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MICHAEL SHORT: So,
today we're going

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to get into the most politically
and emotionally fraught

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00:00:26,420 --> 00:00:30,410
topic of this course
for stuff on chemical

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and biological
effects of radiation.

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00:00:32,340 --> 00:00:35,090
Now that you know the units
of dose, background dose,

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we're going to talk about
what ionizing radiation does

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in the body, to cells,
to other things,

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and we're going to get into a
lot of the feelings associated

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with it.

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00:00:44,060 --> 00:00:46,460
And by the end of this
lecture, or Thursday,

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I'm going to teach you
guys how to smell bullshit.

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Because we're going to go
through one of millions

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of internet articles about
things that cause cancer,

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00:00:54,890 --> 00:00:56,570
that don't cause cancer.

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00:00:56,570 --> 00:00:59,570
In this case, it's going to
be radiation from cell phones.

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00:00:59,570 --> 00:01:02,180
So I'm going to try to
reserve at least 10 minutes

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00:01:02,180 --> 00:01:05,690
at the end of this class for us
to go through a bunch of quote,

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unquote, studies and
misinterpretations

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00:01:09,050 --> 00:01:10,100
of those conclusions.

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And I was going to pick my
favorite of the 44 studies,

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and looking through them all,
my favorite are all of them.

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AUDIENCE: [LAUGHTER]

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MICHAEL SHORT: So we'll see
how many we can get through.

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But let's get into
the science first,

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so you can understand a
bit about what goes on

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00:01:22,640 --> 00:01:24,680
with ionizing radiation.

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00:01:24,680 --> 00:01:27,650
Like radiation
damage in materials,

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00:01:27,650 --> 00:01:29,660
radiation damage and
biological systems

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is an extremely
multi-time-scale process.

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00:01:32,960 --> 00:01:36,200
Everything from the physical
stage, or the ballistic stage,

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00:01:36,200 --> 00:01:39,020
of radiation damage
to biological tissues

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00:01:39,020 --> 00:01:41,840
acting on femtoseconds,
where this

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00:01:41,840 --> 00:01:45,290
is just the physical knocking
about atoms and creation

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00:01:45,290 --> 00:01:49,220
of free radicals, these ionized
species, which in metals you

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00:01:49,220 --> 00:01:51,950
wouldn't care about, in
biological organisms you

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00:01:51,950 --> 00:01:54,260
do because then they
undergo chemical

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00:01:54,260 --> 00:01:56,690
reactions from the
initial movement

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00:01:56,690 --> 00:02:00,470
and creation of other
strange radiolytic species

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00:02:00,470 --> 00:02:03,080
and the diffusion and
reaction of those things,

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00:02:03,080 --> 00:02:05,120
which starts and
finishes in about a

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00:02:05,120 --> 00:02:08,810
microsecond, before most of
these things are neutralized.

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00:02:08,810 --> 00:02:12,260
And then, later on, the buildup
of those oxidative byproducts

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00:02:12,260 --> 00:02:15,710
of these chemical reactions
undergo the biological stages

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of radiation damage.

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All of the free radicals
with biological molecules

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have reacted within
a millisecond.

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So radiation goes in, a
millisecond later the damage

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is done.

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00:02:25,880 --> 00:02:28,700
Then you start to affect,
let's say, cell division.

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It takes, on average, minutes
for a rapidly dividing cell

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to undergo a division.

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That's when the
effects would first be

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manifest from a DNA mutation.

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But then it'd take
things like weeks,

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or years for these
sorts of things

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to manifest in a
health-related aspect.

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So, the division of one
cancerous cell into two

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won't change the way
your body functions,

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but the doubling in size of a
tumor that blocks other tissue

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absolutely would.

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And so, it all starts in
this sub-femtosecond regime,

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when most of you-- well,
for this entire year,

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we've been approximating
humans as water.

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We're going to continue
to do so for the purposes

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of these biological effects.

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So, let's say you, a
giant sack of water,

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gets irradiated by a gamma ray.

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And that gamma ray undergoes
Compton scattering.

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Which, now you know how to tell
what the energy of the Compton

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electron would be.

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We never talked about what
happens with the molecule where

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it came from.

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That molecule remains ionized.

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And since you're not especially
electrically conductive,

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they're not neutralized
immediately.

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And you can be left over
with either a free radical

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or an electron in
an excited state.

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And then what happens
next is the whole basis

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of radiation damage to
biological organisms.

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These free radicals can
then encounter other ones,

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and let's say an H2O+, can
very quickly find a neighboring

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water molecule, which they're
almost touching and form OH

90
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and H3O.

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This is better known as H+, and
that OH is a kind of unstable

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molecule.

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And these excited electrons
here can also become these

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H2O+'s, leading to this cascade
of what we call radiolysis

95
00:04:07,460 --> 00:04:08,850
reactions.

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00:04:08,850 --> 00:04:10,310
There's a few of
them listed here,

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things like an OH plus
an aqueous electron,

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which could come from anywhere,
like Compton scattering,

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00:04:16,760 --> 00:04:20,060
like any other biological
process that frees an electron,

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00:04:20,060 --> 00:04:22,010
can make another OH-.

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So you can locally change
the pH inside the cell

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that you happen
to be irradiating.

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Or, let's say any of
these oxidative byproducts

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could encounter DNA.

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Rip off or add an electron to
one of the guanine, thymine,

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00:04:36,700 --> 00:04:39,380
or other two or three
bases in DNA or RNA,

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00:04:39,380 --> 00:04:42,840
then you've changed the
genetic code of the cell.

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In the progression of these
radiologists byproducts,

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like I mentioned, whether you
go by excitation or ionization,

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00:04:49,020 --> 00:04:52,860
then you start to build up
these six species-- these five

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00:04:52,860 --> 00:04:55,230
species tend to be--
or these six ones

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00:04:55,230 --> 00:04:58,290
tend to be the ending
byproducts of a whole host

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00:04:58,290 --> 00:04:59,502
of radiolysis reactions.

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00:04:59,502 --> 00:05:00,960
And don't worry,
you're never going

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00:05:00,960 --> 00:05:02,730
to have to memorize
all the radiolysis

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00:05:02,730 --> 00:05:06,690
reactions because the mechanism
map is fairly complicated

117
00:05:06,690 --> 00:05:09,037
and there are multiple
routes to creating each one.

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00:05:09,037 --> 00:05:10,620
But the ones that
are highlighted here

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00:05:10,620 --> 00:05:12,390
in these squares,
are the ones that

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00:05:12,390 --> 00:05:16,200
end up building up in your
body, things like peroxide.

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00:05:16,200 --> 00:05:19,110
Has anyone ever put
peroxide on a wound before?

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00:05:19,110 --> 00:05:20,020
What happens?

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00:05:20,020 --> 00:05:20,520
Yell it out.

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AUDIENCE: It bubbles up.

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MICHAEL SHORT: Bubbles up.

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00:05:22,380 --> 00:05:24,390
What happens when you
form peroxide in your body

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00:05:24,390 --> 00:05:25,552
from radiation?

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00:05:25,552 --> 00:05:26,790
AUDIENCE: It bubbles up.

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00:05:26,790 --> 00:05:28,665
MICHAEL SHORT: Well,
luckily it doesn't quite

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00:05:28,665 --> 00:05:30,270
bubble up on the
macro scale level,

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00:05:30,270 --> 00:05:33,390
but it is a vigorous oxidizer.

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00:05:33,390 --> 00:05:37,920
90% H2O2 is used as rocket
fuel, as the oxidizing species

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00:05:37,920 --> 00:05:39,000
in rocket fuel.

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00:05:39,000 --> 00:05:42,160
You don't make 90% H2O2
from getting irradiated,

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but every molecule counts.

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Things like O2, you're
shifting the amount

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00:05:46,290 --> 00:05:48,120
of oxygen in the cells.

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00:05:48,120 --> 00:05:50,430
And then there's things like
these superoxide radicals,

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00:05:50,430 --> 00:05:56,130
or H2O-, H2O+, or all these
other things that are available

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00:05:56,130 --> 00:05:58,920
to rip off or add an electron
to something else that normally

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00:05:58,920 --> 00:06:00,210
wouldn't have it.

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00:06:00,210 --> 00:06:02,880
And the list of these
potential reactions,

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00:06:02,880 --> 00:06:05,250
as well as their equilibrium
constants and activation

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00:06:05,250 --> 00:06:07,060
energy, is huge.

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00:06:07,060 --> 00:06:09,350
Here's half of it.

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00:06:09,350 --> 00:06:11,030
Notice a lot of
these equilibrium

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00:06:11,030 --> 00:06:13,610
constants shift really
strongly one way or the other.

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So, just because these
molecules are made,

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doesn't mean that
all of them end up

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00:06:17,930 --> 00:06:19,940
staying and doing damage.

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But unless these rate constants
are either 0 or infinity,

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00:06:25,910 --> 00:06:29,610
there's going to be some dynamic
equilibrium of these reactions.

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So, once in a while, some
of these free radicals

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will escape the cloud of
chemical change and charge

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and get to something else.

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00:06:38,180 --> 00:06:40,340
Here's the other half
of the equation set.

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00:06:40,340 --> 00:06:43,010
And it's under debate just
how many of these reactions

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there actually are.

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Like, how often would O2-
radicals combine with water,

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which you can see is not
quite set in the reaction,

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00:06:51,290 --> 00:06:57,740
to form [? HO2 - NO2 NH+ ?] Kind
of a strange little reaction

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00:06:57,740 --> 00:06:58,460
right there.

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00:06:58,460 --> 00:06:59,810
Actually, a lot of
them are quite strange.

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00:06:59,810 --> 00:07:01,518
You don't usually
think of them happening

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because these are very transient
reactions, whose byproducts

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do build up.

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And that's the chemical
basis for radiation damage

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00:07:09,530 --> 00:07:11,360
to biological tissues.

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00:07:11,360 --> 00:07:14,720
Now, once those
chemical products form,

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they have to move or diffuse.

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00:07:17,150 --> 00:07:20,570
So you can actually calculate
or get diffusion coefficients

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00:07:20,570 --> 00:07:23,330
for some of these
oxidizing species,

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00:07:23,330 --> 00:07:25,490
as well as compute
an average radius

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00:07:25,490 --> 00:07:28,620
that they'll remove before
undergoing a reaction.

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So this is part of
the basis for why

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00:07:30,830 --> 00:07:34,490
alpha radiation is a lot more
damaging than gamma radiation.

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00:07:34,490 --> 00:07:37,820
Chances are, if you incorporate
an alpha emitter into the cell,

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00:07:37,820 --> 00:07:39,680
it does a whole bunch of damage.

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00:07:39,680 --> 00:07:43,490
That damage consists of these
oxidative chemical species,

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00:07:43,490 --> 00:07:47,420
that, if they're that far away
from neighboring atoms that

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00:07:47,420 --> 00:07:50,360
happen to be in DNA, they
might do some damage.

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Whereas, isolated Compton
scatters and photoelectric

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00:07:53,450 --> 00:07:57,810
exhortations from gamma
radiation, not so much.

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00:07:57,810 --> 00:08:00,140
Chances are you hit random
water in the cell that

185
00:08:00,140 --> 00:08:06,350
isn't quite close to anything,
fragile, and not much happens.

186
00:08:06,350 --> 00:08:08,820
But you can also see this by
looking at charged particle

187
00:08:08,820 --> 00:08:09,320
tracks.

188
00:08:09,320 --> 00:08:12,110
These things can actually
be experimentally measured.

189
00:08:12,110 --> 00:08:16,080
By firing electrons into gel
or film or something like that,

190
00:08:16,080 --> 00:08:18,860
you can actually see
tracks of ionization

191
00:08:18,860 --> 00:08:20,580
and watch them as
a function of time.

192
00:08:20,580 --> 00:08:23,300
In this case, it's a simulation
of a charged particle

193
00:08:23,300 --> 00:08:25,820
track at different timescales.

194
00:08:25,820 --> 00:08:27,620
So, right here, this
10 to the minus 12

195
00:08:27,620 --> 00:08:30,080
for the time in
seconds, tells you

196
00:08:30,080 --> 00:08:33,110
where these radiolysis
products are.

197
00:08:33,110 --> 00:08:37,549
And the N number, here, tells
you how many of those remain.

198
00:08:37,549 --> 00:08:40,640
So after a picosecond,
you can pretty much just

199
00:08:40,640 --> 00:08:44,420
trace out the path that the
electron took, starts off right

200
00:08:44,420 --> 00:08:46,390
here.

201
00:08:46,390 --> 00:08:48,550
What do you guys notice
about the density

202
00:08:48,550 --> 00:08:52,700
of the charged particle track
as it moves from the source

203
00:08:52,700 --> 00:08:55,560
to the end?

204
00:08:55,560 --> 00:08:57,310
AUDIENCE: It's much
more dense at the end.

205
00:08:57,310 --> 00:08:59,268
MICHAEL SHORT: It's much
more dense at the end.

206
00:08:59,268 --> 00:09:00,982
And why do you think that is?

207
00:09:00,982 --> 00:09:02,400
AUDIENCE: Stopping power.

208
00:09:02,400 --> 00:09:03,150
MICHAEL SHORT: OK.

209
00:09:03,150 --> 00:09:04,020
More than just-- yeah.

210
00:09:04,020 --> 00:09:05,937
Stopping power, yes, but
fill in the beginning

211
00:09:05,937 --> 00:09:07,170
and end of that sentence.

212
00:09:07,170 --> 00:09:07,980
Chris, do you have your hand up?

213
00:09:07,980 --> 00:09:09,920
AUDIENCE: [? It's all good. ?]
So, it's a charged particle,

214
00:09:09,920 --> 00:09:12,345
so it drops off most of it's
energy where it has the least

215
00:09:12,345 --> 00:09:14,903
amount of energy, so it does
the most damage [INAUDIBLE]..

216
00:09:14,903 --> 00:09:16,070
MICHAEL SHORT: That's right.

217
00:09:16,070 --> 00:09:17,870
So, you're actually
visualizing the change

218
00:09:17,870 --> 00:09:21,050
in stopping power as a function
of charged particle energy.

219
00:09:21,050 --> 00:09:23,750
It comes in, has a
very high energy.

220
00:09:23,750 --> 00:09:26,728
And it might knock a little
radiation damage cascade

221
00:09:26,728 --> 00:09:28,520
by hitting another
electron, which can have

222
00:09:28,520 --> 00:09:30,490
its own shower of ionization.

223
00:09:30,490 --> 00:09:33,470
And then it moves while doing
nothing, in this straight line,

224
00:09:33,470 --> 00:09:34,850
until it hits another one.

225
00:09:34,850 --> 00:09:36,650
And notice right
at the end, that's

226
00:09:36,650 --> 00:09:40,130
where the densest amount of
damage is done because that's

227
00:09:40,130 --> 00:09:42,020
where the stopping
power is the highest.

228
00:09:42,020 --> 00:09:44,060
It's also where the
energy is the lowest.

229
00:09:44,060 --> 00:09:46,700
So, this is where the worlds
of and physics collide.

230
00:09:46,700 --> 00:09:50,000
You can actually visualize
stopping power, like actually

231
00:09:50,000 --> 00:09:53,120
visually in gel or on
film or on a computer

232
00:09:53,120 --> 00:09:55,490
by watching these
charged particle tracks.

233
00:09:55,490 --> 00:09:57,110
And after 10 to the
minus 12 seconds,

234
00:09:57,110 --> 00:09:58,760
all the ballistics are over.

