John Cuthber

Orlistat works by blocking the enzyme in the gut that digests the fat. Broadly, if you were to block 25% of the enzyme then only 75% as much fat would be digested (and therefore absorbed).

Since, for any given person, the amount of enzyme is pretty much fixed the amount of drug needed to block it is also fixed.

The problem with orlistat (and others like it) is that the undigested fats can cause problems. They are generally liquid at body temperature and the lower end of the gut is not comfortable with, or good at, holding back liquids.

"imagine theres a horizontal planeA bove which the effects of gravity are not felt."

there isn't one.

They use hydrogen as a neutron moderator because it has the same mass as the neutron. The deutierum that alos gets used (because of a poor capture crosssection) while it is only wtice the mass of the neutron does a noticably poorer job. Aluminium is a lot heavier and will barely reduce the momentum of the neutron at all.

Al simply isn't a light nucleus so it doesn't work very well, so yes, I read that bit of the article and I know what it means.

Since it takes somthing like a foot of water to thermalise neutrons, surely you can see that a few mm of something that's a poor moderator is a non-starter.

The lead is, of course, heavier still and therfore even less use.

I'd still like to know why you think they can nuclear fuel elements in Al if you think it will block the neutrons.

On the subject of the OP; where's the chemistry?

A homogeneous reactor is possible; they happen from time to time by accident but you need a lot of enriched highly fissionable material to do it.

http://www.uic.com.au/nip52.htm

but if a single Uranium to Barium reaction has the power to move a grain of sand, then thousands of these at the same time Should make heat!

Each fission event releases about 200MEV i.e. about 3.2*10^-11J

A thousand of them a second would generate thirty two whole nanowatts.

What do you plan to do with that?

A reactor will generate heat, if you can get one to work. Many countries don't have the resources to do that, so I don't see you doing it any time soon. Possibly just as well if you plan to sheild it with Aluminium.

"I should have used the polticially correct terms; chemistry creates conditions that could be mistaken for phenomena in physics. I didn't mean to intrude or be rude and crude. "

This is nothing to do with terminology; it's to do with you not understanding what "hot" means.

"Say we have a core of solid deuterium/tritium"

No, don't say that, because the early universe was very hot, far too hot for these gases (one of which barely exists) to solidify.

"I'll possibly get shot for this but.....

Am I the only one who finds it amusingly ironic that the main claim to fame of the proclaimed leader of the "If I can't it or measure it, it doesn't exist" brigade is a philosophical/psychological concept that cannot be seen or measured?"

OK so Dawkin's claim to fame is biology and you don't think that's measurable?

I thought that people were doing mathematical modeling of repearted games and such looking at evolutionarily stable strategies and such that depend on the idea. Not a direct measure but a measure nopne the less.

OK what's his claim to fame?

A plane crash might not disperse all the fuel but it does a good enough job that the videos of plane crashes show fireballs.

I think this is sufficient to bring the previous unsuported statement "I never knew airplanes had fuel atomizers and igniters installed... " into question. I think that's all bombus was pointing out.

"There is H2 as a gas, liquid and solid."

Didn't you understand the bit about it being too hot?

"But in modern times, chemical affects can explain things like dark matter."

Plain wrong.

"Here is Florida during the summer you can see little dark gray clouds floating near bright white clouds. These are dark matter clouds."

Plain wrong again.

"What they are doing is absorbing the light with very little emission back."

Wrong, yet again.

Please go and learn some physics and chemistry before posting stuff like this.

"Any suggestions for getting the last traces out?"

Toothpaste on a bit of rag.

" have to ask why you think a fire alarm Am241 slug would do the job?????"

I didn't in fact I thought I made it preetty cleare that it wouldn't do the job. On the other hand I think it's about as potent a source as most people have access to.

If you can get hold of a source a million times better then you only need to wait a million years or so.

Heavy water is actually a less effective moderator than ordinary water, It gets used because its capture cross section is smaller. You would need more of it so the problem gets even worse because more water means more BaSO4 would dissolve and so you would need more to precipitate it.

Essentially you are trying to build a nuclear rector. I don't think most governments are up to that never mind individuals.

