New image shows a haunting comet landscape

Comet 67P/Churyumov-Gerasimenko as seen by the Rosetta spacecraft on September 22, 2014. Amateur astronomer Jacint Roger Perez, from Spain, processed this image, which is via ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; J. Roger.

The European Space Agency (ESA) has been celebrating its Rosetta spacecraft, which was the first (and still only) craft to give us extremely close-up images of a comet. Rosetta ended its mission to comet 67P/Churyumov-Gerasimenko on September 30, 2016, with a controlled impact on the comet’s surface. Prior to that, it had monitored cometary evolution – in a way never seen before – for about a year before and after 67P came closest to the sun in August, 2015. On October 1, 2018, ESA released this image of the comet. Haunting, isn’t it? It shows a portion of the comet as viewed by Rosetta only one-and-a-half months after Rosetta began orbiting 67P in September, 2014. At the time of the image above, the spacecraft was just over 16 miles (26.2 km) from the comet’s surface. Amateur astronomer Jacint Roger Perez, from Spain, selected and processed this view by combining three images taken in different wavelengths by the OSIRIS narrow-angle camera on Rosetta. ESA said in a statement:

Seen in the center and left of the frame is Seth, one of the geological regions on the larger of the two comet lobes, which declines towards the smoother Hapi region on the comet’s ‘neck’ that connects the two lobes. The landscape in the background reveals hints of the Babi and Aker regions, both located on the large lobe of 67P/C-G …

The sharp profile in the lower part of the image shows the Aswan cliff, a 134 m-high scarp separating the Seth and Hapi regions. Observations performed by Rosetta not long before the comet’s perihelion, which took place on 13 August 2015, revealed that a chunk of this cliff had collapsed – a consequence of increased activity as the comet drew closer to the Sun along its orbit.

Before Rosetta, no one knew comets looked like this. Rosetta followed comet 67P/ Churyumov-Gerasimenko to its closest point to the sun and beyond. As the comet neared the sun, the spacecraft’s cameras saw jets erupting from comet. Image via ESA’s Rosetta spacecraft/ NASA.

As the images rolled in from Rosetta, scientists gave names to the various regions on the surface of 67P, to aid in their discussions. Image via Astronomy & Astrophysics.

ESA launched the Rosetta spacecraft in 2004. The craft took 10 Earth-years to reach the comet, ultimately making six orbits around the sun. Its journey included three Earth flybys, a Mars flyby, and two asteroid encounters. The craft endured 31 months in deep-space hibernation on the most distant leg of its journey, before waking up in January 2014 and finally arriving at the comet in August 2014.

By the way, ESA invites you to:

Explore the full mission image archive yourself at and let us know what hidden treasures you find via @esascience.

View larger. | Compilation of the brightest outbursts seen at Comet 67P/Churyumov–Gerasimenko by Rosetta spacecraft between July and September 2015, via ESA.

Bottom line: Amateur astronomer Jacint Roger Perez of Spain processed this Rosetta spacecraft view of comet 67P/Churyumov-Gerasimenko.

from EarthSky https://ift.tt/2NVQrEh

Comet 67P/Churyumov-Gerasimenko as seen by the Rosetta spacecraft on September 22, 2014. Amateur astronomer Jacint Roger Perez, from Spain, processed this image, which is via ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; J. Roger.

The European Space Agency (ESA) has been celebrating its Rosetta spacecraft, which was the first (and still only) craft to give us extremely close-up images of a comet. Rosetta ended its mission to comet 67P/Churyumov-Gerasimenko on September 30, 2016, with a controlled impact on the comet’s surface. Prior to that, it had monitored cometary evolution – in a way never seen before – for about a year before and after 67P came closest to the sun in August, 2015. On October 1, 2018, ESA released this image of the comet. Haunting, isn’t it? It shows a portion of the comet as viewed by Rosetta only one-and-a-half months after Rosetta began orbiting 67P in September, 2014. At the time of the image above, the spacecraft was just over 16 miles (26.2 km) from the comet’s surface. Amateur astronomer Jacint Roger Perez, from Spain, selected and processed this view by combining three images taken in different wavelengths by the OSIRIS narrow-angle camera on Rosetta. ESA said in a statement:

Seen in the center and left of the frame is Seth, one of the geological regions on the larger of the two comet lobes, which declines towards the smoother Hapi region on the comet’s ‘neck’ that connects the two lobes. The landscape in the background reveals hints of the Babi and Aker regions, both located on the large lobe of 67P/C-G …

The sharp profile in the lower part of the image shows the Aswan cliff, a 134 m-high scarp separating the Seth and Hapi regions. Observations performed by Rosetta not long before the comet’s perihelion, which took place on 13 August 2015, revealed that a chunk of this cliff had collapsed – a consequence of increased activity as the comet drew closer to the Sun along its orbit.

Before Rosetta, no one knew comets looked like this. Rosetta followed comet 67P/ Churyumov-Gerasimenko to its closest point to the sun and beyond. As the comet neared the sun, the spacecraft’s cameras saw jets erupting from comet. Image via ESA’s Rosetta spacecraft/ NASA.

As the images rolled in from Rosetta, scientists gave names to the various regions on the surface of 67P, to aid in their discussions. Image via Astronomy & Astrophysics.

