Explainer: What is RNA?

By Merlin Crossley

Our genetic material is encoded in DNA (deoxyribonucleic acid).

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DNA is famous. But you may also have also heard of RNA (ribonucleic acid). So, what is RNA, and what is it good for?

Quite a lot really. In fact, it is possible that early life used RNA as its genetic material and also used folded RNAs as chemical tools to survive. This is called the RNA world hypothesis.

RNA is similar to DNA in lots of ways. It is a long chain of sugars linked together by phosphate groups. There is a cyclic base attached to each sugar and the bases can pair with matching partners to make a double helix.

This resembles DNA but the helix is a bit contorted and often RNAs are folded into complex structures stabilised by short helices interspersed with long single-stranded loops.

The really important difference is that RNA has an extra oxygen molecule. This makes RNA less stable than DNA.

Ribose, on the left, has one extra oxygen molecule compared to deoxyribose, right. Wikimedia Commons

You might think that being unstable is a bad thing, but there are advantages. Organisms that need to change rapidly tend to use RNA as their genetic material. Viruses, such as influenza and HIV, choose RNA rather than the more stable alternative of DNA so they can change and keep one step ahead of the immune system of their hosts.

Many factors contribute to the high mutation rates in RNA viruses, including the instability of RNA and the poor proof reading activity in the enzymes that replicate RNA.

Messenger service

Like DNA, RNA is a long chain of sugars. Sponk

As well as serving as genetic material, RNA has another critical function in virtually all organisms: it acts as a messenger; a short-lived intermediate communicating the information contained in our genes to the rest of the cell.

Many genes need to be turned on in bursts. Think of a football fan shouting out at a key point in a game – we don’t want the message to last forever.

Genes do last a lifetime, so how do we provide short-lived messages?

We make RNA copies of our DNA genes. The messages, or mRNAs, reflect the sequence of bases in our DNA and travel out of the nucleus (where our DNA is stored) into the cytoplasm where they are translated into proteins. The proteins go on to do jobs in the cell and the unstable mRNAs simply decay or are degraded.

So RNA can act as a messenger in the process of ensuring genes are translated into proteins – the tools of the cell, things such as haemoglobin to carry oxygen round the body.

But how does this mysterious translation occur? Does it rely on chemical tools such as proteins?

It certainly does, but it seems that the proteins are not the key players. It is a remarkable fact that the really important players in triggering the chemical reactions to produce protein chains from the mRNA code are not other proteins, but specially folded RNA molecules – RNA enzymes or ribozymes.

The machinery for reading a protein from a messenger RNA is contained in a complex RNA enzyme and the functional parts are RNA molecules called ribosomal RNAs or rRNAs.

RNA enzymes or ribozymes trigger the mRNA translation process.

Securing information

How come RNA can trigger chemical reactions but DNA doesn’t seem to? It is partly the extra oxygen and partly the special ability RNA has to fold up into complex shapes to form tools that can do things, whereas the double helix is regular and stable. The DNA double helix holds information securely but doesn’t do much else.

In 1989 Sidney Altman and Thomas Cech shared the Nobel Prize in Chemistry for demonstrating that RNAs could catalyze chemical reactions.

You might wonder how a chain of sugars and bases such as mRNA can even serve as a template for forming a protein chain. The answer is complicated but it involves some clever adaptors. Amazingly, those adaptors are also made of RNA, they’re called transfer RNAs or tRNAs. They use their cyclic bases to pair to their mirror images in the mRNA and line up the right amino acids to make the protein, while the rRNA triggers the reaction to do the joining.

Structure of a transfer RNA (tRNA) molecule Image from shutterstock.com

The finding that absolutely essential functions such as encoding information, having a short-lived messenger to express it, and converting it into a set of functional protein tools, all involve RNA has led people to hypothesise that early life was made up of RNA.

In the beginning RNA possibly did the lot. But then gradually DNA took over as a more stable genetic material and proteins took over as more stable chemical tools. And RNA was gradually forgotten by some researchers, at least until recently.

