Protein Folding And Unfolding On A Complex Energy Landscape, PNAS 
Protein folding is one of those miraculous,
life-sustaining processes that are going on in our cells all the
time and at an amazing speed. For years scientists have struggled
to find the pathways along which a protein would move from an
un-folded to a folded state and back.
More recently a theoretical approach familiar from the study of
complex adaptive systems has led to a new perspective about how
this process could take place: Instead of each protein having a
prescribed path from one state to the other, it is also feasible
to imagine that under identical external conditions depending on
microscopic details of their initial state, different proteins
might follow different pathways during the folding/unfolding
process. The shape of energy landscapes would guide the ensemble
of those pathways: Given external conditions for which the
unfolded state would be stable the folded protein could be
visualized as a point high on the slopes of a slippery landscape.
This state-space point would then rapidly slide "down" to a lower
energy state that corresponds to the unfolded configuration.
The experimental side of protein folding science also has mode
considerable progress so that it is possible today to trigger
(e.g. with laser pulses) fast protein folding of certain
molecules. The Cold Shock Proteins (CspA) are among the fastest
folding proteins currently known. Extremely short (nanosecond)
laser pulses can cause a fast heating of the protein soup by as
much as 20 degrees and thereby trigger the cold-shock folding
process.
Leeson et al. could measure the kinetics traces (i.e. the
fraction of proteins that had not finished the folding transition)
as a function of time: after one millisecond the transition was
basically complete. Furthermore from the shape of the transition
curve they concluded that for small temperature changes a single
exponential function could fit well the data i.e. only a single
time scale was involved in the process and basically all proteins
follow the same path to the folded state. For higher temperature
differences two exponentials (or a "stretched" exponential) became
necessary to well describe the data, indicating that the different
proteins in the soup followed different pathways to their folded
state.
These results support the description of the protein folding as
a process that takes places on an energy landscape, illustrating
again the power of concepts from complex dynamical systems.
Protein
Folding And Unfolding On A Complex Energy
Landscape, Daan Thorn
Leeson, Feng Gai, Hector M. Rodriguez, Lydia M. Gregoret,
R. Brian Dyer, Proc. Natl. Acad. Sci. USA,
10.1073/pnas.040580397
Controlling Cell Functions With Noise, PNAS
Cells are an example of mesoscopic systems at a scale at
which "miracles happen", phenomena that can be categorized and
described but not completely explained in terms of detailed
microscopic mechanisms. There has been, however, significant
progress over the past years in discovering some of the rules and
programs that "run" a cell. It is no surprise that the
instructions for the cell about what to do next comes from the
genes. Gene expression and gene transcription are at the base of a
genetic regulatory network that effectively controls the cellular
functions. One important function of cells is the production of
specific proteins and it would be of tremendous medical and
pharmaceutical interest to have external control over this
process. But writing a gene program that tells the cell what part
of the genetic information to use and how has not only the problem
of input/out put interface. Even if it would be feasible to find a
way to write and implement such cellular nano-codes a significant
problem at those mesoscopic scales is the omnipresence of random
fluctuations that could easily mess up the best-designed codes.
Hasty et al. followed a different strategy: starting from
non-linear, stochastic dynamical systems, they developed a control
strategy that is immune against small errors: They take advantage
of one characteristic property of non-linear systems (like
transistors) namely that they can be under the same conditions in
different states (e.g. "on" vs. "off", dependent on their
history). In the case of the bacteriophage lambda the switching
variable is the production of lambda repressor protein. It can be
either in a low ("off") or high ("on") concentration state. In
model simulations they could show that external noises sources
could be used to "switch" the cell from the "off" to the "on"
state and back. Since according to the researchers the noise
switches could be implemented in the form of external electrical
fields. If these theoretical results can be confirmed
experimentally, this method would indeed be an important step on
the way to a powerful gene therapy.