ESA launched the Rosetta spacecraft in 2004. The craft took 10 Earth-years to reach the comet, ultimately making six orbits around the sun. Its journey included three Earth flybys, a Mars flyby, and two asteroid encounters. The craft endured 31 months in deep-space hibernation on the most distant leg of its journey, before waking up in January 2014 and finally arriving at the comet in August 2014.

By the way, ESA invites you to:

Explore the full mission image archive yourself at and let us know what hidden treasures you find via @esascience.

View larger. | Compilation of the brightest outbursts seen at Comet 67P/Churyumov–Gerasimenko by Rosetta spacecraft between July and September 2015, via ESA.

Bottom line: Amateur astronomer Jacint Roger Perez of Spain processed this Rosetta spacecraft view of comet 67P/Churyumov-Gerasimenko.

from EarthSky https://ift.tt/2NVQrEh

Nobel Prize 2018: How Allison and Honjo turned immune cells against cancer

Using a patient’s immune system to fight cancer seems like a gloriously simple solution to a horribly complex disease. The reality is far harder than it sounds, but this type of treatment, called immunotherapy, has begun transforming the way we treat certain cancers.

Today, two scientists who laid the ground work for a suite of new cancer drugs have been recognised.

Dr James Allison, from The University of Texas MD Anderson Cancer Center, and Professor Tasuku Honjo, from Kyoto University, have been awarded the Nobel Prize for Physiology or Medicine “for their discovery of cancer therapy by inhibition of negative immune regulation.”

But what does this mean?

The duo’s discoveries have revolutionised our understanding of how the immune system sees cancer. And at the heart of this revolution is a tiny but extremely powerful immune cell called a T cell. 

The mighty T cell

T cells live in our bodies and protect us from foreign invaders, such as bacteria and viruses. And, under the right conditions, they can also destroy cancer cells.

T cells circulate our bodies scanning for molecular flags that signal ‘danger’. And they’re constantly making decisions about how to react to what they’re inspecting. They can either do nothing, or alert other immune cells to start an attack.

T cells carry an array of molecular machinery on their surface that helps them make this choice. And thanks to Allison and Honjo, we now know the inner workings of two key components – called CTLA-4 and PD-1 – make T cells tick, or rather, stay quiet.

Targets for immune-boosting drugs: Allison’s work on CTLA-4

In 1996, Allison and his team found that CTLA-4 works like a silencing switch on T cells – preventing them from assembling an army of supporting immune cells to attack foreign invaders. And in landmark work, the team showed early signs of how this knowledge could transform cancer treatment. They gave mice with cancer a molecule that blocks CTLA-4, freeing T cells to build the immune response – the tumours started to shrink.

Dr Sergio Quezada, a Cancer Research UK-funded immunologist from University College London, worked in Allison’s lab shortly after this seminal work was unveiled. 

“Allison was trying to understand what actually makes a T cells active and during these investigations he worked out how T cells were made inactive,” he says.

According to Quezada, Allison realised immediately that this knowledge could inform new cancer treatments. He started talking to pharmaceutical companies and spread the word that CTLA-4 could be a promising new drug target. 

“This Nobel Prize really shows that basic science can have a huge impact on medicine,” says Quezada. “He was always out at conferences, but he let the data do the talking.”

Targets for immune-boosting drugs: Honjo’s work on PD-1

The surface of T cells now seemed like the best place to look for new molecules that controlled these immune cells. Only a few years later Professor Tasuku Honjo and his team identified another molecule that influences T cell activity, called PD-1.

PD-1 sticks to a molecule on cancer cells called PD-L1. This interaction causes the immune cells to ignore the tumour cell. And drugs stopping this molecular ‘handshake’ help reveal tumour cells to the immune system, allowing T cells to attack and kill the cancer cells.

Watch this video to see how these drugs work:

 

Both CTLA-4 and PD-1 can be manipulated by drugs called checkpoint inhibitors. If we didn’t know how these molecules worked then the immune-boosting drugs of today, and the future, would never exist.

Read more: New immunotherapy drugs hit the headlines – how do they work?

Where are we now?

Thanks to these two scientists, and the teams of researchers involved, many companies are now developing drugs that block CTLA-4, PD-1 and PD-L1. And the hunt for other similar molecules continues.

Ipilimumab (Yervoy) was the first of its kind to emerge from Allison’s discovery.

It’s designed to block CTLA-4 so that the T cells stay switched on, freeing them to coordinate an attack on cancer cells.

Pembrolizumab (Keytruda) and Nivolumab (Opdivo) target the PD-1 molecules on the surface of T cells. And in doing so, it releases the ‘brakes’ on the immune cells so they can find and kill cancer cells.

In many cases these drugs are still being tested in clinical trials. But for some advanced cancers they have already saved lives.

Immunotherapy is literally a life-saver: I’m here today thanks to drugs developed from these researchers’ work.

 

– Jolene Dyke, melanoma patient

Jolene Dyke, 31, was diagnosed with melanoma in her teens. By her twenties, the disease had spread to her lungs, brain and bowel, and she was told she would have months to live.

Thanks to immunotherapy her cancer is now stable. And she offers her tribute to all the scientists behind today’s prize-winning discoveries. “Immunotherapy is literally a life-saver: I’m here today thanks to drugs developed from these researchers’ work. It’s just fantastic that they’ve been recognised with a Nobel Prize.”

