What Is A Moment? "Cortical" Sensory Integration Over A Brief Interval, PNAS 
Abstract: Recognition of complex
temporal sequences is a general sensory problem that requires
integration of information over time. We describe a very simple
"organism" that performs this task, exemplified here by
recognition of spoken monosyllables. The network's computation can
be understood through the application of simple but generally
unexploited principles describing neural activity. The organism is
a network of very simple neurons and synapses; the experiments are
simulations. The network's recognition capabilities are robust to
variations across speakers, simple masking noises, and large
variations in system parameters. The network principles underlying
recognition of short temporal sequences are applied here to
speech, but similar ideas can be applied to aspects of vision,
touch, and olfaction. In this article, we describe only properties
of the system that could be measured if it were a real biological
organism. We delay publication of the principles behind the
network's operation as an intellectual challenge: the essential
principles of operation can be deduced based on the experimental
results presented here alone. An interactive
web site is available to allow readers to design and
carry out their own experiments on the organism.
AI and Simulation--Modeling the Emergence of Cooperation & Trust, Simulation
Excerpts: "Last month 's column gave an
historical perspective on the modeling and simulation of business
and industrial firms. It ended with the suggestion that the next
stage in these modeling efforts would require better ways to
account for the human aspects of the countless interactions that
take place continually within and among today 's enterprises.
Optimal management of financial and physical resources hinges
finally on the successful management of people. Perhaps the most
important issue in business management is finding just the right
balance between competition and cooperation within the manager 's
own company as well as between that company and other companies.
The firm is a network of its employees and its internal
organizations. It lives in a greater network of markets,
suppliers, customers, partners and competitors. Using agents is a
natural way to model networks but most of the existing agent-based
simulations employ homogeneous agents. The research reviewed above
implies that a model of a firm as a network would only be
interesting if the agents were heterogeneous enough to produce a
heterarchy at the same time as they evolved toward cooperation
through the action of strong reciprocity. This research into
cooperation, competition, diversity and learning in organizations
only suggests some of the problems that are still to be addressed
in order to build practical simulations that will actually help
the managers of real-world enterprises. (...)
Cosmides and Tooby are Co-directors of the Center for
Evolutionary Psychology at the University of California,Santa
Barbara.For a look at their more current research,see
http://www.psych.ucsb.edu/research/cep
. Published papers by Samuel Bowles,Herbert Gintis and their
colleagues may best be found starting from Bowles ' Website at
http:://www-unix.oit.umass.edu/~bowles/.Some
of their as yet unpublished working papers are available from the
Santa Fe Institute at http://www.santafe.edu/sfi/publications/00wplist.html
.For more about heterarchy and David Stark 's research,see
http://www.sociology.columbia.edu/faculty/stark/.
The following Websites also contain information pertinent to
enterprise modeling as discussed in this and last month 's
columns:
Cultural Revolution In Whale Songs, Nature
About thirty years ago it was recognized that
Humpback whales are capable of elaborate songs lasting more than
fifteen minutes, about five times longer than songs that humans
remember to sing. Since then a number of researchers have tried to
understand why they are doing this over and over again for a
number of months during breeding season. During that time the
songs -organized in well reproducible phrases and themes that even
seem to "rhyme"- slowly evolve in a manner similar to human songs:
variations are introduced, some phrases are shortened and dropped,
new ones introduced etc. For the rest of the year, whales are
manly busy traveling to the high latitude feeding grounds
apparently forgetting about the songs. But once they are back in
the breeding grounds the singers all start singing again the same
songs right where they left them at the end of the previous
season. Because of the temporal coincidence of breeding and
singing it was speculated that females are attracted to the best
singers. Careful experiments using playback of the latest songs
showed, however, that instead of flocking around the singers the
females rather avoid them and take off with the non-singing jocks
among the whales. Are the songs perhaps some form of Humpback
Whale Blues?
