Complexity Digest 2001.47

19-Nov-2001

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Content

  1. The Computational Perspective, Edge
  2. Liquid Computing, Harvard Magazine
  3. Musicians' Brains Wired For Sound, CNN/AP
    1. You're Right, Shakespeare: Music And Sweet Poetry Agree, Soc Neuroscience
  4. Choice Behavior of Drosophila Facing Contradictory Visual Cues, Science
  5. Out on a Limb, or a New Branch of Signalling Theory?, HMS Beagle
  6. Semiconductors Get On Our Nerves, Nature
  7. To Be Remembered, Forget Praise. Give Money, Society for Neuroscience
  8. Grandmother Calls In The Reserves, Society for Neuroscience
  9. Single Gene Dictates Ant Society, Science
  10. New Pufferfish Genome May Offer Clues To Humans, Reuters
  11. Novel Motor Gestures Enhance The Acoustic Complexity Of Birdsong, Proc R Soc Lond
  12. Circadian Systems: Different Levels Of Complexity, Philos Trans R Soc Lond
    1. The Neurospora Circadian Clock: Simple Or Complex?, Philos Trans R Soc Lond
    2. Genetic Interactions Between Clock Mutations In Neurospora Crassa: Can They Help Us To Understand Complexity?, Philos Trans R Soc Lond
  13. The Significance Of Sentence Disruptions In The Development Of Grammar, J Speech Lang Hear Res
  14. A Variable Sun Paces Millennial Climate, Science
    1. Cornell's Digital Earth Project, Cornell Press Release
  15. Formation Of Coastline Features, Nature
  16. Weather Forecasters Look Ahead, Far Ahead, NYTimes
  17. On Complexity and Emergence, Complexity International
  18. Introduction to High-Frequency Finance, Academic Press
  19. Complex Challenges: Global Terrorist Networks
    1. Surprise. War Works After All, NYTimes
    2. Soldiers Play 'Virtual Reality' Training Games, Reuters
  20. Links & Snippets
    1. Other Papers
    2. Conference Announcements

  1. The Computational Perspective, Edge Next Article Bookmark and Share

    Editor's Note: There is an ongoing debate about viewing the brain as some form of a computer or, more recently, as a complex adaptive system. Of course both concepts of computation and complexity are not strictly defined and so the author can present a computational perspective that is wide enough to include essential characteristics of complex systems. The progress in this view is that the original, more narrow interpretation of computation has been abandoned. This certainly will help to focus future discussions in more constructive directions than debating over the computational equivalent of the question if a virus is a living being.

    Excerpt: And when you look at them you see that at a very fundamental level they're basically computational. That is to say, there are algorithms for growth, development, and reproduction. The central binding idea of all of these phenomena is that you can put together not billions, but trillions of moving parts and get these entirely novel, emergent, higher-level effects. And the best explanation for what governs those effects is at the level of software, the level of algorithms. If you want to understand how orderly development, growth, and cognition take place, you need to have a high-level understanding of how these billions or trillions of pieces interact with each other.


  2. Liquid Computing, Harvard Magazine Next Article Bookmark and Share

    Excerpt: Lieber has "philosophical differences" with the industry's "top-down" approach to nanotechnology--taking big things and making them smaller. "The way to truly revolutionize the future," he says, "is to take a completely different approach: build things from the bottom up." He has done that by starting with the smallest of building blocks--wires only three nanometers across that can be produced relatively cheaply on a bench top with a few thousand dollars' worth of equipment.

  3. Musicians' Brains Wired For Sound, CNN/AP Next Article Bookmark and Share

    Excerpts: Neuroscientists, using brain-scanning MRI machines to peer inside the minds of professional German violinists, found they could hear the music simply by thinking about it, a skill amateurs in the study were unable to match. (…)

    "When the professionals move their fingers, they are also hearing the music in their heads," Scheler said.

    Amateurs, by contrast, showed more activity in the motor cortex, the region that controls finger movements, suggesting they were more preoccupied with hitting the correct notes, she said.


    1. You're Right, Shakespeare: Music And Sweet Poetry Agree, Soc Neuroscience Next Article Bookmark and Share

      Contributing Editor's Note: What are connections between speech and music or between listening and performing? To experimentally find this, the above researchers inserted a special device consisting of a ring of speakers into a positron emission tomography (PET) scanner. Volunteers listened to sounds from different angles and used a joystick to point to the source of a sound. The findings are reported below.