Jolene says she hopes this prize inspires researchers to redouble their efforts to uncover the next generation of treatments.

What’s left to do?

Despite great progress, responses to immunotherapy like Jolene’s are the exception, rather than the rule. But Quezada is feeling good about the future. “If you think CTLA-4 and PD-1 have revolutionised the way we think about cancer therapy in the last eight years, imagine what the drugs in the pipeline could do,” he says. “There’s a huge amount of potential.”

Now, Quezada says, scientists must build their understanding of how these drugs work in patients, either alone or together, so we know the best ways to boost response rates.

“That’s why we need to keep funding research in this area and engaging patients, so we can understand why drugs work and more importantly what’s going on when they don’t work, and how can we fix that.”

While many were looking at the inner workings of cancer cells in the hunt for new drugs, these immunologists asked how the body sees cancer.

And in doing so, Allison, Honjo and their teams thrust the immune system into the spotlight as a powerful tool in treating cancer.

Gabi

from Cancer Research UK – Science blog https://ift.tt/2y8i6qS

Using a patient’s immune system to fight cancer seems like a gloriously simple solution to a horribly complex disease. The reality is far harder than it sounds, but this type of treatment, called immunotherapy, has begun transforming the way we treat certain cancers.

Today, two scientists who laid the ground work for a suite of new cancer drugs have been recognised.

Dr James Allison, from The University of Texas MD Anderson Cancer Center, and Professor Tasuku Honjo, from Kyoto University, have been awarded the Nobel Prize for Physiology or Medicine “for their discovery of cancer therapy by inhibition of negative immune regulation.”

But what does this mean?

The duo’s discoveries have revolutionised our understanding of how the immune system sees cancer. And at the heart of this revolution is a tiny but extremely powerful immune cell called a T cell. 

The mighty T cell

T cells live in our bodies and protect us from foreign invaders, such as bacteria and viruses. And, under the right conditions, they can also destroy cancer cells.

T cells circulate our bodies scanning for molecular flags that signal ‘danger’. And they’re constantly making decisions about how to react to what they’re inspecting. They can either do nothing, or alert other immune cells to start an attack.

T cells carry an array of molecular machinery on their surface that helps them make this choice. And thanks to Allison and Honjo, we now know the inner workings of two key components – called CTLA-4 and PD-1 – make T cells tick, or rather, stay quiet.

Targets for immune-boosting drugs: Allison’s work on CTLA-4

In 1996, Allison and his team found that CTLA-4 works like a silencing switch on T cells – preventing them from assembling an army of supporting immune cells to attack foreign invaders. And in landmark work, the team showed early signs of how this knowledge could transform cancer treatment. They gave mice with cancer a molecule that blocks CTLA-4, freeing T cells to build the immune response – the tumours started to shrink.

Dr Sergio Quezada, a Cancer Research UK-funded immunologist from University College London, worked in Allison’s lab shortly after this seminal work was unveiled. 

“Allison was trying to understand what actually makes a T cells active and during these investigations he worked out how T cells were made inactive,” he says.

According to Quezada, Allison realised immediately that this knowledge could inform new cancer treatments. He started talking to pharmaceutical companies and spread the word that CTLA-4 could be a promising new drug target. 

“This Nobel Prize really shows that basic science can have a huge impact on medicine,” says Quezada. “He was always out at conferences, but he let the data do the talking.”

Targets for immune-boosting drugs: Honjo’s work on PD-1

The surface of T cells now seemed like the best place to look for new molecules that controlled these immune cells. Only a few years later Professor Tasuku Honjo and his team identified another molecule that influences T cell activity, called PD-1.

PD-1 sticks to a molecule on cancer cells called PD-L1. This interaction causes the immune cells to ignore the tumour cell. And drugs stopping this molecular ‘handshake’ help reveal tumour cells to the immune system, allowing T cells to attack and kill the cancer cells.

Watch this video to see how these drugs work:

 

Both CTLA-4 and PD-1 can be manipulated by drugs called checkpoint inhibitors. If we didn’t know how these molecules worked then the immune-boosting drugs of today, and the future, would never exist.

Read more: New immunotherapy drugs hit the headlines – how do they work?

Where are we now?

Thanks to these two scientists, and the teams of researchers involved, many companies are now developing drugs that block CTLA-4, PD-1 and PD-L1. And the hunt for other similar molecules continues.

Ipilimumab (Yervoy) was the first of its kind to emerge from Allison’s discovery.

It’s designed to block CTLA-4 so that the T cells stay switched on, freeing them to coordinate an attack on cancer cells.

Pembrolizumab (Keytruda) and Nivolumab (Opdivo) target the PD-1 molecules on the surface of T cells. And in doing so, it releases the ‘brakes’ on the immune cells so they can find and kill cancer cells.

In many cases these drugs are still being tested in clinical trials. But for some advanced cancers they have already saved lives.

Immunotherapy is literally a life-saver: I’m here today thanks to drugs developed from these researchers’ work.

 

– Jolene Dyke, melanoma patient

Jolene Dyke, 31, was diagnosed with melanoma in her teens. By her twenties, the disease had spread to her lungs, brain and bowel, and she was told she would have months to live.

