Complexity Digest 2001.49

03-Dec-2001

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Content

  1. Reinventing The Wheel, Time.com
  2. Complexity: An Appropriate Framework For Development?, Progress in Development Studies, Progress in Development Studies
  3. Friends Are Stranger Than Strangers, Nature
  4. Tapping Into mRNA Export, Science
    1. Delineation of mRNA Export Pathways by the Use of Cell-Permeable Peptides, Science
  5. Can Generalist Predators Be Effective Biocontrol Agents?, Annu. Rev. Entomol.
  6. Twin Gene Idea Could Wipe Out Malaria Mosquito, New Scientist
  7. Interactive Memory Systems In The Human Brain, Nature
  8. A Self-Organizing Neural Network Model Of The Acquisition Of Word Meaning, CogPrints
  9. Visual Stimuli Activate Auditory Cortex In The Deaf, Nature Neuroscience
  10. Perception, Attention, And Memory, Neuroscience and Biobehavioural Reviews
    1. Now You See It, Now You Don't, Neuroscience & Biobehavioral Reviews
  11. Do Apes Share The "Language Organ"?, Science Now
    1. Asymmetric Broca's Area In Great Apes, Nature
  12. Neural Prosthetics And Direct Neural Control, Stanford Univ/Kurzweil AI.net
  13. Hand Synergies During Reach-To-Grasp, Neurophysiol
  14. Whales Show The Way To A Cleaner, Greener Boat, New Scientist
  15. Scientists Raise Spectre Of Gene-Modified Athletes, New Scientist
  16. Tiny Black Holes May Be Exploding In Our Cosmic Backyard, New Scientist
  17. Nanotubes Hint At Room Temperature Superconductivity, New Scientist
  18. Volunteers Help Find A New Prime [Number, Ed.], Science Now
  19. Complex Challenges: Global Terrorist Networks
    1. Ames Strain Of Anthrax Limited To Few Labs, The Washington Post
    2. New Perspectives on Conventional Military Force and the War on Terrorism, Postponed!
    3. War May be Costing $1 Billion a Month, AP/excite News
    4. Estimated Cost of Operation Enduring Freedom, CSBA
    5. 3 U.S. Troops Killed in Afghanistan, AP/excite News, 01/12/05
  20. Links & Snippets
    1. SFI Working Papers
    2. Other Papers
    3. Conference Announcements

  1. Reinventing The Wheel, Time.com Next Article Bookmark and Share

    Editor's Note: That this invention happens in the year 2001 is very timely, since it really could potentially change the world in a way cars have changed the human transportation system and city structure in the beginning of the previous century. On the other hand -as the author points out- our society is immensely more complex in the year 2001 than it was back in 1901 and there are many scenarios in which Ginger could go the way of the beta video format and cars could play the role of the "QWERTY"-keyboard of the 21st century. The impact on the global environment, however, would be much more severe especially when China decides which route to take in personal transport. On the other hand, Calcutta already has an urban transportation system with high mobility, safety, and intelligence: the human powered rickshaw system. (see ComDig01-13).

    Excerpt: "When you walk, you're really in what's called a controlled fall. You off-balance yourself, putting one foot in front of the other and falling onto them over and over again. In the same way, when you use a Segway, there's a gyroscope that acts like your inner ear, a computer that acts like your brain, motors that act like your muscles, wheels that act like your feet. Suddenly, you feel like you have on a pair of magic sneakers, and instead of falling forward, you go sailing across the room."


  2. Complexity: An Appropriate Framework For Development?, Progress in Development Studies, Progress in Development Studies Next Article Bookmark and Share

    Excerpts: A family of nonlinear systems (...) variously described as being complex, because they have numerous internal elements, dynamic, because their behaviour is governed by local interactions between the elements; and dissipative, because they have to consume energy to avoid drifting from self-organization into [microscopic, thermodynamic, Ed.] chaos. When such systems are capable of evolution they are also known as Complex Adaptive Systems. To describe complex systems and consider their relevance to development it is necessary first to understand three regimes of behaviour, order, chaos and self-organized complexity.