Future of RNA

In 1998, American biologists Andy Fire and Craig Mello discovered RNA inhibition – how RNA can switch off genes.

We now know that a new class of small inhibitory RNAs (siRNAs which are about 20 residues long), fine tune the output from messenger RNAs. As mentioned RNA can form double strands – this allows siRNAs to bind messenger RNAs and interfere with their function.

These interfering RNAs are essentially “digital” inhibitors that are base for base mirror images of the messenger RNA. So it possible to make artificial inhibitors now. Thus a new industry has been born as researchers strive to turn genes off for experimental purposes and medical researchers investigate whether this can be used for therapies, such as turning off viruses or other harmful genes.

There has also been another interesting discovery – researchers have found that although only a small part of our genome encodes protein, around 2%, a much larger proportion is still copied into RNA.

The function of many of these long non-protein coding RNAs, called lncRNAs, is still being investigated but it seems that some act to catalyse chemical reactions and that others are involved in turning genes on or off either by binding messenger RNAs or by binding directly to the DNA genes they match.

If the world began with RNA then it is not really surprising that echoes of that RNA world remain and that RNAs are still involved in key life processes and are fundamentally important in gene regulation.

New classes of RNA molecules will continue to be discovered and it is seems likely that further insights into fundamental biology will emerge from this fertile ground in the future.

Merlin Crossley receives funding from the University of New South Wales, the Australian Research Council and the National Health and Medical Research Council.


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Life on South Asia’s shifting river islands

Imagine going to sleep at the end of the day, with every possibility your home could be washed away overnight.

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It’s an everyday reality for the millions of people who reside on the sandbars of South Asia’s Bay of Bengal delta.

Known as char-dwellers, seasonal flooding and riverbank erosions mean these people play a lottery with nature – at any time homes and assets can be washed away.

Their lives are documented in a new book, Dancing with the River, by Kuntala Lahiri-Dutt of the Crawford School of Public Policy in the ANU College of Asia and the Pacific, and Gopa Samanta from the University of Burdwan.

In their groundbreaking book, the authors explore the world of chars—the part land, part water, low lying sandy masses that exist within the riverbeds in the flood plains of lower Bengal.

In West Bengal, chars are used by the poorest and ‘most wretched of the earth’, including homeless Bihari and Bangladeshi Hindu migrants, the authors point out.

Often ideal for agricultural purposes, the chars are formed through rivers washing sandy, silty material down mountains and into the sea – much of which is stored temporarily in the form of river islands.

For the purpose of their research, Lahiri-Dutt and Samanta examined 11 chars across the former region of Bengal.

“In Bangladesh people have accepted the existence of chars,” says Lahiri-Dutt.

In India, however, those who lived on them were viewed as illegal citizens.

“There is no government record of the property existing,” says Lahiri-Dutt, “so chars are not legally owned.”

Abrupt falls in market prices for agricultural products, physical isolation, and illness are other realities. Additionally, boundaries are in constant flux, and the remoteness and lack of accessibility mean a total lack of health care, sanitation, water and electricity supplies.

On the upside, the book’s authors argue that some inhabitants might feel more secure living on chars than among hostile neighbours.

Several make plans for a long-term stay, others, fully aware of their vulnerability, use them as a temporary place of residence while making plans to live in mainland areas.

Lahiri-Dutt does not, by any means, perceive char-dwellers as victims, preferring to focus on their resilience, rather than calling on governments to lend support.

“The fact that poor people live on the most marginal of environments is well known,” she says.

“But, we live with risk every day. We live with worries and tension.

The day-by-day approach to life by char-dwellers offered “a profound experiential view of living with a highly changeable and non-benign nature,” Lahiri-Dutt emphasises.

Adaptation was the key to their survival.

“What is not well known is how poor people deal with the vulnerabilities and the risks that arise from living in these sorts of marginal environments,” says Lahiri-Dutt.