Also, re neutron screening.

http://hps.org/publicinformation/ate/q1094.html

4th paragraph of the answer.

I don't see why you think Al has some magic property of blocking neutrons. Al alloys are used as fuel cans in reactors. How well would they work if the neutrons never got anywhere?

It has a capture cross section of about a quarter of a barn. Steel would do a better job.

"there are only 3 metals that are naturally ferromagnetic"

these 3 are Fe, Ni, Co, Gd and (I'm told) Pu.

"In this span of time, chemical affects should be the dominant affect."

Why?

It's far to hot for any bonds to form and, until the hydrogen has colapsed into stars waited till they burned down a bit and got fused into the heavier elements, there's only hydrogen.

Only one element doesn't give you a lot of scope for chemistry.

Essentially no chemistry takes place until planets start to form.

I don't think "a few mil of Alu and then Lead plate " will get you anywhere at all as a neturon shield.

I've only got tables of thermal neutron capture cross sections but I don't think that will matter much. I wouldn't want to be hiding behind Al or Pb from a neutron source. The capture probabilities are rather small. A thick layer of water to slow them down then a layer of borax to actually capture them then a layer of more shielding to block the energy released by the capture.

A microgram of barium is about 1/130 µmol so about 5 *10^15 atoms.

Lets say you get a smoke detector as the neutron source. Something like 1µCi or about 37000 alphas a second. With a really good Am/Be source about 30 alphas in a million will produce a neutron.

So you have about 1 neutron a second.

OK all you need is to set it up and wait for something like 10^15 seconds to get your microgram of Ba (the Ba isn't the only possible product but I'm offsetting that against the neutron multiplication by fission; this is a crass approximation).

See you in 31 million years.

Actually, it gets worse than that; BaSO4 isn't very soluble but it does dissolve a bit. My trusty cop of the CRC book gives the solubility as 222µg/ 100 mls.

To be sure of getting the neutrons thermalised you need to send them through a foot or so of water so I can't see you setting this up with less than a liter or so of water (actually, since you would need the source surrounded by water you would need something like a 2 foot dianmeter spherical flask of solution. That's tens of litres.

Well, if 222µg of BaSO4 dissolve in 100 ml than that's 22200 µg disolve in 10 litres.

See you in six hundred billion years.

Shaddowacct I'm puzzled by some of thepoints you raise.

"Religion is about hope, about a better future."

That's not a definition I had heard before. I though it was about faith; the antithesis of evidence. The "better future" bit generally kicks in after you are dead- that's remarkably useful in terms of finding dissatisfied customers comming back to complain

"Keep your eyes open, do you really think all those old religions have nothing to say?"

Not that can't be said more logically by other things.

"These old books really have very little useful information?? "

OK, what can I really learn from the bible that's not in, for example, Shakespeare?

OK the old languages might be an interesting study in linguistics but that's it; nothing deeper.

"Throw away your roots and history... you also throw away your hope and future."

I don't plan to throw away the history books. They do tell of mankind's past.

I don't have any problem with throwing out a book that tells me that the world was made so recently that I can disprove it by counting tree rings. Strictly, I wouldn't throw it out, I'd just recatalogue it as mythology.

I don't see what this secular God is that you talk about. I'm on about looking at things and beleiving the evidence. Not an act of worship. How can you possibly think that actually looking at the evidence will be the end of science?

Speaking of evidence.

"AL: live and let live CAN work and indeed Has, look at the Animal kingdom (of which we are a part of I might add) they only attack when either Threatened or Hungry."

Domestic cats are well fed but they still torture birds and small animals to death.

That's hardly a policy of live and let live, or are you saying that cats live in fear of small birds?

Anyway, as I said I don't mind living and letting live- provided that it doesn't foul things up for me.

Should I go about my business and let terrorists go about theirs?

I note that Paranoia and I must have written much the same thing at the same time.

Sory Shadowacct, but I don't know much about Kim Il sung's regimen. Given the context in which you mentioned it I presume that when the evidence showed that it had problems it was scrapped and replaced. Either that or you seem to have missed my point.

Have you read 1984? It is about a state that exists by telling lies- the very antithesis of one based on evaluating the whole of the evidence. It's also one of the most desperately bleak books I have read. If anything it's a point in favour of my belief that an evidence based government would be good by showing what an evidence free world would be like.

