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杭州夜生活

‘Dragon thief’ thrived after calamity

In the early years of the Jurassic Period, when the world was recovering from one of the worst mass extinctions on record, a modest meat-eating dinosaur from Wales helped pave the way for some of the most fearsome predators ever to stalk the earth.

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Scientists on Wednesday announced the discovery of fossil remains of a two-legged dinosaur called Dracoraptor that lived 200 million years ago and was a forerunner of much later colossal carnivores like Tyrannosaurus rex, Allosaurus and Spinosaurus.

Dracoraptor means “dragon thief”. The Welsh flag bears a red dragon.

The fossil is of a 2.1m juvenile, with adults reaching perhaps 3m, said paleontologist Steven Vidovic of Britain’s University of Portsmouth.

At the Triassic Period’s end, not long before Dracoraptor appeared, roughly half of earth’s species became extinct.

Scientists are uncertain of this primordial calamity’s cause. Hypotheses include an asteroid impact like the one that doomed the dinosaurs 66 million years ago, volcanic activity or climate change.

This mass extinction event that ushered in the Jurassic was pivotal in letting dinosaurs become the dominant land animals.

The biggest land predators at the end of the Triassic were not dinosaurs, but rather rauisuchians, big four-legged reptiles. Rivers teemed with phytosaurs, huge crocodile-like reptiles.

Both these groups disappeared in the mass extinction, clearing the way for dinosaur carnivores that until then were only moderate in size to become the top terrestrial predators.

Vidovic said the Dracoraptor fossils, discovered in 2014 on a beach near the Welsh town of Penarth, represent some of the most complete dinosaur remains from this time, with 40 per cent of the skeleton unearthed.

“So this dinosaur starts to fill in some gaps in our knowledge about the dinosaurs that survived the Triassic extinction and gave rise to all the dinosaurs that we know from Jurassic Park, books and TV,” Vidovic said.

“Dinosaurs diversified and populated the ecological niches in the Early Jurassic.”

It was an early representative of the theropod group that included the likes of T. rex, and had the same general shape as that beast, although much smaller.

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The last time Earth was this hot hippos lived in Britain (that’s 130,000 years ago)

Emma Stone, University of Bristol and Alex Farnsworth, University of Bristol

It’s official: 2015 was the warmest year on record.

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But those global temperature records only date back to 1850 and become increasingly uncertain the further back you go. Beyond then, we’re reliant on signs left behind in tree rings, ice cores or rocks. So when was the Earth last warmer than the present?

The Medieval Warm Period is often cited as the answer. This spell, beginning in roughly 950AD and lasting for three centuries, saw major changes to population centres across the globe. This included the collapse of the Tiwanaku civilisation in South America due to increased aridity, and the colonisation of Greenland by the Vikings.

But that doesn’t tell the whole story. Yes, some regions were warmer than in recent years, but others were substantially colder. Across the globe, averaged temperatures then were in fact cooler than today.

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To reach a point when the Earth was significantly warmer than today we’d need to go back 130,000 years, to a time known as the Eemian.

For about 1.8m years the planet had fluctuated between a series of ice ages and warmer periods known as “interglacials”. The Eemian, which lasted around 15,000 years, was the most recent of these interglacials (before the one we’re currently in).

Although global annual average temperatures were approximately 1 to 2˚C warmer than pre-industrial levels, high latitude regions were several degrees warmer still. This meant ice caps melted, Greenland’s ice sheet was reduced and the West Antarctic ice sheet may have collapsed. The sea level was at least 6m higher than today.

Across Asia and North America forests extended much further north than today and straight-tusked elephants (now extinct) and hippopotamuses were living as far north as the British Isles.

How do we know all this? Well, scientists can estimate the temperature changes at this time by looking at chemicals found in ice cores and marine sediment cores and studying pollen buried in layers deep underground. Certain isotopes of oxygen and hydrogen in ice cores can determine the temperature in the past while pollen tells us which plant species were present, and therefore gives us an indication of climatic conditions suitable for that species.

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We know from air bubbles in ice cores drilled on Antarctica that greenhouse gas concentrations in the Eemian were not dissimilar to preindustrial levels. However orbital conditions were very different – essentially there were much larger latitudinal and seasonal variations in the amount of solar energy received by the Earth.

