Complexity Digest 2003.33 August-18-2003
Archive: http://www.comdig.org, European Mirror: http://www.comdig.de
Asian Mirror: http://www.phil.pku.edu.cn/resguide/comdig/ (Chinese GB-Code)
"I think the next century will be the century of complexity." Stephen Hawking, 2000
Excerpts: While energy experts disagreed on the blackout's cause, they agreed that the failure betrayed the transmission system's age. (°≠)
With only a limited number of high-voltage lines, a power failure can spread more quickly when generators try to send their power to areas that need it, overloading the lines that remain. Generators are designed to switch off if their power cannot be transmitted, which is apparently what happened to dozens of turbines and nuclear plants around the northeast and upper Midwest today.
- Power Failure Reveals a Creaky System, Energy Experts Believe, David Firestone, Richard Perez-Pena, NYTimes, 030/8/14
Excerpts: The Department of Homeland Security said that it determined within an hour that Thursday's widespread power failure had not resulted from a terrorist attack. (°≠)
But the administration's upbeat appraisal of its performance was not shared by some counterterrorism and security experts, who said the blackout demonstrated that the government and private industry had not dealt with basic flaws in the nation's infrastructure since the 2001 attacks, and that terrorists would see new opportunities for attack.
- Agency Quickly Concludes No Terrorists Were Involved, Philip Shenon, NYTimes, 030/8/14
Excerpts: The regular public telephone network generally kept working after the power went out, but the cellular systems in affected areas were often unable to cope.
Wireless network operators said their networks were unable to handle the heavy traffic as large numbers of people simultaneously tried to reach friends, family and business associates. But the lack of electricity or the failure of backup power systems at cellular transmitter stations and traffic switching centers were also partly to blame.(°≠) the batteries may not last more than a few hours.
- When Wireless Phones Failed, Callers Turned to Land Lines, Matt Richtel, Simon Romero, NYTimes, 030/8/14
Excerpts: The Internet was for the most part performing normally, despite the power failure, a tracking firm said.
Internet performance tracker Keynote Systems said the outage has not slowed the Internet.
"At this time, 4:50 pm EDT, the Internet is performing normally and major Web sites in the U.S. are also performing normally, although a few of the news Web sites are showing slightly longer download times," Keynote spokesman Dan Berkowitz wrote in an e-mail.
- Internet Survives Power Failure, NEWS.com, 03/08/14
Excerpts: An enormous, instantaneous reversal of the power flow -(°≠) - overloaded one or more power lines, which quickly took themselves out of service.
In seconds, parallel lines were overloaded as well and shut themselves down, and then generating stations disconnected themselves. Ultimately, dozens of lines and about 100 power plants, with a staggering 61,800 megawatts of generation, had shut down - apparently before any human being could react. The series of major failures began about 4:08 p.m., (°≠) The failures were triggered by a few seconds of tremendous instability in energy flows.
- Experts Asking Why Problems Spread So Far, Matthew L. Wald, Richard Perez-Pena, Neela Banerjee, NYTimes, 030/8/14
Excerpts:The magnitude of the blackout is rooted in an often ignored aspect of our globalized world: vulnerability due to interconnectivity. (°≠)
In the early days of electricity, all power was produced locally.(°≠) Local generators had to satisfy the peak demands of hot summer nights, when everything from air-conditioners to televisions run full power. That means that the generators were idle most of the time outside of peak hours.(°≠)
. The current power grid linked up formerly isolated systems with enough wire to stretch to the moon and back.
Editor's Note: The German system has switched to de-centralized power (co-) generation and experts declared that such a large scale power outage would be impossible in Germany.
- We're All on the Grid Together, Albert-Laszlo Barabasi, NYTimes, 030/8/14
2. Computer 'Worm' Widely Attacks Windows Versions, NYTimes
Excerpts: A computer program aimed at recent versions of the Microsoft Windows operating system rapidly spread through the Internet, infecting tens of thousands of computers. (...)
Even though the possibility of such an attack had been widely anticipated by computer security experts, the worm managed to take advantage of a vulnerability in a common component of Windows(°≠).
On July 16, Microsoft disclosed the vulnerability and offered a protective program, (°≠). On July 31, the Department of Homeland Security followed up with its own warning about the worm's potential for harm.