Other speculations that songs are used as some sort long-range
sonar used by males to locate other whales is even less founded by
empirical evidence. While blue whales produce low frequency sounds
that can be heard over long distances humpback whales don't seem
to make any effort to be heard over long ranges by for instance
singing at a depth that is optimized for underwater sound
propagation.
Just like human music does not give a direct evolutionary
advantage to the singer but is rather an expression of culture,
Rendell & Whitehead have argued that humpback whale songs are
an expression of whale culture and transmitted by social learning.
Independently Noad et al came to the same conclusion in a striking
observation as a result of listening to more than a thousand hours
of humpback whale songs: They found evidence for a "cultural
revolution" in musical style. Within a few years all singers on
the East coast of Australia picked up a song imported by two
initial traveling minstrel singers from the West coast. The
radical difference between the two styles is evident even to the
non-expert. Michael Noad was kind enough to make a sound example,
illustrating the difference, available to ComDig. Click here
to listen to the sound example. It is a
"(...) phrase from the first theme of the old and
new songs of our study (you can see where one stops and the
other starts by the difference in the background noise levels
as well as the sounds being obviously different). The old song
is simply a series of five 'down-up moans', the new phrase is a
'long descending moan' and a 'level growl'." (M.
Noad)
This rapid spread among the whole population cannot be
explained without the presence of cultural transmission. In a
complex systems framework this phenomenon could be understood as a
consequence of a "small world" network structure among the
humpback whale singers (see Mayer-Kress
& Porter).
- Cultural
Revolution In Whale
Songs, Michael J. Noad,
D.H. Cato, M. M. Bryden, M-N. Jenner, K. Curt, S.
Jenner, Nature, Vol 408,11/30/00
- Whales
Can Learn New Songs When It Comes to Tunes, Whales Can
Be Teenyboppers, Keay
Davidson, San Francisco Chronicle,
11/30/00
- Culture
In Whales And Dolphins,
Complexity
Digest 2000.41.1
- Remarks
On Whale Cultures From A Complex Systems
Perspective, G.
Mayer-Kress, M.A. Porter, Commentary On Rendell, L.
& Whitehead, H. (2001) Culture
in whales and dolphins,
Behavioral and Brain Sciences 24 (2)
Beyond Game Theory, WorldLink
While game theory works well for simple zero-sum
situations, its powerful extension, the theory of moves, can offer
valuable insights into the dynamic nature of conflicts.
If it really is your friend's birthday, then buying the
expensive seats will go down better than just an evening at the
bar.
But if it's not his birthday, then while your friend will be
delighted with the unexpected treat, your bank manager might not
be.
And on the face of it, this is also what happened in the
Cuban missile crisis, where the thermonuclear equivalent of
driving over the edge forced both sides into a draw.
And the answer emerging from his research takes the form of
a powerful extension of game theory, now attracting much interest
among experts in conflict resolution.
As its name suggests, ToM allows the reactions of players to
evolving situations to be traced in detail.
In a series of intriguing papers, Brams and his co-workers
have used ToM to analyse a whole raft of conflicts, from
game-theoretic classics like the Cuban missile crisis to complex
battles of will such as that between the Polish Communist party
and the trade union movement Solidarity in the early
1980s.
Seen from the standpoint of standard game theory, the
response of the Nixon administration to the outbreak of the
conflict was terrifyingly reckless.
But what the White House chose to do shocked many: it upped
the stakes, putting all US military forces on global nuclear
alert.
According to Brams, the reason lies in the way the conflict
evolves into different states, according to the starting positions
of the players - a feature better captured by ToM than by standard
game theory.
At root, this long-running conflict is between the Irish
Republican Army (IRA) - determined to make Northern Ireland part
of the Irish republic - and the British government and Ulster
Unionists, who are determined to see the province remain in the
UK.
So why did the British government agree in 1998 to the
power-sharing accord of the Good Friday agreement, when the IRA
had already called a cease-fire?
Summarized with Copernic
Summarizer
Chaos Theory Tells Pilots When To Take A Break, New Scientist
Excerpt: "Airline pilots and air traffic
controllers who are too tired to work safely could soon be
identified automatically, thanks to a Japanese monitoring system
that analyses voice patterns for signs of fatigue.
