Mike PSS

I think mungbean has umbrage with this statement. And so do I.
Dave,
If you quote Smyth and parrot his numbers then you accept his measurement accuracy. Simple.
Dave,
Petrie gives numbers that are plus/minus inches, not hundredths of an inch like Smyth.

And if the accuracy of PI is being discussed using Petrie's numbers (plus/minus 1%) instead of Smyth (plus/minus 0.01%) then you get a range of "magically occurring PI in the GP" of 3.11 to 3.17. And ALL the non-mystical ways that I showed you in the references fall into this range.

mung bean

I think we need to be a little more rigorous on the maths here (but then I'm a pedantic bastard).
Smyth's measurement for the base of the GP is 9131.05 inches.
0.01 inches is actually 0.0001% of this.

You're right about teh umbrage though.

Edit: Anyway, regardless of the percentage the claimed accuracy of 0.01 inches is just plain dishonest and stupid.
Smyth must have known damned well that his measurements could not really be that accurate.

Amaleq13

I believe Jet Black was referring to this thread:

Cornell Geneticist: Degenerating Genomes Disprove Evolution

mung bean

Since Shirley's question was originally about sediment in Egypt, and since this thread seems to be covering a range of Egypt-related topics, it occurred to me that the Nile delta may be relevant. This led me, quite naturally, to the Messinian salinity episode in relation to the Genesis timeline, which I have decided merits its own thread.

Located here: http://www.iidb.org/vbb/showthread.php?t=212476

BWE

The problem of carrying capacity is beyond me. I asked a colleague who gets the underlying math in the software much better than me. Rather than try to explain I'll just post her reply to an email I sent her. I'm hoping someone here wants to figure this out. Normally, carrying capacity, although a function doesn't owe any increase to intention on the part of an organism. In this case, we have to start with a reserve but a carrying capacity of 0. I use software I don't write it.


Anyone?

Calilasseia

Now that I've read the page, it makes basic sense. It's an iterative process based upon something called the Verhulst Equation, albeit a discrete form instead of a continuous form. The continuous form of the Verhulst Equation is a differential equation:

dP/dt = rP(1-P/K)

where P is the population, r is the growth rate, and K is the carrying capacity. What you've been presented with in that web page is the discrete version of the Verhulst Equation - in fact, a more complex situation involving two simultaneous differential equations that are coupled because of, say, a predator-prey relationship, and which have been further transformed into a discrete iterative process.

The fundamental family of curves generated by the Verhulst Equation is the sigmoid curve, which has your population growing from a low starting point, then climbing as the numbers build up, until braking factors begin to take hold and the population levels off. The resulting curve is S-shaped, hence the term 'sigmoid'.

The BIG problem with even the simplest form of the Verhulst Equation is that it forms the basis of a chaotic dynamic system. Solutions can be nice and smooth, alternatively they can oscillate like mad. Start introducing population dependent functions that govern reproduction, and it becomes even nastier in this respect.

In the above paragraph, 'chaotic' has a precise mathematical definition. It involves sensitivity to initial conditions, which means that a small change in the starting values results in a large change in behaviour further down the line. Also, the behaviour exhibits bifurcations, where a small change in the initial conditions can suddenly snap the behaviour from a smooth sigmoid curve to an oscillating curve that swings between two stable values, followed by another bifurcation where the curve oscillates between four stable values, and so on. These bifurcations pile up rapidly once you enter the bifurcation régime, until the system oscillates between thousands of values and there is no obvious stability.

Even simple equations can exhibit chaotic dynamic behaviour of this sort, but differential equations can be notorious for it. The Verhulst Equation is a particularly interesting example, and if you have two simultaneous Verhulst Equations that are feeding into each other, the entry into the bifurcation régime can be unpredictable.

Mike PSS

YEAHHHH!!!

What Cali said!!!!!

{flexes puny math muscles in faux show of strength}

MATH IS DA BOMB!!!

That's right. Bring it on. We're doin math here..... that's right.

Uuuunnnnnnnngggghhhhh!!! {muscle flex of course}

Mike PSS

I have this thesaurus thingy in my head and I need to bring up those words every once in a while.

Glad to know I can call you a bastard. BTW, you can call me a jerk.

The whole accuracy thing sticks out like a sore thumb. It's a basic tenent of engineer school to look at your significant figures and measurement accuracy. Math is fine, but the results have to fit into the reality your dealing with. In Smyth's time I doubt they could get closer than a tenth of an inch in measurement of the GP. And all the other reported measurements from Petrie, or even Wiki, give errors in whole inches, not hundredths of an inch.

But since Dave has forgotten this detail from his engineering training oh so many years ago I guess we'll have to walk him through the whole "sig figs/error bars/accuracy/precision" points that all the rest of us learned in freshman year.

Sad really. Dave will probably argue against sig figs for some reason because it would go against his biblical innerency or something.

BWE

Population dynamics software uses differential equations for every factor (I think). When you tune a model (adjust the inputs until the output matches real data), very slight changes to inputs typically create wobbles in the line somewhere. And, like I said before, If they were fish, my software gives them a really really slim chance of survival at all. Best case scenario to arrive at the needed population was around 10% unchanged growth rate. The problem with figuring Noah out is that they start with carrying capacity zero. The carrying capacity is it's own population graph tied to the humans' and, appropriately enough, to the beasts of burden and consumption. The math gets so hairy so fast that I give up. Because you have multiple iterative processes as CaliLassia said, you are almost guaranteed to need a separate equation to measure the degree of possibility at every independent equation's solution. Fluctuation can only go up as fast as dave's Malthusian formula set to a maximum possible birth rate and number of offspring. The thing to remember is that actual fluctuations are not happening as percent, they are real numbers. Often they are a function of size (like it's more likely to lose a million out of a population of a billion than two million) but they are real numbers and a fluctuation of -100 with a population of 100 is nearly inevitable.

Dave's idea is so far off the charts that I am left shaking my head. Can excel even do that much math?

mung bean

The funny thing is that in this particular case the sig figs actually have no direct bearing on his desire for a literally true Bible.
Therefore one might expect him to be reluctant to quote figures which are obviously dodgy. I could understand him defending them if they were critical to his worldview, but to open himself to ridicule over such a trivial and tangential issue seems rather odd.

Edit: this post refers to Mike's.