      Excerpts: When different sounds are played from different angles, a specialized region within the auditory cortex becomes activated. A second area, in the mysterious parietal cortex, became active when the volunteers tried to identify the location of the sounds. The amount of activity in the area, located in the right parietal lobe, closely predicted how accurately the volunteers could locate a sound. "There has been much debate among scientists about what the parietal cortex does, (...) our study demonstrates that this region probably integrates the information from the auditory cortex with information from the visual and motor systems."


  4. Choice Behavior of Drosophila Facing Contradictory Visual Cues, Science Next Article Bookmark and Share

    Excerpts: We studied the underlying neural mechanism of a simple choice behavior between competing alternatives in Drosophila. In a flight simulator, individual flies were conditioned to choose one of two flight paths in response to color and shape cues; after the training, they were tested with contradictory cues. Wild-type flies made a discrete choice that switched from one alternative to the other as the relative salience of color and shape cues gradually changed (…). Thus, Drosophila genetics may be useful for elucidating the neural basis of choice behavior.

  5. Out on a Limb, or a New Branch of Signalling Theory?, HMS Beagle Next Article Bookmark and Share

    Excerpts: Could it be that one of nature's most dazzling displays is just a "keep out" sign to insects? According to Hamilton and Brown's recent analysis [1] of published data, the autumnal change in leaf color of temperate deciduous trees is a handicap signal to their insect pests, revealing the commitment of the trees to defense. (…) The scope for handicap signals in plants is perhaps more limited, at least to our current view, but the area of plant-herbivore interactions is one in which they could evolve.

  6. Semiconductors Get On Our Nerves, Nature Next Article Bookmark and Share

    Excerpt: But it is hard to get a smooth dialogue going between neurons and semiconductors. Nerve cells tend to grow over every surface in sight, like lichen over stone, but they don't stick very closely. The gap they leave produces a poor electrical contact.

    Schmidt's team creates specific, intimate links between neurons and semiconductors using a small protein fragment. One end of this peptide latches onto a nerve cell's surface; the other sticks to the surface of the semiconductor. Being small, the peptide holds the two surfaces closely together.


  7. To Be Remembered, Forget Praise. Give Money, Society for Neuroscience Next Article Bookmark and Share

    Contributing Editor's Note: What is the process of recalling from the memory. One aspect of the answer is from neurophysiology of the brain, other aspect is from psychological point of view. There exists a 'weight' attached to the memory of any particular experience which weight makes it fit (or unfit) for retrieval. The investigators based on the experiment below, finds the 'weight' to be financial reward (here, a dollar)- not social reinforcement (here, praise).

    Excerpts: Psychologists have known for years that we tend to remember emotionally loaded experiences better than neutral ones, but they don't yet know how we do it.

    (...) had three groups of subjects try to memorize a list of 30 words. After testing them for recall immediately afterward, (...) researchers praised one group, did nothing for another group, and paid a third group a dollar. When the subjects returned a week later (...), all three groups performed about the same on a recall test. But a week later, those that were paid performed significantly better than those that were praised.


  8. Grandmother Calls In The Reserves, Society for Neuroscience Next Article Bookmark and Share

    Contributing Editor's Note: Aging is associated with loss of memory. Whatever be the name of this phenomena, the basic issue is which part of the brain is responsible for this. The prefrontal area of the brain takes the biggest hit in normal aging and loss of prefrontal cortex also correlates with faltering cognitive performance in the older subjects. according to the above investigators.

    Excerpts: More evidence for loss of brain with age came from PET studies of the dopamine system (...). Not just receptors are lost; many different aspects of dopamine function decline with age. This is not a loss of cells, as in Parkinson's disease, but an across-the-board slowing of dopamine transmission, with less transmitter released and faster metabolism of that which is made.
    > (...) people who age successfully compensate for these losses by engaging both hemispheres when the young use just one. The young also show action in both halves of the brain, he says, during complex mental tasks.


