Willie Wong
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6accdæ13eff7i319n4o4qrr4s9t12vx... at least, it pays the bills.
6accdæ13eff7i319n4o4qrr4s9t12vx... at least, it pays the bills.
1,576 followers
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Internal e-mail (slightly redacted, emphasis mine):
"It has been brought to my attention there has been a bat in XXX during the evening. If you see a bat, do not try to capture or kill it, contact ORCBS at xxx-xxxx during normal business hours. If it is after 5:00 pm on a weekday or anytime on a weekend please call the bat pager (this is what the folks at ORCBS call it) at xxx.xxx.xxxx and follow the instructions."
"It has been brought to my attention there has been a bat in XXX during the evening. If you see a bat, do not try to capture or kill it, contact ORCBS at xxx-xxxx during normal business hours. If it is after 5:00 pm on a weekday or anytime on a weekend please call the bat pager (this is what the folks at ORCBS call it) at xxx.xxx.xxxx and follow the instructions."
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Last night during the intervals between Olympics events, the trailer for Hidden Figures was released. When people praised the new Ghostbusters for its positive portrayal of women and other underrepresented groups in science, I had some lingering reservations due to it being, after all, comedic fiction. This new movie, however, is based on the real-life story of Katherine Johnson, Dorothy Vaughan, and Mary Jackson, who worked as "computers" for NASA before the transition to electronic computing devices. From Wikipedia:
[Katherine Johnson] calculated the trajectory for the space flight of Alan Shepard, the first American in space, in 1959. She also calculated the launch window for his 1961 Mercury mission. ... In 1962, when NASA used electronic computers for the first time to calculate John Glenn's orbit around Earth, officials called on her to verify the computer's numbers.
The movie is in fact based on the book of the same name by Margot Lee Shetterly, which is available for pre-order now. (It should be published early September.) Shetterly won a Sloan Fellowship in 2014 for work on the book.
[Katherine Johnson] calculated the trajectory for the space flight of Alan Shepard, the first American in space, in 1959. She also calculated the launch window for his 1961 Mercury mission. ... In 1962, when NASA used electronic computers for the first time to calculate John Glenn's orbit around Earth, officials called on her to verify the computer's numbers.
The movie is in fact based on the book of the same name by Margot Lee Shetterly, which is available for pre-order now. (It should be published early September.) Shetterly won a Sloan Fellowship in 2014 for work on the book.
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Currently at the International Congress of Chinese Mathematicians. I have never been to so "organized" a conference. Entrance to events are strictly patrolled by ushers checking the colors of the lanyard of you name badge. The honored guests with red lanyards are not allowed to hide in the crowd and are directed to always sit in the first two rows.
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It has been a really long time since I looked at the Physics StackExchange, being somewhat disappointed by the average (as of a few years ago) quality of the questions and answers.
Today however I stumbled across a gem!
Today however I stumbled across a gem!
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Continuing on my previous post: I've retrofitted one of my recent papers (http://arxiv.org/abs/1601.01303v1 to be exact) to show how a cross reference visualization would look "in the wild".
... and it is a lot wilder than I expected.
Because of that, I added some code to, whenever possible, do some automatic compression/collation of nodes. It is of limited effectiveness since the writing of the original paper was not done with this software in mind. I am also not sure whether this is a useful feature, since it reduced the number of nodes, but at the expense of increasing a bit the density of the graph (the reduction in the number of edges is not proportional to the reduction of number of nodes). It is not clear whether the condensed graph is more readable. (You can see that version http://users.math.msu.edu/users/wongwwy/testd3/shocks-demo-condensed.html).
Also, +Ian Agol, this paper is only 1/5 of the length of a Christodoulou opus. I don't know how big a screen would be required to actually visualize those.
(I am now somewhat curious about the typical complexity of cross references within a paper, especially how it scales with length; one expect nodes to grow more or less linearly, but what about edges? This is probably something that can be experimentally found by analyzing TeX sources from arXiv.)
... and it is a lot wilder than I expected.