- Computer 'Worm' Widely Attacks Windows Versions, Kirk Semple, NYTimes, 03/08/12
Excerpts: Researchers (°≠) have created the fastest detailed computer simulations of computer networks ever constructed - simulating networks containing more than 5 million network elements. Packet-level simulations provide a detailed, accurate representation of network behavior (e.g., congestion), but are very time consuming to complete.
"Our team has created a computer simulation that is two to three orders of magnitude faster than simulators commonly used by networking researchers today. This finding offers new capabilities for engineers and scientists to study large-scale computer networks in the laboratory to find solutions to Internet and network problems that were not possible before."
Excerpts: The broadest issue this research raises is what chain-length estimation experiments tell us about natural social processes. They suggest the need to extend our study to a wide range of situations where network chain length actually matters. (°≠) Studies of how people find jobs through social networks show that while chain length is important, information reaches prospects who did not seek it in about one out of three cases (°≠). Though people contract diseases when network distance to the already-infected is short, few searched their networks to achieve this outcome.
- Ignorance, Knowledge, and Outcomes in a Small World, Mark Granovetter, Science 2003 301: 773-774.
Excerpts: We find that successful social search is conducted primarily through intermediate to weak strength ties, does not require highly connected "hubs" to succeed, (°≠). By accounting for the attrition of message chains, we estimate that social searches can reach their targets in a median of five to seven steps, depending on the separation of source and target, although small variations in chain lengths and participation rates generate large differences in target reachability. We conclude that although global social networks are, in principle, searchable, actual success depends sensitively on individual incentives.
- An Experimental Study of Search in Global Social Networks, Peter Sheridan Dodds, Roby Muhamad, and Duncan J. Watts, Science Aug 8 2003: 827-829.
3. 'Spintronics' Could Enable A New Generation Of Electronic Devices, EurekAlert
Excerpts: Theoretical physicists at Stanford and the University of Tokyo says they have discovered the equivalent of a new "Ohm's Law" for spintronics. ''Unlike the Ohm's Law for electronics, the new 'Ohm's Law' that we've discovered says that the spin of the electron can be transported without any loss of energy, or dissipation. Furthermore, this effect occurs at room temperature in materials already widely used in the semiconductor industry, such as gallium arsenide. That's important because it could enable a new generation of computing devices.'' .
- 'Spintronics' Could Enable A New Generation Of Electronic Device, Physicists Say, EurekAlert, 03/08/08
Excerpts: Diamond microchips could handle higher temperatures than today's microprocessors, allowing them to run at speeds that would liquefy ordinary silicon. "If Moore's law is going to be maintained, processors are going to get hotter and hotter,"(°≠).
To grow single-crystal diamond using chemical vapor deposition, you must first divine the exact combination of temperature, gas composition, and pressure - a "sweet spot" that results in the formation of a single crystal. Otherwise, innumerable small diamond crystals will rain down. (°≠) There's only one combination among millions.
- The New Diamond Age, Joshua Davis, Wired, Issue 11.09, 03/09
Excerpts: We report coherent optical control of a biexciton (two electron-hole pairs), confined in a single quantum dot, that shows coherent oscillations similar to the excited-state Rabi flopping in an isolated atom. (°≠) The truth table of the gate shows the features of an all-optical quantum gate with interacting yet distinguishable excitons as qubits. Evaluation of the fidelity yields a value of 0.7 for the gate operation. Such experimental capabilityis essential to a scheme for scalable quantum computation bymeans of the optical control of spin qubits in dots.
- An All-Optical Quantum Gate in a Semiconductor Quantum Dot, Xiaoqin Li, Yanwen Wu, Duncan Steel, D. Gammon, T. H. Stievater, D. S. Katzer, D. Park, C. Piermarocchi, L. J. Sham, Science Aug 8 2003: 809-811
4. Hot Bug Extends Temperature Limit For Life, New Scientist
Excerpts: The researchers then put the bacterium in an autoclave, an oven used to sterilise medical equipment at 121°„C. "Even when we left it there for 10 hours it was still alive," says Lovley. "That was when we were truly amazed." The bug was also found to survive two hours at 130°„C, but did not replicate until returned to a lower temperature. (°≠)
"The biggest excitement from a biochememical point of view is looking at the organism's proteins to see why they can withstand 121°„C when other proteins cannot."