“Char-dwellers don’t plan for six months, or six years, they plan for today.”

While the thought of one’s home being washed away over night was not a happy one, the idea of everything being temporary and contingent was not necessarily bad either.

“We are hardwired to believe that permanent is good,” says Lahiri-Dutt.

Dancing with the River is published by Yale University Press.

This article is from the Australian National University’s College of Asia and the Pacific


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Dead ducks removed from Chinese River

The ducks, which were found in around 50 plastic woven bags, were fished out of a section of the Nanhe River by authorities in the southwestern Chinese province of Sichuan, the official Xinhua news agency said.

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The animals were then buried in plastic bags three meters underground, but the report did not specify how the ducks had died.

The report has come after Shanghai officials said a cleanup was close to ending after an embarrassing pollution case which saw 16,000 dead pigs floating down the city’s main river.

“The city’s water territory has already basically finished the work of fishing out the floating dead pigs,” a Shanghai government statement released late on Sunday said.

China’s commercial hub recovered 98 pigs on Sunday from the Huangpu river and 93 on Saturday, the authorities said, the first time the daily toll had fallen below a hundred in days.

The total number Shanghai had removed from the river, which supplies 22 percent of the city’s drinking water, had reached 10,924 as of Sunday afternoon.

In addition, Jiaxing in neighbouring Zhejiang province, whose farmers are accused by Shanghai of dumping the dead pigs into the river upstream, had found 5,528 carcasses, state radio said last week.

Mystery remains over the exact origin of the dead hogs. Jiaxing has insisted it was not the sole source, while Shanghai said its farms have not reported an epidemic which would kill pigs in such large numbers.

The images of dead pigs in China’s commercial hub have proved a huge embarrassment for the city, which is seeking to grow as an international financial centre.

The scandal has highlighted China’s troubles with food safety, adding the country’s most popular meat to a growing list of food items rocked by controversy.

Animals that die from disease can end up in China’s food supply chain if improperly disposed of, despite laws against the practice.

Samples of the dead pigs have tested positive for porcine circovirus, a common swine disease that does not affect humans.


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South Africa probes death of man ‘dragged by police van’

South Africa has opened a murder investigation into the death of a Mozambican taxi driver who was filmed being dragged by a police van through the streets, in a case that has sparked widespread outrage.

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Video footage taken by a bystander shows 27-year-old Mido Macia tussling with half a dozen police officers before being handcuffed to the back of a police van and dragged to a local police station in Daveyton, east of Johannesburg, on Tuesday.

A large crowd of horrified bystanders looked on, some warning the uniformed officers they were being filmed. “Hey! Hey! Why are you hitting him?” one person in the crowd can be heard shouting in Zulu.

Kicking and struggling to avoid the tarmac, Macia was taken into custody at Daveyton police station and was found dead less than two hours and 25 minutes later, according to investigators.

A post mortem found the cause of death was head injuries with internal bleeding.

South African President Jacob Zuma condemned the killing as “horrific, disturbing and unacceptable”.

“No human being should be treated in that manner,” he said in a statement.

The Independent Police Investigative Directorate said it had opened a murder investigation.

“We are investigating an incident involving the death of man, allegedly at the hands of the police. We are shocked by the footage which has been released,” said Independent Police Investigative Directorate spokesman Moses Dlamini.

“The circumstances surrounding his death are still allegations… let’s find out what really happened,” he said.

The police watchdog and witnesses said two officers initially confronted Macia for parking his Toyota Avanza taxi illegally.

Eyewitnesses said Macia had been trying to get his driving license back from the police when an altercation occurred. But witnesses denied police suggestions the victim had tried to disarm one of the officers.

“He was just pushing them, not trying to take the gun,” said George Nxumalo, a 57-year-old Daveyton resident.

Around half a dozen officers were at the scene soon after, some clad in stab vests and at least one brandishing a pistol.

The taxi driver was found dead in his cell at around 21:15 (1915 GMT).

