HDTenEightyP/NetNews huggingface dataset:
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: Mattel protest
Date: 5 Oct 92 16:39:44 GMT
Article-I.D.: murdoch.1992Oct5.163944.15794
Distribution: usa
Organization: University of Virginia

In article <1992Oct5.084600.26398@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:
>jmorzins@grumpy.helios.nd.edu (jacob morzinski) writes:
>: 
>: A friend mailed me this message today.  I wasn't sure if it had been seen
>: in this group yet, so I decided to post it just in case.
>: 
>: 
>: ----------------------------Original message----------------------------
>: 
>: From reed@owlnet.rice.edu Sun Oct  4 17:21:34 1992
>: Date: Sun, 4 Oct 92 16:28:33 CDT
>: From: Kevin Niles Reed <reed@owlnet.rice.edu>
>: 
>: 
>: I promise.  I called.  They really are making such a doll.
>: PLEASE call and bring these people back to the real world.
>: ----------------------------Original message----------------------------
>: 
>: Regarding the message below, I called the number given, and they con-
>: firmed that a doll REALLY is being made which says "math class is tough"
>: PLEASE, call and register your complaint.  They really do count.
>
>
>Implicit in your outrage is the assumption that if Barbie finds math
>class difficult, she will thereby be dissuaded from taking said class.
>In short, Barbie is a wimp who is unable to meet a challenge. This whole
>anti-Mattel campaign is an affront to the staying power of women
>everywhere.

     It is also an affront to the intellegence of women and girls.

     They are so stupid that a ersatz statement from the mouth of a 
     plastic bubblehead irretrievably alters their worldview, poisoning
     them against math forever (I don't recall Barbie mentioning science
     in her little encyclical).  

     If y'all feel it necessary to 'do something' about the paucity of
     women in the physical sciences, then go to the middle schools
     and *teach* math to them in an interesting and wonderful way.  

     However, don't be mislead into thinking that overall numbers
     of mathematicians will change unless the profession pays as 
     well as medicine or law.  There seem to be plenty of women in
     those demanding fields. 

     Also, for most, law school and medical school are tough.

                               dale bass
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
Newsgroups: sci.physics
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: Questions of transparency
Organization: University of Virginia
Date: Thu, 1 Oct 1992 04:48:56 GMT

In article <1992Oct1.010445.13988@u.washington.edu> whit@milton.u.washington.edu (John Whitmore) writes:
>In article <1992Sep25.073432.29995@hplb.hpl.hp.com> davids@spira.bri.hp.com (david sixsmith (contractor)) writes:

>>2. What is the mechanism which makes the speed of light lower when travelling
>>in such a medium as opposed to traveling in a vacuum ?
>
>	Entrainment of charge.  Free (or nearly free) charges are
>moving inside the medium in response to the electric excitation,
>so that the energy in the wave is not entirely field energy,
>but includes kinetic energy and binding energy of the charges,
>so that the wave equation is significantly altered.
>	One could (equivalently) note that excitations of the
>charge give rise to a phase-shifted response wave, and the sum
>of the incident wave and the response is a slower-moving
>composite wave.

    I always found it interesting that "The incident wave may therefore 
    be regarded as extinguished at any point within the medium by 
    interference with the dipole field and replaced by another wave with 
    a different velocity (and generally also with a different
    direction) of propagation (Born and Wolf, p. 100)."  So actually, 
    there 'aint' no incident wave inside the medium since the medium
    conspires to identically cancel the incident wave.

                            dale bass
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
Newsgroups: sci.physics,rec.pets.cats
From: schroede@bnlux1.bnl.gov (gary l. schroeder)
Subject: Re: Radioactive Cat: How Dangerous is She?
Organization: Brookhaven National Laboratory, Upton, NY 11973
Date: Fri, 25 Sep 1992 18:38:24 GMT

In article <+btn-xl.badboy@netcom.com> badboy@netcom.com (Jay Keller) writes:

>I have some more facts to add to the discussion.  The isotope in question is,
>as many have suggested, I-131 with a half-life of approximately 8 days.  The
>cat is first injected with a small dose of Technetium which allows a scan to
>be done to evaluate the situation.  Then the Iodine dosage is determined and
>it is administered.  At this point the cat remains in the hospital for about
>a week.

