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dailykitten_feedPlease join me in putting paws in the air for today’s Star Kit, Dorian. She is an 8 week old Blue Russian from Edinburgh, Scotland.
Hello everyone, I have just adopt Dorian an amazing male Blue Russian kitten. I have him since 2 days now and is still on the “hiding & crying” mood. Hopefully soon will get used to the new environment and me 
science_blog_feed
A University of Central Florida study has found that a gene variant, thought to be carried by nearly 25 percent of the population, increases the odds of developing depression. People with apolipoprotein-E4, called ApoE4 for ... Read morescience_blog_feed
In 1928, physicist Paul Dirac made the stunning prediction that every fundamental particle in the universe has an antiparticle – its identical twin but with opposite charge. When particle and antiparticle met they would be ... Read morescience_blog_feed
HSE researchers examined the structure of online communities of Russian AIDS denialists – people who deny the reality of HIV and AIDS – and the manner in which they spread their ideas. The findings are ... Read morepennyarcade_feedphd_comics_feed| Piled Higher & Deeper by Jorge Cham |
www.phdcomics.com
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title:
"The Mysteries of SPACE" - originally published
7/19/2017
For the latest news in PHD Comics, CLICK HERE! |
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ittybittykitty_feed
badastronomy_feedJust over two years ago, the New Horizons spacecraft provided humanity with its first close-up photos of Pluto in history.
These images changed the way we see the icy world forever. What we learned was staggering. It has vast, smooth regions on its surface indicating they’re geologically young; mountains as tall as the Rockies but made entirely of water ice; strong implications of liquid water under its surface despite the bone-shattering cold temperatures on the surface.
The close encounter lasted only a few hours, because you have a choice: Get to Pluto in less than a lifetime, or spend more time there. Pluto is so far away that even New Horizons, barreling across the solar system at 14 kilometers every second, still took nearly a decade to get there. It was traveling so rapidly that the visit was short.
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But, despite the rapid flyby, there’s an advantage to moving faster than a speeding bullet: There are other targets out there in the inky depths of the outer solar system, and if you plan things right, you might just get to see them, too.
Even before the Pluto encounter, astronomers started trolling that region of space to look for another suitable target. They found one: 2014 MU69, an icy chunk of debris likely at most 20 – 40 kilometers across. It orbits far, far past Neptune, 6.5 billion kilometers from the Sun. It’s part of the Kuiper Belt, a rag-tag collection of material left over from the formation of the solar system, itself. If you don’t count Pluto (and I do), the first Kuiper Belt Object seen was only in 1992, and we now know of thousands.
But they’re so far away and so small that it’s hard to know what they’re like in detail. And that’s why MU69 is so important. New Horizons will show it to us up close for the first time.
The plan is for the spacecraft to fly within 10,000 km of MU69 on January 1, 2019. Maybe closer. But, to do that, we need to know more about it. How big is it? What shape is it? Is there anything else around it that could interfere with the flyby, like moons, rings, or debris?
These things are difficult to determine, but astronomers got a big clue this week due to geometry. In this case, the stars literally aligned.
Well, the Earth, MU69, and a star aligned. On July 17, 2017, from certain points on Earth, MU69 appeared to pass directly in front of a faint star. Astronomers call this kind of event an occultation, and when it happens, the star’s light is blocked, and it seems to momentarily disappear! In a sense, in this case, we’re in the shadow of MU69.
The occultation provides critical information: Because we know how fast MU69 is moving across the sky, the length of time the star blinks out tells us the width of MU69.
But there’s more. If you observe the occultation from different locations, you see different parts of MU69 passing in front of the star. If it’s a perfect sphere, then some locations will see a shorter occultation because the star cuts a chord behind it, not the full diameter. In fact, the shape, itself, can be determined by how long the occultation lasts at different positions on Earth.
Map showing the path of the shadow of 2014 MU69 across the Earth. Credit: SwRI
So, New Horizons scientists dispatched telescopes to South America, where the shadow of MU69 was determined to fall across the Earth. In all, a couple of dozen small (40 cm) ‘scopes were deployed, equipped with cameras to record the event.
And…. They caught it! At least five telescopes saw the star blink out. That, too, is very useful: If a ‘scope didn’t see it, then that provides an upper limit to the size of MU69 as well. The entire occultation lasted less than two seconds, too, so timing and location were everything, here.
Animation of the star blinking out as MU69 passed in front of it. This is actual data from the event; the time between frames is 0.2 seconds. Credit:Â NASA / JHUAPL / SwRI / Emily Lakdawalla
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The data are still being processed, and we should have some numbers soon. I’ll note that there were two predicted occultations of two different stars before July 17, but nothing was seen. That means MU69 is probably smaller than previously thought, which, in turn, means it might be more reflective — if we know the distance and how bright it is, then its size depends on how shiny it is. A darker object would have to be bigger to look brighter, so even this non-detection tells us more about it.
My friend and super-solar-system-science communicator Emily Lakdawalla has more about the efforts to record this event. She also wrote a nice piece on what we knew about MU69 from a couple of years back, too.
