Photon counting for the masses

What's with you and strawmen/red herrings?

They make for good discussions, and of course what's a strawman or not is often a matter of opinion.

My point was that... I think it's hard for a "compassionate liberal" to envision a "compassionate conservative" at times (or vice versa), since sometimes what seems "incompassionate" to one is actually a case where the other has a deep-seated belief that certain forms are behavior are fundamentally wrong. This is most vexing to "would-be compassionate people" since the behavior seems inconsistent with *their* belief system.

Indeed, this particular compassionate conservative guy feels that he's being compassionate by offering to provide resources to help gay people "overcome" their sin (as he sees it); he even has a friend who is a councilor specializing in helping gay men and women attempt to change to a "straight" lifestyle.

I don't really agree with much of that at all personally and I struggle with it, but overall the guy is still fixed in my mind as a "compassionate conservative," even though I know some people would apply rather pejorative labels based on some of his beliefs.

People aren't perfect, but the vast majority of them have far more good, lovable attributes that bad, distasteful ones.

---Joel

Yes. Is that a bad thing to do?

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May i suggest also reading "The Abolition of Man" and "The Discarded Image" by the same author (assuming that you have not read them).

?-)

When the subject is charity, you bring up employment. That's Strawman 101.

Look at who gives to charity. Tain't you lefties! Joe BiteMe gave what? $.29 of his $400,000+ income last year?

Which has nothing to do with the subject.

That's a lefty for you, two-faced.

There are 2x more conservatives in the US than liberals.

example,

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A quiet whoosh, a loud whoosh, and a loud roar. With a tiny bit of study i think i can follow the last one.

?-)

I put off asking because I'm sure I won't understand, but I have to ask.

How can RF affect a nucleus?

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It probably can be proven when we get around to making artificial brains.

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Same as light affects the electrons around one -- the QM says so! :-)

NMR (= MRI) is surprisingly simple: when a nucleus has spin, it has a magnetic moment, which can be aligned or opposite to an applied magnetic field. It doesn't take levels inbetween (classically, it transitions very quickly between the unstable opposed state and the aligned stable state), so there is only one transition between energy levels, proportional to the spin (angular momentum) and applied magnetic field. This transition is quite small, but because it's weakly coupled (the nucleus is sitting down there, a teeny ball of dense stuff all by itself), it's not scattered much by thermal effects.

Thermodynamics says, at any given temperature, there will be a population of atoms in the excited and ground states. Since the energy difference is very small, what little thermal energy that interacts with the nuclear moment scatters the states. It can't scatter the energy levels because those are fixed by other physics, but it can change the proportions. Every time a spin flips, it releases a quanta of energy; if it flips up, it's in phase, if it flips down, it's out of phase. If the population is evenly distributed (half aligned, half anti-), they cancel out perfectly and you don't have anything to measure (aside from 1/sqrt(N) granularity: you could still measure a signal from a small sample, but with ~10^23 atoms in a typical sample, your noise floor is in the 3ppt range).

Fortunately, at finite temperatures, the distribution is not *quite* equal. The energy difference is typically in the 100neV range, while room temperature is ~25meV. The resulting population difference is in the ppm range, so you don't have much signal to work with.

Early experiments used a car battery powering an electromagnet*, and a resonant bridge to null most of the apparatus: around the NMR sample is merely an induction coil, tuned to the frequency of interest. To observe the nuclear resonance, frequency was swept slowly (pulse-decay methods came later, particularly with the power of Fourier transforms). For a sufficiently uniform magnetic field of fractional tesla, the proton Larmor frequency is in the 10s of MHz range.

*A window was used to regulate the field strength. Seriously, this is in one of the books or papers by the early authors: they would have the grad student open the laboratory window when it was getting too warm.

Practically, the nuclear resonance simply looks like a very, very weakly coupled, very high Q resonator. The frequency of that resonator depends on the magnetic environment; in a liquid, all molecules look identical, because none spend enough time in a particular relative orientation to matter, and it averages out. As a result, water (which has two hydrogens, bouncing around everywhere) has one narrow, very sharp resonance. However, between atoms on the same molecule, there is some interaction: an organic molecule which contains several hydrogens keeps them in relative proximity, so that they interact, and what used to be a single, small energy level becomes split further. This "chemical shift" is on the order of ppm, which is how NMR plots are labeled. Electron density also causes a shift, allowing identification of the number of hydrogens, what they're bonded to, and what they are in proximity of. Pretty awesome!

The differences between shifted states aren't directly measurable (i.e., you can't measure the 20Hz shift as radiation), because a photon carries spin, and there's nowhere for that spin to go between states with different energy levels but the same spin. So they can only be detected as e.g. 20.000 013 MHz, 20.000 047MHz, etc. Which is still handy, because you can use a very narrow band receiver to do it.

State of the art NMR units are up to 18T or so, which pushes the Larmor frequencies into the UHF band. Because the energy difference is larger, the population difference is also larger, and the signal much stronger; much finer peaks can be resolved, allowing elaborate structural determination.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

I was right. I don't understasnd it. But it's a keeper, which I will review repeatedly.

Thank you.

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Such behaviour is reprehensible, but 304 incidents including swastika daubing and verbal assaults? For a country of 60 million people?

Are these even counted as crimes in the USA?

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John Devereux

Well I don't think we invented it - seems to have been going on for a few thousand years AIUI.

