Prospects and requirements for measurements of extragalactic γ-ray lines

A brief summary is presented of requirements for the measurements of extragalactic γ-ray lines. The electron-positron annihilation line at 511 keV represents the best prospect, and although this line is greatly broadened in active galactic nuclei, a narrow line should be present in clusters of galaxies and radio lobes as a result of prior AGN activity. The strongest fluxes should be of the order of 10⁻⁴ photons cm⁻² s⁻¹ from the closest extended sources.     

Linguistics,geography, and the potential of Australian island toponymies

Australian placename studies have focused on documenting toponymic histories and issues of concern mainly for placename taxonomy and etymology. Language-external factors such as geographical and environmental conditions have not been of great interest to Australian toponymists. This article assesses the role of geographical and environmental constriction of island places on their toponymy. It considers whether or not island locations breed ‘insular toponymies’ or placename histories inaccessible and not readily accessible to outsider researchers. The case studies are Norfolk Island, South Pacific, and Dudley Peninsula, South Australia, two island environments within political Australia. The results demonstrate that the degree of insularity of the toponymies of the two island environments is driven more by geographical and social factors than linguistic elements. The results put forward several ways in which geographers, linguists, historians, toponymists, and Australian studies scholars could work together and collaborate to better understand Australian island places.     

Transient analysis of excavations in soil

A finite element approach is used to assess the transient stability of excavation in elasto-plastic soils. Stability is shown to be a function of the rate of excavation, the soil permeability and the drainage path lengths. Sequential excavation has been modelled rigorously in the finite element analysis, together with the transient effects through a fully coupled Biot formulation. Results are presented which demonstrate the effects of the rate of excavation and permeability on stability. Both drained and undrained behaviour of the problem are retrieved as special cases of the transient analysis, and comparisons made with classical solutions where available.     

Radiative and collisional processes in CNA 2Π i

In the last four years we have carried out a number of studies on the radiative and collisional processes in theA ² _i state of CN. Many of these of interest to those studying planetary atmospheres, comets and solar spectra are summarized in this paper. Data for CNA ² _i fluorescence lifetimes and quenching rates, and collisional energy transfer between CNA ² _i andX ²₊ are reported. Detailed comparisons and a discussion of the results may be found in several already published papers.     

Language contact and ‘the Catch’: Norfolk Island fishing ground names

The author uses Norf'k fishing ground names on Norfolk Island (South Pacific) to illustrate how toponyms can be exposed to geographic, anthropological, and linguistic scrutiny. The grammar of the names demonstrates how Norf'k, the language of the Pitcairn descendants, typifies an esoteric insider language because of its ecologically connected toponyms and pragmatic determinants. Norf'k fishing ground names vary in their linguistic form and hence in their geography and spatiality. The toponymic and linguistic landscape of Norfolk Island reveals several processes that are significant for understanding sea-based geographies and the intertwining of creole languages, other contact languages, and the environment.     

Spatial length scale analysis of data from observations and a model of the Iceland-Faeroes front

Hydrographic data from the Iceland-Faeroes Ridge region, covering an area of 59°–69° north and 0°–20° west, have been subjected to a spatial data analysis. The analysis consists of the two-dimensional spectral method (2D-FFT) and the empirical eigenfunction method (EOF). Results from the two methods show good agreement indicating that the significant length scales for horizontal variability present in the data have wavelengths of approximately 339 km, 72 km and 37 km. These wavelengths relevant to the Iceland-Faeroes front are interpreted as the sizes respectively of the warm water intrusion from the south of the front with a diameter of half the wavelength (i.e.,?169 km), and the meander-like and eddy-like features. Predictions of the same frontal system have also been made using a realistic numerical model to provide hydrographic outputs similar to the observations. The hydrographic outputs from the model have been subjected to the same 2D-FFT method to establish the spatial length scale present in the model predictions. A comparison of results from a spectral data analysis between the field measurements and the model predictions shows that the model can predict the sizes of the meander-like and the eddy-like features quite accurately. However, predictions of frontal orientation, frontal slopes and size of the warm water intrusion still require further study. The work presented also demonstrates the importance of spatial statistics in oceanographic research, particularly in ocean predictability studies.     

Stability of earth slopes. Part I: two‐dimensional analysis in closed‐form

A closed‐form solution (CFS) satisfying both equilibrium of moments and forces for the stability analysis of earth slopes in 2D is proposed. The sliding surface is assumed circular and treated as a rigid body, allowing the internal state of stress to be ignored. The proposed solution can be applied to both homogenous and non‐homogenous slopes of either simple or complex geometry, and can also deal with any kind of additional loading. The method is based on the fact that, all possible forces acting on the slope can be projected onto the failure surface where they are broken into driving and resisting ones. Comparison of the safety factors obtained by the proposed CFS and those obtained by traditional limit equilibrium methods, as applied to several test examples, indicates that the proposed method is more conservative, whereas moreover, it gives a more realistic point of view for the formation of tension crack in slopes. Copyright © 2012 John Wiley & Sons, Ltd.     

Non‐linear response of current‐meter compasses: Research note

Abstract

A non‐linear response in current‐meter compasses is examined in terms of its effect on the measured residual current. It is shown that, even for a compass response within typical manufacturers’ specifications, the induced errors are important for regions where the residual speed is less than about 10% of the peak tidal current. In an M₂ current, the non‐linearity also induces an M₄ signal, but this is not sufficiently large to be easily detected by tidal analyses.     

Synergies and tradeoffs in how managers,scientists, and fishers value coral reef ecosystem services

Managing ecosystems in a changing environment faces the challenge of balancing diverse competing perspectives on which ecosystem services – nature's benefits – to prioritize. Consequently, we measured and compared how different stakeholders (managers, scientists and fishers) prioritize specific coral reef ecosystem services. Managers’ priorities were more aligned with scientists’ priorities but all stakeholder groups agreed that fishery, education, and habitat were high priorities. However, stakeholder groups differed in the extent to which they prioritized certain services. Fishers tended to assigned greater estimates to fishery and education, managers to culture, and scientists to coastal protection. Furthermore, using network analysis to map the interactions between stakeholders’ priorities, we found distinct synergies and trade-offs in how ecosystem services were prioritized, representing areas of agreement and conflict. In the fishers’ network, trade-offs emerged between two services, both of a higher priority, such as fishery and habitat. Conversely, in the scientists’ network, trade-offs emerged between services of a higher and lower priority, such as habitat and culture. The trade-offs and synergies that emerged in the managers’ network overlap with both fishers’ and scientists’ suggesting a potential brokering role that managers can play in balancing both priorities and conflicts. We suggest that measuring ecosystem service priorities can highlight key areas of agreement and conflict, both within and across stakeholder groups, to be addressed when communicating and prioritizing decisions.