Footage of the incident spread quickly online, sending shockwaves through the country.

Daveyton residents marched on the police station on Thursday after claiming they were dispersed with pepper spray the day before.

“They are criminals in uniform, we don’t want them, we want the law to take its course, otherwise we will take the law into our own hands,” said Bongani Hlela, a street trader based at the taxi rank were the incident occurred.

“Just because he was Mozambican does not mean that he should be treated badly. We are all African, we have rights,” he added.

The Mozambique government said it was “outraged by what happened”.

“It is very sad that a life was lost so stupidly,” Foreign Affairs Minister Oldemiro Baloi told reporters in the capital Maputo.

“I think that whatever perspective you want to attach to it — either human or the relations between the two countries — it is absolutely unacceptable.”

South African police commissioner Riah Phiyega expressed “deep concern” about the incident, saying it was being viewed “in a very serious light”.

The police department said no officers had been suspended yet in the case.

Macia’s death is the latest in a series of crises to hit the country’s beleaguered police service, which was pilloried for the shooting deaths of 34 miners last August and for its handling of the Oscar Pistorius case.

“This appalling incident involving excessive force is the latest in an increasingly disturbing pattern of brutal police conduct,” said Noel Kututwa, Amnesty International’s southern Africa director.

The Independent Police Investigative Directorate received 720 new cases for investigation of suspicious deaths in custody or in other policing contexts from April 2011 to March 2012, according to Amnesty.

The opposition Democratic Alliance party called for a full investigation by South Africa’s human rights commission and for the officers involved to be suspended.

“Macia paid for parking on the wrong side of the road with his life. Instead of issuing him with a ticket, the police killed him,” said shadow police minister Dianne Kohler Barnard.

“How much longer must South Africans live in fear of the very people who are supposed to protect them?”


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NKorea on strike standby after US drill

The order came as US Defense Secretary Chuck Hagel, with tensions soaring on the Korean peninsula, said Washington would not be cowed by Pyongyang’s bellicose threats and stood ready to respond to “any eventuality”.

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Kim directed his rocket units on standby at an overnight emergency meeting with top army commanders, hours after nuclear-capable US B-2 stealth bombers were deployed in ongoing US joint military drills with South Korea.

In the event of any “reckless” US provocation, North Korean forces should “mercilessly strike the US mainland… military bases in the Pacific, including Hawaii and Guam, and those in South Korea”, he was quoted as saying by the official Korean Central News Agency (KCNA).

While North Korea has no proven ability to conduct such strikes, Kim said: “The time has come to settle accounts with the US imperialists.”

The youthful leader argued that the stealth bomber flights went beyond a simple demonstration of force and amounted to a US “ultimatum that they will ignite a nuclear war at any cost”.

An unidentified South Korean military official quoted by Yonhap news agency said a “sharp increase” in personnel and vehicle movement had been detected at the North’s mid- and long-range missile sites.

The United States rarely acknowledges B-2 flights to the Korean peninsula, which remains technically at war. The aircraft, which dodge anti-aircraft defences, bombed targets in conflicts in Serbia, Afghanistan, Iraq and Libya.

The flights came as part of annual drills between the United States and South Korea, which North Korea each year denounces as rehearsals for war.

Pyongyang has been particularly vocal this time, angered by UN sanctions imposed after its long-range rocket launch in December and the third nuclear test it carried out last month.

Kim’s order formalised steps already taken by the Korean People’s Army (KPA), which put its strategic rocket units at combat-ready status on Tuesday. The following day it cut the last remaining military hotline with South Korea.

The bulk of the threats emanating from Pyongyang have been dismissed as bluster, and North Korea has no confirmed missile capability to reach the US mainland — or indeed Guam or Hawaii in the Pacific.

But Washington has opted to match the threats with its own muscle-flexing.

“We will be prepared — we have to be prepared — to deal with any eventuality,” Hagel told reporters at the Pentagon.

