Studies of neutron stars at optical/IR wavelengths

In the last years, optical studies of Isolated Neutron Stars (INSs) have expanded from the more classical rotation-powered ones to other categories, like the Anomalous X-ray Pulsars (AXPs) and the Soft Gamma-ray Repeaters (SGRs), which make up the class of the magnetars, the radio-quiet INSs with X-ray thermal emission and, more recently, the enigmatic Compact Central Objects (CCOs) in supernova remnants. Apart from 10 rotation-powered pulsars, so far optical/IR counterparts have been found for 5 magnetars and for 4 INSs. In this work we present some of the latest observational results obtained from optical/IR observations of different types of INSs.     

Challenges to the development of carbon markets in China

China has introduced several pilot emission trading schemes to build the basis for a national scheme. The potential scale of this initiative raises prospects for a regional carbon trading network as a way to further engage other major Asian economies. However, the Chinese carbon markets rest upon a unique political-economic context and institutional environment that are likely to limit their development and viability. This article offers an overview of such structural economic and political constraints. Four main challenges are identified, namely, inadequate domestic demand, limited financial involvement, incomplete regulatory infrastructure, and excessive government intervention. The first two challenges concern economic dimensions and may be partially addressed by the incentives created by the newly introduced emission trading schemes. The other two are more deeply entrenched in the dominant political system and governing practice. They require fundamental changes to the ways in which the state and the market interact. The success of China's carbon market reform depends crucially on the ability of the ongoing efforts to transform the distorted state–market relationship.

Policy relevance

The burgeoning carbon markets offer opportunities for emissions mitigation at lower costs and enable circulation of a new form of capital, i.e. carbon credits, across borders. China accounts for a gigantic share of global GHG emissions and has the potential to significantly scale up these opportunities. There are clear implications for market developers and participants worldwide, including climate policy makers who attempt to link their emission trading schemes to other schemes, firms who seek to take advantage of the inexpensive carbon offsets generated in developing countries, international financial institutions who endeavour to establish their business in an emerging major carbon market, etc. This article can inform their decisions by identifying key issues that may undermine their ability to achieve these goals. Policy makers and stakeholders will benefit from this analysis, which shows how the Chinese carbon markets operate in ways that may be different from their experience elsewhere.     

A Combined Analytical and Numerical Approach for the Evaluation of Radial Loads on the Lining of Vertical Shafts

The evaluation of the load acting on a shaft support is of fundamental importance for the correct dimensioning of the structure. The load acting on the support can appear somewhat complex. One approach to define the load on the lining may be to use the convergence-confinement method (CCM) normally used in the tunneling design. This process involves intersecting the convergence-confinement (CC) curve with the support reaction line. However, in order to be able to adopt this technique, it is necessary to know the radial displacement of the shaft wall at the point in which the support is to be installed. Using the equations of Vlachopoulos and Diederichs (Rock Mech Rock Eng 42:131–146, 2009) the reaction line of the support can be calculated. Numerical models developed with Flac 2D v.6.0 considering the Mohr–Coulomb criterion and an ideal elasto-plastic behavior simulating stepwise excavation and support installation were developed. The relation between applied internal stress and radial displacement of the wall shaft, obtained by the numerical simulation was compared with the CC curve obtained by the CCM and it showed a good match between the two methods. However, an iterative procedure has also been used to insert the reaction line in the CC graph. The result shows lower initial displacements (and therefore greater radial stress) when compared with the values obtained by numerical calculation with the axisymmetric model. It is therefore recommended the combined use of the CCM (analytical method) and the axisymmetric numerical model (step by step simulation) to obtain the values of the final load on the lining and the final plastic radius, necessary for the correct design of supporting structures on the shaft wall.     