  9. Single Gene Dictates Ant Society, Science Next Article Bookmark and Share

    Excerpt: Genes regulating behavior are very hard to pinpoint; even basic behaviors are thought to be influenced by many genes interacting in mysterious ways. But fire ant researchers at the University of Georgia say they've characterized a gene that may single- handedly determine a complex social behavior: whether a colony will have one or many queens. The gene in question seems to work by controlling how ants perceive pheromones that tell them who's a queen and who isn't.

  10. New Pufferfish Genome May Offer Clues To Humans, Reuters Next Article Bookmark and Share

    Excerpt: (...) Singaporean scientists released the genetic blueprint of the Japanese pufferfish on Friday, saying it will help speed up understanding of the human genome.

    The Japanese pufferfish, or Fugu rubripes, is the first vertebrate genome sequence to be completed after the map of the human genetic code was unveiled earlier this year. (...)

    The fugu, a popular Japanese delicacy which puffs up into a spiky baseball-sized globe when threatened, is expected to provide vital clues to how human genes are regulated. The fugu is separated from humans by a 450-million-year evolutionary gap. Similar regulatory sequences found between the two are believed to be essential for survival. (...)


  11. Novel Motor Gestures Enhance The Acoustic Complexity Of Birdsong, Proc R Soc Lond Next Article Bookmark and Share

    Abstract: Sound generation based on a pulmonary mechanism typically occurs during the expiratory phase of respiration. Phonation during inspiration has been postulated for the calls of some amphibians and for exceptional sounds in some human languages. No direct evidence exists for phonation during inspiration in birds, but such a mechanism has been proposed to explain very long uninterrupted songs. Here, we report the first physiological evidence for inspiratory sound production in the song of the zebra finch (Taeniopygia guttata). Motor gestures of the vocal and respiratory muscles leading to the production of inspiratory phonation differ from those of silent inspirations during song as well as from those leading to phonation during expiration. Inspiratory syllables have a high fundamental frequency, which makes them acoustically distinct from all other zebra finch song syllables. Furthermore, young zebra finches copy these inspiratory syllables from their tutor song, producing them during inspiration. This suggests that physical limitations confine the production of these sounds to the inspiratory phase in zebra finches. These findings directly demonstrate how novel respiratory-vocal coordination can enhance the acoustic structure of birdsong, and thus provide insight into the evolution of song complexity.

  12. Circadian Systems: Different Levels Of Complexity, Philos Trans R Soc Lond Next Article Bookmark and Share

    Abstract: After approximately 50 years of circadian research, especially in selected circadian model systems (Drosophila, Neurospora, Gonyaulax and, more recently, cyanobacteria and mammals), we appreciate the enormous complexity of the circadian programme in organisms and cells, as well as in physiological and molecular circuits. Many of our insights into this complexity stem from experimental reductionism that goes as far as testing the interaction of molecular clock components in heterologous systems or in vitro. The results of this enormous endeavour show circadian systems that involve several oscillators, multiple input pathways and feedback loops that contribute to specific circadian qualities but not necessarily to the generation of circadian rhythmicity. For a full appreciation of the circadian programme, the results from different levels of the system eventually have to be put into the context of the organism as a whole and its specific temporal environment. This review summarizes some of the complexities found at the level of organisms, cells and molecules, and highlights similar strategies that apparently solve similar problems at the different levels of the circadian system.

    1. The Neurospora Circadian Clock: Simple Or Complex?, Philos Trans R Soc Lond Next Article Bookmark and Share

      Abstract: The fungus Neurospora crassa is being used by a number of research groups as a model organism to investigate circadian (daily) rhythmicity. In this review we concentrate on recent work relating to the complexity of the circadian system in this organism. We discuss: the advantages of Neurospora as a model system for clock studies; the frequency (frq), white collar-1 and white collar-2 genes and their roles in rhythmicity; the phenomenon of rhythmicity in null frq mutants and its implications for clock mechanisms; the study of output pathways using clock-controlled genes; other rhythms in fungi; mathematical modelling of the Neurospora circadian system; and the application of new technologies to the study of Neurospora rhythmicity. We conclude that there may be many gene products involved in the clock mechanism, there may be multiple interacting oscillators comprising the clock mechanism, there may be feedback from output pathways onto the oscillator(s) and from the oscillator(s) onto input pathways, and there may be several independent clocks coexisting in one organism. Thus even a relatively simple lower eukaryote can be used to address questions about a complex, networked circadian system.
      The Neurospora circadian clock: simple or complex?, Bell-Pedersen D, Crosthwaite SK, Lakin-Thomas PL, Merrow M, kland M., Philos Trans R Soc Lond B Biol Sci. 356(1415):1697-709.

