Archive for December, 2014
In fact, what’s truly amazing about the work is that scientists are able to actually measure these very low levels of radiation at all — as well as to chemically fingerprint them and thereby prove that certain radioisotopes of the chemical element Cesium, which arise as a by-product of nuclear fission, actually arrived off of North American waters after traveling all the way from Fukushima.
The big non-news is that the radiation levels are small — hence the amazement at being able to measure them. But say “radiation” and some fraction of the population freaks right the hell out. So that’s the take-home message, even if there are a few subtle things missing in the story.
The activity (how radioactive a sample is, measured these days in Becquerels, or number of decays per second) is not the whole story, because not all radiation damages the body the same amount, and it matters greatly if the contamination accumulates in the body or not. Their example is swimming in the ocean, but I think people might also be concerned about eating fish, who would effectively be filtering out and accumulating radioactive material. Are they twice as radioactive as the water? Ten times? Is the internal dose more damaging than an external dose (that’s true of alpha and beta radiation)? Cs-137 is a beta emitter, and in humans it accumulates in the body, with a biological half-life of 70 days. So I imagine it accumulates in fish, as well. But with such low starting levels, probably not anything to worry about.
Another nit is with the picture down near the end, the “helpful figure from the Woods Hole Oceanographic Institution” is somewhat less helpful than it could be. First of all, it doesn’t have the Fukushima incident on it as a comparison. I’ve seen a few links, and their estimates vary by around an order of magnitude, but it’s between ~4 million and ~40 million curies of Iodine and Cesium into the atmosphere, and one link had an additional amount going into the water of half of the atmospheric discharge. So there’s your comparison. (A curie is 3.7 x 10^10 decays per second, as that
was Marie Curie’s favorite number is that activity of a gram of Ra-226. But it’s a huge number and not normally useful for everyday discussion — you are usually talking about picocuries or nanocuries, or something like that.)
Another nit is that comparing activities between different isotopes is a tad dicey, for a couple of reasons. The activity is a rate, not the total amount of potential dose. 1 curie of a contaminant that has a half-life of a day is very different than a curie of something else that has a half-life of a million years — in 10 days, the one-day half-life isotope is down to 0.1% of the activity (a millicurie), while the other is still basically the same. When you look at the Uranium and Potassium numbers on that infographic, keep in mind that K-40 has a half-life of 1.3 Billion years, and Uranium-238 is 4.5 Billion years. Their respective activities aren’t going to perceptibly change in the next 30 years, while any contaminant Cs-131 will drop in half. Further, Uranium is an alpha decayer, which is the most damaging internal source (though if it’s external is pretty harmless — an alpha won’t penetrate your clothes or through the dead layer of skin on your body). Uranium also decays through a chain of radioactive daughters, which have their own decays to contribute. So the activity doesn’t tell the whole story — the reason the ocean’s Uranium and Potassium aren’t a big issue is that the ocean is huge. Fukushima’s release was concentrated, but owing to time and dilution, it’s not a problem for those of us in the US.
During the 1980s and into the early 1990s, however, the auto industry did away with carburetors in favor of electronic fuel injection, which uses sensors to supply fuel to the engine and get the right air and fuel mix. This makes the problem of warming up the car before driving irrelevant, because the sensors monitor and adjust to temperature conditions.
Another big myth, at least based on how I’ve seen people drive, is that it’s a good idea to spin your tires to get traction. But since the coefficient of sliding friction is lower than that for static friction, once the slipping begins, you’ve lost. You should ease off the gas and start over.
My trip home for Christmas gave me my first shot at using my thermal IR camera in quasi-freezing conditions — it ended up being warmer than usual, but still dropped to freezing, or close to it, when the sun was down. I did a survey of my mom’s and a neighbor’s house (confirming for the neighbor that the section of roof where the snow melts fastest is warmer than the rest). Not surprisingly, the warmest parts were the windows, and we have lots of windows. The largest ones are now double- or triple-pane, so it used to be be worse.
