RonSewell (C63),
How is this [hCG] measured? If it involves in any way chromatography, ion-selective electrode electrochemistry, chemiluminescence, or any form of analog analytical instrumentation, I can guarantee you from a career in instrumentation that a turndown of 100,000 to one is a fantasy of at *least* two orders of magnitude.
Very good. I went over to the lab at one of the places where I work and asked, and the lab tech did not know the method used (and I can’t tell by looking at the machine), but did state that a preliminary run was made, and then a dilution of up to 1 to 100 was done for samples with very high hCG. Looks like your estimate was spot on. The point is that we do not tell them whether to dilute or not; they figure that out on their own (we wouldn’t necessarily know in advance anyway).
It is ridiculous to have labs actually doing the measurements stating their own results are only valid to their specified limit, and have somebody tell them from outside, “no, you do not understand. Your turndown goes to zero!”
I agree with you, which is why I have never said that the turndown goes to zero. I disagree with some of my colleagues’ previous statements, and hope that they have, or will, come around to recognizing that laboratory contamination is not usually zero (I don’t like to say “never”, but in this case we come pretty close).
(C62)
Contamination *is* a complete explanation, and in fact an expected one.
How could you test that statement?
jammycakes (C64),
PaulGiem:Yes, that would work if all one said was that it was Cretaceous. But what if they were told that the formation was late Maastrichtian, or even the K-T boundary? That would narrow the time period considerably.
- What evidence do you have that geologists are actually doing this?
- Even if they were doing it, it would still be perfectly legitimate if they were doing so to narrow down the errors from, say, ±5% to ±0.5%
First, the only evidence I have is anecdotal, but the form does ask for it, and I have no evidence that people are sending in samples without filling out the form. I’m no arguing that people always give the geological horizon to the lab before the report; I’m only asking that we run a series of tests where we can know that they are not doing so.
Second, I think it would be more convincing if the lab gave the date before knowing any target, just like the lab does for hCG. So it’s a little more expensive. Then those of us who are interested will pay a little more for it.
I got it from this BBC news report:…
I see no reason to doubt it. Pushing the boundaries of accuracy and precision is an active research topic in every area of science. So while you may not get figures that tight from commercial laboratories, it is only to be expected from university departments working on new cutting-edge techniques.
…
… In any case, what exactly do you mean by a “composite date”?
Thanks. I looked at the report, and it cited an article in Science ( https://science.sciencemag.org/content/339/6120/684.abstract ). In the article itself, I found this:
All of our data combined yield a weighted mean age of 66.043 ± 0.011/0.043 Ma.
That’s what I meant by a composite date. (Not that there’s anything wrong with that.)
22,000°C, Paul. Twenty. Two. Thousand. Degrees. Centigrade. And remember, that was the RATE team’s own admission.
I already told you that IMO that horse was as close to dead as it can be given the nature of science. Please. Stop. Beating.
You don’t seem to understand the point I was making.And you don’t seem to understand the point that I was making.
I hope we don’t find ourselves with complete mutual misunderstanding.
I agree that it makes a difference whether the dates disagree with each other (and in the case of recent lava, with the known real age) 2%, 10%, 50% 90%, or 98% of the time. So other than who is going to pay for it, what’s the harm in doing a blinded test with all results reported? In the meantime, we can still act politely to each other.