Complexity Digest 2001.04 January-22-2001

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"I think the next century will be the century of complexity." Stephen Hawking


  1. Right Side Of Brain May Be Key To Recognizing Yourself, Beth Israel Deac. Med. Cntr/Science Daily
    1. 'I' Is To The Right, NSU
    2. Self-Recognition And The Right Hemisphere, Nature
  2. Web Sites Begin to Self Organize, NYTimes
  3. A Model For The Emergence Of Cooperation, PNAS
  4. Scientists Bring Light to Full Stop, NYTimes
    1. Researchers Trap Light, Quantum Internet In Sight, Boston Herald
  5. The Capacity Of Wireless Communications, Nature
    1. Exploiting The Reflection Of Radio Waves, New Scientist
    2. Information Goes Round The Bend, Nature
  6. How Rain Pulses Drive Biome Growth, Science
    1. Variation Among Biomes in Temporal Dynamics of Aboveground Primary Production, Science
  7. Farming without a plow?, New Scientist
  8. Entanglement in a Quantum-Dot Molecule
  9. Coarse-Graining And Self-Similarity Of Price Fluctuations, arXiv
  10. The Leverage Effect In Financial Markets: Retarded Volatility And Market Panic, arXiv
  11. Dynamics Of Directed Graphs: The World-Wide Web, arXiv
  12. New Solution To Traveling Salesman Problem, WUSTL/Science Daily
  13. Predictability: A Way To Characterize Complexity, arXiv
  14. Quality of Informed Consent, J. Natl. Cancer Inst.
  15. A Default Mode Of Brain Function, PNAS
  16. Links & Snippets
    1. Pupalert
    2. Announcements


  1. Right Side Of Brain May Be Key To Recognizing Yourself, Beth Israel Deac. Med. Cntr/Science Daily

    Excerpt: The right side of the brain helps people recognize themselves in a picture, say researchers at Beth Israel Deaconess Medical Center in Boston.

    The study joins a growing body of evidence that demonstrates the right hemisphere plays an important role in self-awareness, which scientists believe is one aspect of human consciousness. The research is published in the Jan. 18 issue of the weekly journal Nature.

    "It's not an all or nothing phenomenon, but recognizing one's own face appears to be a preferential ability of the right hemisphere," says lead author Julian Keenan, Ph.D., a cognitive psychologist who did the work as a postdoctoral fellow at Beth Israel Deaconess. Keenan is now on a leave of absence from Beth Israel Deaconess and Harvard Medical School, where is is an instructor of neurology. He is working as a visiting scientist in another lab.

    In the first part of the study, Keenan and his colleagues worked with five patients who were undergoing preoperative testing for brain surgery to treat epilepsy. In the testing, each half of the brain was briefly anesthetized for up to three minutes so that surgeons could evaluate whether the right or left hemisphere was dominant for speech and memory.

    Each patient was shown and asked to remember a morphed computer image blending the patient's own face with the face of a famous person. Each man's photograph was morphed with the face of Bill Clinton or Albert Einstein, and each woman's was combined with the face of Marilyn Monroe or Princess Diana. After the anesthesia wore off, patients were asked to choose which face they remembered seeing, their face or the famous face, although they saw only the morphed image when they were under anesthesia.

    While the left hemispheres of the five patients were anesthetized, their right brains could apparently recognize themselves in the morphed images, says Keenan. Once the anesthesia wore off, all five patients remembered seeing their own faces. But after numbing of right hemisphere (and after the left hemisphere "saw" the morphed image), four out of five patients only remembered seeing the famous person.

    In a follow-up experiment, 10 healthy people who worked in the Beth Israel Deaconess neurology department each viewed a morphed image of his or her face with the face of a famous person and another one morphing a colleague's familiar face with a famous face. Using transcranial magnetic stimulation applied to the motor cortex near the front of each hemisphere, researchers found significantly greater right brain activity when people viewed a self-morph compared to a co-worker-morph. No such difference was seen when testing the left hemisphere, as measured by sensitive detectors on small tell-tale muscles on the back of each hand.