Biodiversity Hotspots For Conservation Priorities, Nature
Ecosystems are prime examples of complex adaptive systems
and therefore their behavior is also highly non-linear: For
instance they can compensate for environmental impacts to a
certain degree but there might be a critical threshold that will
"break the camel's back". It seems that today we are witnessing on
a global scale the largest mass extinction of species since the
one that wiped out the dinosaurs 65 million years ago. From the
seven million known eukaryote species (plants and animals, not
counting bacteria) about two thirds are in about 8 million square
kilometers of tropical humid forests that are currently destroyed
at a rate of 1 million square kilometers every 5 to 10 years.
Myers et al. describe a study that identified 25 hotspots
around the globe that host the highest diversity of endemic
species - species that are found there, and only there - and that
are also especially threatened. The area of all the hotspots
together comprises about 1.4% of the land surface. In order to
distribute the limited funds available for species conservation in
the most efficient way they study ways to turn some of these
ecological hot-spots into a 21st century version of Noah's arc.
The cost for safeguarding these 25 hotspots would run about US $
500 million per year, a total that is small compared with
"subsidies of various sorts that degrade environments and
economies alike, amounting to $1.5 trillion annually
world-wide".
Biodiversity
Hotspots For Conservation
Priorities, Norman Myers,
Russell A. Mittermeier, Cristina G. Mittermeier, Gustavo
A. B. Da Fonseca & Jennifer Kent, Nature 403, 853 -
858 (2000)
-
One of the paradigm shifts introduced by the complex
systems view is to recognize the problem solving capabilities of
distributed and interacting agents. The governing metaphor can be
that of interacting neurons where learning takes place through
changing the configuration of synaptic strength. Alternatively -as
in the article by Bonabeau and Theraulaz- it can be that of swarms
of ants where learning happens through evaporating/forgetting)
pheromone trails. When Deneubourg presented his ant simulations at
the first artificial life conference it looked more like a cute
academic investigation. It would have been hard to imagine that
one day these concepts would be used to schedule paint jobs for
trucks or to build robots for cooperative transport of heavy
objects (http://www.cs.ualberta.ca/~kube/).
Other ant-inspired applications include customer clustering of
banks (similar to how ants pile the bodies of dead ants) or
improved routing strategies of communication networks. Artificial
ants also could be trained (and mutated) to find good solution to
one of the classical "NP hard" problems of complexity, the
traveling "sales-ant" problem. Natural ant species that have been
studied would be lousy for finding the shortest path to pass
through a number of cities (visiting each city only once): They
would easily get stuck on a traditional route that had been
frequently traveled before. But a slight mutation to create a
species that produces a pheromone that evaporates a little faster
(similar to scientists who do not read scientific publications
from more than a year ago) will produce an artificial ant species
that will keep exploring new routes until they find one that is
close to the optimum. (see http://www.cs.ualberta.ca/~kube/).
One might speculate that a couple of hundreds of millions of
years ago there might have been already a natural ant species with
short pheromone memory but maybe they didn't survive for more than
a couple of million years. Who would remember? After all, the rule
seems to be that if you are too good at something you won't make
it in the long run.
- Swarm
Smarts, Eric Bonabeau, Guy
Theraulaz, Scientific American, March 2000
Stem Cell Magic, Science
Imagine you drive in your old car and one day you notice
that the alternator is not alternating anymore. You open the trunk
and take out a "universal spare part (USP)" place it under the
hood, go for some donuts and coffee and by the time you come back
the USP has transmogrified itself to a functioning alternator.
That is sort of how I visualize how stem cells ("cells with the
capacity of prolonged self renewal that can produce at least one
highly differentiated descendant") work in our body.