"Our system is able to detect tiredness in test subjects 10
to 20 minutes before the subjects themselves notice it," says
Kakuichi Shiomi, chief researcher at the Electronic Navigation
Research Institute near Tokyo, which developed the system.
Human error currently accounts for around 80 per cent of all
air accidents worldwide. "Crew fatigue is a very real problem,
especially on long-haul flights crossing many time zones," says
Shiomi.
Called a fatigue and drowsiness predictor, the system uses
the mathematics of chaos theory to compare changes in the voices
of wide-awake, alert people with those of fatigued people. The
change is known to be related to a drop in blood pressure when
people are tired--but it is very subtle. So Shiomi's team at ENRI,
a division of the Japanese Ministry of Transport, had to come up
with a way of analysing speech that brings these small changes
into sharp relief."
Gamma Oscillations and Object Processing in the Infant Brain, Science
Abstract: An enduring controversy in neuroscience
concerns how the brain "binds" together separately coded stimulus
features to form unitary representations of objects. Recent
evidence has indicated a close link between this binding process
and 40-hertz (gamma-band) oscillations generated by localized
neural circuits. In a separate line of research, the ability of
young infants to perceive objects as unitary and bounded has
become a central focus for debates about the mechanisms of
perceptual development. Here we demonstrate that binding-related
40-hertz oscillations are evident in the infant brain around 8
months of age, which is the same age at which behavioral and
event-related potential evidence indicates the onset of perceptual
binding of spatially separated static visual features.
Novel Vaccine Protects Monkeys From Ebola Infection, NIAID/Science Daily
Excerpts: Few viruses are more feared than Ebola
virus, the deadly microbe that periodically attacks African
villages and kills up to 90 percent of those it infects. Although
other viral diseases claim more lives each year, the ruthless
efficiency and nightmarish symptoms of Ebola virus make a vaccine
against this killer an important goal of scientists. Now, as
described in the November 30 issue of Nature, a team of
researchers led by scientists from the National Institutes of
Health (NIH) has developed a novel vaccine that prevents Ebola
virus infection in monkeys. All four vaccinated monkeys were
completely protected from a lethal dose of the virus. This study
describes the first primate model of immune protection against
Ebola virus, a model that may allow scientists to rationally
design a vaccine that prevents this dreaded disease in humans.
"Doctors have essentially been helpless against Ebola
virus," says Gary Nabel, M.D., Ph.D., director of the Dale and
Betty Bumpers Vaccine Research Center (VRC) at the NIH and a lead
author of the study. "We have not known if immunity to the virus
exists or what parts of the immune response are important. Our
studies show that animals can launch an effective immune response
against Ebola virus, and we can use knowledge of this response to
design a vaccine that protects non-human primates from infection.
Although much more work needs to be done, we hope this moves us
closer to new vaccines and treatments for Ebola and other
viruses."
Ebola virus kills quickly, giving the body little time to
launch an effective immune response. Infected individuals suffer
severe pain, high fever and extensive internal bleeding. Although
the virus periodically strikes humans, scientists do not know
where it resides in nature between outbreaks. (…)
Dr. Nabel and colleagues had previously tested genetic Ebola
vaccines-strands of DNA containing genes that encode Ebola virus
proteins-for their ability to induce immune responses in rodents
and to protect against disease. Unlike traditional vaccines,
typically made from viral proteins, DNA vaccines more closely
mimic virus infection because they enter a cell and use that
cell's machinery to manufacture new viral proteins. Researchers
believe this strategy might better trick the immune system into
thinking a real virus infection has occurred. (…)
Armed with this promising new vaccine, the researchers
tested a novel prime-boost immunization strategy on eight monkeys.
