose — carbon, hydrogen and oxygen. The cellulose is weighed and loaded into a furnace, which heats it up to 1,450 degrees Celsius, evaporating it.

The gases left over from the cellulose then are passed into the mass spectrometer. Once in the machine, it is run through an electron source, which ionizes the gases. The gases are then run through a strong magnetic field and land on a sensor array. The data are then sent to a computer, where Lin Roden compiles them and sends them off to John Roden to be analyzed.

“(The process) is kind of labor intensive,” said Lin Roden, although she explained that the stable isotope lab also was running experiments for other members of the department.

Back in the Late Holocene Climate Change Facility, Olejar still is hard at work, measuring the tree rings. There are hundreds of them spread out beneath him, collectively recording several hundred years of climate history.

“I’ve always worked in research labs before, so I don’t know, this seems normal to me,” he said, commenting on the monotony of the research. “For me, it’s no different than being a chemist at a pharmaceutical company and going into the lab with 1,000 pipets.”

– by Nils Holst/Souther Oregon University: holstn@sou.edu.

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In 1930, Ernest Lawrence observed a curious aspect of his new atom-smashing accelerator, the cyclotron: The decaying isotopes it produced continued to emit gamma rays long after emerging from the collisions that produced them. When Ernest told his brother John, a physician, about the radiating isotopes, the field of nuclear medicine was born. In the postwar years, the technology burgeoned into a widely recognized cancer-fighting tool.

Today, tens of millions of patients each year are diagnosed and treated with accelerator-based radioisotopes. While radioisotopes with long half-lives are often formed in nuclear reactors, more than 300 cyclotrons across the United States produce short-lived isotopes for hospitals.

The cyclotrons work by spiraling charged particles such as protons around a magnet, outward from the center. To produce the isotope fluorine-18, for example, when the particles reach an energy of about 10 million to 15 million electronvolts they slam into a water target enriched with the oxygen-18 isotope. The resulting fluorine-18 isotope is chemically separated and combined with a sugary glucose compound that is ready for delivery to the hospital or clinic. The process takes as little as a few minutes.

With a 110-minute half-life, 18F has wide use in diagnostic imaging. The 18F glucose compound is an energy source for cells in the body. Administered intravenously, the compound collects in areas of high metabolic activity, such as cancerous tumors. Then a positron emission tomography (PET) scan of the emitted gamma rays provides detailed three-dimensional images of the cancer.

“18F metabolic imaging has had a major impact on the process of determining the cancer stage and in evaluation of the response to therapy,” said Jack Correia, director of the Cyclotron Laboratory at Massachusetts General Hospital. “Nowadays in the United States, Western Europe, Japan or Australia an individual with a preliminary diagnosis of a malignancy would wind up having an 18F scan.”

Some radiotherapy treatments implant metallic radioisotope “seeds” with relatively long half-lives directly into a tumor, where the emitted gamma rays destroy the cancer cells.

Due to its extra-long half-life of 66 hours and its ability to produce a shorter-lived daughter, the most popular isotope for diagnostic imaging is molybdenum-99, or Moly-99 for short. Produced abroad by only three nuclear reactors devoted to radioisotope production, Moly-99 is involved in more than 50,000 procedures worldwide each day. Physicists hope to develop accelerators in the United States to reliably mass-produce Moly-99 and other radioisotopes.

– by Brad Hooker/SymmetryMagazine.org

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Ireland’s links with the Roman empire are being investigated in a new archaeological project in which science plays a large part

FIRST CENTURY AD. The Roman General Agricola reportedly says he can take and hold Ireland with a single legion. Some archaeologists have claimed the Romans did campaign in Ireland, but most see no evidence for an invasion. Imperial Rome and this island on its far western perimeter did share interesting links, however.

The Discovery Programme, a Dublin-based public institution for advanced research in archaeology, is to investigate Ireland’s interactions with the empire and with Roman Britain, aiming to fill gaps in the story of the Irish iron age, the first 500 years after the birth of Christ.

The project, Late Iron Age and Roman Ireland (Liari), could uncover a surprising role for Roman culture, predicts Dr Jacqueline Cahill Wilson, project leader. It offers “a new narrative for this formative period of early Irish history”.