    2. Genetic Interactions Between Clock Mutations In Neurospora Crassa: Can They Help Us To Understand Complexity?, Philos Trans R Soc Lond Next Article Bookmark and Share

      Abstract: Recent work on circadian clocks in Neurospora has primarily focused on the frequency (frq) and white-collar (wc) loci. However, a number of other genes are known that affect either the period or temperature compensation of the rhythm. These include the period (no relationship to the period gene of Drosophila) genes and a number of genes that affect cellular metabolism. How these other loci fit into the circadian system is not known, and metabolic effects on the clock are typically not considered in single-oscillator models. Recent evidence has pointed to multiple oscillators in Neurospora, at least one of which is predicted to incorporate metabolic processes. Here, the Neurospora clock-affecting mutations will be reviewed and their genetic interactions discussed in the context of a more complex clock model involving two coupled oscillators: a FRQ/WC-based oscillator and a 'frq-less' oscillator that may involve metabolic components.


  13. The Significance Of Sentence Disruptions In The Development Of Grammar, J Speech Lang Hear Res Next Article Bookmark and Share

    Abstract: This research explored the relationship between sentence disruptions and the length and complexity of sentences spoken by children developing grammar. (...) The active, declarative sentences produced by these children were coded for the presence of disruption, length in morphemes and words, and clausal complexity. The results showed that, for the majority of the children, disrupted sentences tended to be longer and more complex than fluent sentences. The magnitude of the differences in length and complexity was positively correlated with the children's grammatical development, as measured by the Index of Productive Syntax. It was also found that differences between the average complexity of disrupted versus fluent sentences increased with grammatical development even when sentence length was held constant. As grammatical development proceeded, disrupted sentences were more apt to be sentences on the "leading-edge" of the child's production capacity. Although these more advanced grammatical structures are part of the child's grammatical competence, the child cannot produce these sentences without an increased risk of processing difficulty. The results are congruent with proposals concerning the incremental and procedural nature of adult sentence production.


  14. A Variable Sun Paces Millennial Climate, Science Next Article Bookmark and Share

    Summary: Most scientists have viewed the sun's unvarying brightness as the one constant in the ever-changing climate system. Now, in a paper published online this week by Science, paleoceanographers report that the climate of the northern North Atlantic has warmed and cooled nine times in the past 12000 years in step with the waxing and waning of the sun. Some researchers say the data make solar variability the leading hypothesis to explain the roughly 1500-year oscillation of climate seen since the last ice age, and that the sun could also add to the greenhouse warming of the next few centuries.

    1. Cornell's Digital Earth Project, Cornell Press Release Next Article Bookmark and Share

      Excerpt: (...) An institute at Cornell University is building a "digital Earth" that will become an important resource for geoscience researchers and also will provide easy-to-use teaching tools for educators from elementary school through college.

      The Digital Earth Project, part of the Cornell Geoscience Information System (GIS), is a global database created by the Institute for the Study of the Continents (INSTOC) at Cornell to make accessible geological information accumulated by Cornell researchers over the last eight years. The GIS includes over 100 different data sets on the structure of the Earth's crust, location of earthquake faults, a record of earthquake and volcanic events, magnetic and gravity measurements and descriptions of aquifers, along with details of surface topography. (...)


  15. Formation Of Coastline Features, Nature Next Article Bookmark and Share

    Excerpt: Alongshore sediment transport that is driven by waves is generally assumed to smooth a coastline. This assumption is valid for small angles between the wave crest lines and the shore, as has been demonstrated in shoreline models. But when the angle between the waves and the shoreline is sufficiently large, small perturbations to a straight shoreline will grow. Here we use a numerical model to investigate the implications of this instability mechanism for large-scale morphology over long timescales.


  16. Weather Forecasters Look Ahead, Far Ahead, NYTimes Next Article Bookmark and Share

    Editor's Note: Chaos theory predicts that weather forcasting becomes exponentially difficult as the forcasting time is extended. There is a strong economic incentive to push that limit far, if not too far.