Four monkeys received the three-strain Ebola virus DNA vaccine and
then were injected with the Ebola-adenovirus booster. The other
four monkeys received placebo immunizations. All four vaccinated
monkeys launched strong anti-Ebola immune responses and survived a
subsequent exposure to lethal doses of Ebola Zaire virus. Three of
these monkeys showed no sign of viral infection, whereas a slight,
temporary increase in Ebola virus in the blood of one of the
vaccinated monkeys disappeared after one week. More than six
months after infection, the four monkeys remained symptom-free
with no detectable virus in the blood.
The researchers are continuing their efforts. "We of course
want to test the multivalent vaccine for effectiveness against all
three strains of Ebola virus," says Dr. Sullivan, "but we also
need to look more closely at the immune response induced by these
vaccines so we can nail down what is needed for protection." By
studying the mechanism of protection induced by the vaccine, they
can determine what combination of antibodies, helper T cells and
killer T cells defend the monkeys against infection. They then
hope to use this information to rationally design new vaccines and
antiviral treatments for humans.
-
Excerpts: If a person's immune system
successfully fights off an infection, not only does that person
recover, but they also acquire immunity against re-infection by
that same pathogen. The ability of the immune system to remember
pathogens it has already defeated, and to respond rapidly and
effectively to them during future exposures, is the basis of
vaccination strategies. (…)
"It was thought that the only role for these molecules was
to enable T cells to directly or indirectly destroy infected
cells," Harty said. "We have identified another role for the
molecules, as regulators that control how many T cells are
generated in response to infection and how many of these cells
survive and contribute to immune memory."
Harty added that this work reinforces a long-standing notion
about the immune system, that it is able to use the same molecule
for different functions.
"The immune system has learned to use and modify existing
systems to do the jobs required to fight off infections," Harty
said. (…)
Until very recently, researchers evaluating the nature and
strength of an immune response focused on antibody production.
Antibodies are molecules generated by the immune system to help
fight infection. They are easy to detect and quantify. In the last
five years, however, there has been a revolution in scientists'
ability to identify, count and assess the function of
antigen-specific T cells with high precision. Measuring these
cells gives a much more accurate assessment of an immune response
to either an infection or a vaccine.
"I suspect that in the next few years we will be able to use
these tools to assess how good human vaccines actually are," Harty
said.
In the current studies, Harty and his colleagues used these
measuring techniques and previous research to set about carefully
measuring the levels of T cells during different stages of
infection. Investigating the immune response in mice, genetically
engineered to lack either or both molecules, the researchers
elucidated the regulatory roles of perforin and interferon gamma.
The mice were infected with Listeria monocytogenes, a
bacterial pathogen that causes food-borne infections in humans.
The studies showed that perforin controls the total number of T
cells initially generated in response to a pathogen, and
interferon gamma controls the process by which most of those cells
are eliminated after the infection is cleared. Interferon gamma
also affects which parts of the pathogen cause the immune system
to respond.
The roles of these molecules did not change when the
researchers repeated the experiments using a virus as the
infecting agent even though viruses and bacteria interact with the
host animal in very different ways during an infection.
"This is very basic research aimed at understanding how this
very precisely orchestrated expansion and decline, and memory
phase of the immune system is controlled," Harty said.
"Understanding how the basic biology of the system is regulated
provides insight into how we might manipulate the system. In the
case of these studies, the ultimate goal would be to learn how to
manipulate the levels of T cell memory, which could result in
better, more effective vaccinations."
Autoimmune diseases result from inappropriate activation of
certain T cell subsets, which recognize self-antigens as opposed
to pathogen antigens. Understanding how T cells are regulated
could also help scientists understand and possibly treat
autoimmune conditions.
Close Encounters: Good, Bad, and Ugly, Science
Summary: Microbiologists often focus on one
organism and its relationship to its host at one point in time.
But viewed in light of evolution, host-parasite relationships
range from deadly to helpful, depending on the communication
between them. At a meeting here last month of virologists,
bacteriologists, parasitologists, and molecular biologists--each
dealing with different microorganisms in distinct
ways--researchers lamented that evolution is often considered
outside the bailiwick of microbiologists, particularly those
studying infectious diseases.