- Hot Bug Extends Temperature Limit For Life, Daphne Chung, New Scientist, 03/08/14
Excerpts: "Human" embryonic stem cells have been harvested from cloned embryos created by fusing human cells with rabbit eggs, claims a soon-to-be published report by Chinese scientists.
The goal of the experiments by Hui Zhen Sheng of Shanghai Second Medical University was to create a new source of embryonic stem cells (ESCs).
These have the ability to transform into any tissue, making them potential sources of replacement cells for the treatment of many diseases.
(°≠)other researchers have had almost no success in their experiments with interspecies cloning techniques
- Human-Rabbit Embryos Intensify Stem Cell Debate, Philip Cohen, New Scientist, 03/08/15
5. Censors of the Genome, Scientific American
Excerpts: Biologists have been surprised to discover that most animal and plant cells contain a built-in system to silence individual genes by shredding the RNA they produce. Biotech companies are already working to exploit it. (...)
Some genes, however, are so subversive that they should never be given freedom of expression. If the genes from mobile genetic elements were to successfully broadcast their RNA messages, they could jump from spot to spot on the DNA, causing cancer or other diseases.
- Censors of the Genome, Nelson C. Lau and David P. Bartel, Scientific American, 03/08
6. Shape Shifters Tread a Daunting Path Toward Reality, Science
Excerpt: New designs of robots built from cell-like modules are learning to walk, slither, roll, flow, and reinvent themselves on the fly
From Star Trek to Star Wars to Terminator, science-fiction movies and TV series teem with morphing robots. If that vision is indeed a sneak preview of things to come, then the future of robotics is lying face down on a table in Mark Yim's laboratory at the Palo Alto Research Center (PARC) in California. Or rather, was lying face down, because now it's trying to stand up.
- Shape Shifters Tread a Daunting Path Toward Reality, Dana Mackenzie, Science Aug 8 2003: 754-756
Excerpts: If you want a lattice robot to morph from, say, a wheel to a centipede, your best bet now is a sort of blind flailing around through configuration space that takes you from wheel-like shapes to centipede-like shapes. But Ghrist and Abrams have devised a path-shortening algorithm that shrinks the random stagger down to the shortest possible path. Their idea exploits the possibility of moving cubes simultaneously whenever they don't interfere with each other. It also uses a deep theorem by French topologist Mikhael Gromov (°≠).
- Topologists and Roboticists Explore an 'Inchoate World', Dana Mackenzie, Science Aug 8 2003: 756
7. Endogenous Insecurity And Economic Development, J. Dev. Econ.
Abstract: We explore the implications of endogenous credit market imperfections for the endogenous relationship between investment insecurity and the process of economic development. In the initial stages of development, the fraction of agents engaged in nonproductive diversionary activities (e.g. rent-seeking) grows as the opportunities to gain from diversionary activities expand. (°≠) diversion falls as capital market imperfections are overcome and productive activities become more secure and more profitable. We detail the forces that determine whether the insecurity generated by an economy's early development will choke off the growth process. We also compare the cost-effectiveness of alternative policies designed to prevent diversion.
8. Harvesting Poverty: Inching Toward Trade Fairness, NYTimes
Excerpts: Poor and developing nations have long - and rightly - complained that while the richest countries want open markets for their manufactured goods, they rig the game when it comes to agricultural products. Now it appears that the United States and Europe are beginning to get the message. Their trade negotiators have agreed to try to reduce their farm subsidies and other barriers to agricultural imports. The vague agreement, announced on Wednesday, falls short of what is needed and raises as many questions as it answers
- Harvesting Poverty: Inching Toward Trade Fairness, NYTimes, 03/08/15
Abstract: An important issue in public policy debates is the effect of international migration on welfare in source and host countries. We address this issue by constructing a general equilibrium model of a two-class source or host country. Each country produces many traded and non-traded goods, uses income taxes and distributes the tax receipts equally to all individuals. The analysis examines the effects of permanent migration on class, and national welfare. We show, among other things, that marginal immigration hurts people already in the country regardless of whether or not non-traded goods exist.
- International Migration, Income Taxes And Transfers: A Welfare Analysis, M. S. Michael, J. Dev. Econ., Vol. 72, Issue 1, Oct. 2003, pp:401-411, doi:10.1016/S0304-3878(03)00084-1
- Contributed by Pritha Das
Excerpt: This paper furnishes robust evidence that the GATT/WTO has had a powerful and positive impact on trade. The impact has, however, been uneven. GATT/WTO membership for industrial countries has been associated with a large increase in trade estimated at about 40 percent of world trade. The same has not been true for developing country members, although those that joined after the Uruguay Round have benefited from increased trade.
