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

Social structures of urban governance: strategic spatial planning in Addis Ababa

Focusing on strategic planning for spatial development, this paper explores the social structures that underpin urban governance in Addis Ababa, Ethiopia. To bridge the divide in the literature between studies that are narrowly focused on public service networks (typically more quantitative) and broader studies of urban governance (typically more qualitative), we use a social network analysis approach based on structured interviews to chart the actors and connections that influence the strategic planning process. Our results show that the governance network in this city is very homogeneous and centralised. The majority of actors at the core of strategic decision-making are city government entities, where most ties are structured around the Addis Ababa City Plan Commission and the mayor. With few exceptions (notably, the prime minister), other tiers of government, civil society organisations, the private sector and international donors are mostly peripheral. The fact that some powerful actors – such as international investors and the ruling coalition parties – are also playing a marginal role in the network may threaten governance stability and coherence. Although the mayor is a very powerful actor at the city level, the structural features of the governance network and the institutional power of the prime minister allow them to streamline their influence over the city’s future. The current governance regime for strategic spatial planning in Addis Ababa seems to privilege the effectiveness of the developmental agenda over the inclusiveness of the governing process. This has troubling implications for participatory development and the emergence of a more democratic society

Integrating water quality models in the High Level Architecture (HLA) environment

International audienceHLA (High Level Architecture) is a computer architecture for constructing distributed simulations. It facilitates interoperability among different simulations and simulation types and promotes reuse of simulation software modules. The core of the HLA is the Run-Time Infrastructure (RTI) that provides services to start and stop a simulation execution, to transfer data between interoperating simulations, to control the amount and routing of data that is passed, and to co-ordinate the passage of simulated time among the simulations. The authors are not aware of any HLA applications in the field of water resources management. The development of such a system is underway at the UFZ -Centre for Environmental Research, Germany, in which the simulations of a hydrodynamic model (DYNHYD), eutrophication model (EUTRO) and sediment and micro-pollutant transport model (TOXI) are interlinked and co-ordinated by the HLA RTI environment. This configuration enables extensions such as (i) "cross-model" uncertainty analysis with Monte Carlo Analysis: time synchronisation allows EUTRO and TOXI simulations to be made after each successive simulation time step in DYNHYD, (ii) information transfer from EUTRO to TOXI to compute organic carbon fractions of particulate matter in TOXI, (iii) information transfer from TOXI to EUTRO to compute extinction coefficients in EUTRO and (iv) feedback from water quality simulations to the hydrodynamic modeling

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 impact of subspecialty services on healthcare delivery - a community health centre based study

Objectives. The objective was to evaluate the role of a paediatric surgical consultant at a primary health care facility. Design. Descriptive and prospective. Setting. In the process of planning and implementation of the 2010 health plan of the Provincial Government of the Western Cape, a shift occurred in the delivery of health care to children from a provincially based hospital system to a municipally based primary health care system. To contribute towards enabling this process, the Department of Paediatric Surgery at Red Cross War Memorial Children’s Hospital established a paediatric surgical day clinic at a local community health centre during 2001. Subjects. Information was obtained from patient data sheets containing details of consultations at the sub-specialist surgical clinic at Michael Mapongwana Community Health Centre. Results. Over a 58-month period 1 171 children were seen, of whom 655 were male and 427 female. Their ages ranged from 0 to 19 years, the largest group being under 1 year. Eighty per cent of patients were accompanied by their mothers. The correct diagnosis was established by the nurse practitioners in 71%. General paediatric surgical conditions predominated, followed by medical, dermatological, orthopaedic, trauma, otolaryngo-pharyngology, infectious diseases, ophthalmology, urology, neurosurgery, malignancy and maxillofacial conditions. The details are set out in the report. In total 597 patients were referred directly to an appropriate care facility and 574 patients could be managed entirely at the clinic level. Conclusions. This study demonstrated the significant public health problem of paediatric surgical disease. It emphasised the preventative and cost-effective role of a surgical clinic at primary health care level. The clinic allowed for timely surgical intervention in 65% of surgical cases, thereby decreasing inappropriate tertiary referrals. We believe that bringing specialists into the community can only strengthen the 2010 health care plan

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