Several basement windows, though, are still single-pane. The whole idea of insulation is to trap dead air, i.e. it won’t convect and it also conducts poorly, so I tried a little experiment: putting some bubble wrap up against the window, wrapped in some thin packing foam. I left a slice of it uncovered as a control.
You can see that the left side is noticeably warmer than the insulated part. I went online to see if anyone made insulation made specifically for glass, and ran across a site that had done pretty much what I did — just using two layers of large-bubble packing material so I went out and bought some. The basement windows are now no warmer than the rest of the cinder-block walls. The bubble wrap is translucent, so most of light still gets through.
I used the last of the wrap on some windows on the north side of the house, so I’m not blocking any incoming light that helps heat during the daytime. In my test, I blocked off one section
The window I tested is the one on the left. It’s slightly cooler than the rest. I used one of the other FLIR programs to confirm it’s about 1 ºF cooler than its neighbors (those pictures don’t get saved to the camera roll, though. Not sure why). These are multi-pane windows so the effect isn’t as dramatic, but every little bit helps, so I ended up covering up a few more windows to use up the bubble wrap I had bought. They’re in a part of the room that’s partly blocked anyway, so it doesn’t really impede looking out. This could be re-used from year to year (the basement windows probably left up permanently) and only took a few minutes to do.
I finally read a book that’s been in the queue. Devil in the Grove: Thurgood Marshall, the Groveland Boys, and the Dawn of a New America
As side note, I’ll mention that I heard about this right after the book won the Pulitzer last year and was alerted to a local-boy-makes-good story in one of the upstate NY papers, sent to me by my mom. The author (Gilbert King) and I were in the same graduating class in high school. That combination was enough of a nudge to get me to buy it.
It’s a horrific tale of the pervasiveness of racism in our not-too-distant past, and the involvement of Thurgood Marshall in the case allows for his compelling story to be told as well, along with others involved in the NAACP and its Legal Defense Fund (LDF). I had a little trouble keeping the large cast of characters straight, as the story jumps back and forth between the case and the history leading up to it, but I found it to be a captivating read. One gets a fairly raw look at the atmosphere of the times, including the reality that no person of color was likely to see justice done in any legal conflict that crossed the racial barrier — in a capital case such this, that the defendants would be found guilty was rarely in doubt, regardless of the facts, and it was considered a “victory” if the sentence came back as life in prison rather than the electric chair. The book tells of some truly heinous characters and lays out the LDF’s strategy of establishing grounds for appeal, because the only possibility for a result that came close to fair would only happen in courts far removed from the alleged crime.
It’s hard not to notice the similarities of this case with recent events in Ferguson, in New York, and elsewhere — that while some of the overt acts of violence stemming from racism have subsided — lynch mobs by people in sheets, as an example — far more behavior has only been masked and still pervades society. I’ll leave to others more eloquent than I to continue to delve in to commentary on all that, save for this: it’s too easy to say that things are better now than they were 60 years ago and leave it at that. To ignore it because for many of us it’s normally out of sight. To not believe the stories simply because we don’t experience it ourselves (a lot of parallels with sexual misconduct here as well). Social media has been a big step forward, as it has allowed for these events to be shared and not contained as a local, isolated incident. Maybe it can galvanize us enough to follow through to the next steps, to change the system and/or the people in the system, as necessary.
I’ve read that the rights to the book have been bought by Lionsgate, and they have given it a high priority. I hope this project doesn’t pull any punches. We got a glimpse of this kind of atmosphere in “Mississippi Burning”, including the collusion and overlap between law enforcement and the KKK, and “Devil in the Grove” shows us that the portrayal was not Hollywood embellishment. (It also shows the FBI wasn’t always so keen or successful in working civil rights cases — that transformation starts in the book’s span of history) There are a couple of story arcs in the book, where the attitudes of a few people are changed by their exposure to the hypocrisy of the situation and to the persuasiveness of Thurgood Marshall, which might lend themselves to some of Hollywood’s weaknesses (that can change “true story” into “based on a true story”). I say read the book — there is only so much a movie can include, anyway — and hope the movie doesn’t disappoint.
