## Archive for the 'Body' Category

### Goldilocks and the Laser Pointer

Most Laser Pointers Are Too Strong

This seems a little … unfinished.

Neither the story nor the referenced study mention if the lasers are all supposed to be 5 mW and thus class IIIa (or 3R), or if, as one link claims, there are higher-power lasers that aren’t limited by this threshold because they aren’t marketed as laser pointers. Or if the violation isn’t that they are claiming 5 mW and exceeding it, but rather they are incorrectly (and presumably illegally) calling the more powerful devices laser pointers and listing them as class III/3R.

Green lasers use a shorter wavelength of light than red ones, making them brighter and more dangerous.

This was lifted from the included link, but lacking the detail found in another link. Green lasers aren’t brighter simply because they have a shorter wavelength. If that were true, a blue laser would be brighter still, and they aren’t. In fact green lasers must fire fewer photons per second at you than red lasers do, if they all have the same power. What makes the green brighter is your eye. The eye’s response to light isn’t constant across the spectrum — it’s much better at absorbing (and thus detecting) green light then either red or blue, so the green light has a better chance at doing damage.

### Seeing Red. Or the Opposite.

Why Do Doctors Wear Green Or Blue Scrubs?

Green could help physicians see better for two reasons. First, looking at blue or green can refresh a doctor’s vision of red things, including the bloody innards of a patient during surgery. The brain interprets colors relative to each other. If a surgeon stares at something that’s red and pink, he becomes desensitized to it. The red signal in the brain actually fades, which could make it harder to see the nuances of the human body. Looking at something green from time to time can keep someone’s eyes more sensitive to variations in red

I’ve noticed the opposite effect in the lab; when I work with lasers I wear laser safety glasses, which block the wavelength being used, and for quite a while this has been in the NIR. The glasses block everything above ~650 nm, so the glasses look bluish-green and deprives your eyes of any red light. After taking them off, everything has a pink hue to it.

### Synaesthesia

Synaesthesia and savant syndrome: are we all superhuman?

“There are numerous different kinds of synaesthesia,” Professor Brogaard began. “One of the most common forms is grapheme-colour synaesthesia, which is where letters or numbers give rise to specific colours. There are people who have so-called mirror-touch synaesthesia who experience the feeling of being touched when they see other people being touched. There are others who see colours when they taste something and some people even see colours when they feel fear.”

### I Know What You Did Last Summer, Based on Isotopic Ratios in Your Hair and Fingernails

Stable Isotopes in Forensics

[L]et’s follow a raindrop from the Pacific Ocean to Saltair Sally’s strand of hair. When water evaporates from the ocean, the heavier molecules containing deuterium and tritium and oxygen-18 do not evaporate as readily and are left behind in greater numbers. As droplets gather into clouds and eventually fall as rain, the heavier molecules fall first. This means rainwater in regions closer to oceans and large lakes is isotopically enriched compared with regions farther inland. Isotope levels are again fractionated in drinking water depending on whether it is drawn from wells or reservoirs (lighter isotopes more easily evaporate from the surface of reservoirs). Currently, scientists are busily creating maps of various isotopes’ distributions to assist investigators.
If Saltair Sally had been in Salt Lake City in the weeks preceding her death, the hair closest to her scalp would reflect the isotopic signature of Salt Lake City’s local water supply. If she had been in, say, Seattle instead, her hair’s isotopic composition would be different, giving investigators a valuable clue.

### Coming Soon? To a CSI Near You

Pacemaker hacker says worm could possibly ‘commit mass murder’

There’s a conundrum of security vs access for medical devices that use WiFi access — you don’t want doctors being shut out because they don’t have the password, but no safeguards means that anyone can hack in and disrupt the hardware.

Besides reverse engineering a pacemaker to deliver a deadly shock from 30 – 50 feet away, he demonstrated how he could rewrite the devices’ onboard firmware. Jack also said it possible to upload malicious firmware to servers that would be capable of infecting pacemakers and ICDs. “We are potentially looking at a worm with the ability to commit mass murder,” Jack said. “It’s kind of scary.”

Can’t wait to see this as a TV plot, though.

### Let’s Drink Beer. For Science!

Glass Shape Influences Consumption Rate for Alcoholic Beverages

Participants were 60% slower to consume an alcoholic beverage from a straight glass compared to a curved glass. This effect was only observed for a full glass and not a half-full glass, and was not observed for a non-alcoholic beverage. Participants also misjudged the half-way point of a curved glass to a greater degree than that of a straight glass, and there was a trend towards a positive association between the degree of error and total drinking time.