The 25 Feb 2000 issue of Science has a special report on the
amazing results from recent stem cell research. While we all
learned how a single, unspecific zygote divides and eventually
produces cells that become more and more differentiated until they
eventual turn into hair, brain, or blood, etc. cells it now seems
that our body has taken precautions for expected malfunctioning of
some parts as we grow old and put a set of universal spare cells
aside. These are adult stem cells that might not be as universally
transformable into different other cells as embryonic stem cells
but it now seems that they still have an amazing flexibility in
replacing damaged cells in an adult organism. For instance it
seems that there are a number of different adult stem cells that
con be transformed into neuronal cells. On the other hand there is
evidence that nerve (stem) cells can develop into blood cells
depending on both intrinsic and extrinsic regulating signals. Some
of these signals have been identified and there is hope that one
day we learn how to control those regulating signals and apply
them for tissue replacement therapy.
- Why
Stem Cells?, Derek van der
Kooy, Samuel Weiss, Science 2000 287: 1439-1441
- Mammalian
Neural Stem Cells, Fred H.
Gage, Science, Volume 287, Number 5457, pp. 1433 -
1438
- Out
of Eden: Stem Cells and Their
Niches, Fiona M. Watt,
Brigid L. M. Hogan , Science 2000 287:
1427-1430
Thermal Stimulation Of Taste, Nature
Most people outside of England don't like lukewarm beer
and only eccentrics would put ice-cubes in their chicken soup. The
coupling between temperature and taste can be sometimes very
strong (Prussian king Frederic the Great had a special tunnel
built between his kitchen building and his palace to help keep his
soup hot) in other cultures like the Chinese cuisine it seems to
be less pronounced.
Cruz and Green studied in considerable experimental detail the
physiological origins of this binding between temperature and
taste perception. They selectively changed the temperature of
patches of one square centimeter at different locations on the
tongues of volunteers who then would report any sensation of taste
that they might experience. The applied temperatures were all in
the range between ice cream and hot soup.
The researchers could indeed confirm that something like
"thermal taste" does occur in many of the tested volunteers (21
out of 24): Warming of the tip of the tongue caused a sensation of
sweetness whereas a cooling of the same region invokes a
perception of sourness or saltiness. The same changes of
temperature applied to the rear of the tongue caused a weak
sensation of sweetness for increase in temperature and bitter to
sour tastes after a temperature decrease.
While the findings are statistically significant a number of
theoretical explanations have been proposed, none of them seems to
convincingly describe all phenomena.
You can test if you are among the thermal gourmets by putting
an ice cube on the tip of your tongue and check if it acquires a
sweet taste.
The Sound Of Many Hands Clapping, Nature
Self-organization of complex systems can take place in
space and/or in time and lead to the emergence of order parameters
with coherent behavior of the interacting subsystems. Collective
behavior of humans such as singing in a group is one classical
example of social temporal organization in humans. One example of
self-organized spatio-temporal behavioral pattern is the "wave"
observed frequently in US football stadiums.
Neda et al. studied an even simpler group activity: the
applause of theater and opera audiences in Romania and Hungary. In
their description of the self-organized transition from fast,
incoherent clapping to slower, synchronized clapping the authors
do not mention the cultural information content in the different
clapping patterns which provides an explanation for the
psychological motivation for the transitions: Whereas fast,
incoherent clapping is a signal for appreciation of the
performance, coherent, rhythmical clapping in many places in
Europe is a collective message from the audience to the
performers, a request for an encore. The increasing frequency (see
fig. 1e of Neda et al.) of the clapping is a measure for the
urgency of the request and it culminates in a transition back to
noise as when the performer re-appears to deliver the encore.
One interesting result is that at the onset of synchronized
clapping the period approximately doubles (1:2 mode locking in
terms of non-linear oscillators) before it slowly decreases to
basically the frequency of incoherent individual clapping. How
much of this phenomenon is cultural convention is not clear. But
according to fig. 1f-g in the same paper, individuals (in
Rumania/Hungary) knew what to do when asked to produce the two
different types of clapping: approximately three claps per second
when ask to clap as if they were part of a regular applause and
about half that rate when asked to clap in the form of rhythmic
applause.
