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🟢What happens when you have a concussion?

#Health #Memory #Personality #Psychology #Public_Health

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🟢What happens when you have a concussion?

Each year in the United States, players of sports and recreational activities receive between 2.5 and 4 million concussions. How dangerous are all those concussions? The answer is complicated, and lies in how the brain responds when something strikes it. The brain is made of soft fatty tissue, with a consistency something like jello. Inside its protective membranes and the skull's hard casing, this delicate organ is usually well-shielded. But a sudden jolt can make the brain shift and bump against the skull's hard interior, and unlike jello, the brain's tissue isn't uniform. It's made of a vast network of 90 billion neurons, which relay signals through their long axons to communicate throughout the brain and control our bodies. This spindly structure makes them very fragile so that when impacted, neurons will stretch and even tear. That not only disrupts their ability to communicate but as destroyed axons begin to degenerate, they also release toxins causing the death of other neurons, too. This combination of events causes a concussion. The damage can manifest in many different ways including blackout, headache, blurry vision, balance problems, altered mood and behavior, problems with memory, thinking, and sleeping, and the onset of anxiety and depression. Every brain is different, which explains why people's experiences of concussions vary so widely. Luckily, the majority of concussions fully heal and symptoms disappear within a matter of days or weeks. Lots of rest and a gradual return to activity allows the brain to heal itself. On the subject of rest, many people have heard that you're not supposed to sleep shortly after receiving a concussion because you might slip into a coma. That's a myth. So long as doctors aren't concerned there may also be a more severe brain injury, like a brain bleed, there's no documented problem with going to sleep after a concussion. Sometimes, victims of concussion can experience something called post-concussion syndrome, or PCS. People with PCS may experience constant headaches, learning difficulties, and behavioral symptoms that even affect their personal relationships for months or years after the injury. Trying to play through a concussion, even for only a few minutes, or returning to sports too soon after a concussion, makes it more likely to develop PCS. In some cases, a concussion can be hard to diagnose because the symptoms unfold slowly over time. That's often true of subconcussive impacts which result from lower impact jolts to the head than those that cause concussions. This category of injury doesn't cause noticable symptoms right away, but can lead to severe degenerative brain diseases over time if it happens repeatedly. Take soccer players, who are known for repeatedly heading soccer balls. Using a technique called Diffusion Tensor Imaging, we're beginning to find out what effect that has on the brain. This method allows scientists to find large axon bundles and see how milder blows might alter them structurally. In 2013, researchers using this technique discovered that athletes who had headed the ball most, about 1,800 times a year, had damaged the structural integrity of their axon bundles. The damage was similar to how a rope will fail when the individual fibers start to fray. Those players also performed worse on short-term memory tests, so even though no one suffered full-blown concussions, these subconcussive hits added up to measurable damage over time. In fact, researchers know that an overload of subconcussive hits is linked to a degenerative brain disease known as Chronic Traumatic Encephalopathy, or CTE. People with CTE suffer from changes in their mood and behavior that begin appearing in their 30s or 40s followed by problems with thinking and memory that can, in some cases, even result in dementia. The culprit is a protein called tau. Usually, tau proteins support tiny tubes inside our axons called microtubules.

It's thought that repeated subconcussive hits damage the microtubules, causing the tau proteins to dislodge and clump together. The clumps disrupt transport and communication along the neuron and drive the breakdown of connections within the brain. Once the tau proteins start clumping together, they cause more clumps to form and continue to spread throughout the brain, even after head impacts have stopped. The data show that at least among football players, between 50 and 80% of concussions go unreported and untreated. Sometimes that's because it's hard to tell a concussion has occurred in the first place. But it's also often due to pressure or a desire to keep going despite the fact that something's wrong. This doesn't just undermine recovery. It's also dangerous. Our brains aren't invincible. They still need us to shield them from harm and help them undo damage once it's been done.

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🟢What it takes to launch a telescope?

#Science #Astronomy #Telescopes #Technology #Space #Physics #Universe #Collaboration #Personal_Growth

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🟢What it takes to launch a telescope?