235
00:09:58,760 --> 00:10:01,680
Then you end up with
diffusion and reaction.

236
00:10:01,680 --> 00:10:04,640
So, it's going to be a balance
between these charged particles

237
00:10:04,640 --> 00:10:07,640
moving away from each other
and finding something else,

238
00:10:07,640 --> 00:10:10,550
or finding each other
and re-combining.

239
00:10:10,550 --> 00:10:13,190
And that's why, as you
go up in timescale,

240
00:10:13,190 --> 00:10:16,280
the particle tracks get
more and more diffuse

241
00:10:16,280 --> 00:10:19,040
and the number of these
remaining free radicals

242
00:10:19,040 --> 00:10:23,402
goes down until you level
out at about a microsecond,

243
00:10:23,402 --> 00:10:24,860
when all of the
different particles

244
00:10:24,860 --> 00:10:26,402
are so spread out
that there are none

245
00:10:26,402 --> 00:10:28,850
touching each other anymore.

246
00:10:28,850 --> 00:10:31,615
To refresh your memory a
bit from a few seconds ago,

247
00:10:31,615 --> 00:10:32,990
take a look at
some of the charge

248
00:10:32,990 --> 00:10:36,110
states of these
oxidative byproducts.

249
00:10:36,110 --> 00:10:41,190
Some of them plus, some of them
minus, sum of them excited,

250
00:10:41,190 --> 00:10:42,120
all over the place.

251
00:10:42,120 --> 00:10:44,220
So they can react
with each other, which

252
00:10:44,220 --> 00:10:46,710
is something you'd want
to encourage so that they

253
00:10:46,710 --> 00:10:48,750
don't go and find
something else, causing

254
00:10:48,750 --> 00:10:51,370
biological damage.

255
00:10:51,370 --> 00:10:55,090
There's a question on last
year's OCW problem set,

256
00:10:55,090 --> 00:10:57,310
that I'm not giving
you for this one, which

257
00:10:57,310 --> 00:10:59,230
is, calculate the
radiation resistance you

258
00:10:59,230 --> 00:11:02,365
would get by getting
cryogenically frozen.

259
00:11:02,365 --> 00:11:03,740
So here's a question
that I don't

260
00:11:03,740 --> 00:11:06,260
think a lot of cryogenicists
ask themselves,

261
00:11:06,260 --> 00:11:08,750
if you want to preserve
a human for 10,000 years

262
00:11:08,750 --> 00:11:11,150
and wake them up later,
how much radiation damage

263
00:11:11,150 --> 00:11:12,025
are you going to get?

264
00:11:14,267 --> 00:11:15,850
Ever think there's
a cryogenicist that

265
00:11:15,850 --> 00:11:17,370
ask themselves that question?

266
00:11:17,370 --> 00:11:19,110
I don't actually know.

267
00:11:19,110 --> 00:11:21,068
But it's not a question
I've ever heard before,

268
00:11:21,068 --> 00:11:22,985
which is why I made it
a problem set question.

269
00:11:22,985 --> 00:11:24,855
Because I know the
answer is not out there.

270
00:11:24,855 --> 00:11:25,730
I looked for a while.

271
00:11:29,637 --> 00:11:31,470
Let's switch particles
for a second and look

272
00:11:31,470 --> 00:11:34,080
at the charged particle
tracks from a proton.

273
00:11:34,080 --> 00:11:36,733
What differences do you
see between the proton

274
00:11:36,733 --> 00:11:38,400
and the electron
charged particle track?

275
00:11:42,110 --> 00:11:44,920
So, proton, electron.

276
00:11:44,920 --> 00:11:46,930
Proton, electron.

277
00:11:46,930 --> 00:11:48,630
AUDIENCE: There's no curve.

278
00:11:48,630 --> 00:11:49,220
MICHAEL SHORT: There's what?

279
00:11:49,220 --> 00:11:49,560
AUDIENCE: There's curve.

280
00:11:49,560 --> 00:11:49,900
It's straight.

281
00:11:49,900 --> 00:11:51,067
MICHAEL SHORT: Its straight.

282
00:11:51,067 --> 00:11:54,320
Why do you think it's straight?

283
00:11:54,320 --> 00:11:56,416
Why does anyone
think it's straight?

284
00:11:56,416 --> 00:11:57,458
AUDIENCE: They're bigger.

285
00:11:57,458 --> 00:11:59,870
MICHAEL SHORT: They are
bigger, more massive.

286
00:11:59,870 --> 00:12:03,410
So the same deflection, the
same transfer of momentum,

287
00:12:03,410 --> 00:12:08,570
to an electron using our beloved
hollow cylinder approximation

288
00:12:08,570 --> 00:12:13,490
thing, causes less of a change
in direction for a proton

289
00:12:13,490 --> 00:12:14,930
as it does an electron.

290
00:12:14,930 --> 00:12:16,620
The forces are the same.

291
00:12:16,620 --> 00:12:19,670
They're both just a plus
or minus 1 hitting a plus

292
00:12:19,670 --> 00:12:21,200
or minus 1 charge.

293
00:12:21,200 --> 00:12:24,250
But the mass is quite
different on the proton,

294
00:12:24,250 --> 00:12:25,750
so it doesn't get
deflected as much,

295
00:12:25,750 --> 00:12:27,125
which is why the
charged particle

296
00:12:27,125 --> 00:12:29,600
tracks are so straight.

297
00:12:29,600 --> 00:12:32,210
Now, what are these things here?

298
00:12:32,210 --> 00:12:34,340
What are those offshoots?

299
00:12:34,340 --> 00:12:35,745
AUDIENCE: [INAUDIBLE]

300
00:12:35,745 --> 00:12:38,120
MICHAEL SHORT: They're secondary
charged particle tracks.

301
00:12:38,120 --> 00:12:40,410
So, let's say a proton
hits an electron,

302
00:12:40,410 --> 00:12:44,030
that electron can have any
amount of energy, probably

303
00:12:44,030 --> 00:12:45,915
going to be lower
than the proton did.

304
00:12:45,915 --> 00:12:47,790
And it's going to cause
its own little damage

305
00:12:47,790 --> 00:12:49,380
cascade right there.

306
00:12:49,380 --> 00:12:53,670
And, just like before, you
can track the number of these

307
00:12:53,670 --> 00:12:58,320
charged particle trucks moving
from 5000 to about 1000,

308
00:12:58,320 --> 00:13:00,960
between, let's
say, 10 picoseconds

309
00:13:00,960 --> 00:13:03,120
and a little less
than a microsecond.

310
00:13:03,120 --> 00:13:06,000
And once these charged particles
have spread out or diffused

311
00:13:06,000 --> 00:13:09,940
away, chances are recombination
has gone down quite a bit

312
00:13:09,940 --> 00:13:11,970
and they're going to go
react with other things.

313
00:13:11,970 --> 00:13:14,690
And this is a perfect analogy
to radiation damage in metal.

314
00:13:14,690 --> 00:13:17,690
So, radiation damage in biology
is like radiation damage

315
00:13:17,690 --> 00:13:19,170
in material science.

316
00:13:19,170 --> 00:13:21,990
You have this initial
cluster of damage,

317
00:13:21,990 --> 00:13:25,260
in materials it's usually
vacancies or intestinals,

318
00:13:25,260 --> 00:13:27,880
in biology it's
charged particles.

319
00:13:27,880 --> 00:13:29,730
But when they're
in a dense cascade

320
00:13:29,730 --> 00:13:31,355
they can recombine
with each other.

321
00:13:31,355 --> 00:13:32,730
And the ones that
miss each other

322
00:13:32,730 --> 00:13:35,940
go off to find either other
defects in the material

323
00:13:35,940 --> 00:13:39,630
or other atoms in your cells.

324
00:13:39,630 --> 00:13:41,740
It's a very fitting analogy.

325
00:13:41,740 --> 00:13:42,240
Yeah?

326
00:13:42,240 --> 00:13:46,270
AUDIENCE: How come we don't
see like a denser [INAUDIBLE]

327
00:13:46,270 --> 00:13:48,630
to the proton
[INAUDIBLE] electrons?

328
00:13:48,630 --> 00:13:50,220
MICHAEL SHORT: Let's see.

329
00:13:50,220 --> 00:13:53,190
I don't know if we see the whole
charged particle track here.

330
00:13:53,190 --> 00:13:55,440
You're right, it doesn't
look like the density changes

331
00:13:55,440 --> 00:13:55,940
very much.

332
00:13:55,940 --> 00:13:58,110
You can't even really
tell where the source is.

333
00:13:58,110 --> 00:14:00,490
We may not be looking
at the whole thing.

334
00:14:00,490 --> 00:14:01,490
Here's another question.

335
00:14:01,490 --> 00:14:04,060
So, it's a 2 MeV proton.

336
00:14:04,060 --> 00:14:06,730
That scale bar is 0.1 microns.

337
00:14:06,730 --> 00:14:10,600
Let's do a quick simulation
to verify this idea.

338
00:14:10,600 --> 00:14:13,030
Luckily we have the
tools to do this,

339
00:14:13,030 --> 00:14:15,150
soon as I clone my screen.

340
00:14:15,150 --> 00:14:18,670
Let's use SRIM and find out what
is the range of 2 MeV protons

341
00:14:18,670 --> 00:14:19,450
in water.

342
00:14:19,450 --> 00:14:22,270
And if it's more than about a
micron, which is what's shown--

343
00:14:22,270 --> 00:14:23,920
well, let's say,
that's 2 microns.

344
00:14:23,920 --> 00:14:26,253
If it's more than 2 microns,
what's shown on the screen,

345
00:14:26,253 --> 00:14:29,530
it means we're not
seeing the whole track.

346
00:14:29,530 --> 00:14:31,690
SRIM.

347
00:14:31,690 --> 00:14:33,450
Good, you can see it.

348
00:14:33,450 --> 00:14:38,580
So let's say, hydrogen at 2 MeV,
going into something consisting

349
00:14:38,580 --> 00:14:44,700
of H and O in a
ratio of 2:1, make

350
00:14:44,700 --> 00:14:49,140
sure its density is correct
for room temperature water,

351
00:14:49,140 --> 00:14:51,700
and let's look at a
range of 25 microns,

352
00:14:51,700 --> 00:14:53,450
because I kind of
already know the answer.

353
00:14:53,450 --> 00:14:55,770
AUDIENCE: [LAUGHTER]

354
00:14:55,770 --> 00:14:57,690
MICHAEL SHORT: Much
more than 25 microns.

355
00:14:57,690 --> 00:15:00,340
So, our initial
assertion was correct.

356
00:15:00,340 --> 00:15:03,331
Let's actually find
out what the range is.

357
00:15:03,331 --> 00:15:06,220
Let's put 40 microns.

358
00:15:06,220 --> 00:15:08,620
Whew, it's a little
more than I thought.

359
00:15:08,620 --> 00:15:14,818
Protons in water, at just 2 MeV.

360
00:15:14,818 --> 00:15:18,910
Let's fly tons of them.

361
00:15:18,910 --> 00:15:21,140
Wait til we get about 1,000.

362
00:15:21,140 --> 00:15:22,640
Look at the range.

363
00:15:22,640 --> 00:15:24,470
Make it bigger so
you can read it.

364
00:15:24,470 --> 00:15:26,030
75 microns.

365
00:15:26,030 --> 00:15:30,708
75.5 micron range.

366
00:15:30,708 --> 00:15:31,250
There you go.

367
00:15:35,790 --> 00:15:37,302
Let's go back to the big one.

368
00:15:37,302 --> 00:15:38,010
So, there you go.

369
00:15:38,010 --> 00:15:41,160
If this scale bar is 0.1
microns, you're looking about 2

370
00:15:41,160 --> 00:15:43,650
of the 75 microns of
charged particle track.

371
00:15:43,650 --> 00:15:45,900
Interesting, no one picked
up that question last year,

372
00:15:45,900 --> 00:15:47,100
but I'm glad you did.

373
00:15:47,100 --> 00:15:50,495
I'm glad we were able to
show you where it comes from.

374
00:15:50,495 --> 00:15:51,870
So this will look
quite different

375
00:15:51,870 --> 00:15:54,970
if you're looking at the end
of the charged particle track.

376
00:15:54,970 --> 00:15:55,470
Cool.

377
00:15:55,470 --> 00:15:58,260
Good question.

378
00:15:58,260 --> 00:15:59,880
To look really,
really close up, you

379
00:15:59,880 --> 00:16:01,980
see a lot more of
this branching again.

380
00:16:01,980 --> 00:16:04,740
So whenever a proton strikes,
let's say another atom

381
00:16:04,740 --> 00:16:07,950
or an electron, you get your
own little dense damage cascade.

382
00:16:07,950 --> 00:16:10,000
And look at that, not
much until the very end

383
00:16:10,000 --> 00:16:14,620
when you get this cloud of
damage popping off at the end.

384
00:16:14,620 --> 00:16:17,320
So, yet more examples of the
physics that you've learned

385
00:16:17,320 --> 00:16:19,295
popping up in
biological systems.

386
00:16:19,295 --> 00:16:20,920
The difference is
it's water not metal,

387
00:16:20,920 --> 00:16:22,600
but otherwise
everything's the same.

388
00:16:25,690 --> 00:16:27,743
And then we get to
what's called G-values.

389
00:16:27,743 --> 00:16:29,410
I don't know why it's
called G, but I'll

390
00:16:29,410 --> 00:16:31,210
tell you what they mean.

391
00:16:31,210 --> 00:16:36,640
It's the number of each species,
per 100 MeV, found later,

392
00:16:36,640 --> 00:16:40,430
at let's say, 0.28 microseconds,
or typically 1 microsecond,

393
00:16:40,430 --> 00:16:42,820
for different particles
of various energies.

394
00:16:42,820 --> 00:16:46,240
These are relative
effectiveness' of these

395
00:16:46,240 --> 00:16:49,600
particles at different energies
to leave oxidative byproducts

396
00:16:49,600 --> 00:16:50,410
by.

397
00:16:50,410 --> 00:16:53,818
So there's a few things that are
wrapped up into these G-values.

398
00:16:53,818 --> 00:16:55,360
So, notice that, in
this case, here's

399
00:16:55,360 --> 00:16:57,680
a G-value for electron energy.

400
00:16:57,680 --> 00:16:59,590
At different
energies, you'll have

401
00:16:59,590 --> 00:17:05,710
different amounts of OH, H3O
in such, per 100 eV of energy.

402
00:17:05,710 --> 00:17:07,900
So the unit of
G-values here, it's

403
00:17:07,900 --> 00:17:12,109
like number of chemical
species per 100 eV of energy.

404
00:17:12,109 --> 00:17:16,010
So it's an energy normalized
measure of the effectiveness

405
00:17:16,010 --> 00:17:19,140
of radiation making chemicals.

406
00:17:19,140 --> 00:17:20,190
Does make sense to folks?

407
00:17:20,190 --> 00:17:23,536
If not, raise your hand
and I'll try to re-explain.

408
00:17:23,536 --> 00:17:24,036
OK.

409
00:17:24,036 --> 00:17:24,920
AUDIENCE: Please repeat it.

410
00:17:24,920 --> 00:17:25,712
MICHAEL SHORT: Yep.

411
00:17:25,712 --> 00:17:31,720
So a G-value, it's got units in
concentration per unit energy.

412
00:17:31,720 --> 00:17:34,200
And it's a measure
of how many chemicals

413
00:17:34,200 --> 00:17:38,920
a given particle will make
as a function of its energy.

