[One-Minute World News] from [BBC NEWS]
[Science & Environment]
Page last updated at 23:53 GMT, Monday, 11 January 2010
By Jonathan Amos
Science correspondent, BBC News
Arctic tern's epic journey mapped
The Arctic tern's extraordinary pole-to-pole migration has been detailed by an international team of scientists.
The researchers fitted the birds with tiny tracking devices to see precisely which routes the animals took on their 70,000km (43,000 miles) round trip.
The study reveals they fly down either the African or Brazilian coasts but then return in an "S"-shaped path up the middle of the Atlantic Ocean.
The long-distance adventure is described in the US journal PNAS.
"From ringing, we knew where the Arctic tern travelled," said Carsten Egevang of the Greenland Institute of Natural Resources.
{{After setting out (---) the birds pause in the North Atlantic (---) to feed. Going home (---), they follow the winds
> Total distance travelled 70,900km
> On southbound leg: 34,600km
> Daily progress south: 330km
> On northbound leg: 25,700km
> Daily progress north: 520km
> Within Winter grounds: 10,900km}
"The new thing is that we've now been able to track the bird during a full year of migration, all the way from the breeding grounds to the wintering grounds and back again."
The avian world is known for its great migrations.
Albatrosses, godwits, and sooty shearwaters all undertake epic journeys. But none can quite match the Arctic tern's colossal trip.
Starting in August and September, this small bird - which weighs little more than 100g (3.5oz) - will head away from Greenland with the intention of getting to the Weddell Sea, on the shores of Antarctica.
It will spend about four or five months in the deep south before heading back to the far north, arriving home in May or June.
A team from Greenland, Denmark, the US, the UK and Iceland attached small (1.4g/0.05oz) "geolocators" to the animals to find out exactly where they went on this polar round trip.
The devices record light intensity. This gives an estimate of the local day length, and the times of sunrise and sunset; and from this information it is possible to work out a geographical position of the birds.
The geolocators were provided by the British Antarctic Survey (BAS).
"The use of these devices on seabirds is not only revolutionising our understanding of migration patterns, but the resulting data on distribution also help address the requirement to identify important biological hotspots," said Richard Phillips from BAS, a co-author of the PNAS paper.
{With such a small bird, the trackers also need to be tiny}
The first surprise is that the terns do not make straight for the Antarctic when they leave the Arctic, but make a lengthy stop-over in the middle of the North Atlantic, about 1,000km (620 miles) north of the Azores.
Here, they feed on zooplankton and fish to fuel themselves for the long journey ahead.
"We were able to compare biological productivity in the ocean from satellite imagery and we could see a high productive area that the birds will spend time in," said Mr Egevang.
"Even more importantly, it's the last high productive area before they enter tropical waters where we know productivity is low."
{{THE LONG DISTANCE FLIER}
> Scientific name: Sterna paradisaea
> Average wingspan of 75-85cm
> Breeds in Arctic and sub-Arctic
> Lays eggs in small ground scrape
> Feeds on fish and crustaceans
> Birds live more than 30 years}
The birds then head south along the coast of western Europe and western Africa before making a choice, either to continue hugging Africa or sweep across the Atlantic from the Cape Verde Islands to continue the journey along the Brazilian coast.
About half the birds that were tracked decided to take the South American path. It is not clear why, but the researchers believe wind might make either route seem favourable to the terns.
After spending their northern winter months in Antarctic waters, the terns then fly back towards the Arctic.
But rather than retracing their southward flight paths, the birds follow a gigantic "S" pattern up the middle of the Atlantic Ocean.
"This is completely new knowledge," Mr Egevang told BBC News.
"They make a detour of several thousand km but once we start comparing the route to the prevailing wind system, it makes perfect sense - moving in a counter-clockwise direction in the Southern Hemisphere, and clockwise in the Northern Hemisphere.
"It's just more energy-efficient for them to do that even though they are travelling several thousand more km than if they flew in a straight line."
[Science & Environment]
Page last updated at 16:57 GMT, Monday, 11 January 2010
By Jason Palmer
Science and technology reporter, BBC News
Chemical computer that mimics neurons to be created
A promising push toward a novel, biologically-inspired "chemical computer" has begun as part of an international collaboration.
The "wet computer" incorporates several recently discovered properties of chemical systems that can be hijacked to engineer computing power.
The team's approach mimics some of the actions of neurons in the brain.
The 1.8m-euro (£1.6m) project will run for three years, funded by an EU emerging technologies programme.
The programme has identified biologically-inspired computing as particularly important, having recently funded several such projects.
What distinguishes the current project is that it will make use of stable "cells" featuring a coating that forms spontaneously, similar to the walls of our own cells, and uses chemistry to accomplish the signal processing similar to that of our own neurons.
The goal is not to make a better computer than conventional ones, said project collaborator Klaus-Peter Zauner of the University of Southampton, but rather to be able to compute in new environments.