  3. Friends Are Stranger Than Strangers, Nature Next Article Bookmark and Share

    Excerpts: The problem, says Newman, arises from the assumption that we are average members of the population who know other average people. (…)

    Newman finds that a small number of people with a large number of friends skews the network relative to one made up of uniformly 'average' people.

    He has devised a mathematical approximation for coping with these biases. It makes a more accurate estimate of the number of 'friends of friends' that fall into a particular subset of the population.


  4. Tapping Into mRNA Export, Science Next Article Bookmark and Share

    Excerpt: For researchers trying to elucidate how one protein activity or intermolecular interaction contributes to a complex metabolic pathway, a specific chemical inhibitor can be an invaluable tool. Yet, in living cells, disrupting a single activity is often insufficient to elicit a discernible response. The reason is that many metabolic pathways exhibit functional redundancy--that is, they are made up of multiple interwoven activities that can, at least in part, compensate for one another. Deconvoluting the intricacies of such redundant pathways usually requires disrupting two or more activities at once.

    1. Delineation of mRNA Export Pathways by the Use of Cell-Permeable Peptides, Science Next Article Bookmark and Share

      Excerpt: The transport of messenger RNAs (mRNAs) from the nucleus to the cytoplasm involves adapter proteins that bind the mRNA as well as receptor proteins that interact with the nuclear pore complex. We demonstrate the utility of cell-permeable peptides designed to interfere with interactions between potential adapter and receptor proteins to define the pathways accessed by particular mRNAs. We show that HuR, a protein implicated in the stabilization of short-lived mRNAs containing AU-rich elements (AREs), serves as an adapter for c-fos mRNA export through two pathways.


  5. Can Generalist Predators Be Effective Biocontrol Agents?, Annu. Rev. Entomol. Next Article Bookmark and Share

    Excerpts: Theoretical developments are helping us to comprehend the basic parameters governing the dynamics of the interactions between generalist predators and their many pest and nonpest prey. In practice, however, inter- and intraspecific interactions between generalist predators, and between the predators and their prey, within multispecies systems under the influence of rapidly changing biotic and abiotic variables are difficult to predict. (…) We now need to find ways of disentangling the factors influencing positive and negative interactions within natural enemy communities in order to optimize beneficial synergies leading to pest control.

  6. Twin Gene Idea Could Wipe Out Malaria Mosquito, New Scientist Next Article Bookmark and Share

    Excerpts: Every 10 seconds a child dies from malaria - but there may now be a way to control the Anopheles mosquito that spreads the disease.

    Scientists say they can genetically modify whole mosquito populations so that the flies are either susceptible to pesticides, or can't transmit the malaria parasite. And they would only need to release relatively few GM mosquitoes to kick-start the process.

    According to the WHO, malaria claims more lives than any other communicable disease except tuberculosis, infecting around 500 million people each year.


  7. Interactive Memory Systems In The Human Brain, Nature Next Article Bookmark and Share

    Excerpt: Learning and memory in humans rely upon several memory systems, which appear to have dissociable brain substrates. A fundamental question concerns whether, and how, these memory systems interact. Here we show using functional magnetic resonance imaging (FMRI) that these memory systems may compete with each other during classification learning in humans. The medial temporal lobe and basal ganglia were differently engaged across subjects during classification learning depending upon whether the task emphasized declarative or nondeclarative memory, even when the to-be-learned material and the level of performance did not differ.

  8. A Self-Organizing Neural Network Model Of The Acquisition Of Word Meaning, CogPrints Next Article Bookmark and Share

    Abstract: In this paper we present a self-organizing connectionist model of the acquisition of word meaning. Our model consists of two neural networks and builds on the basic concepts of Hebbian learning and self-organization. One network learns to approximate word transition probabilities, which are used for lexical representation, and the other network, a self-organizing map, is trained on these representations, projecting them onto a 2D space. The model relies on lexical co-occurrence information to represent word meanings in the lexicon. The results show that our model is able to acquire semantic representations from both artificial data and real corpus of language use. In addition, the model demonstrates the ability to develop rather accurate word representations even with a sparse training set.