414
00:17:38,920 --> 00:17:42,440
And these particles are the ones
that survive the recombination

415
00:17:42,440 --> 00:17:44,940
and end up diffusing
to other species.

416
00:17:44,940 --> 00:17:47,480
So, these G-values, it's
kind of like how many

417
00:17:47,480 --> 00:17:52,210
oxidative species are made that
go off and damage other things?

418
00:17:52,210 --> 00:17:54,320
Let's look at some
trends right here.

419
00:17:54,320 --> 00:17:57,540
For things like
OH, for electrons,

420
00:17:57,540 --> 00:18:00,960
what sort of patterns do
you notice in the data?

421
00:18:00,960 --> 00:18:03,480
And take a sec to parse
some of these numbers.

422
00:18:03,480 --> 00:18:06,460
Just look at the top three rows.

423
00:18:06,460 --> 00:18:07,460
What pattern do you see?

424
00:18:13,710 --> 00:18:15,740
AUDIENCE: Starts
high and then goes--

425
00:18:15,740 --> 00:18:20,170
MICHAEL SHORT: Starts high,
goes low, goes high again.

426
00:18:20,170 --> 00:18:23,007
Why do you think that is?

427
00:18:23,007 --> 00:18:24,090
Straight from the physics.

428
00:18:28,270 --> 00:18:32,780
At super low energies,
100 eV electron,

429
00:18:32,780 --> 00:18:35,360
you'll make, on
average, 1 OH radical

430
00:18:35,360 --> 00:18:37,880
for every 100 eV of energy.

431
00:18:37,880 --> 00:18:40,760
As you increase in
energy, you start

432
00:18:40,760 --> 00:18:42,282
making fewer and
fewer per unit--

433
00:18:42,282 --> 00:18:44,240
actually, that's not the
one I want to look at.

434
00:18:44,240 --> 00:18:46,560
That's a different species.

435
00:18:46,560 --> 00:18:47,742
Let's see.

436
00:18:47,742 --> 00:18:48,490
No, that is.

437
00:18:48,490 --> 00:18:48,990
OK.

438
00:18:48,990 --> 00:18:51,735
That follows the pattern
that we're looking for.

439
00:18:51,735 --> 00:18:53,360
AUDIENCE: Does the
high energy includes

440
00:18:53,360 --> 00:18:57,120
stuff that's created from
causing secondary cascades?

441
00:18:57,120 --> 00:18:58,120
MICHAEL SHORT: Oh, yeah.

442
00:18:58,120 --> 00:19:00,800
This is just total
number from everything.

443
00:19:00,800 --> 00:19:02,150
Right?

444
00:19:02,150 --> 00:19:04,610
It's just the number of each
chemical species left over

445
00:19:04,610 --> 00:19:06,350
after a microsecond.

446
00:19:06,350 --> 00:19:10,070
So what do you think could
cause this initial increase

447
00:19:10,070 --> 00:19:13,570
and then decrease
and then increase?

448
00:19:13,570 --> 00:19:15,620
AUDIENCE: Is it because
of the cross-sections

449
00:19:15,620 --> 00:19:16,650
of different particles?

450
00:19:16,650 --> 00:19:17,733
MICHAEL SHORT: Part of it.

451
00:19:17,733 --> 00:19:20,070
The cross-sections that also
go into the stopping power.

452
00:19:20,070 --> 00:19:21,153
That's part of the answer.

453
00:19:21,153 --> 00:19:23,070
So at really low
energies, you're already

454
00:19:23,070 --> 00:19:25,170
at your stopping power peak.

455
00:19:25,170 --> 00:19:27,720
And that way, for the little
bit of energy you have,

456
00:19:27,720 --> 00:19:30,950
chances are it's going to
ionize different things.

457
00:19:30,950 --> 00:19:33,240
Then as you increase
your energy,

458
00:19:33,240 --> 00:19:35,070
you have more and
more of that range

459
00:19:35,070 --> 00:19:39,470
of the particle in the
lower stopping power region.

460
00:19:39,470 --> 00:19:42,860
So, you'll have more
of the-- let's see.

461
00:19:42,860 --> 00:19:45,950
You'll have more and
more of that particle--

462
00:19:45,950 --> 00:19:48,052
let me try and phrase
this quite well.

463
00:19:48,052 --> 00:19:50,510
Let's go back to the charged
particle tracks for electrons,

464
00:19:50,510 --> 00:19:53,520
and I'll get this--
yeah, here we go.

465
00:19:53,520 --> 00:19:56,950
So, when you're electron comes
in a really, really low energy,

466
00:19:56,950 --> 00:19:58,397
you're in that
region right there.

467
00:19:58,397 --> 00:19:59,980
Chances are you're
going to make a lot

468
00:19:59,980 --> 00:20:02,720
of those oxidative byproducts.

469
00:20:02,720 --> 00:20:05,610
And then as you go a
little higher in energy,

470
00:20:05,610 --> 00:20:07,170
you make fewer per
unit distance--

471
00:20:07,170 --> 00:20:10,270
or you make fewer
per unit energy.

472
00:20:10,270 --> 00:20:12,960
You can think of that as
the spread, right there.

473
00:20:12,960 --> 00:20:15,540
But then also, as you
go way higher in energy,

474
00:20:15,540 --> 00:20:18,133
your ability to
ionize increases.

475
00:20:18,133 --> 00:20:19,800
So you've got that
sort of 1 over E term

476
00:20:19,800 --> 00:20:22,620
in stopping power
making things worse.

477
00:20:22,620 --> 00:20:24,120
And you've got
that log of E term

478
00:20:24,120 --> 00:20:27,130
in stopping power
making things better.

479
00:20:27,130 --> 00:20:30,920
And if we go back to
the data right here,

480
00:20:30,920 --> 00:20:32,720
for those top three
or four, it tends

481
00:20:32,720 --> 00:20:35,330
to follow that
trend pretty well.

482
00:20:35,330 --> 00:20:39,020
Now what about things like H202?

483
00:20:39,020 --> 00:20:42,094
What sort of trend
do you see there?

484
00:20:42,094 --> 00:20:43,480
AUDIENCE: The opposite.

485
00:20:43,480 --> 00:20:45,320
MICHAEL SHORT: The opposite.

486
00:20:45,320 --> 00:20:46,410
So, I'll give you a hint.

487
00:20:46,410 --> 00:20:49,930
H2O2 isn't directly
made by radiolysis,

488
00:20:49,930 --> 00:20:53,860
it tends to occur by reaction
of other radiolysis products.

489
00:20:53,860 --> 00:20:55,420
So it's like a
secondary chemical,

490
00:20:55,420 --> 00:20:57,580
not a primary produced chemical.

491
00:20:57,580 --> 00:21:00,490
So, why do you think H2O2
follows the opposite trend?

492
00:21:13,178 --> 00:21:15,900
AUDIENCE: It comes from
the-- not the decay,

493
00:21:15,900 --> 00:21:18,990
but like a reaction from one of
the previous ones, that there's

494
00:21:18,990 --> 00:21:20,970
more of that first
species there, that it

495
00:21:20,970 --> 00:21:22,320
hasn't reacted to form it yet.

496
00:21:22,320 --> 00:21:24,520
But once it is
lowered, that means

497
00:21:24,520 --> 00:21:25,847
it's made more of the H2O2.

498
00:21:25,847 --> 00:21:26,680
MICHAEL SHORT: Sure.

499
00:21:26,680 --> 00:21:27,840
AUDIENCE: And then vice versa.

500
00:21:27,840 --> 00:21:28,673
MICHAEL SHORT: Yeah.

501
00:21:28,673 --> 00:21:30,980
So, to rephrase what Sarah
said, in this energy range

502
00:21:30,980 --> 00:21:35,810
right here, you're producing
this fairly dense cascade

503
00:21:35,810 --> 00:21:38,108
of oxidative byproducts.

504
00:21:38,108 --> 00:21:39,650
When those reactions
occur, they tend

505
00:21:39,650 --> 00:21:42,410
to make things like
H2O2, something that's

506
00:21:42,410 --> 00:21:45,170
not made directly from
radiolysis, but indirectly

507
00:21:45,170 --> 00:21:47,480
from recombination
of those chemicals.

508
00:21:47,480 --> 00:21:51,200
And then as you raise the energy
more and more, to like 20 keV,

509
00:21:51,200 --> 00:21:55,100
you start making those primary
products more spread out.

510
00:21:55,100 --> 00:21:56,780
They're not as
close to each other.

511
00:21:56,780 --> 00:21:58,170
They don't recombine as much.

512
00:21:58,170 --> 00:21:59,870
They don't make as much H2O2.

513
00:21:59,870 --> 00:22:02,060
They'll tend, instead, to
spread out a little more.

514
00:22:02,060 --> 00:22:03,350
So more will survive.

515
00:22:03,350 --> 00:22:06,770
More of these primary
ones will survive, and not

516
00:22:06,770 --> 00:22:10,800
react to make as many
of the secondary ones.

517
00:22:10,800 --> 00:22:14,370
So, how is that explanation
fitting with you guys?

518
00:22:14,370 --> 00:22:14,870
Cool.

519
00:22:14,870 --> 00:22:18,500
So, it's a balance between
intermediate energies.

520
00:22:18,500 --> 00:22:20,330
You make a whole lot
of primary ones, which

521
00:22:20,330 --> 00:22:23,480
are so close that they react to
make the secondary species much

522
00:22:23,480 --> 00:22:24,710
more easily.

523
00:22:24,710 --> 00:22:27,590
As you raise the energy
of the particles going in,

524
00:22:27,590 --> 00:22:30,950
you make more isolated primaries
that can't find each other,

525
00:22:30,950 --> 00:22:36,120
and they don't make as many
secondaries per unit energy.

526
00:22:36,120 --> 00:22:36,700
Yeah?

527
00:22:36,700 --> 00:22:41,510
AUDIENCE: How come for like
the 100 eV H2O2 it's less?

528
00:22:41,510 --> 00:22:45,460
Because since it's making
a lot of the initial,

529
00:22:45,460 --> 00:22:48,080
or the primary,
byproducts, wouldn't you

530
00:22:48,080 --> 00:22:50,510
expect it to also make
a lot of the secondary

531
00:22:50,510 --> 00:22:52,190
because they're
also close together?

532
00:22:52,190 --> 00:22:54,650
MICHAEL SHORT: You might,
except at very low energies,

533
00:22:54,650 --> 00:22:57,690
our idea of stopping power
isn't quite as complete.

534
00:22:57,690 --> 00:23:01,597
So, by what other processes
can electrons lose energy

535
00:23:01,597 --> 00:23:02,555
at really low energies?

536
00:23:06,750 --> 00:23:09,730
You could have a deflection
without an ionization, right?

537
00:23:09,730 --> 00:23:14,260
Just a simple-- let's say,
you could have an excitation,

538
00:23:14,260 --> 00:23:16,483
you could have just
coulomb deflection,

539
00:23:16,483 --> 00:23:17,650
you can have neutralization.

540
00:23:17,650 --> 00:23:19,942
You can have all those really,
really low energy things

541
00:23:19,942 --> 00:23:23,170
that go on, that don't end up
producing as many ionizations.

542
00:23:23,170 --> 00:23:26,230
Because you need to produce
an ionization or an excitation

543
00:23:26,230 --> 00:23:28,237
to kick off radiolysis.

544
00:23:28,237 --> 00:23:30,070
So then, when you get
high enough in energy,

545
00:23:30,070 --> 00:23:32,500
and chances are you'll
ionize rather than undergo

546
00:23:32,500 --> 00:23:36,160
one of these really low
energy inner loss mechanisms,

547
00:23:36,160 --> 00:23:38,800
then you start making
more of the primaries,

548
00:23:38,800 --> 00:23:41,800
but densely, which make
more of the secondaries.

549
00:23:41,800 --> 00:23:43,930
Then as you go even
higher in energy,

550
00:23:43,930 --> 00:23:45,753
you still make
tons of primaries,

551
00:23:45,753 --> 00:23:47,170
but since they're
spread out more,

552
00:23:47,170 --> 00:23:48,880
since the stopping
power is lower,

553
00:23:48,880 --> 00:23:50,650
they don't find
each other and they

554
00:23:50,650 --> 00:23:53,310
don't make as many secondaries.

555
00:23:53,310 --> 00:23:55,850
So, let's look at some
other numbers and trends,

556
00:23:55,850 --> 00:23:58,140
different particles.

557
00:23:58,140 --> 00:24:01,530
First of all, for protons
and for alpha particles,

558
00:24:01,530 --> 00:24:04,720
note here that the
scales are in MeV.

559
00:24:04,720 --> 00:24:09,040
Whereas, the G-Value is for
electrons in the keV range,

560
00:24:09,040 --> 00:24:14,290
and for protons in the MeV
range are pretty much the same,

561
00:24:14,290 --> 00:24:16,450
on the same order of magnitude.

562
00:24:16,450 --> 00:24:17,650
Anyone have any idea why?

563
00:24:21,997 --> 00:24:23,450
AUDIENCE: They're heavier.

564
00:24:23,450 --> 00:24:24,742
MICHAEL SHORT: They're heavier.

565
00:24:24,742 --> 00:24:27,620
And then what does that lead to
in terms of a stopping power?

566
00:24:34,578 --> 00:24:35,953
AUDIENCE: They're
easier to stop.

567
00:24:35,953 --> 00:24:37,911
MICHAEL SHORT: They're
actually harder to stop.

568
00:24:37,911 --> 00:24:40,440
If they're heavier, than the
deflection of an electron

569
00:24:40,440 --> 00:24:42,840
doesn't stop them as much.

570
00:24:42,840 --> 00:24:47,990
And so that way, more of these
proton and alpha radiolysis

571
00:24:47,990 --> 00:24:49,760
products are going to
be more spread out.

572
00:24:49,760 --> 00:24:52,760
So you get the same
number per 100 MeV,

573
00:24:52,760 --> 00:24:55,880
in the MeV range, as
you do for electrons

574
00:24:55,880 --> 00:24:58,900
at a much lower energy.

575
00:24:58,900 --> 00:25:00,900
But then alphas also have
this interesting thing

576
00:25:00,900 --> 00:25:03,420
that they're doubly charged,
so that those coulomb

577
00:25:03,420 --> 00:25:05,550
forces, remember
it's by Z squared,

578
00:25:05,550 --> 00:25:07,870
so it's four times as strong.

579
00:25:07,870 --> 00:25:10,940
So, let's see, how
do they compare?

580
00:25:10,940 --> 00:25:11,440
Yeah.

581
00:25:11,440 --> 00:25:13,900
There aren't really enough
data to draw those nice trends

582
00:25:13,900 --> 00:25:17,830
that you could see
from electrons.

583
00:25:17,830 --> 00:25:20,380
But we do have some
other interesting trends

584
00:25:20,380 --> 00:25:23,090
in the G-values as a
function of temperature.

585
00:25:23,090 --> 00:25:27,580
So these right here are
G-values for H and OH

586
00:25:27,580 --> 00:25:31,330
by gamma rays, which
are two primary species.

587
00:25:31,330 --> 00:25:34,450
And here we've graphed them
as a function of temperature.

588
00:25:34,450 --> 00:25:37,120
Why do you think the
G-values, or the amount

589
00:25:37,120 --> 00:25:40,960
of radiolysis products that
survive a microsecond, increase

590
00:25:40,960 --> 00:25:42,122
with temperature?

591
00:25:44,960 --> 00:25:47,330
What's this a competing
force or a balance between?

