linkstream2 microblog

The Magnetohydrodynamic Drive Is Real – & You Can Build One
https://www.Wired.com/story/the-magnetohydrodynamic-drive-is-realand-you-can-build-one/ Great illustration of the cross product & the weird way #magnetism makes things curl around

QT:{{”
“In the diagram, I have a magnet with the north side pointing down. This produces a magnetic field that also mostly points down (as indicated by the red arrow). Now for the awesome physics part. If you have an electric charge moving in a magnetic field, there is a force on that charge—the magnitude of this force depends on the strength of the magnetic field, the value of the electric charge, and the velocity of the charge. This magnetic force can be expressed as the following equation:

If don’t have a degree in physics, there are three things that are crazy about this equation. First, there is this weird arrow symbol over some of the variables. Nothing to be alarmed about—this just means these are vector quantities so that the direction also matters. Next there is this vector B. This represents the value of the magnetic field. Honestly, I’m not sure why we (physicists) always use B for the magnetic field—but we do. Lastly, there is that big “X”. That is not the sign for multiplication, that is the sign for the cross product. I guess I should also point out that “q” is the symbol for the electric charge.”

“}}

https://www.wired.com/story/the-magnetohydrodynamic-drive-is-realand-you-can-build-one/?mbid=social_twitter

https://mobile.nytimes.com/2018/01/17/arts/google-art-selfies-doppelgangers.html?referer=https://www.google.com/

Meet Your Art Twin: A 400-Year-Old With an Oily Complexion

https://www.newscientist.com/article/mg23731600-900-does-a-good-workout-mean-sweat/?cmpid=SOC%7cNSNS%7c2017-Echobox&utm_campaign=Echobox&utm_medium=Social&utm_source=Twitter#link_time=1516644513

https://medicine.yale.edu/intmed/residency/traditional/interview/YNHHWalkingMap_2015_09_20_16_277413_284_39363_v1.pdf https://www.ynhh.org/locations/ynhh-walking-maps.aspx

https://www.forbes.com/sites/stevensalzberg/2018/01/21/this-years-flu-is-nasty-and-getting-worse-and-now-weve-shut-down-the-cdc/#19d0c2a91144

Understanding the Brain: The Neurobiology of Everyday Life
https://www.coursera.org/learn/neurobiology

NYC’s Bold, Flawed Attempt to Make #Algorithms Accountable
https://www.NewYorker.com/tech/elements/new-york-citys-bold-flawed-attempt-to-make-algorithms-accountable QT: “#NYC should commit to demanding openness in all future contracts with vendors of these algorithmic services…It’s a dereliction of duty to allow vital decisions to be made by a black box.”

QT:{{”
“Frank Pasquale,… told me much the same. “While the terms of past contracts are hard to revisit, New York City should commit to demanding openness in all future contracts with venders of these algorithmic services,” he said. “They have the leverage here, not the firms. Secrecy may incentivize tiny gains in efficiency, but those are not worth the erosion of legitimacy and public confidence in government. It’s a dereliction of duty to allow vital decisions to be made by a black box.”
…
Cathy O’Neil, the author of “Weapons of Math Destruction: How Big Data Increases Inequality and Threatens Democracy,” told me. “What we’re finding is that the world of algorithms is one ugly wormhole.” In insulating algorithms and their creators from public scrutiny, rather than responding to civic concerns about bias and discrimination, the existing system “propagates the myth that those algorithms are objective and fair,” O’Neil said. “There’s no reason to believe either.””

Facebook Job Ads Raise Concerns About Age Discrimination
https://www.NYTimes.com/2017/12/20/business/facebook-job-ads.html QT: “The ability of advertisers to deliver…message to the precise audience most likely to respond is the cornerstone of
$FB…[but]…opportunities only to certain age groups has raised concerns”.

QT:{{”
“The ability of advertisers to deliver their message to the precise audience most likely to respond is the cornerstone of Facebook’s business model. But using the system to expose job opportunities only to certain age groups has raised concerns about fairness to older workers.

Several experts questioned whether the practice is in keeping with the federal Age Discrimination in Employment Act of 1967, which prohibits bias against people 40 or older in hiring or employment.”
“}}

At the Solstice, in Praise of Darkness
https://www.NYTimes.com/2017/12/16/opinion/sunday/solstice-praise-for-darkness.html QT: “Imagine a…movie…[capturing] the position of the setting sun…throughout the yr….[the sun] would migrate…betw its southernmost & northernmost positions on the horizon [&]…slow down toward the extremes.”

QT:{{”
“When this cycle was first explained to me as a child, my teacher advised me to imagine the “leaning” Earth as it arcs through its annual orbit around the sun….But such
illustrations, however useful, make it easy to overlook the loveliest aspect of this Thursday: that a solstice is in fact a moment of rest.

What stops at the December solstice is the sun’s apparent southward and night-lengthening (or night-shortening, in the Southern
Hemisphere) march across the sky. The true meaning of “solstice” — indeed, the word’s Latin roots refer to the stilling of the sun — was made clear to me by George Greenstein…He asked me to imagine a continuous movie composed of photographs that capture the position of the setting sun (the rising sun would work equally well) throughout the year.

In this movie…the setting sun would migrate back and forth between its southernmost and northernmost positions on the horizon. The sun would accelerate toward the middle of its journey (around spring and autumn, when the lengths of the day and the night change most quickly) and slow down toward the extremes. Once the sun reached an endpoint, it would at last come to rest — as it will on Thursday — before its motion reversed.
“}}