I realise that the people in power would probablty try to corrupt the government to their onw personal ends but I can't help that would be more difficult if everyone were in the habit of thinking.

Rationallity doesn't preclude art by the way. The fact that people like old buildings is a reason to keep them. The fact that we could build, for example, more energy efficient ones is beside the point. I don't need to explain why I think that an old building is beautiful, if enough people agree with me then that's the end of the debate- the building stays.

I'm not sure about this statement from 1Veedo "I think ParanoiA is right when he says Dawkins is careful when criticizing religion (post 51) and the proof of this is the fact that Dawkins doesn't even like the title of his own TV show."

This is the man who wrote "The God delusion" (his title for it) and, in it, says that we should not be defferential to religion. He says in effect that we should think how we would react to someone saying "I live my life according to the laws of the invisible fairies at the bottom of my garden" and realise that's exactly how we should treat someone who says "I live my life according to the laws of one super-fairy who not only inhabits the bottom of my garden but everywhere else as well, but that's OK becase He made everything." Making the case that religion resembles insanity isn't being that careful about it.

I think Paranoia is dead right saying "You may be right. It seems more likely, to me anyway, that he's saying it's the combined effect of all of the various unsubstantiated beliefs in the supernatural and the declining interest in actual science that is the root of all evil. " and it puzzles me that anyone of a scientific nature doesn't agree.

Personally I'm an atheist because I prefer to believe the evidence of my own eyes rather than the fairy tales told to me by a man in a dress.

I also think that evangelising the message "don't ask me to think for you" is rather less bad than the other evangelisms I have seen. (And I'm not sure it really counts as arrogant)

I wouldn't mind the idea of people believing ridiculous things if it didn't impact on me. On the other hand, as I have mentioned elsewhere on this site, I think that these daft beliefs are the pathway to an irrational outlook on life and that bothers me.

Accepting things as being true becomes a habit. Then, when you are asked to accept that, for example, the Jews were entirely responsible for the economic problems of Germany in the 30s, you are more likely to accept it. You just won't have had the practice at thinking for yourself.

The same lack of proper respect for evidence also leads to things like the MMR farce. That "story" should have died out before it got anywhere but (thanks partly to the media) it got credibility that it never deserved.

Again I think that if people were taught to think for themselves rather than to have "faith" this mistake wouldn't have happened.

They melt.

It seems that if you make sure there's a fire to light the gas you get quite a hazardous effect.

http://www.youtube.com/watch?v=QFPedGsqtrs

Dear me! did I just cite youtube as a reference?

People don't, as a rule, kill people.

In order to get your soldiers to kill the oppositions soldiers its easiest to make believe that they are not killing other humans at all. You need to find some way to label the opposition so that they are, for example, vermin. Then it's not killing people; it's just pest control.

A good way to make the "other side" look like vermin is to label them as dirty unbelievers (I accept that labeleing them as dirty believers of the "wrong" faith worked very well for Hitler but the difference between "no faith" and "not our faith" is easilly overlooked).

Religion is clearly one way to do this- race is another. There are probably others too.

The other thing you need to do in order to get people to kill other people (in addition to dehumanising them) is to give some sort of moral justification for the deaths.

"they invaded our land" or even "they invaded our friend's land"

works quite well but who can argue with "God says it's right"?

Well I can because I don't believe in any God. On the other hand, those brought up to believe, for example that wafers of bread and a sip of wine turn into flesh and blood on the way down the throat are used to accepting absurd notions.

Start them while they are young believing in Santa Claus and keep them mystified by misrepresenting the truths that science has produced and they will be much easier to manipulate from the point of view of those in power.

Even the mild mannered church of England still encourages a lack of thought on matters of "faith". As such it is just as dangerous as any fanatical band of nutters.

Once you accept that it's OK to tell lies then you have crossed the line. Unless you accept Genesis as historical fact then you have to accept that preaching it as anything but an ancient myth or a metaphor is dishonest.