Science is going to drive the project, and the interpretation presented by the researchers will be based on science as much as the archaeology, Cahill Wilson explains.

Roman artifacts including coins, glass beads and brooches turn up in many Irish counties, especially in the east.

Cahill Wilson investigated human remains from iron age burial sites in Meath for her doctoral research at the University of Bristol. She learned much about these people by using strontium and isotope analysis and carbon dating.

Remarkably, this allowed her [to] say where they most likely spent their childhood. One burial site on a low ridge overlooking the sea in Bettystown, Co Meath, was dated to the 5th/6th century AD using radiocarbon dating. Most of the people were newcomers to the area, Cahill Wilson concluded.

The clue was in their teeth. Enamel, one of the toughest substances in our body, completely mineralises around the age of 12 and its composition remains unaltered to the grave and beyond. It is “a snapshot of where you lived up to the age of 12”, Wilson explains.

The element strontium (Sr), which is in everything we eat and drink, exists in a number of chemical forms, or isotopes. The ratio of two of these isotopes (87Sr and 86Sr) varies, shifting with the underlying geology, and this too can indicate where the owner of the tooth grew up.

Similarly, the ratio of oxygen isotopes varies with factors such as latitude, topography and hydrological conditions.

“Enough comparative data is available now that we can start to plot and map the ratios to see where people are likely to be from,” Cahill Wilson explains. Paired analysis of strontium and oxygen in tooth enamel from a burial in Bettystown revealed that one interred individual grew up in North Africa.

Eamonn Kelly, keeper of Irish Antiquities at the National Museum of Ireland, distinctly remembers the Bettystown excavation, which he directed in the 1970s. “One particular burial stood out as being very unusual,” he says. The body lay in a crouched position and seemed to have been treated in a different manner to the rest of the burials. This male could have been a slave, but Kelly thinks he was most likely a trader, possibly from the Roman world.

Roman material has been found at Tara and Newgrange, and Roman pottery has been dredged from the River Boyne. A large coastal promontory fort in north Dublin also turned up Roman objects, and Kilkenny hosts a Roman burial site.

Kelly believes the Romans never invaded because the countryside was unsuited to their villa system: the economic cost-benefits failed to stack up, he says. “These guys could get what they wanted without being physically present. I think what they were interested in from Ireland was agricultural produce, probably butter, cattle and cattle hide, as well as slaves and mercenaries.”

The Liari project will deploy advanced survey techniques in Dublin, Westmeath and Kilkenny to seek evidence for Roman sites. Robert Shaw, senior surveyor for the programme, describes aerial laser scanning, or Lidar, as one of the most important developments in archaeology over the last 10 years.

This models the landscape surface in exquisite detail. The ground-based techniques rely on measurements of magnetic and electrical resistance anomalies of the earth, so no destructive digging is required.

Surveys are not expected to uncover the Roman’s distinctive linear roads or their large rectangular forts, but what did it mean to be “Roman” in Ireland?

The warring centurians and toga-wearing politicians made popular in film comprised less than two per cent of Roman Britain.

“The rest of the people engaged with the new Roman administration in a variety of ways,” says Cahill Wilson, and “there were different ways to be a Roman within the provinces”.

The project will use the latest scientific methods, such as geochemistry, to explore population migration, X-ray fluorescence and isotope analysis to trace the origin of metals and minerals, and pollen analysis to resurrect past environments.

“We need to be a bit more systematic and scientific in terms of what we are doing,” says Cahill Wilson, but these tools are additions to traditional archaeology’s kit.

Kelly says it is not surprising Roman material turns up, especially on the coast facing Roman Britain. We know Niall of the Nine Hostages had a British mother, he says. “These guys were marrying women from the other side of the Irish Sea. There would have been dynastical alliances across the sea.

“Ireland was in immediate proximity to the world superpower,” he adds. “Ireland was becoming heavily influenced from the 1st century AD by Rome. The introduction of Christianity in the 5th century is just part of that process.

“We took on a great swathe of Roman cultural influence, including the Roman religion, and all without a Roman legion landing and telling us how to do our business.”