592
00:25:53,910 --> 00:25:56,932
So once these products are
made, what are the two things

593
00:25:56,932 --> 00:25:57,640
that they can do?

594
00:26:04,590 --> 00:26:07,160
Anyone?

595
00:26:07,160 --> 00:26:08,660
AUDIENCE: Recombine or diffuse.

596
00:26:08,660 --> 00:26:11,630
MICHAEL SHORT:
Recombine or diffuse.

597
00:26:11,630 --> 00:26:12,920
Good.

598
00:26:12,920 --> 00:26:15,470
Which of these will
increase much more strongly

599
00:26:15,470 --> 00:26:17,170
with temperature?

600
00:26:17,170 --> 00:26:18,150
AUDIENCE: Diffusion.

601
00:26:18,150 --> 00:26:19,770
MICHAEL SHORT: Diffusion.

602
00:26:19,770 --> 00:26:22,590
If they spread out more at
higher temperature, then

603
00:26:22,590 --> 00:26:26,160
they'll separate from each
other and not recombine as much.

604
00:26:26,160 --> 00:26:28,770
So a whole bunch will
be made, no matter what,

605
00:26:28,770 --> 00:26:30,510
in a matter of femtoseconds.

606
00:26:30,510 --> 00:26:32,790
But at a higher
temperature, more of them

607
00:26:32,790 --> 00:26:36,150
diffuse away from each other
and survive the cascade,

608
00:26:36,150 --> 00:26:37,930
rather than recombining.

609
00:26:37,930 --> 00:26:42,270
And so that's why, when you look
at any primary species, H2 or H

610
00:26:42,270 --> 00:26:43,840
or anything like
that, you're going

611
00:26:43,840 --> 00:26:46,822
to see an increase in
G-values with temperature.

612
00:26:46,822 --> 00:26:48,530
What do you guys think
is going to happen

613
00:26:48,530 --> 00:26:51,110
to these secondary
byproducts with temperature?

614
00:26:51,110 --> 00:26:52,610
AUDIENCE: Decrease
with temperature.

615
00:26:52,610 --> 00:26:53,610
MICHAEL SHORT: Decrease.

616
00:26:53,610 --> 00:26:54,635
And why do you say so?

617
00:26:54,635 --> 00:26:57,010
AUDIENCE: Well, if they're
made from the primary products

618
00:26:57,010 --> 00:26:59,750
and the primary products are
surviving more because they're

619
00:26:59,750 --> 00:27:03,380
separating, then the secondary
ones are just going to be less.

620
00:27:03,380 --> 00:27:04,250
MICHAEL SHORT: Yeah.

621
00:27:04,250 --> 00:27:06,680
If the primary ones
are surviving more,

622
00:27:06,680 --> 00:27:10,110
you're not going to make
as many secondary ones.

623
00:27:10,110 --> 00:27:11,400
And that's just what we see.

624
00:27:11,400 --> 00:27:13,740
Number of free electrons
left, or especially things

625
00:27:13,740 --> 00:27:17,340
like the amount of H2O2, it's
all going to be in balance.

626
00:27:17,340 --> 00:27:19,470
And if more primaries
survive, you

627
00:27:19,470 --> 00:27:22,890
don't make as many secondaries
as a function of temperature.

628
00:27:22,890 --> 00:27:25,410
One, these heavy ones
are slower to diffuse.

629
00:27:25,410 --> 00:27:28,350
But two, they're
not made as much

630
00:27:28,350 --> 00:27:32,040
because the primaries escape
each others pull and go off

631
00:27:32,040 --> 00:27:33,570
to damage something else.

632
00:27:33,570 --> 00:27:36,840
In a reactor, this would be
metals causing oxidation.

633
00:27:36,840 --> 00:27:40,270
In a body this would be you.

634
00:27:40,270 --> 00:27:42,470
And so let's get into the
materials aspect of this

635
00:27:42,470 --> 00:27:43,910
to give you a more--

636
00:27:43,910 --> 00:27:45,920
a less biologically
damaging view

637
00:27:45,920 --> 00:27:48,960
of what can
radiolysis really do.

638
00:27:48,960 --> 00:27:52,010
It's quite relevant to
all reactors, including

639
00:27:52,010 --> 00:27:53,660
the Fukushima reactor.

640
00:27:53,660 --> 00:27:55,460
The idea there is
that the reactor

641
00:27:55,460 --> 00:27:58,370
was flooded with seawater,
which introduces chlorine,

642
00:27:58,370 --> 00:28:00,680
which greatly
changes the balance

643
00:28:00,680 --> 00:28:02,830
of radiolytic byproducts.

644
00:28:02,830 --> 00:28:05,700
And this can actually
be directly studied.

645
00:28:05,700 --> 00:28:08,030
There's an experiment
just a few years ago--

646
00:28:08,030 --> 00:28:10,400
two years ago, where
they wanted to figure out

647
00:28:10,400 --> 00:28:13,310
what is the influence of
radiolysis on corrosion?

648
00:28:13,310 --> 00:28:17,150
If you're making all of
these Hs and OH-s and H2O+s,

649
00:28:17,150 --> 00:28:19,220
does it change the
corrosion rate of materials

650
00:28:19,220 --> 00:28:20,420
in the reactor?

651
00:28:20,420 --> 00:28:22,315
So they built a
high-pressure cell,

652
00:28:22,315 --> 00:28:24,440
that they fill with
high-pressure, high-temperature

653
00:28:24,440 --> 00:28:25,460
water.

654
00:28:25,460 --> 00:28:29,000
And they've got this little disk
of metal with a thin membrane

655
00:28:29,000 --> 00:28:29,720
right there.

656
00:28:29,720 --> 00:28:32,660
It's thin enough that
protons can pass through it

657
00:28:32,660 --> 00:28:35,600
and cause radiolysis to occur
right in this little pocket

658
00:28:35,600 --> 00:28:37,490
where the water is.

659
00:28:37,490 --> 00:28:40,370
And so where the protons
are, you get radiolysis.

660
00:28:40,370 --> 00:28:42,950
Where the protons aren't,
you get regular old water

661
00:28:42,950 --> 00:28:45,530
corrosion.

662
00:28:45,530 --> 00:28:47,840
And the results are
pretty astounding.

663
00:28:47,840 --> 00:28:53,490
You can see the irradiated
zone in extra oxide thickness.

664
00:28:53,490 --> 00:28:55,160
So you can see where
the protons were

665
00:28:55,160 --> 00:28:57,950
because radiolysis
sped up the corrosion

666
00:28:57,950 --> 00:28:59,900
rate as a single effect.

667
00:28:59,900 --> 00:29:03,710
Right nearby, not
100 microns away,

668
00:29:03,710 --> 00:29:07,100
was the same water, at the same
temperature and pressure, just

669
00:29:07,100 --> 00:29:10,610
no protons and no radiolysis.

670
00:29:10,610 --> 00:29:13,220
To look at a cross-section,
you can very clearly

671
00:29:13,220 --> 00:29:15,890
see the difference
in oxide thickness

672
00:29:15,890 --> 00:29:19,230
way out in the unirradiated
zone or in the irradiated zone.

673
00:29:19,230 --> 00:29:21,500
And you can tell
right here how many

674
00:29:21,500 --> 00:29:23,870
protons there were,
until right over here

675
00:29:23,870 --> 00:29:25,340
where there were none.

676
00:29:25,340 --> 00:29:27,530
So it's a very striking
example of, well,

677
00:29:27,530 --> 00:29:30,080
this is what radiolysis
does in reactors.

678
00:29:30,080 --> 00:29:31,700
And we actually do
things in reactors

679
00:29:31,700 --> 00:29:33,890
to suppress radiolysis.

680
00:29:33,890 --> 00:29:35,990
We inject hydrogen gas.

681
00:29:35,990 --> 00:29:39,500
So there's a hydrogen gas
overpressure injected.

682
00:29:39,500 --> 00:29:42,995
One of the main reasons
is to suppress radiolysis.

683
00:29:42,995 --> 00:29:47,960
Because if I jump back to any of
these reactions, a lot of them

684
00:29:47,960 --> 00:29:50,220
involve H2.

685
00:29:50,220 --> 00:29:54,750
And if you dump a whole
bunch of H2 into the reactor,

686
00:29:54,750 --> 00:29:58,950
you push the reaction backwards
in the other direction.

687
00:29:58,950 --> 00:30:01,920
From straight up chemistry,
if you add a reactant

688
00:30:01,920 --> 00:30:03,930
and add a product, you
push the equilibrium

689
00:30:03,930 --> 00:30:05,380
in the other direction.

690
00:30:05,380 --> 00:30:08,010
That's why we do this in
terms of injecting hydrogen

691
00:30:08,010 --> 00:30:09,677
into light water reactors.

692
00:30:09,677 --> 00:30:11,760
And if you look at the
amount of hydrogen injected

693
00:30:11,760 --> 00:30:15,930
in a PWR, a pressurized water
reactor, which comprises 2/3

694
00:30:15,930 --> 00:30:17,580
of the reactors in
the country, it's

695
00:30:17,580 --> 00:30:20,940
like 20 to 30 cubic centimeters
per kilogram of dissolved

696
00:30:20,940 --> 00:30:23,310
hydrogen. That's quite a bit.

697
00:30:23,310 --> 00:30:26,400
And the whole idea there
is to suppress radiolysis

698
00:30:26,400 --> 00:30:29,638
and suppress corrosion.

699
00:30:29,638 --> 00:30:30,930
So I find it to be pretty cool.

700
00:30:30,930 --> 00:30:32,940
So a knowledge of G-values
can keep your reactor

701
00:30:32,940 --> 00:30:35,470
from corroding.

702
00:30:35,470 --> 00:30:37,750
Then let's get into
the biological effects.

703
00:30:37,750 --> 00:30:40,000
In the end, for the
long-term effect

704
00:30:40,000 --> 00:30:43,210
it's all about what
happens to DNA.

705
00:30:43,210 --> 00:30:46,180
Because if a cell
mutates, it can either

706
00:30:46,180 --> 00:30:49,120
kill the cell so that
it can't replicate,

707
00:30:49,120 --> 00:30:50,770
or you can cause a
mutation that might

708
00:30:50,770 --> 00:30:54,250
make some sort of a change and
change the cell's function.

709
00:30:54,250 --> 00:30:56,200
And so you may imagine,
a lot of this stuff

710
00:30:56,200 --> 00:30:58,990
is done in LET, linear
energy transfer.

711
00:30:58,990 --> 00:31:01,310
Again, another word
for stopping power.

712
00:31:01,310 --> 00:31:04,390
If you look at the density
of these damaged cascades

713
00:31:04,390 --> 00:31:07,900
as a function of
stopping power, LET.

714
00:31:07,900 --> 00:31:12,700
You can see that for high-energy
electrons, or beta particles,

715
00:31:12,700 --> 00:31:14,890
they just bounce around
with a lot of distance

716
00:31:14,890 --> 00:31:19,300
between interactions, causing
very relatively little damage

717
00:31:19,300 --> 00:31:20,530
on the way.

718
00:31:20,530 --> 00:31:23,170
For Auger electrons,
again electrons,

719
00:31:23,170 --> 00:31:24,720
but at a much lower energy.

720
00:31:24,720 --> 00:31:27,458
They're at the end of
their stopping power curve

721
00:31:27,458 --> 00:31:29,500
and they cause a lot more
damage wherever they're

722
00:31:29,500 --> 00:31:32,000
emitted because already, they're
going to make a much denser

723
00:31:32,000 --> 00:31:33,430
damage cascade.

724
00:31:33,430 --> 00:31:36,910
Alpha particles just
go slamming through.

725
00:31:36,910 --> 00:31:39,202
It's like rolling a tank
through your cell pretty much.

726
00:31:39,202 --> 00:31:41,243
Because there's going to
be a ton of interactions

727
00:31:41,243 --> 00:31:42,940
from charged particle
interactions,

728
00:31:42,940 --> 00:31:45,610
you won't really change
the path of that alpha

729
00:31:45,610 --> 00:31:47,920
because an electron imparts
very little momentum

730
00:31:47,920 --> 00:31:49,420
to an alpha particle.

731
00:31:49,420 --> 00:31:53,120
And if DNA happens to be in the
way, it's going to get damaged.

732
00:31:53,120 --> 00:31:54,700
This is a lot of
the reason why there

733
00:31:54,700 --> 00:31:58,780
is relative effectiveness of
different types of radiation.

734
00:31:58,780 --> 00:32:01,420
We talked last week about
these quality factors,

735
00:32:01,420 --> 00:32:05,080
gamma rays are 1 electrons
tend to be pretty close to 1

736
00:32:05,080 --> 00:32:07,280
alphas tend to be 20.

737
00:32:07,280 --> 00:32:09,340
Because the same
energy alpha particle

738
00:32:09,340 --> 00:32:13,300
will impart a ton more damage
locally than the same energy

739
00:32:13,300 --> 00:32:15,207
beta particle.

740
00:32:15,207 --> 00:32:17,540
So can you guys see visually
where these quality factors

741
00:32:17,540 --> 00:32:19,760
come from?

742
00:32:19,760 --> 00:32:21,620
Cool.

743
00:32:21,620 --> 00:32:25,250
And there's two types of DNA
damage, direct and indirect.

744
00:32:25,250 --> 00:32:27,340
Direct damage is
what you might think

745
00:32:27,340 --> 00:32:31,120
radiation comes in and
ionizes something in the DNA,

746
00:32:31,120 --> 00:32:33,790
either causing, let's say,
2 thymine-based bridge,

747
00:32:33,790 --> 00:32:36,460
like a kink in the
DNA, or destroying it

748
00:32:36,460 --> 00:32:37,930
or doing anything.

749
00:32:37,930 --> 00:32:40,660
But most of the damage
is done indirectly

750
00:32:40,660 --> 00:32:43,150
because the amount of
volume of DNA in your cells

751
00:32:43,150 --> 00:32:44,870
is extremely low.

752
00:32:44,870 --> 00:32:47,590
Has anyone ever done the old
high school bio experiment,

753
00:32:47,590 --> 00:32:49,225
where you extract
DNA from onions?

754
00:32:49,225 --> 00:32:49,907
AUDIENCE: Yes.

755
00:32:49,907 --> 00:32:51,100
AUDIENCE: Strawberries.

756
00:32:51,100 --> 00:32:52,267
MICHAEL SHORT: Strawberries.

757
00:32:52,267 --> 00:32:52,810
Anything?

758
00:32:52,810 --> 00:32:55,240
So how did you do it?

759
00:32:55,240 --> 00:32:57,246
Anyone remember
how this was done?

760
00:32:57,246 --> 00:32:58,980
AUDIENCE: Some
chemicals and stuff.

761
00:32:58,980 --> 00:33:00,730
AUDIENCE: You have to
mix in good solution

762
00:33:00,730 --> 00:33:03,450
with a bunch of good
stuff and [INAUDIBLE]

763
00:33:03,450 --> 00:33:05,450
MICHAEL SHORT: So you
take, let's say, an onion,

764
00:33:05,450 --> 00:33:07,158
mix it in solution
with a bunch of stuff,

765
00:33:07,158 --> 00:33:09,290
and you end up with
this gigantic booger,

766
00:33:09,290 --> 00:33:10,620
which happens to be DNA.

767
00:33:10,620 --> 00:33:13,048
It's like a
three-foot snot thing.

768
00:33:13,048 --> 00:33:14,840
But what was the volume
of the DNA compared

769
00:33:14,840 --> 00:33:16,400
to the volume of the onion?