It would be interesting to repeat the same experiment with an
audience of a different cultural background under controlled
experimental conditions. For instance from the work of Kelso's
group we would expect that clapping frequency can act as natural
bifurcation parameter of coordinated behavior.
-
In 1930 Kurt Godel, the brilliant and eccentric logician
from Austria proved the non-existence of a mathematical system
that is both complete (i.e. all possible statements can be derived
from axioms) and consistent. That implies that if we want to have
a consistent mathematical theory we have to allow the existence of
statements that are true but not provable. For his prove Godel
used self-referential systems that lead to paradoxical situations
like the barber of Seville who was asked to shave all men who
don't shave themselves (he happened to be a man). In the 1980's
Gregory Chaitin made a connection between Godel's theorem and
random numbers, numbers that cannot be constructed with an
algorithm shorter than the number itself. He called true
statements that cannot be derived from any axioms "random truths"
that just are and have no explanation.
In elementary particle physics ordinary particles are
surrounded by a field of virtual particles that lead to a
self-interaction with a number of peculiar properties that need to
be kept under control with a mathematical trick known as
"renormalization". According to Chown a theory proposed by Cahill
and Klinger has at their basis pseudo-objects that have no
intrinsic existence and are only defined through their interaction
with other pseudo-objects, similar to the monads of Leibniz.
Thanks to powerful computers one is not confined today to
philosophizing about the foundations of existence but one can do
computer simulations. Repeated random interactions among
pseudo-objects eventually leads to structure formation in the
interaction matrix in the form of "gebits" which display a scaling
law that is claimed to be characteristic for three-dimensional
space.
This model of our universe expands at an accelerating rate and
is speculated to be consistent with the recent findings about the
accelerating rate of expansion of our universe. The researchers
explain why pseudo-objects cannot be observed with the assumption
that they self-organize to a state of self-organized criticality
like Per Bak's sand pile.
Since conventional cosmology and elementary particle physics is
currently in a state of crisis one must not be surprised if very
unconventional approaches emerge. After all, science itself is a
complex, adaptive system.
-
Editor's Note: The following are titles and
abstracts of the conference Winter Chaos 2000, February 25 - 27,
2000, Wilburton Inn, Manchester Village, VT, Co-Organizers, Carlos
A. Torre, Mark Filippi.
ComDig publisher Dean LeBaron attended the conference and
recorded part of the sessions on digital video. We include links
to the video clips as an experiment in using video to report about
oral presentations. We would be interested in feedback on how well
these video clips help to share the presented information and
especially any suggestions for improvements.
The Novelty of Emergent Phenomena in Complex Systems, Jeffrey Goldstein, (Video)
One of the most striking features of emergent phenomena
is the radical novelty of their properties in relation to the
properties of the pre-existing components out of which they
emerge. How can this novelty be accounted for? What is required is
an understanding of a process powerful enough to be bring forth
radical novelty. To begin to appreciate such a process we need to
inquire into the constituent factors that could provide such
necessary potency. First, I will provide some examples of
emergence that demonstrate their radical novelty. Second, I will
discuss the factors of processes in general that can generate such
novelty. Finally, I will offer a simple mathematical procedure
that can reveal how radical novelty can be generated.
The Novelty
of Emergent Phenomena in Complex Systems, Jeffrey
Goldstein, Ph.D., Adelphi University
Features of Self-Organization in the Dreaming State, Wilfred Pigeon, (Video)
The rapid eye movement (REM) stage of sleep is a distinct
psychophysiological state during which most dreaming occurs.
Dreaming has been postulated by others to be the brain's
self-organization of the random neuronal activity that occurs in
REM. Post-traumatic stress disorder (PTSD) is a
psychophysiological response to one or more overwhelming stimuli
that is marked by disturbed sleep in general and REM disturbance
with nightmares in particular. PTSD has been postulated by others
to represent a loss in organizational complexity due to
dysregulated ultradian rhythms. This paper examines the centrality
of the self-organizational features of REM sleep in the context of
a developing PTSD syndrome. Both the physiological features of REM
and the psychological features inherent in the dream content are
hypothesized to correlate to the course of PTSD symptomatology.