Seems to me that a lot of politicians are using “I am not a scientist” when they shouldn’t, and forgetting that fact when they should remember it.
Line-item science bashing by eyeballing titles and brief study descriptions is one of the most concerning consequences of the NIH budget crisis, and certain sciences will bear the brunt of the ridicule given accessibility of the topic. For example, we all have personal theories about nutrition and human behavior, but few of us have personal theories about DNA mutation or B cell development. The confidence that superficial knowledge creates amongst legislators and outspoken others has the potential to be devastating to science. Now more than ever, scientists and health care professionals need to be educating the public about the worth of our work.
The problem here is that the deficit model isn’t necessarily valid — if there’s an ideological bias at work then education won’t fix the problem. I think it’s less about false confidence and more about not liking research that might conclude something that runs afoul of one’s established world view. To paraphrase something I recently saw on twitter, these are people who want science to reinforce their beliefs. If it’s going to contradict those beliefs, they want to shut it down.
The article below said that, due to the rotation of the Earth gradually slowing down over time, this winter solstice would feature the longest night ever.
I got this wrong. The Earth’s rotation is gradually slowing on an extremely long timescale, but on a shorter year-to-year basis, geologic factors can alter the speed as well.
Right basic idea— the rotation rate is slowing as a long-term trend — but wrong execution.
This is pretty cool. Designing a tool on earth and 3D printing it on the ISS.
On the ISS this type of technology translates to lower costs for experiments, faster design iteration, and a safer, better experience for the crew members, who can use it to replace broken parts or create new tools on demand. But what I’m really excited about is the impact this could have on human space exploration beyond Earth orbit.
When we do set up the first human colonies on the moon, Mars and beyond, we won’t use rockets to bring along everything we need. We’ll build what we need there, when we need it.
That’s pretty much what I thought when I saw the headline. I know that there has been discussion of putting these on ships and boats, so that one can do certain repairs underway without having to carry a lot of different spare parts. If they can be printed, you only have to carry the stock. In space, all of those size and weight pressures are multiplied.
Faced with difficulties in applying fundamental theories to the observed Universe, some researchers called for a change in how theoretical physics is done. They began to argue — explicitly — that if a theory is sufficiently elegant and explanatory, it need not be tested experimentally, breaking with centuries of philosophical tradition of defining scientific knowledge as empirical. We disagree. As the philosopher of science Karl Popper argued: a theory must be falsifiable to be scientific.
Wow. Add me to the “disagree” list. This seems like it would be a huge step backward — like zapperz said, this is more like religion. We would have dogma, not science. It harkens back to the philosophy of old, before modern science. Heavier balls fall faster than lighter ones — that’s pretty elegant. Why bother testing it? Things move owing to their inherent nature. There are four
lights elements. The universe is in steady state. Galilean transforms and Euclidean space are pretty elegant, too. Too bad all of these are wrong, to varying degrees, because they disagree with nature — and that’s the requirement we have for all of science: it has to describe what actually happens in nature, and because we can be fooled by a great explanation, we have to know we’re getting it right. The article also points out the danger of a model that’s too vague, so that any result can be explained. Not a lot of scientific value in that.
What is the measure of elegance, anyway? Without falsifiability, there’s no way to know if you’re wrong. What if you have two competing theories — do they wrestle for it? Talent competition?
Do we really want to go there? I don’t think so.
If we consider “noon” to be the time at which the sun is highest in the sky then the time between successive noons is not quite 24 hours. Relative to our clock, our sundial will seem to run a bit fast on some days, and a bit slow on others. Because of this, if we note the position of the Sun at clock noon over the course of a year, it will mark out a figure-8 pattern known as an analemma.