I'm an astronomer who builds telescopes. I build telescopes because, number one, they are awesome. But number two, I believe if you want to discover a new thing about the universe, you have to look at the universe in a new way. New technologies in astronomy -- things like lenses, photographic plates, all the way up to space telescopes -- each gave us new ways to see the universe and directly led to a new understanding of our place in it.
But those discoveries come with a cost. It took thousands of people and 44 years to get the Hubble Space Telescope from an idea into orbit. It takes time, it takes a tolerance for failure, it takes individual people choosing every day not to give up. I know how hard that choice is because I live it. The reality of my job is that I fail almost all the time and still keep going, because that's how telescopes get built.
The telescope I helped build is called the faint intergalactic-medium red-shifted emission balloon, which is a mouthful, so we call it "FIREBall." And don't worry, it is not going to explode at the end of this story. I've been working on FIREBall for more than 10 years and now lead the team of incredible people who built it. FIREBall is designed to observe some of the faintest structures known: huge clouds of hydrogen gas. These clouds are giant. They are even bigger than whatever you're thinking of. They are huge, huge clouds of hydrogen that we think flow into and out of galaxies. I work on FIREBall because what I really want is to take our view of the universe from one with just light from stars to one where we can see and measure every atom that exists. That's all that I want to do.
But observing at least some of those atoms is crucial to our understanding of why galaxies look the way they do. I want to know how that hydrogen gas gets into a galaxy and creates a star. My work on FIREBall started in 2008, working not on the telescope but on the light sensor, which is the heart of any telescope. This new sensor was being developed by a team that I joined at NASA's Jet Propulsion Laboratory. And our goal was to prove that this sensor would work really well to detect that hydrogen gas.
In my work on this, I destroyed several very, very, very expensive sensors before realizing that the machine I was using created a plasma that shorted out anything electrical that we put in it. We used a different machine, there were other challenges, and it took years to get it right. But when that first sensor worked, it was glorious. And our sensors are now 10 times better than the previous state of the art and are getting put into all kinds of new telescopes. Our sensors will give us a new way to see the universe and our place in it.
So, sensors done, time to build a telescope. And FIREBall is weird as far as telescopes go, because it's not in space, and it's not on the ground. Instead, it hangs on a cable from a giant balloon and observes for one night only from 130,000 feet in the stratosphere, at the very edge of space. This is partly because the edge of space is much cheaper than actual space.
So building it, of course, more failures: mirrors that failed, scratched mirrors that had to be remade; cooling system failures, an entire system that had to be remade; calibration failures, we ran tests again and again and again and again; failures when you literally least expect them: we had an adorable but super angry baby falcon that landed on our spectrograph tank one day.
Although to be fair, this was the greatest day in the history of this project.
I really loved that falcon.
But falcon damage fixed, we got it built for an August 2017 launch attempt -- and then failed to launch, due to six weeks of continuous rain in the New Mexico desert.
Our spirits dampened, we showed up again, August 2018, year 10. And on the morning of September 22nd, we finally got the telescope launched.

I have put so much of myself -- my whole life -- into this project, and I, like, still can't believe that that happened. And I have this picture that's taken right around sunset on that day of our balloon, FIREBall hanging from it, and the nearly full moon. And I love this picture. God, I love it.
But I look at it, and it makes me want to cry, because when fully inflated, these balloons are spherical, and this one isn't. It's shaped like a teardrop. And that's because there is a hole in it. Sometimes balloons fail, too. FIREBall crash-landed in the New Mexico desert, and we didn't get the data that we wanted. And at the end of that day, I thought to myself, "Why am I doing this?"
And I've thought a lot about why since that day. And I've realized that all of my work has been full of things that break and fail, that we don't understand and they fail, that we just get wrong the first time, and so they fail. I think about the thousands of people who built Hubble and how many failures they endured. There were countless failures, heartbreaking failures, even when it was in space. And none of those failures were a reason for them to give up. I think about why I love my job. I want to know what is happening in the universe. You all want to know what's happening in the universe, too. I want to know what's going on with that hydrogen. And so I've realized that discovery is mostly a process of finding things that don't work, and failure is inevitable when you're pushing the limits of knowledge. And that's what I want to do.
So I'm choosing to keep going. And our team is going to do what everyone who has ever built anything before us has done: we're going to try again, in 2020.
And it might feel like a failure today -- and it really does -- but it's only going to stay a failure if I give up.
Thank you very much.

#Science #Astronomy #Telescopes #Technology #Space #Physics #Universe #Collaboration #Personal_Growth

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🏕🔥سونا فنلاندی میدونی چطوریه؟
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🟢Adventures of an asteroid hunter

#Astronomy #Asteroid #Discovery #Exploration #Collaboration #Global_Issues #Nature #Physics #Science #Technology #Solar_System #TED_Fellows #Universe #Space #TED_Books

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🟢Adventures of an asteroid hunter