Copernic Summary: As an unlikely mix of virologists,
bacteriologists, parasitologists, and molecular biologists--each
dealing with different microorganisms in distinct ways--discussed
their work, they came to better appreciate evolutionary biologist
Theodosius Dobzhansky's observation that nothing makes sense
except in the light of evolution.
But stepping back to view the whole range of relationships
between microbes and their hosts reveals that "there's a spectrum
[of microorganisms] from the highly virulent to barely
pathogenic," says Stephen Beverley, a molecular parasitologist at
Washington University in St. Louis.
Stanford University molecular biologist Sharon Long has been
exploring a cooperative interaction that might once have been an
adversarial one: the symbiosis between a plant and its
nitrogen-fixing bacteria.
As the plant becomes an ally in promoting this infection, it
builds a tunnel of extracellular material around the dividing
bacteria and allows them entry into some of its cells.
Take Leishmania, a protozoan parasite that now infects some
12 million people worldwide, often causing disfiguring disease and
sometimes death.
Complexity and Fragility in Ecological Networks, SFI Working Papers
Abstract: A detailed analysis of three
species-rich ecosystem food webs has shown that they display
scale-free distributions of connections. Such graphs of
interaction are in fact shared by a number of biological and
technological networks, which have been shown to display a very
high homeostasis against random removals of nodes. Here we analyze
the response of these ecological graphs to both random and
selective perturbations (directed to most connected species). Our
results suggest that ecological networks are extremely robust
against random removal but very fragile when selective attacks are
used. These observations can have important consequences for
bio-diversity dynamics and conservation issues, current
estimations of extinction rates and the relevance and definition
of keystone species.
Ancient South African Soils Point To Early Terrestrial Life, Science Daily
Excerpts: "Remnants of organic matter in ancient
soil more than 2.6 billion years old may be the earliest known
evidence for terrestrial life, according to a team of Penn State
astrobiologists.
"Our work shows that the organic matter in this soil very
probably represents remnants of microbial mats that developed on
the soil surface between 2.6 and 2.7 billion years ago," says Dr.
Hiroshi Ohmoto, professor of geochemistry and director of The Penn
State Astrobiology Center. "This places the development of
terrestrial biomass more than 1.4 billion years earlier than
previously reported." Evidence that microorganisms flourished in
the oceans since at least 3.8 billion years ago exists, but when
these microorganisms colonized on land is not clear. The oldest
undisputed remnants of terrestrial biomass have been 1.2
billion-year-old microfossils found in Arizona.
Examining samples taken from Mpumalanga Province, South
Africa, using a variety of geochemical methods, the researchers
report in this week's issue of Nature, that a paleosol dating to
between 2.6 and 2.7 billion years ago contains organic carbon that
was neither created by high temperature fluids nor is the remnant
of later petroleum migration, but is in-situ biological in origin.
(…)
In the lower portion of the paleosol, things are less clear
because the effects of seeping water and the dissolution and
precipitation of materials suggest some decomposition. While
identifying the organism in the microbial mats is difficult, the
researchers are certain that they were not photosynthetic sulfur
bacteria as there is no sulfur present. Photosynthetic blue-green
algae, however, are a likely possibility for the mat formation
because the ancient remnants have nearly identical carbon isotope
ratios as modern blue-green algal mats in fresh water.
The researchers are also certain that the mats formed on
land, not in the oceans, because the carbon isotope values for the
carbon in the paleosol are distinctly different from the organic
carbon found in marine sedimentary rock.
"Although terrestrial bacterial communities were predicted
by previous researchers, this is, to our knowledge, the first
study presenting several lines of evidence for an extensive
development of microbial mats on soil surfaces in the Archaean,"
says Ohmoto. "Our finding may then imply that an ozone shield
developed before 2.6 billion years ago.
