From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Nov 13 1998 - 17:43:25 MST
(am I crossoposting this too widely?)
Extending the lifespan of flies
Working memory constrains the prisoners' dilemma
Communication can lead to cooperation in the single-shot prisoner's dilemma
Neutrino propulsion
A pheromone guided robot
PAF, Estrogen and AF-DX 116 improve memory
Genetics
Extended life-span and stress resistance in the drosophila mutant
methuselah, Y. J. Lin and L. Seroude and S. Benzer, Science 282:5390,
943--6.
That selective breeding and genetic modifications can make C elegans
and Drosophilia live longer is old news; this article is interesting
because it identifies a single gene change that increases lifespan with
35%. This gene, mth, seems to be some kind of G protein coupled
receptor. Experiments show that methuselah flies can withstand stress
better than normal flies, both in the form of starvation, free
radicals and high temperature. This seems to fit in with what has been
observed in C elegans mutants. Overall, this article suggests that
aging may be linked to stress resistance, and that even single genes
can improve lifespan.
Theory of Cooperation
Working memory constrains human cooperation in the Prisoner's Dilemma,
Manfred Milinski and Claus Wedekind, Proc. Natl. Acad. Sci. USA, 1998,
95, 13755-13758
http://www.pnas.org/cgi/content/abstract/95/23/13755
An empirical experiment studying what strategies people use in the IPD
when their memory is limited by a distraction task. As the memory load
increases, the subjects tended to shift from pavlovian strategies
("win-stay, lose-shift") towards Tit for Tat; this fits quite well
what has been observed in simulations.
Communication and Cooperation, John H. Miller, Carter Butts, and David
Rode (Submitted to J. Games and Economic Behavior)
http://www.santafe.edu/sfi/publications/Abstracts/98-04-037abs.html
Traditional wisdom says that in a single-shot prisoners' dilemma it is
rational to defect, and that cooperation will not emerge. However, if
the agents can communicate with each other and evolve, then brief
bursts of cooperation can emerge even if they play single-shot PD with
each other. These bursts seems to involve the emergence of more
complex communication which is used to "make deals".
Physics / Spaceflight
Neutrino Propulsion for Interstellar Spacecraft, J. A. Morgan
http://xxx.lanl.gov/abs/physics/9811009
Another fun kind of propulsion; by exploiting parity violation in weak
interactions it is possible to create anisotropic neutrino emissions,
which would allow rest mass directly to impulse. The whole system
looks rather unwieldy (involving slowing down and polarizing muons,
using antimuons to make neutrons to regenerate target nuclei etc), but
the concept is fun.
Robotics
A Pheromone-Guided Mobile Robot that Behaves like a Silkworm Moth with
Living Antennae as Pheromone Sensors, Yoshihiko Kuwana and Isao
Shimoyama, International Journal of Robotics Research vol 17 no 9
Steptember 1998 pp 924--933
A small robot is controlled by signals from moth antennae fed through
a very simple neural network, making it able to seek out pheromone
sources.
Nootropics
Effects of posttraining intrahippocampal injections of platelet-
activating factor and PAF antagonists on memory, L. A. Teather,
M. G. Packard and N. G. Bazan, Neurobiol Learn Mem, 70:3 349-63, nov
1998
Platelet Activating Factor injected in the hippocampus has been shown
to improve memory (Izquierdo95); this paper shows both this effect
(and that a structurally similar derivative has no effect) and that
PAF antagonists impair memory. PAF only acts if injected close to the
training, 2 hours later it has no effect. This seems to suggest that
PAF plays a role in the hippocampal memory consolidation process.
Estrogen improves performance of reinforced T-maze alternation and
prevents the amnestic effects of scopolamine administered systemically
or intrahippocampally, A. J. Fader, A. W. Hendricson and
G. P. Dohanich, Neurobiol Learn Mem, 69:3, 225-40 may 1998
Estrogen seems also to have memory improving effects, at least when
given to ovariectomized rats. It also can protect against the effects
of scopolamine.
AF-DX 116, a presynaptic muscarinic receptor antagonist, potentiates
the effects of glucose and reverses the effects of insulin on memory,
S. R. Kopf, M. M. Boccia and C. M. Baratti, Neurobiol Learn Mem, 70:3,
305-13, nov 1998
Glucose improves memory , and AF-DX 116 seems to enhance the effect of
it. The drug seems to be a blocker for autoreceptors inhibiting the
release of acetylcholine, so it is possible that it acts by making the
release of Ach (increased by the glucose) even higher. [This is an
interesting possibilitiy for a long-lasting nootropic rather than one
that must be used in conjunction with what is learned. ]
Yes, it seems like there are lots of ways of improving memory
chemically; but deep down they might all be related or a few basic
pathways.
-- ----------------------------------------------------------------------- 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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