At the National Museum, Kildare Street, Dublin, visitors can see displays of imported Roman objects and the influence of the Roman world on the culture of pagan and early Christian Ireland in the Treasury exhibition. A second exhibition hosts objects from across the Roman world.

Bodies in the bog: uncovering the rituals of death

“WE HAVE A national anatomical collection second to none,” says Eamonn Kelly, Keeper of Irish Antiquities at the National Museum of Ireland. He is referring to the thousands of human remains held in a custom-built store.

These are hugely important to archaeological and medical research, but the meticulous archives on the excavations are also a treasure trove, says Kelly.

Remains still turn up. An Iron Age body found in a Laois bog last August is giving up its secrets under scientific scrutiny. The remains are in the process of being dated using radiocarbon methods and a forensic examination has been carried out to identify injuries. This bog body, believed to be a ritual sacrifice, underwent a CT scan out-of-hours in Tallaght Hospital last December. Museum staff will now be looking to see if the remains of a ritual meal are still present in the body.

Laureen Buckley is an experienced forensic archaeologist, often called to crime scenes. But she examines mostly prehistoric remains. “When they come into the lab, they are cleaned up and laid out on a table, similar to a post-mortem. Everything is laid out in its correct place and you go through it bone by bone.”

She can sex skeletons by examining the shape of the bones in the skull, the pelvis and ribs. “There are features of the skull, the supra-orbital ridges in the forehead and the mastoid process behind the ear. These are fairly well developed and pronounced in males, but softer and smaller in females.”

Aging can be done up to about 25 years, after which all bones are fully mature. Gauging age after that becomes more difficult, says Buckley.

Prehistoric can be distinguished from modern and medieval remains by looking at the teeth. A softer modern diet causes less wear on teeth.

Another novel way to identify a post-medieval, but not modern, individual is by notches on their teeth. These little semi-circles are the vestiges of hours spent smoking tobacco with a clay pipe. Tobacco was introduced in the 17th century and clay pipes went out of fashion by last century.

A new book to be published shortly will document more than 400 burial sites over a 70-year period by museum archaeologists – Breaking Ground, Finding Graves.

– by Anthony King/IrishTimes.com

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The Conservative government is testing the waters for the sale of Atomic Energy of Canada Ltd.’s nuclear research labs.

Ottawa is now seeking companies to “participate in, invest in and/or manage the laboratories.”

“The restructuring is considering how to reduce federal contributions to AECL, notably through enhanced cost-recovery for all services AECL provides to third parties, and/or through partnership or management opportunities as identified through this or other processes,” says a document posted on a website that advertises government contracts.

“Nuclear infrastructure is expensive and while some costs have been recovered by the government, there is still significant federal financial support.

“The restructuring needs to determine the activities of interest to those stakeholders willing to invest in AECL, which would enable enhanced sharing of both benefits and risks while strengthening accountability.”

The move comes after Ottawa sold the Crown corporation’s Candu nuclear reactor business to SNC-Lavalin in October for $15 million.

Since the sale of the reactor business, AECL has focused on its nuclear laboratories division, which has a staff of more than 3,000, mainly in Chalk River, Ont., and Pinawa, Man. The division manages nuclear waste, conducts research and produces medical isotopes.

The document notes AECL’s nuclear liabilities are estimated at about $5.4 billion. That includes decommissioning facilities and dealing with a wide variety of buried and stored waste. AECL is also contracted to manage radioactive waste for hospitals, universities and medical isotope producers.

The government pegs the cost of waste management and decommissioning at $325 million in the coming years.

“The government is seeking proposals and/or recommendations from respondents on how to manage these nuclear liabilities in the safest, most cost-effective and timely manner,” the document says.

“In particular, one of the options under consideration would be a private-sector contract for the management of legacy radioactive waste and decommissioning obligations, where incentives could be used to reduce this liability in the safest manner possible, while accelerating timelines, thus potentially reducing the overall financial burden on Canadian taxpayers.”

Natural Resources Canada bristled at the suggestion the government is trying to sell off AECL’s nuclear labs.

“The government is issuing a request for expression of interest … to understand potential opportunities for partnership models and the relevant experience and capabilities offered,” spokesman Paul Duchesne said in an email.