Most PTSD studies have been conducted on patients with chronic,
long term PTSD. Research currently under way is examining patients
in a critical time period following traumatic injury. Preliminary
data from overnight polysomnography recordings and from dream
diaries of recently traumatically injured patients will be
presented.
Features of
Self-Organization in the Dreaming State: Implications for
Post-Traumatic Stress Disorder, Wilfred Pigeon,
Dartmouth Sleep Disorders Center, Lebanon, NH, The Union
Institute, doctoral candidate
-
In the mid nineteen-fifties, Gregory Bateson and his
coworkers articulated a theory of schizophrenia called double bind
theory, which argues that symptoms of schizophrenia are related to
the internalization of conflicting patterns of interaction within
the family. While originally seen as a theory with great
potential, the scholarly community gradually lost interest,
because researchers were not able to find empirical confirmation
for double bind, and those who originally developed the theory
gave insufficient direction to the confirmation process. Moreover
schizophrenia research revealed findings which were deemed
incompatible with double bind, because they indicated that the
disorder might to a great extent be constitutional rather than
acquired. Most recent models of schizophrenia acknowledge a
significant contribution of the environment as well as
constitutional processes, but this acknowledgment as not resulted
in a renewed interest in double bind.
It is argued in this presentation that to make double bind
theory compatible with modern insights in science in general,
schizophrenia research in particular, the following three things
need to happen. (1) Current insights in nonlinear dynamical
systems theory, which were implicit in Bateson's original theory,
need to be fully incorporated into Double Bind theory. (2) Double
bind ought to place family dynamics in a diathesis - stress
framework, the prevailing paradigm in contemporary schizophrenia
research. (3) Double bind theory needs to be made more accessible
to empirical research, so that the theory can be falsified. The
proposed presentation intends to make a beginning which the
development of each of these three points.
Three
Minimal Requirements For A Double Bind Theory Compatible
With Contemporary Knowledge About Schizophrenia,
Matthijs Koopmans
-
The Hearts & Minds Educational Research Project
explores the emotions children experience as they learn. It
examines how different educational processes and activities
mediate the experience of emotion and how these emotions encourage
or restrain children's ability to learn. Through the use of
recurrence plot analysis or RPA (a cutting-edge pattern analysis
and quantification technique ideally suited for analyzing the
shifts, drifts, and other idiosyncrasies of psychological and
physiological data sets), my work proposes to build on previous
and present research seeking to identify characteristic patterns
in the autonomic nervous system that are associated with specific
emotions: blood pressure; facial expressions; skin conductance
(Ekman, Izard, Davidson, and others). The objectives are to: 1)
Evaluate evidence of correlation between particular emotions and
patterns of variability in the time between heart beats (R-R
intervals); 2) Examine how these patterns vary among diverse
student populations (e.g., culture, gender, physical ability,
linguistic proficiency); and 3) assess how these patterns vary
across educational methodologies, teaching types/practices, and
curricula content.
Electrocardiogram (ECG) data were collected through Holter
monitors in an experiments with ten (N= 10) Kindergartners (five
monolingual -English- students [3 boys/2 girls] and five
bilingual education counterparts [2 boys/3 girls] -
understand English but are Spanish-dominant) engaged in several
classroom activities. Other relevant variables were kept constant
(i.e., socio-economic status). Design of the various activities
were guided by the mental processes proposed by the Principal
Investigators own Triadic Theory Of Mental Functioning: Cognitive
(recognition of numbers and colors); Affective/Perceptive (having
a story read to them, discussing how they felt); and
Pragmatic/"hands-on" (illustrating their favorite part of the
story through coloring, cutting, and pasting). Difficult
instructions and dialog were translated into Spanish, but most
activities were conducted in English.
