| Topic: |
Science > Physics |
| User: |
"Don1" |
| Date: |
11 Nov 2005 06:45:49 PM |
| Object: |
Dimensional consistency |
The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displacement (s/t) that it causes is a
constant: Equal to the body's weight (w), divided by the rate (g/2) at
which it will free fall at the location of the weight-scale on which it
is weighed.
This can be written mathematically as m=ft^2/s, and is equal to 2w/g;
so that for m = 1slug we get:
1 slug=1 lbf sec^2/ft=2w/g; which can be reduced to 1 slug=1 lbf
sec^2/foot.
This equation is dimensionally consistent, in that it can be written
forwards, or backwards; without changing its value.
Don
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| User: "Herman Trivilino" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 09:47:02 AM |
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"Don1" <dcshead@charter.net> wrote ...
The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displacement (s/t) that it causes is a
constant:
No, it's quite easy to see that this is not true. Deliver an impulse to
your car while driving at a slow speed of 10 mi/h. Then while driving the
same car at a faster speed of 80 mi/h, apply the same net force for the same
amount of time to deliver the same impulse. In each case the car will speed
up. In the latter case the ratio s/t will be larger (becasue the car will
travel a further distance). So the ratio of the impulse to s/t will be
smaller!
As has been pointed out to you many times, your ideas may satisfy you at
some philosophical level in that they seem to coincide with the way you
think things ought to behave. They do not, however, match the way things
actually do behave.
In other words, they make for a physics that doesn't match what's observed.
That is, a physics that is wrong.
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 12:22:17 PM |
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Herman Trivilino wrote:
"Don1" <dcshead@charter.net> wrote ...
The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displacement (s/t) that it causes is a
constant:
No, it's quite easy to see that this is not true. Deliver an impulse to
your car while driving at a slow speed of 10 mi/h. Then while driving the
same car at a faster speed of 80 mi/h, apply the same net force for the same
amount of time to deliver the same impulse. In each case the car will speed
up. In the latter case the ratio s/t will be larger (becasue the car will
travel a further distance). So the ratio of the impulse to s/t will be
smaller!
If the impulse is smaller, the ratio is the same, and depends on the
knee of the jerk driving;^)
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| User: "Herman Trivilino" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 05:30:47 PM |
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"Don1" <dcshead@charter.net> wrote ...
If the impulse is smaller, the ratio is the same, and depends on the
knee of the jerk driving;^)
True. But you miss the point.
You can arrange a pair of situations where the ratio of the impulse to the
average velocity is the same. That doesn't make the ratio constant in the
general case. Nor does it make it equal to the mass.
It has the dimensions of mass, but it is not equal, or even proportional, to
the mass.
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 09:14:14 AM |
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Don1 wrote:
The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displacement (s/t) that it causes is a
constant: Equal to the body's weight (w), divided by the rate (g/2) at
which it will free fall at the location of the weight-scale on which it
is weighed.
This can be written mathematically as m=ft^2/s, and is equal to 2w/g;
so that for m = 1slug we get:
1 slug=1 lbf sec^2/ft=2w/g; which can be reduced to 1 slug=1 lbf
sec^2/foot.
This equation is dimensionally consistent, in that it can be written
forwards, or backwards; without changing its value.
Don
For m = 1 gram we get: 1 gram=1 dyne sec^2/cm=2w/g; where 2w/g is equal
to two times 981 dynes divided by 981 cm per sec^2.
For m = 1 kilohram we get: 1 kilogram=1 newton sec^2/m=2w/g; where 2w/g
is equal to two times 9.81 newtons divided by 9.81 m per sec^2.
These equations are dimensionally consistent, in that they can be
written forwards, or backwards; without changing their value.
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| User: "Herman Trivilino" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 05:36:44 PM |
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"Don1" <dcshead@charter.net> wrote ...
For m = 1 gram we get: 1 gram=1 dyne sec^2/cm=2w/g; where 2w/g is equal
to two times 981 dynes divided by 981 cm per sec^2.
Do you see that two times 981 dynes divided by 981 cm/sē is 2 grams?!
Do you see that 1 gram is not equal to 2 grams?