“We must make clear that these provocations by the North are taken by us very seriously and we’ll respond to that,” Hagel said, defending the B-2 deployment.

US military intelligence has noted that the North’s warlike rhetoric has not, so far, been matched by any overtly provocative troop build-up.

Pyongyang has also been careful not to allow tensions to affect the Kaesong industrial complex, a joint South-North venture that provides the regime with crucial hard currency.

Present at the emergency meeting convened by Kim in Pyongyang were the KPA chief of general staff, director of operations and commander of strategic rocket operations.

KCNA provided an unusually precise timing for the meeting of 00:30 am (1530 GMT Thursday) in an apparent effort to underline the urgency and import of Kim’s order.

But analysts warned against reading too much into what is the latest in a long series of incremental rhetorical upgrades.

“It shouldn’t be taken to mean war is imminent,” said Kim Yong-Hyun, a North Korea expert at Dongguk University.

“It’s an inevitable and calibrated reaction to the B-2 deployment, and this who-blinks-first game with the United States will continue for a while yet,” he said.

On the assumption that the North would never invite a full-scale conflict it would surely lose, experts believe it may opt for a limited provocation, similar to its 2010 shelling of a South Korean island that killed four people.


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Three Afghans killed in attack on US base

A Taliban suicide car bombing has hit a US-run base in eastern Afghanistan, killing at least three Afghans and wounding seven others.

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Afghan interior ministry spokesman Sediq Sediqqi said the attack on Wednesday was a suicide car bombing and happened near the entrance of Forward Operating Base Chapman in Khost, a Taliban flashpoint that borders Pakistan.

“Three Afghan nationals are killed and seven Afghan nationals are wounded. We have no report of coalition casualties right now,” said Major Martin O’Donnell, a spokesman for NATO’s International Security Assistance Force (ISAF).

The blast was so powerful that it rattled the windows of buildings in the city, some four kilometres away, an AFP journalist said.

In December 2009 an al-Qaeda triple agent blew himself up at FOB Chapman, killing seven CIA agents and his Jordanian handler, the deadliest attack on the US intelligence agency since 1983.

The Taliban, which has waged a bloody insurgency against foreign and Afghan government forces for the past 11 years since being ousted from power in an invasion led by the US, claimed Wednesday’s attack.

“The attack was carried out by a mujahid named Omar from Khost who knew the area very well,” Taliban spokesman Zabihullah Mujahed told AFP by email.

He said the attacker “detonated a car bomb while American invading forces were searching visitors going to the base”. In August 2010, 24 Taliban militants, some wearing US uniforms, were killed when they tried to storm Camp Chapman and another nearby US base, Camp Salerno, which was also the target of a suicide truck bombing in June this year.

Khost is one of the most volatile parts of Afghanistan, sharing a porous border with Pakistan’s tribal belt, which lies outside government control, and where US officials say the Taliban and al-Qaeda have carved out rear bases for operations in Afghanistan.


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Melbourne boy rallies funds for Yemen shooting victim

Saleem al-Harazi was on a mission to buy eggs and milk for his family in Sana’a, the capital of Yemen, when his life was changed forever.

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As he walked through Change Square, the 11-year-old was shot in the face by a sniper during the bloodiest day in Yemen’s recent history.

VISIT Saleem’s fundraiser page, set up by Jylon and Iona

It was March 18 2011 and the Arab Spring had just begun to ripple through the region.

Saleem al-Harazi recovers in hospital after after being shot in the face in Yemen’s Change Square during a day of protest. (Image: Iona Craig)

More than a year later, and after losing both his eyes, Saleem’s life is starting to return to normal, but his story has become one of the tragic symbols of the human impact of Yemen’s Revolution.

It was through a haunting image in National Geographic magazine that Jylon Grandy, a 10-year-old schoolboy from suburban Melbourne, first stumbled across Saleem’s story.

“I came across this page and Saleem al-Harazi was sitting on a couch with his mum. I looked at his eyes and thought ‘where did they go?’” he explains.

