Dec. 01, 2003
Hydrocarbons And The Evolution Of Human Culture, Nature 
Excerpt: Most of the progress in human culture has required the exploitation of energy resources. About 100 years ago, the major source of energy shifted from recent solar to fossil hydrocarbons, including liquid and gaseous petroleum. Technology has generally led to a greater use of hydrocarbon fuels for most human activities, making civilization vulnerable to decreases in supply. At this time our knowledge is not sufficient for us to choose between the different estimates of, for example, resources of conventional oil.
The Long-Term Carbon Cycle, Fossil Fuels And Atmospheric Composition, Nature
Excerpts: The long-term carbon cycle operates over millions of years and involves the exchange of carbon between rocks and the Earth's surface. There are many complex feedback pathways between carbon burial, nutrient cycling, atmospheric carbon dioxide and oxygen, and climate. New calculations of carbon fluxes during the Phanerozoic eon (the past 550 million years) illustrate how the long-term carbon cycle has affected the burial of organic matter and fossil-fuel formation, as well as the evolution of atmospheric composition.
(...) take place over timescales ranging from hours to millions of years.
Two Measures Of Progress In Adapting To Climate Change, Global Env. Change
Abstract: Adaptation will play a key role in determining the economic and social costs of climate change. One important measure of adaptation is reductions in deaths caused by climate events. This paper uses two new data sets to test the hypothesis that, in recent years, climate events cause less deaths than in the past. Using data on deaths caused by natural disasters and data on skin cancer death rates in warmer and cooler US states, this paper reports evidence in favor of the adaptation progress hypothesis.
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Excerpts: Past studies have suggested a statistical connection between explosive volcanic eruptions and subsequent El Niņo climate events. (...) Here we present support for a response of the El Niņo/Southern Oscillation (ENSO) phenomenon to forcing from explosive volcanism (...).
The results imply roughly a doubling of the probability of an El Niņo event occurring in the winter following a volcanic eruption. Our empirical findings shed light on how the tropical Pacific ocean-atmosphere system may respond to exogenous (both natural and anthropogenic) radiative forcing.
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Excerpts: The beauty of jagged, rocky coastlines will prevail, however hard the sea pounds them. The classic coastal profile is a balance between the sea's eroding power and the ability of the coastline to damp it out, say researchers in France and Italy.
Although a coast continues to crumble and break up under the relentless assault of the waves, it soon adopts a pitted, fractal form that modifies the force that erodes it. "Whatever its initial shape, a rocky shore will end up fractal," the researchers conclude.
Tropical Soils and Food Security: The Next 50 Years, Science
Excerpts: An appreciation of the dynamism of the links between soil resources and society provides a platform for examining food security over the next 50 years. Interventions to reverse declining trends in food security must recognize the variable resilience and sensitivity of major tropical soil types. In most agro-ecosystems, declining crop yield is exponentially related to loss of soil quality. (...), investments to reverse degradation are primarily driven by private benefit, socially or financially. "Tragedy of the commons" scenarios can be averted by pragmatic local solutions that help farmers to help themselves.
The Future for Fisheries, Science
Excerpts: Formal analyses of long-term global marine fisheries prospects have yet to be performed, because fisheries research focuses on local, species-specific management issues. Extrapolation of present trends implies expansion of bottom fisheries into deeper waters, serious impact on biodiversity, and declining global catches, the last possibly aggravated by fuel cost increases. Examination of four scenarios, covering various societal development choices, suggests that the negative trends now besetting fisheries can be turned around, and their supporting ecosystems rebuilt, at least partly.
- Source: The Future for Fisheries, Daniel Pauly, Jackie Alder, Elena Bennett, Villy Christensen, Peter Tyedmers, Reg Watson, Science Nov 21 2003: 1359-1361.