The research hypotheses was supported: that, in the cognitive
and affective activities, cultural and linguistic differences
between the groups would result in different physiological
responses that go with emotions and, thus, in significant
differences in the variability of group patterns of R-R Intervals
(i.e., heartbeat intervals) and their attendant physiological
statistics. No significant differences were expected between the
groups in the pragmatic (or hands-on) activity. As expected, the
monolinguals had higher percentages of recurrences (less heartbeat
interval variability -- that is, more regularity) in both the
cognitive and the affective activities (7% points in both cases)
and almost no differences (less than .6%) in the pragmatic
activity.
Hearts
& Minds: A Dynamical Approach To Emotions And
Patterns Of Physiological Responsiveness, Carlos
Antonio Torre, Southern Connecticut State University,
Yale University
-
By examining personal connections to the "non-local"
social self, it may be better understood as to why humans
subluxate and how social patterns of adaptation through octal
coding can be better recognized and regulated. This process
reframes subluxation as a meme, a unit of cultural imitation, that
possesses an unbounded capacity to be non-verbally communicated
intra- and/or interpersonally.
With both doctor and patient focusing on common targets for
clinical outcomes, the emphasis shifts from normalizing the spine
to optimizing nerve function for whole body benefits on both a
personal and communal level. We conclude with the theoretical
rationale for a virtual adjustment, based on the evidence
presented.
Subluxation
As A Social/Cultural Imitation: Resolving A
Phylobiological Epiphenomenon, Mark R. Filippi, D.C.
In private practice: Larchmont, NY
Mapping the Dynamics of Change in Educational Systems, David Gibson, (Video)
I'll present the results of a ten year retrospective
study of five Vermont high schools, which occurred in two phases.
First, a qualitative research team developed quantified data and
timelines of events and reached some preliminary conclusions.
Second, systems dynamics simulation models were developed that
used the data as settings on key parameters and allowed the models
to emulate the real school system settings. A recent proposal to
the NSF builds on this experience in order to create a
multidisciplinary research team to study large scale reform in two
state level sites.
Mapping the
Dynamics of Change in Educational Systems, David
Gibson, Senior Associate with the Natl. Inst. for
Community, Innovations and Professional Development
Specialist with the Vermont Institute for Science,
Mathematics and Technology.
Nature and Dynamics of Organisms in Environment, Val K. Bykoski, (Video)
The nature and dynamics of organisms in environment is
discussed in terms of organism's physical substrate. The concept
of substrate is an attempt to integrate physical, biological, and
social domains via a generic physical substrate described at the
level of its electronic structure and functions rather than in
abstract parametric terms. The substrate is modeled as an
aperiodic crystal with adaptive capabilities. A elementary cell of
the substrate is identified and its electronic properties
described quantum mechanically. The cell has generic composition
MGLNPP` (metalglycolipoproteinphosphate), and the substrate is
indeed a 3D polymer (MGLNPP`)n. So, the elementary cells and the
substrate have a variable composition. DNA, RNA, and other
important biological macromolecules are particular cases of this
generic formulae (MGLNPP`)n, It can be shown that the H atoms in
hydrogen bonds inside a cell are in metastable quantum (tunnel)
state. They may change their locations and, therefore, update the
current base pair encoding, according to Watson-Crick model. The
example of GC and AT base pairs bonded via H atoms is discussed in
details. The lattice of H atoms forms a sort of control memory,
and its spatial encoding determines the spatial structure and
function of the substrate. Within substrate, a composition and
function of a cell depends on its location as well as on
environmental impacts. An emergent hierarchical structure of an
organism can be deduced as a result of continuous changes of its
substrate under control of environment.
