Artemis Racing sailor Andrew Simpson dies in training accident -
It is with immense sadness that Artemis Racing confirms the tragic death of crewmember Andrew “Bart” Simpson today in San Francisco. Our heartfelt condolences are with Andrew’s wife and family.
Station’s power relies on ammonia coolant. A few hours ago, we determined that the ammonia was leaking out of the Station and into space. At the analyzed rate, one of the Station’s cooling loops could shut down within 48 hours.
It is a serious situation, but between crew and experts on the ground, it appears to have been stabilized. Tomorrow we find out for certain.
by Bob Carpenter
Stan 1.2.0 and RStan 1.2.0 are now available for download: http://mc-stan.org/
Highlights after the jump.
Karma loves playing ball: Our animal caregivers found a new toy for the octopus. And she loves it.
It's Okay To Be Smart: This GIF might break your brain a little: -
Take a look at the sequence of images below (I recommend clicking through to enlarge, Tumblr Dashboard folks). Works best if you stare at the dot:
Color? Or black and white?
The rods and cones of your retina respond to the illumination (black-white) and color of a scene, respectively….
Rogueleaderr: How to notify/email yourself when an EC2 instance terminates -
I make pretty heavy use of EC2 spot instances, which as you know can terminate at any time with no warning.
In order to get my spots back up ASAP, I’d like be notified when they terminate…
This looks super useful.
Line integral of a scalar field
This animation of mine is today’s Picture of the Day on Wikimedia Commons and several Wikipedia languages.
A scalar field has a value associated to each point in space. Examples of scalar fields are height, temperature or pressure maps. In a two-dimensional field, the value at each point can be thought of as a height of a surface embedded in three dimensions. The line integral of a curve along this scalar field is equivalent to the area under a curve traced over the surface defined by the field.
In this animation, all these processes are represented step-by-step, directly linking the concept of the line integral over a scalar field to the representation of integrals familiar to students, as the area under a simpler curve. A breakdown of the steps:
- The color-coded scalar field f and a curve C are shown. The curve C starts at a and ends at b
- The field is rotated in 3D to illustrate how the scalar field describes a surface. The curve C, in blue, is now shown along this surface. This shows how at each point in the curve, a scalar value (the height) can be associated.
- The curve is projected onto the plane XY (in gray), giving us the red curve, which is exactly the curve C as seen from above in the beginning. This is red curve is the curve in which the line integral is performed. The distances from the projected curve (red) to the curve along the surface (blue) describes a “curtain” surface (in blue).
- The graph is rotated to face the curve from a better angle
- The projected curve is rectified (made straight), and the same transformation follows on the blue curve, along the surface. This shows how the line integral is applied to the arc length of the given curve
- The graph is rotated so we view the blue surface defined by both curves face on
- This final view illustrates the line integral as the familiar integral of a function, whose value is the “signed area” between the X axis (the red curve, now a straight line) and the blue curve (which gives the value of the scalar field at each point). Thus, we conclude that the two integrals are the same, illustrating the concept of a line integral on a scalar field in an intuitive way.
I love wikipedia! It has really good and complete entries. And the most important, entries related to almost everything interesting.
For example… just five minutes ago I didn’t know that brain regulates the breathing frequency only by the blood’s carbon dioxide concentration readings that the brainstem makes and adjusting our need to breath in that basis.
When we feel the urgent need to breath, it’s due to the CO2 levels are increasing,not because we are running out of oxygen in blood. That’s quite interesting!
Here in the picture there are two graphics about the diving and normal breathing time, in two different situations. Practising and not practising induced hypocapnia. Hypocapnia is when blood CO2 are abnormally low. That provokes vasoconstriction in brain and consequently brain hypoxia, (really dangerous!)
The wiki’s article talks about some swimmers and freedivers using hyperventilation to induce themselves hypocapnia and postponing the incoming need to breath while diving, and allow them to dive for more time.
But, hyperventilation doesn’t increase the O2 levels, in fact, it makes them decrease a little, so practising doesnt’ represents any advantatge to the brain, and underwater blackout and drowning can easily happen in hypocapnia conditons.
Be aware of that!
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Hey! My book is on sale. Buy it.
This is a useful and heartening book for any data wrangler.
Solar System Sampler
In the 17th, 18th, and 19th centuries, girls in the UK and the US used needle and thread to embroider images and text onto pieces of fabric that were called “samplers.” Samplers, which could be quite intricate, were meant to promote basic literacy and to teach patience and carefulness.
Unlike many samplers, which featured botanical, Biblical, or domestic themes, this unusual pre-printed fabric from 1811 depicts a surprisingly scientific subject: the arrangement of the solar system. (via Slate)
The Great Comet of 1811, formally designated C/1811 F1, is a comet that was visible to the naked eye for around 260 days, a record it held until the appearance of Comet Hale-Bopp in 1997. In October 1811, at its brightest, it displayed an apparent magnitude of 0, with an easily visible coma. (via Wikipedia,)
More fuel for our science embroidery obsession.
I’m with you on the science embroidery obsession, Radiolab.
We’ve got embroidery! We’ve got knitting! And we’ve got adorable stitch art!
The passage at the top of the (unfinished) embroidery is the most interesting part. It’s from Milton’s Paradise Lost, and reminds us that there was once a time when scientific education had to be framed in the light of morality and “thy Glorious Works”, as it’s put above. ‘Twas a different time, eh?