Similarly, there has been an asymmetric impact between sectors, with WTO membership associated with substantially greater trade in sectors where barriers are low.
- The WTO Promotes Trade, Strongly But Unevenly, Shang-Jin Wei, Brookings Views, 03/08
Excerpts: In an effort to breathe life into global trade negotiations, the United States and the European Union said today that they had agreed on a way to reduce the subsidies and import duties used to protect their farmers. (°≠)
Developing countries are pushing hardest for global cuts in farm subsidies and import tariffs that make their products less competitive in other markets. Developed countries, likewise, are looking to gain easier access to developing markets and especially China, the W.T.O.'s newest member.
- Deal Reached on Subsidies for Farmers, Paul Meller, David Barboza, NYTimes, 03/08/14
9. Some Results On Ruin Probabilities In A Two-Dimensional Risk Model, Insurance: Math. & Econ.
Abstract: Ruin theory under multi-dimensional risk models is very complex. Even in the two-dimensional case, the problem is challenging. In this paper, we consider a bivariate risk model. Three different types of ruin probabilities are defined. Numerical examples and simulation experiments are given to illustrate the tightness of the bounds. A partial integral®Cdifferential equation satisfied by the two-dimensional ruin probabilities is derived. Although special cases and examples in this paper provide some exciting results, the problem of ruin probability in a multi-dimensional risk model is still far from solved.
- Some Results On Ruin Probabilities In A Two-Dimensional Risk Model, W. S. Chan, H. Yang & L. Zhang, Insurance: Math. & Econ., Vol. 32, Issue 3, pp:345-358, 2003/07/21, doi:10.1016/S0167-6687(03)00115-X
- Contributed by Pritha Das
10. Atmospheric Science: African Dust In Florida Clouds, Nature
Excerpts: Intercontinental transport of dust has several implications, some of which have been recognized only recently. Dust scatters and absorbs sunlight, as well as infrared light radiated by the Earth, which alters the radiation budget and is a major factor in studies of climate and climate change. It is difficult to regulate air-pollution standards when they are violated by dust storms occurring halfway around the world. In different contexts, wind-blown dust is a significant source of minerals for oceanic plankton,(°≠).
- Atmospheric Science: African Dust In Florida Clouds, Owen B. Toon, Nature 424, 623 - 624 (07 August 2003); doi:10.1038/424623a
11. Cooler Butterflies Lay Larger Eggs: Developmental Plasticity Versus Acclimation, Alphagalileo & Proc. B.
Abstract: Although appealing, the beneficial acclimation hypothesis (plastic changes enhance fitness in the environment in which they were induced) is currently under debate. It is argued that many studies not supporting it fact tested the significance of developmental plasticity, but not that of acclimation in the adult stage. Our study, investigating temperature-mediated plasticity in butterfly egg size, shows that developmental plasticity and acclimation can result in very similar patterns. Consequently, we argue that the crucial question is not at which stage a given plasticity is induced, but whether plastic responses to environmental change are adaptive.
- Cooler Butterflies Lay Larger Eggs: Developmental Plasticity Versus Acclimation, K. Fischer, E. Eenhoorn, A. N. M. Bot, P. M. Brakefield & B. J. Zwaan, Alphagalileo & Proc. B., 2003/08/11
- Contributed by Atin Das
Excerpts: A new study (°≠) revealed that non-native plants typically received equal or greater levels of attack than native plants. Thus, invasive plants may be more likely to establish only if they lack close relatives in the new habitat. Ever since Charles Darwin proposed the ''naturalization hypothesis'', scientists have attempted to understand the factors that allow non-native organisms to establish and flourish. Non-native plants and animals often become invasive and cause major economic and aesthetic losses. Thus, concordant with Darwin''s idea, invasive plants may be more likely to establish only if they lack close relatives in the new habitat.