For m = 1 kilohram we get: 1 kilogram=1 newton sec^2/m=2w/g; where 2w/g
is equal to two times 9.81 newtons divided by 9.81 m per sec^2.
These equations are dimensionally consistent, in that they can be
written forwards, or backwards; without changing their value.
Yes. The equation 2=1 is just as valuable as the equation 1=2.
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 06:56:22 PM |
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Herman Trivilino wrote:
"Don1" <dcshead@charter.net> wrote ...
For m = 1 gram we get: 1 gram=1 dyne sec^2/cm=2w/g; where 2w/g is equal
to two times 981 dynes divided by 981 cm per sec^2.
Do you see that two times 981 dynes divided by 981 cm/s2 is 2 grams?!
Do you see that 1 gram is not equal to 2 grams?
For m = 1 kilohram we get: 1 kilogram=1 newton sec^2/m=2w/g; where 2w/g
is equal to two times 9.81 newtons divided by 9.81 m per sec^2.
These equations are dimensionally consistent, in that they can be
written forwards, or backwards; without changing their value.
Yes. The equation 2=1 is just as valuable as the equation 1=2.
Yes; they are both garbage!
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 07:22:09 PM |
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Don1 wrote:
Herman Trivilino wrote:
"Don1" <dcshead@charter.net> wrote ...
For m = 1 gram we get: 1 gram=1 dyne sec^2/cm=2w/g; where 2w/g is equal
to two times 981 dynes divided by 981 cm per sec^2.
Do you see that two times 981 dynes divided by 981 cm/s2 is 2 grams?!
Do you see that 1 gram is not equal to 2 grams?
For m = 1 kilohram we get: 1 kilogram=1 newton sec^2/m=2w/g; where 2w/g
is equal to two times 9.81 newtons divided by 9.81 m per sec^2.
These equations are dimensionally consistent, in that they can be
written forwards, or backwards; without changing their value.
Yes. The equation 2=1 is just as valuable as the equation 1=2.
Yes; they are both garbage!
Unless they have units!!
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 07:19:29 PM |
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Don1 wrote:
Don1 wrote:
The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displacement (s/t) that it causes is a
constant: Equal to the body's weight (w), divided by the rate (g/2) at
which it will free fall at the location of the weight-scale on which it
is weighed.
This can be written mathematically as m=ft^2/s, and is equal to 2w/g;
so that for m = 1slug we get:
1 slug=1 lbf sec^2/ft=2w/g; which can be reduced to 1 slug=1 lbf
sec^2/foot.
This equation is dimensionally consistent, in that it can be written
forwards, or backwards; without changing its value.
Don
For m = 1 gram we get: 1 gram=1 dyne sec^2/cm=2w/g; where 2w/g is equal
to two times 981 dynes divided by 981 cm per sec^2.
For m = 1 kilohram we get: 1 kilogram=1 newton sec^2/m=2w/g; where 2w/g
is equal to two times 9.81 newtons divided by 9.81 m per sec^2.
These equations are dimensionally consistent, in that they can be
written forwards, or backwards; without changing their value.
A good site for dimensional analysis is
<http://sst-web.tees.ac.uk/external/U0000504/Notes/labwork/LabManual/Units.html>
Where it says: "All equations relating physical quantities should be
dimensionally consistent. That is when the units on both sides of an
equation are worked out they should be identical."
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| User: "Herman Trivilino" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 09:30:27 PM |
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"Don1" <dcshead@charter.net> wrote ...
For m = 1 gram we get: 1 gram=1 dyne sec^2/cm=2w/g; where 2w/g is equal
to two times 981 dynes divided by 981 cm per sec^2.
A good site for dimensional analysis is
<http://sst-web.tees.ac.uk/external/U0000504/Notes/labwork/LabManual/Units.html>
Where it says: "All equations relating physical quantities should be
dimensionally consistent. That is when the units on both sides of an
equation are worked out they should be identical."
When we write 1 gram = 2 grams, we have an equation that is dimensionally
consistent.
Nevertheless, it is not valid.
Being dimensionally consistent is a necessary, but insufficent, condition
for establishing the validity of a relation.