“The information gathered through this process will help inform the restructuring process, a critical step to further strengthen Canada’s nuclear industry while reducing taxpayers’ exposure to financial risks in this sector.”

Duchesne added the government does not expect private-sector interest in the purchase of the entire facility.

The Crown corporation has long been a headache for successive federal governments.

AECL has cost Canadian taxpayers billions of dollars and faced major cost overruns at key projects in recent years while struggling to find a buyer.

In May 2009, the Conservative government announced plans to spin off AECL’s commercial reactor business from its research division.

The announcement coincided with what turned into a lengthy shutdown of the company’s Chalk River research reactor, which caused a worldwide shortage of the medical isotopes used to detect cancer and heart ailments.

The National Research Universal reactor was down for 15 months. There were times when it looked like the half-century-old reactor might never return to service.

An earlier shutdown in late 2007 also strained the global isotope supply and ended only after Parliament voted to bypass the nuclear safety regulator’s closure order.

The Harper government plans to get Canada out of the medical isotope business. But the document posted Thursday says Ottawa will entertain proposals for isotope production under certain circumstances.

“Isotope production constitutes a major, non-research-based activity at the laboratories. As indicated in the government’s response to the report of the expert review panel on medical isotope production, the government does not intend to have the NRU produce medical isotopes beyond 2016,” the document says.

“The laboratories offer significant infrastructure and expertise in the medical isotope production field. Private-sector proposals for isotope production could be considered if the full costs (capital and operating), liabilities and risks were covered without any further public investment to support such activities.”

– CTV News

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For years, scientists and policy makers have been trying to address two improbably linked problems that hinge on a single radioactive isotope: how to reduce the risk of nuclear weapons proliferation, and how to assure supplies of a material used in thousands of heart, kidney and breast procedures a year.

They seemed to be getting close to a solution. But now General Electric, the company that developed a technology for carrying it out, has quietly dropped work on the project, saying it is not commercially viable.

The isotope is technetium 99m, or tech 99 for short. It is useful in diagnostic tests because it throws off an easy-to-detect gamma ray; also, because it breaks down very quickly, it gives only a small dose of radiation to the patient.

But the recipe for tech 99 requires another isotope, molybdenum 99, that is now made in nuclear reactors using weapon-grade uranium. In May 2009, a Canadian reactor that makes most of the North American supply of moly 99 was shut because of a safety problem. A second reactor, in the Netherlands, was simultaneously closed for repairs.

The 54-year-old Canadian reactor, Chalk River in Ontario, is running now, but its license expires in four years. Canada built two replacement reactors, but even though they turned out to be unusable, their construction discouraged potential competitors.

So the United States Energy Department, which regulates nuclear weapons, has been trying to find a way to make the molybdenum isotope without relying on leaky reactors that use bomb fuel. And in 2010 General Electric, which designs power reactors, came up with an innovative solution.

The commercial reactors have a big flow of neutrons, and if an atom of natural molybdenum absorbs one, it becomes moly 99.

G.E.’s reactors have an opening at the bottom for an instrument that measures the neutron density. The company said it could replace that monitor with a “target” made of molybdenum and pull it back out after about seven days, so it could be sent to a chemical processing plant for recovery of the moly 99.

The company even picked out a reactor, Exelon’s Clinton plant in DeWitt County, Ill. And it lined up industrial partners for the parts of the process it would not do itself, and tested the concept in research reactors.

There is a drawback, though. Only about 24 percent of natural molybdenum is moly 98, the kind that can be converted to moly 99. To produce a given volume of tech 99, the volume of molybdenum in the generator has to be far larger.

Enter another player: Perma-Fix, a company based in Atlanta that makes a resin for treating contaminants at polluted industrial sites.

The company came up with a resin that will hold the atom when it is molybdenum but release it when it decomposes into technetium. Perma-Fix executives say this is a good complement to the G.E. system.

But G.E. has given up. When the Canadian reactor was restarted, it said, it decided that its technology was not financially competitive. In a statement, G.E. said that while it and Exelon were confident “that large quantities of molybdenum 99 could safely be produced” in one of their reactors, financial projections “do not support the remaining cost.”

