HDTenEightyP/NetNews huggingface dataset:
From: gunter@csd4.csd.uwm.edu (David O Gunter)
Subject: Probability Question
Organization: Computing Services Division, University of Wisconsin - Milwaukee
Date: Mon, 14 Sep 1992 21:25:28 GMT

A particle is equally likely to be found anywhere on the circumference of a
circle.  Choose some line which passes through the center of the circle to be
a reference axis.  Then the line joining the center of the circle to the 
particle will make some angle, theta, with respect to this axis.

Question:  What is the probability that the angle will lie between theta
and theta + dtheta (dtheta is some increment amount.)

Here are two ways I've tried to tackle the problem:

  First, the total range of theta is 2*Pi, so that the probability should be
proportional to dtheta/(2*pi).  But there are 4 positions around the circle
at which the particle will be at some angle theta w/respect to the axis.  So
it appears that the probability should be

                            2 dtheta
                       P =  ---------
                               Pi

  However, if I think of the problem in another way, I get a different
answer:
  Imagine that we are dealing with only one quarter of the circle.  Now
there is a range of Pi/2 for the theta values, and there is only one
position at which the particle makes an angle theta w/respect to the axis
(one of the sides of the 'pie slice'.)  So the prob. for this piece is
2*theta/Pi.  But since there are 4-quarters, the total prob. is

                                8 dtheta
                          P =  -----------
                                  Pi

Which, if any, of these two methods gives the correct answer?  Or what is
the correct answer?

Thanks.

                        |"How arrives it joy lies slain, and why unbloomed the
david gunter            | the greatest hope ever sown . . ." 
gunter@csd4.csd.uwm.edu |           -Thomas Hardy
gunter@mcs.anl.gov      |               "Hap"                            

-- 
                        |"How arrives it joy lies slain, and why unbloomed the
david gunter            | the greatest hope ever sown . . ." 
gunter@csd4.csd.uwm.edu |           -Thomas Hardy
gunter@mcs.anl.gov      |               "Hap"                            
Xref: sparky sci.physics:14374 rec.pets.cats:10864
From: mvp@hsv3.lsil.com (Mike Van Pelt)
Newsgroups: sci.physics,rec.pets.cats
Subject: Re: Radioactive Cat: How Dangerous is She? <LONGISH>
Date: 9 Sep 92 22:54:26 GMT
Organization: LSI Logic/Headland Technology

In article <ZOWIE.92Sep8014817@daedalus.stanford.edu> zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes:
>One thing to consider is that, even after your cat isn't very
>radioactive, it's still a living being, metabolizing and excreting its
>radioidine.  The stuff will be present mainly in its urine, and
>probably in its other excreta (feces, saliva, etc.).  Radioiodine in
>your environment will be absorbed into *your* thyroid,

Only if you ingest it.  This seems unlikely, even for the most
fanatical cat-lover.

An old high-school friend of mine went to work at a nuclear plant after
he got out of the Navy, and he had a story or two to tell about I131
treatments.  Like the time they had to cordon off the Port-A-Pottie
with radiation hazard signs and guards because someone had their
thyroid done, came to the site, and used their john.  And how they
trace the plume of I131 downstream from the sewage treatment plant
whenever anyone in the city gets a thyroid treatment.

-- 
Mike Van Pelt                  An oxymoron, I think. The reality of Usenet."
LSI Logic/Headland Products             --  Dan'l Danehy-Oakes                    
sun!indetech!hsv3!mvp
mvp@hsv3.lsil.com
Xref: sparky sci.physics:14724 sci.math:11523
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Quantized Length
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Thu, 10 Sep 92 18:27:17 GMT

In article <5322@tuegate.tue.nl> johan@blade.stack.urc.tue.nl (Johan Wevers) writes:
>cannon@scs.unt.edu (Dustin Cannon (Lab 3460)) writes:

>>	I liked this because it also solves a rather disturbing idea one of 
>>my professors once said, which was that as two point charges come in contact 
>>with each other they have infinte potential energy due to 1/r.  This, he 
>>said, was in his mind a proof of God's existence.
>
>Who told you this nonsense? Renormalisation calculus in quantum field
>theory knows how to deal with these infinities, and a few time ago
>John C. Baez posted a message in which he explained that, even without
>QM, the mass would be finite: because gravitation also contributes to
>the rest mass, and mass also contributes to the gravitation, we get:
>
>m(r)=m_0 + e^2/r - Gm^2(r)/r
>
>Because in the third term on the left-hand side we have m(r) instead
>of m_0 , we receive in the limit r->0: m(r)= e/\sqrt{G}. Finite.