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 12:30:44 PM |
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Don1 wrote:
Don1 wrote:
The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displacement (s/t) that it causes is a
constant: Equal to the body's weight (w), divided by the rate (g/2) at
which it will free fall at the location of the weight-scale on which it
is weighed.
This can be written mathematically as m=ft^2/s, and is equal to 2w/g;
so that for m = 1slug we get:
1 slug=1 lbf sec^2/ft=2w/g; which can be reduced to 1 slug=1 lbf
sec^2/foot.
This equation is dimensionally consistent, in that it can be written
forwards, or backwards; without changing its value.
Don
For m = 1 gram we get: 1 gram=1 dyne sec^2/cm=2w/g; where 2w/g is equal
to two times 981 dynes divided by 981 cm per sec^2.
For m = 1 kilohram we get: 1 kilogram=1 newton sec^2/m=2w/g; where 2w/g
is equal to two times 9.81 newtons divided by 9.81 m per sec^2.
These equations are dimensionally consistent, in that they can be
written forwards, or backwards; without changing their value.
In all cases they will be equal to ft^2/s=2w/g; = 2w/g=ft^2/s!
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| User: "" |
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| Title: Re: Dimensional consistency |
11 Nov 2005 08:10:56 PM |
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Don1 wrote:
The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displacement (s/t) that it causes is a
constant: Equal to the body's weight (w), divided by the rate (g/2) at
which it will free fall at the location of the weight-scale on which it
is weighed.
This can be written mathematically as m=ft^2/s, and is equal to 2w/g;
so that for m = 1slug we get:
1 slug=1 lbf sec^2/ft=2w/g; which can be reduced to 1 slug=1 lbf
sec^2/foot.
This equation is dimensionally consistent, in that it can be written
forwards, or backwards; without changing its value.
Don
xxein: I think you should repeat your third grade education.
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| User: "Bob Cain" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 03:48:19 AM |
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Don1 wrote:
This equation is dimensionally consistent, in that it can be written
forwards, or backwards; without changing its value.
Please illustrate this principle with an inconsistent equation that does
change its value when written backwards.
Thanks,
Bob
--
"Things should be described as simply as possible, but no simpler."
A. Einstein
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| User: "Eric Gisse" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 07:58:08 PM |
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Don1 wrote:
[snip]
Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
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| User: "odin" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 08:29:13 PM |
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Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
Either Don1 is a liar about his engineering days, or he has suffered some
mental problems since those days. He is beyond hope in either case.
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| User: "" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 08:36:40 PM |
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Either Don1 is a liar about his engineering days, or he has suffered
some mental problems since those days.
**************************
"Fantastic insight into the true nature of Reality is isomorphic to
insanity, but sleep usually clears it up, unless one is schitzo."
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 08:50:13 PM |
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wrote:
Either Don1 is a liar about his engineering days, or he has suffered
some mental problems since those days.
**************************
"Fantastic insight into the true nature of Reality is isomorphic to
insanity, but sleep usually clears it up, unless one is schitzo."
Is _that_ your problem?
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 08:56:04 PM |
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odin wrote:
Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
Either Don1 is a liar about his engineering days, or he has suffered some
mental problems since those days. He is beyond hope in either case.
Maybe it's you who are beyond hope!
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
12 Nov 2005 08:47:53 PM |
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Eric Gisse wrote:
Don1 wrote:
[snip]
Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
You just won't quit will you. Somebody thought I was an engineer, and
paid me well; for twenty years.
Did it ever occur to you that algebra isn't as useful for mechanical
apptitude as you think; that not everyone uses it very much?
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| User: "Steve Ralph" |
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| Title: Re: Dimensional consistency |
13 Nov 2005 07:08:33 AM |
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"Don1" <dcshead@charter.net> wrote in message
news:1131850073.054502.154780@z14g2000cwz.googlegroups.com...
Eric Gisse wrote:
Don1 wrote:
[snip]
Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
You just won't quit will you. Somebody thought I was an engineer, and
paid me well; for twenty years.
Did it ever occur to you that algebra isn't as useful for mechanical
apptitude as you think; that not everyone uses it very much?