{{If one day we want to construct computers of similar power and complexity to the human brain, my bet would be on some form of chemical or molecular computing}
Frantisek Stepanek, Institute of Chemical Technology, Prague}
"The type of wet information technology we are working towards will not find its near-term application in running business software," Dr Zauner told BBC News.
"But it will open up application domains where current IT does not offer any solutions - controlling molecular robots, fine-grained control of chemical assembly, and intelligent drugs that process the chemical signals of the human body and act according to the local biochemical state of the cell."
Lipids and liquids
The group's approach hinges on two critical ideas.
First, individual "cells" are surrounded by a wall made up of so-called lipids that spontaneously encapsulate the liquid innards of the cell.
Recent work has shown that when two such lipid layers encounter each other as the cells come into contact, a protein can form a passage between them, allowing chemical signalling molecules to pass.
Second, the cells' interiors will play host to what is known as a Belousov-Zhabotinsky or B-Z chemical reaction. Simply put, reactions of this type can be initiated by changing the concentration of the element bromine by a certain threshold amount.
The reactions are unusual for a number of reasons.
But for the computing application, what is important is that after the arrival of a chemical signal to start it, the cell enters a "refractory period" during which further chemical signals do not influence the reaction.
That keeps a signal from propagating unchecked through any connected cells.
Such self-contained systems that react under their own chemical power to a stimulus above a threshold have an analogue in nature: neurons.
{Each neuron in our brains can be viewed as a chemical computer}
"Every neuron is like a molecular computer; ours is a very crude abstraction of what neurons do," said Dr Zauner.
"But the essence of neurons is the capability to get 'excited'; it can re-form an input signal and has its own energy supply so it can fire out a new signal."
This propagation of a chemical signal - along with the "refractory period" that keeps it contained within a given cell - means the cells can form networks that function like the brain.
'Real chance'
Frantisek Stepanek, a chemical computing researcher at the Institute of Chemical Technology Prague in the Czech Republic, said the pairing of the two ideas was promising.
"If one day we want to construct computers of similar power and complexity to the human brain, my bet would be on some form of chemical or molecular computing," he told BBC News.
"I think this project stands a real chance of bringing chemical computing from the concept stage to a practical demonstration of a functional prototype."
For its part, the team is already hard at work proving the idea will work.
"Officially the project doesn't start until the first of February," said Dr Zauner, "but we were so curious about it we already sent some lipids to our collaborators in Poland - they've already shown the lipid layers are stable."
[Science & Environment]
Page last updated at 23:53 GMT, Monday, 11 January 2010
By Jonathan Amos
Science correspondent, BBC News
Arctic tern's epic journey mapped
The Arctic tern's extraordinary pole-to-pole migration has been detailed by an international team of scientists.
The researchers fitted the birds with tiny tracking devices to see precisely which routes the animals took on their 70,000km (43,000 miles) round trip.
The study reveals they fly down either the African or Brazilian coasts but then return in an "S"-shaped path up the middle of the Atlantic Ocean.
The long-distance adventure is described in the US journal PNAS.
"From ringing, we knew where the Arctic tern travelled," said Carsten Egevang of the Greenland Institute of Natural Resources.
{{After setting out (---) the birds pause in the North Atlantic (---) to feed. Going home (---), they follow the winds
> Total distance travelled 70,900km
> On southbound leg: 34,600km
> Daily progress south: 330km
> On northbound leg: 25,700km
> Daily progress north: 520km
> Within Winter grounds: 10,900km}
"The new thing is that we've now been able to track the bird during a full year of migration, all the way from the breeding grounds to the wintering grounds and back again."
The avian world is known for its great migrations.
Albatrosses, godwits, and sooty shearwaters all undertake epic journeys. But none can quite match the Arctic tern's colossal trip.
Starting in August and September, this small bird - which weighs little more than 100g (3.5oz) - will head away from Greenland with the intention of getting to the Weddell Sea, on the shores of Antarctica.
It will spend about four or five months in the deep south before heading back to the far north, arriving home in May or June.
A team from Greenland, Denmark, the US, the UK and Iceland attached small (1.4g/0.05oz) "geolocators" to the animals to find out exactly where they went on this polar round trip.
The devices record light intensity. This gives an estimate of the local day length, and the times of sunrise and sunset; and from this information it is possible to work out a geographical position of the birds.
The geolocators were provided by the British Antarctic Survey (BAS).
"The use of these devices on seabirds is not only revolutionising our understanding of migration patterns, but the resulting data on distribution also help address the requirement to identify important biological hotspots," said Richard Phillips from BAS, a co-author of the PNAS paper.
{With such a small bird, the trackers also need to be tiny}
The first surprise is that the terns do not make straight for the Antarctic when they leave the Arctic, but make a lengthy stop-over in the middle of the North Atlantic, about 1,000km (620 miles) north of the Azores.
Here, they feed on zooplankton and fish to fuel themselves for the long journey ahead.