770
00:33:16,400 --> 00:33:17,435
AUDIENCE: Quite small.

771
00:33:17,435 --> 00:33:18,560
MICHAEL SHORT: Quite small.

772
00:33:18,560 --> 00:33:20,670
There's not a lot
of DNA in cells.

773
00:33:20,670 --> 00:33:23,330
So the direct damage
route, while still there,

774
00:33:23,330 --> 00:33:26,180
comprises very little of
the damage done to tissue.

775
00:33:26,180 --> 00:33:28,430
Mostly it's indirect
because surrounding

776
00:33:28,430 --> 00:33:32,060
all DNA is the rest of
your cellular fluid, which

777
00:33:32,060 --> 00:33:33,950
consists mostly of water.

778
00:33:33,950 --> 00:33:37,520
And as we've seen all today,
water undergoes radiolysis.

779
00:33:37,520 --> 00:33:41,210
Those radiolytic byproducts can
diffuse, find their way to DNA,

780
00:33:41,210 --> 00:33:43,490
and cause the same
sort of ionization

781
00:33:43,490 --> 00:33:45,560
that direct radiation would do.

782
00:33:45,560 --> 00:33:47,420
And since that volume
is much larger,

783
00:33:47,420 --> 00:33:51,230
let's say the hollow cylinder
of water surrounding your DNA,

784
00:33:51,230 --> 00:33:53,800
this is the most likely
route to cellular damage.

785
00:33:57,190 --> 00:33:58,180
And--

786
00:33:58,180 --> 00:34:00,430
Actually I want to skip ahead
to something real quick,

787
00:34:00,430 --> 00:34:03,640
you can actually use
that to your advantage

788
00:34:03,640 --> 00:34:05,830
because it can kill tumor cells.

789
00:34:05,830 --> 00:34:10,429
So tumors are rapidly dividing
masses of cancer cells.

790
00:34:10,429 --> 00:34:11,949
If those cells are
rapidly dividing,

791
00:34:11,949 --> 00:34:15,199
then DNA is being replicated
much more readily.

792
00:34:15,199 --> 00:34:18,550
So you can inject
something that will

793
00:34:18,550 --> 00:34:21,159
bind to DNA, like this
little chemical right

794
00:34:21,159 --> 00:34:25,510
here, this Iodine-125,
whatever, whatever, which

795
00:34:25,510 --> 00:34:29,380
mimics thymidine, something
that would be found in your DNA,

796
00:34:29,380 --> 00:34:31,780
but absorbs radiation
much better.

797
00:34:31,780 --> 00:34:34,300
So you can inject this
iodine-containing organic

798
00:34:34,300 --> 00:34:36,670
molecule, which
binds somehow to DNA.

799
00:34:36,670 --> 00:34:39,550
I'm not going to even
guess how it works.

800
00:34:39,550 --> 00:34:42,850
But, if you want
this to get damaged,

801
00:34:42,850 --> 00:34:45,820
then you want-- let's say, your
DNA to get preferably damaged,

802
00:34:45,820 --> 00:34:47,488
the tumors are
replicating faster,

803
00:34:47,488 --> 00:34:49,780
they're going to incur more
damage from the same amount

804
00:34:49,780 --> 00:34:50,830
of radiation.

805
00:34:50,830 --> 00:34:53,080
So the same process
that causes cancer

806
00:34:53,080 --> 00:34:57,980
can be used to cure cancer,
interestingly enough.

807
00:34:57,980 --> 00:35:00,950
And so, good, we do have
about 10 or 12 minutes

808
00:35:00,950 --> 00:35:02,960
to talk pseudoscience.

809
00:35:02,960 --> 00:35:05,030
So now that you know
a little bit about how

810
00:35:05,030 --> 00:35:07,640
radiation can cause
cancer and mutations

811
00:35:07,640 --> 00:35:10,460
and you know a lot of the
physics behind how much energy

812
00:35:10,460 --> 00:35:12,380
do you need to
cause an ionization,

813
00:35:12,380 --> 00:35:15,210
let's start knocking off
these questions one by one.

814
00:35:15,210 --> 00:35:17,630
So, this field,
more than any, is

815
00:35:17,630 --> 00:35:21,037
fraught with garbage,
absolute garbage science.

816
00:35:21,037 --> 00:35:23,120
I won't even say pseudoscience
because that almost

817
00:35:23,120 --> 00:35:24,800
makes it sound half legit.

818
00:35:24,800 --> 00:35:29,240
Garbage, misinterpretations,
lies, poorly done studies,

819
00:35:29,240 --> 00:35:32,840
misinterpretations of
abstracts and conclusions.

820
00:35:32,840 --> 00:35:36,470
And today I'd like to
focus on cell phones

821
00:35:36,470 --> 00:35:38,570
and do they cause cancer?

822
00:35:38,570 --> 00:35:39,650
Very hot topic.

823
00:35:39,650 --> 00:35:43,310
There's lots of people with
predetermined agendas that

824
00:35:43,310 --> 00:35:45,770
want to say all electromagnetic
radiation is bad

825
00:35:45,770 --> 00:35:48,052
and we should go back
to an agrarian society

826
00:35:48,052 --> 00:35:49,010
where nothing happened.

827
00:35:49,010 --> 00:35:51,020
Well, I'll give you a
hint, Cambodia tried that

828
00:35:51,020 --> 00:35:53,750
and it didn't turn out too well.

829
00:35:53,750 --> 00:35:59,050
People have interesting notions
of what's real and what's not.

830
00:35:59,050 --> 00:36:02,860
So let's start looking
at some of these.

831
00:36:02,860 --> 00:36:07,740
There's an article written by
this fellow, Lloyd Burrell,

832
00:36:07,740 --> 00:36:10,260
around November, 2014.

833
00:36:10,260 --> 00:36:13,800
It looks like it was
republished somewhere in 2016.

834
00:36:13,800 --> 00:36:16,260
Let's just start
looking at the facts.

835
00:36:16,260 --> 00:36:18,300
So, what I want to
start doing here

836
00:36:18,300 --> 00:36:22,790
is cultivating your nose to
be able to smell bullshit

837
00:36:22,790 --> 00:36:25,530
because this is a lot of what
you're going to be doing,

838
00:36:25,530 --> 00:36:26,820
in terms of public outreach.

839
00:36:26,820 --> 00:36:28,860
As nuclear scientists
you will be called on

840
00:36:28,860 --> 00:36:32,430
to provide expert advice and say
whether things are real or not,

841
00:36:32,430 --> 00:36:34,740
explain why, and do it
in an empathetic way

842
00:36:34,740 --> 00:36:38,010
so as not to make
people feel stupid.

843
00:36:38,010 --> 00:36:41,070
Because it's very easy for
someone to read this and think,

844
00:36:41,070 --> 00:36:42,690
yeah, I should be afraid.

845
00:36:42,690 --> 00:36:43,770
Cell phones cause cancer.

846
00:36:43,770 --> 00:36:46,592
It's a natural reaction to feel.

847
00:36:46,592 --> 00:36:48,300
Let's take a look at
some of these facts.

848
00:36:48,300 --> 00:36:52,170
Cell phones emit microwave
radio-frequency radiation.

849
00:36:52,170 --> 00:36:54,615
True or false?

850
00:36:54,615 --> 00:36:55,240
AUDIENCE: True.

851
00:36:55,240 --> 00:36:56,150
MICHAEL SHORT: True.

852
00:36:56,150 --> 00:36:56,840
Yeah.

853
00:36:56,840 --> 00:36:59,600
These are microwave
emitters, or RF emitters.

854
00:36:59,600 --> 00:37:04,690
What sort of energy is
microwave radiation emitted at?

855
00:37:04,690 --> 00:37:09,184
Just give me an order of
magnitude, MeV, eV, keV.

856
00:37:09,184 --> 00:37:10,570
AUDIENCE: MeV?

857
00:37:10,570 --> 00:37:12,400
MICHAEL SHORT: Little MeV.

858
00:37:12,400 --> 00:37:14,170
Fractions of an eV.

859
00:37:14,170 --> 00:37:16,120
It's far beyond
the visible range

860
00:37:16,120 --> 00:37:18,010
in the lower energy spectrum.

861
00:37:18,010 --> 00:37:22,270
Can a milli-electron-volt photon
cause an ionization directly?

862
00:37:22,270 --> 00:37:23,260
AUDIENCE: No.

863
00:37:23,260 --> 00:37:24,280
MICHAEL SHORT: No.

864
00:37:24,280 --> 00:37:28,030
Microwaves and RF
non-ionizing radiation.

865
00:37:28,030 --> 00:37:31,060
They can cook things
by heating up water,

866
00:37:31,060 --> 00:37:33,370
but they do not cause
ionizations the way

867
00:37:33,370 --> 00:37:35,500
that ionizing radiation does.

868
00:37:35,500 --> 00:37:38,740
This radiation has an ability
to penetrate our bodies.

869
00:37:38,740 --> 00:37:39,460
True or false?

870
00:37:39,460 --> 00:37:40,312
AUDIENCE: Yeah, [INAUDIBLE]

871
00:37:40,312 --> 00:37:40,812
True.

872
00:37:40,812 --> 00:37:42,180
MICHAEL SHORT: True.

873
00:37:42,180 --> 00:37:43,620
It gets through us, right?

874
00:37:43,620 --> 00:37:46,037
Radio waves are going
through us all the time.

875
00:37:46,037 --> 00:37:48,120
Our governments do virtually
nothing to protect us

876
00:37:48,120 --> 00:37:49,416
from these dangerous.

877
00:37:49,416 --> 00:37:51,083
AUDIENCE: Technically,
but what dangers?

878
00:37:51,083 --> 00:37:52,458
MICHAEL SHORT:
Technically, true.

879
00:37:52,458 --> 00:37:53,010
Yeah.

880
00:37:53,010 --> 00:37:56,610
So this is a classic example
of fear mongering, taking

881
00:37:56,610 --> 00:37:58,500
a bunch of facts,
putting them together

882
00:37:58,500 --> 00:38:01,688
to elicit an emotional
response that is incorrect.

883
00:38:01,688 --> 00:38:03,480
And because the emotional
part of the brain

884
00:38:03,480 --> 00:38:06,900
kicks in far faster than logical
part of the brain, that's

885
00:38:06,900 --> 00:38:10,460
how we're wired, it elicits a
reaction with a predetermined

886
00:38:10,460 --> 00:38:11,640
conclusion.

887
00:38:11,640 --> 00:38:13,770
And yet, there is strong
evidence, multiple peer

888
00:38:13,770 --> 00:38:14,520
reviewed studies--

889
00:38:14,520 --> 00:38:16,645
I'm not even going to read
the rest of the sentence

890
00:38:16,645 --> 00:38:18,690
because I don't want to
go on record saying it

891
00:38:18,690 --> 00:38:19,890
as if it were true.

892
00:38:19,890 --> 00:38:22,680
Let's, instead,
look at the studies,

893
00:38:22,680 --> 00:38:24,840
because that is the stuff
that we should trust.

894
00:38:24,840 --> 00:38:26,940
AUDIENCE: [INAUDIBLE]
44 studies.

895
00:38:26,940 --> 00:38:28,700
MICHAEL SHORT: 44 studies cited.

896
00:38:28,700 --> 00:38:31,260
And let's look at
some of the reasons.

897
00:38:31,260 --> 00:38:34,140
Let's see, there's
a little bit--

898
00:38:34,140 --> 00:38:35,690
I have to make it
a little smaller.

899
00:38:35,690 --> 00:38:38,253
Can you guys still
read that at the back?

900
00:38:38,253 --> 00:38:39,920
Or actually, no, make
it a little bigger

901
00:38:39,920 --> 00:38:42,380
and forget the sidebar.

902
00:38:42,380 --> 00:38:43,420
That's better.

903
00:38:43,420 --> 00:38:45,580
OK.

904
00:38:45,580 --> 00:38:47,932
I was going to pick a
couple of these to show you

905
00:38:47,932 --> 00:38:50,140
and I started going through
them and my favorite ones

906
00:38:50,140 --> 00:38:51,520
are all of them.

907
00:38:51,520 --> 00:38:53,920
Most of the studies are
perfectly legitimate,

908
00:38:53,920 --> 00:38:55,540
some of them are not.

909
00:38:55,540 --> 00:38:57,970
Most of the interpretations
by this Lloyd fellow

910
00:38:57,970 --> 00:39:00,580
are absolutely wrong,
and either done

911
00:39:00,580 --> 00:39:03,520
ignorantly, which
somewhat forgivable,

912
00:39:03,520 --> 00:39:05,980
it can be hard to parse these
studies, or intentionally.

913
00:39:05,980 --> 00:39:07,900
We don't know which one.

914
00:39:07,900 --> 00:39:09,220
Let's look here.

915
00:39:09,220 --> 00:39:11,170
"Telecoms giant," et
cetera, "commissioned

916
00:39:11,170 --> 00:39:15,328
an independent study--"
404, not found.

917
00:39:15,328 --> 00:39:16,370
Let's go to the next one.

918
00:39:16,370 --> 00:39:18,680
We can't conclude
anything from that.

919
00:39:18,680 --> 00:39:24,500
The Interphone Study found
that: "regular cell phone use

920
00:39:24,500 --> 00:39:26,540
significantly increased
the risk of gliomas,"

921
00:39:26,540 --> 00:39:32,610
some type of tumor, "by 40% with
1,640 hours or more of use."

922
00:39:32,610 --> 00:39:35,745
Let's look at the key figure,
taken from this paper,

923
00:39:35,745 --> 00:39:37,120
and blow it up so
you can see it.

924
00:39:39,910 --> 00:39:42,600
What do you guys notice
about this figure?

925
00:39:42,600 --> 00:39:43,475
AUDIENCE: [INAUDIBLE]

926
00:39:43,475 --> 00:39:45,102
AUDIENCE: It's so [INAUDIBLE].

927
00:39:45,102 --> 00:39:46,810
MICHAEL SHORT: Forget
the low resolution.

928
00:39:46,810 --> 00:39:48,820
We can't knock that
because it might be a copy.

929
00:39:48,820 --> 00:39:50,890
No error bars.

930
00:39:50,890 --> 00:39:52,810
And what does most
of this cell phone

931
00:39:52,810 --> 00:39:55,090
use-- and the unit
not shown here is,

932
00:39:55,090 --> 00:39:56,718
I think it's like hours of use?

933
00:39:56,718 --> 00:39:58,135
AUDIENCE: It's all
about the same.

934
00:39:58,135 --> 00:39:59,960
It's basically all the same.

935
00:39:59,960 --> 00:40:00,832
MICHAEL SHORT: Yeah.

936
00:40:00,832 --> 00:40:02,790
AUDIENCE: [INAUDIBLE] by
any chance [INAUDIBLE]

937
00:40:02,790 --> 00:40:03,220
AUDIENCE: The never is
actually closest to the 1.

938
00:40:03,220 --> 00:40:05,920
MICHAEL SHORT:
Except for this one.

939
00:40:05,920 --> 00:40:07,390
Blue line is odds ratio.

940
00:40:07,390 --> 00:40:10,430
A lot of these things are
given in OR, or odds ratio.

941
00:40:10,430 --> 00:40:12,710
Let's say the
fractional-- or let's

942
00:40:12,710 --> 00:40:15,670
say the multiplying factor
for increased risk of finding

943
00:40:15,670 --> 00:40:20,040
cancer in the variable group
compared to the control group.