Things aren't quite so cut-and-dry - this argument is very cute but
rather dubious since it ignores special relativity, much less general 
relativity, and also ignores quantum mechanics.  Typical renormalization
theory arguments ignore general relativity (and indeed, gravity
altogether) but take special-relativistic quantum theory into account.
Also, typical renormalization theory arguments are nonrigorous and have
been the subject of intense investigation and puzzlement ever since
their invention in the 40's.  (Or whenever.)  So I wouldn't say we know
for sure how to deal with these, although in practice most of the time
we pretend we do.

>I don't understand what this has to do with a god.

Yes, this is the main point!  It has absolutely nothing to do with gods.

>Quantum gravity and superstring deal with quantisized length, but we
>don't understand both of these theories yet complete.

Folks, it's not quantitized, or quantisized, it's just quantized.
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: It's Down to the Last Blank Check
Organization: MIT Department of Mathematics, Cambridge, MA
Distribution: na
Date: Thu, 10 Sep 92 02:14:16 GMT


>>Society needs to negotiate a new contract with the scientific community.
>>This contract must be rooted in the pursuit of explicit, long-term
>>social goals, such as zero population growth, reduced generation of
>>waste, reduced consumption of non-renewable resources, less armed
>>conflict, less dependence on material goods as a gauge of wealth or
>>success and greater opportunity for self-realization for all human
>>beings.  A new contract will measure the value of reasearch and
>>innovation not by number of publications or citations or patents, but by
>>progress toward these specific goals.  

>I submit that some or all of these goals are beyond the purview of
>science -- perhaps beyond any attempt at governmental management.

>Perhaps John C. Baez (a sci.physics regular whose postings I usually 
>find reasonable) cut too much when he "left out some paragraphs that 
>would show how he [The Hon. George E. Brown, Jr.] got to his conclusions."  
>Wonder if there's anything left in the L.A. Times vending machine...

>--Joe

Hmm.  Stating that you "usually" find my postings reaonable sounds
like a subtle way of saying that you don't find this one reasonable. 
I would submit that the reason is because I didn't write the part you
object to!  

I didn't mean to imply that I agreed with *how* the Rep. George E. Brown, Jr. 
got to his conclusions.  Nor that I disagreed.  I sort of agree, sort
of disagree, etc. etc. etc..  I just wanted to pass this one
on without endorsing this fellow's opinions.  Since he's in power his
opinions matter.

(He may be honorable, but he's not The Honorable.)

.
Xref: sparky sci.physics:14588 sci.math:11365
From: gjm11@cus.cam.ac.uk (G.J. McCaughan)
Newsgroups: sci.physics,sci.math
Subject: Re: Report on Philosophies of Physicists
Date: 13 Sep 92 22:09:40 GMT
Organization: U of Cambridge, England

In article <1992Sep13.045114.17931@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:

>was impressive given Koenig's very high reputation.)  A month later
>Zermelo was able to prove Cantor's continuum hypothesis assuming the
>Axiom of Choice, but despite the further uproar Zermelo's result
>produced, the eventual upshot was more to call AC into question than to
>resolve the continuum hypothesis.

Are you sure about this? I mean, you don't say his proof was wrong or
anything, but I'm completely certain that not(CH) is consistent with AC.
In fact I can prove it. So errrm, do you mean that Zermelo was able to
think (wrongly) that he had proved CH using AC? or are we talking about
a radically different set theory to the one I'm thinking of? or what?
-- 
Gareth McCaughan     Dept. of Pure Mathematics & Mathematical Statistics,
gjm11@cus.cam.ac.uk  Cambridge University, England.    [Research student]
Xref: sparky sci.physics:14702 sci.math:11496
Newsgroups: sci.physics,sci.math
Subject: Re: Elevator mayhem
From: mcirvin@husc8.harvard.edu (Mcirvin)
Date: 15 Sep 92 19:31:11 GMT

hsieh@math.toronto.edu (Paul Hsieh) writes:

>Well, I've though about this once (not too seriously) and figure that if your
>timing is good enough that you could jump up at the last second before impact
>to actually reduce the speed.  Then you could end up with method 2) with 
>lesser impact.  :)  I don't know if there is any merit to what I've just said
>but I'm wondering if there is anything fundamentally flawed with it (besides
>the amazing timing that would be required).

