Computer evaluation of topological formulas for network analysis

Single tree-finding program for digital computer evaluation of topological formulas for network analysi

The Opportunities and Limitations of Neutral Carbon Tariffs

Because carbon taxes can lead to loss of competitiveness, applying tariffs on imports from non-carbon-restricting countries helps address the cost disadvantage faced by producers in carbon-restricting countries. Such tariffs, known as border carbon adjustments ( BCAs ), can also help reduce possible carbon leakage, or the growth in foreign emissions due to increased production of carbon-intensive goods in non-carbon-restricting countries. We demonstrate that BCAs that do not exceed the burdens imposed by carbon taxation on domestic like products could be consistent with World Trade Organization ( WTO ) rules. However, neutral (i.e., nondiscriminatory) BCAs might still be inefficiently high from a global welfare perspective. This stems from the misaligned focus of BCAs on imports rather than production—the real cause of emissions. The discrepancy between neutrality and efficiency enables carbon-restricted industries to seek inefficiently high BCAs. Recognition of this discrepancy strengthens the case for multilateral alternatives that curb global carbon emissions. (JEL: F13, F18, H23

Unconventional magnetism in all-carbon nanofoam

We report production of nanostructured carbon foam by a high-repetition-rate, high-power laser ablation of glassy carbon in Ar atmosphere. A combination of characterization techniques revealed that the system contains both sp2 and sp3 bonded carbon atoms. The material is a novel form of carbon in which graphite-like sheets fill space at very low density due to strong hyperbolic curvature, as proposed for ?schwarzite?. The foam exhibits ferromagnetic-like behaviour up to 90 K, with a narrow hysteresis curve and a high saturation magnetization. Such magnetic properties are very unusual for a carbon allotrope. Detailed analysis excludes impurities as the origin of the magnetic signal. We postulate that localized unpaired spins occur because of topological and bonding defects associated with the sheet curvature, and that these spins are stabilized due to the steric protection offered by the convoluted sheets.Comment: 14 pages, including 2 tables and 7 figs. Submitted to Phys Rev B 10 September 200

The utility of computed tomography for recent-onset partial seizures in childhood

No Abstract. South African Medical Journal Vol. 96(9) (Part 2) 2006: 945-94

New urban governance: a review of current themes and future priorities

This review paper explores some of the key concepts, trends and approaches in contemporary urban governance research. Based on a horizon scan of recent literature and a survey of local government officials it provides a big picture on the topic and identifies areas for future research. Bridging the gap between the scholarly research focus and the perceptions and requirements of city administrators represents a major challenge for the field. Furthermore, because global and comparative research on urban governance is confronted with an absence of systematically collected, comparable data, the paper argues that future efforts will require experimenting with methodologies that can generate new empirical insights

National transport policy and cities: key policy interventions to drive compact and connected urban growth

This paper provides a foundation for national transport policy-makers to begin pragmatic but ambitious conversations about actions they can take to make cities more accessible

Cities and the governance of transport interfaces: Ethiopia’s new rail systems

This paper investigates the governance of transport infrastructure interfaces. These are connection or touching points that bring together different city systems, technical characteristics and governance regimes. The empirical evidence comes from Ethiopia's new rail systems and is based on experiences in two cities, the capital Addis Ababa and the second largest city Dire Dawa. The techno-spatial and organisational boundaries that define infrastructure interfaces are under-researched across disciplines. Yet it is at these hotspots of urban governance where many critical questions for cities arise: who governs, what to prioritise, how to coordinate? Based on a multiple case study approach, this paper combines socio-spatial analysis with institutional analysis of infrastructure governance. The findings include the identification of highly centralised and hierarchical governance and coordination dynamics, as well as the critical role of a new bureaucracy (the Ethiopian Railway Corporation) structured around core railway engineering competence rather than urban transport and development expertise. More generally, it is a techno-political alliance in Ethiopia which shapes urban development and the rollout of infrastructure at an unprecedented speed and scale