Kevin Walsh, a nuclear-fuel executive at General Electric, said that the company would finish developing the system if the economics improved but that for now, “we’ve put all the engineering aside.”

Louis Centofanti, chairman and chief executive of Perma-Fix, said his company was trying to line up other reactors to process the molybdenum. Federal officials say Perma-Fix may have a time advantage, because it is not using government money and thus does not have to file an environmental impact statement.

But experts say it may be nearly impossible to develop an alternative supply while highly enriched uranium is still in use, even though the reactors that do that work have an uncertain lifetime. Chalk River’s license expired last year, but it was given a single five-year extension; the Dutch reactor’s lifetime is less certain but also limited.

“The economics is key,” said Parrish Staples, director of European and African threat reduction at the National Nuclear Security Administration, who has been meeting with European officials looking for ways to stop using highly enriched uranium. The old, unreliable reactors now in use are subsidized by government, he said.

His agency backed G.E. but also a number of other companies. One, NorthStar Medical Radioisotopes, uses an accelerator to create gamma rays that bombard yet another type of molybdenum, moly 100; the bombardment causes the substance to eject a neutron and become moly 99.

Another organization, the Morgridge Institute for Research in Wisconsin, uses an accelerator to bombard uranium in a liquid solution, but it uses uranium with a much lower content of uranium 235, the kind that is useful in bombs.

And the Energy Department is helping finance a research program at Babcock & Wilcox to develop a new kind of reactor, in which uranium will be circulated in a liquid, and split; fission products, including the desired type of molybdenum, will be filtered out of the liquid for medical use.

Dr. Andrew J. Einstein, an assistant professor of clinical medicine at the Columbia University College of Physicians and Surgeons, who testified before a Senate committee in 2008 about the isotope shortage, said supplies were adequate at the moment.

But he drew a biblical analogy. “This is the seven years of plenty,” he said. “It certainly is time to be preparing for supply beyond Chalk River.”

Dr. Einstein said that when tech 99 was not available, doctors could use substitutes, but that these gave the patient larger radiation doses or provided poorer image quality to the doctor.

And for some uses, doctors can substitute PET scans, he said. But the equipment is in high demand for other procedures, and many medical facilities do not have it.

– by Matthew L. Wald/The New York Times

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Data suggest that the country has experimented with a fusion boost to its fission weapons.  

North Korea may have conducted two covert nuclear weapons tests in 2010, according to a fresh analysis of radioisotope data.

The claim has drawn scepticism from some nuclear-weapons experts. But if confirmed, the analysis would double the number of tests the country is known to have conducted and suggest that North Korea is trying to develop powerful warheads for its fledgling nuclear arsenal.

It might also explain a bizarre statement issued by North Korea’s state news agency in May 2010, which said that the country had achieved nuclear fusion. The news was largely ridiculed in the South Korean and Western media — but it was not so quickly dismissed by the small circle of experts who devote their careers to identifying covert nuclear tests. South Korean scientists had detected a whiff of radioactive xenon at around that time, hinting at nuclear activity in its northern neighbour, which had already tested nuclear devices in 2006 and 2009.

In August 2010, experts meeting in Vienna informally discussed the South Korean data and measurements from an international network of radioisotope-monitoring stations operated by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), which supports an as-yet-unratified treaty that seeks to ban nuclear-weapons testing.

Among those experts was Lars-Erik De Geer, an atmospheric scientist at the Swedish Defence Research Agency in Stockholm. When they looked at the monitoring data from Russian and Japanese stations close to North Korea, “the conclusion from everyone was, ‘Hell, we cannot explain them.’”, De Geer recalls (see ‘Nuke watching’).

Unwilling to let the matter rest, De Geer took the radioisotope data and compared them with the South Korean reports, as well as meteorological records. After a year of work, he has concluded that North Korea carried out two small nuclear tests in April and May 2010 that caused explosions in the range of 50–200 tonnes of TNT equivalent. The types and ratios of isotopes detected, he says, suggest that North Korea was testing materials and techniques intended to boost the yield of its weapons. His paper will appear in the April/May issue of the journal Science and Global Security1.

Isotope detective

De Geer’s theory rests on the detection of several short-lived radioisotopes that are generated during man-made nuclear processes.

