"The effect shown in this clip is true for any object that has three different moments of inertia, e.g. as shown here for a prism. If you try to spin the object along two of its axes, it will spin in a smooth stable way, as shown here. In particular, these axes are the ones that have the highest and lowest moment of inertia. On the other hand, if you try to spin it around the axis with the intermediate moment of inertia, things get a bit chaotic. The reason is that any small perturbation (e.g. if you didn't throw it perfectly or if a whiff of wind blows) in the motion will cause the object to try to rotate about another axis of rotation as well. The net result is that you get the tumbling you see in the GIF. This effect is called the intermediate axis theorem, or the tennis racket theorem. In case you are interested in a more technical explanation, I posted a longer write-up here a while back."More discussion at the Wikipedia entry on the Tennis Racket Theorem and at the Educational GIFs subreddit source.
10 April 2018
Astronaut demonstrates rotational inertia
Relevant re Congress' questioning of Zuckerberg
They may be pelting him with softballs:
Members of the House and Senate committees that will question Facebook CEO Mark Zuckerberg about user privacy protection next week are also some of the biggest recipients of campaign contributions from Facebook employees directly and the political action committee funded by employees.
The congressional panel that got the most Facebook contributions is the House Energy and Commerce Committee, which announced Wednesday morning it would question Zuckerberg... Members of the committee, whose jurisdiction gives it regulatory power over Internet companies, received nearly $381,000 in contributions tied to Facebook since 2007, according to the Center for Responsive Politics. The center is a non-partisan, non-profit group that compiles and analyzes disclosures made to the Federal Election Commission.The second-highest total, $369,000, went to members of the Senate Commerce, Science and Transportation Committee, which announced later that it would have a joint hearing with the Senate Judiciary Committee to question Zuckerberg on Tuesday. Judiciary Committee members have received $235,000 in Facebook contributions...“Powerful interests provide lots of money to the committees that have jurisdiction over them, and they do it to gain influence with those members of Congress,” Wertheimer said. “It’s a fundamental problem that exists throughout the system and throughout the committee structure, and it undermines public confidence that the members are going to make decisions in the best interests of the American people.”Overall, Facebook has contributed $1.1 million to House members, split almost evenly between the parties...
More at USA Today. We all know how this bullshit system works. If candidate A is running against candidate B, instead of giving $20,000 to candidate A, a company gives $10,000 to A and $10,000 to B. Then, whichever one wins feels beholden to the corporation for its "support," which wasn't in fact support. It stinks to high heaven.
"Plus, nearly 30 members of Congress own Facebook stock, according to a story in Roll Call, including two Democratic members of the committee who will question Zuckerberg next week."
09 April 2018
"This might come in handy someday"
The perfect comic to send to a friend or relative with hoarding tendencies.
More Pearls Before Swine.
06 April 2018
Car with dashcam left at the dealership..
There are lots of stories about cars being taken on joy rides by service technicians, but this customer left his dashcam on and was able to document not just the frivolous "test drive" but the failure to provide service.
"Paid Over $700 for transmission service and it wasn’t even done! Car was on the Hoist for 11 minutes! And charges for Over 90 minutes labour!! "
'Qui ouvre une école, ferme une prison.'
The title is a quote from Victor Hugo: "Each time you open a new school, you shut down a prison."
Photo cropped for size and emphasis and brightened from the original here.
Snake
Jingtai County, Baiyin City, Gansu Province, China. This is a section of mountain road leading to the Yellow Stone Forest.
The photo is from a remarkable gallery posted at The Atlantic of winning entries in the Sony World Photography competition.
Credit © Li Wang, China, Commended, Open, Travel (Open competition), 2018 Sony World Photography Awards.
Adult cured of sickle-cell disease by stem cell transplant
The recipient was fortunate to have an HLA-perfect-match donor:
An Edmonton woman who received donor stem cells from her sister during a procedure in Calgary last year has been declared cured of her sickle-cell disease and health officials believe Revée Agyepong is the first adult in Canada to be cured of the disease through this method...Anyone who has ever seen a sickler in crisis, with excruciating pain in every bone in their body from no fault of their own, will appreciate what an absolutely awesome event this is. I have a family member who received stem cells to treat scleroderma, and spoke this week to a woman whose son received intraarticular stem cells to try to reverse degenerative arthritis. Macular degeneration, ALS, and other "incurable" diseases are being studied. Amazing.
“When Revée approached us, we had coincidentally been thinking about adult stem cell transplant for sickle-cell disease based on the remarkably good outcomes that Alberta Children’s Hospital has been seeing with transplants in the pediatric population,” explained Dr. Daly in a released statement. “She met all the necessary criteria in terms of being able to tolerate a transplant but, most important, she had a sibling who was a 100 per cent match.”
The procedure proved successful but there are concerns as her immune system will remain compromised as a result of the anti-rejection drugs. The side-effects are expected to persist for another year.
On Tuesday, blood tests confirmed the 26-year-old was sickle-cell disease free.