Abstract: In order to further characterize the function of coloration in plants as defense against herbivory, two types of thorn mimicry are described: (1) A unique type of weapon (thorn) automimicry (within the same individual) that was previously known only in animals, and (2) mimicry of aposematic colorful thorns, by colorful elongated and pointed plant organs (buds, leaves and fruit) that, despite their appearance, are not sharp. Some thorny plants (°≠) a palm species have thorn-like imprints or colorations on their leaves, constituting thorn automimicry by giving the impression of more extensive thorns. I propose that both types of mimicry serve as anti-herbivore mechanisms.
- Weapon (Thorn) Automimicry And Mimicry Of Aposematic Colorful Thorns In Plants, S. L. Yadun, J. Theor. Biol., Vol. 224, Issue 2, 2003/09/21, pp:183-188, doi:10.1016/S0022-5193(03)00156-5
- Contributed by Pritha Das
12. Bottlenose Dolphins Perceive Object Features Through Echolocation, Nature
Excerpts: In the echoic-visual condition, samples were presented underwater behind a thin black polyethylene screen that was visually opaque but echoically transparent; the choice alternatives were presented in air, thus making them visually, but not echoically, available.(°≠)
Even when the dolphin was rewarded for choosing an arbitrary stimulus, it still chose the identical object. Therefore, reinforcement cannot be the mechanism that allows the dolphin to recognize the correspondence between the different sensory modalities. (°≠) Organisms can perceive object characteristics directly.
- Bottlenose Dolphins Perceive Object Features Through Echolocation, Heidi E. Harley, Erika A. Putman & Herbert L. Roitblat, Nature 424, 667 - 669 (07 August 2003); doi:10.1038/nature01846
Excerpts: The neural representations associated with learned auditory behaviours, such as recognizing individuals based on their vocalizations, are not well described. Higher vertebrates learn to recognize complex conspecific vocalizations that comprise sequences of easily identified, naturally occurring auditory objects, which should facilitate the analysis of higher auditory pathways. Here we describe the first example of neurons selective for learned conspecific vocalizations in adult animals-in starlings that have been trained operantly to recognize conspecific songs. The neuronal population is found in a non-primary forebrain auditory region, exhibits increased responses to the set of learned songs compared with novel songs, and shows differential responses to categories of learned songs based on recognition training contingencies. Within the population, many cells respond highly selectively to a subset of specific motifs (acoustic objects) present only in the learned songs. Such neuronal selectivity may contribute to song-recognition behaviour, which in starlings is sensitive to motif identity. In this system, both top-down and bottom-up processes may modify the tuning properties of neurons during recognition learning, giving rise to plastic representations of behaviourally meaningful auditory objects.
- Neuronal Populations And Single Cells Representing Learned Auditory Objects, Timothy Q. Gentner And Daniel Margoliash, Nature 424, 669 - 674 (07 August 2003); doi:10.1038/nature01731
Excerpts: Some mice are cleverer than others, say US neuroscientists. Their rodent equivalent of an IQ test might fuel the controversial pursuit for genes linked to human intelligence.
Scientists have long used a factor called general intelligence or 'g' to rate people's brainpower. (°≠)
Mice have a version of 'g', according to a team led by Louis Matzel of Rutgers University in Piscataway, New Jersey. Animals that come top in one learning test often score better on others, they found: a maze champion might be a sniffing sensation too.
- Mouse Intelligence Measured, Helen Pearson, Nature, 03/08/01
13. Depression Drugs' Powers May Rest on New Neurons, Science
Excerpt: Blocking neurogenesis in adult mice renders antidepressants ineffective, lending support to a theory that a dearth of newborn neurons contributes to depression
People who recover from depression sometimes speak of feeling reborn. Tantalizing evidence suggests that this renaissance isn't merely metaphoric: In the brain, newborn neurons may help ease depression.
Several seemingly disconnected observations lie behind the idea that neurogenesis and depression are linked. Stress, which suppresses neurogenesis, can also trigger bouts of depression.
Certain brain regions in chronically depressed patients tend to be smaller (°≠).
- Depression Drugs' Powers May Rest on New Neurons, Gretchen Vogel, Science Aug 8 2003: 757
14. Neural Correlates Of Implied Motion, Nature
Excerpts: (°≠) STS [superior temporal sulcus, Ed.] cells respond to dynamic Glass patterns, which contain no coherent motion but suggest a path of motion. Second, we show that when motion signals conflict with form signals suggesting a different path of motion, both humans and monkeys perceive motion in a compromised direction. (°≠) We conclude that cells in the prototypical motion areas in the dorsal visual cortex process form that implies motion. Estimating motion by combining motion cues with form cues may be a strategy to deal with the complexities of motion perception in our natural environment.