Ratios of xenon-133 and xenon-133m (a higher-energy, ‘metastable’ form of the isotope) point towards an explosion in mid-April. The ratio of more short-lived isotopes — barium-140 and its radioactive decay product lanthanum-140 — pointed to a second test around 11 May. Indeed, the presence of barium-140 can be explained only by a sudden nuclear event, he says. “In Sweden, we saw this kind of thing decades ago from Russian underground tests.” Ratios of other xenon isotopes also point to a fast nuclear reaction that involved uranium. Until now, North Korea’s programme was thought to be based on plutonium, although rumours of a covert uranium programme have persisted for years.

De Geer speculates that North Korea is trying to build a more powerful bomb. Advanced nuclear weapons often have a small quantity of the heavier isotopes of hydrogen, known as deuterium and tritium. When a warhead detonates, it squeezes the deuterium and tritium until they fuse together. The fusion reactions release neutrons that in turn boost the fission process, increasing its yield. De Geer says that low-yield tests of the sort he suspects took place can be a first step in building a tritium-boosted weapon.

Frank von Hippel, a physicist at Princeton University in New Jersey, says that De Geer’s analysis provides convincing evidence of some kind of nuclear fission explosion. But he does not agree that it necessarily involved two weapons tests, or a fusion boost. “I hope that other experts will analyse it and see whether they can put forward alternative, simpler explanations,” he says.

Others remain deeply sceptical that the tests took place at all. Most troubling is the lack of any seismic vibrations to support the radioisotope data, according to Ola Dahlman, a retired geophysicist who spent years working with the test-ban group’s detection network. The Korean peninsula is wired to spot the tiniest shake from a nuclear explosion, Dahlman says. “It should have been able to see something.”

Far from conclusive

Jeffrey Lewis, director of the East Asia non-proliferation programme at the Monterey Institute of International Studies in California, agrees. De Geer’s hypothesis “doesn’t feel right to me”, he says. The monitoring system alone simply can’t prove that some other sort of nuclear incident, such as a reactor accident, wasn’t responsible. Dozens of reactors are currently operating in East Asia, he says, and without seismic data or on-the-ground inspections it is impossible to verify where the isotopes come from. “You need other data.”

De Geer’s arguments rest in part on data collected by the CTBTO’s network of sensors, but the organization itself has never officially analysed all these data, according to Lassina Zerbo, director of the data centre in Vienna that handles the sensor network. Zerbo says that although the data are processed and shared quickly after such an event, formal analyses are done only if requested by the CTBTO’s member states. None of the 182 signatories to the treaty ever made such a request, he says. Zerbo adds that the organization does not have access to the South Korean data mentioned in the paper, which was collected by that nation’s network of monitoring stations.   De Geer hopes that his paper will spur debate and encourage another look at the mysterious emissions. Zerbo says that it may indeed prompt scientists in CTBTO member states to re-examine the data — and then possibly to ask the CTBTO to conduct a formal analysis.

– by Geoff Brumfiel

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Houtermans Award, Nier Prize go to WUSTL assistant professor

Frédéric Moynier, PhD, 33, assistant professor in the Department of Earth and Planetary Sciences in Arts & Sciences and a member of the McDonnell Center for the Space Sciences at Washington University in St. Louis, has been named the recipient of the 2012 Houtermans Award and the Nier Prize, both given for exceptional work by a scientist younger than 35.

“We are excited to have Frédéric recognized for his outstanding work in cosmochemistry and geochemistry,” says Doug Wien, PhD, professor and chair of earth and planetary sciences. “He is an exceptionally talented and hard-working young scientist, and we are fortunate to have him in our department.

“He is always eager to talk about some new scientific development, and working with him is a delight,” Wiens says. “He has accomplished at lot in just a few short years here, so I expect he has many important discoveries ahead of him.”

“Moynier is one of the most brilliant young professors associated with the McDonnell Center for the Space Sciences,” says Ramanath Cowsik, PhD, professor of physics in Arts & Sciences and director of the McDonnell Center.

“He uses primitive meteorites as proxy for the materials out of which the Earth and other planets condensed at the time of their formation a little over 5 billion years ago. His research constitutes an important advance in our understanding of the conditions that prevailed at the time of the formation of the Earth. The center takes great pride in his achievements,” Cowsik says.

