From: Anders Sandberg (asa@nada.kth.se)
Date: Thu Jul 17 2003 - 08:47:25 MDT
Some fun papers:
How the interplay between water competition and pests help stabilize
Balinese Rice farming in a distributed manner.
DNA microarray studies of the DAF-16 pathway of ageing in C elegans
Age-related learning deficits and brain oxidative stress ameliorated by
superoxide dismutase/catalase mimetics
Nature also has an editorial (Nature 424, 237 (17 July 2003);
doi:10.1038/424237a, Don't believe the hype ) and a news feature (Nature
424, 246 - 248 (17 July 2003); doi:10.1038/424246a Nanotechnology: A
little knowledge... ) on nanotech resistance.
http://www.santafe.edu/sfi/publications/wpabstract/200305030
SFI Working Paper Abstract 2003
Cooperation in Balinese Rice Farming
Author(s): J. Stephen Lansing and John H. Miller
Paper #: 03-05-030
Abstract:
For centuries Balinese rice farmers have been engaged in cooperative
agricultural practices. Without centralized control, farmers have
created a carefully coordinated system that allows productive farming in
an ecosystem that is rife with water scarcity and the threat of disease
and pests. We develop a simple game-theoretic model, inspired by a
generation of careful anthropological field work, to provide a compact
explanation for many of the most salient features observed in the
system. We find that while externalities caused by either water scarcity
or pests would, in isolation, be expected to cause a serious failure in
the system, the ecology of the rice farming system links these two
externalities in such a way that cooperation, rather than chaos,
results. We test key features of the model through both natural and
computational experiments and a field survey focused on the strategic
motivations of the farmers.
Nature 424, 277 - 283 (17 July 2003); doi:10.1038/nature01789
Genes that act downstream of DAF-16 to influence the lifespan of
Caenorhabditis elegans
COLEEN T. MURPHY*, STEVEN A. MCCARROLL?, CORNELIA I. BARGMANN?, ANDREW
FRASER?, RAVI S. KAMATH?, JULIE AHRINGER?, HAO LI* & CYNTHIA KENYON*
Ageing is a fundamental, unsolved mystery in biology. DAF-16, a
FOXO-family transcription factor, influences the rate of ageing of
Caenorhabditis elegans in response to insulin/insulin-like growth factor
1 (IGF-I) signalling. Using DNA microarray analysis, we have found that
DAF-16 affects expression of a set of genes during early adulthood, the
time at which this pathway is known to control ageing. Here we find that
many of these genes influence the ageing process. The insulin/IGF-I
pathway functions cell non-autonomously to regulate lifespan, and our
findings suggest that it signals other cells, at least in part, by
feedback regulation of an insulin/IGF-I homologue. Furthermore, our
findings suggest that the insulin/IGF-I pathway ultimately exerts its
effect on lifespan by upregulating a wide variety of genes, including
cellular stress-response, antimicrobial and metabolic genes, and by
downregulating specific life-shortening genes.
PNAS | July 8, 2003 | vol. 100 | no. 14 | 8526-8531
Reversal of age-related learning deficits and brain oxidative stress in
mice with superoxide dismutase/catalase mimetics
Ruolan Liu *, Ingrid Y. Liu *, Xiaoning Bi , Richard F. Thompson *,
Susan R. Doctrow , Bernard Malfroy and Michel Baudry *
Oxidative stress has been implicated in cognitive impairment in both old
experimental animals and aged humans. This implication has led to the
notion that antioxidant defense mechanisms in the brain are not
sufficient to prevent age-related increase in oxidative damage and that
dietary intake of a variety of antioxidants might be beneficial for
preserving brain function. Here we report a dramatic loss of learning
and memory function from 8 to 11 months of age in mice, associated with
marked increases in several markers of brain oxidative stress. Chronic
systemic administration of two synthetic catalytic scavengers of
reactive oxygen species, Eukarion experimental compounds EUK-189 and
EUK-207, from 8 to 11 months almost completely reversed cognitive
deficits and increase in oxidative stress taking place during this time
period in brain. In particular, increase in protein oxidation was
completely prevented, whereas increase in lipid peroxidation was
decreased by 50%. In addition, we observed a significant negative
correlation between contextual fear learning and levels of protein
oxidation in brain. These results further support the role of reactive
oxygen species in age-related learning impairment and suggest potential
clinical applications for synthetic catalytic scavengers of reactive
oxygen species.
-- ----------------------------------------------------------------------- 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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