From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Jan 08 1999 - 08:53:09 MST
This time, a mixed bouquet of phramacology, psychoepidemology, EEG,
computer graphics, anthrocomology and a few twigs of particle physics:
Sneaking neuroprotectants through the blood-brain barrier
Social class in childhood affecting health in adulthood
Brain-wave recognition of sentences
Modelling of plant ecosystems
A virtual-reality interface for a scanning tunneling microscope
Is the strong anthropic principle too weak?
Decay of protons and neutrons induced by acceleration
Neuroprotection with noninvasive neurotrophin delivery to the brain
Dafang Wu and William M. Pardridge Proceedings of the National Academy
of Sciences USA, Vol 96 254-259 January 1999
Neutrotrophic factors are known to have neuroptrotective properties,
and might be candidates both for treating ischemia and dementias (as
well as nerve damage). Unfortunately they have to be injected
intraventricularly to have any effect, since they do not cross the
blood brain barrier. Wu and Pardridge manage to sneak BDNF into the
brain anyway, by polyglycosylating the protein so that it isn't
absorbed by the peripheral tissues, linking it with another protein so
that it is actively transported through the barrier and adding biotin
which seems to enhance the process. They tested this on rats, and the
treatment (given intravenously for two weeks after ischemic damage to
the brain) managed to keep the number of neurons in the CA1 region
near normal. Very nice, and the possibility of "smuggling" other drugs
into the brain is promising.
Social class in childhood and general health in adulthood:
questionnaire study of contribution of psychological attributes
Hans Bosma, H Dike van de Mheen and Johan P Mackenbach, British
Medical Journal 2 January 1999, 318 18--22
http://www.bmj.com/cgi/content/abstract/318/7175/18
A tricky but interesting subject: how does social class affect
attitudes and health? The article suggests that childhood social class
affects health more than adult social class. Adverse personality
profiles such as external locus of control, neuroticism, parochialism,
lack of future orientation and negative coping styles are more common
for people who grew up with a low childhood social class, and they
might make people more susceptible to illness; this seems to account
for half of the association low social class and bad health. These
results seems to suggest that the memes you acquire as young might
actually have health effects later in life. Yet another reason to
spread dynamical optimism, and especially among the young.
Brain-wave recognition of sentences
P. Suppes, B. Han and Z. L. Lu
Proc Natl Acad Sci U S A, 95:26 15861--6 Dec 22 1998
It seems that it is possible to at least partially detect the
brainwave patterns of words and sentences a subject hears. The authors
measured the electrical and magnetic brain waves from two subjects
hearing 12 test sentences (of the type Subject-verb-object; "Bill
loves Susan", "Mary sees John", ...) a number of times, and then used
averaging to create prototypes that were in turn fourier transformed,
filtered and inverse transformed into filters. Recognition rates
varied a lot, but the average recognition was around 40-50% (the best
was 86.7%). Electrode location, the use of bipolar electrodes and
various transforms of the data improved recognition. They tried to
paste together the EEG of individual words, in order to see if one
word has a standardized EEG representation or if it changes depending
on its position in the sentence; it turned out that recognition was
still possible. Overall, this paper shows some interesting
possibilities for us interested in EEG-interface, but it is clear that
a practical interface might be rather tricky.
Realistic modeling and rendering of plant ecosystems
Oliver Deussen, Pat Hanrahan, Bernd Lintermann, Radomír Měch,
Matt Pharr, Przemyslaw Prusinkiewicz
SIGGRAPH '98. Proceedings of the conference on Computer Graphics, pages 275-286
http://www.acm.org/pubs/citations/proceedings/graph/280814/p275-deussen/
A lovely paper about how to model a realistic plant ecosystem. They
start with setting up a terrain model, both interactively and with
pseudorandom features. Then they calculate the amount of water in the
soil in different regions, since this affects what plants will
grow. Then they "seed" different species (again, partially
interactive, partially random) and let them grow according to a
competition model (self-thinning: if two plants get too close
together, the weaker will die and vanish; since the strength of plants
depends on the environment the model naturally makes plants grow at
the "right" places). Then the plants themselves are modelled as
L-systems, and some simplifications in order to keep the specification
files manageable (without them the specification files would be
several hundred gigabytes!). The results are wonderfully realistic.
Transhuman relevance? I don't know, but it is a lovely paper and
beautiful graphics. Well worth remembering when we as uploads want to
take on gardening :-)
The nanomanipulator: a virtual-reality interface for a scanning
tunneling microscope
Russell M. Taylor, Warren Robinett, Vernon L. Chi, Frederick P., J
r. Brooks, William V. Wright, R. Stanley Williams, Erik J. Snyder
SIGGRAPH '93. Proceedings of the 20th annual conference on Computer
graphics, pages 127-134
http://www.acm.org/pubs/citations/proceedings/graph/166117/p127-taylor/
A head-mounted display and force-feedback manipulator arm connected to
a STM - nice! The user can view the surface and move around on it,
feel it and modify it. Maybe not really useful yet other than
interactive exploration, but it definitely sounds like a tool that
will be used when nanotech gets truly underway.
Is the Strong Anthropic Principle Too Weak?
A.Feoli, S.Rampone
to appear in Il Nuovo Cimento B
http://xxx.lanl.gov/abs/gr-qc/9812093
Something for the discussions about the Great Filter, I suppose; I'm
personally not that fond of this realm. The authors revisit Carter's
formula for the expected time between the emergence of intelligent
life and the end of the biosphere (either interpreted as "we're very
unlikely and the biosphere will soon vanish!" if you assume many
unlikely steps in our ontogenesis, or "we're surprisingly likely!" if
you start from the estimated lifetime of the biosphere). They show
that if the steps are not independent but chained the formula gives an
overestimate of the time. In addition, if you assume a large universe
with many planets where life can develop, the number of improbable
steps in our evolution is balancee large number of planets producing a
longer time between the emergence of intelligence and the end of its
biosphere, and this grows with the number of terrestrial planets in
the Universe. In the end they propose a stronger form of the Strong
Anthropic Principle, the Mediocrity Anthropic Principle: "The Universe
(and hence both the fundamental parameters on which it depends, and
the amount of places where the evolitoon can take place9 must be such
as to admit the creation of observers on some stage, and to assure
them a not trivial living time". Well, we have the WAP, SAP, FAP and
now the MAP.
Decay of protons and neutrons induced by acceleration
George E.A. Matsas, Daniel A.T. Vanzella
http://xxx.lanl.gov/abs/gr-qc/9901008
Apparently accelerations can help induce proton decay in the standard
model; the authors calculate that for accelerations around 11MeV (I'm
not sure how they convert energy into acceleration) the proton
lifetime becomes roughly equal to the neutron lifetime. Maybe useful
for matter conversion.
-- ----------------------------------------------------------------------- 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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