I can’t stress enough just how difficult this sort of event is to plan! MU69 was only discovered in 2014 using Hubble images. It has a visual magnitude of 27 — that means the faintest star you can see with your unaided eye is 250 million times brighter! Then, using those images, the team had to calculate an orbit for it, and do so with such precision that they could extrapolate where it would be over the next year or two and see if it would pass in front of any stars. Then, they had to plan the logistics of all that travel, coordinating the mission and making sure the data were recorded. Yet, as difficult as all that was, they were able to do it so well and with such accurate timing that several of the telescopes did in fact see the star blink out.
Mind you, MU69 is far, far too faint to even see with the telescopes used. So, the astronomers had to keep taking data and hope.
And it paid off. Now, armed with more data, they’ll be able to plan the upcoming encounter with a little more confidence. As for what we’ll actually see when New Horizons gets to MU69, well, no one really knows.
If we did, it wouldn’t be exploration now, would it? But in less than 17 months, we’ll find out.
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newhorizons_mu69_artwork.jpg bruce_schneier_feedThe press is reporting a $32M theft of the cryptocurrency Ethereum. Like all such thefts, they're not a result of a cryptographic failure in the currencies, but instead a software vulnerability in the software surrounding the currency -- in this case, digital wallets.
This is the second Ethereum hack this week. The first tricked people in sending their Ethereum to another address.
This is my concern about digital cash. The cryptography can be bulletproof, but the computer security will always be an issue.
haskell_weekly_feedWelcome to another issue of Haskell Weekly! Haskell is a purely functional programming language that focuses on correctness, productivity, and expressiveness. This is a weekly summary of what’s going on in its community.
Announcing: the new unliftio library
For the past few years, Francesco Mazzoli and I have discussed issues around monad transformers — and the need to run their actions in IO — on a fairly regular basis. I wrote the monad-unlift library a while ago to try and address these concerns.
Type safe dimensional analysis in Haskell
Years ago my colleague Gustavo asked how I would represent physical units like
m/sorkg*m/s^2as types so the compiler can check that they match up and cancel correctly. F# supports this natively, but it felt weird to have it baked into the type system.
Morgan Stanley open source: hobbes
Over the last few years, I have been developing hobbes — a programming language, JIT compiler, and database system — as part of my work for Morgan Stanley. It has become a critical piece of infrastructure in our low-latency, high-volume trading applications.
NStack is hiring Haskellers in London (onsite/remote) (ad)
NStack lets data scientists and analysts to do sophisticated data work in the cloud without a team of engineers. Come help us build the platform for composable, data-driven microservices, using a mixture of Haskell and Linux systems tech. Reply via the link or email jobs@nstack.com.
Demystifying Haskell assignment
This post clarifies the distinction between
<-and=in Haskell, which sometimes mystifies newcomers to the language. Most languages use only one symbol to assign values (such as=or:=), so why does Haskell use two?
If you look at the original property-based testing library, QuickCheck, tests are very closely tied to types: The way you typically specify a property is by inferring the data that needs to be generated from the types the test function expects for its arguments. This is a bad idea.
Get started with sending SMS in Haskell
Functional programming languages are gaining in popularity so let’s hop on that Haskell bandwagon. With Haskell, you can write clean, concise, and expressive code.
Our platonic ideal of a Haskell library is something that exports a single, coherent concept in such a way that it never needs to be reimplemented. This is not that: scraping is a dirty, error-prone, highly contingent endeavor.
State machine testing with Hedgehog
This is a really nice way to specify and test effectful systems. It’s much more effective than example-testing with canned action sequences. There’s also a lot of potential for test reuse: anything implementing the same interface can use the same property.
The world’s fastest extensible effects framework
I uploaded a new version of
monad-skeleton-0.1.4, an operational monad library. As a result of performance optimization in the new version, extensible, the extensible effects library based on it, is now much faster than the other well-known libraries.
The free monad allows you to build your own custom monad. This lets you use the do notation for whatever you want. I find that a lot of the tutorials on the Free monad have too much build-up, and it’s hard to figure out what the code should actually be at the end.
This week’s package of the week is language-ninja, a library for dealing with the Ninja build language.
stack new can’t be pointed at an intranet sitetshow functionDo you have a beginner-friendly issue you want some help with? Email info@haskellweekly.news to get it included here!
gpuopen_feedTressFX 4 introduces a number of improvements. This blog post focuses on three of these, all of which are tied to simulation:
We’ve also have a couple of bonuses in the sample code. Although not directly part of TressFX, you may find them useful. They are:
TressFX 3 introduced fur support, which essentially means that each hair root can move with the underlying skinned mesh. This was done by streaming out post-skinned triangles, then using those triangles to compute transforms for root hairs. This method is great in that it’s pretty general – it doesn’t matter how the vertices were skinned, and it could also handle blend shapes for example. The drawback is that it relied on knowing which triangle controlled which hair, which was assigned during export of the hairs from Maya®.  If the mesh changed or reordered, or split differently due to material assignments, the hair indices would need to be remapped as well. There was also a fair amount of runtime cost associated with deriving transforms from the triangles for use on the hair.
