Carl's Roost:
Response to April 30 / May 1 Scratchings
General comment:
Students are getting much better about describing
their observations.
May 1: chicken little - Urbana Middle School
The eggs seem to be small. How can their big feet,
eyes and body all fit in there for 21 days? Why does
the embryo absorb the yolk sac?
Carl:
The chick doesn't "eat" anything for 21 days (and a
couple more after it hatches, usually). It lives
off the "fat of the land", using the yolk for energy
and building materials. Eventually it all gets used
up, which is a good thing, since that leaves room
for the chicken. Check out the Egg Chemistry page
for more about the yolk.
I've enjoyed working on chickscope and I hope to
do this again sometime.Is it possible to find
something that causes the images to be
clearer?
Carl:
"Clearer" is a bit vague. If you mean the blurring,
we would need either a faster MRI machine or a
slower chick. If the chick had died, the pictures
would be very crisp and clear!
April 30: Michael Newton - Col. Wolfe University
Primary School
When I was looking at picture "mri.00122.jpeg" I
discovered a "white" spot. What is it?
Carl:
You need to be more specific (like the scratchings
below). There is a tiny dot at DE/45, which is an
artifact (like dirt on the lens of a camera).
Another spot, near the shell at D2 is probably a
small blood vessel. The blurry spot at FG/45 is
probably part of the chick, but we can't tell
what.
April 30: david h., tuyet, fernanda - Urbana High
School
In image mri.00159, what is the circular
structure in quadrant E6?
Carl:
Hard to tell. Sorry. One often needs more than one
view to interpret structure from slices.
In image mri.00161 what is the structure in
quadrant E7?
Carl:
I don't see it.
April 30: Anna, Yvonne, Dasha, Rachel - Urbana
High School
The final day has arrived. Before we get started
with our observations we would just like to
welcome the chicks to this vicious world. Well,
let's keep them on the right track and let them
figure out for themselves that it is a vicious
world. Is there some way to better explain what
the images are actually of? A more precise
explanation of where we are looking on the
egg?
Carl:
I assume you mean that it is difficult to interpret
the images. That's certainly true, especially if you
only look at one at a time. You need to consider how
various structures would look if sliced in different
ways, then look for them in the other planes.
Discard images that are obviously corrupted by
motion. It takes a lot of patience. Looking at the
chick as it develops helps some, since it gives you
an idea of how big things should be, or whether they
are bright or dark.
To put this in perspective, radiologists (doctors
who look at x-rays and MRIs every day) spend years
practicing, looking at thousands of films, before
they make any diagnoses on their own. And the
subjects of their pictures are generally cooperative
(people will turn sideways if you ask them to, for
example, or hold still). And they use very
standardized poses for getting the images. The
chicken doesn't understand that. So your job is
actually harder, and you have had less practice.
It is really incredible to see how much the
embryo has changed over the period of the
project. We can see the wings in image 158. Very
impressive. Well, our session is over. It's been
fun working with you all. We hope that we can be
research partners in the near future. Best of luck
to all of you. By the way, when do our paychecks
get here?!
Carl:
Sorry, the research budget has been cut. No more
paychecks.
April 30: david gu, patar tantular, ted zhang,
helena milton - Urbana High School
#142. There is a dark spot on top. The view is
top. There is a dark spot in the center of the
white area. What is it?
Carl:
Too vague. Maybe you mean the yolk at C-F/5-6 ? It
gets darker toward the top (level 7) because the MRI
machine doesn't "illuminate" that area too well.
#148. The view is side. There might be a head in
the region of d5, what exactly is it?
Carl:
Actually, I think that was a wing or foot. The head
is at the end with the air sac.
#151 The image looks interesting. It is a top
view picture. It is very detailed. You can see
almost all the structures, including the hair and
beak.
Carl:
This has too much motion artifact (blurring) to be
very useful to me.
#152 The picture is very clear. It is divided
into several distinct sections. The embryo is
clearly visible and the embryo is curled up in one
corner. The air sac is still visible. What is the
white space in the middle.
Carl:
I think this might be the same projection you
noticed in 148. Looks more like a wing than a foot
from here.
#155 The view is side. There is a dark region in
the c5 and d5 area. the air sac is not visible and
the yolk is present.
Carl:
Right, yolk.
#158 there is a side view. The head is present
and there are ripples in the picture.
Carl:
Right.
April 30: Laura Guest and Jaime Wilson - Urbana
High School
Image 161: Is the beak in F6?
Carl:
Impossible to tell. It's the right general area of
the egg, though.
C.D.Gregory: April 24, 1996