The Origins of Genome Complexity, Science
Excerpts: Complete genomic sequences from diverse phylogenetic lineages reveal notable increases in genome complexity from prokaryotes to multicellular eukaryotes. (...) emerged passively in response to the long-term population-size reductions that accompanied increases in organism size. According to this model, much of the restructuring of eukaryotic genomes was initiated by nonadaptive processes, and this in turn provided novel substrates for the secondary evolution of phenotypic complexity by natural selection. The enormous long-term effective population sizes of prokaryotes may impose a substantial barrier to the evolution of complex genomes and morphologies.
Learning to Speak the Language of Proteins, Science
Excerpts: Understanding the folding of proteins can be likened to learning to speak a new language. Learning a language can be a long and difficult process. (...) Finally, after a great deal of practice, the learner begins to understand the actual syntax of the language, and the process is almost complete. Applying this analogy to the report on page 1364 of this issue, we can say that Kuhlman et al. (1) have spoken a new sentence in the complex language of protein folding and have been understood perfectly.
Public Projects Gear Up to Chart the Protein Landscape, Science
Excerpts: With the human gene sequence now in hand, researchers have moved on to a new goal: identifying all the body's proteins. The task is massive. Not only does each of the body's 252 cell types harbor its own complement of proteins, but their expression patterns also vary with age, nutrition, health, and disease . (...)
Once researchers have collected snapshots of the ever-changing proteomes of different tissues and cells, they hope to assemble them into a kind of full-length movie showing the ebb and flow of proteins in the body.
Proteomics: A Sharper Focus, Science
Excerpts: The large-scale proteomic surveys coordinated by the Human Proteome Organization (HUPO) have a long way to go to produce their promised medical benefits ( see main text). But more-focused proteomic projects may have a more immediate impact. Researchers around the globe are hard at work using proteomic technologies to identify the proteins that make up the mitochondria, the cell's energy powerhouse, and other subcellular structures. (...) how proteomic tools can lead to crucial new insights into cell biology as well as potential medical benefits.
Rebuilding The Heart: Marrow Cells Boost Cardiac Recovery, Science News
Excerpts: Experimental therapy that infuses a person's bone marrow cells into his or her damaged heart tissue is showing early success, scientists report. First tried in patients 2 years ago, the technique is designed to stimulate the growth of new, healthy heart cells. The treatment could help people who've had recent heart attacks, as well as those who've been battling heart disease for years (...)
(...)people who have marrow cells inserted into their hearts within days of a heart attack exhibit improvement.
British Firm Plans Human Stem Cell Trial-Magazine, Reuters
Excerpts: A British company is planning human trials of a new technique which it says can transform white blood cells into stem cells that can be used to treat leukemia and a range of other diseases. London-based TriStem says the method it has developed eliminates the need for embryos and fetuses, rich sources of the stem cells that can develop into any cell type. The use of early embryos has been a major stumbling block in the use of stem cells. "TriStem has been claiming for years that it can take a half liter of anyone's blood, extract the white blood cells and make them revert to a stem cell-like state," New Scientist magazine said on Wednesday.
Marijuana-Like Compounds Linked to Embryo Growth, NPR Audio
Excerpts: Researchers discover that marijuana-like compounds produced by the body can help regulate the growth of mouse embryos. Scientists believe the findings could have implications for fertility research in humans. NPR's Joe Palca reports.
Complexity in the Immune System, arXiv
Abstract: The immune system is a real-time example of an evolving system that navigates the essentially infinite complexity of protein sequence space. How this system responds to disease and vaccination is discussed. Of particular focus is the case when vaccination leads to increased susceptibility to disease, a phenomenon termed original antigenic sin. A physical theory of protein evolution to explain limitations in the immune system response to vaccination and disease is discussed, and original antigenic sin is explained as stemming from localization of the immune system response in antibody sequence space. This localization is a result of the roughness in sequence space of the evolved antibody affinity constant for antigen and is observed for diseases with high year-to-year mutation rates, such as influenza.
