Mind tricks may help arthritic pain
“We were giving her a practical demonstration of illusory finger stretching when she announced, ‘My finger doesn’t hurt any more’, and asked whether she could take the machine home with her. We were just stunned – I don’t know who was more surprised, her or us.”
I wonder how closely this is related to the phantom pain solution of amputees
TMI: Fear, Fukushima and Facts
A critique of the xkcd radiation dose chart I linked to, with some more details and caveats, some of which I recognize as true from by background (but wasn’t going to post on my own because it’s too far away from my areas of competence). Randall’s shortcoming is the mixing of chronic and acute exposure doses (long-term and short-term), which are not equivalent, i.e. a dose spread out over a period of time (e.g. months) does not have the same biological effect of the same dose that happens in a period of minutes or hours or days. Giving the body a chance to repair itself matters.
Understating the risks is just as irresponsible as overstating it.
The Mind of Dr. Pion: Don’t believe what the press is telling you!
There is no explicit by-line on this article, but the video contains an interview with BBC reporter Chris Hogg in Tokyo that repeats that a half life of 8 days means “that after 8 days the risk will have dissipated”.
The reporter is WRONG. Twice, because that is also not what the officials said. His ignorance of basic physics, in this case a topic I always teach in a college general education class, led him to misinterpret what was actually said by a government spokesman and hence mislead the public.
Stock tip: invest in adult diaper companies, what with the soiling of undergarments going on about radiation levels in the US.
I’ve run across a number of stories about the worries and the run on iodine tablets, and then saw the California radiation monitoring map which led me to the EPA site. They give radiation levels for select cities, but don’t tell you what the expected background levels are, so all you have is the assurance that the detected levels are small. However, the EPA has set up a section dedicated to the Japan accident, which includes a map with the most recent data for all of their monitoring sites. I eventually found how to get historical data — you click on “Query View” over in the left column — and looked to see what I could find.
I chose Eureka, CA because it’s on the West Coast and I was excited to have found the database, and the beta count rate because that would be indicative of having fallout reach the US; many fission products are beta-emitters. (The gamma data is divided into energy bins, and would have taken longer to analyze.)
Here’s what the radiation levels look like, starting with March 10, up through a half-day’s worth of data on the 25th.
The earthquake happened in Japan on the 11th at 0542 UTC. You might think the first spike, on the 11th, might be caused by the quake/tsunami, but the cooling problems didn’t happen until about 8 hours had elapsed and it would take several days for any fallout to reach California. If you really think that either peak is significant, all you have to do is go into the database and look at a larger data set.
This graph goes back to early February. The two peaks shown on the first graph are near points 750 and 1000. We can see that the radiation levels are showing no unusual behavior.
Because the EPA has labeled levels coming from specific isotopes I have to assume that’s by looking at the spectrum, and they give numbers that are much less than a picoCurie per cubic meter. One Curie is 3.7 x 10^10 decays per second (based on the activity of a gram of Radium-226), which means that a picoCurie is about 2 decays per minute. The EPA isn’t clear that the numbers it gives for gross beta counts are for a cubic meter or a larger volume, but I think it has to be, because 0.0017 pCi (the Anaheim Cs-137 activity) is only about a quarter of a decay per hour, so I imagine they sample a much larger volume.
Vocabulary lesson: many MSM stories are confusing radiation and fallout/contamination. radiation (in this context) is the energetic particle emitted when something decays, e.g. a gamma or a beta. Fallout or contamination refers to the radioactive particles, such as particulate matter that was expelled from the reactor and contains radioactive particles. We aren’t worried about radiation reaching us from Japan, because that is diminished by distance. It would be like complaining that the lights of Tokyo are too bright and though I’m sure Sarah Palin can see them from her home, it’s simply not an issue for us. What matters is the amount of radioactive particles that might reach us, and decay when they are here. But we can’t see any effect on the radiation levels, because any increase is small compared to the background and fluctuations in the background.
To quote Hedley LaMarr, “Gentlemen, Please, Rest Your Sphincters!”