Jylon’s mother Sharon says reading about Saleem’s shooting “deeply upset” her son. “We couldn’t console him. It was a very emotional evening.”

Unable to shake the idea that a child on the other side of the world had experienced such a horrific incident, Jylon — largely unprompted by his parents — came up with a plan to raise money to help the young Yemeni boy.

“I was brainstorming what I could do for him, and I came up with the best idea: a walk-a-thon.”

Supported by his parents and his school, Jylon’s plan started ticking into action.

The family contacted Iona Craig, a freelance journalist currently based in Yemen, who was in Change Square with tens of thousands of others the day Saleem was shot.

LISTEN: Iona Craig talks about the shootings in Change Square on March 18


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Scientists track whales by following their songs

An Australian-led group of scientists has for the first time tracked down and tagged Antarctic blue whales by using acoustic technology to follow their songs, the government said today.

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The blue whale, the largest animal on the planet, is rarely spotted in the Southern Ocean but a group of intrepid researchers were able to locate and tag some of the mammals after picking up on their deep and complex vocals.

Environment Minister Tony Burke said the researchers, who spent seven weeks working from small boats in freezing Antarctic conditions, were captivated by the remarkable behaviour of the whales they saw.

“The Antarctic blue whale can grow to over 30 metres in length and weigh up to 180 tonnes, its tongue alone is heavier than an elephant and its heart is as big as a small car,” Burke said.

“Even the largest dinosaur was smaller than the blue whale.”

The scientists collected 23 biopsy samples and attached satellite tags to two of the whales.

“The tags transmitted never-before obtained data on rapid longitudinal movements during their summer feeding season and their foraging behaviour in relation to the edge of the Antarctic ice,” tagger Virginia Andrews-Goff said.

“This method of studying Antarctic blue whales has been so successful it will now become the blueprint for other whale researchers across the world.”

The inaugural Southern Ocean trip of the Antarctic Blue Whale Project involved deploying acoustic buoys west of the Ross Sea to pick up blue whale songs, which can be detected from hundreds of kilometres (miles) away.

They recorded 626 hours of songs, with 26,545 calls of Antarctic blue whale analysed in real time, said lead acoustician Brian Miller.

“The researchers were then able to triangulate the position of the whales from their vocalisations and direct the ship to the target area,” he said.

Burke said the study proved it was not necessary to kill whales to conduct scientific research, a reference to Japan’s annual whale hunt in the Antarctic, which is conducted in the name of scientific research.

“The Antarctic blue whale barely escaped extinction during the industrial whaling era in the 1900’s when around 340,000 whales were slaughtered,” Burke said in a statement.

“This research reinforces Australia’s commitment to non-lethal research of whales.”


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NKorea on agenda as Kerry hits Japan

He was due to meet Japanese Foreign Minister Fumio Kishida later in Tokyo, which has deployed Patriot missiles around the capital in anticipation of a missile launch by the North.

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Japanese Defense Minister Itsunori Onodera said he expected the top US and Japanese diplomats to send a strong signal urging North Korea to listen to the international community.

“It is important that we coordinate internationally and firmly tell North Korea that it must give up its nuclear and missile programmes,” Onodera told reporters, adding he hoped Kishida and Kerry would issue a “strong message”.

Kerry’s visit follows an intense day of diplomacy Saturday in Beijing, where he warned Chinese leaders including President Xi Jinping that the stakes were high as China’s erratic ally North Korea threatens a missile launch.

China is Pyongyang’s sole major ally and backer, and is widely seen as the only country with leverage to influence its actions — although it is also reluctant to risk destabilising the regime.

“The importance of the visit yesterday really cannot be overstated,” Kerry told US embassy staff in Beijing on Sunday ahead of his departure for Tokyo.

“This is a critical time needless to say, being able to speak directly to my Chinese counterpart and try to focus on some very critical issues is of major importance.”