Velocity and Hierarchical Spread of Epidemic Outbreaks in Complex Networks, arXiv
Abstract: We study the effect of the connectivity pattern of complex networks in the propagation dynamics of epidemics. The growth time scale of outbreaks is inversely proportional to the network degree fluctuations, signaling that epidemics spread almost instantaneously in networks with scale-free degree distributions. This feature is associated to an epidemic propagation that follows a precise hierarchical dynamics. Once reached the highly connected hubs, the infection pervades the network in a progressive cascade across smaller degree classes. The present results are relevant for the development of adaptive containment strategies.
How Fielders Arrive In Time To Catch The Ball, Nature
Excerpts: Here we show how fielders use such tracking signals to arrive at the right place in time to catch a ball - they run so that their angle of gaze elevation to the ball increases at a decreasing rate while their horizontal gaze angle to the ball increases at a constant rate (unless the distance to be run is small). Allowing the horizontal angle to increase minimizes the acceleration that the fielder must achieve to reach the interception point at the same time as the ball.
Giving Eyesight To The Blind Raises Questions About How People See, Science News
Excerpts: He has difficulty identifying everyday items, distinguishing male from female faces, and recognizing emotional expressions on unfamiliar faces. May keeps track of people's faces by noting hair length, eyebrow shape, and other individual features.
May does track his own and others' movements with precision. He also distinguishes shaded areas from illuminated surfaces. With these capabilities, he's made a transition from being an expert blind skier, who depended on verbal directions from a sighted guide, to being a competent sighted skier.
Complexities Of A Simple System: New Lessons, Old Challenges For The Gill Withdrawal, Brain Res. Rev.
Abstract: The gill withdrawal reflex of Aplysia is generally depicted as a simple behaviour mediated by a simple neural circuit in a simple organism. Such a view has permitted a clear focus upon synapses between relatively small numbers of identified neurones, (...) is anything but simple. First, the behaviour itself is complex (...). While daunting, the complexity of the total circuitry mediating the gill withdrawal reflex may provide yet another important lesson: even in simple systems, memory may not be localized to specific loci, but rather may be an emergent property of physiological mechanisms distributed throughout the entire circuitry.
Why Ants Do But Honeybees Do Not Construct Satellite Nests, J. Bioecon.
Abstract: Ants and honeybees are both social insects that share many characteristics in common. Ants can and do construct main nests with satellite nests, whereas bees construct only a main nest with no satellite nests. In this paper we explain the difference between the socio-economic organization of ants and bees: ants can identify nest-mates from satellite nests because ants leave odor trails connecting main nests to satellite nests so that fellow nest-mate from satellite nests smell the same. Bees, on the other hand, cannot leave odor trails in the air, and hence are unable to identify bees from another nest (...).
Chicks Unite To Increase Parent-Pestering, Natue Science update
Excerpts: Children accompanying their parents on Christmas shopping trips: take a tip from black-headed gull chicks, and team up with your siblings to increase pester power.
Gull nestlings put aside their differences and coordinate their begging to extract the maximum amount of regurgitated food from mum and dad, French researchers have discovered.
It flies in the face of conventional wisdom - children should fight each other for the biggest share of parental care. "Competition should increase with the number of chicks, but that's not what we found,"(...)
Essay: Monkeys and Dolphins, NPR Audio
Excerpts: NPR's Scott Simon reflects on a study released this week that has found that monkeys and dolphins are capable of making cognitive choices.
The Physics of Fish, NPR Audio
Summary: Fish have developed a neat trick that helps them swim upstream. When water flows past objects in a stream, it develops a string of small whirlpools, or "vortices." A researcher simulated this environment in a tank outfitted with a high-speed camera. They found that fish slalomed in between the vortices and used the energy of each one to help propel them forward -- much the same way that a boater uses a sail to tack back and forth in the wind. NPR's Christopher Joyce reports.
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Excerpts: Each hallucinogen altered the same mystery brain protein, DARPP-32, (...)Animals developed schizophrenic symptoms (...). Mice lacking DARPP-32 were immune to the drugs' psychotic effects, (...).
