You're using the most popular--but also narrowest--definition of chemo. Pull out your Merriam-Webster (online at www.m-w.com) and the first definition is a literal interpretation of the term:
chemotherapy: n. The use of chemical agents in the treatment or control of disease or mental illness
Brachytherapy is the implantation of radioactive sources into a tumour to kill them.
Brachytherapy is a blanket term is radiotherapy that covers a range of techniques to place radioactive sources in close proximity to a target volume within the body. It may include the use of sealed seeds (iodine-131 sealed in a casing is often used for prostate cancer) than can be permanently implanted. It also includes high dose rate therapies where wires within catheters or needles tipped with potent radioactive sources (ie iridium-192), are inserted into the body for a few minutes at a time, again to precisely deliver radiation to a controlled volume. The other broad branch of radiotherapy is teletherapy--external beam radiotherapy--which obviously doesn't apply in this case.
...do they have the ability to sort out the different forms and identify only those that are not naturally occuring?
The short answer is, yes!
Depending on the size of the sample, you can look at its spectrum of gamma radiation. Different radioisotopes emit gammas at different frequencies when they decay, providing a distinctive fingerprint.
High resolution mass spectrometry will also do it for you. I know a chemist who has tricks for detecting femtograms (1E-15) of an element (though his mass resolution isn't very good, you could see a very tiny amount of a transuranic element like plutonium.)
Really, all you need is to be able to quickly identify areas that are worth further investigation. If you find something that seems suspicious--even if it isn't conclusive--that tells you where to bring in the analytical big guns. Actually, that usually means a lot more cotton swabs.;)
Of particular note is that the NYT was *not* able to verify that anyone said they carrying a note from a doctor would be useful; rather, it said the police would not accept such a letter as "sole proof" that the person was not trying to pull a fast one on them, and would still conduct a full investigation.
If you read the linked New Scientist article in the post, or even the original JAMA letter, it states as much.
A letter like that is pretty easy to fake, and I imagine that most police officers don't have the medical physics training to assess that sort of document's veracity on the spot. The recommended letter should include (among other things) "...the physician's 24-hour telephone numbers to allow police to verify the content of the letters."
Really, if you're going to go to the trouble of stopping people who set off radiation alarms, it does make sense to check their stories before you send them on their way. Whether the detectors are at all worthwhile is still a matter worthy of debate.
Dumb question: How long does it take to die without a thyroid?
Actually, the whole point of the iodine treatment is to destroy part or all of an overactive thyroid. Afterwards, most of these people live quite happy, quite normal lives. Some of them need to take hormones to top up what the thyroid is no longer providing, but usually their lives are not significantly shortened.
Besides, if you're prepared to do surgery to implant radioisotopes for smuggling, you'd be better off putting it in your chest cavity somewhere. Most people just don't have a lot of free space in their necks.
If you're just interested in terror, you could carry a bottle of some powdered radioisotope. They're not really that hard to come by. Sprinkle it on the subway. Random subway cars, station benches, wherever.
Soon as the news hits that the New York subway system is contaminated with radioactive material, there will be panic, regardless of amount. And it wouldn't take a very big container of material to do it, either.
Tremendous amounts of fear; no bomb required. Remember when there was anthrax in the mail? You can scare a lot of people without any explosions.
Graves disease is a form of hyperthyroidism, in which the thyroid secretes excessive amounts of certain hormones. The treatment of Graves disease involves removal of part or all of the thyroid, chemical supression of hormone production, or destruction of the thyroid using radiation.
In the latter treatment, doctors take advantage of the fact that iodine is concentrated by the body in the thyroid gland. After dosing a patient with radioactive iodine-131 (in this case, 20 millicuries--a nontrivial amount) the iodine will accumulate rapidly in the thyroid. While it decays, it kills off most or all thyroid tissue without doing serious damage to the rest of the body. With a half-life of about eight days, the stuff remains detectable for quite a while.
So--what we've done is use the chemical properties of a material (I-131) to deliver radiation therapy. Presto! Chemotherapy that is also radiotherapy. Actually, I'd probably lean towards describing it as brachytherapy, just to make everyone happy.