Thanks to immunotherapy her cancer is now stable. And she offers her tribute to all the scientists behind today’s prize-winning discoveries. “Immunotherapy is literally a life-saver: I’m here today thanks to drugs developed from these researchers’ work. It’s just fantastic that they’ve been recognised with a Nobel Prize.”

Jolene says she hopes this prize inspires researchers to redouble their efforts to uncover the next generation of treatments.

What’s left to do?

Despite great progress, responses to immunotherapy like Jolene’s are the exception, rather than the rule. But Quezada is feeling good about the future. “If you think CTLA-4 and PD-1 have revolutionised the way we think about cancer therapy in the last eight years, imagine what the drugs in the pipeline could do,” he says. “There’s a huge amount of potential.”

Now, Quezada says, scientists must build their understanding of how these drugs work in patients, either alone or together, so we know the best ways to boost response rates.

“That’s why we need to keep funding research in this area and engaging patients, so we can understand why drugs work and more importantly what’s going on when they don’t work, and how can we fix that.”

While many were looking at the inner workings of cancer cells in the hunt for new drugs, these immunologists asked how the body sees cancer.

And in doing so, Allison, Honjo and their teams thrust the immune system into the spotlight as a powerful tool in treating cancer.

Gabi

from Cancer Research UK – Science blog https://ift.tt/2y8i6qS

Origami-inspired habitats for the moon and Mars

This origami entrance tunnel prototype was deployed and tested in extreme conditions on April 20, 2018 during the EuroMoonMars 2018 simulation at ESA–ESTEC. Image via Anna Sitnikova/ EuroPlanet.

Human habitation of the moon and Mars might still seem like a far-off dream, but visionaries are already taking incremental steps toward that goal. One such initiative comes from the EuroMoonMars project, which has just completed field tests of a prototype for human habitats and research stations, whose design is based on Japanese origami*. The prototype uses a combination of origami and smart textiles for its futuristic concept – which could one day become reality. Anna Sitnikova presented the concept at last month’s European Planetary Science Congress 2018 (September 16-21, 2018) in Berlin.

The structures are designed specifically for unearthly environments such as those found on the moon and Mars. As explained by Sitnikova:

Origami structures made of textiles can be unfolded into a myriad of different shapes. They are lightweight. They can be easily deployed and re-used in different configurations and sizes for flexible spatial usage. Structures remain functional in changing circumstances, thereby extending their useable life-span.

The architect studio Samira Boon has created woven self-supported origami structures from single sheets of fabric and woven self supportive arcs. Image via the textile architect studio Samira Boon, which is participating in the project.

The origami structure is combined with digital weaving processes to sculpt complex forms. The designers say these forms are compact to transport and easy to deploy through inflatable, pop-up or robotic mechanisms. They say they’re ideally suited for environments with little or no atmosphere, like the moon and Mars. And they claim the structures can also reduce the risk of meteorite damage by using angled facets so that incoming micrometeorites are less likely hit surfaces at 90 degrees. This dissipates the energy of potential impacts and significantly reduces the risk of penetration.

What’s more, the shape-shifting material has solar panels embedded in it which can follow the sun throughout the day.

And it has transparent and opaque facets can change direction to alter internal lighting and climate conditions in the habitats.

The first test of a prototype entrance tunnel were conducted in April 2018 during the EuroMoonMars simulation at the European Space Agency’s ESTEC facility; ESTEC is another partner in the project. The next tests, scheduled for 2019, will go farther. In June, the IGLUNA project, led by the Swiss Space Center, will conduct tests of an origami habitat in the glacier above Zermatt in Switzerland. In September, the team will travel to Iceland to test inside a lava-tube cave system. According to Sitnikova:

We’ve just returned from a scouting trip and have selected the cave systems of Stefanshellir and Surtshellir, which has large galleries and a very elaborate tunnel system. We are provisionally looking at setting up a small habitat, implementing knowledge from previous demonstrations of our origami tunnel and woven domes.

Origami for space architecture promotes cross-disciplinary approaches and applications, providing state-of-the-art production and design methods. Habitats enhanced by such structures are temporal and alive as they are able to transform and redefine themselves in resonance with human and environmental factors.

A complex woven and self-supported origami dome created from a single sheet of fabric and a woven self supportive arc. Image via Samira Boon.

The freeform Origami Software, by collaborator Tomohiro Tachi, allows the team to sculpt or generate complex origami forms while altering the crease pattern of the model. Image via Tomohiro Tachi.

The next major objective of the project is to design a self-deployable origami habitat. Such “smart” habitats will be needed when a habitat or base is eventually set up on the moon – and later, Mars.

*Note: Origami is a popular Japanese art of paper folding, with the goal to transform a flat square sheet of paper into a finished sculpture through various folding and sculpting techniques, such as the ever-popular paper crane. Although most often associated with Japanese culture, there have also been similar paper folding traditions in Europe and China.

Bottom line: Origami, the elegant Japanese art of paper folding, is now being used in futuristic designs for human habitats on the moon and Mars. It’s an excellent example of blending old techniques with new ideas, and shows the kinds of creative thinking needed if humans are ever to inhabit other worlds.

Source: Self Deployable Origami for MoonMars Architecture

Via Europlanet

from EarthSky https://ift.tt/2ItQykr

This origami entrance tunnel prototype was deployed and tested in extreme conditions on April 20, 2018 during the EuroMoonMars 2018 simulation at ESA–ESTEC. Image via Anna Sitnikova/ EuroPlanet.