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John Devereux

It is more likely to be *disproven* that way - unless we manage to build a quantum computer with a serious number of qubits (at which point it becomes more likely that our reality is itself a simulation!).

State of the art in 2007 was about half a mouse brain at 10% or realtime speed on insanely powerful hardware - BlueGene.

Although I tend to disagree with his approach Markam has proposed a full human brain simulation that will require exaflop computing power (which should be available in around 2020). For this reason I don't think it should be invested in at this stage - although I think other approaches that ignore the low level detail and simulate neurons as more abstract interconnected objects should be studied.

It would be easier to fit a better model of the neuron into an existing framework of the right overall complexity than to build up a complex structure from cumbersome low level components. Brain simulation is coming and it is just a matter of time now before the computational power and the algorithms are available to do it.

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Regards,
Martin Brown

It's highly probable that the genetic machinery of every cell, every neuron, is a mega-element quantum computer. Evolution demands it. It's likely, at least to me, that each cell has intelligence and probably a sort of consciousness of its own. Well, maybe not much in platelets; they are pretty dumb.

I don't see how a box full of flipflops can ever be more than just that.

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John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

It is entirely reasonable to suppose that the genetic machinery of every cell is dominated by quantum rules. It is still conjecture at present but the fact that DNA encoding is the quantum equivalent of a binary code (if statement single comparison branches 4 ways in the quantum world) and that the number of amino acids coded is about 22 which happens to be near the quantum limit for a 3 step comparison.

It seems fairly probable that the initial DNA/RNA soup became autocatalytic as a result of the quantum superposition rules making certain arbitrary choices as to how the building blocks fit together.

Early stages of casting problems into a form where they can be encoded as DNA and solutions read back have already been done.

Evolution demands no such thing at a cellular level. Only at molecular scales are quantum effects possibly the dominant factor.

It has coded rules about how to behave in every cell, but it takes a large collection of interconnected cells to do anything interesting.

I didn't expect that you would. No imagination at all.

Have a look at the B-Z reaction to see just how complicated an almost trivial redox reaction can become when diffusion limited. The unfortunate discoverer of this was unable to get his work published.

Emergent behaviour is everywhere in complex systems.

--
Regards,
Martin Brown

True. But humans must do it *much* earlier. They simply do not have the ability to apply brute techniques at anywhere near the capacity or speed of computers.

No, I didn't say we don't have the computational power. I was referring only to our being able to apply it to games. AFAIK, no computer or other brain comes close to the human brain in computational power.

Conway's game wasn't a good example, but I agree that simple rules can lead to unbelievably complex results. Witness the Mandelbrot set for example.

But so far, every time we have gotten a machine to reach some goal we thought required intelligence, we've changed our minds about what is intelligence. So, when I was growing up, the gold standard for "intelligence" was the ability to play chess. Now that is no longer considered an activity that *requires* intelligence.

? How do you figure 3^361? I get the 361; where does the 3 come from?

I think you nailed it about go; it can take a long time for a bad move to bear results. Trying to use brute force would require looking way too far into the future, without any reliable way of pruning the tree.

I'm sure that go masters cannot consider all the possible moves. They must have some effective way of pruning the tree, or some other way of thinking about the problem that lets them function efficiently. Is that elusive ability what we mean by "intelligence"? Will we ever build a machine that can take on a go master?

Your comment about intelligence being an emergent behavior is intriguing. I wonder whether some day we'll have truly intelligent machines (by any of our definitions), but still not understand how they do it. At some point it seems that we may need to build the machine and then teach it, rather than trying to program it directly.

It's not just me. As far as I know, most people don't think chess- playing machines exhibit intelligent.

My main reason for doing it is because the way a machine plays chess is unlike how we do it. The machine basically does a brute force approach, with some pruning of the possible branches. A human must do a whole

*lot* of pruning, because his brain can't do the brute force. There is an art to that pruning, something that has defied efforts to characterize it well enough to put it into a program.

But if you want to call that intelligence (what the machine does), it's OK with me. In that case, I would suggest that machines have exhibited "intelligence" for hundreds of years. Your basic thermostat displays a sort of intelligence. Pretty much any sort of a feedback system could be considered intelligence of a sort, as might logic gates and so on.

So your test is already being passed. There are some chat bots that don't sound any crazier than some humans out there. At least, I *think* they're humans... but maybe there are a whole bunch of chat bots out there talking to each other.

OK; I guess I was thinking of each person's moves, not of the three possible states of an intersection on the board.

Thanks for this suggestion, but I'll pass. I just suck at these games of strategy, no matter which ones. Although go does seem like a much more interesting one...

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To use violence is to already be defeated.
		-- Chinese proverb

Evolution demands that every critter used every possible trick to avoid being made extinct by more willing critters. So if quantum computing at the cellular level is possible and beneficial, it happens.

That's an idiotic thing to say, especially given all the follow-ups you do to my imaginings.

Packing more flipflops into a box will never approach the performance of a human nervous system, for lots of reasons. I suspect it can never be conscious either. Too deterministic, too slow. It's funny how a system packed with millisecond logic elements, and meters-per-second transmission lines, can process images better and faster than a room full of GHz CPUs, while dribbling a basketball and chewing gum.

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John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

Hundreds of connections per element instead of half-a-dozen.

But quantum effects might be essential too, and we would know if we made 2 fly brains with 2 different kinds of artificial neurons. One affected by quanta and one not. Simulation would never reveal this.

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Well put.

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over public relations, for nature cannot be fooled."
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