I am holding something remarkably old. It is older than any human artifact, older than life on Earth, older than the continents and the oceans between them. This was formed over four billion years ago in the earliest days of the solar system while the planets were still forming. This rusty lump of nickel and iron may not appear special, but when it is cut open ... you can see that it is different from earthly metals. This pattern reveals metallic crystals that can only form out in space where molten metal can cool extremely slowly, a few degrees every million years. This was once part of a much larger object, one of millions left over after the planets formed. We call these objects asteroids.
Asteroids are our oldest and most numerous cosmic neighbors. This graphic shows near-Earth asteroids orbiting around the Sun, shown in yellow, and swinging close to the Earth's orbit, shown in blue. The sizes of the Earth, Sun and asteroids have been greatly exaggerated so you can see them clearly. Teams of scientists across the globe are searching for these objects, discovering new ones every day, steadily mapping near-Earth space. Much of this work is funded by NASA. I think of the search for these asteroids as a giant public works project, but instead of building a highway, we're charting outer space, building an archive that will last for generations.
These are the 1,556 near-Earth asteroids discovered just last year. And these are all of the known near-Earth asteroids, which at last count was 13,733. Each one has been imaged, cataloged and had its path around the Sun determined. Although it varies from asteroid to asteroid, the paths of most asteroids can be predicted for dozens of years. And the paths of some asteroids can be predicted with incredible precision. For example, scientists at the Jet Propulsion Laboratory predicted where the asteroid Toutatis was going to be four years in advance to within 30 kilometers. In those four years, Toutatis traveled 8.5 billion kilometers. That's a fractional precision of 0.000000004.
Now, the reason I have this beautiful asteroid fragment is because, like all neighbors, asteroids sometimes drop by unexpectedly.
Three years ago today, a small asteroid exploded over the city of Chelyabinsk, Russia. That object was about 19 meters across, or about as big as a convenience store. Objects of this size hit the Earth every 50 years or so.
66 million years ago, a much larger object hit the Earth, causing a massive extinction. 75 percent of plant and animal species were lost, including, sadly, the dinosaurs. That object was about 10 kilometers across, and 10 kilometers is roughly the cruising altitude of a 747 jet. So the next time you're in an airplane, snag a window seat, look out and imagine a rock so enormous that resting on the ground, it just grazes your wingtip. It's so wide that it takes your plane one full minute to fly past it. That's the size of the asteroid that hit the Earth.
It has only been within my lifetime that asteroids have been considered a credible threat to our planet. And since then, there's been a focused effort underway to discover and catalog these objects. I am lucky enough to be part of this effort. I'm part of a team of scientists that use NASA's NEOWISE telescope. Now, NEOWISE was not designed to find asteroids. It was designed to orbit the earth and look far beyond our solar system to seek out the coldest stars and the most luminous galaxies. And it did that very well for its designed lifetime of seven months. But today, six years later, it's still going. We've repurposed it to discover and study asteroids. And although it's a wonderful little space robot, these days it's kind of like a used car. The cryogen that used to refrigerate its sensors is long gone, so we joke that its air-conditioning is broken. It's got 920 million miles on the odometer, but it still runs great and reliably takes a photograph of the sky every 11 seconds. It's taken 23 photos since I began speaking to you.

One of the reasons NEOWISE is so valuable is that it sees the sky in the thermal infrared. That means that instead of seeing the sunlight that asteroids reflect, NEOWISE sees the heat that they emit. This is a vital capability since some asteroids are as dark as coal and can be difficult or impossible to spot with other telescopes. But all asteroids, light or dark, shine brightly for NEOWISE.
Astronomers are using every technique at their disposal to discover and study asteroids. In 2010, a historic milestone was reached. The community, together, discovered over 90 percent of asteroids bigger than one kilometer across -- objects capable of massive destruction to Earth. But the job's not done yet. An object 140 meters or bigger could decimate a medium-sized country. So far, we've only found 25 percent of those.
We must keep searching the sky for near-Earth asteroids. We are the only species able to understand calculus or build telescopes. We know how to find these objects. This is our responsibility. If we found a hazardous asteroid with significant early warning, we could nudge it out of the way. Unlike earthquakes, hurricanes or volcanic eruptions, an asteroid impact can be precisely predicted and prevented. What we need to do now is map near-Earth space. We must keep searching the sky.
Thank you.

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🟢Autofocusing reading glasses of the future

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🟢Autofocusing reading glasses of the future