Current therapies damp down one neurotransmitter called dopamine. Delusions subside but attention and memory problems often persist, and serious adverse effects are common.
Drugs that target DARPP-32 would affect several neurotransmitters, says dopamine expert Ariel Deutch of Vanderbilt University in Nashville, Tennessee. This might make them more effective with fewer side-effects, (...).
Compartments Revealed In Food-Web Structure, Nature
Excerpts: Similarity between human social networks and food webs has recently been noted (...). In the social sciences, cohesive subgroups in human communities have been an important concept since the 1950s, when it was proposed that social systems were more efficient and durable when composed of subgroups in which interactions were concentrated. (....) This is also the case for food-web compartments in ecology, wherein methods for identifying compartments have often emphasized the similarity of prey and predators between taxa, which results in little direct interaction or carbon exchange within compartments.
- Source: Compartments Revealed In Food-Web Structure, Ann E. Krause,, Kenneth A. Frank,, Doran M. Mason,, Robert E. Ulanowicz,, William W. Taylor, DOI: 10.1038/nature02115, Nature 426, 282 - 285, 20 November 2003
Plant Development: Leaves By Number, Nature
Excerpts: Auxin is a growth stimulator that is propelled through plant tissues (...). Existing leaf buds act as sinks, preventing auxin from continuing its progress directly above them. The maximum auxin concentration, and so the site of new leaf formation, is thus as far away as possible from already-formed leaves.
(...) mechanism in which the position of leaves is determined neither by a physical property of the stem, nor by an inhibitory field produced by growing leaves. Instead, the gaps between leaves, (...), mark out the position of each new leaf.
Signal Transduction: An Eye On Organ Development, Nature
Excerpts: Studies in flies and mice have revealed a surprising way in which cells regulate gene activity, with consequences for our understanding of organ formation during development. (...)
Among the most remarkable discoveries of the past decade has been the identification of single genes that can induce the formation of entire organs or tissues. In fruitflies (Drosophila melanogaster), for example, misexpression of a single gene called Eyeless, one of several 'retinal-determination' genes that encode transcription factor, is enough to evoke eyes where eyes shouldn't be ('ectopic' eyes).
Drying-Mediated Self-Assembly Of Nanoparticles, Nature
Excerpts: Systems far from equilibrium can exhibit complex transitory structures, even when equilibrium fluctuations are mundane. A dramatic example of this phenomenon has recently been demonstrated for thin-film solutions of passivated nanocrystals during the irreversible evaporation of the solve. The relatively weak attractions between nanocrystals, which are efficiently screened in solution, become manifest as the solvent evaporates, initiating assembly of intricate, slowly evolving structures. Although certain aspects of this aggregation process can be explained using thermodynamic arguments alone, it is in principle a non-equilibrium process.
DNA-Templated Carbon Nanotube Field-Effect Transistor, Science
Excerpts: The combination of their electronic properties and dimensions makes carbon nanotubes ideal building blocks for molecular electronics. However, the advancement of carbon nanotube-based electronics requires assembly strategies that allow their precise localization and interconnection. Using a scheme based on recognition between molecular building blocks, we report the realization of a self-assembled carbon nanotube field-effect transistor operating at room temperature. A DNA scaffold molecule provides the address for precise localization of a semiconducting single-wall carbon nanotube as well as the template for the extended metallic wires contacting it.
Nanodevices Make Fresh Strides Toward Reality, Science
Excerpts: On page 1380, biophysicist Erez Braun and colleagues at the Technion-Israel Institute of Technology in Haifa report using a combination of proteins and DNA to direct the synthesis of a carbon nanotube-based transistor, a success that could pave the way for complex circuitry to essentially build itself. Meanwhile, in another paper on page 1377, a team led by Harvard University chemist Charles Lieber reports creating a scheme for feeding electrical impulses to specific locations in a nanocircuit, an essential step for carrying out complex computation.