Human habitation of the moon and Mars might still seem like a far-off dream, but visionaries are already taking incremental steps toward that goal. One such initiative comes from the EuroMoonMars project, which has just completed field tests of a prototype for human habitats and research stations, whose design is based on Japanese origami*. The prototype uses a combination of origami and smart textiles for its futuristic concept – which could one day become reality. Anna Sitnikova presented the concept at last month’s European Planetary Science Congress 2018 (September 16-21, 2018) in Berlin.

The structures are designed specifically for unearthly environments such as those found on the moon and Mars. As explained by Sitnikova:

Origami structures made of textiles can be unfolded into a myriad of different shapes. They are lightweight. They can be easily deployed and re-used in different configurations and sizes for flexible spatial usage. Structures remain functional in changing circumstances, thereby extending their useable life-span.

The architect studio Samira Boon has created woven self-supported origami structures from single sheets of fabric and woven self supportive arcs. Image via the textile architect studio Samira Boon, which is participating in the project.

The origami structure is combined with digital weaving processes to sculpt complex forms. The designers say these forms are compact to transport and easy to deploy through inflatable, pop-up or robotic mechanisms. They say they’re ideally suited for environments with little or no atmosphere, like the moon and Mars. And they claim the structures can also reduce the risk of meteorite damage by using angled facets so that incoming micrometeorites are less likely hit surfaces at 90 degrees. This dissipates the energy of potential impacts and significantly reduces the risk of penetration.

What’s more, the shape-shifting material has solar panels embedded in it which can follow the sun throughout the day.

And it has transparent and opaque facets can change direction to alter internal lighting and climate conditions in the habitats.

The first test of a prototype entrance tunnel were conducted in April 2018 during the EuroMoonMars simulation at the European Space Agency’s ESTEC facility; ESTEC is another partner in the project. The next tests, scheduled for 2019, will go farther. In June, the IGLUNA project, led by the Swiss Space Center, will conduct tests of an origami habitat in the glacier above Zermatt in Switzerland. In September, the team will travel to Iceland to test inside a lava-tube cave system. According to Sitnikova:

We’ve just returned from a scouting trip and have selected the cave systems of Stefanshellir and Surtshellir, which has large galleries and a very elaborate tunnel system. We are provisionally looking at setting up a small habitat, implementing knowledge from previous demonstrations of our origami tunnel and woven domes.

Origami for space architecture promotes cross-disciplinary approaches and applications, providing state-of-the-art production and design methods. Habitats enhanced by such structures are temporal and alive as they are able to transform and redefine themselves in resonance with human and environmental factors.

A complex woven and self-supported origami dome created from a single sheet of fabric and a woven self supportive arc. Image via Samira Boon.

The freeform Origami Software, by collaborator Tomohiro Tachi, allows the team to sculpt or generate complex origami forms while altering the crease pattern of the model. Image via Tomohiro Tachi.

The next major objective of the project is to design a self-deployable origami habitat. Such “smart” habitats will be needed when a habitat or base is eventually set up on the moon – and later, Mars.

*Note: Origami is a popular Japanese art of paper folding, with the goal to transform a flat square sheet of paper into a finished sculpture through various folding and sculpting techniques, such as the ever-popular paper crane. Although most often associated with Japanese culture, there have also been similar paper folding traditions in Europe and China.

Bottom line: Origami, the elegant Japanese art of paper folding, is now being used in futuristic designs for human habitats on the moon and Mars. It’s an excellent example of blending old techniques with new ideas, and shows the kinds of creative thinking needed if humans are ever to inhabit other worlds.

Source: Self Deployable Origami for MoonMars Architecture

Via Europlanet

from EarthSky https://ift.tt/2ItQykr

Songbird data yields new theory for learning sensorimotor skills

"Our findings suggest that an animal knows that even the perfect neural command is not going to result in the right outcome every time," says Emory biophysicist Ilya Nemenman. (Image courtesy Samuel Sober.)

By Carol Clark

Songbirds learn to sing in a way similar to how humans learn to speak — by listening to their fathers and trying to duplicate the sounds. The bird’s brain sends commands to the vocal muscles to sing what it hears, and then the brain keeps trying to adjust the command until the sound echoes the one made by the parent.

During such trial-and-error processes of sensorimotor learning, a bird remembers not just the best possible command, but a whole suite of possibilities, suggests a study by scientists at Emory University.

The Proceedings of the National Academy of the Sciences (PNAS) published the study results, which include a new mathematical model for the distribution of sensory errors in learning.

“Our findings suggest that an animal knows that even the perfect neural command is not going to result in the right outcome every time,” says Ilya Nemenman, an Emory professor of biophysics and senior author of the paper. “Animals, including humans, want to explore and keep track of a range of possibilities when learning something in order to compensate for variabilities.”

Nemenman uses the example of learning to swing a tennis racket. “You’re only rarely going to hit the ball in the racket’s exact sweet spot,” he says. “And every day when you pick up the racket to play your swing is going to be a little bit different, because your body is different, the racket and the ball are different, and the environmental conditions are different. So your body needs to remember a whole range of commands, in order to adapt to these different situations and get the ball to go where you want.”