The Houtermans Award

The Houtermans Award is given annually by the European Association of Geochemistry (EAG) for exceptional contributions to the field of geochemistry.

In the award citation, the association said Moynier seeks to advance “understanding the chronology of the early solar system, the early differentiation of the Earth, the origin of the volatile elements in terrestrial planets, non mass-dependent isotopic fractionation mechanisms and the nucleosynthesis and the stellar environments at the birth of our solar system.”

‘To reach these goals, Moynier uses isotopic geochemistry tools such as short-lived radioactive nuclides and heavy stable isotopes,” the citation says.

The EAG is a pan-European organization founded to promote geochemical research. The EAG organizes conferences, meetings and educational courses for geochemists in Europe, including the Goldschmidt Conference, which it co-sponsors with the North American Geochemical Society.

Moynier, who was raised in Provence, France, earned a bachelor’s degree in geology in 2002 and a doctoral degree in 2006 from the Ecole Normale Supérieure de Lyon.

The award is named in honor of Friedrich George Houtermans, a Dutch-Austrian-German physicist who made important contributions to geochemistry and cosmochemistry even though, as a Communist in the 1930s, he ran afoul of international politics.

The award will be bestowed on Moynier at the 22nd Goldschmidt Conference in Montreal in June.

The Nier Prize

The Nier Prize is given annually by the Meteoritical Society for outstanding research in meteoritics and closely allied fields.

Moynier was recognized “for significant contributions to understanding the processes that produced isotopic fractionations in the transition metals in solar system materials.”

The Meteoritical Society is a nonprofit scholarly organization founded in 1933 to promote the study of extraterrestrial materials, including meteorites and space-mission-returned samples, and their history.

The award was established in 1995 to honor the memory of Alfred O. C. Nier, an American physicist who pioneered the development of mass spectroscopy. It is supported by a grant given by Nier’s wife, Ardis.

Moynier will receive the Nier Prize at the annual meeting of the Meteoritical Society in Cairns, Australia, in August.

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PET developer Positron has labored literally for decades to make cardiac PET a clinical reality. The company’s effort was paying off until late last year, when the market got sidetracked by a disruption in the supply of rubidium-82, the main cardiac PET radiopharmaceutical. Positron’s solution? Grow your own.

Not literally grow it, of course, but Positron has embarked on a plan to stabilize the rubidium-82 pipeline both in the short and long term by developing its own capability to produce strontium-82, the precursor isotope to rubidium-82. The company believes that a more stable supply of strontium and rubidium will lead to increased sales of its cardiac PET scanners, and help the company evolve into an end-to-end supplier of cardiac PET equipment and radiopharmaceuticals.

Positron was launched in 1983 with a focus on cardiac PET using rubidium-82. The company has stayed true to that message in the years since, and it’s now one of the only companies making a dedicated PET camera in a market that has shifted completely to PET/CT technology targeted at oncology applications.

Positron has positioned its Attrius PET system as a more economical alternative to PET/CT systems, enabling sites to move into cardiac PET at a list price of about $800,000, some $1 million cheaper than the PET/CT cameras from the major vendors, according to Pat Rooney, CEO of the company.

Positron believes that cardiac PET has a number of advantages over cardiac SPECT, which for years has been the workhorse modality for functional cardiac imaging. These include better image quality, lower radiation dose, and higher insurance reimbursement rates. Perhaps in acknowledgement of these advantages, the cardiac PET market had increased tenfold over the past five years as measured by the number of sites receiving rubidium-82 generators, according to Rooney.

Another advantage was that cardiac PET had a more stable supply of radioisotopes compared to molybdenum-99, the precursor to technetium-99m, the mostly widely used SPECT agent. Molybdenum supplies have been disrupted repeatedly over the years, with the most recent outage lasting more than a year, when the Canadian reactor that supplies the radioisotope to North America went offline in May 2009.

Cardiac PET sites produce their isotopes using generators based on strontium-82, which decays into rubidium-82. Strontium-82 is typically very expensive to produce and usually comes from government laboratories like those run by the U.S. Department of Energy, which supplies all of the strontium-82 used in the U.S. for medical purposes.