"The ozone shield would have protected land-based biological
forms from the effects of cosmic radiation. Development of the
ozone shield requires an oxygen-rich atmosphere. Our finding of
ancient biomats on land is an important addition to a growing line
of evidence suggesting that the rise of atmopsheric oxygen took
place more than 2.6 billion years ago." "
Climate Science "In Play", UNFCCC
Summary: Without action to limit greenhouse gas emissions
the Earth’s climate will warm at a rate unprecedented in the
last 10,000 years: If actions are not taken to reduce the
projected increase in greenhouse gas emissions, the Earth’s
climate is projected to change at a rate unprecedented in the last
10,000 years with adverse consequences for society, undermining
the very foundation of sustainable development.
Policymakers are faced with responding to the risks posed by
anthropogenic emissions of greenhouse gases in the face of
significant scientific uncertainties. They may want to consider
these uncertainties in the context that climate-induced
environmental changes cannot be reversed quickly, if at all, due
to the long time scales (decades to millennia) associated with the
climate system. Decisions taken during the next few years may
limit the range of possible policy options in the future because
high near-term emissions would require deeper reductions in the
future to meet any given target concentration. Delaying action
would increase both the rate and the eventual magnitude of climate
change, and hence adaptation and damage costs.
Policymakers will have to decide to what degree they want to
take precautionary measures to limit anthropogenic climate change
by mitigating greenhouse gas emissions and enhancing the
resilience of vulnerable systems by means of adaptation.
Uncertainty does not mean that a nation or the world community
cannot position itself better to cope with the broad range of
possible climate changes or protect against potentially costly
future outcomes. Delaying such measures may leave a nation or the
world poorly prepared to deal with adverse changes and may
increase the possibility of irreversible or very costly
consequences. Options for mitigating change or adapting to change
that can be justified for other reasons today and make society
more flexible or resilient to anticipated adverse effects of
climate change appear particularly desirable.
- Climate
Science "In Play",
Robert T. Watson, Chair Of The Intergovernmental Panel
On Climate Change(IPCC), Keynote Speech At The Sixth
Conference Of The Parties To The United Nations
Framework Convention On Climate Change (UNFCCC),
November 13, 2000
An Electoral Butterfly Effect, Nature
Robert Sinclair of the University of Alberta and
colleagues report in a Brief Communication this week that some
Canadian shoppers made a crucial mistake in simulated voting, for
a Canadian prime minister, of exactly the type that may have given
Pat Buchanan votes intended for Al Gore. Of 53 people using the
double-column butterfly ballot, four made mistakes; three of these
involved voting for the candidate in the wrong column. By
contrast, a similarly sized group of shoppers given a simpler,
single-column ballot made no mistakes.
"Here we show that not only is the double-column butterfly
ballot more confusing than a single-column ballot, but that it
also appears to cause systematic errors in voting which call into
question the validity of the results from Palm Beach County in the
2000 United States presidential election. To test whether the
butterfly ballot format is likely to confuse voters, we asked
Canadian college students to vote for a prime minister of Canada
on the day after the presidential election in the United States
(…) "
- An
Electoral Butterfly
Effect, Robert C.
Sinclair, Melvin M. Mark, Sean E. Moore, Carrie A.
Lavis, Alexander S. Soldat, Nature Prepublication,
408, 665-666; 2000
-
Biannually a conference is held in Amsterdam to consider,
in a free and generous spirit, questions that prove fundamental to
research (in new as well established as areas). These prestigious
meetings are entitled: "Problems of ". The 12th meeting, in 2001,
will explore Problems of Individual Emergence.
Individual emergence refers to the reverse of collective
emergence, i.e. the phenomenon that the sum of the parts may be
more than the whole. The aim of the conference is to study what
permits parts to be or become more than any whole constituted of
these parts.
Individuals in composites or collectives often develop new or
improved values, abilities and properties they are not otherwise
able to develop. That such qualities sometimes complement, or even
conflict with, each other appears due to the possibility that
individuals are part of many collectives at the same time.