- Neural Correlates Of Implied Motion, Bart Krekelberg, Sabine Dannenberg, Klaus-Peter Hoffmann, Frank Bremmer & John Ross, doi:10.1038/nature01852, Nature 424, 674 - 677 (07 August 2003); doi:10.1038/nature01852
15. Neurobiology: A Thorny Issue, Nature
Excerpts: A protein has been identified that makes spines grow on nerve cells. Unexpectedly, it also turns out to be part of an ion channel that is responsible for transmitting signals between neurons. (°≠)
These spines are more than just structural protuberances: it seems that spine growth can be induced by stimulating neurons, indicating that changes in spine density may reflect changes in the synaptic activity - and hence the computational power - of individual neurons.
(°≠) abnormalities in spine density or shape are associated with human cognitive disorders, such as Down's syndrome (°≠)
- Neurobiology: A Thorny Issue, Peter H. Seeburg, Pavel Osten, Nature 424, 627 - 628 (07 August 2003); doi:10.1038/424627a
Excerpts: Synaptic transmission from excitatory nerve cells in the mammalian brain is largely mediated by AMPA (°≠)-type glutamate receptors located at the surface of dendritic spines. (°≠) Moreover, long-term potentiation is associated with the formation of dendritic spines as well as synaptic delivery of AMPA receptors. The molecular mechanisms that coordinate AMPA receptor delivery and spine morphogenesis are unknown. Here we show that overexpression of the glutamate receptor (°≠) increases spine size and density in hippocampal neurons, and more remarkably, induces spine formation in GABA-releasing interneurons that normally lack spines.
- Induction Of Dendritic Spines By An Extracellular Domain Of AMPA Receptor Subunit GluR2, Maria Passafaro, Terunaga Nakagawa, Carlo Sala & Morgan Sheng, doi:10.1038/nature01781
16. Emergence of Scale-free Properties in Hebbian Networks, arXiv
Abstract: The fundamental `plasticity' of the nervous system (i.e high adaptability at different structural levels) is primarily based on Hebbian learning mechanisms that modify the synaptic connections. The modifications rely on neural activity and assign a special dynamic behavior to the neural networks. Another striking feature of the nervous system is that spike based information transmission, which is supposed to be robust against noise, is noisy in itself: the variance of the spiking of the individual neurons is surprisingly large which may deteriorate the adequate functioning of the Hebbian mechanisms. In this paper we focus on networks in which Hebbian-like adaptation is induced only by external random noise and study spike-timing dependent synaptic plasticity. We show that such `HebbNets' are able to develop a broad range of network structures, including scale-free small-world networks. The development of such network structures may provide an explanation of the role of noise and its interplay with Hebbian plasticity. We also argue that this model can be seen as a unification of the famous Watts-Strogatz and preferential attachment models of small-world nets.
- Emergence of Scale-free Properties in Hebbian Networks, Gabor Szirtes, Zsolt Palotai, Andras Lorincz, 2003-08-11, DOI: nlin.AO/0308013, arXiv
- Contributed by Carlos Gershenson
17. Power From Blood Could Lead To 'Human Batteries', KurzweilAI.net
Excerpts: Researchers in Japan are developing a method of drawing power from blood glucose, mimicking the way the body generates energy from food. Theoretically, it could allow a person to pump out 100 watts, ignoring body needs. The "bio-nano" generator could be used to run devices embedded in the body or...
- Power From Blood Could Lead To 'Human Batteries', , KurzweilAI.net, 03/08/04
Excerpts: The "vasculoid," conceived by Chris Phoenix and Robert Freitas, is a theoretical nanomachine that would replace the human blood supply. It would exclude parasites, bacteria, viruses, and metastasizing cancer cells from the blood flow; eradicate most vascular diseases; result in faster oxygen...