Every single one of us will lose or has already lost something we rely on every single day. I am of course talking about our keys.
Just kidding. What I actually want to talk about is one of our most important senses: vision. Every single day we each lose a little bit of our ability to refocus our eyes until we can't refocus at all. We call this condition presbyopia, and it affects two billion people worldwide. That's right, I said billion. If you haven't heard of presbyopia, and you're wondering, "Where are these two billion people?" here's a hint before I get into the details. It's the reason why people wear reading glasses or bifocal lenses.
I'll get started by describing the loss in refocusing ability leading up to presbyopia. As a newborn, you would have been able to focus as close as six and a half centimeters, if you wished to. By your mid-20s, you have about half of that focusing power left. 10 centimeters or so, but close enough that you never notice the difference. By your late 40s though, the closest you can focus is about 25 centimeters, maybe even farther. Losses in focusing ability beyond this point start affecting near-vision tasks like reading, and by the time you reach age 60, nothing within a meter radius of you is clear.
Right now some of you are probably thinking, that sounds bad but he means you in a figurative sense, only for the people that actually end up with presbyopia. But no, when I say you, I literally mean that every single one of you will someday be presbyopic if you aren't already. That sounds a bit troubling. I want to remind you that presbyopia has been with us for all of human history and we've done a lot of different things to try and fix it. So to start, let's imagine that you're sitting at a desk, reading. If you were presbyopic, it might look a little something like this. Anything close by, like the magazine, will be blurry. Moving on to solutions. First, reading glasses. These have lenses with a single focal power tuned so that near objects come into focus. But far objects necessarily go out of focus, meaning you have to constantly switch back and forth between wearing and not wearing them. To solve this problem Benjamin Franklin invented what he called "double spectacles." Today we call those bifocals, and what they let him do was see far when he looked up and see near when he looked down. Today we also have progressive lenses which get rid of the line by smoothly varying the focal power from top to bottom. The downside to both of these is that you lose field of vision at any given distance, because it gets split up from top to bottom like this. To see why that's a problem, imagine that you're climbing down a ladder or stairs. You look down to get your footing but it's blurry. Why would it be blurry? Well, you look down and that's the near part of the lens, but the next step was past arm's reach, which for your eyes counts as far.
The next solution I want to point out is a little less common but comes up in contact lenses or LASIK surgeries, and it's called monovision. It works by setting up the dominant eye to focus far and the other eye to focus near. Your brain does the work of intelligently putting together the sharpest parts from each eye's view, but the two eyes see slightly different things, and that makes it harder to judge distances binocularly.
So where does that leave us? We've come up with a lot of solutions but none of them quite restore natural refocusing. None of them let you just look at something and expect it to be in focus.
But why? Well, to explain that we'll want to take a look at the anatomy of the human eye. The part of the eye that allows us to refocus to different distances is called the crystalline lens. There are muscles surrounding the lens that can deform it into different shapes, which in turn changes its focusing power. What happens when someone becomes presbyopic? It turns out that the crystalline lens stiffens to the point that it doesn't really change shape anymore.

Now, thinking back on all the solutions I listed earlier, we can see that they all have something in common with the others but not with our eyes, and that is that they're all static. It's like the optical equivalent of a pirate with a peg leg. What is the optical equivalent of a modern prosthetic leg?
The last several decades have seen the creation and rapid development of what are called "focus-tunable lenses." There are several different types. Mechanically-shifted Alvarez lenses, deformable liquid lenses and electronically-switched, liquid crystal lenses. Now these have their own trade-offs, but what they don't skimp on is the visual experience. Full-field-of-view vision that can be sharp at any desired distance.
OK, great. The lenses we need already exist. Problem solved, right? Not so fast. Focus-tunable lenses add a bit of complexity to the equation. The lenses don't have any way of knowing what distance they should be focused to. What we need are glasses that, when you're looking far, far objects are sharp, and when you look near, near objects come into focus in your field of view, without you having to think about it.
What I've worked on these last few years at Stanford is building that exact intelligence around the lenses. Our prototype borrows technology from virtual and augmented reality systems to estimate focusing distance. We have an eye tracker that can tell what direction our eyes are focused in. Using two of these, we can triangulate your gaze direction to get a focus estimate. Just in case though, to increase reliability, we also added a distance sensor. The sensor is a camera that looks out at the world and reports distances to objects. We can again use your gaze direction to get a distance estimate for a second time. We then fuse those two distance estimates and update the focus-tunable lens power accordingly.
The next step for us was to test our device on actual people. So we recruited about 100 presbyopes and had them test our device while we measured their performance. What we saw convinced us right then that autofocals were the future. Our participants could see more clearly, they could focus more quickly and they thought it was an easier and better focusing experience than their current correction. To put it simply, when it comes to vision, autofocals don't compromise like static corrections in use today do.
But I don't want to get ahead of myself. There's a lot of work for my colleagues and me left to do. For example, our glasses are a bit --
bulky, maybe? And one reason for this is that we used bulkier components that are often intended for research use or industrial use. Another is that we need to strap everything down because current eye-tracking algorithms don't have the robustness that we need. So moving forward, as we move from a research setting into a start-up, we plan to make future autofocals eventually look a little bit more like normal glasses. For this to happen, we'll need to significantly improve the robustness of our eye-tracking solution. We'll also need to incorporate smaller and more efficient electronics and lenses. That said, even with our current prototype, we've shown that today's focus-tunable lens technology is capable of outperforming traditional forms of static correction. So it's only a matter of time.
It's pretty clear that in the near future, instead of worrying about which pair of glasses to use and when, we'll be able to just focus on the important things.
Thank you.

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