First author of the study is Baohua Zhou, a graduate student of physics. Co-authors include David Hofmann and Itai Pinkoviezky (post-doctoral fellows in physics) and Samuel Sober, an associate professor of biology.

Traditional theories of learning propose that animals use sensory error signals to zero in on the optimal motor command, based on a normal distribution of possible errors around it — what is known as a bell curve. Those theories, however, cannot explain the behavioral observations that small sensory errors are more readily corrected, while the larger ones may be ignored by the animal altogether.

For the PNAS paper, the researchers analyzed experimental data on Bengalese finches collected in previous work with the Sober lab. The lab uses finches as a model system for understanding how the brain controls complex vocal behavior and motor behavior in general.

Miniature headphones were custom-fitted to adult birds and used to provide auditory feedback in which the pitch that the bird perceives it vocalizes at could be manipulated, replacing what the bird hears — its natural auditory feedback — with the manipulated version. The birds would try to correct the pitch they were hearing to match the sound they were trying to make. Experiments allowed the researchers to record and measure the relationship between the size of a vocal error the bird perceives, and the probability of the brain making a correction of a specific size.

The researchers analyzed the data and found that the variability of errors in correction did not have the normal distribution of a bell curve, as previously proposed. Instead, the distribution had long tails of variability, indicating that the animal believed that even large fluctuations in the motor commands could sometimes produce a correct pitch. The researchers also found that the birds combined their hypotheses about the relationship between the motor command and the pitch with the new information that their brains received from their ears while singing. In fact, they did this surprisingly accurately.

“The birds are not just trying to sing in the best possible way, but appear to be exploring and trying wide variations,” Nemenman says. “In this way, they learn to correct small errors, but they don’t even try to correct large errors, unless the large error is broken down and built up gradually.”

The researchers created a mathematical model for this process, revealing the pattern of how small errors are corrected quickly and large errors take much longer to correct, and might be neglected altogether, when they contradict the animal’s “beliefs” about the errors that its sensorimotor system can produce.

“Our model provides a new theory for how an animal learns, one that allows us to make predictions for learning that we have tested experimentally,” Nemenman says.

The researchers are now exploring if this model can be used to predict learning in other animals, as well as predicting better rehabilitative protocols for people dealing with major disruptions to their learned behaviors, such as when recovering from a stroke.

The work was funded by the National Institutes of Health BRAIN Initiative, the James S. McDonnell Foundation, and the National Science Foundation. The NVIDIA corporation donated high-performance computing hardware that supported the work.

Related:
BRAIN grant to fund study of how the mind learns
How songbirds learn to sing

from eScienceCommons http://esciencecommons.blogspot.com/2018/10/songbird-data-yields-new-theory-for.html

"Our findings suggest that an animal knows that even the perfect neural command is not going to result in the right outcome every time," says Emory biophysicist Ilya Nemenman. (Image courtesy Samuel Sober.)

By Carol Clark

Songbirds learn to sing in a way similar to how humans learn to speak — by listening to their fathers and trying to duplicate the sounds. The bird’s brain sends commands to the vocal muscles to sing what it hears, and then the brain keeps trying to adjust the command until the sound echoes the one made by the parent.

During such trial-and-error processes of sensorimotor learning, a bird remembers not just the best possible command, but a whole suite of possibilities, suggests a study by scientists at Emory University.

The Proceedings of the National Academy of the Sciences (PNAS) published the study results, which include a new mathematical model for the distribution of sensory errors in learning.

“Our findings suggest that an animal knows that even the perfect neural command is not going to result in the right outcome every time,” says Ilya Nemenman, an Emory professor of biophysics and senior author of the paper. “Animals, including humans, want to explore and keep track of a range of possibilities when learning something in order to compensate for variabilities.”

Nemenman uses the example of learning to swing a tennis racket. “You’re only rarely going to hit the ball in the racket’s exact sweet spot,” he says. “And every day when you pick up the racket to play your swing is going to be a little bit different, because your body is different, the racket and the ball are different, and the environmental conditions are different. So your body needs to remember a whole range of commands, in order to adapt to these different situations and get the ball to go where you want.”

First author of the study is Baohua Zhou, a graduate student of physics. Co-authors include David Hofmann and Itai Pinkoviezky (post-doctoral fellows in physics) and Samuel Sober, an associate professor of biology.

Traditional theories of learning propose that animals use sensory error signals to zero in on the optimal motor command, based on a normal distribution of possible errors around it — what is known as a bell curve. Those theories, however, cannot explain the behavioral observations that small sensory errors are more readily corrected, while the larger ones may be ignored by the animal altogether.

For the PNAS paper, the researchers analyzed experimental data on Bengalese finches collected in previous work with the Sober lab. The lab uses finches as a model system for understanding how the brain controls complex vocal behavior and motor behavior in general.

Miniature headphones were custom-fitted to adult birds and used to provide auditory feedback in which the pitch that the bird perceives it vocalizes at could be manipulated, replacing what the bird hears — its natural auditory feedback — with the manipulated version. The birds would try to correct the pitch they were hearing to match the sound they were trying to make. Experiments allowed the researchers to record and measure the relationship between the size of a vocal error the bird perceives, and the probability of the brain making a correction of a specific size.