Qualities defined by composites or collectives apparently
include the ability to behave intelligently, take initiatives, be
compassionate, use and develop languages, show observer-effects in
experiments-as may be argued on the basis of their opposites, i.e.
people on occasion behaving as wolves to each other (homo homini
lupus).
- Problems
of Individual
Emergence, April
16-20, 2001 -Amsterdam, UK Cybernetics Society,
Systeemgroep Nederland, Lincoln Research Centre,
Center for Innovation and Cooperative Technology of
the University of Amsterdam
- Contributed by Marshall
Clemens
Links & Snippets
1 Changes In Deep-Water Formation During The Younger Dryas, Nature
Excerpt: Here we present such an analysis of the
large fluctuations in atmospheric 14C concentrations, of
unclear origin, that occurred during the Younger Dryas cold
period. We (…) model past production rates of
radionuclides, and find that the largest part of the
fluctuations in atmospheric radiocarbon concentrations can be
attributed to variations in production rate. The residual
difference between measured 14C concentrations and those
modeled using the 10Be record can be explained with an
additional change in the carbon cycle, most probably in the
amount of deep-water formation.
2 Triggering Of Earthquake Aftershocks By Dynamic Stresses, Nature
Excerpt: It is thought that small 'static' stress
changes due to permanent fault displacement can alter the
likelihood of, or trigger, earthquakes on nearby faults. Many
studies of triggering in the near-field, particularly of
aftershocks, rely on these static changes as the triggering
agent and consider them only in terms of equivalent changes in
the applied load on the fault. Here we report a comparison of
the aftershock pattern of the moment magnitude Mw = 7.3 Landers
earthquake, not only with static stress changes but also with
transient, oscillatory stress changes transmitted as seismic
waves (that is, 'dynamic' stresses). (...)
3 Visualization of Cooperation in the Construction of a Monolithic Building, Simulation
When a monolithic construction is being erected, a strict
regime must be followed on the thickness of a concrete layer
and on the layer's solidification time. This regime can only be
satisfied if all the cooperating ele-ments (a concrete mixer, a
crane, gangs working at the top of a building) har-monize.
Assuming constant parameters of the co-operating elements (but
no constant increase of the construction within a 24-hour
period is required), this paper presents the CoMB program,
which dynamically visualizes this harmonization and reports the
percentage of usage of co-operating elements. A didactic aspect
of such a visualisation is outlined.
4 This Campus Is Being Simulated, NYTimes
Excerpt: "While it has become a truism that the
Internet will revolutionize higher education, there is some
confusion as to exactly whose experience is likely to be
transformed. GEN expects to do about 90 percent of its business
with adult learners, who would be taking noncredit classes, and
the remaining 10 percent with high school students, who would,
or so the theory goes, receive Advanced Placement credit for a
GEN class. Only somewhere down the road would GEN be colonizing
the campus itself. At least in the immediate future, the elite
institutions will function principally as producers, rather
than consumers, in the online marketplace."
5 Stem Cells Hear Call of Injured Tissue, Science
In animal models, injected stem cells travel to tissue
injured by stroke, Alzheimer's-like plaques, contusions, or
spinal cord bruises, sometimes traversing long distances.
Several teams reported these surprising results this month at
the Society for Neuroscience annual meeting. No one knows
exactly how stem cells detect these different kinds of damage,
but researchers hope that the cells' migratory powers can be
harnessed to either replace dead tissue or deliver therapeutics
right where they're needed.
-
A NAME="15.6">
Gottfried,
Item for Complexity Digest:
I recently came across an excellent review of two of
Richard Lewontin's recent books. The books, "It Ain't
Necessarily So: The Dream of the Human Genome and Other
Illusions" and "The Triple Helix: Gene,
Organism and Environment" present a complexity view
of the present state of biological knowledge. The case for
complexity, and the fascination of its subtleties,is well
presented by the reviewer, Rob Dorit of Yale.
The review is published in September-October 2000 issue
of American Scientist, and is on-line at
http://www.amsci.org/amsci/bookshelf/Leads00/Dorit.html.