  9. Visual Stimuli Activate Auditory Cortex In The Deaf, Nature Neuroscience Next Article Bookmark and Share

    Abstract: Previous brain imaging studies have demonstrated responses to tactile and auditory stimuli in visual cortex of blind subjects, suggesting that removal of one sensory modality leads to neural reorganization of the remaining modalities. To investigate whether similar 'cross-modal' plasticity occurs in human auditory cortex, we used functional magnetic resonance imaging (fMRI) to measure visually evoked activity in auditory areas of both early-deafened and hearing individuals. Here we find that deaf subjects exhibit activation in a region of the right auditory cortex (¡K) demonstrating that early deafness results in the processing of visual stimuli in auditory cortex.

  10. Perception, Attention, And Memory, Neuroscience and Biobehavioural Reviews Next Article Bookmark and Share

    Contributing Editor's Note: The following work is introduction to cognitive neuroscience which links traditional physiological understanding to natural sciences and neural computation. Complex issues like perception, attention and memory are to be addressed from such interdisciplinary approach, the authors suggest. For example, when we hear a sound we pay 'attention' by tending to orient to the source of that sound. Macroscopic recordings give us only very limited information about how neuronal networks interact and the nature of the neural mechanisms. Here, according to the authors, computational modeling makes it possible to build and test circuits that simulate the neural interaction required for 'attentional' information processing. So, in this case, artificial neural network (ANN) modeling can give deeper insight.

    Excerpts: Event-related potentials (ERPs) in healthy subjects and in patients with focal lesions provided an important insight into neural mechanisms of attention and the brain areas required for selective processing.This is complemented and extended by imaging studies (¡K) to give us a better understanding of what areas in the brain are related to attentional information processing. A further clear example of the productive interactions that can occur between computational modelling and intracortical recordings in animals has arisen in connection with the temporal binding hypothesis (¡K) which proposes that synchronised neural activity is the key neural mechanism (¡K).


    1. Now You See It, Now You Don't, Neuroscience & Biobehavioral Reviews Next Article Bookmark and Share

      Contributing Editor's Note: What directs our attention is the question under study for recent past. With positron-emission tomography (PET) and functional magnetic resonance imaging (fMRI) techniques to look into the brain have helped such investigations. Following work is review of such works to find attentional control in the human brain. Spatial attention comes from visual information, but attention has the ability to operate on what "don't see it", that is non-spatial frameworks. Although, the author concludes that spatial attention play the fundamental role in guiding perception and action, non-spatial attention cannot downplay that role.

      Abstract: The brain areas implicated in the control of visual spatial attention were noted to resemble those involved in the control of eye movements, and direct experimental comparisons supported a tight link between the two systems. The findings suggested a sensible view of the attentional 'homunculus' as a distributed neural system related to the control of eye movements. Different parietal and frontal regions become engaged when attention is shifted along non-spatial dimensions, such as when attention is directed toward a particular motor act or toward a specific point in time. In these cases, the neural system resembles those involved in the control of limb movements. The attentional homunculus thus begins to dissolve.


  11. Do Apes Share The "Language Organ"?, Science Now Next Article Bookmark and Share

    Excerpt: Of the various traits separating people from other members of the animal kingdom, among the most striking is the use of language. Closely associated with this talent is a part of the brain called Brodmann's area 44, which in humans makes up part of the better known Broca's area. Now two scientists say they've discovered that Brodmann's area 44 in chimpanzees and gorillas resembles that of the human brain-a result leading them to propose that this part of the brain evolved for communication millions of years ago.

    1. Asymmetric Broca's Area In Great Apes, Nature Next Article Bookmark and Share

      Excerpt: Brodmann's area 44 delineates part of Broca's area within the inferior frontal gyrus of the human brain and is a critical region for speech production, being larger in the left hemisphere than in the right - an asymmetry that has been correlated with language dominance. Here we show that there is a similar asymmetry in this area, also with left-hemisphere dominance, in three great ape species (Pan troglodytes, Pan paniscus and Gorilla gorilla).