>I am told that the state of California forbids them to release the cat until
>it is emitting less than 2 mR/hr.  

Interesting.

>What that means I don't know, but I'm sure someone here will.  Is it
>milliRoentgens, milliRads, milliRems, or milli-something-elses?  I suspect that
>it is nothing to worry about.  The people working at the clinic are exposed to
>several of these hot cats every day and seem to feel that they aren't in any
>danger, based on monitoring their personal dosages.

That's 2 mR/hr as in _milli-roentgens_.  This is roughly equivalent to 2
millirem/hr.  (Roentgen is a measure of absolute exposure, rem is a unit
of dose.)  To give you a comparison, in the United States, radiation
workers are allowed to recieve 5,000 mrem in a year.  It is assumed that
at or below this level of exposure, no deleterious health effects will
be observed.  To give you another comparison, we all recieve about 150 -
200 mrem per year from background radiation sources (even up to 270
mrem/yr in Denver, Colarado).

You also have to bear in mind that we're dealing with an 8 day half-life
isotope, if we take excretion into account, the _effective_ half-life is
even less than this (probably a lot less).  So, kitty won't be reading 2
mR/hr for long after she leaves the hospital.  Additionally, you'd have
to be hugging your cat all the time to constantly recieve 2 mrem/hr.  I
assume that they measure the cat at contact, not at a distance.  You'll
probably be several feet or even yards away most of the time and
radiation intensity drops off as 1/distance^2.

Basically, don't sweat it.  The rules are pretty strict on these things
and they wouldn't be giving you a pet back that was going to threaten
your health.


>I will ask about taking iodine supplements to avoid any uptake of the I-131.
>Thanks to the person who suggested this.


-- 
------------------------------------------------------------------------
Gary L. Schroeder  		|  
schroede@bnlux1.bnl.gov         |             Boo. 
Brookhaven National Laboratory  |
From: tolman%asylum.cs.utah.edu@cs.utah.edu (Kenneth Tolman)
Subject: Thermo question for you
Date: 1 Oct 92 22:38:58 MDT
Organization: University of Utah, CompSci Dept

Hello, I am attempting to understand the thermodynamics for this
simple system, if you could tell me the relative entropies of the following
states it would be very helpful.

There are two spheres in the following area divided into "macrostates" and
"microstates":

-------------
|     |     |
|     |     |
|     |     |
-------------
|     |o    |
|     |     |
|     |   o |
-------------

The bottom right corner is a special state, the others are not interesting.
The probability of it being in this state is 1/16... what is its entropy?


Now consider the system at some time later:

-------------
|     |  o  |
|     |     |
|     |     |
-------------
|     |o    |
|     |     |
|     |     |
-------------

What is the entropy of this, and why?  


Thanks for any help, responses would be very helpful!  Thanks.
Newsgroups: sci.physics
From: firth@sei.cmu.edu (Robert Firth)
Subject: Re: Quantum Zeno Effect, Part 1.
Organization: Software Engineering Institute
Date: Mon, 5 Oct 1992 12:30:02 GMT

In article <1992Oct3.134653.20562@oracorp.com> daryl@oracorp.com (Daryl McCullough) writes:

[a neat article on the quantum zeno effect - thanks, Daryl]

Just one minor point: I don't think this effect can be used to slow
down radioactive decay.  That's an exponential process, ie if the
atom is undecayed at time 0, then the probability it is still
undecayed at time t is

	P(t) = exp(-kt)

where k = log2/halflife.  So, if we observe the atom at time t and
again at time 2t, the probability we will observe it undecayed the
first time is exp(-kt), and, presuming this "resets the clock", we
get the same probability for the second observation.  So the joint
probability that it is undecayed both times is

	P(t) . P(2t)|P(t) = exp(-kt) . exp(-kt) = exp(-2kt)

But if we simply leave it alone for time 2t, and then observe it
once, we get

	P(2t) = exp(-2kt)

which is the same answer. (It's also pretty easy to show the converse,
that exponential decay is the only process unaffected by intermediate
observation.)

However, as I said, that's a minor point.  Your major point is that the
act of observing a system, and finding it seemingly unchanged from a
previous observation, can indeed affect the subsequent behaviour of the
system.  In other words, a "null observation" has an effect on the
thing observed.