"Over the past few months, what we've seen is that Revée's sister's bone marrow has taken over the production of Revée's red blood cells," said Dr. Daly. "The amount of sickle-cell hemoglobin in her bloodstream has decreased almost to zero."
Bluebonnets
I lived in Texas for ten years, but never got to the Hill Country region while the bluebonnets were in bloom. This photo is too highly saturated for my taste, but there can be no doubt about the beauty and impressiveness of the spectacle. Years ago I was fortunate enough to visit Kew when the bluebells were blooming in profusion, and always loved the woodlands of central Kentucky carpeted with Blue-Eyed-Marys in the spring.
03 April 2018
Fishing nets
I didn't know what they were either, until I read a caption. Still don't know how they work...
Credit Yen Sin Wong/ Travel (Open competition) /2018 Sony World Photography Awards, via.
The first American tea
Cassina, or black drink, the caffeinated beverage of choice for indigenous North Americans, was brewed from a species of holly native to coastal areas from the Tidewater region of Virginia to the Gulf Coast of Texas. It was a valuable pre-Columbian commodity and widely traded. Recent analyses of residue left in shell cups from Cahokia, the monumental pre-Columbian city just outside modern-day St. Louis and far outside of cassina’s native range, indicate that it was being drunk there. The Spanish, French, and English all documented American Indians drinking cassina throughout the American South, and some early colonists drank it on a daily basis. They even exported it to Europe...For further discussion of the NON-emetic properties of the tea, see Atlas Obscura.
Upon export to Europe, cassina was marketed in England under the names “Carolina tea” and “South Sea tea,” and in France as “appalachina,” likely a reference to the Appalachee people.This confusing array of names emphasizes the practicality of the Linnaean classification system, which was still in its infancy when Europeans learned of cassina. William Aiton, an eminent British botanist and horticulturist, director of Kew Gardens, and “Gardener to His Majesty,” is credited with giving cassina the scientific name it bears to this day: Ilex vomitoria. Ilex is the genus commonly known as holly. Vomitoria roughly translates to “makes you vomit.”...
In the earliest days of the Southern colonies—when plantations were being carved out of woodland and luxury imports were rare—cassina drinking was widespread from slaves to plantation owners. But as plantations became larger and more profitable, the nouveau riche demonstrated their wealth by drinking expensive imported tea.
Biomimicry
One of these is a Peregrine falcon. The other is a B-2 bomber.
The peregrine falcon reaches faster speeds than any other animal on the planet when performing the stoop, which involves soaring to a great height and then diving steeply at speeds of over 320 km/h (200 mph), hitting one wing of its prey so as not to harm itself on impact. The air pressure from such a dive could possibly damage a bird's lungs, but small bony tubercles on a falcon's nostrils are theorized to guide the powerful airflow away from the nostrils, enabling the bird to breathe more easily while diving by reducing the change in air pressure. To protect their eyes, the falcons use their nictitating membranes (third eyelids) to spread tears and clear debris from their eyes while maintaining vision. A study testing the flight physics of an "ideal falcon" found a theoretical speed limit at 400 km/h (250 mph) for low-altitude flight and 625 km/h (388 mph) for high-altitude flight. In 2005, Ken Franklin recorded a falcon stooping at a top speed of 389 km/h (242 mph).Discussion of biomimetics/biomimicry here. Via.
Available
Best comment from the discussion thread:
"Alternating between upper and lower case and style...like a good ransom note."
The efficacy of sugar in wound healing
This is not new information, but the BBC has a nice brief review:
As a child growing up in poverty in the rural Eastern Highlands of Zimbabwe, Moses Murandu was used to having salt literally rubbed in his wounds when he fell and cut himself. On lucky days, though, his father had enough money to buy something which stung the boy much less than salt: sugar...Anyone who doubts that wounds can be difficult to treat has never seen a sacral decubitus ulcer that has burrowed down to the level of the vertebral bodies. I do hope that more attention is paid to non-antibiotic interventions.
To treat a wound with sugar, all you do, Murandu says, is pour the sugar on the wound and apply a bandage on top. The granules soak up any moisture that allows bacteria to thrive. Without the bacteria, the wound heals more quickly...
The sugar Murandu uses is the plain, granulated type you might use to sweeten your tea... he found that it worked for diabetics without sending their glucose levels soaring. “Sugar is sucrose – you need the enzyme sucrase to convert that into glucose,” he says. As sucrase is found within the body, it is only when the sugar is absorbed that it is converted. Applying it to the outside of the wound isn’t going to affect it in the same way...
McMichael, who works at the University of Illinois Veterinary Teaching Hospital, first started using both sugar and honey on pets back in 2002. She said it was a combination of the simplicity of the method and the low cost that attracted her – especially for pet owners who couldn’t afford the usual methods of bringing the animal to the hospital and using sedation.
McMichael says that they keep both sugar and honey in their surgery and often used it on dogs and cats (and occasionally on farm animals). Honey has similar healing properties to sugar (one study found it to be even more effective at inhibiting bacterial growth), though it is more expensive...
As well as being cheaper, sugar has another upside: as more and more antibiotics are used, we are becoming resistant to them.
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