  12. Neural Prosthetics And Direct Neural Control, Stanford Univ/Kurzweil AI.net Next Article Bookmark and Share

    Excerpts: Reaching out to touch a dot on a computer screen may seem simple, but it requires a complex chain of signals that link together the eye, brain and arm. Damage to any part of that chain, such as a spinal injury, stroke or neurodegenerative disease, can make even the simplest tasks impossible. (…)

    The advantage of using planning cells is that they encode a simpler set of parameters than motor cells do. Whereas motor cells generate complex signals that control the three-dimensional path of an arm as it moves toward its target, planning cells encode primarily two parameters: where and when to move.


  13. Hand Synergies During Reach-To-Grasp, Neurophysiol Next Article Bookmark and Share

    Abstract: An emerging viewpoint is that the CNS uses synergies to simplify the control of the hand. Previous work has shown that static hand postures for mimed grasps can be described by a few principal components (...). Extending that earlier work, this study addressed whether the entire act of grasp can be described by a small number of postural synergies ["eigen-postures", Ed.]. (¡K) These findings suggest that much of reach-to-grasp is effected using a base posture with refinements in finger and thumb positions added in time to yield unique hand shapes.

  14. Whales Show The Way To A Cleaner, Greener Boat, New Scientist Next Article Bookmark and Share

    Excerpt: Baum and his team examined freeze-dried samples of pilot whale skin under a cryo-scanning electron microscope. They discovered a surface made up of tiny pores 0.1 micrometres across surrounded by raised "nanoridges".

    In between the ridges is a rubber-like gel containing enzymes that denature proteins and carbohydrates. The gel, which oozes out of the gaps between skin cells, is replenished as the whale sheds its skin.

    Baum thinks that organisms such as bacteria and diatoms have trouble sticking to the ridge edges, which provide little purchase.


  15. Scientists Raise Spectre Of Gene-Modified Athletes, New Scientist Next Article Bookmark and Share

    Excerpt: Gene doping, in which athletes could genetically modify themselves with performance enhancing DNA, will be almost impossible to detect according to Peter Schjerling at the Copenhagen Muscle Research Centre in Denmark.

    And far-fetched as it may seem, we may be watching genetically-modified (GM) athletes as soon as the Beijing Olympics in 2008, according to Charles Yesalis, an expert in performance enhancing drugs at Pennsylvania State University. The predictions are being presented at the Genes in Sport Conference at University College London on Friday.


  16. Tiny Black Holes May Be Exploding In Our Cosmic Backyard, New Scientist Next Article Bookmark and Share

    Excerpt: Tiny black holes may be detonating like time bombs all over our cosmic backyard. The explosions could explain a class of unusual energy bursts that have been picked up here on Earth, say physicists in the US.

    Gamma-ray bursts are spectacular releases of energy that for a few seconds can outshine everything else in the Universe. They can come from any part of the sky, and from this astronomers have concluded that they are produced at the very edge of the Universe, (…)


  17. Nanotubes Hint At Room Temperature Superconductivity, New Scientist Next Article Bookmark and Share

    Excerpt: Tiny tubes of carbon may conduct electricity without any resistance, at temperatures stretching up past the boiling point of water. The tubes would be the first superconductors to work at room temperature.

    Guo-meng Zhao and Yong Sheng Wang of the University of Houston in Texas found subtle signs of superconductivity. It wasn't zero resistance, but it's the closest anyone's got so far. "I think all the experimental results are consistent with superconductivity," Zhao says. "But I cannot rule out other explanations."


  18. Volunteers Help Find A New Prime [Number, Ed.], Science Now Next Article Bookmark and Share

    Excerpts: The discovery is the 39th known Mersenne prime, a set of numbers that are of the form 2p - 1, where p must also be a prime number. Because of that exponential 2p, Mersenne primes rapidly get very, very large. So when a project called the Great Internet Mersenne Prime Search (GIMPS) found the new number, nobody was surprised that it topped the scale. The previous record holder, 26,972,593 - 1, is more than 2 million digits long and was found by GIMPS two and a half years ago.