944
00:40:20,040 --> 00:40:22,150
And control and variable
are interesting topics

945
00:40:22,150 --> 00:40:24,370
I want to make sure people have.

946
00:40:24,370 --> 00:40:29,640
So we have the Interphone Study
cited in many of these papers.

947
00:40:29,640 --> 00:40:30,140
Let's see.

948
00:40:30,140 --> 00:40:30,640
OK.

949
00:40:30,640 --> 00:40:32,460
Garbage, garbage,
opinions, opinions.

950
00:40:32,460 --> 00:40:34,560
Let's go find the study.

951
00:40:34,560 --> 00:40:38,260
This is something I wish people
did more, is go to the study

952
00:40:38,260 --> 00:40:38,760
itself.

953
00:40:42,360 --> 00:40:43,550
Yeah, the Interphone Study.

954
00:40:46,514 --> 00:40:48,490
AUDIENCE: Overall,
no increase in risk.

955
00:40:48,490 --> 00:40:49,350
[LAUGHTER]

956
00:40:49,350 --> 00:40:53,260
MICHAEL SHORT: We'll make this
bigger to make it more obvious.

957
00:40:53,260 --> 00:40:56,305
So many people-- this article's
been cited almost 500 times.

958
00:40:56,305 --> 00:40:58,680
I don't know in what capacity
because I haven't looked up

959
00:40:58,680 --> 00:40:59,730
every citation.

960
00:40:59,730 --> 00:41:02,190
But a lot of what this
site and other sites do

961
00:41:02,190 --> 00:41:05,760
is cite the Interphone Study to
say cell phones cause cancer.

962
00:41:05,760 --> 00:41:09,425
Read the conclusion.

963
00:41:09,425 --> 00:41:10,922
AUDIENCE: Rise of an era.

964
00:41:10,922 --> 00:41:13,668
Prevent [INAUDIBLE]
interpretation.

965
00:41:13,668 --> 00:41:14,460
MICHAEL SHORT: Yes.

966
00:41:14,460 --> 00:41:17,410
So this study is
not a bogus study.

967
00:41:17,410 --> 00:41:20,200
The study was done
correctly, reporting

968
00:41:20,200 --> 00:41:24,960
ORs, these odds ratios, with
95% confidence intervals.

969
00:41:24,960 --> 00:41:27,630
If you just look at
the numbers itself,

970
00:41:27,630 --> 00:41:32,970
oh man, 1.15 odds ratio, 15%
higher incidence of cancer,

971
00:41:32,970 --> 00:41:36,300
with a confidence interval
that includes less and more.

972
00:41:36,300 --> 00:41:41,190
So you cannot conclude with 95%
confidence that this data is

973
00:41:41,190 --> 00:41:42,000
correct.

974
00:41:42,000 --> 00:41:44,820
And the authors
very honestly say,

975
00:41:44,820 --> 00:41:49,660
no conclusion can be drawn,
require further investigation.

976
00:41:49,660 --> 00:41:52,851
What does this Lloyd fellow say?

977
00:41:52,851 --> 00:41:54,800
AUDIENCE: Cancer.

978
00:41:54,800 --> 00:41:55,740
MICHAEL SHORT: Cancer.

979
00:41:55,740 --> 00:41:57,220
Yeah.

980
00:41:57,220 --> 00:42:00,490
An either accidental or
deliberate misinterpretation

981
00:42:00,490 --> 00:42:01,930
of the data.

982
00:42:01,930 --> 00:42:05,270
OK, let's go to numbers 2 and 3.

983
00:42:05,270 --> 00:42:09,060
I don't need those anymore.

984
00:42:09,060 --> 00:42:10,290
Let's see, number 2.

985
00:42:10,290 --> 00:42:11,280
Oh, we did number 2.

986
00:42:11,280 --> 00:42:13,957
Number 3, again from
the Interphone Study.

987
00:42:13,957 --> 00:42:15,540
We can discount that
because we've now

988
00:42:15,540 --> 00:42:17,332
read the conclusion of
the study and looked

989
00:42:17,332 --> 00:42:18,525
at a bit of the difference.

990
00:42:18,525 --> 00:42:21,312
AUDIENCE: [INAUDIBLE]

991
00:42:21,312 --> 00:42:23,520
MICHAEL SHORT: Number 4,
"Harmful Association Between

992
00:42:23,520 --> 00:42:26,132
Cell Phone Risk and Tumors."

993
00:42:26,132 --> 00:42:30,326
AUDIENCE: [INAUDIBLE]

994
00:42:30,326 --> 00:42:31,571
MICHAEL SHORT: Let's see.

995
00:42:31,571 --> 00:42:32,988
AUDIENCE: It says
there's possible

996
00:42:32,988 --> 00:42:33,780
AUDIENCE: Possible.

997
00:42:33,780 --> 00:42:35,724
Studies providing a
higher level of evidence

998
00:42:35,724 --> 00:42:37,140
are needed [INAUDIBLE].

999
00:42:37,140 --> 00:42:39,130
MICHAEL SHORT: Again,
honest authors.

1000
00:42:39,130 --> 00:42:42,370
I applaud the authors for
taking a controversial topic,

1001
00:42:42,370 --> 00:42:44,910
doing a fair bit of data,
with at least enough metadata

1002
00:42:44,910 --> 00:42:48,160
analysis, I think the sample
size is OK, and then saying,

1003
00:42:48,160 --> 00:42:50,750
higher level of
evidence is needed.

1004
00:42:50,750 --> 00:42:52,240
What does the internet say?

1005
00:42:56,590 --> 00:42:59,530
It takes the one
sentence that they

1006
00:42:59,530 --> 00:43:03,390
want to support their
predetermined conclusion.

1007
00:43:03,390 --> 00:43:05,820
Very dishonest, if you ask me.

1008
00:43:05,820 --> 00:43:06,630
Number 5.

1009
00:43:06,630 --> 00:43:07,812
Oh, this is fun.

1010
00:43:07,812 --> 00:43:09,290
OK.

1011
00:43:09,290 --> 00:43:10,430
What does number 5 say?

1012
00:43:10,430 --> 00:43:11,122
AUDIENCE: Does this not
just make you angry?

1013
00:43:11,122 --> 00:43:11,470
MICHAEL SHORT: Huh?

1014
00:43:11,470 --> 00:43:12,700
AUDIENCE: Does this not
just make you angry?

1015
00:43:12,700 --> 00:43:14,408
MICHAEL SHORT: Yes it
does make me angry.

1016
00:43:14,408 --> 00:43:16,000
This is why I'm
showing it to you.

1017
00:43:16,000 --> 00:43:17,500
- infuriating, right?

1018
00:43:17,500 --> 00:43:22,000
But some of the
comparisons between what

1019
00:43:22,000 --> 00:43:24,460
the folks on the internet
will say with the sentence

1020
00:43:24,460 --> 00:43:28,640
that they want to
say- and then you

1021
00:43:28,640 --> 00:43:30,260
go to the actual
study, which they do

1022
00:43:30,260 --> 00:43:33,410
give you the link for,
"a consistent pattern

1023
00:43:33,410 --> 00:43:35,840
of increased risk associated
with wireless phones."

1024
00:43:35,840 --> 00:43:37,250
What does the study say?

1025
00:43:46,538 --> 00:43:47,580
Take a sec to parse this.

1026
00:43:47,580 --> 00:43:48,788
I'll make it a little bigger.

1027
00:43:59,210 --> 00:44:03,760
When you see an odds ratio
of, let's say, greater than 1.

1028
00:44:03,760 --> 00:44:05,186
And see a confidence interval--

1029
00:44:05,186 --> 00:44:06,186
AUDIENCE: Oh, holy crap.

1030
00:44:06,186 --> 00:44:06,682
AUDIENCE: Oh!

1031
00:44:06,682 --> 00:44:07,182
[INAUDIBLE]

1032
00:44:07,182 --> 00:44:08,330
MICHAEL SHORT: Yeah.

1033
00:44:08,330 --> 00:44:12,440
Again, another odds ratio and
another confidence interval.

1034
00:44:12,440 --> 00:44:15,740
Another odds ratio, another
confidence interval.

1035
00:44:15,740 --> 00:44:17,990
AUDIENCE: [INAUDIBLE]

1036
00:44:17,990 --> 00:44:19,310
MICHAEL SHORT: Interesting.

1037
00:44:19,310 --> 00:44:21,530
The one interesting
part is for what

1038
00:44:21,530 --> 00:44:23,660
they call ipsilateral
cumulative use, which

1039
00:44:23,660 --> 00:44:26,300
means a tumor found on
the same side of the head

1040
00:44:26,300 --> 00:44:29,690
as the cell phone, there is
actually a confidence interval

1041
00:44:29,690 --> 00:44:31,590
that seems to be significant.

1042
00:44:31,590 --> 00:44:34,040
So, I'm not going
to trash this study.

1043
00:44:34,040 --> 00:44:36,110
I'm going to say it's
not quite conclusive.

1044
00:44:36,110 --> 00:44:38,410
It doesn't go out and say
cell phones cause cancer,

1045
00:44:38,410 --> 00:44:40,640
despite this fellow
coming out and saying

1046
00:44:40,640 --> 00:44:42,650
cell phones cause cancer.

1047
00:44:42,650 --> 00:44:47,043
OK, moving on to
number 6, was a 404.

1048
00:44:47,043 --> 00:44:47,835
Let's just confirm.

1049
00:44:50,420 --> 00:44:53,740
Wasn't able to get
it an hour ago.

1050
00:44:53,740 --> 00:44:55,075
Oh, it's back.

1051
00:44:55,075 --> 00:44:56,200
OK, let's see what it does.

1052
00:44:56,200 --> 00:44:59,077
I don't even know what
this one's going to do.

1053
00:44:59,077 --> 00:45:00,075
AUDIENCE: [INAUDIBLE]

1054
00:45:00,075 --> 00:45:02,071
AUDIENCE: Potential [INAUDIBLE]

1055
00:45:02,071 --> 00:45:05,065
AUDIENCE: Possible
association with [INAUDIBLE]

1056
00:45:05,065 --> 00:45:07,070
AUDIENCE: What's heavy
mobile phone use?

1057
00:45:07,070 --> 00:45:08,903
MICHAEL SHORT: Heavy
mobile phone use, yeah.

1058
00:45:08,903 --> 00:45:11,190
Well, they'll define that
somewhere in the article.

1059
00:45:11,190 --> 00:45:13,190
So, some of these studies,
it's like OK, there's

1060
00:45:13,190 --> 00:45:14,607
interesting
viewpoints to be seen.

1061
00:45:14,607 --> 00:45:16,457
They shouldn't be
ignored just because we

1062
00:45:16,457 --> 00:45:18,290
have this predetermined
conclusion that cell

1063
00:45:18,290 --> 00:45:19,760
phones don't cause cancer.

1064
00:45:19,760 --> 00:45:22,190
It's important to go and
actually look at the studies

1065
00:45:22,190 --> 00:45:24,910
and decide for yourself.

1066
00:45:24,910 --> 00:45:26,500
Let's get into the fun ones.

1067
00:45:26,500 --> 00:45:28,080
Number 7.

1068
00:45:28,080 --> 00:45:33,010
"A recent study on 790,000
middle aged women found that,

1069
00:45:33,010 --> 00:45:36,700
"women who used cell phones
for ten or more years were

1070
00:45:36,700 --> 00:45:39,033
two-and-a-half times more
likely," et cetera, et cetera.

1071
00:45:39,033 --> 00:45:40,950
"Their risk increased
with the number of years

1072
00:45:40,950 --> 00:45:42,160
they used cell phones."

1073
00:45:42,160 --> 00:45:43,545
Let's look at the study.

1074
00:45:46,462 --> 00:45:47,080
OK, That's.

1075
00:45:47,080 --> 00:45:53,600
Not the study, so we need
to go find the study.

1076
00:45:53,600 --> 00:45:55,640
And that's another news
article about the study,

1077
00:45:55,640 --> 00:45:58,045
we need to go find this study.

1078
00:45:58,045 --> 00:45:59,320
Ah, finally.

1079
00:45:59,320 --> 00:46:00,200
AUDIENCE: The study.

1080
00:46:00,200 --> 00:46:01,242
MICHAEL SHORT: The study.

1081
00:46:01,242 --> 00:46:02,660
AUDIENCE: The study.

1082
00:46:02,660 --> 00:46:04,898
MICHAEL SHORT: Read
the conclusion.

1083
00:46:04,898 --> 00:46:05,830
AUDIENCE: What the--

1084
00:46:05,830 --> 00:46:07,228
I'm so bad.

1085
00:46:07,228 --> 00:46:08,880
[LAUGHTER]

1086
00:46:08,880 --> 00:46:10,630
AUDIENCE: I don't think
the people writing

1087
00:46:10,630 --> 00:46:12,770
these articles are actually
like reading these--

1088
00:46:12,770 --> 00:46:14,190
MICHAEL SHORT: No, I
don't think so either.

1089
00:46:14,190 --> 00:46:14,920
AUDIENCE: They just
look at the title

1090
00:46:14,920 --> 00:46:16,128
and they're like, [INAUDIBLE]

1091
00:46:16,128 --> 00:46:17,503
MICHAEL SHORT:
So, the best thing

1092
00:46:17,503 --> 00:46:19,610
that you can conclude
about these sorts of people

1093
00:46:19,610 --> 00:46:22,193
is that they're not reading the
studies and reporting on them.

1094
00:46:22,193 --> 00:46:24,980
If they are reading them
and not getting it right,

1095
00:46:24,980 --> 00:46:27,860
no, not everyone can
parse the science.

1096
00:46:27,860 --> 00:46:30,260
If they're reading them,
understanding them, and cherry

1097
00:46:30,260 --> 00:46:32,870
picking the facts in order
to support their conclusion,

1098
00:46:32,870 --> 00:46:34,797
that to me should be criminal.

1099
00:46:34,797 --> 00:46:37,130
We do live in a country where
there's freedom of speech.

1100
00:46:37,130 --> 00:46:39,140
You're free to say
whatever you want,

1101
00:46:39,140 --> 00:46:41,630
as long as it's not hate
speech of various kinds.

1102
00:46:41,630 --> 00:46:43,880
It doesn't have to be right.

1103
00:46:43,880 --> 00:46:45,412
You also don't have to listen.

1104
00:46:45,412 --> 00:46:47,120
So just because you
have freedom to talk,

1105
00:46:47,120 --> 00:46:49,438
doesn't mean people have
an obligation to listen.

1106
00:46:49,438 --> 00:46:51,230
And this is the problem
with a lot of this.

1107
00:46:51,230 --> 00:46:52,113
So I think my--

1108
00:46:52,113 --> 00:46:54,530
yeah, my notes for this study
was just kind of the F word.

1109
00:46:54,530 --> 00:46:57,440
It was, how do you
get the conclusion

1110
00:46:57,440 --> 00:46:59,810
from this internet
article, which

1111
00:46:59,810 --> 00:47:01,340
wrote an article
about an article

1112
00:47:01,340 --> 00:47:05,150
about an article about a study,
when the conclusion says,

1113
00:47:05,150 --> 00:47:10,490
with an excellent sample
size not associated.

1114
00:47:10,490 --> 00:47:12,420
OK.

1115
00:47:12,420 --> 00:47:14,490
We have like five or
seven minutes left,

1116
00:47:14,490 --> 00:47:15,510
so let's skip ahead.

1117
00:47:15,510 --> 00:47:19,675
I had a fun one for number 12,
cancer of the pituitary gland.