Because of that, I added some code to, whenever possible, do some automatic compression/collation of nodes. It is of limited effectiveness since the writing of the original paper was not done with this software in mind. I am also not sure whether this is a useful feature, since it reduced the number of nodes, but at the expense of increasing a bit the density of the graph (the reduction in the number of edges is not proportional to the reduction of number of nodes). It is not clear whether the condensed graph is more readable. (You can see that version http://users.math.msu.edu/users/wongwwy/testd3/shocks-demo-condensed.html).
Also, +Ian Agol, this paper is only 1/5 of the length of a Christodoulou opus. I don't know how big a screen would be required to actually visualize those.
(I am now somewhat curious about the typical complexity of cross references within a paper, especially how it scales with length; one expect nodes to grow more or less linearly, but what about edges? This is probably something that can be experimentally found by analyzing TeX sources from arXiv.)
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For +Susannah Dorfman as there are a few familiar names on that paper.
Satanic crystal found in ancient meteorite
Just kidding! There's nothing devilish about the pentagram here. It's what scientists saw when they shot X-rays through a tiny piece of a meteorite found in the far northeast of Russia.
No ordinary crystal can produce this pattern - it takes a quasicrystal, where the atoms are packed in a way that never quite repeats. Scientists have made lots of quasicrystals in the lab, but only two have been found in nature, both in meteorites!
This is the second one. It contains a mineral called icosahedrite, made of aluminum, copper and iron. It's only stable at high temperatures and pressures, so it must have formed in a collision. It's been slowly decaying ever since, but very slowly. It could be billions of years old.
To see how this mineral could have formed, scientists simulated the collision between two asteroids in their lab. They took thin slices of minerals found in the Khatyrka meteorite and sandwiched them together in a gadget that looks like a a steel hockey puck. They attached it to the muzzle of a four-meter-long gun and blasted it with a projectile moving nearly one kilometer per second!
Yup. Icosahedrite.
For details and more pictures, see:
• Paul D. Asimow, Chaney Lin, Luca Bindi, Chi Ma, Oliver Tschauner, Lincoln S. Hollister and Paul J. Steinhardt, Shock synthesis of quasicrystals with implications for their origin in asteroid collisions, Proceedings of the National Academy of Sciences 113 (2016), 7077-7081. Freely available at http://authors.library.caltech.edu/67876/
Puzzle: how did pentagrams get associated with Satan in the first place?
#astronomy #geometry
#spnetwork DOI:10.1073/pnas.1600321113
Just kidding! There's nothing devilish about the pentagram here. It's what scientists saw when they shot X-rays through a tiny piece of a meteorite found in the far northeast of Russia.
No ordinary crystal can produce this pattern - it takes a quasicrystal, where the atoms are packed in a way that never quite repeats. Scientists have made lots of quasicrystals in the lab, but only two have been found in nature, both in meteorites!
This is the second one. It contains a mineral called icosahedrite, made of aluminum, copper and iron. It's only stable at high temperatures and pressures, so it must have formed in a collision. It's been slowly decaying ever since, but very slowly. It could be billions of years old.
To see how this mineral could have formed, scientists simulated the collision between two asteroids in their lab. They took thin slices of minerals found in the Khatyrka meteorite and sandwiched them together in a gadget that looks like a a steel hockey puck. They attached it to the muzzle of a four-meter-long gun and blasted it with a projectile moving nearly one kilometer per second!
Yup. Icosahedrite.
For details and more pictures, see:
• Paul D. Asimow, Chaney Lin, Luca Bindi, Chi Ma, Oliver Tschauner, Lincoln S. Hollister and Paul J. Steinhardt, Shock synthesis of quasicrystals with implications for their origin in asteroid collisions, Proceedings of the National Academy of Sciences 113 (2016), 7077-7081. Freely available at http://authors.library.caltech.edu/67876/
Puzzle: how did pentagrams get associated with Satan in the first place?
#astronomy #geometry
#spnetwork DOI:10.1073/pnas.1600321113
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Signal boost, also, a reminder to self.
Mathematical Reviews and zbMATH ask for your feedback to revise the MSC classification scheme. More info at http://msc2020.org.
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Shared with no comment, beside that there are some rather interesting anecdotes buried in the discussions.
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