"We were able to compare biological productivity in the ocean from satellite imagery and we could see a high productive area that the birds will spend time in," said Mr Egevang.
"Even more importantly, it's the last high productive area before they enter tropical waters where we know productivity is low."
{{THE LONG DISTANCE FLIER}
> Scientific name: Sterna paradisaea
> Average wingspan of 75-85cm
> Breeds in Arctic and sub-Arctic
> Lays eggs in small ground scrape
> Feeds on fish and crustaceans
> Birds live more than 30 years}
The birds then head south along the coast of western Europe and western Africa before making a choice, either to continue hugging Africa or sweep across the Atlantic from the Cape Verde Islands to continue the journey along the Brazilian coast.
About half the birds that were tracked decided to take the South American path. It is not clear why, but the researchers believe wind might make either route seem favourable to the terns.
After spending their northern winter months in Antarctic waters, the terns then fly back towards the Arctic.
But rather than retracing their southward flight paths, the birds follow a gigantic "S" pattern up the middle of the Atlantic Ocean.
"This is completely new knowledge," Mr Egevang told BBC News.
"They make a detour of several thousand km but once we start comparing the route to the prevailing wind system, it makes perfect sense - moving in a counter-clockwise direction in the Southern Hemisphere, and clockwise in the Northern Hemisphere.
"It's just more energy-efficient for them to do that even though they are travelling several thousand more km than if they flew in a straight line."
[Science & Environment]
Page last updated at 16:57 GMT, Monday, 11 January 2010
By Jason Palmer
Science and technology reporter, BBC News
Chemical computer that mimics neurons to be created
A promising push toward a novel, biologically-inspired "chemical computer" has begun as part of an international collaboration.
The "wet computer" incorporates several recently discovered properties of chemical systems that can be hijacked to engineer computing power.
The team's approach mimics some of the actions of neurons in the brain.
The 1.8m-euro (£1.6m) project will run for three years, funded by an EU emerging technologies programme.
The programme has identified biologically-inspired computing as particularly important, having recently funded several such projects.
What distinguishes the current project is that it will make use of stable "cells" featuring a coating that forms spontaneously, similar to the walls of our own cells, and uses chemistry to accomplish the signal processing similar to that of our own neurons.
The goal is not to make a better computer than conventional ones, said project collaborator Klaus-Peter Zauner of the University of Southampton, but rather to be able to compute in new environments.
{{If one day we want to construct computers of similar power and complexity to the human brain, my bet would be on some form of chemical or molecular computing}
Frantisek Stepanek, Institute of Chemical Technology, Prague}
"The type of wet information technology we are working towards will not find its near-term application in running business software," Dr Zauner told BBC News.
"But it will open up application domains where current IT does not offer any solutions - controlling molecular robots, fine-grained control of chemical assembly, and intelligent drugs that process the chemical signals of the human body and act according to the local biochemical state of the cell."
Lipids and liquids
The group's approach hinges on two critical ideas.
First, individual "cells" are surrounded by a wall made up of so-called lipids that spontaneously encapsulate the liquid innards of the cell.
Recent work has shown that when two such lipid layers encounter each other as the cells come into contact, a protein can form a passage between them, allowing chemical signalling molecules to pass.
Second, the cells' interiors will play host to what is known as a Belousov-Zhabotinsky or B-Z chemical reaction. Simply put, reactions of this type can be initiated by changing the concentration of the element bromine by a certain threshold amount.
The reactions are unusual for a number of reasons.
But for the computing application, what is important is that after the arrival of a chemical signal to start it, the cell enters a "refractory period" during which further chemical signals do not influence the reaction.
That keeps a signal from propagating unchecked through any connected cells.
Such self-contained systems that react under their own chemical power to a stimulus above a threshold have an analogue in nature: neurons.
{Each neuron in our brains can be viewed as a chemical computer}
"Every neuron is like a molecular computer; ours is a very crude abstraction of what neurons do," said Dr Zauner.
"But the essence of neurons is the capability to get 'excited'; it can re-form an input signal and has its own energy supply so it can fire out a new signal."
This propagation of a chemical signal - along with the "refractory period" that keeps it contained within a given cell - means the cells can form networks that function like the brain.
'Real chance'
Frantisek Stepanek, a chemical computing researcher at the Institute of Chemical Technology Prague in the Czech Republic, said the pairing of the two ideas was promising.
"If one day we want to construct computers of similar power and complexity to the human brain, my bet would be on some form of chemical or molecular computing," he told BBC News.
"I think this project stands a real chance of bringing chemical computing from the concept stage to a practical demonstration of a functional prototype."
For its part, the team is already hard at work proving the idea will work.
"Officially the project doesn't start until the first of February," said Dr Zauner, "but we were so curious about it we already sent some lipids to our collaborators in Poland - they've already shown the lipid layers are stable."
※コメント投稿者のブログIDはブログ作成者のみに通知されます