So although the Eemian was warmer than today the driving mechanism for this warmth was fundamentally different to present-day climate change, which is down to greenhouses gases. To find a warm period caused predominantly by conditions more similar to today, we need to go even further back in time.

 

The past 540 million years. Note the Eemian spike and the Miocene Optimum. Glen Fergus / wiki, CC BY-SA

 

As climate scientists, we’re particularly interested in the Miocene (around 23 to 5.3 million years ago), and in particular a spell known as the Miocene-Climate Optimum (11-17 million years ago). Around this time CO2 values (350-400ppm) were similar to today and it therefore potentially serves as an appropriate analogue for the future.

During the Optimum, those carbon dioxide concentrations were the predominant driver of climate change. Global average temperatures were 2 to 4˚C warmer than preindustrial values, sea level was around 20m higher and there was an expansion of tropical vegetation.

However, during the later Miocene period CO2 declined to below preindustrial levels, but global temperatures remained significantly warmer. What kept things warm, if not CO2? We still don’t know exactly – it may have been orbital shifts, the development of modern ocean circulation or even big geographical changes such as the Isthmus of Panama narrowing and eventually closing off – but it does mean direct comparison with the present day is problematic.

Currently orbital conditions are suitable to trigger the next glacial inception. We’re due another ice age. However, as pointed out in a recent study in Nature, there’s now so much carbon in the atmosphere the likelihood of this occurring is massively reduced over the next 100,000 years.

Emma Stone receives funding from the European Research Council.

Alex Farnsworth receives funding from the Natural Environmental Research Council (NERC).

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Gordon hopes for fresh start in 2016

Queensland MP Billy Gordon is hoping for a fresh start after dropping an extortion complaint against a Cairns grandmother.

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Christine Gibson, 50, was charged in September after police alleged she used an explicit picture of Mr Gordon to blackmail him.

But the case was dropped on Wednesday when police prosecutors offered no evidence to the charge.

“We decided on legal advice to withdraw the complaint on the basis of drawing a line in the sand and moving on,” Mr Gordon told ABC radio on Thursday.

“We made a conscious decision, particularly coming into the new year, to start afresh.”

The independent MP has rarely addressed his electorate or the media since allegations he sent numerous women explicit photos began to surface.

He admits scandals hindered his ability to represent Cook in 2015 but says he’ll be “staying out of the newspapers for the wrong reasons” this year.

“Going into 2016, we’ve made a commitment … to go out there on the front foot and really take the bull by the horns,” he said.

“Every bit of legislation that comes through the house this year has to come through me to some degree so, it’s going to be a really hectic year.”

The picture scandal was just one of many to bother Mr Gordon throughout the year.

He also faced allegations of domestic violence in NSW and Queensland but was cleared after police investigations.

Queensland Police also found there wasn’t enough evidence to lay charges over the alleged unsolicited explicit pictures.

Ms Gibson’s lawyer, Paul Richardson, had asked for details about the police investigation into the pictures for his client’s case but was told they could not be provided.

He told AAP Ms Gibson was relieved the charges had been dropped and looked forward to getting on with her life.

Opposition Leader Lawrence Springborg suggested Mr Gordon’s desire for a fresh start might not be that simple.

“I don’t think we should jump to any conclusions in thinking there won’t be any other personal issues around the Member for Cook,” Mr Springborg said.

“I mean time will tell in regards to that.”

Mr Springborg said Mr Gordon’s constituents will judge his actions at the next election.

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Oil spiral drives biodiesel producer under

Australia’s largest biodiesel producer has been forced into receivership as a result of the collapse in global oil prices and changes in federal government policy.

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Australian Renewable Fuels says it can no longer cope with the costs of producing its renewable fuel at a time when oil prices have slumped to under $US30 a barrel and dented demand for biodiesel.

While oil prices have plunged, prices for feedstock – renewable biological materials like animals fats and vegetable oils used to produce clean burning diesel – have jumped.

“The historical long term correlation between the barrel price of oil and the cost price of feedstock has broken down,” ARF directors said in a statement on Thursday.

