19 MAR 2015 by ideonexus
Whole Brain Emulation
We consider a strategy of straightforward duplication of the activity, and look at the numbers of some of the components. The human brain has up to one hundred billion (10^11) neurons and between one hundred trillion (10^14) and one quadrillion (10^15) synapses. But we have reached a point where for purposes of data acquisition these objects are now considered fairly large (e.g. 200 nm to 2,000 nm for synaptic spines and 4,000 nm to 100,000 nm for the neural soma), at least by the standards o...From Randal A. Koene's "Uploading to Substrate-Independent Minds"
20 JUN 2013 by ideonexus
Relative Sizes of Structures in the Brain
Linear measure- ments and dimensions generally are given in microns or micrometers (µm) (1 µm equals one- millionth of a meter) or nanometers (nm) (1 nm or millimicron equals one-billionth of a meter). About 240,000 µm equal one inch.
As a reference, the following are the dimen-
sions of some non-neural structures: human ovum, 100 µm; cross-section of a skeletal muscle fiber, 10-100 µm; erythrocytes, 8–10 µm; bacteria, 0.1–8 µm; and viruses, 0.15–0.5 µm.
Cell bodies of neurons...Interesting to see how they compare to the sizes of other small objects.
05 JAN 2012 by ideonexus
Mathematical Proof that an Arm's Length of DNA is in Ever...
We know from X-ray diffraction studies that a strand of DNA is 1.5 nanometers (1.5 x 10 to the -9 meters) in radius. Assume a cylinder 1 meter long (the arm's length) with a radius of 1.5 nanometers and work out the volume (length x pi r-squared). A typical animal cell is about 8 micrometers (8 x 10 to the -6 meters) in radius. Assume a spherical cell and calculate the volume (4/3 pi r-cubed). Do it yourself. You will see that the DNA fits easily inside the cell, with plenty of room for all o...Folksonomies: mathematics dna
Folksonomies: mathematics dna
Chet Raymo does the math to demonstrate this seemingly impossible scientific facts.