Confidence and Trust in Public Institution Natural Hazards Management: Case Studies in Urban and Rural China

This research aims to investigate the extent to which urban and rural residents trust grassroots-level institutions and how this might affect community resilience to environmental change in China. It focuses on the commitments of institutional actors and their capacities to manage natural hazards and coordinate the community's response. Semistructured interviews were conducted with megacity (Tianjin) and remote village (Wolong) residents in China. We found that public confidence in grassroots-level institutions is limited due to inherent constraints on resources and power. Residents of Wolong tend to recognize the commitment and role of those institutions in connecting individuals with one another, whereas their urban counterparts in Tianjin remain skeptical. Issues of solidarity might account for this difference. These findings will have implications for state–society cooperation and disaster risk comanagement in both urban and rural China.     

Isotope spectroscopy

The measurement of isotopic ratios provides a privileged insight both into nucleosynthesis and into the mechanisms operating in stellar envelopes, such as gravitational settling. In this article, we give a few examples of how isotopic ratios can be determined from high‐resolution, high‐quality stellar spectra. We consider examples of the lightest elements, H and He, for which the isotopic shifts are very large and easily measurable, and examples of heavier elements for which the determination of isotopic ratios is more difficult. The presence of ⁶Li in the stellar atmospheres causes a subtle extra depression in the red wing of the ⁷Li 670.7 nm doublet which can only be detected in spectra of the highest quality. But even with the best spectra, the derived ⁶Li abundance can only be as good as the synthetic spectra used for their interpretation. It is now known that 3D non‐LTE modelling of the lithium spectral line profiles is necessary to account properly for the intrinsic line asymmetry, which is produced by convective flows in the atmospheres of cool stars, and can mimic the presence of ⁶Li. We also discuss briefly the case of the carbon isotopic ratio in metal‐poor stars, and provide a new determination of the nickel isotopic ratios in the solar atmosphere. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

An integrative assessment of water vulnerability in First Nation communities in Southern Ontario,Canada

Assessing vulnerability related to water is a global concern and especially important to populations experiencing multiple exposures and sensitivities. Approaches are required that span social and physical concerns, and that bridge multiple types and forms of knowledge. This research investigates the water vulnerability of three First Nation communities in Ontario, Canada. A collaborative process was used to build an integrative understanding of water vulnerability, develop an associated instrument, and undertake the community scale assessments. Results from the assessment provided communities with a comprehensive overview of water vulnerability, and pointed to gaps in knowledge and specific areas where attention was needed. Conducting assessments at a community scale following the methodology employed in this research responds to the need for integration and context sensitivity when engaging in water vulnerability assessments and introduces innovations to existing assessment tools. A holistic approach to water vulnerability assessment provided decision-makers with the context-specific details and empirical insights they require to prioritize issues and allocate resources.     

Analytical solutions for stresses and displacements around tunnels driven in cross-anisotropic rocks

In this paper, closed-form solutions for the stresses and displacements around unlined circular tunnels excavated in an elastic, orthotropic (cross-anisotropic) medium are developed. The effect of both the elastic parameters characterizing the behaviour of the medium and the anisotropy of the initial stress system on the stresses and displacements induced are evaluated. An example of utilizing the theoretical solution for design analysis is given. For convenience of application, design charts are prepared for the determination of stresses and displacements for given values of initial stresses and the elastic parameters. Copyright © 1999 John Wiley & Sons, Ltd.     

Semi-empirical prediction method for monthly precipitation prediction based on environmental factors and comparison with stochastic and machine learning models

ABSTRACT

Precipitation prediction is central in hydrology and water resources planning and management. This paper introduces a semi-empirical predictive model to predict monthly precipitation and compares its predictive skill with those of machine learning (ML) methods. The stochastic method presented herein estimates monthly precipitation with one-step-ahead prediction properties. The ML predictive skill of the algorithms is evaluated by predicting monthly precipitation relying on the statistical association between precipitation and environmental and topographic factors. The semi-empirical predictive model features non-negative matrix factorization (NMF) for investigating the influence of multiple predictor variables on precipitation. The semi-empirical predictive model’s parameters are optimized with the hybrid genetic algorithm (GA) and Levenberg-Marquardt algorithm (LM), or GALMA, yielding a validated model with high predictive skill. The methodologies are illustrated with data from Hubei Province, China, which comprise 27 meteorological station datasets from 1988–2017. The empirical results provide valuable insights for developing semi-empirical rainfall prediction models.