“This has been exacerbated by the extent of the dramatic fall in the oil price and hence our selling price for biodiesel.”

The company needed to sell 48 million litres of biodiesel, which is safe to use in any diesel engine, to break even.

ARF sells biodiesel to fuel wholesalers and petrol distributors including Shell, BP, Greenfreight, Viva Energy Australia, Woolworths and Meredith Dairy.

It was developing a line of cheaper feedstock supplies from Asia, and had considered raising biodiesel sale prices, pursuing more exports to the United States, and cutting back on plant production to help keep the company afloat.

However these ideas were rejected by the company’s lenders, forcing it initially into voluntary administration before appointing KordaMentha as receivers.

ARF’s board also blamed its financial woes on federal government changes to biodiesel policies.

The government has scrapped its cleaner fuels tax grants scheme and provides subsidies for imported biodiesel.

“The continued and destabilising uncertainty of the federal government’s policy in regard to biodiesel over recent years had … increased the company’s financial reliance upon its debt providers,” ARF said.

ARF employs about 50 people at plants in Victoria, South Australia and Western Australia.

The company is maintaining operations for now while KordaMentha examines its books and searches for a buyer.

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Deng Thiak Adut delivers Australia Day address

Refugee lawyer and former child soldier Deng Thiak Adut says Australians should cherish the freedom from fear that comes with living in the country.

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Mr Adut arrived in Australia in 1998 from South Sudan, along with his brother, and went on to study law and work as a refugee lawyer in western Sydney, he told the audience at his Australia Day address for NSW.

Speaking on Thursday, he recalled a past speech by Sydney Lord Mayor Clover Moore, in which she said all non-Indigenous Australians are newcomers to the land.

“I wonder what the Gadigal people in 1788 thought as they watched the ships sailing, coming up to their harbour?” Mr Adut said.

“Did they realise that their civilisation was about to be uprooted?”

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Mr Adut recounted his life story – made famous in Western Sydney University TV advertisements, which he said he did to “emphasise how very lucky we are to enjoy freedom from fear, and how very unlucky are many.”

Born as one of eight children in a small village called Malek in South Sudan, Mr Adut was taken from his parents at the age of six and conscripted into the People’s Liberation Army in 1987.

Mr Adut told the audience at the Sydney Conservatorium of Music, which included Premier Mike Baird, he could barely comprehend the freedoms he had lost.

“I lost the freedom to read and write. I lost the freedom to sing children’s songs. I lost the right to be innocent. I lost the right to be a child.

“Instead I was taught to sing war songs.

“I was taught to love the death of others,” he said at the Australia Day Council of NSW’s annual address.

He said as a child soldier he was expected to “kill or be killed”, and reflected upon the small things Australians take for granted, such as education, plentiful food and clothing.

“I remember the deadened face and the gaunt skeletal body of one of my nephews lying on a corn sack,” he said.

“I saw too much abuse and death among my friends during the war.”

Denied an initiation into his tribe, Mr Adut said he did not know how it felt to belong until he received Australian citizenship many years later.

“The mark of inclusiveness was denied to me,” he said.

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He said Australia opened its doors to him and gave him the opportunity to educate himself.

“How lucky I became. How lucky is a person who receives an education in a free land and goes on to use it in daily life.”

He said he wondered what his fellow child soldier conscripts would have thought of him becoming a lawyer in Australia.

“I grieve for them. For them the freedom from fear was death – I was lucky,” he said.

After arriving in Australia, Mr Adut learned English and completed a TAFE degree in accounting before studying at Western Sydney University and Wollongong University.

He called on every migrant to cherish their new land, but to never forget their origins.

He said all new Australians must put trauma behind them and follow their dreams.

Settled Australians must be wary of allowing “local opportunists” to exploit emotions of fear and doubt.

“What makes this nation one to be proud of is the willingness of most in our communities to be accepting, tolerant, inclusive and welcoming,” he said.

Mr Baird said Mr Adut’s story was of a man who overcame every barrier before him.

“I don’t think any of us could imagine the challenges and obstacles that were put before Deng in his life,” Mr Baird said.

“But, in those challenges, he not only overcame, he found himself here as part of this great country, and he is determined to give back.”