1118
00:47:19,675 --> 00:47:23,124
Let me get rid of
the other stuff.

1119
00:47:23,124 --> 00:47:24,100
AUDIENCE: [INAUDIBLE]

1120
00:47:24,100 --> 00:47:25,930
MICHAEL SHORT:
Oh, does that look

1121
00:47:25,930 --> 00:47:28,370
like a surprisingly
familiar figure?

1122
00:47:28,370 --> 00:47:29,230
AUDIENCE: Cool.

1123
00:47:29,230 --> 00:47:32,230
MICHAEL SHORT: It's another
article about the same study.

1124
00:47:32,230 --> 00:47:33,310
Let's just confirm.

1125
00:47:33,310 --> 00:47:35,590
AUDIENCE: [INAUDIBLE]
articles about--

1126
00:47:35,590 --> 00:47:36,923
MICHAEL SHORT: Oh, look at that.

1127
00:47:36,923 --> 00:47:38,560
AUDIENCE: [INAUDIBLE] papers.

1128
00:47:38,560 --> 00:47:40,390
MICHAEL SHORT: That right
there was the article written

1129
00:47:40,390 --> 00:47:41,920
about the study, where
the other link was

1130
00:47:41,920 --> 00:47:43,837
an article, written about
the article, written

1131
00:47:43,837 --> 00:47:45,080
about the study.

1132
00:47:45,080 --> 00:47:45,580
OK.

1133
00:47:45,580 --> 00:47:46,080
What else?

1134
00:47:46,080 --> 00:47:46,600
Next one.

1135
00:47:46,600 --> 00:47:48,950
Let's just keep going
in number order.

1136
00:47:48,950 --> 00:47:51,310
Israeli study about
thyroid cancer.

1137
00:47:51,310 --> 00:47:52,620
AUDIENCE: [INAUDIBLE]

1138
00:47:52,620 --> 00:47:53,670
MICHAEL SHORT: OK.

1139
00:47:53,670 --> 00:47:54,835
AUDIENCE: [INAUDIBLE]

1140
00:47:54,835 --> 00:47:57,210
MICHAEL SHORT: This appears
to be a blog, so let's search

1141
00:47:57,210 --> 00:47:59,160
for the word "Israel."

1142
00:47:59,160 --> 00:48:04,223
AUDIENCE: [INAUDIBLE]

1143
00:48:04,223 --> 00:48:06,140
MICHAEL SHORT: OK, but
first the news article.

1144
00:48:06,140 --> 00:48:09,210
So take a sec to
parse some of this.

1145
00:48:09,210 --> 00:48:12,180
"The incidence of thyroid cancer
has been increasing rapidly

1146
00:48:12,180 --> 00:48:14,655
in many countries, including
the US, Canada, and Israel."

1147
00:48:24,768 --> 00:48:26,310
I mean, one thing
to say-- let's say,

1148
00:48:26,310 --> 00:48:28,500
case control research on
this topic is warranted.

1149
00:48:28,500 --> 00:48:30,570
Sure.

1150
00:48:30,570 --> 00:48:33,240
No one's going to refute a
claim that, hey, maybe we should

1151
00:48:33,240 --> 00:48:36,820
study something properly, right?

1152
00:48:36,820 --> 00:48:38,200
Let's go a little further down.

1153
00:48:38,200 --> 00:48:41,860
Let's try to find
the actual study.

1154
00:48:41,860 --> 00:48:44,300
Where is this study?

1155
00:48:44,300 --> 00:48:46,580
Interesting.

1156
00:48:46,580 --> 00:48:50,510
The main point of the study is
that thyroid cancer and cell

1157
00:48:50,510 --> 00:48:54,344
phone usage are going
up at the same time.

1158
00:48:54,344 --> 00:48:55,340
AUDIENCE: Wow!

1159
00:48:55,340 --> 00:48:56,923
MICHAEL SHORT: This
is the point where

1160
00:48:56,923 --> 00:49:00,080
I like to say correlation does
not imply causation, and hammer

1161
00:49:00,080 --> 00:49:04,190
that point home by going to one
of my favorite blogs, Spurious

1162
00:49:04,190 --> 00:49:05,780
Correlations.

1163
00:49:05,780 --> 00:49:08,890
You can find any data set that
correlates with any other data

1164
00:49:08,890 --> 00:49:09,390
set.

1165
00:49:09,390 --> 00:49:10,880
AUDIENCE: [INAUDIBLE]

1166
00:49:10,880 --> 00:49:14,200
MICHAEL SHORT: Let's
look at some examples.

1167
00:49:14,200 --> 00:49:16,290
US spending on science,
space, and technology

1168
00:49:16,290 --> 00:49:20,280
correlates with a 99.79%
correlation of suicides

1169
00:49:20,280 --> 00:49:22,290
by hanging, strangulation,
and suffocation.

1170
00:49:22,290 --> 00:49:24,240
AUDIENCE: [INAUDIBLE]

1171
00:49:24,240 --> 00:49:25,880
MICHAEL SHORT: Correlated, yes.

1172
00:49:25,880 --> 00:49:28,140
Causal, I don't think so.

1173
00:49:28,140 --> 00:49:32,317
[INTERPOSING VOICES]

1174
00:49:32,317 --> 00:49:33,150
MICHAEL SHORT: Yeah.

1175
00:49:33,150 --> 00:49:36,930
Divorce rate in Maine correlates
with per capita consumption

1176
00:49:36,930 --> 00:49:37,500
of margarine.

1177
00:49:37,500 --> 00:49:39,840
AUDIENCE: [LAUGHTER] Michelle,
[INAUDIBLE] margarine.

1178
00:49:39,840 --> 00:49:41,610
MICHAEL SHORT: You can find
a link between anything

1179
00:49:41,610 --> 00:49:44,160
and anything else if you just
search the data long enough

1180
00:49:44,160 --> 00:49:46,199
without searching for a
mechanism or a reason.

1181
00:49:46,199 --> 00:49:47,116
AUDIENCE: That's cool.

1182
00:49:47,116 --> 00:49:49,783
Can we look at the age of
Miss America below this?

1183
00:49:49,783 --> 00:49:50,700
MICHAEL SHORT: Oh, OK.

1184
00:49:50,700 --> 00:49:52,680
Age of Miss America
correlates with murders

1185
00:49:52,680 --> 00:49:53,655
by steam, hot vapors.

1186
00:49:53,655 --> 00:49:54,155
[LAUGHTER]

1187
00:49:54,155 --> 00:49:56,370
AUDIENCE: [LAUGHTER]

1188
00:49:56,370 --> 00:49:58,620
MICHAEL SHORT: Clearly, we
should ban the Miss America

1189
00:49:58,620 --> 00:49:59,745
pageant or make them older.

1190
00:49:59,745 --> 00:50:01,433
AUDIENCE: Yeah, [INAUDIBLE].

1191
00:50:01,433 --> 00:50:03,850
MICHAEL SHORT: Or the other
way around, make them younger.

1192
00:50:03,850 --> 00:50:05,845
Maybe this is why we
have toddlers in tiaras,

1193
00:50:05,845 --> 00:50:08,460
it's to stop murders by steam.

1194
00:50:08,460 --> 00:50:09,660
Oh, my God.

1195
00:50:09,660 --> 00:50:10,160
OK.

1196
00:50:10,160 --> 00:50:11,450
AUDIENCE: [INAUDIBLE]

1197
00:50:11,450 --> 00:50:12,110
MICHAEL SHORT: So
this is, again,

1198
00:50:12,110 --> 00:50:13,818
the point where you
have to ask yourself,

1199
00:50:13,818 --> 00:50:16,250
what are the other confounding
variables in this study?

1200
00:50:16,250 --> 00:50:20,490
Why else could thyroid
cancer be going up?

1201
00:50:20,490 --> 00:50:21,706
Anyone?

1202
00:50:21,706 --> 00:50:23,500
I can probably come
up with like a hundred

1203
00:50:23,500 --> 00:50:25,276
different possible reasons.

1204
00:50:25,276 --> 00:50:27,478
AUDIENCE: [INAUDIBLE]

1205
00:50:27,478 --> 00:50:29,270
MICHAEL SHORT: Any sort
of other chemicals?

1206
00:50:29,270 --> 00:50:32,840
Let's say, more industrial
runoff, more urbanization,

1207
00:50:32,840 --> 00:50:35,960
smog, inhalation, some amount,
let's say, I don't know,

1208
00:50:35,960 --> 00:50:38,328
iodine released from Chernobyl
making its way through.

1209
00:50:38,328 --> 00:50:40,370
Now, that would have had
like a 30-day half-life.

1210
00:50:40,370 --> 00:50:41,910
AUDIENCE: [INAUDIBLE]

1211
00:50:41,910 --> 00:50:44,285
MICHAEL SHORT: Yeah, that's
also got to pretty much decay

1212
00:50:44,285 --> 00:50:46,330
by now.

1213
00:50:46,330 --> 00:50:48,130
Yeah, there could be
any number of reasons.

1214
00:50:48,130 --> 00:50:51,400
And just to say cell phones and
thyroid cancer are correlated,

1215
00:50:51,400 --> 00:50:54,100
is like saying this.

1216
00:50:54,100 --> 00:50:54,600
What else?

1217
00:50:54,600 --> 00:50:56,450
AUDIENCE: [INAUDIBLE]

1218
00:50:56,450 --> 00:50:58,200
MICHAEL SHORT: This I
think might actually

1219
00:50:58,200 --> 00:50:59,197
have something to--

1220
00:50:59,197 --> 00:51:00,030
AUDIENCE: [LAUGHTER]

1221
00:51:00,030 --> 00:51:01,920
MICHAEL SHORT: There
might be a link here.

1222
00:51:01,920 --> 00:51:03,330
Revenue generated
by arcades kids

1223
00:51:03,330 --> 00:51:05,500
with computer
science doctorates.

1224
00:51:05,500 --> 00:51:08,745
Again, just a correlation.

1225
00:51:08,745 --> 00:51:09,620
AUDIENCE: [INAUDIBLE]

1226
00:51:09,620 --> 00:51:11,920
AUDIENCE: Sociology
doctorates-- [LAUGHTER]

1227
00:51:11,920 --> 00:51:12,900
MICHAEL SHORT: Ah,
look at the amazing--

1228
00:51:12,900 --> 00:51:13,900
it's got all the same humps.

1229
00:51:13,900 --> 00:51:14,320
And everything.

1230
00:51:14,320 --> 00:51:15,895
All right, I think
I've made the point.

1231
00:51:15,895 --> 00:51:16,765
AUDIENCE: Actually,
I like the margarine

1232
00:51:16,765 --> 00:51:18,070
and the divorce rate one

1233
00:51:18,070 --> 00:51:20,403
MICHAEL SHORT: Let's go on
to some of the other studies,

1234
00:51:20,403 --> 00:51:21,926
let's say, number 15.

1235
00:51:24,430 --> 00:51:28,870
11 of 29 cases of
neuroepithelial tumors, cell

1236
00:51:28,870 --> 00:51:32,110
phone users accounted
for 11 of them."

1237
00:51:32,110 --> 00:51:35,560
11 of the 29 people in the study
that got this type of tumor

1238
00:51:35,560 --> 00:51:36,520
used cell phones.

1239
00:51:36,520 --> 00:51:37,300
What's wrong here?

1240
00:51:37,300 --> 00:51:37,750
AUDIENCE: Who doesn't
use cell phones?

1241
00:51:37,750 --> 00:51:38,708
People use cell phones.

1242
00:51:38,708 --> 00:51:40,000
Everybody uses cell phones.

1243
00:51:40,000 --> 00:51:42,032
They don't think about anything
else that could have happened?

1244
00:51:42,032 --> 00:51:42,949
MICHAEL SHORT: No, no.

1245
00:51:42,949 --> 00:51:44,890
Here, I think the
study is flawed.

1246
00:51:44,890 --> 00:51:47,895
What is the worst
part about this study?

1247
00:51:47,895 --> 00:51:48,770
AUDIENCE: [INAUDIBLE]

1248
00:51:48,770 --> 00:51:49,084
AUDIENCE: It's only 29 cases.

1249
00:51:49,084 --> 00:51:50,500
AUDIENCE: It's 29 cases.

1250
00:51:50,500 --> 00:51:53,960
MICHAEL SHORT: 29
cases, sample size.

1251
00:51:53,960 --> 00:51:57,018
If you get 11 out of 29
and say half of the tumors

1252
00:51:57,018 --> 00:51:58,810
we saw were attributed
to cell phones, that

1253
00:51:58,810 --> 00:52:00,714
is not a proper conclusion.

1254
00:52:00,714 --> 00:52:02,589
AUDIENCE: How are you
going to [INAUDIBLE] it

1255
00:52:02,589 --> 00:52:03,910
to a cell phone [INAUDIBLE]?

1256
00:52:03,910 --> 00:52:05,620
MICHAEL SHORT: Let's
see, number 17.

1257
00:52:05,620 --> 00:52:06,550
Ah, OK.

1258
00:52:06,550 --> 00:52:08,980
Another Israeli
study that talked

1259
00:52:08,980 --> 00:52:13,420
about parotid gland cancers
and salivary gland cancers.

1260
00:52:13,420 --> 00:52:15,845
My note to this is
read the last sentence.

1261
00:52:15,845 --> 00:52:20,522
AUDIENCE: [LAUGHTER] [INAUDIBLE]

1262
00:52:20,522 --> 00:52:22,939
AUDIENCE: Like, I'm sure there's
other factors [INAUDIBLE]

1263
00:52:22,939 --> 00:52:25,404
[INTERPOSING VOICES]

1264
00:52:25,404 --> 00:52:26,688
AUDIENCE: They cause cancer.

1265
00:52:26,688 --> 00:52:28,480
MICHAEL SHORT: The blog
says, cause cancer.

1266
00:52:28,480 --> 00:52:33,540
The data says, no
causal association.

1267
00:52:33,540 --> 00:52:36,240
So again, almost
criminally ignorant.

1268
00:52:36,240 --> 00:52:37,770
How many times did
you have to miss

1269
00:52:37,770 --> 00:52:40,068
the last sentence, the
conclusion of the article,

1270
00:52:40,068 --> 00:52:41,360
to pick the part that you want?

1271
00:52:41,360 --> 00:52:43,777
AUDIENCE: But everything you
read on the internet is true.

1272
00:52:43,777 --> 00:52:44,985
You know, it's [? illegal. ?]

1273
00:52:44,985 --> 00:52:46,735
MICHAEL SHORT: All I
can say is everything

1274
00:52:46,735 --> 00:52:48,660
that you read on the
internet was written.

1275
00:52:48,660 --> 00:52:49,860
That's the best I can say.

1276
00:52:49,860 --> 00:52:52,710
Number 20, we don't even
have to go to the study here.

1277
00:52:52,710 --> 00:52:53,952
AUDIENCE: [INAUDIBLE]

1278
00:52:53,952 --> 00:52:54,910
MICHAEL SHORT: Oh, boy.

1279
00:52:54,910 --> 00:52:57,148
AUDIENCE: [INAUDIBLE]
machine learning [INAUDIBLE]..

1280
00:52:57,148 --> 00:52:59,190
MICHAEL SHORT: Let's check
the study to make sure

1281
00:52:59,190 --> 00:53:00,825
that the quote is actually
correct, but before--

1282
00:53:00,825 --> 00:53:02,200
AUDIENCE: [INAUDIBLE]
Oh, my God.