There is a fundamental flaw... Think about what happens when you come
back down at the end of your jump.  Remember, you've jumped off of a
floor that is traveling downward at high speed, and you land on a floor
that has stopped moving!  All you've done is delay the injury a fraction
of a second. 
-- 
Matt McIrvin, Cambridge, Massachusetts, USA 
Newsgroups: sci.physics
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Subject: Re: Rotating Bucket of Water in a Gravitation Field...Part #2
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Sat, 5 Sep 1992 00:21:00 GMT

wdb3926@zeus.tamu.edu (BRUTON, WILLIAM DANIEL) writes...
>Doesn't this say that there is some absolute inertia frame that
>the rotation is to be measured from?  This reeks of "ether" so it
>must be incorrect.  Were is my error?

Ahh! Mach's principle, my favorite subject. There is of course not one
special frame but many, related by lorentz transformations. They are the
ones which are 'inertial' relative to the distant stars, in the distant past.
Actually, there is a preferred _rest_ frame too, but that is a consequence
of the homogeneity of the 'primordial soup' (I think) and not a principle
of physics.

If you want to discuss it, my office is 440ENPH.

>I suppose this is some kind of apparent paradox in relativity.  I have
>seen someone give a talk about the "rotating bucket paradox".  But
>the speaker did not seem to clear up the paradox. 		 

Was the talk here at A+M? I don't remember it. Who was the speaker?

Dave Ring
dwr2560@zeus.tamu.edu
Xref: sparky sci.physics:14726 sci.math:11525
From: bruck@mathj.usc.edu (Ronald Bruck)
Newsgroups: sci.physics,sci.math
Subject: Re: Elevator mayhem
Date: 15 Sep 92 23:51:33 GMT
Organization: University of Southern California, Los Angeles, CA
NNTP-Posting-Host: mathj.usc.edu


The idea of a spring at the bottom of the elevator is a new twist on
this old problem.

Which reminds me of a friend who used to work for Otis Elevator...
He claimed that *** no one *** had ever been killed by an Otis elevator...
Maimed and mangled, yes, but never killed...

--Ron Bruck
bruck@mtha.usc.edu preferred
From: jhh@spock.physics.ucsb.edu..ucsb.edu (Jim Horne)
Newsgroups: sci.physics
Subject: Re: Black hole + anti-Black hole = ?
Date: 9 Sep 92 15:08:05 GMT
Reply-To: jhh@cosmic.physics.ucsb.edu.UUCP (Jim Horne)
Organization: UCSB Physics Department

In article <18jgmmINNm4g@smaug.West.Sun.COM> Richard.Mathews@West.Sun.COM (Richard M. Mathews) writes:
>
>Now, it bothers me that Hawking evaporation does not conserve lepton and
>baryon number.  Something related to gravity just shouldn't be fooling
>with such things.  Personally, I think that a TOE will get rid of the
>singularity at the center of a black hole (assuming it doesn't get rid
>of black holes completely), and it will replace the singularity with
>something which does conserve lepton and baryon number.  That would
>mean that black holes would have lepton and baryon numbers, though you
>might not be able to directly measure those until the hole evaporates
>away.
>
>     Richard M. Mathews			Lietuva laisva = Free Lithuania
>					Brivu Latviju  = Free Latvia
>Richard.Mathews@West.Sun.COM		Eesti vabaks   = Free Estonia
>					        WE  DID  IT!!!

Actually there's a neat argument that says that it is okay for a black
hole to violate baryon and lepton number conservation. I heard it
second or third hand, so I'm not sure who originated it, but it may
have been Sidney Coleman.

The idea is this: we know (or at least believe) that baryon number is
violated at high energy. This is the favorite way to explain why the
unierse is made of matter and not anti-matter. A popular energy scale
to assume for the symmetry breaking is around the GUT scale, or about
10^15 or so GeV. In other words, above a certain energy, there lots of
baryon number violating processes.

Now, consider what should happen when we eventually figure out what
string theory is telling us about the nature of the classical
singularity. If the singularity somehow gets smoothed out, the
smoothing will probably be around the Planck scale, so there will be a
blob of Planck scale matter in the middle, instead of a singularity.
Since the Planck scale is a few orders of magnitude above the GUT
scale, matter-antimatter symmetry will be restored in the blob, and
baryon number will be freely violated.