Historic Maths Problem 'Cracked', BBC News Online
Excerpts: A 22-year-old student at Stockholm University, Elin Oxenhielm, may have solved part of one of mathematics' greatest unsolved problems.
Called Hilbert's problem 16, it has confounded workers for over a century. (...)
Her research into so-called planar polynomial vector fields may have practical applications for computer simulations in science and economics.
(...) special version of the second part of the problem, called the "boundary cycles for polynomial differential equations". (...)
It may improve the way scientists use computers to simulate such diverse phenomena as global warming and economies.
Time Use, Work And Overlapping Activities: Evidence From Australia, Cambridge J. Econ.
Abstract: The overlapping of activities is an important dimension of time use that has previously received little attention in economic analysis. Most time-use studies have looked only at primary activities, ignoring the fact that individuals often perform two or more activities simultaneously. This seriously underestimates the time spent on several economic activities such as childcare and housework which are also performed as secondary activities. (...) this paper examines the incidence and determinants of overlapping activities (...) shows that inclusion of overlapping activities in time-use measurements provides a better estimation of the economic contribution of individuals, especially in non-market production.
Opinion Formation in Networked Societies with Strong Leaders, arXiv
Abstract: Recent studies show that many types of human social activities, from scientific collaborations to sexual contacts, can be understood in terms of complex network of interactions. Such networking paradigm allows to model many aspects of social behaviour with relatively simple computer models. The present work investigates the influence of single leaders on opinion formation within simulations of agent based artificial networked societies. Several types of network systems (among them random networks, highly clustered, small world and scale-free) are studied. The strength of the social influence of individuals is assumed to be dictated by distance from an agent to another, as well as individual strengths of the agents. We study the effect of different topologies on the conditions of general acceptance of leader's opinion by the society.
U.S. Is Worried Foe Is Tracking Targets in Iraq, NYTimes
Excerpts: Anti-American forces in Iraq may be using simple but effective means to monitor activities and coordinate attacks against the U.S. military and its allies. (...)
American officials say operatives loyal to the ousted Hussein government do not require high-technology eavesdropping devices to gather substantial amounts of information on the activities of American officials. "Given the size of our footprint, you can't overestimate the amount of information you can gather just standing on a street corner and watching," one official said.
Licenses for Illegal Immigrants, NYTimes
Excerpts: (...) controversy over whether an illegal immigrant should have a driver's license. Obviously on one level it makes no sense for the government to be issuing documents - documents that are frequently used as identification cards - to people who should in theory be deported. (...) estimated seven million people in the country illegally. Our law enforcement officials are not making any serious effort to find them, and our political leaders are not making any serious effort to come up with a system that would expand their ability to work here legally.
Complex Challenges: Global Terrorist Networks
Facing The Nuclear Danger, Nature
Excerpts: The war on terrorism threatens to overshadow the greatest weapons-proliferation challenge of all - the safe management of nuclear materials in the former Soviet Union.
Saddam Hussein, Osama Bin Laden and Kim Jong-Il are each well-known for their possible ties to weapons of mass destruction, but has anyone heard of Alexander Tyulyakov? Tyulyakov was deputy director of Atomflot - the state-owned company overseeing Russia's fleet of nuclear icebreakers. In August, he was arrested (...) and charged with trying to sell more than a kilogram of uranium and radium to nuclear smugglers.
Theft of Cobalt in Iraq Prompts Security Inquiry, NYTimes
Excerpts: A seeming lapse in surveillance by American forces has led to the looting of dangerously radioactive capsules from Saddam Hussein's main battlefield testing site in the desert outside Baghdad and the identification of at least one 30-year-old Iraqi villager, and possibly a village boy, as suffering from radiation sickness.
The two capsules, taken from a site once used by Mr. Hussein's government to test the effects of radiation on animals and perhaps humans, have since been recovered after an American sweep through the area. 
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Complexity, London, UK, 03/10/08-10
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tufts.edu, DOI: 10.1016/S0959-3780(03)00052-9, Global Environmental Change, 2003/11/21