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

    Excerpt: Since the mid-1980s, the U.S. Army laboratory that is the main custodian of the virulent strain of anthrax used in the recent terrorist attacks distributed the bacteria to just five labs in the United States, Canada and England, according to government documents and interviews. Two of the labs -- both in the private sector -- received the strain this spring, only a few months before letters tainted with anthrax spores were mailed to New York and Washington, the records show. The documents, obtained by The Washington Post, offer the first official accounting of how the microbes, known as the Ames strain, were originally disseminated. They show that the distribution of Ames was much narrower than recently thought, and a top anthrax researcher said the strain may be limited to a dozen labs. (...)

    1. Ames Strain Of Anthrax Limited To Few Labs, The Washington Post Next Article Bookmark and Share


    2. New Perspectives on Conventional Military Force and the War on Terrorism, Postponed! Next Article Bookmark and Share

      Editor's Note: The workshop New Perspectives on Conventional Military Force and the War on Terrorism, originally to be held in Washington, DC next week needs to be postponed until spring 2002. In this workshop participants from academia, industry and government were to explore ways in which methods from complex systems could be applied to solve the problem of global terrorist networks. According to the organizer, the military funding for travel and conference participation was frozen and it would not make sense to hold the workshop without participation from the military.

      Viewing governments as complex adaptive systems, budgets are primary evolutionary fitness parameters that discriminate between competing programs and largely determine which ones will grow and which ones will go extinct. In regards to the declared goal of solving the problem of terrorism it remains to be seen if the multi-billion dollar expenses allocated to the bombing campaign in Afghanistan is indeed so much more effective than corresponding investments in human intelligence and innovative, complexity based strategies and efforts.

      "Still, parts of the war are adding up: the estimated $5,000 an hour to fly a Navy FA-18 fighter-bomber, the $25,600 cost of one of the frequently used Joint Direct Attack Munition bombs [the type of bomb that killed three U.S. troops earlier today (AP), Ed.], the top-of-the-line Tomahawk cruise missiles."

    3. War May be Costing $1 Billion a Month, AP/excite News Next Article Bookmark and Share

      War May be Costing $1 Billion a Month, AP/excite News, 01/11/11

    4. Estimated Cost of Operation Enduring Freedom, CSBA Next Article Bookmark and Share

      Estimated Cost of Operation Enduring Freedom, Steven M. Kosiak, Center for Strategic and Budgetary Assessments (CSBA), 01/11/02

    5. 3 U.S. Troops Killed in Afghanistan, AP/excite News, 01/12/05 Next Article Bookmark and Share

      3 U.S. Troops Killed in Afghanistan AP/excite News, 01/12/05

  20. Links & Snippets Next Article Bookmark and Share

    1. SFI Working Papers Next Article Bookmark and Share

      1. Topological Properties of Food Webs: From Real Data to Community Assembly Models, José M. Montoya and Ricard V. Solé, SFI WP 01-11-069
      > 2. Optimization in Complex Networks, Ramon Ferrer i Cancho and Ricard V. Solé, SFI WP 01-11-068
      > 3. Secondary Structure Prediction for Aligned RNA Sequences, Ivo l. Hofacker, Martin Fekete, and Peter F. Stadler, SFI WP 01-11-067
      > 4. Ego-Centered Networks and the Ripple Effect, M. E. J. Newman, SFI WP 01-11-066
      > 5. Self-organized Instability in Complex Ecosystems, Ricard V. Solé, David Alonso, and Alan McKane, SFI WP 01-11-065
      > 6. Decisionmetrics: A Decision-Based Approach to Econometric Modeling, Spyros Skouras, SFI WP 01-11-064
      > 7. Economic Man in Cross-Cultural Perspective: Behavioral Experiments in Fifteen Small-Scale Societies, Joseph Henrich, et. al., SFI WP 01-11-063
      > 8. Exploring the Evolution of Complexity in Signaling Networks, John H. Holland, SFI WP 01-10-062