The researchers analyzed the data and found that the variability of errors in correction did not have the normal distribution of a bell curve, as previously proposed. Instead, the distribution had long tails of variability, indicating that the animal believed that even large fluctuations in the motor commands could sometimes produce a correct pitch. The researchers also found that the birds combined their hypotheses about the relationship between the motor command and the pitch with the new information that their brains received from their ears while singing. In fact, they did this surprisingly accurately.

“The birds are not just trying to sing in the best possible way, but appear to be exploring and trying wide variations,” Nemenman says. “In this way, they learn to correct small errors, but they don’t even try to correct large errors, unless the large error is broken down and built up gradually.”

The researchers created a mathematical model for this process, revealing the pattern of how small errors are corrected quickly and large errors take much longer to correct, and might be neglected altogether, when they contradict the animal’s “beliefs” about the errors that its sensorimotor system can produce.

“Our model provides a new theory for how an animal learns, one that allows us to make predictions for learning that we have tested experimentally,” Nemenman says.

The researchers are now exploring if this model can be used to predict learning in other animals, as well as predicting better rehabilitative protocols for people dealing with major disruptions to their learned behaviors, such as when recovering from a stroke.

The work was funded by the National Institutes of Health BRAIN Initiative, the James S. McDonnell Foundation, and the National Science Foundation. The NVIDIA corporation donated high-performance computing hardware that supported the work.

Related:
BRAIN grant to fund study of how the mind learns
How songbirds learn to sing

from eScienceCommons http://esciencecommons.blogspot.com/2018/10/songbird-data-yields-new-theory-for.html

Smoke over Yosemite in September

View larger. | Photo taken at sunset, inside Yosemite National Park, by Abhit Patil.

Last summer’s deadly Ferguson Fire near Yosemite National Park raged for more than a month. By late August, 2018, it was 100% contained, but the smoke still hung over Yosemite’s valleys in early September, when Abhijit Patil captured this image on September 7. He wrote:

The smoke from the wild fires still lingers inside the Yosemite Valley with occasional fires starting in the middle of the night. The smoky valley gets lit up with sun rays during sunset creating a nice contrast of shadows and lights.

Nikon D750, Nikkor 24-120mm f/4 lens, Vanguard Alto pro tripod.

HDR image merged in Lightroom and processed in Photoshop.

According to the National Park Service’s Yosemite Fire Information and Updates page, as of September 27:

There are multiple fires burning in Yosemite National Park’s wilderness. Wildfires when caused by lightning are a natural phenomenon on the landscape. Fire managers work to restore healthy forests and reduce the threat of extensive, severe fire by allowing some lightning-ignited wildfires to burn.

Bottom line: Photo of smoke from the Ferguson Fire, hanging over Yosemite Valley in early September, 2018.

from EarthSky https://ift.tt/2xYaJD9

View larger. | Photo taken at sunset, inside Yosemite National Park, by Abhit Patil.

Last summer’s deadly Ferguson Fire near Yosemite National Park raged for more than a month. By late August, 2018, it was 100% contained, but the smoke still hung over Yosemite’s valleys in early September, when Abhijit Patil captured this image on September 7. He wrote:

The smoke from the wild fires still lingers inside the Yosemite Valley with occasional fires starting in the middle of the night. The smoky valley gets lit up with sun rays during sunset creating a nice contrast of shadows and lights.

Nikon D750, Nikkor 24-120mm f/4 lens, Vanguard Alto pro tripod.

HDR image merged in Lightroom and processed in Photoshop.

According to the National Park Service’s Yosemite Fire Information and Updates page, as of September 27:

There are multiple fires burning in Yosemite National Park’s wilderness. Wildfires when caused by lightning are a natural phenomenon on the landscape. Fire managers work to restore healthy forests and reduce the threat of extensive, severe fire by allowing some lightning-ignited wildfires to burn.

Bottom line: Photo of smoke from the Ferguson Fire, hanging over Yosemite Valley in early September, 2018.

from EarthSky https://ift.tt/2xYaJD9

Moon lights up Gemini in early October

On the mornings of October 2 and 3, 2018, rise before daybreak to see the moon shining in front of the constellation Gemini the Twins. You’ll have no trouble seeing Gemini’s two brightest stars, Castor and Pollux, near the moon.

These stars are sometimes called “twins,” but they don’t look alike in the sky. Pollux is brighter and more golden. Castor shines pure white.

Then – as the week passes – watch the moon move. It’ll be in front of Cancer the Crab – the faintest constellation of the zodiac – to the east of Gemini on October 4. Cancer is so faint that it’ll be all but impossible to see on that morning. But let the moon orient you so that you can come back later to view Cancer’s hidden treasure. More about it below.

Although the sky chart above is designed for temperate latitudes in North America, you’ll see the moon passing through Gemini and Cancer from all parts of the world. The moon moves in front of the constellations of the zodiac at the rate of about 1/2 degree (the moon’s own angular diameter) eastward per hour. So – for example – if you’re in the world’s Eastern Hemisphere at dawn on October 2 and 3, you’ll see the moon offset a bit, with respect to our chart, toward the previous date.

No matter where you are, just look for the moon. The stars near it on the mornings of October 2 and 3 will be Gemini’s stars. These two stars will be noticeable – even when the moon moves away – for being bright and close together on the sky’s dome.