    "One of the astonishing findings in psychology is that humans and the apes (including chimpanzees, orangutans, and some gorillas) are the only species that recognize their own faces in a mirror," says Keenan, who began researching self-awareness as a graduate student. "It has been thought that this ability is a hallmark of consciousness. To know that our own face is ours inevitably requires a knowledge of the self. Without self-knowledge, it would be seemingly impossible to recognize who we are."

    Scientists believe studies of self-awareness may provide unique insights into consciousness. Doctors hope eventually to use such information to help people with disorders that include a lack of awareness of self and others, such as schizophrenia, autism and depersonalization syndrome.

    'I' Is To The Right, NSU

    Excerpt: "It is conceivable that a right-hemisphere network gives rise to self-awareness which may be a hallmark of higher-order consciousness," Keenan's team concludes.

    "Self-awareness, consciousness and mind are an expression of the same underlying process," agrees Gordon G. Gallup, who works on self-awareness in animals at the State University of New York." At about the time that children learn to recognize themselves, they begin to show other evidence of self-conception, such as using personal pronouns, smiling after mastering a task and engaging in self-conscious play."

    Self-Recognition And The Right Hemisphere, Nature

    Abstract: Although monkeys can perceive complex stimuli such as faces, only the higher apes are capable of recognizing their own face in a mirror. Here we show that in humans the right hemisphere of the brain seems to be preferentially involved in self-face recognition. Our findings indicate that neural substrates of the right hemisphere may selectively participate in processes linked to self-awareness.

  2. Web Sites Begin to Self Organize, NYTimes

    Excerpts: The Vines is an example of an emerging class of what are called self-organizing Web sites. Such sites are demonstrating that with a dab or two of well-written code and a bit of careful planning, a site can take a random collection of links or posts and turn them into a sophisticated, adaptive system. (...)

    Most efforts at self-organization so far have been fairly simple, but effective. Several features on Amazon.com, like the list of authors with books similar (...)

  3. A Model For The Emergence Of Cooperation, PNAS

    Abstract: Evolution produces complex and structured networks of interacting components in chemical, biological, and social systems. We describe a simple mathematical model for the evolution of an idealized chemical system to study how a network of cooperative molecular species arises and evolves to become more complex and structured. The network is modeled by a directed weighted graph whose positive and negative links represent "catalytic" and "inhibitory" interactions among the molecular species, and which evolves as the least populated species (typically those that go extinct) are replaced by new ones. A small autocatalytic set, appearing by chance, provides the seed for the spontaneous growth of connectivity and cooperation in the graph. A highly structured chemical organization arises inevitably as the autocatalytic set enlarges and percolates through the network in a short analytically determined timescale. This self organization does not require the presence of self-replicating species. The network also exhibits catastrophes over long timescales triggered by the chance elimination of "keystone" species, followed by recoveries.

  4. Scientists Bring Light to Full Stop, NYTimes

    Excerpts: "Essentially, the light becomes stuck in the medium, and it can't get out until the experimenters say so," said Dr. Seth Lloyd (¡­)

    "Who ever thought that you could make light stand still?"

    He said the work's biggest impact could come in futuristic technologies called quantum computing and quantum communication. Both concepts rely heavily on the ability of light to carry so-called quantum information, involving particles that can exist in many places or states at once.

    Researchers Trap Light, Quantum Internet In Sight, Boston Herald

    Excerpts: Observers say this ability to capture and release a complex light burst has tremendous potential for the evolution of a new generation of super-fast computers.

    ``It's a big step,'' said MIT physicist and engineer Seth Lloyd, who is developing primitive quantum computers in which information is stored on atoms.

    (¡­) That would vastly increase a computer's ability to perform complex operations.

    For Internet users, it could improve security and speed up search engines and other functions.

  5. The Capacity Of Wireless Communications, Nature

    Excerpt:   In either case, the relevant signal processing techniques come under the heading of 'multiple-input/multiple-output' communications, because multiple antennae are required to access the polarization or spatial channels. Here we show that, in a scattering environment, an extra factor of three in channel capacity can be obtained, relative to the conventional limit using dual-polarized radio signals. The extra capacity arises because there are six distinguishable electric and magnetic states of polarization at a given point, rather than two as is usually assumed.

