Brief Notes on Neurophysics - PowerPoint PPT Presentation

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Neuron: a specialized cell for signal processing body (soma) with dendrites (receiving signals) and axon (sending signals)

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Brief Notes on Neurophysics

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Brief notes on neurophysics l.jpg

Neuron: a specialized cell for signal processing

body (soma) with dendrites (receiving signals)

and axon (sending signals)

When “triggered”, an “action potential” propagates along the axon. Upon arriving at synapse, it causes the synaptic vesicles to spill neurotransmitter across the synaptic cleft

In human: 1011 neurons, 1014 synapses

cf. 302 neurons, 7000 synapses in a little worm (C. elegans): see PDF

Brief Notes on Neurophysics

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Brain, Consciousness and more

  • Highly connected networks exhibit “emergent complexity”.

  • A “phase transition” is a sudden (in some parameter space) switch to a qualitatively new form

  • Could it be that consciousness (and more) is “just” a phase transition when complexity exceeds some level

  • If so, then “understanding” could be elusive indeed!

  • But could this be accomplished artificially?

  • Similar for “origin of life” …

  • Implications

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Brief Notes on Nanotechnology

  • Origin: Richard Feynman (“There's Plenty of Room at the Bottom” 1959 !)

  • First PhD on molecular nanotechnology: Eric Drexler, from MIT in 1991

  • Principle: like molecular biology, but starting from scratch

  • Main difficulty: starting from scratch:

    [ ] sticky fingers

    ] ] difficult self-reproduction (maybe that is fortunate …cf “grey goo”)

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An Illustration of Attitudes:

  • When an exaggeration in favor of nanotechnology occurs, nobody complains (cf. “utility fog -> “Arabian jinn”, nanomedicine etc.)

  • When a (possibly) exaggerated worry is expressed, the reaction is swift and venomous (cf. “grey goo”)

  • Recall: “when a scientist says that something can be done, she is usually right.

    “When a scientist says something cannot be done, he is usually wrong”.

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Present Status

  • Rapidly developing field

  • Some interesting but not really useful demonstrations

  • Mostly progress in instrumentation (e.g. optical tweezers”)

  • Concrete success with carbon Buckeyballs and with nanotubes (“Artificial microtubules””)

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Brief Notes on Computer Science

  • There is (unbeknownst to most users) a “machine language” beneath all computing:

  • Bits, bytes, words

  • Instruction set: example: OPCODE A1 A2

    (so 113475 means add content of memory location 34 and location 75, and put the result into location 75;

    or 550078 might mean: go to location 78 and execute the instruction which is there …)

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Programming and Clicking

  • “High-level computer languages”:

    FORTRAN, C, C++, C-sharp, Java, …

    Then: GUI (graphical user interface) ->

    click click click (and nobody knows “how it works”)

    Then: Internet and WWW: even more clicking, and a new meaning to the old problem:

    Data -> Information -> Knowledge -> Wisdom

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Prospects for the Future:

  • Moore’s “law”: doubling of “performance” every 2 years

    => in 20 years: factor of 1,000, in 40 years, factor of 1,000,000

  • Where is the quantum-mechanical limit?

  • But then: Quantum Computing?

    (Richard Feynman, again !!!)

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Date Chip Transistors MIPS clock/MHz

[1965 none ( vacuum tubes ) 0.006 ]

Nov 1971 4004 2300 0.06 0.1

Apr 1974 8080 6000 0.64 2

Jun 1978 8086 29000 0.75 10

Feb 1982 80286 134000 2.66 12

Oct 1985 386DX 275000 5 16

Apr 1989 80486 1,200,000 20 25

Mar 1993 Pentium 3,100,000 112 66

Nov 1995 Pentium Pro 5,500,000 428 200

2000 Pentium 4 4.107 1500 1500

soon 109 24000 24000

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Quantum Computing on one slide:

main “trick”: Quantum parallelism:

(recall the Schrodinger Cat: Ψ =  +  )


00000……0 +

00000……1 +

…….. +

00001……1 +

00011……. +

……. +


e.g. a 300-Qbit quantum computer will perform

2300 ~ 10100 operations simultaneously

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RSA-640 is factored!