...plus it's so easy to just delete an email, it's a lot more work to sort through physical mail and throw it out.
I realize that the parent poster is probably just playing devil's advocate--most likely with a healthy dose of sarcasm.
The important point is that the sender pays for the snail mail that I receive--when it comes to my door, I don't have to cough up for my letters, whether I want them or not. Email is a collect call, and one that you can't refuse to accept. Physical and electronic junk mail both waste my time, but spam costs me money.
Your forgot Friday, which deviates totally from the formula by making the main character a WOMAN who has exciting adventures, says witty things, is unbearably clever, outsmarts the bad guys, and has sex.
You're right; I did forget Friday. That said, at the end of the book, she still settles down on a colony world with her new life partner--a doctor--to start making babies. Go figure. I guess I'm impressed that Heinlein stretched himself a little bit.;)
Robert Heinlein is an excellent source of some delightful quotations. Others among my favourites include,
Anyone who cannot cope with mathematics is not fully human. At best he is a tolerable subhuman who has learned to wear shoes, bathe, and not make messes in the house.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
Alas, his books are not the deep, meaningful volumes they are usually represented to be. (Stranger in a Strange Land has its moments.) They're delightful stories and fun to read--I admit I often can't put them down. But they nearly all follow the same basic premise of attractive young woman (women, often) and dirty old man have exciting adventures, say witty things, are unbearably clever, outsmart the bad guys, then have sex (usually incestuous).
That said, I can see why the dirty old man sleeping with attractive and brilliant young woman has appeal on Slashdot.
Gee, if I wanted that, I'd dust off my C-64 and play. They built those things solidly...nearly two decades, and I've had to replace the power supply brick. And that's it. Granted, use has tapered off significantly over the last decade, and the joysticks that have suffered from heavy usage need replacement, but still...
There's something to be said for avoiding the hard drive as a point of failure.
It's not that SETI@Home is ignoring non-barycentric signals; they are just assigning barycentric signals a higher priority for examination.
This is a pretty reasonable approach, actually. Barycentric signals imply deliberate action. Further, they imply that the signals are intended to be received by someone or something (not necessarily us) beyond the immediate space about the transmitting planet.
SETI@Home is certainly not ignoring non-barycentric signals, they are only prioritizing the (literally) billions of potential 'hits' they have accumulated. I'm quite sure that if we started seeing large gaussians every time Arecibo swung past Proxima Centauri, nobody would ignore them even if the peaks Dopplered a bit from planetary orbital motion.
On the flip side, no--we are not broadcasting any barycentric signals right now. An alien SETI@Centauri project might assign us a slightly lower priority because we're not making a deliberate effort to be noticed. Nevertheless, continuous radio and television signals across multiple frequencies would probably make us quite an interesting target to any race with good enough detectors and large enough dishes.
Me? I'll spend my spare CPU cycles trying to find a drug combination to cure cancer.
Very noble of you. Among other things, I have spent my own time, not my computer's, working on cures for cancer. (Right now I'm back at school.) I could have been earning much better money pushing paper--actually, I took a 25% pay cut to do cancer research.
You know what? I was running SETI@Home on my computer at the time. And I don't feel guilty about it. Maybe there was a better use for those cycles, but I think of it as a sort of hobby for my computer. People who spend their spare time watching football, or playing with electric trains, or painting--forget what their computers are doing, shouldn't they be working on 'more relevant' problems?
Breast cancer killed my best friend's mother this summer. I would love to see a cure for cancer, as well as for any number of other diseases--Alzheimer's runs in my family, and my uncle has diabetes. But if fear of death is to set all of our priorities, leaving no room for a sense of wonder and exploration--what's the point of living?
If you really want to help people in a tangible way, please--go out and give blood. Not just after a terrorist attack, but every two months. Or volunteer at a food bank. Not just at Thanksgiving, or Christmas, but year round. Write a cheque to a charitable organization. If you can't afford that, write a letter to your government representative--tell them what their funding priorities should be.
How exactly do you test the validity of a formula like this?
I assume you would test it by examining a large number of star systems for signs of life. Since we have only one firm data point (our Solar System) there has to be a lot of handwaving. The formula is designed to weight more heavily stars similar to our own (though there seems to be a copy error in the exponential factor--a negation has been lost and it actually weights for stars that are least like the sun.)