Maybe, but why are you so proud of the fact that you simply don't
understand even the basics?
Also, you will not get very far with physics without algebra - as you
so succinctly and repeatedly demonstrate.
sr
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
13 Nov 2005 04:17:28 PM |
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Steve Ralph wrote:
"Don1" <dcshead@charter.net> wrote in message
news:1131850073.054502.154780@z14g2000cwz.googlegroups.com...
Eric Gisse wrote:
Don1 wrote:
[snip]
Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
You just won't quit will you. Somebody thought I was an engineer, and
paid me well; for twenty years.
Did it ever occur to you that algebra isn't as useful for mechanical
apptitude as you think; that not everyone uses it very much?
Maybe, but why are you so proud of the fact that you simply don't
understand even the basics?
I'm not proud of it; simply reached a point where I understood enough
to do my job; quite well too, thank you.
Also, you will not get very far with physics without algebra - as you
so succinctly and repeatedly demonstrate.
Apparently I know enough algebra, and succinctly and repeatedly
demonstrated that I did; for twenty years.
What is this thing with you and algrbra? Is it what you teach, or just
all you know?
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| User: "Steve Ralph" |
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| Title: Re: Dimensional consistency |
14 Nov 2005 02:46:07 AM |
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"Don1" <dcshead@charter.net> wrote in message
news:1131920248.815373.86170@z14g2000cwz.googlegroups.com...
Steve Ralph wrote:
"Don1" <dcshead@charter.net> wrote in message
news:1131850073.054502.154780@z14g2000cwz.googlegroups.com...
Eric Gisse wrote:
Don1 wrote:
[snip]
Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
You just won't quit will you. Somebody thought I was an engineer, and
paid me well; for twenty years.
Did it ever occur to you that algebra isn't as useful for mechanical
apptitude as you think; that not everyone uses it very much?
Maybe, but why are you so proud of the fact that you simply don't
understand even the basics?
I'm not proud of it; simply reached a point where I understood enough
to do my job; quite well too, thank you.
Also, you will not get very far with physics without algebra - as you
so succinctly and repeatedly demonstrate.
Apparently I know enough algebra, and succinctly and repeatedly
demonstrated that I did; for twenty years.
What is this thing with you and algrbra? Is it what you teach, or just
all you know?
Don, you dimwit, I work in a physics research lab. Put it like this,
you wouldn't become a lorry driver if you didn't know how to drive!
sr
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| User: "Don1" |
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| Title: Re: Dimensional consistency |
14 Nov 2005 07:37:15 AM |
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Steve Ralph wrote:
"Don1" <dcshead@charter.net> wrote in message
news:1131920248.815373.86170@z14g2000cwz.googlegroups.com...
Steve Ralph wrote:
"Don1" <dcshead@charter.net> wrote in message
news:1131850073.054502.154780@z14g2000cwz.googlegroups.com...
Eric Gisse wrote:
Don1 wrote:
[snip]
Holy ***** how could you have possibly been an engineer when algebra
gives you so much trouble?
You just won't quit will you. Somebody thought I was an engineer, and
paid me well; for twenty years.
Did it ever occur to you that algebra isn't as useful for mechanical
apptitude as you think; that not everyone uses it very much?
Maybe, but why are you so proud of the fact that you simply don't
understand even the basics?
I'm not proud of it; simply reached a point where I understood enough
to do my job; quite well too, thank you.
Also, you will not get very far with physics without algebra - as you
so succinctly and repeatedly demonstrate.
Apparently I know enough algebra, and succinctly and repeatedly
demonstrated that I did; for twenty years.
What is this thing with you and algrbra? Is it what you teach, or just
all you know?
Don, you dimwit, I work in a physics research lab. Put it like this,
you wouldn't become a lorry driver if you didn't know how to drive!
And despite the fact that you work in a research lab, it would take all
of five minutes to become a lorry driver.
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| User: "" |
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| Title: Re: Dimensional consistency |
11 Nov 2005 08:19:00 PM |
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The ratio of the net impulse (ft) exerted on, and/or by a body of
matter, divided by the rate of displace......
*************
Fascinating. Could you please release that for distribution, or is it
embargoed?????
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