Sky chart of the constellation Gemini via the International Astronomical Union (IAU). When the moon is no longer in front of Gemini, draw an imaginary line from the easternmost star of Orion’s Belt and through the bright ruddy star Betelgeuse to locate the Gemini stars, Castor and Pollux.

The lit side of the waning moon moon always points eastward – the moon’s direction of travel – relative to the backdrop stars of the zodiac. So, as the moon makes its monthly rounds, it’ll sweep to the south of the Gemini stars, Castor and Pollux, and to the north of Procyon, the Little Dog Star, as it heads for the faint constellation Cancer.

Click here to know the moon’s present position in front the constellations of the zodiac.

The constellation Cancer via the IAU. On a dark night, look for the Beehive star cluster (M44) to make a triangle with the Gemini stars, Castor and Pollux, and the bright star Procyon.

Cancer’s hidden treasure. Cancer makes up for its lackluster stars with a beautiful deep-sky object within its boundaries. The Beehive cluster (aka Messier 44) is one of the most magnificent star clusters in all the heavens. On a dark night – with no moon – this cluster appears as a tiny faint cloud to the unaided eye. Through binoculars, this bit of haze explodes into a sparkling array of stars.

The lit side of the moon will be pointing in the direction of the Beehive cluster on October 2 and 3, and then will pass 1.2 degrees south of the Beehive on October 4. Try to note the stars around the moon on these mornings. Then come back when the moon has moved away to view the Beehive.

Beehive star cluster, aka M44, by Fred Espenak at AstroPixels. Used with permission.

By the way, the moon reaches its half-illuminated last quarter phase on October 2. It’s the first of two October 2018 last quarter moons. Read more about the October 2 last quarter moon.

Bottom line: Wake up before dawn in early October 2018, and let the waning moon show you the zodiacal constellations Gemini and Cancer.

from EarthSky https://ift.tt/2NeRycG

On the mornings of October 2 and 3, 2018, rise before daybreak to see the moon shining in front of the constellation Gemini the Twins. You’ll have no trouble seeing Gemini’s two brightest stars, Castor and Pollux, near the moon.

These stars are sometimes called “twins,” but they don’t look alike in the sky. Pollux is brighter and more golden. Castor shines pure white.

Then – as the week passes – watch the moon move. It’ll be in front of Cancer the Crab – the faintest constellation of the zodiac – to the east of Gemini on October 4. Cancer is so faint that it’ll be all but impossible to see on that morning. But let the moon orient you so that you can come back later to view Cancer’s hidden treasure. More about it below.

Although the sky chart above is designed for temperate latitudes in North America, you’ll see the moon passing through Gemini and Cancer from all parts of the world. The moon moves in front of the constellations of the zodiac at the rate of about 1/2 degree (the moon’s own angular diameter) eastward per hour. So – for example – if you’re in the world’s Eastern Hemisphere at dawn on October 2 and 3, you’ll see the moon offset a bit, with respect to our chart, toward the previous date.

No matter where you are, just look for the moon. The stars near it on the mornings of October 2 and 3 will be Gemini’s stars. These two stars will be noticeable – even when the moon moves away – for being bright and close together on the sky’s dome.

Sky chart of the constellation Gemini via the International Astronomical Union (IAU). When the moon is no longer in front of Gemini, draw an imaginary line from the easternmost star of Orion’s Belt and through the bright ruddy star Betelgeuse to locate the Gemini stars, Castor and Pollux.

The lit side of the waning moon moon always points eastward – the moon’s direction of travel – relative to the backdrop stars of the zodiac. So, as the moon makes its monthly rounds, it’ll sweep to the south of the Gemini stars, Castor and Pollux, and to the north of Procyon, the Little Dog Star, as it heads for the faint constellation Cancer.

Click here to know the moon’s present position in front the constellations of the zodiac.

The constellation Cancer via the IAU. On a dark night, look for the Beehive star cluster (M44) to make a triangle with the Gemini stars, Castor and Pollux, and the bright star Procyon.

Cancer’s hidden treasure. Cancer makes up for its lackluster stars with a beautiful deep-sky object within its boundaries. The Beehive cluster (aka Messier 44) is one of the most magnificent star clusters in all the heavens. On a dark night – with no moon – this cluster appears as a tiny faint cloud to the unaided eye. Through binoculars, this bit of haze explodes into a sparkling array of stars.

The lit side of the moon will be pointing in the direction of the Beehive cluster on October 2 and 3, and then will pass 1.2 degrees south of the Beehive on October 4. Try to note the stars around the moon on these mornings. Then come back when the moon has moved away to view the Beehive.

Beehive star cluster, aka M44, by Fred Espenak at AstroPixels. Used with permission.

By the way, the moon reaches its half-illuminated last quarter phase on October 2. It’s the first of two October 2018 last quarter moons. Read more about the October 2 last quarter moon.

Bottom line: Wake up before dawn in early October 2018, and let the waning moon show you the zodiacal constellations Gemini and Cancer.

from EarthSky https://ift.tt/2NeRycG

Army Looks to Nature to Improve Body Armor

Future soldiers will be better protected in combat by stronger and lighter body armor thanks to innovative work at the U.S. Army Research Laboratory.

from https://ift.tt/2xMjPTa

Future soldiers will be better protected in combat by stronger and lighter body armor thanks to innovative work at the U.S. Army Research Laboratory.

from https://ift.tt/2xMjPTa