22,814 research outputs found
Map of New South Wales and Victoria [cartographic material] /
No full textMap of Southeastern Australia from the Tropic of Capricorn down to Victoria and featuring towns, roads, drainage and county boundaries. In addition, it includes boundaries of the settled districts, as well as the Intermediate Lands and the Unsettled Lands, counties proclaimed, counties proposed, and squatting districts. Relief is shown by hachures.; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.map-rm929
Feasibility study of geospatial mapping of chronic disease risk to inform public health commissioning
No full textThis final article is available for use under the terms of the Creative Commons Attribution Non-Commercial 2.0 Licence; see http://bmjopen.bmj.co
Warning signals and predator-prey coevolution
No full textTheories of the evolution of warning signals are typically expressed using analytic and computational models, most of which attribute aspects of predator psychology as the key factors facilitating the evolution of warning signals. Sherratt provides a novel and promising perspective with a model that considers the coevolution of predator and prey populations, showing how predators may develop a bias towards attacking cryptic prey in preference to conspicuous prey. Here, we replicate the model as an individual-based simulation and find, in accordance with Sherratt, that predators evolve a bias towards attacking cryptic prey. We then use a Monte Carlo simulation to calculate the relative survivorships of cryptic and conspicuous prey and stress that, as it stands, the model does not predict the evolution or stability of warning signals. We extend the model by giving predators continuous attack strategies and by allowing the evolution of prey conspicuousness: results are robust to the first modification but, in all cases, cryptic prey always enjoy a higher survivorship than conspicuous prey. When conspicuousness is allowed to evolve, prey quickly evolve towards crypsis, even when runaway coevolution is enabled. Sherratt's approach is promising, but other aspects of predator psychology, besides their innate response, remain vital to our understanding of warning signal
Rebuttal: "The funny current in the context of the coupled clock pacemaker cell system".
No full textSocial learning mechanisms compared in a simple environment
No full textSocial learning can be adaptive, but little is known about the underlying mechanisms. Many researchers have focused on imitation but this may have led to simpler mechanisms being underestimated. We demonstrate in simulation that imitative learning is not always the best strategy for a group-living animal, and that the effectiveness of any such strategy will depend on details of the environment and the animal's lifestyle. We show that observations of behavioural convergence or "traditions" might suggest effective social learning, but are meaningless considered alone
Edwin Noble Interview
No full textEdwin A. "Ned" Noble grew up in Bethel, Vermont and attended Tufts University after graduating from high school. He was drafted in 1944 and was assigned to the 1st Infantry Division, serving in the Ardennes, Rhineland and Central Europe; he subsequently served as Acting Battalion SGT MAJ during occupation duty in Nuremberg, Germany. He died at age 90 on January 3, 2013 in Washington, D.C
Noble gases in the Cameroon line and the He, Ne, and Ar isotopic compositions of high mu (HIMU) mantle
No full textUltramafic xenoliths, basaltic lavas, and CO2 gases from the Cameroon line volcanic chain provide the first characterization of combined He, Ne, and Ar isotopes in a high-time-integrated 238U/204Pb = μ (HIMU) magmatic system. Helium isotopic compositions typically range from 5.0 to 6.7 Ra, with an average of 6.3. These values are indistinguishable from the 3He/4He of other HIMU locales (Austral Islands, St. Helena). Neon isotopic compositions for xenoliths and CO2 gases are mid-ocean ridge basalt (MORB)-like, with a maximum 20Ne/22Ne of 11.87 and 21Ne/22Ne of 0.0508. Argon isotopic compositions in silicates range from atmospheric to 40Ar/36Ar = 4910±430 (crushing) and up to 16,300±1000 (single grain, laser step heating). The correlation between 20Ne/22Ne and 40Ar/36Ar in CO2 gases suggests a minimum 40Ar/36Ar = 1650±30 for the mantle-derived component. Uniform 3He/4He in silicates and in CO2 fluids across both the continental and oceanic sectors of the Cameroon line argues strongly for a negligible lithospheric contribution to noble gas isotopic compositions. This inference is supported by high 238U/3He in lherzolites, indicating that noble gases in these samples must have been recently introduced (<50,000 years ago) to the sample, most likely from the host magma. Ocean crust recycling models of mixing between MORB source regions and highly radiogenic slabs cannot produce the observed He and Ne isotopic compositions. Isolation and aging of MORB source mantle can generate the isotopic compositions but require extreme 3He/22Ne fractionation. Involvement of plume-derived gases, consistent with the lithophile element isotopic compositions, alleviates the need for strong 3He/22Ne fractionation. Closed-system aging of plume-derived heterogeneities can reproduce the data with minimum 3He/22Ne fractionation at reasonable 238U/3He ratios. However, diffusive exchange of He and to a lesser extent Ne between aged MORB source and aged plume veins could explain the occurrence of low 3He/4He compositions in all HIMU centers and the apparent low time-integrated 3He/22Ne of the Cameroon line
Effects of the topology of social networks on information transmission
No full textSocial behaviours cannot be fully understood without considering the network structures that underlie them. Developments in network theory provide us with relevant modelling tools. The topology of social networks may be due to selection for information transmission. To investigate this, we generated network topologies with varying proportions of random connections and degrees of preferential attachment. We simulated two social tasks on these networks: a spreading innovation model and a simple market. Results indicated that non-zero levels of random connections and low levels of preferential attachment led to more efficient information transmission. Theoretical and practical implications are discussed
Fundamental Study of nanostructured electro-catalysts with reduced noble metal content for PEM based water electrolysis
No full textIdentification and development of non-noble metal based electro-catalysts or electro-catalysts with significant reduction of expensive noble metal contents (E.g. IrO2, Pt) with comparable electrochemical performance as the standard noble metal/metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a major breakthrough in the generation of hydrogen by water electrolysis. Accomplishing such a system would not only result reduction of the overall capital costs of PEM based water electrolyzers, but also help attain the targeted hydrogen production cost [< $ 3.0 / gallon gasoline equivalent (gge)] comparable to conventional liquid fuels.
In line with these goals, it was demonstrated that fluorine doped IrO2 thin films and nanostructured high surface area powders display remarkably higher electrochemical activity, and comparable durability as pure IrO2 electro-catalyst for the oxygen evolution reaction (OER) in PEM based water electrolysis. Furthermore, corrosion resistant SnO2 and NbO2 support has been doped with F and coupled with IrO2 or RuO2 for use as an OER electro-catalyst. A solid solution of SnO2:F or NbO2:F with only 20 - 30 mol.% IrO2 or RuO2 yielding a rutile structure in the form of thin films and bulk nanoparticles displays similar electrochemical activity and stability as pure IrO2/RuO2. This would lead to more than 70 mol.% reduction in the noble metal oxide content. Novel nanostructured ternary (Ir,Sn,Nb)O2 thin films of different compositions have also been studied. It has been shown that (Ir0.40Sn0.30Nb0.30)O2 shows similar electrochemical activity and enhanced chemical robustness as compared to pure IrO2. F doping of the ternary (Ir,Sn,Nb)O2 catalyst helps in further decreasing the noble metal oxide content of the catalyst.
As a result, these reduced noble metal oxide catalyst systems would potentially be preferred as OER electro-catalysts for PEM electrolysis. The excellent performance of the catalysts coupled with its robustness would make them great candidates for contributing to significant reduction in the overall capital costs of PEM based water electrolyzers. This thesis provides a detailed fundamental study of the synthesis, materials, characterization, theoretical studies and detailed electrochemical response and potential mechanisms of these novel electro-catalysts for OER processes
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