Race is another contentious point. My observation is that people are poeople and there's not a lot of difference between the so called races. That makes racist belief irrational (at least in my experience). It's easy to raise a rabble with a cry along the lines of you fear them because they are different so burn them to death. (It's funny, but they never seem to phrase it like that)

To try the same with "They are damn near identical to you- burn them to death" won't work so well.

Only if you can get people to act irrationally can you get a race riot started. (and like any riot, once it's started it's very hard to stop). Religion and the anti- science movement are a part of promoting that irrationallity.

Wouldn't we be better off without them?

As for "If the UK would receive a government, which is totally in line with the point of view of Dawkins, would the UK be a good place to live?

If the UK would receive a government, which is totally in line with the point of view of ANYBODY, would the UK be a good place to live? Hell no. "

There's a world of difference between a dictatorship by Dawkins and a government based on his viewpoint ie that all decisions should be based on the best available evidence.

If someone sets up a country which subscribes to the latter then I am going to apply for nationallity.

Well, I may have missed a few things but here's my thoughts.

Last time I looked NMR used radio waves to do the spectroscopy. I guess they might be into the microwave region by now so that's a tacit spatial resolution of a centimetre or so. With some clever tricks you can get MRI images with resolutions of a milimetre or so.

I thought the half micron that you could get with a laser was hopeless. Half a milimetre is a whole lot worse.

It gets even worse still if you think about the signal to noise ratio. In general terms the higher the energy photons you use, the easier it is to see them against the background noise.

It's relatively easy to see the effect of a single gamma ray photon form a decaying atom

It's possible, but very difficult to observe visible fluorescence emission from a single atom or molecule.

I doubt that anyone has even tried to do this experiment with an infrared transition.

Good luck to anyone trying to do it with microwaves.

I suspect there are also problems with relaxation times.

Or we are back to the problem of trying to line up lots and lots of DNA in perfect register.

Guess why they chose the techniques they do use for DNA sequencing.

Glad to help. (fom the man who has grown Rochellle salt crystals a couple of inches square and 3/8 thick, and has wondered ever since why he bothered)

CPLuke,

when you wrote "not neccessarily tre, if we were a simulation you would expect to see certain artifacts of the simulation develop, for instance there might be certain minimums that would defy eplanation, and also simulation "noise" while the theory could never be falsified it could be confirmed."

how did you know what the laws of the real universe (in which our universe is a simulation) are?

How can you presume to guess about noise in a realm of which you do not, and can not, have any experience.

Just a thought but perhaps the limits we see in this world like the Planck time and so on are just the noise you are talking about much as Martin suggests.

I don't think this is a likely scenario and I don't think that begging them not to switch us off makes any sense but I still don't see how you could test the theory.

In the same way- arguments about it being far to complicated are odd. Too complicated for what? Since we would have no idea what was doing the simulating we shouldn't delude ourselves into thinking we know what it could do.

The idea, like the existence of God, is in principle, untestable.

Anybody just watched part 2 where he rips into alternative medicine?

Anyway, I think Dawkins has a problem with presentation because he takes a stance that society doen't seem to like. He clearly believes (with good evidence- the difference between fundamentalism and science) that homeopathy is total nonsense. When he is talking to someone who believes (probably because they have personal experience) that homeopathy is true he has two choices. He can either come across as an appeaser and say things like "Well it's OK for you to believe that - everyone is entitled..." or he can say what he clearly believes ie "You are plain wrong; that's what the evidence shows".

Since his point of view includes the observations that the UK national Health service (which is permamantly short of funds) has just spent £10 million refurbishing a homeopathic hospital in London and that a lot of wars and suffering are due to religion and (what is more closely related to religion than most people like to say) xenophobia he plainly does not think it's OK for people to think like that because he sees it as a major source of trouble.

it's no shock that he gets annoyed that people refuse to see sense ie they value superstition over their own eyes.

In those circumstances he is likely to come across as arrogant and argumentative.

What else would he do?

I like this explanation "if you go straight up you'll just come straight back down again. if your going to fall and miss the earth(which is what an orbit is) then you need to be going really fast to one side."

Nicely put.

My understanding of ordinary fly-spray is the it hangs in the air for a while and kills bugs anyway. You don't need a "direct hit" to get a kill. (Though it's more satisfying to squirt the bugs.)