Dr. Fritz Kahn’s illustration of the body as a machine: Der Mensch als Industriepalast (Man as Industrial Palace)
A Mystery: Why Can’t We Walk Straight?
More like building a mystery*. Perhaps I am missing something, but I’m having a hard time understanding the “mystery” behind this. From a physics standpoint, we know that a moving object will travel at constant speed in a straight line if and only if there is no net force acting on it. Forces along that path will change the speed, so we don’t have to worry about that, and vertical forces can be ignored, since we aren’t going to start levitating or submersing ourselves in the ground. Which leaves us with the last component, which is perpendicular to the path. An acceleration perpendicular to the path gives you — ta da — circular motion. Physics 101.
I’m guessing the problem is in the assumption that the human brain could remove all biases in our locomotion and produce only forces along the direction of travel, without visual cues for feedback. Why would you assume that to be true? The surprise might be that there are biases rather than fluctuations, which would lead to a random walk (in the perpendicular component), but that’s still not a straight line. Assuming no noise processes at all is just naive.
*no data on if this effect holds while wearing sandals in the snow
You either need to learn about the concepts of thermodynamics, or you can watch A Christmas Story
Boy’s Tongue Stuck to Frozen Pole After ‘Christmas Story’ Dare
You’ve seen this scene before — every Christmas.
An 8-year-old Oklahoma boy got his tongue stuck on a frozen stop sign pole after his brother dared him to lick it.
No mention of an escalation from a double-dog to a triple-dog dare, however.
So I’m at ScienceOnline 2011 for the weekend; I drove down Thursday, checked in and apparently missed DrSkyskull in the lobby when I went to the bar to get dinner. And then I collapsed. As I write this Friday morning I’m skipping the tours because I knew I wouldn’t be up to it; I went to the gym instead, figuring that would help me shake off my travel hangover.
The elliptical was a really fast track. Insanely fast, as compared to the one I use at work. I know that the one at work might not be calibrated properly, but I find it curious that the one at the hotel was indicating at least 10% faster than what I’ve been doing the past week. The exercise room is located next to the pool, so the air is warm and humid (somewhat less so than normal because it’s cold outside, and the window condenses a bunch of water) and that promotes sweat. Profuse sweat doesn’t help keep you cool, but it can make you feel like you’re doing really well in your workout. And the scale was reading ~3 lbs lighter than the scales at work and at the doctor’s office.
I wonder if it’s deliberate. It gives you positive feedback on your workout and makes you feel good about it, especially if you might not be at the top of your game from being on the road. Gives you a good mental association with the hotel. I read stories about how much effort goes into the psychology of casinos and all the tricks they employ, so it doesn’t seem out of the realm of possibility that someone’s gaming the exercise equipment to get a tiny edge in getting repeat business.
Or maybe it’s all about having little to think about on the machine, I had an awesome workout, and I can have the chocolate cake for dessert.
BA review: The Spyder III Arctic Blue laser from Wicked Lasers
But the blue lasers… I’ve heard about them. The brightness of a laser depends mostly on the power used*. A typical red laser might have a power of about 5 milliWatts (5 mW). My green one has a power of roughly 160 mW, which is a lot more than the red one. The blue one, though, has a power of 1250 milliWatts, nearly 8 times that of the green one!
So yeah, I wanted to try one out.
…
* Color is the next biggest factor, since our eyes are much more sensitive to green light than blue, or even red. Beam focus is another factor, and so on.
(edit: post seems to have disappeared. Erased from existence, using far less than 1.21 GW. Here is a copy of it from an aggregator site)
Thoughts:
More than a Watt of laser power in a handheld device? Damn dangerous. I agree, this is almost like having a gun in terms of safety & handling issues. The potential damage that could occur through stupidity and carelessness is significant. It comes with safety goggles, which not everyone will use, and even if Luke is wearing his blast shield while he waves his light-saber around, what about everyone else? I see trouble a’brewing.