Few alarming trends in organism dynamics in a highly demanding
environments are identified and briefly discussed in terms of the
substrate/organism integration and disintegration trends. These
trends are due to the mismatch between organism dynamics and
environment dynamics. If environment requires quick response which
is much faster than the organism is able to offer, the organism's
physical choice is to split into autonomous sub-units, "smaller
and faster" and better adapted to the high-speed environment. The
same trend probably was the reason for splitting of originally
sexless hypothetical "-organism into two spatially complementary
units (guess who?). Indeed, the 2-unit team is able to explore
environment (say, for food) twice faster than a single organism
who has to explore environment sequentially, area by area. In
addition, the smaller organism is always faster in terms of
response time. At this point in evolution history, due to the
developed communication and delivery infrastructure, the
separation into sexes ("as we know it"), being in the past the
fundamental exploration enhancement tool, unfortunately loses its
ground. Numerous examples of flexible organism dynamics in
novelty-rich environments are identified and briefly
discussed.
Various models of novelty-rich environments designed to
demonstrate environment-driven drastic changes in cellular and
organism dynamics are discussed. In particular, a high-performance
novelty generator based on computer-driven silicon chip directly
interfaced with a real substrate (such as cellular culture or
tissue) is discussed. The estimates are made which indicate that
the performance of such a generator would be enough to demonstrate
the environment-driven changes in structure and functions of the
substrate.
Nature and
Dynamics of Organisms in Environment, Val K. Bykoski,
University of Massachusetts at Lowell and Xerox Corp.,
Burlington, MA
Re-Forming Schools: Perceptions and Patterns of Change, Debra Kosemetzky, (Video)
For more than one hundred years, education has been
pointed to as the root of society's problems and hoped for as the
panacea for social change and prosperity. This review of
educational reform literature builds on the historical research of
Cuban (1990) and Cuban and Tyack (1995) who suggest that education
reform is repeated again and again as educational systems try to
reinvent themselves. There have been several predominant models of
educational change and recurring reform cycles. While there are
different perspectives about the role of education, the
educational reform models are fundamentally rooted in the
rationalist paradigm. This review will help to ground the larger
research study that explores why repeated reform efforts are
difficult and will have little impact on "improving" education
until the dynamics of change in education is understood from a
complex systems perspective.
Re-Forming
Schools: Perceptions and Patterns of Change, Debra
Kosemetzky, OISE/University of Toronto, Ed.D.
candidate
Complexity in the Fusion Between Taste and Smell to Obtain Flavor, Virginia Utermohlen, (Video)
When we perceive the flavor of a food, we actually
perceive the result of the brain's analysis of signals from the
taste system in the mouth, coupled with signals from the olfactory
system in the nose. We do not separate taste from smell as we eat
-- we only perceive flavor through a process of sensor fusion.
Sensor fusion is a prerequisite for the full appreciation of
flavor -- signals from taste alone or smell alone are inadequate.
In sensor fusion, the senses that are fused can provide
complementary observations, competing observations, and/or the
process of sensor fusion can provide for coordination between
observations. In the case of flavor, it has been assumed that
taste and smell provide complementary information -- that is,
evidence from the taste system completes and enhances in some way
evidence from the olfactory system, and/or vice versa. The data we
have obtained would suggest that sensor fusion in the taste-smell
system is a complex process, which cannot be explained through a
linear summation of taste and smell inputs. We will present data
supporting this contention, as well as a neural network model that
may explain these data.
Complexity
in the Fusion Between Taste and Smell to Obtain
Flavor, Virginia Utermohlen, Division of Nutritional
Sciences, Cornell University, Ithaca, NY 14853 USA
-
Even our most well understood and best loved "truths"
crumble under just a few innocently asked questions. And, we are
then left with one final question to ponder -- "What is the
Universe like?"
This really large question is usually just avoided by most
theorists in psychology (save in some small way George Kelly and
Gestaltists) but must be addressed if a truly coherent theory is
to be expressed. My hope for this talk is to spend some time
explaining my view of the universe and how the theory I espouse
falls quite logically from it.
The
Universe Is Ö, Rick Paar, Ph.D., Department of
Psychology, Springfield College