Thus, the fact that black holes violated baryon and lepton numbers
is not a real problem.
------------------------------------------------------------------------
Jim Horne
jhh@cosmic.physics.ucsb.edu
                                       
	     "Mars is somewhat the same distance from the sun, which is
	     very important.  We have seen pictures where there are
	     canals, we believe, and water.  If there is water, there
	     is oxygen.  If oxygen, that means we can breathe."
                                             Dan Quayle, August 11, 1989
From: matt@physics16.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: Why do protons outnumber antiprotons?
Date: 9 Sep 92 00:25:00 GMT
	<25950@dog.ee.lbl.gov> <3SEP199220131399@zeus.tamu.edu>
	<26086@dog.ee.lbl.gov> <4SEP199219360305@zeus.tamu.edu>
	<1992Sep8.225821.12113@sfu.ca> <mcirvin.715995960@husc8>
Reply-To: matt@physics.berkeley.edu
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
NNTP-Posting-Host: physics16.berkeley.edu
In-reply-to: mcirvin@husc8.harvard.edu's message of 8 Sep 92 23:46:00 GMT

In article <mcirvin.715995960@husc8> mcirvin@husc8.harvard.edu (Mcirvin) writes:

> Either
> it's the result of weird initial conditions, or it might be the result
> of Sakharov's conditions being met, with baryon number nonconservation
> coming either from GUT couplings or from the anomalous term in the
> electroweak lagrangian.

The latter possibility seems rather unlikely to me; baryon number
violation in the Standard Model proceeds through topological effects,
and is suppressed by a factor of something like exp(-1/alpha).  This
is tiny enough so that I tend to think of this effect as a theoretical
curiosity that probably has no experimental implications at all.

(Unless, of course, something odd happens at very, very high
temperatures; I've never heard of any suggestions that might be the
case, though.)
--
Matthew Austern                   Just keep yelling until you attract a
(510) 644-2618                    crowd, then a constituency, a movement, a
austern@lbl.bitnet                faction, an army!  If you don't have any
matt@physics.berkeley.edu         solutions, become a part of the problem!
Newsgroups: sci.physics,sci.math
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Report on Philosophies of Physicists
Organization: Computer Science Department,  Stanford University.
Date: Sat, 12 Sep 1992 05:52:47 GMT

In article <1992Sep11.211113.47423@Cookie.secapl.com> frank@Cookie.secapl.com (Frank Adams) writes:
>In article <1992Sep10.205022.15408@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:
>>The problem with Platonism is that the entities discovered by
>>mathematicians depend for their existence on which axioms one assumes.
>>One might think that axioms are beyond question, if only by definition
>>of "axiom".  However it is not obvious to anyone, even today (in fact
>>especially today), what the right axioms should be.
>
>Pardon me for a simple answer to a complex posting, but it seems to me that
>the rest of the argument all depends on this paragraph.  And this paragraph
>does not represent a problem for Platonists, but only for formalists
>pretending to be Platonists.  The hidden assumption is that mathematics
>consists of the results of the working out of the consequences of axioms.
>As a Platonist, I reject this assumption.  (It is true, but beside the
>point, that the overwhelming majority of the body of mathematics can be so
>characterized.)

This affirms your position but does not defend it.

What non-consequences belong to the body of mathematics?
-- 
======================================================| God found the positive
Vaughan Pratt   pratt@cs.Stanford.EDU   415-494-2545  | integers, zero was
======================================================| there when He arrived.
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Why do protons outnumber antiprotons?
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Wed, 9 Sep 92 05:11:52 GMT

In article <1992Sep8.225821.12113@sfu.ca> palmer@sfu.ca (Leigh Palmer) writes:
>I wish to observe that this discussion quickly abandoned the question so
>clearly stated in its title. It seems to me that result is commoner than usual
>in response to this particular question. Could it be that ignorance on this
>subject is as profound as I have always suspected it is?

Sure, if not more so.

You might want to check out Zeldovich's new book, "My Universe".  I'm
not spelling it exactly right; he's the famous cosmologist.  I only
glanced at it but I seem to recall that it contains some ideas about
this problem - as well as a lot of other cool stuff.

In the preface he notes that he does not claim to own this or any other
universe.
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Size of neutrino
Date: 14 Sep 92 23:08:09 GMT

kibler@turing.ICS.UCI.EDU (Dennis Kibler) writes:

>Hi,
>  My seven year old is very interested in sizes and speeds of
>various things around us. Yesterday he asked me how big
>a neutrino was. I have no idea of how to answer him.
>Any help appreciated.