    Excerpts: Competing for companies and consumers seeking reliable weather information, commercial forecasters are sharply expanding the boundaries of their predictions.

    Not long ago, five, six or seven days was considered the practical limit for accurately forecasting temperature and precipitation in a particular place at a particular time. (…)

    Last fall, Weather.com pushed its ZIP-code-by-ZIP- code predictions out from 7 days to 10. (…) These forecasts are the foundation on which the commercial products are built.

    Last spring, Accuweather.com countered by offering detailed forecasts up to 15 days ahead.


  17. On Complexity and Emergence, Complexity International Next Article Bookmark and Share

    Abstract: Numerous definitions for complexity have been proposed over the last half century, with little consensus achieved on how to use the term. A definition of complexity is supplied here that is closely related to the Kolmogorov Complexity and Shannon Entropy measures widely used as complexity measures, yet addresses a number of
    > concerns raised against these measures. However, the price of doing this is to introduce context dependence into the definition of complexity. It is argued that such context dependence is an inherent property of complexity, and related concepts such as entropy and emergence. Scientists are uncomfortable with such context dependence, which smacks of subjectivity, and this is perhaps the reason why little agreement has been found on the meaning of these terms.

    Contributing Editor's Note: Since complexity (and simplicity) is given at different levels, indeed it seems that there is no way of defining an absolute measure of complexity. For example how could we compare the complexity of a cell with the complexity of a galaxy? We can only define complexety relatively, in dependence of a context.


  18. Introduction to High-Frequency Finance, Academic Press Next Article Bookmark and Share

    Excerpt: Newly published by Harcourt's Academic Press, the Olsen Group's Introduction to High-Frequency Finance is the first and only source of unified information about this exciting young field.

    As Benoit Mandelbrot, Sterling Professor of Mathematical Sciences at Yale, comments: "At long last, the study of financial prices is moving beyond convenient oversimplifications. For providing much of the best data and an indispensable bridge between the financial and academic communities, this flowering is deeply indebted to the group led by D. Richard Olsen. (Their) work, which I often quote, has now been collected and extended in a book. I shall wear it out by constant use and it is a delight to recommend it to the emerging rational finance community."


  19. Complex Challenges: Global Terrorist Networks Next Article Bookmark and Share

    Excerpt: In many ways, the combination of tactics probably could not have succeeded even a decade ago, when Americans were still used to assuming that stalemate was likely, even inevitable. For military planners, the nightmare was "quagmire"; military doctrine called for avoiding any war where Americans couldn't overwhelm the enemy and also assure themselves a way out.

    (…) Cells of terrorists are seen as a bigger threat than Russian divisions.


    1. Surprise. War Works After All, NYTimes Next Article Bookmark and Share

      Editor's Note: Maybe it is a little early to draw any conclusions about how well "war works" in this case.


    2. Soldiers Play 'Virtual Reality' Training Games, Reuters Next Article Bookmark and Share

      Excerpt: In the new games unveiled by the Institute, players become enveloped in lifelike wartime environments helped along with extremely accurate lighting and surround sound. They converse and interact with lifelike virtual people on huge movie screens who know military strategy, show emotions, and respond to complex thoughts and speech patterns in sometimes unexpected ways.

      (…) one simply clicks a mouse to "modify" the meek lieutenant's "defensiveness level," thereby creating a different set of potential circumstances.