    2. Other Papers Next Article Bookmark and Share

      1. Viral Infection: Live And Uncut
      2. Why Do Intranets Fail?, Daintry Duffy, 2001/11/01
      3. Study Shows Women More Susceptible To Damage From Ecstasy Drug, Reuters, 2001/11/29
      4. Systematic Distortions In World Fisheries Catch Trends, R Watson & D Pauly
      5. Demography Of The Endangered North Atlantic Right Whale, M Fujiwara & H Caswell
      6. Endocrine Insights Into The Evolution Of Metamorphosis In Insects, James W. Truman and Lynn M. Riddiford, Annu. Rev. Entomol, 2001/11/20
      7. Representation And Extrapolation In Multi-Layer Perceptrons, Browne, Antony, CogPrints, 2001
      8. Effects Of Common Excitatory And Inhibitory Inputs On Motor-Neuron Synchronization, K. S. Turker, R. K. Powers, J. Neurophysiol., 2001/12/1
      9. Short-Term Effects Of Exposure To Mobile Phones, A W Preece, G Iwi, A Davies Smith, K Wesnes, S Butler, E Lim, A Varey,Med. Phy, Bioengg., Univ. of Bristol
      10. Competitive Displacement Among Insects And Arachnids, Stuart R. Reitz, John T. Trumble, Annu. Rev. Entomol, 2001/11/20
      11. Bayesian Logic Programs, Kristian Kersting, Luc De Raedt, arXiv, 01/11/23
      12. 'Gene Gun' Blazes Away In Biotech Fight On Famine, Jeremy Smith, Reuters, 2001/11/17
      13. The Biology Of The Dance Language, Annu. Rev. Entomol, 2001/11/20
      14. Genetic Influences On Brain Structure, Nature Neuroscience, M. Migliore, L. Messineo, 2001/12
      15. Quantitative Modeling Of Perception And Production Of Time Intervals, M. Cardaci, G. F. Ayala, J. Neurophysiol, 2001/12/1

    3. Conference Announcements Bookmark and Share

      1. II World Congress of Citizens Networks, Buenos Aires, Argentina, 01/12/05-07
      2. "Horizons In Complex Systems" in honor of H. Eugene Stanley's 60th birthday, Univ. Messina, Sicily, 01/12/05-08
      3. America's Secret Weapon, Business 2.0 Live! Event, Stanford, 01/12/07
      4. From Worker to Colony: Understanding the Organisation of Insect Societies, Cambridge, UK., 01/12/07-08
      5. New Perspectives on Conventional Military Force and the War on Terrorism, Washington, DC, 01/12/11-13
      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. Physik Sozio-Oekonomischer Systeme, German Phys Soc, Regensburg, Germany, 02/03/11-15
      11. Capturing Business Complexity with Agent-Based Modeling and Simulation, Argonne National Laboratory, Il. 02/03/04-08
      12. AIS'2002: Towards Component-Based Modeling and Simulation, Lisbon, Portugal, 02/04/07-10
      13. World Conference NL 2002 - Networked Learning in a Global Environment: Challenges and Solutions for Virtual Education, Berlin, Germany, 02/05/01-04
      14. International Conference on Complex Systems (ICCS2002), Nashua, NH, 02/06/9-14
      15. International Conference SocioPhysics, ZIF - Bielefeld, Germany, 01/06/06-09
      16. 7th International Conference on Music Perception & Cognition - ICMPC7, Sydney, 02/07/17-21
      17. Self-Organisation and Evolution of Social Behaviour, Monte Verità, Switzerland, 02/09/08-13
      18. 3rd Intl NAISO Symposium on Engineering Of Intelligent Systems (EIS 20020), Malaga, Spain, 02/09/24-27
      19. ACRI 2002, 5th Intl Conf on Cellular Automata for Research and Industry, Geneva, Switzerland, 02/10/09-11
      20. Artificial Life VIII, UNSW, Sydney, Australia, 02/12/09-13

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