    Exploiting The Reflection Of Radio Waves, New Scientist

    Excerpt: The scattering also allows the magnetic fields associated with the radio waves to carry information in all three directions; normally they contain no information not already carried by the electric field.

    So the team built such equipment and for both the transmitter and receiver, they connected three antennae together at right angles to each other. By sending separate signals to each of the antennae of the transmitter, they found they could beam radio waves polarized in three dimensions.

    Information Goes Round The Bend, Nature

    Excerpt:  But the scattering of the radio waves can be used to advantage. It means that in general the signal arrives at the receiver from all directions. Thus, three mutually perpendicular antennas can each pick up a signal.

    The researchers show that if such a set of antennas are used to transmit polarized signals, each of which consists of the two polarization states for each direction, then a similar trio of antennas can receive and distinguish the separate signals as they arrive after being reflected from surrounding objects.

  6. How Rain Pulses Drive Biome Growth, Science

    Summary: Understanding the patterns and mechanisms of ecosystem responsiveness to climate variability is fundamental to any attempt to predict ecosystem response to climate change. Traditional views of plant production in ecosystems have held that interannual variability of production should correlate directly with variability in precipitation. A long-term study of 14 different ecosystems in the United States, spanning a range of precipitation from 250 to 1400 millimeters per year, indicates that the pattern is more complex. Knapp and Smith (p. 481; see the news story by Kaiser) show that variability among years in production is not associated with variability in precipitation, and that the sites with the highest variability in precipitation do not exhibit the highest variation in production. They propose that the variability in production depends on an interaction between precipitation and growth potential of plants. 

    Excerpts: Most ecologists trying to picture how climate change will remold the world's ecosystems have been fixated on temperature. (..) But these ecological modelers haven't factored in the dramatic changes in storm frequency--and the droughts and heavier rains and snows those changes will bring to some regions--also predicted in a greenhouse world.(¡­) This new research finds that some ecosystems respond much more strongly than others to pulses in rainfall, which can spur surprisingly dramatic bursts in plant growth.

    Variation Among Biomes in Temporal Dynamics of Aboveground Primary Production, Science

    Excerpt: The greatest interannual variability in ANPP [aboveground net primary production] occurred in grasslands and old fields, with forests the least variable. At a continental scale, ANPP was strongly correlated with annual precipitation. However, interannual variability in ANPP was not related to variability in precipitation. Instead, maximum variability in ANPP occurred in biomes where high potential growth rates of herbaceous vegetation were combined with moderate variability in precipitation. In the most dynamic biomes, ANPP responded more strongly to wet than to dry years.

  7. Farming Without A Plow?, New Scientist

    Excerpts: Farmers across the developing world are throwing away their ploughs in a dramatic example of "sustainable" farming, a practice that is now sending crop yields soaring on millions of farms. (¡­)

    Sustainable agriculture deliberately lowers manmade inputs such as chemicals, while maximising nature's input. It replaces fertilisers with plants that fix nitrogen in the soil and pesticides with natural enemies of pests.(¡­)

    Besides relieving them of one of the most tedious jobs on the farm, abandoning the plough improves soil quality and raises crop yields. It even helps curb global warming by accumulating carbon in the soil.

  8. Entanglement in a Quantum-Dot Molecule, Science

    Summary: Potential solid-state schemes for quantum computing are of interest because these implementations offer the possibility of scale-up and integration. Bayer et al. (p. 451) describe results on a vertically coupled pair, or molecule, of single quantum dots. Under optical excitation and an applied electric field, a coupled electron-hole pair (exciton) is created on the molecule with just four possible arrangements for the electron-hole pair. When the dots are coupled, the excitation spectrum differs from those for the single dots. Entanglement between these possible exciton states manifests itself as an energy splitting in the excitation spectrum. Moreover, the energy splitting increased to 40 millielectron volts as the dot separation was reduced to 4 nanometers, which indicates that room-temperature operation may be possible.