The first factor penalizes young, short-lived, blue stars.
The parallax term seems to bias the score in terms of more distant stars--again, this might be a typo.
The formula is just a tool to aid SETI@Home astronomers decide which stars are more likely to bear life, since they can't investigate all of them. It's a guess, nothing more.
The easiest way to separate the gases is to work inside a U-shaped tube with one electrode in each arm. You get H2 in one arm and O2 in the other. If you can't remember which arm is which, the hydrogen side will deliver twice the volume of gas.
I've seen the effects of a low pressure cylinder failing. To celebrate Hallowe'en, I got together with a group of friends, some pumpkins, and a dewar of liquid nitrogen. (Obviously, we're chemists...)
Fill a half-litre plastic pop bottle to about the halfway point with LN2. Place inside a pumpkin. Run.
When enough nitrogen boils off the bottle will rupture, detonating the pumpkin. It's quite a sight. We had pumpkin shards up to about 200 ft away. Warning to the bold: I have left at least one important detail out of my instructions. Only qualified individuals should attempt such a stunt. I assume no responsibility for their actions.
That said, you could always put the hydrogen cylinder outside and just run a hose to the UPS. Really, you could put the whole UPS outside, and just run a cable to the server room. Catastrophic failures of gas cylinders are extremely rare, unless the cylinders are abused. I've mentioned on a different thread: treat the tank like a server and it will be fine. (No open flames, no intense heat, no massive blunt trauma.)
Do I really want to be carrying around pressurized containers of hydrogen near me?
Do you ever barbecue? Propane or charcoal? Propane is a pressurized container of explosive gas, but nobody gets too bent out of shape having it around. It's actually arguably more dangerous than hydrogen, since it's denser than air. A small propane leak will tend to pool in the low spots in a building until it builds to a dangerous level. Hydrogen tends to rise, and the small size of its molecules permits it to diffuse much faster, too.
Many homes have natural gas lines, running to the furnace, the water heater, the kitchen stove. Again, few people are concerned. I do lab work, and I've usually got a couple of cylinders of methane next to my desk. I don't panic at the thought of going to work. Well, not for that reason, anyway.
Hydrogen gas cylinders are fairly harmless, as long as you have a little bit of respect for them. Don't do anything to a cylinder that you wouldn't want done to your server, and you should be fine. (ie, don't tie it to the back of your car and drag it down the street. Don't knock it over too often. Don't expose it to intense heat or open flame.)
Also, there's nothing that prevents you from putting the tank outside and running a hose through the wall to wherever you need gas.
It's not hard to prove at all. All you need are a pile of space rocks and comets with life on them that isn't descended from life on Earth.
Right! All we need to do is find fossils that are four billion years old, containing intact genetic material. Oh yes--they have to be from other worlds. No problem there.
Panspermia doesn't bother me as a theory; it is definintely a plausible explanation, particularly for the transfer of life from one world to another within the Solar System. But it is by no means the only reasonable solution, as you would imply. And proving it is much more difficult, practically speaking, than you think.
Okay, fair enough. But we're still not in any position to speak of proof of the existence of life on Mars. Personally, I'd be thrilled if there was. But so far we've got one ambiguous blob in one meteorite. I'm waiting for a mission--manned or otherwise--to return some samples from the planet.
For now, we can point at Mars (or Europa, or Io, for that matter) all we want--we still can't say if Earth's life originated in any of those places. We can't even say that life existed in any of those places.
Hm. Freudian slip, I'd say. Presumably we're talking about hydrophilic compounds--ones that 'like' to intermingle with water, and not...um, something else in water...
The real question is, was life seeded from an object from space carrying single celled life? Has this been disproven/proven yet?
This one is really, really hard to prove unless you can find the original life-bearing world from which the first cell originated.
Even if you manage that, you're still stuck back with the question of how life started on that world instead of this one. You might as well work on mechanisms for the origin of life on earth, since it remains the only world on which we are sure life has ever existed.
With Ender's Game, the issue is the number of capable child actors needed for the film.