Decimal Digits: 193


The factoring research team of F. Bahr, M. Boehm, J. Franke, T. Kleinjung continued its productivity with a successful factorization of the challenge number RSA-640, reported on November 2, 2005. The factors [verified by RSA Laboratories] are:



1900871281664822113126851573935413975471896789968 515493666638539088027103802104498957191261465571

The effort took approximately 30 2.2GHz-Opteron-CPU years according to the submitters, over five months of calendar time. (This is about half the effort for RSA-200, the 663-bit number that the team factored in 2004.)

Further progress exponentially more difficult.

The difficulty for Quantum Computers is non-exponential.

but there are other difficulties: decoherence  (best accomplishment so far: 15)

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Brief Notes on Artificial Intelligence

  • As with nuclear fusion, a breakthrough is always behind the next corner

  • A brute-force approach: the chess machines

  • The case of professor Cope

  • It seems likely (to VC, at least) that real breakthrough will come, if ever, from massive parallelism

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Brief Notes on Robotics

  • This was the main topic of the Stanford Colloquium

  • Practical applications are already numerous (factories, planetary exploration; military, …)

  • This is the dream/nightmare of many (i.e. either:

    ” we will become one with robots”

    or: “ the robots will take over”)

    (see Moravec / Kurzweil / transhumanists )

  • This is also, right now, not very high on my list (i.e. I believe it will require a breakthrough in AI)

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  • The rate of progress is breathtaking

  • The present and potential benefits are enormous

  • The dangers are commensurate

  • There is a Chinese curse which says "May he live in interesting times." Like it or not we live in interesting times. They are times of danger and uncertainty; but they are also more open to the creative energy of men than any other time in history.

    Robert F. Kennedy

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Notes on the International Aspects

  • Two 9/11 speeches (one drafted by VC)

  • How naive is that?

  • UN: reform/rebuild/replace of reject?

  • UN membership, Tuvalu vs. World Bank

  • Troubles with the Security Council

  • Example of Inter. Atomic Energy Agency

  • Example of the EU convention against torture

  • Example of the “replace” option: Federation of Democratic Nations ?

  • Example of thinking “out of the box”: BMD

  • Do we, occasionally, stumble upon the Truth?

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Overview of International Affairs

  • Peace of Westphalia: (1648) ended the Thirty Years' War ; the first modern diplomatic congress; new order in central Europe based on the concept of national sovereignty.

  • WWI: a sheer madness. 1914 to 1918. 20 million dead. German &Austria-Hungary&Ottoman… empire

    vs. France&Great Britain&Russia&USA

    Outcome: 1) Treaty of Versailles (its enforcement -> Hitler !!!)

    2) League of Nations: 1920 – 1946. Overall, a failure.

    WW II: 1937 – 1945. 60 million dead.

    Nazi Germany&Fascist Italy & Imperial Japan

    Vs. France&Great Britain&Soviet Union

    United Nations: 1945 – present

    A General Assembly of 192 member states (China(1 billion) = Tuvalu (10,000) = 1 vote each)

    Security Council with 5 veto-carrying powers (US, Russia, China, UK, France)

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Fellow citizens:     

On September 11, United States, as well as citizens of many other countries suffered a grievous loss in a terrorist attack by a group of religious fanatics. Almost at the same time, a smaller scale but perhaps even more ominous  was the terrorist mailing of anthrax-laden envelopes, unleashed probably  by a single, technically capable but mentally deranged person.      These events reminds us, if it was necessary, that we have entered a new era. Due to advances in science and technology, the capability of causing extreme harm is, or will soon be, in the reach of small groups or even individuals. This has been called "Knowledge-Enabled Mass Destruction", and if unchecked, it will bring about even much larger suffering, perhaps even large scale, catastrophic events. This can be caused  not just by terrorists, but also accidentally or by a miscalculation.       It will be very difficult to prevent this from happening. People will always have grievances, and technological means of terror will be available. The United States has currently the military power to defeat any hostile or rogue state, but it is not possible to fight small groups or individuals with tanks and missiles. Much thoughtful and sustained effort will have to go into this crucial effort. Above all, the rule of international law has to be strengthened, so that we have tools to fight this new kind of struggle.