Ah, but on *what* does it have an effect?  Not on the perceptible atom,
which is seen to be unchanged, but on the imperceptible, and evolving,
wave function, whose evolution has been perturbed.

Yes, food for some very deep thought.
From: jlg@cochiti.lanl.gov (Jim Giles)
Newsgroups: sci.physics
Subject: Re: Defining local, causal etc., was: Hidden variable theories
Date: 2 Oct 92 19:36:06 GMT
Article-I.D.: newshost.1992Oct2.193606.995
Organization: Los Alamos National Laboratory

In article <1992Oct2.013142.25298@unixg.ubc.ca>, ramsay@unixg.ubc.ca (Keith Ramsay) writes:
|> In article <1992Sep29.170356.13002@newshost.lanl.gov> 
|> jlg@cochiti.lanl.gov (Jim Giles) writes:
|> |It is not possible to distinguish between wavefunctions that are
|> |hypothetical entities and  wavefunctions which are real objects.
|> |Not empirically.  Therefore, their introduction violates Occam's
|> |razor. 
|> 
|> How do you distinguish between "hypothetical entities" and "real
|> objects" in any other case?

If you can show me an experiment which can be (at least hypothetically)
performed which yields a different result if "wavefunction collapse"
is reified than it does if it is not even mentioned, then I'll consider
the question of the existence of such an event.  The fact is, QM works
*without* "collapse" even being mentioned.  The wavefunction predicts
a certain probability distribution and (if you measure enough events)
that's the distribution you see.  The wavefunction is, therefore, a 
good *descriptive* model of the statistical behavior of QM systems.
Like all other descriptive models, it may or may not be even remotely
related to any *explanatory* theory which later arises.

The measure of reality is independent verification.  If you can't
independently verify something (not even hypothetically), then 
discussion of its existence is mysticism.  If it is verifyable,
but only hypothetically and not by present technology, then
its existence is pure speculation.  Even the supporters of
the "wavefunction collapse" interpretation are quick to state
(even proudly) that these events are not observable - not even
hypothetically.

-- 
J. Giles
From: Emory.F..Bunn@mailbox.bison.mb.ca (Emory F. Bunn)
Newsgroups: sci.physics
Subject: Re: How old is the universe?
Date: 24 Sep 92 23:19:05 CST

Organization: /etc/organization

Somebody (I can't tell who anymore) wrote

>>>A typical closed universe exists for a plank time.

And David Ring wrote:
>Of course such a special universe as ours must eventually expand until you
>can claim rho/rho0 to be only 10%. The question is whether a _typical_ universe
>will do that.

I've deleted huge amounts of stuff, because this thread raises a bunch of
separate issues, and I only want to comment on one:  The question is 
what is meant by the phrase "a typical Universe"?  Presumably, a statement
like "A typical Universe has a lifetime of x" means that if you take
a large ensemble of Universes, drawn from some random distribution of
possible sets of initial conditions, some significant fraction of them
would have lifetimes not too different from x.  What bothers me about
this is that there is no natural measure one can impose on the set
of possible initial conditions for Universes in order to make that
statement meaningful.

Let me be more specific.  People always raise the argument that if
there's not some physical principle requiring Lambda to be very small,
then it should have "typical values" of order 10^120 times larger
than the maximum allowed by observations in our Universe.  This is a
"fine-tuning problem."  I refuse to be bothered by such a problem,
since the people who make this argument can't even formulate their
claim in a precise way (to say nothing of forming an argument to
support it).  

You can't make convincing statements about the properties of "a typical
Universe" for two reasons.  The less important (IMHO) of the two is
that we only have one Universe to look at, so we have lousy statistics.
What's far more troubling to me is that statements of this kind are 
meaningful only if there exists a measure on the space of possible
Universes (since only in that case can we define probabilities).  It's
not just that there is no single natural choice for such a measure;
there aren't even any possible choices of measure.  (The space of
possible Universes is "too big" for measure theory to deal with.)

Thanks for listening.  Every once in a while I have to get these
heretical views off my chest.  I'm going to go back to my
maximum-likelihood analyses of cosmological simulations now, blithely
free of qualms about their meaningfulness.