1283
00:53:02,200 --> 00:53:04,213
MICHAEL SHORT: Four women.

1284
00:53:04,213 --> 00:53:05,380
AUDIENCE: It's just the one.

1285
00:53:05,380 --> 00:53:07,300
AUDIENCE: Study four women.

1286
00:53:07,300 --> 00:53:08,810
Looks like it might [INAUDIBLE]

1287
00:53:08,810 --> 00:53:11,790
MICHAEL SHORT: Yeah, by the
prestigious publication,

1288
00:53:11,790 --> 00:53:14,370
Hindawi, which
sends me more emails

1289
00:53:14,370 --> 00:53:17,400
than I read their articles.

1290
00:53:17,400 --> 00:53:19,460
So let's look at the abstract.

1291
00:53:22,850 --> 00:53:25,190
Of all four cases, they
are a case studies,

1292
00:53:25,190 --> 00:53:27,290
so striking
similarity, how hard do

1293
00:53:27,290 --> 00:53:30,380
you think it would be to find
four women with a certain type

1294
00:53:30,380 --> 00:53:32,095
of breast tumor?

1295
00:53:32,095 --> 00:53:33,887
There's a lot of women
in the world, right?

1296
00:53:33,887 --> 00:53:35,230
AUDIENCE: Yes.

1297
00:53:35,230 --> 00:53:37,480
MICHAEL SHORT: And breast
cancer is one of the leading

1298
00:53:37,480 --> 00:53:39,560
causes of cancer in women.

1299
00:53:39,560 --> 00:53:41,890
It wouldn't be hard to cherry
pick four people to get

1300
00:53:41,890 --> 00:53:43,300
the same conclusion you want.

1301
00:53:43,300 --> 00:53:44,800
Oh, and there's
another correlation,

1302
00:53:44,800 --> 00:53:47,920
out of 108 billion humans
that have ever lived and have

1303
00:53:47,920 --> 00:53:50,500
been exposed to ionizing
radiation, all of them

1304
00:53:50,500 --> 00:53:53,162
died at some point.

1305
00:53:53,162 --> 00:53:54,620
AUDIENCE: [LAUGHTER]
At some point.

1306
00:53:54,620 --> 00:53:56,078
MICHAEL SHORT: At
some point, yeah.

1307
00:53:56,078 --> 00:53:58,535
every human that's
ever lived has died.

1308
00:53:58,535 --> 00:53:59,910
And every human
that's ever lived

1309
00:53:59,910 --> 00:54:01,535
had been exposed to
ionizing radiation.

1310
00:54:01,535 --> 00:54:02,840
AUDIENCE: [INAUDIBLE]

1311
00:54:02,840 --> 00:54:04,028
AUDIENCE: It must be true.

1312
00:54:04,028 --> 00:54:05,940
[INAUDIBLE]

1313
00:54:05,940 --> 00:54:09,837
MICHAEL SHORT: Perfect
correlation, no causation.

1314
00:54:09,837 --> 00:54:10,670
Let's see, two more.

1315
00:54:10,670 --> 00:54:11,770
I think we have
time for two more.

1316
00:54:11,770 --> 00:54:12,880
This is kind of fun.

1317
00:54:12,880 --> 00:54:14,270
An eye cancer study.

1318
00:54:14,270 --> 00:54:15,560
All right, let's just go--

1319
00:54:15,560 --> 00:54:17,270
"found elevated
risk for exposure

1320
00:54:17,270 --> 00:54:19,080
to radio frequency
transmitting devices."

1321
00:54:19,080 --> 00:54:20,650
AUDIENCE: Are
these real studies?

1322
00:54:20,650 --> 00:54:22,470
Don't the authors
get mad that people

1323
00:54:22,470 --> 00:54:25,092
are using their studies wrong?

1324
00:54:25,092 --> 00:54:27,050
MICHAEL SHORT: I'm sure
the authors do get mad,

1325
00:54:27,050 --> 00:54:28,550
but what are you going
to do about some person

1326
00:54:28,550 --> 00:54:29,695
on the internet, right?

1327
00:54:29,695 --> 00:54:32,390
You can send a nasty letter
to the magazine, which

1328
00:54:32,390 --> 00:54:34,400
might reject it as hate mail.

1329
00:54:34,400 --> 00:54:35,432
OK, on the blog.

1330
00:54:35,432 --> 00:54:36,890
AUDIENCE: [INAUDIBLE]
very strong--

1331
00:54:36,890 --> 00:54:38,223
MICHAEL SHORT: What does it say?

1332
00:54:38,223 --> 00:54:40,472
Elevated risk for
exposure in the study.

1333
00:54:40,472 --> 00:54:43,525
AUDIENCE: People only get
excited by some crazy person.

1334
00:54:43,525 --> 00:54:44,900
AUDIENCE: [INAUDIBLE]
it's about.

1335
00:54:44,900 --> 00:54:46,518
[INAUDIBLE]

1336
00:54:46,518 --> 00:54:49,060
MICHAEL SHORT: I don't think I
have to make my point anymore.

1337
00:54:49,060 --> 00:54:50,643
We've gone through
about half of them.

1338
00:54:50,643 --> 00:54:54,090
I encourage the rest of you guys
to go through the other half.

1339
00:54:54,090 --> 00:54:58,950
And to the people, like
this Lloyd Burrell,

1340
00:54:58,950 --> 00:55:00,390
I say check your facts.

1341
00:55:00,390 --> 00:55:03,570
What you're doing is
criminally incompetent.

1342
00:55:03,570 --> 00:55:05,850
With the way that people
are misleading the public

1343
00:55:05,850 --> 00:55:08,100
to get whatever pre-gone
conclusions that they have

1344
00:55:08,100 --> 00:55:10,380
from their emotions or
their funding sources

1345
00:55:10,380 --> 00:55:15,630
or whatever the reason to
be, by misquoting facts

1346
00:55:15,630 --> 00:55:17,130
you're absolutely
misleading people

1347
00:55:17,130 --> 00:55:18,870
and spreading false science.

1348
00:55:18,870 --> 00:55:21,330
Because, to me, the most
exciting moments in science

1349
00:55:21,330 --> 00:55:23,700
don't end with the
words, "I told you so,"

1350
00:55:23,700 --> 00:55:26,550
but start with the words,
"that's interesting."

1351
00:55:26,550 --> 00:55:28,650
So just because the
studies that you find

1352
00:55:28,650 --> 00:55:30,840
don't support your
predetermined conclusions,

1353
00:55:30,840 --> 00:55:32,340
doesn't mean you
should reject them.

1354
00:55:32,340 --> 00:55:35,330
It means that you might
have to change your idea.

1355
00:55:35,330 --> 00:55:37,455
So, on that note, I'd
like to stop here.

1356
00:55:37,455 --> 00:55:39,080
We'll come back on
Thursday and go over

1357
00:55:39,080 --> 00:55:42,080
the short and long-term
biological effects of radiation

1358
00:55:42,080 --> 00:55:44,640
and look at some
more garbage science.

1359
00:55:44,640 --> 00:55:45,140
Yeah?

1360
00:55:45,140 --> 00:55:48,050
AUDIENCE: How do you feel
about those wireless chargers

1361
00:55:48,050 --> 00:55:49,020
they have now?

1362
00:55:49,020 --> 00:55:51,072
It's like a conductive
charger so it

1363
00:55:51,072 --> 00:55:55,063
uses like a low-branch,
strongish magnetic field.

1364
00:55:55,063 --> 00:55:55,980
MICHAEL SHORT: Mm-hmm.

1365
00:55:55,980 --> 00:55:56,848
AUDIENCE: And people
are like, oh, my God.

1366
00:55:56,848 --> 00:55:57,515
That's so scary.

1367
00:55:57,515 --> 00:55:59,598
MICHAEL SHORT: I would
just say go to the studies.

1368
00:55:59,598 --> 00:56:02,490
It's very easy to say put a
bunch of rats on a cell phone

1369
00:56:02,490 --> 00:56:05,130
charger, turn it on,
and see what happens.

1370
00:56:05,130 --> 00:56:07,020
I mean, the data doesn't lie.

1371
00:56:07,020 --> 00:56:10,100
The reason might be a
little hard to figure out.

1372
00:56:10,100 --> 00:56:10,600
Yeah.

1373
00:56:10,600 --> 00:56:11,100
Yeah.

1374
00:56:11,100 --> 00:56:12,910
So, I mean, another
thing is, when

1375
00:56:12,910 --> 00:56:14,245
people have a predetermined--

1376
00:56:14,245 --> 00:56:16,120
I know it's a little
past 10:00, but no one's

1377
00:56:16,120 --> 00:56:18,010
gotten up so I'll keep ranting.

1378
00:56:18,010 --> 00:56:20,800
So a lot of this
neo-environmentalism going on

1379
00:56:20,800 --> 00:56:23,860
has the predetermined
conclusion that only sources

1380
00:56:23,860 --> 00:56:26,410
of power light on the Earth,
like solar and wind, that

1381
00:56:26,410 --> 00:56:29,440
are renewable and such,
are the ways to go.

1382
00:56:29,440 --> 00:56:31,750
And immediately dismiss
nuclear as not part

1383
00:56:31,750 --> 00:56:34,090
of the environmental
solution, despite being part

1384
00:56:34,090 --> 00:56:35,680
of the environmental solution.

1385
00:56:35,680 --> 00:56:38,080
A large source of power
that's very efficient

1386
00:56:38,080 --> 00:56:40,090
and doesn't admit any CO2.

1387
00:56:40,090 --> 00:56:43,240
It might surprise them to
know that manufacturing wind

1388
00:56:43,240 --> 00:56:45,160
turbines is a major
source of radioactivity.

1389
00:56:45,160 --> 00:56:46,150
AUDIENCE: [INAUDIBLE]

1390
00:56:46,150 --> 00:56:47,080
MICHAEL SHORT: Anyone
want to guess where?

1391
00:56:47,080 --> 00:56:48,620
AUDIENCE: Rare-earth magnets.

1392
00:56:48,620 --> 00:56:50,880
MICHAEL SHORT: Yes, thank
you, rare-earth magnets.

1393
00:56:50,880 --> 00:56:53,620
The major cause of wind turbine
failure in the last decade

1394
00:56:53,620 --> 00:56:55,930
has been the gearboxes
breaking down.

1395
00:56:55,930 --> 00:56:57,370
Because in order
to extract power,

1396
00:56:57,370 --> 00:57:01,010
you have to gear down those
giant turbines by quite a bit.

1397
00:57:01,010 --> 00:57:04,060
And those gears, 300-feet up
in the air, tend to break down,

1398
00:57:04,060 --> 00:57:05,350
they're hard to maintain.

1399
00:57:05,350 --> 00:57:06,530
How do you fix it?

1400
00:57:06,530 --> 00:57:08,110
Make stronger magnets.

1401
00:57:08,110 --> 00:57:10,960
Put in rare-earth magnets that
electromagnetically harvest

1402
00:57:10,960 --> 00:57:13,930
the energy, instead of gearing
it down and doing the same

1403
00:57:13,930 --> 00:57:16,390
and you don't have
mechanical things grinding.

1404
00:57:16,390 --> 00:57:18,593
What are rare-earth
magnets made out of?

1405
00:57:18,593 --> 00:57:19,510
AUDIENCE: Rare-earths.

1406
00:57:19,510 --> 00:57:20,635
MICHAEL SHORT: Rare-earths.

1407
00:57:20,635 --> 00:57:23,350
Lanthanides, which happen
to be found with actinides,

1408
00:57:23,350 --> 00:57:27,160
thorium,r whatever actinium
exists, radium, uranium,

1409
00:57:27,160 --> 00:57:28,877
things with similar chemistry.

1410
00:57:28,877 --> 00:57:31,210
What do you do when you extract
the rare-earths that you

1411
00:57:31,210 --> 00:57:33,560
need from the rare-earth ore?

1412
00:57:33,560 --> 00:57:36,530
You ditch the remains, which
are concentrated sources

1413
00:57:36,530 --> 00:57:38,420
of these radioactive byproducts.

1414
00:57:38,420 --> 00:57:40,040
Where do most radioactive--

1415
00:57:40,040 --> 00:57:42,680
I'm sorry, where do most
rare-earth magnets come from?

1416
00:57:42,680 --> 00:57:43,580
AUDIENCE: China.

1417
00:57:43,580 --> 00:57:44,990
MICHAEL SHORT: China.

1418
00:57:44,990 --> 00:57:47,885
How is China's record on
environmental practices?

1419
00:57:47,885 --> 00:57:49,739
AUDIENCE: Not [INAUDIBLE].

1420
00:57:49,739 --> 00:57:50,665
[INAUDIBLE]

1421
00:57:50,665 --> 00:57:53,960
[INTERPOSING VOICES]

1422
00:57:53,960 --> 00:57:55,820
MICHAEL SHORT: Spotty, at best.

1423
00:57:55,820 --> 00:57:57,310
AUDIENCE: Questionable.

1424
00:57:57,310 --> 00:57:58,190
MICHAEL SHORT: Yeah.

1425
00:57:58,190 --> 00:58:00,560
So, again, one of those
things where people say,

1426
00:58:00,560 --> 00:58:03,632
oh, wind power has absolutely
no effect on the environment.

1427
00:58:03,632 --> 00:58:05,465
Check the radioactivity
of making windmills.

1428
00:58:05,465 --> 00:58:07,420
AUDIENCE: I want you
to tell the Sierra.

1429
00:58:07,420 --> 00:58:09,920
MICHAEL SHORT: I don't know if
the Sierra Club would listen.

1430
00:58:09,920 --> 00:58:10,795
AUDIENCE: [INAUDIBLE]

1431
00:58:10,795 --> 00:58:12,670
MICHAEL SHORT: I have
heard murmurs or rumors

1432
00:58:12,670 --> 00:58:14,870
of them coming around to
the idea of nuclear power.

1433
00:58:14,870 --> 00:58:17,210
There's an article that said
they switched positions,

1434
00:58:17,210 --> 00:58:19,502
then there was a counter
article, followed a day later,

1435
00:58:19,502 --> 00:58:21,170
that says, no, that
was a rogue actor.

1436
00:58:21,170 --> 00:58:23,720
They don't reflect the
views of the Sierra Club.

1437
00:58:23,720 --> 00:58:26,300
The problem is with all
these neo-envrionmentalists

1438
00:58:26,300 --> 00:58:28,490
and cell-phones-cause-cancer
people

1439
00:58:28,490 --> 00:58:30,140
and food-irradiation-is-evil
people,

1440
00:58:30,140 --> 00:58:33,140
you'll find them cherry picking
data to support the conclusion

1441
00:58:33,140 --> 00:58:35,650
that they already
felt they wanted.

1442
00:58:35,650 --> 00:58:37,610
And when confronted with
overwhelming evidence

1443
00:58:37,610 --> 00:58:38,870
to the contrary.

1444
00:58:38,870 --> 00:58:40,400
They don't change their view.

1445
00:58:40,400 --> 00:58:42,470
And that to me is the
best thing about science.

1446
00:58:42,470 --> 00:58:44,012
If you prove to me
that you're wrong,

1447
00:58:44,012 --> 00:58:48,340
I will say, thank
you, not [INAUDIBLE]..

1448
00:58:48,340 --> 00:58:50,280
AUDIENCE: [LAUGHTER]

1449
00:58:50,280 --> 00:58:52,490
MICHAEL SHORT: So, there you go.

1450
00:58:52,490 --> 00:58:55,270
All right, I'll see
you guys on Tuesday.