State Councillor Yang Jiechi, who is in charge of Beijing’s foreign policy, said China was committed to “advancing the denuclearisation process on the Korean peninsula” and “will work with other relevant parties including the United States to play a constructive role”.

Kerry said China and the United States “must together take steps in order to achieve the goal of a denuclearised Korean peninsula” and were “committed to taking actions”.

But neither side gave details of any specific measures, and the top US diplomat said there would be “very focused continued high-level discussions about the ways to fill in any blanks”.

Kerry told reporters he wanted to ensure that Saturday’s pledges were “not just rhetoric, but that it is real policy”.

He predicted he would be making “many trips” to Beijing, hailing what he called “an extremely positive and constructive day… beyond what I anticipated in many regards”.

The US Chairman of the Joint Chiefs of Staff Martin Dempsey is to visit Beijing this month along “with other members of the intel community”, he added.

The secretary of state previously held talks in South Korea with President Park Geun-Hye, where he offered public support for her plans to initiate some trust-building with the North.

The region has been engulfed by threats of nuclear war by Pyongyang in response to UN sanctions imposed over its recent rocket and nuclear tests, and Kerry stressed that China, which has backed Pyongyang since the 1950-53 Korean War, holds a unique sway over it and leader Kim Jong-Un.

China is estimated to provide as much as 90 percent of its neighbour’s energy imports, 80 percent of its consumer goods and 45 percent of its food, according to the US-based Council on Foreign Relations.

But analysts say it is wary of pushing too hard for fear of a regime collapse sending waves of hungry refugees flooding into China and ultimately leading to a reunified Korea allied with the United States.

“Mr President, this is obviously a critical time with some very challenging issues,” Kerry told Xi earlier in the Great Hall of the People.

As well as “issues on the Korean peninsula”, he cited Iran’s nuclear ambitions, Syria and the Middle East, and the world’s economic woes.

Strains in the relationship between the United States and China, the world’s top two economies, have been simmering on an array of diplomatic fronts including Syria and Iran, as well as trade.

Xi did not mention Korea at the start of his talks with Kerry, but said the China-US relationship was “at a new historical stage and has got off to a good start” since his ascension as head of state last month.

But in a commentary issued minutes later, China’s official Xinhua news agency said America’s strategic “pivot to Asia” could breed mistrust, and Washington should “help seek reasonable and workable solutions to regional issues”.

Kerry again warned that any missile launch by the North in the coming days would be seen as “provocative”.

But he raised the possibility that “if the threat disappears” and North Korea denuclearises, Washington could stand down its forces as it would no longer have “the same imperative… to have that kind of robust, forward-leaning posture”.


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Victoria quake didn’t do much damage, ‘but next one might’

By Tim Rawling, University of Melbourne

Just before 9pm last night (AEST) a magnitude-5.

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4 earthquake (initially measured as magnitude-5.3) rocked Victoria. The quake did minimal damage to property and no injuries have been reported, but it reminded us that the bit of the earth’s crust we live on isn’t as stable and quiet as we might often think.

The quake’s epicentre was located 10km southwest of Moe and occurred roughly 10km below the surface. It was the equal-largest earthquake to have occurred in Victoria since the magnitude-5.7 earthquake that occurred near Mount Hotham in 1966.

(Another magnitude-5.4 earthquake struck Wonnangatta in eastern Victoria in 1982).

Last night’s quake was centred roughly 10km southwest of Moe. Google Maps

The public perception of earthquake hazards in Australia tends to be based largely on personal experience.

Many of us will have experienced small earthquakes or tremors but for the most part these are located far from built up areas and tend not to produce much more than a flurry of Facebook and Twitter updates, and perhaps the occasional website crash.

Many of you might remember the magnitude-5.6 Newcastle earthquake in 1989 which killed 13 people, left more than 100 injured and caused an estimated US$1.1 billion worth of damage. But unless you were directly affected by the tragedy of that event you probably don’t consider such an event likely to occur in Australia again.