-Ted

 * Origin: The Electronic Mailbox (1:348/7.0)
From: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr))
Subject: Re: Hannu, the Wood-Duck (was: STRUCTURE OF TIME)
Organization: National University of Singapore
Date: Sat, 3 Oct 1992 01:29:06 GMT

What the hell is a wood-duck?
Newsgroups: sci.physics
From: bhv@areaplg2.corp.mot.com (Bronis Vidugiris)
Subject: Re: Understand...!!!!
Organization: Motorola, CCR&D, CORP, Schaumburg, IL
Date: Thu, 1 Oct 1992 22:56:19 GMT

In article <1992Oct1.044951.18999@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:

)I am a serious person with a vast store of good will. But you know that
)baloney is not a clock because you know that it doesn't measure time.
)That's because you know that time exists independently of devices used
)to measure it. It's about time [so to speak] to drive a stake [or is
)that steak?] through the heart of operationalism. .

Well, anyone who can make *that* obnoxious of a pun can't be all bad :-) :-)

Anyway, I don't agree about the merits of operationalism (if that's the right
term). I find it to be very useful.  In fact, I think some of the failure of
the discussion of QM in more general (and less operational) terms here on
the net is a minor, but relevant, example of the merits of this point of
view.

Newsgroups: sci.physics
From: prim!dave@germany.eu.net (Dave Griffiths)
Subject: Re: Question about electron spin
Organization: Primitive Software Ltd.
Date: Mon, 28 Sep 1992 17:43:43 GMT

In article <10910@sun13.scri.fsu.edu> jac@ds8.scri.fsu.edu (Jim Carr) writes:
>In article <1992Sep27.185539.594@prim> prim!dave@germany.eu.net (Dave Griffiths) writes:
>>I've just been reading Roger Penrose's explanation in the Emperor's New Mind
>>of the EPR experiment. In this he claims that it is possible to measure the
>>spin of an electron in three different directions at 120 degrees to each
>>other and obtain the result YES, the spin of the electron is aligned in
>>that direction for each measurement. Surely this is incorrect? He has already
>
>Nope.  It is correct. 
>
>>shown that if you measure the spin in one direction and get the answer YES,
>>then there is a probability of (1 + cos 120)/2 = 1/4 that a measurement at
>>120 degrees to this will also give the answer YES. Fine. But surely, with 
>>the wave function having collapsed, it's not possible for three measurements 
>>at 120 degrees to each other _all_ to give YES?
>
>Why not?  The wavefunction was "collapsed" in the original direction 
>before you ran it through the first 120-degree analyzer.  The chance of 
>getting three YES answers from the system described is just 1/4 * 1/4 * 
>1/4 = 1/64 = 1.56%.  
>

No wonder they call it spin. :-) Seems the notion of spin in a particular
direction is a bit meaningless if you can detect it in all three
directions. Your comment about polarizing sheets has almost persuaded me,
however we're dealing there with _aggregates_. I was wondering whether it
was possible to measure the spin of one single electron three times
consecutively and get "spin up" in three directions. If you did such a
measurement at 0, 120 and 240 degrees and got YES each time, and then
measured it at 180 degrees, would there be a chance (1 + cos 60)/2 (ie the
angle between the last measurement at 240 and 180) of now getting a YES,
or does the past history of a measurement at 0 preclude this? Could you
possibly get a YES at 60 degrees, exactly opposite your YES at 240 degrees?

>Is your brain numb yet? 

Yes.

Dave Griffiths
Newsgroups: sci.physics,sci.astro,sci.math,sci.philosophy.tech
From: jk87377@cc.tut.fi (Juhana Kouhia)
Subject: Re: STRUCTURE OF TIME (at numerous requests)
Organization: Tampere University of Technology
Date: Mon, 28 Sep 92 12:50:58 GMT


In article <1992Sep28.091054.1@tnclus.tele.nokia.fi>
hporopudas@tnclus.tele.nokia.fi writes:
>
>     And because this inhuman and hostile environment of science to amateurs
>   I have some doubts that will Hanna-Maria ever become scientist when
>   she grows up. This kind of hostile and unhuman environment could injure
>   her seriously.

Note that you use 'amateur' and 'scientist' words.
This environment is not inhuman for scientist (who does have
some selfcritics (sp?)).

Also, this environment is not inhuman for amateurs.
Figure it out why this environment is inhuman for you.