- Roboblood, KurzweilAI.net, 03/08/04 August 8, 2003
18. Pattern Recognition in a Bucket, ECAL 2003
Abstract: This paper demonstrates that the waves produced on the surface of water can be used as the medium for a "Liquid State Machine" that pre-processes inputs so allowing a simple perceptron to solve the XOR problem and undertake speech recognition. Interference between waves allows non-linear parallel computation upon simultaneous sensory inputs. Temporal patterns of stimulation are converted to spatial patterns of water waves upon which a linear discrimination can be made. Whereas Wolfgang Maass' "Liquid State Machine" requires fine tuning of the spiking neural network parameters, water has inherent self-organising properties such as strong local interactions, time-dependent spread of activation to distant areas, onherent stability to a wide variety of inputs, and high complexity. Water achieves this "for free", and does so without the time-consuming computation required by realistic neural models. An analogy is made between water molecules and neurons in a recurrent neural network.
19. Complex Challenges: Global Terrorist Networks
Excerpts: The story of the 'capture and arrest' of alleged arms dealer Hemant Lakhani is getting weaker by the hour, while the Indian community in Britain is shocked that one of them had been linked to a terror plot. (°≠)
In sum, Lakhani's 'terrorist clients' were FBI agents, his "suppliers" Russian intelligence officers and the surface-to-air missile he smuggled into the US was a dummy. (°≠)
Questions are being raised about the entire episode, with suggestions that the accused was entrapped and that American officials merely stopped what they themselves had initiated and choreographed.
- Lakhani's Terror Links May Be In US Eyes Only, Prasun Sonwalkar, Economic Times (India), 03/08/16
Excerpts: Until the end of the operation not a single real terrorist was involved in that business. Everything started a year ago when FBI agents learned that the British citizen -now under arrest- boasted that he could provide surface to air missiles. Two FBI agents then made a generous offer. (...) In the following months agents of the Russian FSB provided him with a non-functioning rocket. (...) It is questionable if the arms dealer would have been able to obtain this dangerous weapon without the active help of the FSB.
- A Terror-Plot Without Terrorists, Matthias Gebauer, Der Spiegel, 03/08/13 (in German)
Abstract: To evaluate existing and alternative proposals for emergency response to a deliberate smallpox attack, we embed the key operational features of such interventions into a smallpox disease transmission model. We use probabilistic reasoning within an otherwise deterministic epidemic framework to model the `race to trace', i.e., attempting to trace (via the infector) and vaccinate an infected person while (s)he is still vaccine-sensitive. Our model explicitly incorporates a tracing/vaccination queue, and hence can be used as a capacity planning tool. An approximate analysis of this large (16 ODE) system yields closed-form estimates for the total number of deaths and the maximum queue length.
- Analyzing Bioterror Response Logistics: The Case Of Smallpox, E. H. Kaplan, D. L. Craft & L. M. Wein, Math. Biosc., Vol. 185, Issue 1, pp:33-72, Sep. 2003, doi:10.1016/S0025-5564(03)00090-7
- Contributed by Pritha Das
Excerpts: Yet many scientists and economists see the project as a clever scheme to harness the expertise of hundreds or thousands of people, essentially creating a social-science supercomputer out of flesh rather than silicon. And many fear that the worthwhile ideas behind "information markets" such as the Pentagon project will be lost in the political fallout. (°≠)
Yet, theoretically, information markets tend to be self-correcting; knowledgeable people make money and increase their standing in the market, while clueless people lose their money and cease to have any influence.
- 'Terrorism Futures' Could Have a Future, Experts Say, Charles Seife, Science Aug 8 2003: 749.
20. Links & Snippets
20.1 Other Publications
- Science News, Vol. 164, No. 6, 03/08/09 (available in Audible Format)
- Virus Shield: Ebola Vaccine Works Fast In Monkey Test, Tests on monkeys show that an experimental vaccine can build immunity against Ebola virus within a month, suggesting the vaccine might help contain outbreaks of the deadly pathogen.
- A Human Migration Fueled By Dung?, Sid Perkins, When people made their way from Asia to the Americas, the path they took may have been covered in dung.
- New World Newcomers: Men's Dna Supports Recent Settlement Of The Americas, Ben Harder, New data on genetic differences among the Y chromosomes of Asian and Native American men support the notion that people first reached the Americas less than 20,000 years ago.
- Three Species No Moa? Fossil DNA Analysis Yields Surprise, Analyses of genetic material from the fossils of large flightless birds called moas suggest that three types of the extinct birds may not be separate species after all.
- Shark Serengeti: Ocean Predators Have Diversity Hot Spots, The first search for oceanic spots of exceptional diversity in predators has turned up marine