That supply had been relatively stable over the years, but the situation changed in late 2011, when Bracco Diagnostics pulled its CardioGen-82 generators from the U.S. market. Bracco was responding to concerns raised by the U.S. Food and Drug Administration (FDA) after several patients who had been injected with CardioGen-82 were found to have higher-than-expected levels of radiation after the tests.

Ultimately, Bracco and the FDA determined that the incidents were mostly likely due to user error in handling rubidium-82 generators, and the company expects to resume CardioGen-82 shipments in the first quarter of this year. But the episode lit a fire under Position executives to try to gain more control of their own destiny.

“We recognized that a sole-source supplier could lead to instability or reluctance from buyers,” said Joseph Oliverio, chief technology officer and director of clinical programs at Positron. “We are taking the responsibility to stabilize and increase the strontium supply within the market.”

Positron earlier last month closed on its acquisition of Manhattan Isotope Technology, which specializes in the processing of strontrium-82 at a facility in Lubbock, TX. In the first quarter, the Lubbock site will begin receiving strontium-82 from a cyclotron operated by Arronax in France, and will offer it to companies such as Bracco pending the approval of a drug master file by the FDA.

Farther down the road, Positron is developing a longer-term supply by building its own 70-MeV cyclotron facility, to be operated at a site in Noblesville, IN. The company has received $6.7 million in tax incentives from the local government, as well as a $38 million private bond that will be granted by the state of Indiana, allowing investors to invest in the project tax-free while Positron receives the proceeds. Rooney estimates that it will take three years to build the cyclotron facility. At that point, Positron will be able to produce strontium-82 on its own.

All told, the company hopes that its short- and long-term efforts will bolster the confidence of sites debating a switch to cardiac PET but apprehensive about radioisotope supplies.

“We believe that PET is the new SPECT,” Rooney said. “We don’t think it replaces SPECT, but there is a great movement from SPECT to PET. PET is much better for the patient, practice, and payors than SPECT.”

– by Brian Casey/AuntMinnie.com

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Ah, fusion. Long promised, both on Do the Math and in real life, fusion is regarded as the ultimate power source—the holy grail—the “arrival” of the human species. Talk of fusion conjures visions of green fields and rainbows and bunny rabbits…and a unicorn too, I hear. But I strike too harsh a tone in my jest. Fusion is indeed a stunningly potent source of energy that falls firmly on the reality side of the science fiction divide—unlike unicorns. Indeed, fusion has been achieved (sub break-even) in the lab, and in the deadliest of bombs. On the flip side, fusion has been actively pursued as the heir-apparent of nuclear fission for over 60 years. We are still decades away from realizing the dream, causing many to wonder exactly what kind of “dream” this is.

Our so-far dashed expectations seem incompatible with our sense of progress. Someone born in 1890 would have seen horses give way to cars, airplanes take to the skies, the invention of radio, television, and computers, development of nuclear fission, and even humans walking on the Moon by the age of 79. Anyone can extrapolate a trajectory, and this trajectory intoned that fusion would arrive any day—along with colonies on Mars. Yet we can no longer buy a ticket to cross the Atlantic at supersonic speeds, and the U.S. does not have a human space launch capability any more. Even so, fusion remains “just around the corner” in many minds.

I am sympathetic to delayed predictions, and the fact that fusion has failed to deliver on the promise that it’s “just around the corner” for decades does not mean that it will never arrive. I can compare this to Malthus’ insight that exponential population growth was on a collision course with finite agricultural capability, or to various warnings about collapse along the way. Just because the predictions have not yet been satisfied does not mean that they will not be someday. In fact, the two divergent predictions become related. If we can manage to hold it together this century and maintain a high-tech civilization during our forced transition off of fossil fuels, it becomes far more likely that we will get to the point of employing fusion. If, on the other hand, we overshoot and collapse, we may descend too far to viably pursue fusion this century.

What’s fusion all about, anyhow? …

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– by Tom Murphy/OilPrice.com

Tom is an associate professor of physics at the University of California, San Diego. This post originally appeared on Tom’s blog Do the Math.