    Abstract: We demonstrate coupling and entangling of quantum states in a pair of vertically aligned, self-assembled quantum dots by studying the emission of an interacting electron-hole pair (exciton) in a single dot molecule as a function of the separation between the dots. An interaction-induced energy splitting of the exciton is observed that exceeds 30 millielectron volts for a dot layer separation of 4 nanometers. The results are interpreted by mapping the tunneling of a particle in a double dot to the problem of a single spin. The electron-hole complex is shown to be equivalent to entangled states of two interacting spins.

  9. Coarse-Graining And Self-Similarity Of Price Fluctuations, arXiv

    Abstract: We propose a new approach for analyzing price fluctuations in their strongly correlated regime ranging from minutes to months. This is done by employing a self-similarity assumption for the magnitude of coarse-grained price fluctuation or volatility. The existence of a Cramer function, the characteristic function for self-similarity, is confirmed by analyzing real price data from a stock market. We also discuss the close interrelation among our approach, the scaling-of-moments method and the multifractal approach for price fluctuations.

  10. The Leverage Effect In Financial Markets: Retarded Volatility And Market Panic, arXiv

    Abstract: We investigate quantitatively the so-called leverage effect, which corresponds to a negative correlation between past returns and future volatility. For individual stocks, this correlation is moderate and decays exponentially over 50 days, while for stock indices, it is much stronger but decays faster. For individual stocks, the magnitude of this correlation has a universal value that can be rationalized in terms of a new `retarded' model which interpolates between a purely additive and a purely multiplicative stochastic process. For stock indices a specific market panic phenomenon seems to be necessary to account for the observed amplitude of the effect.

  11. Dynamics Of Directed Graphs: The World-Wide Web, arXiv

    Abstract: We introduce and simulate a growth model of the world-wide Web based on the dynamics of outgoing links that is motivated by the conduct of the agents in the real Web to update outgoing links (re)directing them towards constantly changing selected nodes. Emergent statistical correlation between the distributions of outgoing and incoming links is a key feature of the dynamics of the Web. The growth phase is characterized by temporal fractal structures which are manifested in the hierarchical organization of links. We obtain quantitative agreement with the recent empirical data in the real Web for the distributions of in- and out-links and for the size of connected component. In a fully grown network of N nodes we study the structure of connected clusters of nodes that are accessible along outgoing links from a randomly selected node. The distributions of size and depth of the connected clusters with a giant component exhibit supercritical behavior. By decreasing the control parameter---average fraction b of updated and added links per time step---towards bc(N) < 10% the Web can resume a critical structure with no giant component in it. We find a different universality class when the updates of links are not allowed, i.e., for b ~0, corresponding to the network of science citations.

  12. New Solution To Traveling Salesman Problem, WUSTL/Science Daily

    Excerpt: (...) Beyond the phone booth problem, the Zhang algorithm and the otherswere tested on a category called "No-wait flowshop problems." Picture an automobile paint shop with multiple stations for painting different portions of a car. The algorithm maps the most efficient route from start-to-finish. Also computed were routes for tiny disk drive readers inside a computer and routes for moving heavy oil-drilling equipment on a large field. In the case of the disk drive reader, a short route must be chosen to minimize the distances that the reader must "travel" to speed up data access operations. In the case of the drilling equipment, a short route means a short "travel" distance for the equipment. The algorithm also can be applied to what is called very large scale integration (VLSI). For such a problem, a route is needed that will connect all the minuscule components on a computer chip so that they can interface and function together.

    Each of the TSPs tested are considered asymmetrical, which takes into account that the distance from place A to place B is not the same as that from B to A. Asymmetrical problems more closely reflect real-world situations. For instance, traveling on a freeway, you might be able to get on and reach a destination without paying a toll, but on the way back you might have to cross a bridge that has a toll. Thus, the cost in one direction is not the same as that going back. The Zhang algorithm factors in these real-life asymmetries. The results of the research were presented Jan. 5, 2001, at the Third Workshop on Algorithm Engineering and Experiments (Alenex 01), held at Washington, D.C. Some of the results also will be included as a chapter in a forthcoming book on the Traveling Salesman Problem. The work is partially funded by the National Science Foundation. "The Traveling Salesman Problem is one of the first computer science problems to be approached in the past century, and it is one of the first problems shown to be in the class called NP-Complete," saidZhang.