The BA (sort of) underplays the significance of color. Color, or more specifically, wavelength, is in fact a huge factor in how bright a laser appears. In the early days of green lasers being available, they used some shady advertising tricks to exploit this by telling you the green laser was as bright as a red laser of a certain power, typically 5 mW. But in the fine print you found that the green laser had less than a milliWatt of actual output they were leveraging the fact that the sensitivity near 550 nm is more than five times the sensitivity out past 650 nm. So the BA has rigged the answer a little by using large difference in power. A green laser is going to look brighter than a red laser that has twice the power.
I suspect that one of the issues here is that the eye’s sensitivity is usually portrayed on a linear scale, like here (fig 154), which shows the photopic (light-adjusted) sensitivity ranging from 400 nm out to 700 nm, which is the usually-cited range. Notice that scotopic, or dark-adjusted vision really kills the sensitivity to the red, which is a killer in an optics lab using red lasers. Turning off the lights has a smaller effect in one’s ability to detect a spot because of the loss in sensitivity fighting the reduction in background.
But the effect isn’t best portrayed on a linear scale, because you can still detect photons beyond those boundaries, and the linear scale doesn’t give this impression. If you look at it on a log scale, you see that while the photopic vision has a shoulder near 700 nm, it doesn’t stay flat. You can see light out near 800 nm (we use a lot of 780 nm in the lab, for Rubidium, and you can see diffuse reflections from a few-mW source), but your eye is a million times less sensitive to it than to green light. Put another way, if you see even dim light in the near-infrared (NIR), it’s fairly powerful. I once saw a spot from a misaligned 852 nm laser (used for trapping Cesium), which was disconcerting, because it must have been really, really fracking powerful.
One might cut the BA some slack, because my examples aren’t laser pointers, and while he said lasers, he probably meant laser pointer and was thinking of only those wavelengths — color kind of restricting one to the 400nm-700 nm range — rather than what one might find in a lab. And they don’t make laser pointers in the IR, because what would be the point? Right? Well, not so fast. Green laser pointers are commonly made from pumped, frequency-doubled IR light, and this arrangement can let a lot of the IR through if there is no filter, and there may not be one. So you can get a blast of 808 nm light from the pump, and 1064 nm from the beam that doesn’t get doubled to 532 nm. While often the bright green light would trigger a blink to help save your eyes, it’s possible that it won’t, because light that has refracted or diffracted (phenomena which depend on wavelength) won’t line up anymore. You could potentially get an eyeful of IR, while the green spot doesn’t hit your eye. By the time you notice a problem, it will likely be because retinal damage has already been done.
So color is a big deal in how bright something appears. Let’s be careful out there.
It’s all about the energy balance
Twinkie diet helps nutrition professor lose 27 pounds
His premise: That in weight loss, pure calorie counting is what matters most — not the nutritional value of the food.
The premise held up: On his “convenience store diet,” he shed 27 pounds in two months.
For a class project, Haub limited himself to less than 1,800 calories a day. A man of Haub’s pre-dieting size usually consumes about 2,600 calories daily. So he followed a basic principle of weight loss: He consumed significantly fewer calories than he burned.
His body mass index went from 28.8, considered overweight, to 24.9, which is normal. He now weighs 174 pounds.
2/3 of his calories from junk food. He improved his cholesterol, too.
Why use a black body radiator as a standard, when no such thing exists?
It turns out that black body radiation provides us with a set of very precise working equations that relate the temperature of an object to the light it emits. Working from the ideal and using Planck”s law, we can predict the energy distribution across the spectrum for a given temperature. The total emitted power is calculated using the Stefan-Boltzmann law. The wavelength of the peak emission, and hence the color that dominates for this temperature, is provided by Wien’s displacement law. Knowing the ideal case allows us to predict or calculate actual values by correcting for the imperfections of actual hot objects.
h/t to ewmon
… and Titanium foamy goodness. Titanium foam is just as flexible and rigid as real human bone
The secret behind the new titanium foam implants is a foam-like structure that resembles spongiosa inside human bones, and a powder metallurgy-based molding process that consists of open-cell polyurethane (PU) foams being saturated with a solution that contains a binding medium and a fine titanium powder. The powder adheres to the foams cellular structures, and the binding agents and the PU are vaporized. The end result is a “semblance of the foam structures, which is ultimately sintered.”
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