"I see dead people...uh, I mean, buggers. I see buggers. Damn. Cut!"
Seriously, the other problem with Ender's Game is that the children need to age several years during the course of the story. Adults are easy to age--add some grey hair, a few wrinkles--or stop hiding the wrinkles that they have. Making kids taller and older is much harder, though it can be done--LOTR has the same problem but backwards in dealing with Hobbits...
The other difficulty arises because a lot of the important stuff in the movie happens in zero gee. It's really expensive and quite difficult to have armies facing off in zero g without looking really stupid. OTOH, a good rendition of the Battle Room would by itself be worth the price of admission to such a movie.
The first three books (in meatspace chronological order) Foundation, Foundation and Empire, and Second Foundation were originally published as serials in science fiction magazines. Foundation consists of four short stories; the other two books contain two longer stories each. In 1966, this original Foundation Trilogy edged out LOTR to win the Hugo for Best Novel Series. Deserved or not, this honour has never been awarded to another series before or since.
Later books, including Foundation's Edge, Foundation and Earth, and the two prequels Prelude to Foundation and Forward the Foundation were published as complete novels, with a single story in each.
Slashdot Mirror
You're using the most popular--but also narrowest--definition of chemo. Pull out your Merriam-Webster (online at www.m-w.com) and the first definition is a literal interpretation of the term:
Brachytherapy is the implantation of radioactive sources into a tumour to kill them.
Brachytherapy is a blanket term is radiotherapy that covers a range of techniques to place radioactive sources in close proximity to a target volume within the body. It may include the use of sealed seeds (iodine-131 sealed in a casing is often used for prostate cancer) than can be permanently implanted. It also includes high dose rate therapies where wires within catheters or needles tipped with potent radioactive sources (ie iridium-192), are inserted into the body for a few minutes at a time, again to precisely deliver radiation to a controlled volume. The other broad branch of radiotherapy is teletherapy--external beam radiotherapy--which obviously doesn't apply in this case.
The short answer is, yes!
Depending on the size of the sample, you can look at its spectrum of gamma radiation. Different radioisotopes emit gammas at different frequencies when they decay, providing a distinctive fingerprint.
High resolution mass spectrometry will also do it for you. I know a chemist who has tricks for detecting femtograms (1E-15) of an element (though his mass resolution isn't very good, you could see a very tiny amount of a transuranic element like plutonium.)
Really, all you need is to be able to quickly identify areas that are worth further investigation. If you find something that seems suspicious--even if it isn't conclusive--that tells you where to bring in the analytical big guns. Actually, that usually means a lot more cotton swabs. ;)
If you read the linked New Scientist article in the post, or even the original JAMA letter, it states as much.
A letter like that is pretty easy to fake, and I imagine that most police officers don't have the medical physics training to assess that sort of document's veracity on the spot. The recommended letter should include (among other things) "...the physician's 24-hour telephone numbers to allow police to verify the content of the letters."
Really, if you're going to go to the trouble of stopping people who set off radiation alarms, it does make sense to check their stories before you send them on their way. Whether the detectors are at all worthwhile is still a matter worthy of debate.
Actually, the whole point of the iodine treatment is to destroy part or all of an overactive thyroid. Afterwards, most of these people live quite happy, quite normal lives. Some of them need to take hormones to top up what the thyroid is no longer providing, but usually their lives are not significantly shortened.
Besides, if you're prepared to do surgery to implant radioisotopes for smuggling, you'd be better off putting it in your chest cavity somewhere. Most people just don't have a lot of free space in their necks.
Soon as the news hits that the New York subway system is contaminated with radioactive material, there will be panic, regardless of amount. And it wouldn't take a very big container of material to do it, either.
Tremendous amounts of fear; no bomb required. Remember when there was anthrax in the mail? You can scare a lot of people without any explosions.
In this case, it is.
Graves disease is a form of hyperthyroidism, in which the thyroid secretes excessive amounts of certain hormones. The treatment of Graves disease involves removal of part or all of the thyroid, chemical supression of hormone production, or destruction of the thyroid using radiation.