Indeed, it’s easy to forget we live on a very dynamic continental plate. The Australian Plate (see image below) is actually one of the fastest moving on the planet, charging northwards at a rate of 7cm/year. Consequently, our continent is relatively highly stressed and more prone to earthquakes than we might expect.

Moe is nowhere near the edge of the Australian Plate, which is drifting north at a rate of 7cm per year. Mike Sandiford

One look at a map, or a drive along the coast, reveals evidence of large seismic events in our geological past. Not far from the recent Moe earthquake, the tilting of beach deposits at Warratah Bay suggests multiple, large earthquake rupture events have occurred in the region’s very recent geological past.

Further north, the development of a fault scarp – a cliff-like embankment – on the Cadell Fault has changed the course of the Murray River near Echuca several times in the past 100,000 years. These events must have been huge, on the order of magnitude 7 or greater.

More recently (geologically speaking), activity on an unnamed fault off the coast of South Australia near Beachport in 1897 caused a significant magnitude-6.5 earthquake. That earthquake is recorded as having rung church bells as far away as Bendigo.

Last night’s quake could have been felt more than 250km away from the epicentre. Geoscience Australia

Last night’s earthquake was what is known as an intraplate earthquake – that is, it occurred away from an active tectonic plate boundary.

Active plate boundary earthquakes, such as the Tōhoku-Oki earthquake of March 2011 (which led to the Fukushima nuclear disaster) and the April 2012 earthquake off the coast of the Indonesian province of Aceh are well known to be devastating but intraplate earthquakes can also be very damaging.

The magnitude-6.3 earthquake that hit Christchurch in February 2011 was about 150km east of the tectonic plate boundary, and was part of a sequence of shallow intraplate earthquakes. And yet this earthquake killed roughly 180 people and caused tens of billions of dollars damage.

The epicentre of the Christchurch event was characterised by a pattern of high-amplitude, high-frequency and short-duration “strong motion”. Strong motion implies that monitoring seismometers were overwhelmed in the event.

This pattern of “strong motion” is typical of that observed in relatively shallow intraplate Australian earthquakes and hints at what we could expect, should a quake of similar size occur here. With a similar magnitude event occurring, on average, once every five to ten years across Australia, that’s not an impossibility.

Seismograph of last night’s quake, taken between 8.53pm to 8.56pm (AEST), from Toolangi, Victoria. Geoscience Australia

This potential is the driver behind Australian research attempting to better understand stress in the earth’s crust, and the resulting earthquake hazard. Scientists working on the current monitoring networks run by Geoscience Australia, Environmental Systems and Services (ES&S) and AuScope are seeking to improve instrumentation to more accurately locate seismic events and better understand the forces that resulted in those events. Further research is also needed into how continental earthquakes behave and how they are triggered on the Australian Plate.

Public and institutional perception of “low risk” is one of the reasons researchers are seeking an improved understanding of Australia’s crustal stability. Our lack of a collective experience of damaging earthquakes in Australia has meant that government and local authority planning – related to earthquake risk – is very poor compared with neighbouring regions of “higher risk” (such as New Zealand).

New hazard data and maps are currently being developed by a number of research groups (such as the Victorian Earthquake Hazard Map at the University of Melbourne, funded by the Natural Disaster Resilience Grant) to underpin the establishment of new planning codes and disaster management strategies that specifically consider seismic hazard.

Nascent energy technologies – such as geothermal energy, geological carbon storage and unconventional gas – provide further research directions in terms of crustal stability.

These developing technologies typically involve injecting or removing fluids from the earths crust. So a detailed understanding of the natural background seismicity of prospective regions is critical to mitigating against anthropogenically triggered seismicity. It also reduces the potential for naturally occurring events to negatively impact public opinion on these important projects.

In the meantime, last night’s earthquake will probably serve to remind many of us that the earth beneath our feet isn’t as stable as we might think.

Tim Rawling receives funding from the Natural Disaster Resilience Grants Scheme. He is affiliated with the Australian Geophysical Observing System.


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