Nobody knows!  The only way (outside of something like string
theory in which particles are treated as extended, floppy
objects) that a particle can have any size at all is for it to
consist of smaller components, as long as relativity holds.
An atom is the size it is because of the distribution of its
electrons, for instance.  In the Standard Model of particle
physics, neutrinos (and electrons!) are treated as truly
fundamental particles, so they have no extension at all;
they are points.  This doesn't cause physicists much worry
since most of them believe that the smooth geometry of space
breaks down anyway at scales below 10^-33 cm, so this picture
of neutrinos as points rests on an approximation.  But it
does appear from the data that the picture of electrons, at
least, as point particles is good to the limit of experimental
precision.  Neutrinos are harder to deal with.
 
>A while back we had the following conversation.

> Son: When the astronauts go outside their spaceship,
>      they can't talk to each other.
> Me: Why is that?
> Son: Because sound goes at 600 mph and they are going
>      at 15,000 mph.
> Me: Hmnn. There isn't any air out is space.
> Son: Well--
>       that's another reason why that can't talk to each other.


>dennis
-- 
Matt McIrvin, Cambridge, Massachusetts, USA 
Xref: sparky sci.physics:14291 rec.pets.cats:10800
From: pdsmith.mitre.org (Pat Smith)
Newsgroups: sci.physics,rec.pets.cats
Subject: Re: Radioactive Cat: How Dangerous is She?
Date: 8 Sep 92 20:56:51 GMT
Article-I.D.: linus.1992Sep8.205651.10774
Organization: The MITRE Corporation

In article <yfpnc!g.badboy@netcom.com>, badboy@netcom.com (Jay Keller) writes:
> 
> One of my cats has a severe case of hyperthyroidism.  In less than a year
> (she's 9) she's lost over half her weight and is literally wasting away due
> to the extremely high metabolism caused by the disease.  At this point she is
> just about skin and bones although she eats 3 meals a day.
> 
> Medical treatment is possible, however the medicine (Tapazole) needs to be
> continued indefinitely, with the likely result of kidney damage (very soon in
> some cases).
> 
> Surgical treatment (thyroidectomy) is also possible, but carries the risk that
> the parathyroid glands will be damaged, leaving the patient with a new serious
> disease in place of the original one.  Obviously surgery is fairly expensive,
> although a few years of Tapazole therapy would probably cost even more in 
> the long run.
> 
> I've received several opinions from experienced veterinarians that the treat-
> ment of choice is radiation therapy.  Radioactive iodine is introduced into the
> cat, it collects in the thyroid, and destroys it.  The cost is about the same
> as surgery, but the opinions I've received indicate that the outcome is likely
> to be much better.
> 
> Finally, my question(s)...
> 
> How much exposure to radiation will my family get after the cat comes back from
> the radioisotope treatment?  I was told that the cat would be hospitalized for
> a few days to allow the radiation to subside.  But I have 2 small children and
> this is a very friendly cat, often staying close to whomever is around, and I
> would like to quantify the risk a bit more if possible.  Am I correct in 
> assuming that we are talking about alpha particles here, and that they only
> have an ionizing effect at a short distance?  If so, how short?
>  
> What questions should I ask of the radiologist?  
> 
> Thanks in advance.
> 
> Regards,
> 
> Jay Keller
> Sunnyvale, California
> 
> badboy@netcom.com
> 
> 
I am no doctor but go with the radioactive stuff to kill the thryoid.  They 
give this treatment to people all the time.  Often the entire thryoid is
killed, therefore the cat will need a daily thyroid supplement which I think
is inexpensive.  Don't worry about the radiation.  I am not sure what element
is used but it probably breaks down fairly quickly.  If they use this stuff
on humans, it cannot be that bad.  The alternative looks gloomy so what do
you have to lose.
Xref: sparky sci.physics:14639 sci.math:11429
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: Why do protons outnumber antiprotons?
Organization: Simon Fraser University
Date: Tue, 8 Sep 1992 22:58:21 GMT

I wish to observe that this discussion quickly abandoned the question so
clearly stated in its title. It seems to me that result is commoner than usual
in response to this particular question. Could it be that ignorance on this
subject is as profound as I have always suspected it is?

Leigh
Newsgroups: sci.physics,sci.math