In TressFX 4, we switched to a more direct skinning model, as was used in Monster Hunter Online. When exporting the hair, you select the mesh as before, but instead of exporting a list of triangle assignments you are exporting bone indices and weights for each hair root. Additionally, there is a table of bone names so they can be easily remapped to the engine’s bone indexing.
Our biggest feature addition for simulation is the introduction of a dynamic signed distance field collision system. This enables high-fidelity collision with dynamically animated, skinned meshes.
The included demo generates three signed distance fields – one for the body, and one for each hand of our skinned character.  Breaking it up this way allows us to focus resolution where needed. We wanted to show response to individual fingers, for example. Each signed distance field is updated every frame.
SSH is another new feature in TressFX 4. The main purpose of this is to handle fast moving animations. When the character changes its speed or direction, it generates a high acceleration and consequently a big external force. Since TressFX hair simulation uses an iteration-based constraint solver, when a high acceleration gets applied, hair can easily lose its physically-correct shapes and shows unpleasant elongation.
Sudden shock handling mitigates these issues by propagating acceleration from the root of the hair to the tip according to a weighting factor.  The weighting factor varies between zero and one. At one, the fur will move completely rigidly – thus giving an alternative to full simulation for a form of simulation level of detail.  In addition to the weight, there’s a threshold setting to only enable it under fast motion.
The sample code includes a few extra tidbits as well. One is a compute-based skinning system, including a Maya exporter that will export mesh geometry, along with skinning weights.  We used this to skin the mesh that serves as input to the signed-distance field system.
To help visualise the signed distance field, we have also included a compute-based marching cubes visualisation system.
We’ve covered quite a bit of the changes to simulation in TressFX 4, from changes to existing approaches (bone-based skinning), new features (SDF collisions and sudden shock propagation), and some related bits in the sample code (compute-based skinning and marching cubes). There’s still quite a bit more we’ve changed and added that we hope to cover in later posts.
The post TressFX 4 Simulation Changes appeared first on GPUOpen.
science_blog_feed
The discovery that the brain can generate new cells – about 700 new neurons each day – has triggered investigations to uncover how this process is regulated. Researchers at Baylor College of Medicine and Jan ... Read morescience_blog_feed
For more than a decade, people have used social media to express themselves and inform and engage users across the globe. Now, a new study by Florida State University researchers examines the impact rising temperatures ... Read morescience_blog_feed
Dogs’ ability to communicate and interact with humans is one the most astonishing differences between them and their wild cousins, wolves. A new study published today in the journal Science Advances identifies genetic changes that ... Read morescience_blog_feed
Several studies have reported associations between proton-pump inhibitor (PPI) use and dementia. New research published on July 18 in Gastroenterology, the official journal of the American Gastroenterological Association (AGA), puts these claims to rest. The ... Read morescience_blog_feed
A study by researchers from Loma Linda University School of Public Health and the Czech Republic has found that timing and frequency of meals play a role in predicting weight loss or gain. Using information ... Read morescience_blog_feed
What’s good for the heart is also good for the brain. Individuals who had better cardiovascular health in young adulthood had larger brain volume and less abnormal brain tissue (relative to their total head size) ... Read morescience_blog_feed
“War for the Planet of the Apes,” the latest movie in the enduring “Planet of the Apes” franchise, took the top spot at the box office on its opening weekend and is one of the ... Read morecakewrecks_feedAw, look at the sweet cake for Sarah-Maude's second birthday:
[squinting]
Although, those balloons look a little odd, don't they? Let's take a closer look...
[eyes bulging] Great Scott! Hide the children!!
And I KNOW you see what I see, people, so don't even try to accuse me of having my mind in the gutter. It's the Fireman cake all over again.
Eric N., thank goodness this was for a safely oblivious 2-year-old. Still, given how obvious those balloons are, I'm pretty sure I'd steer clear of this bakery in the future. Unless it was for a bachelorette party, of course.
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ffutureshistory_monk dailykitten_feed - Dorianscience_blog_feed - Study finds gene variant increases risk for depressionscience_blog_feed - Evidence found for the Majorana fermion, a particle that’s its own antiparticlescience_blog_feed - Social scientists reveal structure of AIDS denialist online communitiespennyarcade_feed - News Post: Here They Are - Your PAX 10!phd_comics_feed - 07/19/17 PHD comic: 'The Mysteries of SPACE'ittybittykitty_feed - So Much Love for Youbadastronomy_feed - The wink of a star reveals a distant target for New Horizonsbruce_schneier_feed - Ethereum Hackshaskell_weekly_feed - Issue 64gpuopen_feed - TressFX 4 Simulation Changesscience_blog_feed - Lunatic Fringe gene plays key role in renewable brainscience_blog_feed - Heat tweet: Users flock to Twitter when temperatures risescience_blog_feed - Dogs, humans share genetic basis for hypersocial behaviorscience_blog_feed - Setting the record straight: PPIs do not cause Dementiascience_blog_feed - Timing and frequency of meals plays role in weight loss or gain.science_blog_feed - How to have a big, healthy brainscience_blog_feed - Four Questions: Could Apes Talk as They Do in the Movies?cakewrecks_feed - Dirty-Minded Decoratorsffutures - The Great Repeal Bill...