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The obvious candidate for this is the United Nations, which after all was created after WW2 to enable nations to solve their problems without wars. But the United Nations needs fundamental reforms. The current structure includes 40 mini-states with less that 1 million citizen each, as well as states hundred- or even thousand-times bigger. The main decisions are supposed to be taken, unanimously, by an archaic Security Council. It may turn out that the United Nations' structure is too flawed, in which case we must start from scratch.    Of course, the United States will find out and bring to account those responsible for the recent attacks. At the same time, and with the same urgency, we will use all our power and weight to find solutions to the problem of strengthening the international law, and how to deal with the problem of Knowledge-Enabled mass Destruction. As a start, I am proposing that Congress pass a legislation allocating  a meaningful budget  to create Institutes of Foresight and Centers for Strengthening International Law at major Universities as well as federal agencies. This program should involve our top scientists as well as scholars from the Humanities and political and military leaders, and we welcome cooperation from all countries of good will. The problem is difficult, but together we have a chance of creating a better and safer world.

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Fellow citizens,

On September 11 our nation  was attacked by evildoers. Since that day we are at war with terror. This war has been started by others, but it will end at the time of our choosing. Make no mistake: we will prevail. All countries have to choose: either they are with us, or they are with the terrorists. We will smoke out Osama, dead or alive. The evil dictator Saddam, developing weapons of mass destruction and supporting terrorists, has 48 hours to get out of Iraq. Syria and Iran will need a regime-change, too, and we will figure out what to do about North Korea and others. All this will be done by Coalitions of the willing, each of them under our leadership - the United Nations will be permitted to engage in humanitarian effort. This will be an American Century - may God bless the United States of America.

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Call It the U.N. Commission on Sustainable DictatorshipsBusiness as usual as Zimbabwe takes a seat.By Claudia Rosett, National Review Online, May 13, 2007

With Zimbabwe elected Friday to chair the United Nations Commission on Sustainable Development, we now have the latest poster-child for the usual U.N. Orwellian abuse of the noble mandate, glorious goals, and all those good things …There is by now every sign that the endless production of reports, proposals, and strategies for U.N. reform … serves chiefly to produce new programs, projects, and initiatives, coupled with fresh U.N. demands for money. … Put together, the 13 states listed above, despite including Security Council Permanent-Five veto-wielding movers and shakers Russia and China, pay a grand total of 4.941 percent of U.N. core assessed dues. That’s less than one quarter of the 22 percent paid by the U.S …

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What Is To Be Done (again …)

  • Very modest example:

    make the General Assembly meaningful by grouping member states into units no smaller than, say 50 million (e.g.: Poland + Czech Rep. + Slovakia

    Or 40 smallest states -> Microstate Federation)

    Much more difficult:

    make Security Council meaningful

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Do we, occasionally, and temporarily,

stumble upon the Truth?

We stand today at a unique and extraordinary moment. … . Now, we can see a new world coming into view. … A world where the United Nations, freed from cold war stalemate, is poised to fulfill the historic vision of its founders.

The (former) US President George H.W.Bush,

reacting to the 1st Gulf War

“The gravest danger our Nation faces lies at the crossroads of radicalism and technology.”

National Security Strategy 2002

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Eve and Klebsiella Puzzles

  • Eve and Adam: If something sounds too good …. The famous philosopher made an elemntary error in his logic argument. So no, “logic” does not replace years painstaking research

  • Klebsiella: If something sounds too bad ….:

  • If true: I would have known about it

  • In fact: everyone would have known – this would even be – maybe – the warning event we might need to see the urgency of the Basic problem

  • So it triggered my detector

  • 15 minutes on www has shown that it is all bogus: an overinterpretaion of an experiment by an inexperienced graduate student and an eager, activist professor

  • Lesson 1: such false alarms are very damaging

  • Lesson 2: keep improving your detector

  • Consolation: Evangelical Scientists Refute Gravity

  • (also: Cloned scientists testify in Congress)

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