Also, don't overact -- to me, it looks like you have written
also texts which doesn't allow people be inhuman for you, or?

By the way, is your Structure of Time physically correct?
I have not followed replies by professional physicsists.


Juhana Kouhia
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: 3-polarizer fun
Date: 28 Sep 92 23:46:11 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

|> Surely you have seen (or done, find some friends with
|>Polaroid sunglasses) the experiment where you have crossed (90 degree)
|>polarizers and then insert one between them at 45 degrees and see it
|>go from black to (dim) light.  Same thing with electrons.
|
|This experiment had a very profound influence on me, ...
| I guess that I am easily amused.

Me too.  I keep several 1-inch squares of Polaroid in my desk at home
and try this out on my non-scientist friends every now and then,
because it's such a cool thing.  It usually gets people very
interested.
Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr))
Subject: Re: Mattel protest
Organization: National University of Singapore
Distribution: usa
Date: Mon, 5 Oct 1992 08:46:00 GMT

jmorzins@grumpy.helios.nd.edu (jacob morzinski) writes:
: 
: A friend mailed me this message today.  I wasn't sure if it had been seen
: in this group yet, so I decided to post it just in case.
: 
: 
: ----------------------------Original message----------------------------
: 
: From reed@owlnet.rice.edu Sun Oct  4 17:21:34 1992
: Date: Sun, 4 Oct 92 16:28:33 CDT
: From: Kevin Niles Reed <reed@owlnet.rice.edu>
: 
: 
: I promise.  I called.  They really are making such a doll.
: PLEASE call and bring these people back to the real world.
: ----------------------------Original message----------------------------
: 
: Regarding the message below, I called the number given, and they con-
: firmed that a doll REALLY is being made which says "math class is tough"
: PLEASE, call and register your complaint.  They really do count.


Implicit in your outrage is the assumption that if Barbie finds math
class difficult, she will thereby be dissuaded from taking said class.
In short, Barbie is a wimp who is unable to meet a challenge. This whole
anti-Mattel campaign is an affront to the staying power of women
everywhere.
B
B
B
B
B
B
B
: 
: 
: 
: 
: Kevin
: 
: 
: 
: 
: 		-Jacob Morzinski
: 
:
From: paul@mtnmath.UUCP (Paul Budnik)
Newsgroups: sci.physics
Subject: Re: Simple observation about Quantum Kitty Cats
Date: 1 Oct 92 14:18:28 GMT
Organization: Mountain Math Software, P. O. Box 2124, Saratoga. CA 95070

In article <22592@galaxy.ucr.edu>, baez@ucrmath.ucr.edu (john baez) writes:
> 
> That may be how philosophy works - pitting argument against argument -
> but it's not how physics works; there one pits model against model.
> Just saying "quantum collapse as a physical local process" won't stack
> up against a well-developed formalism that people have successfully
> used for decades.  You need to lay out a precise model of quantum
> collapse as a physical local process and show how one can calculate
> all sorts of things with it.  I.e., you have to match the competition.
> OR you have to get ahold of an experiment that shows the existing formalism
> makes wrong predictions.  

But my formalism makes the same predictions of quantum mechanics with
the exception of tests of Bell's inequality. It is just as important in
science to be clear about what you do not know as is to be clear about
what you do know. We have no idea how the wave function changes when
an observation is made. There is no scientific justification for saying
the change occurs instantaneously throughout space.

The issue I am addressing is the priority that one should give to the
experiment that will decide between these two positions. When you
say, as Daryl, did that there is no hint of a problem in the predictions of
quantum mechanics you are implying that there is a low priority to
doing the experiment properly. You expect to find novel results when you
do accelerator experiments. You do not expect to find them when you
test Bell's inequality. I think there is a compelling scientific argument
that your expectations about Bell's inequality are wrong and the priority
of this experiment should be much higher. 

> That's how the game goes: revolutions in physics do not come easily.

Boy you can say that again. Bell's result is over 25 years old. Tests of
Bell's inequality are almost table top experiments. Maybe it
would cost a few million to do it properly. I cannot believe it would
cost much more. In the mean time billions are spent on particle accelerators
with results that are far less significant in both theoretical and
practical terms.

Paul Budnik
Newsgroups: sci.physics