    Loosely speaking, NP-Complete is a class of problems that are believed unsolvable within a reasonable amount of time in the worst case. Thus, approximation algorithms are very important for solving real-world problems such as the payphone coin collector problem. Zhang's algorithm is considered to be one of the two best approximation algorithms for the Asymmetric Traveling Salesman Problem. The other is what is called the Kanellakis-Papdimitrious local search algorithm, named after two noted computer scientists.

    Algorithms such as Zhang's are memory-efficient and meant to be embedded in hardware as a small but essential part of what's called mechanical electronic manufactured systems (MEMs). Zhang currently is working on algorithms that are meant to run on smart devices, with very small memory and limited power.

    "Memory is a very big issue today," Zhang said. "With MEMs, you bundle the software so it's very tightly integrated with the hardware and each smart device, with just a few thousand bits of memory and small amounts of data, all connect with each other to build and run a larger application. Running time-and space-efficient algorithms, you build a big system out of these small smart devices." Zhang also is working on efficient search algorithms for analyzing biological data such as DNA, RNA and protein sequences. He is particularly interested in applying his skills in computer science and artificial intelligence to a relatively new but very active area called computational biology, or bioinformatics.

    "If we say that information and computer technology were the leaders in the technology world in the last century, then biology will be the leader of this century," said Zhang. "The combination of information technology and biology will not only provide us the knowledge of life science, but also help to cure diseases and make our lives wonderful to live."

  13. Predictability: A Way To Characterize Complexity, arXiv

    Abstract: Different aspects of the predictability problem in dynamical systems are reviewed. The deep relation among Lyapunov exponents, Kolmogorov-Sinai entropy, Shannon entropy and algorithmic complexity is discussed. In particular, we emphasize how a characterization of the unpredictability of a system gives a measure of its complexity. Adopting this point of view, we review some developments in the characterization of the predictability of systems showing different kind of complexity: from low-dimensional systems to high-dimensional ones with spatio-temporal chaos and to fully developed turbulence. A special attention is devoted to finite-time and finite-resolution effects on predictability, which can be accounted with suitable generalization of the standard indicators. The problems involved in systems with intrinsic randomness is discussed, with emphasis on the important problems of distinguishing chaos from noise and of modeling the system. The characterization of irregular behavior in systems with discrete phase space is also considered.

  14. Quality of Informed Consent, J. Natl. Cancer Inst.

    Abstract: Background: The informed consent of participants is ethically and legally required for most research involving human subjects. However, standardized methods for assessing the adequacy of informed consent to research are lacking. Methods and Results: We designed a brief questionnaire, the Quality of Informed Consent (QuIC), to measure subjects' actual (objective) and perceived (subjective) understanding of cancer clinical trials. The QuIC incorporates the basic elements of informed consent specified in federal regulations, assesses the therapeutic misconception (the belief that all aspects of a clinical trial are designed to directly benefit the subject), and employs the language and structure of the new National Cancer Institute template for informed consent documents. We modified the QuIC after receiving feedback from pilot tests with cancer research subjects, as well as validation from two independent expert panels. We then sent the QuIC to 287 adult cancer patients enrolled on phase I, II, or III clinical trials. Two hundred seven subjects (72%) completed the QuIC. To assess test¨Cretest reliability, a random sample of 32 respondents was selected, of whom 17 (53%) completed the questionnaire a second time. The test¨Cretest reliability was good with intraclass correlation coefficients of .66 for tests of objective understanding and .77 for tests of subjective understanding. The current version of the QuIC, which consists of 20 questions for objective understanding and 14 questions for subjective understanding, was tested for time and ease of administration in a sample of nine adult cancer patients. The QuIC required an average of 7.2 minutes to complete. Conclusions: The QuIC is a brief, reliable, and valid questionnaire that holds promise as a standardized way to assess the outcome of the informed consent process in cancer clinical trials.

