From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Dec 11 1998 - 11:36:25 MST
Intelligent Paper
Memory effects of estrogen in rats, women and transsexuals
Architectural Considerations for Self-Replicating Manufacturing Systems
Information, evolution and "error-friendliness
Energy cost of information transmission
The maximum speed of dynamical evolution
Software/hardware/sheetware
Intelligent Paper
Marc Dymetman and Max Copperman, in Electronic Publishing, Electronic
Publishing, Artistic Imaging and Digital Typography (proceedings from
the 7th international condference on electronic publishing), St. Malo,
France, March/April 1998, Springer Lecture Notes in Computer Science
1376, Roger D. Hersch, Jacques Andre and Heather Brown (eds.)
pages 392-406
A neat idea for "smart paper" without the need for advanced
technology. Each physical page has an unique identity number and is
covered with an invisible pattern encoding the id and the location on
the page (using Xerox DataGlyphs 400 bytes of data per square inch can
be written using a 300dpi printer). On top of this a visible page is
printed. By pointing a pen-shaped camera to a place on the page, the
pen can determine which page it is, and where it is pointed. This
information is sent to a server, which looks up the web page or online
service linked to the page id (for example an interactive
encyclopedia, an online map or advertisements) and displays it on a
suitable screen (for example the one linked to the pen, or one in the
vicinity). The authors propose several interesting applications, and
the idea seems at least practically feasible.
Estrogen and memory
Hormones and Behavior 34 had a lot of articles of Estrogen effects on
memory. Yummy for neuromodulation hackers like me!
Posttraining estrogen and memory modulation
M. G. Packard, Horm Behav 34:2, 126-39 oct 1998
A review of the effect of injections of estradiol after a training
event in rats, and how this interacts with acetylcholine in memory
modulation. Ovariectomized (lacking ovaries) rats that got estradiol
had better retention of a water maze than rats that got placebo, if
the injection was done immediately after the training but not two
hours later. It turns out that acetylcholine antagonists counteract
this effect, which suggests ACh interacts with estradiol in enhancing
memory. Good news for ovariectomized rats.
Effects of estrogen replacement therapy on PET cerebral blood flow and
neuropsychological performance
S. M. Resnick, P. M. Maki, S. Golski, M. A. Kraut, A. B. Zonderman
Horm Behav 34:2, 171-82 oct 1998
There are also reports that estrogen might protect against age-related
memory loss or Alzheimer's Disease. In this study, linked to the
Baltimore Longitudinal Study of Aging, they did PET scans and
assessments of people 55 years old or older. They tested verbal and
visual delayed recognition memory, and compared women receiving
estrogen with untreated women of the same age. There were no obvious
anatomical differences, but in memory processing there were
significant differences in regional blood flow in brain areas likely
related to memory, and the treated women did better on the memory
tests. Good news for older women.
Estrogen and memory in a transsexual population
C. Miles, R. Green, G. Sanders and M. Hines
Horm Behav, 34:2 199-208 oct 1998
What about estrogen effects in men? For obvious reasons nobody has
tried it, but here is a study that exploits one rare window of
opportunity: male->female transsexuals awaiting gender reassignment
surgery and receiving hormone treatment. Treated persons scored higher
on paired associate learning than an untreated transsexual control
group, but not on digit span tests (working memory) or other cognitive
tasks. It seems that estrogen has the same verbal memory enhancing
effects in men as in women. Good news for transsexual men.
Nanotechnology
Architectural Considerations for Self-Replicating Manufacturing Systems
J. Storrs Hall, 6th Foresight Conference on Molecular Nanotechnology
http://www.foresight.org/Conferences/MNT6/Papers/Hall/index.html
A discussion about how to use self-replicating nanotech in an
efficient manner; it turns out that it is not optimal to have a
replicator replicate too many or too few generations when
nanofacturing a macroscopic object (the optimum seems to be to divert
them when their mass equals 69% of the size of the task to be
done). In the same manner there might be an optimal complexity: very
complex replicators replicate slower than a manufacturing system of
simpler units. There is also a discussion of the bootstrapping process
from a single seed to a nanofacturing system; you start with a complex
replicator that builds successive generations of devices, each
generation with more kinds but simpler units.
Philosophy of information and evolution
Information, evolution and "error-friendliness" Ernst Ulrich von
Weizäcker, Christine von Weizäcker, Biological Cybernetics 79 501-506
1998
Information is a rather confused concept in modern science; the
Shannon information is for example sometimes equated with entropy,
sometimes to negentropy, the entropy with a negated sign; the results
are often that systems we view as having much or little information
according to theory has the opposite (white noise is very energy rich,
in classical information theory). What the authors suggest as a better
model for speaking about information based on two components, novelty
and confirmation. Novelty represents the surprise we get from a
message, and is quite close to the Shannon idea. Confirmation is more
abstract, and represents the stabilizing factors that give the message
a meaning: the channel it is transmitted through, the code, the
knowledge of the receiver (this is what Shannon took for granted). If
novelty or confirmation is zero, the information is zero. They then go
on to apply this to discuss information in biology, evolution and
human action. The problem is to create error-friendliness: errors
produce novelty, and we need confirmation to make use of it. The
article is rather philosophical and a bit rambling, but good food for
thought.
Physics of Information
Energy cost of information transmission
Lev B. Levitin, Physica D 120 (1998) 162-167
There is a minimum energy required to transmit a unit of information
over a noisy channel equal to kT. This is the latest response in a
series of papers about the energy costs of communication, apparently
contradicting Landauer's claim that information transmission doesn't
have to be dissipative. What really happens is that if you ignore
noise you set the temperature to zero, and then there is no real
cost. But otherwise, you have to dissipate some energy.
The maximum speed of dynamical evolution
Norman Margolus and Lev B. Levitin Physica D 120 (1998) 188-195
A discussion of how quickly an isolated system can pass through
distinct states; they derive a bound 2E/h of the rate based on E-E0,
the systems average energy minus the ground state energy. This shows
that 1J of energy cannot increase a computer's processing rate by more
than 3*10^33 operations per second.
Bad news for jupiter brain designers :-)
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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