In the latter treatment, doctors take advantage of the fact that iodine is concentrated by the body in the thyroid gland. After dosing a patient with radioactive iodine-131 (in this case, 20 millicuries--a nontrivial amount) the iodine will accumulate rapidly in the thyroid. While it decays, it kills off most or all thyroid tissue without doing serious damage to the rest of the body. With a half-life of about eight days, the stuff remains detectable for quite a while.
So--what we've done is use the chemical properties of a material (I-131) to deliver radiation therapy. Presto! Chemotherapy that is also radiotherapy. Actually, I'd probably lean towards describing it as brachytherapy, just to make everyone happy.
But we're still screwed. Almost all the links on Slashdot--and more importantly, on porn sites--use names, not IPs. Damn.
I realize that the parent poster is probably just playing devil's advocate--most likely with a healthy dose of sarcasm.
The important point is that the sender pays for the snail mail that I receive--when it comes to my door, I don't have to cough up for my letters, whether I want them or not. Email is a collect call, and one that you can't refuse to accept. Physical and electronic junk mail both waste my time, but spam costs me money.
You're right; I did forget Friday. That said, at the end of the book, she still settles down on a colony world with her new life partner--a doctor--to start making babies. Go figure. I guess I'm impressed that Heinlein stretched himself a little bit. ;)
Alas, his books are not the deep, meaningful volumes they are usually represented to be. (Stranger in a Strange Land has its moments.) They're delightful stories and fun to read--I admit I often can't put them down. But they nearly all follow the same basic premise of attractive young woman (women, often) and dirty old man have exciting adventures, say witty things, are unbearably clever, outsmart the bad guys, then have sex (usually incestuous).
That said, I can see why the dirty old man sleeping with attractive and brilliant young woman has appeal on Slashdot.
Gee, if I wanted that, I'd dust off my C-64 and play. They built those things solidly...nearly two decades, and I've had to replace the power supply brick. And that's it. Granted, use has tapered off significantly over the last decade, and the joysticks that have suffered from heavy usage need replacement, but still...
There's something to be said for avoiding the hard drive as a point of failure.
If you're from anywhere else, yeah--I saw that one coming. [rueful grin]
This is a pretty reasonable approach, actually. Barycentric signals imply deliberate action. Further, they imply that the signals are intended to be received by someone or something (not necessarily us) beyond the immediate space about the transmitting planet.
SETI@Home is certainly not ignoring non-barycentric signals, they are only prioritizing the (literally) billions of potential 'hits' they have accumulated. I'm quite sure that if we started seeing large gaussians every time Arecibo swung past Proxima Centauri, nobody would ignore them even if the peaks Dopplered a bit from planetary orbital motion.
On the flip side, no--we are not broadcasting any barycentric signals right now. An alien SETI@Centauri project might assign us a slightly lower priority because we're not making a deliberate effort to be noticed. Nevertheless, continuous radio and television signals across multiple frequencies would probably make us quite an interesting target to any race with good enough detectors and large enough dishes.
Very noble of you. Among other things, I have spent my own time, not my computer's, working on cures for cancer. (Right now I'm back at school.) I could have been earning much better money pushing paper--actually, I took a 25% pay cut to do cancer research.
You know what? I was running SETI@Home on my computer at the time. And I don't feel guilty about it. Maybe there was a better use for those cycles, but I think of it as a sort of hobby for my computer. People who spend their spare time watching football, or playing with electric trains, or painting--forget what their computers are doing, shouldn't they be working on 'more relevant' problems?
Breast cancer killed my best friend's mother this summer. I would love to see a cure for cancer, as well as for any number of other diseases--Alzheimer's runs in my family, and my uncle has diabetes. But if fear of death is to set all of our priorities, leaving no room for a sense of wonder and exploration--what's the point of living?
If you really want to help people in a tangible way, please--go out and give blood. Not just after a terrorist attack, but every two months. Or volunteer at a food bank. Not just at Thanksgiving, or Christmas, but year round. Write a cheque to a charitable organization. If you can't afford that, write a letter to your government representative--tell them what their funding priorities should be.
I assume you would test it by examining a large number of star systems for signs of life. Since we have only one firm data point (our Solar System) there has to be a lot of handwaving. The formula is designed to weight more heavily stars similar to our own (though there seems to be a copy error in the exponential factor--a negation has been lost and it actually weights for stars that are least like the sun.)