  15. A Default Mode Of Brain Function, PNAS

    Excerpt: A baseline or control state is fundamental to the understanding of most complex systems. Defining a baseline state in the human brain, arguably our most complex system, poses a particular challenge. Many suspect that left unconstrained, its activity will vary unpredictably. Despite this prediction we identify a baseline state of the normal adult human brain in terms of the brain oxygen extraction fraction or OEF. (¡­)

    These decreases suggest the existence of an organized, baseline default mode of brain function that is suspended during specific goal-directed behaviors.

    • A Default Mode Of Brain Function, Marcus E. Raichle, Ann Mary MacLeod, Abraham Z. Snyder, William J. Powers, Debra A. Gusnard, and Gordon L. Shulman, Proc. Natl. Acad. Sci. USA 2001 January 16; 98(2): p. 676-682
  16. Links & Snippets
    Pub Alert: These references can be found in http://www.thescientificworld.com/. To retrieve the articles connect to the site and search for the title.
    • Age estimation of the mid-Pleistocene microtektite event in the South China Sea: A case showing the complexity of the sea-land correlation, Wang, J.; Zhao, Q.; Cheng, X.; Wang, R.; Wang, P., CHINESE SCIENCE BULLETIN -ENGLISH EDITION-
    • Sequence Complexity of Disordered Protein, Romero, P.; Obradovic, Z.; Li, X.; Garner, E. C.; Brown, C. J.; Dunker, A. K., PROTEINS -NEW YORK-
    • Computational Complexity of Finding Highly Co-occurrent Itemsets in Market Basket Databases, Kwon, Y.-D.; Ishihara, Y.; Shimizu, S.; Ito, M., IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E SERIES A
    • Collective Processes in Complex Plasmas, Shukla, P. K., AIP CONFERENCE PROCEEDINGS
    • Complex Macromolecular Architectures by Combining TEMPO Living Free Radical and Anionic Polymerization, Tsoukatos, T.; Pispas, S.; Hadjichristidis, N., MACROMOLECULES
    • Becoming a Leader in a Complex Organization, Denis, J.-L.; Langley, A.; Pineault, M., JOURNAL OF MANAGEMENT STUDIES -OXFORD-
    • A Nonlinear Simulation on Beam-Wave Interaction for High-Harmonic Complex Cavity Gyrotron with Gradual Transition, Sheng, Y.; Hong-fu, L.; Zhong-lian, X.; Yong, L., ACTA PHYSICA SINICA -CHINESE EDITION-
    • Irregularities of Distribution, Derandomization, and Complexity Theory, Chazelle, B., LECTURE NOTES IN COMPUTER SCIENCE
    • Analysis of postural sway using entropy measures of signal complexity, Sabatini, A. M., MEDICAL AND BIOLOGICAL ENGINEERING AND COMPUTING
    • On new approaches in nonlinear dynamics of complex systems, Kurakin, P.; Malinetsky, G.; Podlazov, A., MACROMOLECULAR SYMPOSIA
    • Language Variation and Complexity, Pishwa, H., ANGLIA -TUBINGEN- ZEITSCHRIFT FUR ENGLISCHE PHILOLOGIE-
    • Symmetry, Singularities, and Integrability in Complex Dynamics II. Rescaling and Time-Translation in Two-Dimensional Systems, Leach, P. G. L.; Cotsakis, S.; Flessas, G. P., JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
    • Small enterprises as complex adaptive systems: a methodological question?, Fuller, T.; Moran, P., ENTREPRENEURSHIP AND REGIONAL DEVELOPMENT
    • Computer-aided production management issues in the engineer-to-order production of complex capital goods explored using a simulation approach, Hicks, C.; Braiden, P. M., INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH
    • Discrimination of Speech and of Complex Nonspeech Sounds of Different Temporal Structure in the Left and Right Cerebral Hemispheres, Shtyrov, Y.; Kujala, T.; Palva, S.; Ilmoniemi, R. J.; Naatanen, R., NEUROIMAGE
    • Nest mate recognition in ants with complex colonies: within- and between-population variation, Stuart, R. J.; Herbers, J. M., BEHAVIORAL ECOLOGY
    • Numerical simulation of wind system over complex terrain near shoreline, Ohya, Y.; Uchida, T.; Koterayama, W., PROCEEDINGS OF THE TECHNO OCEAN SYMPOSIUM

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