  20. Links & Snippets Next Article Bookmark and Share

    1. Other Papers Next Article Bookmark and Share

      1. Water, Water Somewhere -- We Think -- On Mars, Robert C. Cowen, The Christian Science Monitor, 11/1/01
      2. Sufferers From Glaucoma, Cataracts And Other Low-Vision Disorders Could Be Aided By Cornell Computer Graphics Technology, Cornell Press Release, 11/7/01
      3. Why Are Arthropods Segmented?, Budd GE., Evol Dev. 2001 Sep-Oct;3(5):332-42
      4. The Leading-Edge: The Significance Of Sentence Disruptions In The Development Of Grammar, Rispoli M, Hadley P., J Speech Lang Hear Res. 2001 Oct;44(5):1131-43
      5. Sugared Soda Consumption And Dental Caries In The United States, Heller KE, Burt BA, and Eklund SA J Dent Res 2001 Oct 80(10): p. 1949-53
      6. Molecular Complexity And Dynamics Of Cell-Matrix Adhesions, Zamir E and Geiger B, J Cell Sci 2001 Oct 114(Pt 20): p. 3583-90
      7. EEG Source Localization And Global Dimensional Complexity In High- And Low- Hypnotizable Subjects: A Pilot Study, Isotani T, Lehmann D, Pascual-Marqui RD, Kochi K, Wackermann J, Saito N, Yagyu T, Kinoshita T, Sasada K., Neuropsychobiology 2001;44(4):192-8
      8. Riddled Basins And Unstable Dimension Variability In Chaotic Systems With And Without Symmetry, Ricardo L. Viana, Celso Grebogi, Int. J. of Bifurcation and Chaos, Vol. 11, No. 10 (2001) 2689-2698
      9. Rapid Increase in Clusters of Presynaptic Proteins at Onset of Long-Lasting Potentiation, Antonova, Irina, Arancio, Ottavio, Trillat, Anne-Cecile, Wang, Hong-Gang, Zablow, Leonard, Udo, Hiroshi, Kandel, Eric R., Hawkins, Robert D, Science 2001 294: 1547-1550
      10. Condensed-Matter Physics: Dressing Up Bare Particles, Hartmut Haug, Nature 414, 261 - 262 (2001)
      11. Small-Scale Structure Of Nonlinearly Interacting Species Advected By Chaotic Flows,, Emilio Hernandez-Garcia, Cristobal Lopez, Zoltan Neufeld, arXiv. Paper ID: nlin.CD/0111033 . 01/11/14
      12. Double Mutant Gene Eliminates Malaria Risk, James Randerson, New Scientist, 01/11/14
      13. Statistics Of Some Low-Dimensional Chaotic Flows, Elena S. Dimitrova And Oleg I. Yordanov, Int. J. of Bifurcation and Chaos,Vol. 11, No. 10 (2001) 2675-2682
      14. Only Time Will Tell: Clock Drawing As An Early Indicator Of Neurological Dysfunction, J. Shah, P&S Medical Review, Columbia University College of Physicians and Surgeons, pp 30-34 Spring 2001


    2. Conference Announcements Bookmark and Share

      1. America's Secret Weapon, Business 2.0 Live! Event, Stanford, 01/11/28
      2. II World Congress of Citizens Networks, Buenos Aires, Argentina, 01/12/05-07
      3. "Horizons In Complex Systems" in honor of H. Eugene Stanley's 60th birthday, Univ. Messina, Sicily, 01/12/05-08
      4. America's Secret Weapon, Business 2.0 Live! Event, Stanford, 01/12/07
      5. From Worker to Colony: Understanding the Organisation of Insect Societies, Isaac Newton Institute, Cambridge, UK. , 01/12/07-08
      6. Intl Conf on Current Trends In Differential Equations And Dynamical Systems, Kanpur, India, 01/12/15-17
      7. Complex Systems, Modeling Nonlinear Natural and Human Systems, Hawaii International Conference On System Sciences, HICSS-35, Hawaii, 02/01/07-10
      8. 1st Biennial Seminar on Philosophical, Methodological & Epistemological Implications of Complexity Theory, La Habana, Cuba, 02/01/07-11
      9. Topics in Nonlinear Dynamics, Collective Phenomena and Complexity: Dynamical Model Formulation, Analysis and Symmetry, Canberra, Australia, 02/01/21-02/01
      10. AIS'2002: Towards Component-Based Modeling and Simulation, Lisbon, Portugal, 02/04/07-10
      11. World Conference NL 2002 - Networked Learning in a Global Environment: Challenges and Solutions for Virtual Education, Berlin, Germany, 02/05/01-04
      12. International Conference on Complex Systems (ICCS2002), Nashua, NH, 02/06/9-14
      13. 7th International Conference on Music Perception & Cognition - ICMPC7, Sydney, 02/07/17-21
      14. Self-Organisation and Evolution of Social Behaviour, Monte Verità, Switzerland, 02/09/08-13
      15. 3rd Intl NAISO Symposium on Engineering Of Intelligent Systems (EIS 20020), Malaga, Spain, 02/09/24-27
      16. Artificial Life VIII, UNSW, Sydney, Australia, 02/12/09-13


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