The first factor penalizes young, short-lived, blue stars.
The parallax term seems to bias the score in terms of more distant stars--again, this might be a typo.
The formula is just a tool to aid SETI@Home astronomers decide which stars are more likely to bear life, since they can't investigate all of them. It's a guess, nothing more.
The easiest way to separate the gases is to work inside a U-shaped tube with one electrode in each arm. You get H2 in one arm and O2 in the other. If you can't remember which arm is which, the hydrogen side will deliver twice the volume of gas.
Fill a half-litre plastic pop bottle to about the halfway point with LN2. Place inside a pumpkin. Run.
When enough nitrogen boils off the bottle will rupture, detonating the pumpkin. It's quite a sight. We had pumpkin shards up to about 200 ft away. Warning to the bold: I have left at least one important detail out of my instructions. Only qualified individuals should attempt such a stunt. I assume no responsibility for their actions.
That said, you could always put the hydrogen cylinder outside and just run a hose to the UPS. Really, you could put the whole UPS outside, and just run a cable to the server room. Catastrophic failures of gas cylinders are extremely rare, unless the cylinders are abused. I've mentioned on a different thread: treat the tank like a server and it will be fine. (No open flames, no intense heat, no massive blunt trauma.)
Do you ever barbecue? Propane or charcoal? Propane is a pressurized container of explosive gas, but nobody gets too bent out of shape having it around. It's actually arguably more dangerous than hydrogen, since it's denser than air. A small propane leak will tend to pool in the low spots in a building until it builds to a dangerous level. Hydrogen tends to rise, and the small size of its molecules permits it to diffuse much faster, too.
Many homes have natural gas lines, running to the furnace, the water heater, the kitchen stove. Again, few people are concerned. I do lab work, and I've usually got a couple of cylinders of methane next to my desk. I don't panic at the thought of going to work. Well, not for that reason, anyway.
Hydrogen gas cylinders are fairly harmless, as long as you have a little bit of respect for them. Don't do anything to a cylinder that you wouldn't want done to your server, and you should be fine. (ie, don't tie it to the back of your car and drag it down the street. Don't knock it over too often. Don't expose it to intense heat or open flame.)
Also, there's nothing that prevents you from putting the tank outside and running a hose through the wall to wherever you need gas.
Right! All we need to do is find fossils that are four billion years old, containing intact genetic material. Oh yes--they have to be from other worlds. No problem there.
Panspermia doesn't bother me as a theory; it is definintely a plausible explanation, particularly for the transfer of life from one world to another within the Solar System. But it is by no means the only reasonable solution, as you would imply. And proving it is much more difficult, practically speaking, than you think.
For now, we can point at Mars (or Europa, or Io, for that matter) all we want--we still can't say if Earth's life originated in any of those places. We can't even say that life existed in any of those places.
No worries. I've had a few boners in my posts, too.
Hm. Freudian slip, I'd say. Presumably we're talking about hydrophilic compounds--ones that 'like' to intermingle with water, and not...um, something else in water...
This one is really, really hard to prove unless you can find the original life-bearing world from which the first cell originated.
Even if you manage that, you're still stuck back with the question of how life started on that world instead of this one. You might as well work on mechanisms for the origin of life on earth, since it remains the only world on which we are sure life has ever existed.
"I see dead people...uh, I mean, buggers. I see buggers. Damn. Cut!"
Seriously, the other problem with Ender's Game is that the children need to age several years during the course of the story. Adults are easy to age--add some grey hair, a few wrinkles--or stop hiding the wrinkles that they have. Making kids taller and older is much harder, though it can be done--LOTR has the same problem but backwards in dealing with Hobbits...
The other difficulty arises because a lot of the important stuff in the movie happens in zero gee. It's really expensive and quite difficult to have armies facing off in zero g without looking really stupid. OTOH, a good rendition of the Battle Room would by itself be worth the price of admission to such a movie.
Later books, including Foundation's Edge, Foundation and Earth, and the two prequels Prelude to Foundation and Forward the Foundation were published as complete novels, with a single story in each.