Wait, degree of error increased with total drinking time? Nooooooooooo!

### It’s Always More Complicated Than You Think

Odds are you sometimes think about calories. They are among the most often counted things in the universe. When the calorie was originally conceived it was in the context of human work. More calories meant more capacity for work, more chemical fire with which to get the job done, coal in the human stove. Fat, it has been estimated, has nine calories per gram, carbohydrates and proteins just four; fiber is sometimes counted separately and gets awarded a piddling two. Every box of every food you have ever bought is labeled based on these estimates, too bad then that they are so often wrong.

### Everything Old is New Again

[R]egardless, the analysis has been done; lead remediation is still a screamingly good deal. Lead remains one of the most common and harmful pollutants in the country; it’s often present in old paint and settles into soil, particularly in urban areas. One comprehensive study concluded that “each dollar invested in lead paint hazard control results in a return of $17–$221.” And that study focused on current, laborious methods of lead remediation. As it happens, scientists have developed a new, cheaper method — mixing fish bones into soil (!) — to absorb lead and render it nontoxic. Pretty cool stuff. Imagine what more research and funding could do.

I’m hoping the anti-spending reflex can be excised from our politics and replaced by the recognition that investment is a good idea. When the return on the spending exceeds the spending, it is a wise thing to do.

The elimination of lead from gasoline is a paradigmatic triumph of American environmentalism. A danger to health was discovered by scientists. Public-health advocates and greens pushed and pushed for decades, often futilely, to get the government to take action. When EPA finally cranked up efforts to do something about it, the agency was viciously attacked. Industry shills said it was an agenda to control Americans’ lives, driven by scientists who wanted research money and a cabal of extreme environmentalists. They said there were no viable alternatives to lead and the regulations would raise gas prices and destroy the economy. They paid their own scientists to produce counter-evidence. They flooded politicians with money.

Gosh, sound familiar? The EPA prevailed, but these tactics no doubt delayed the result and increased the damage done.

### Is It Hot in Here, or is it Just the Army?

US military unveils non-lethal heat ray weapon

On-demand hot-flashes. The menopausotron unveiled!

The technology has attracted safety concerns possibly because the beam is often confused with the microwaves commonly used by consumers to rapidly heat food.

“There are a lot of misperceptions out there,” lamented Taffola, saying the Pentagon was keen to make clear what the weapon is, and what it is not.

The frequency of the blast makes all the difference for actual injury as opposed to extreme discomfort, stressed Stephanie Miller, who measured the system’s radio frequency bioeffects at the Air Force Research Laboratory.

The system ray is 95 gigahertz, a frequency “absorbed very superficially,” said Miller.

The beam only goes 1/64th of an inch (0.4 millimeter), which “gives a lot more safety.”

In other words, the heating is all at the surface, not in the interior, so it cooks your skin, not your internal organs. It’s not a direct quote, but one might get the impression that the message is “it’s not microwave, it’s radio-frequency” and playing on the notion that radios are harmless. But AM and FM radio bands are at around 1 MHz and 100 MHz, respectively. However, ~ 1 GHz from microwave ovens is microwave, so 95 GHz is well into the microwave band of the spectrum.

### You Can’t Get There From Here

Taking the Plunge

Q. If I find myself in a free-falling elevator, is there any position that might increase my chance of survival? (Climbing on top of other people is not an acceptable answer.)

A. The best option would be to lie on your back on the floor as flat as possible, said Eliot H. Frank, a research engineer at the Center for Biomedical Engineering at the Massachusetts Institute of Technology.

Yes, that makes sense, but how does one get to the floor and lie flat, while in free-fall?

### The Best Insults

… are math insults. (SMBC)

### The Boy with the Electrical Dragon Tattoo

Meet Winston Kemp, Lightning Strike Survivor and Lichtenberg Figure Owner

We’ve all heard stories about people getting struck by lightning — usually as some sort of cautionary tale, but how many of us have ever seen the effects of lightning on a human? Winston Kemp, a 24 year old electrician, has had first-hand experience, and now he also has a unique and possibly permanent bit of body art to go along with it.

I have a Lichtenberg figure, which did not require me getting personally zapped.