Dissociative recombination contributions to I(5577) and I(6300) [OI] and NmF2 enhancements resulting from moderate proton PCA events

We investigate the dissociative recombination contribution to I(5577) and I(6300) of [OI] as a function of low energy cutoff for two measured solar proton spectra. The volume ionization rate profiles used in the calculation are obtained using a detailed atomic cross section approach in the continuous slowing down approximation. The ratio of the dissociative recombination contribution to the direct impact contribution for both the 5577 Å and 6300 Å [OI] emissions is found to be dependent upon the low energy cutoff. This ratio has a nominal value of ～2.0 for the 5577 Å [OI] emission and ～0.25 for the 6300 Å [OI] emission. The I(5577)/I(3914) and I(6300)/I(3914) ratios including the direct and dissociative recombination contributions are strongly dependent upon the low energy cutoff of the spectrum. We have also investigated F-layer enhancements resulting from the low energy spectrum component. For the Mizera et al. (1972) spectrum with a low energy cutoff of 12.4 keV, we find an N_mF2 of ～4.5 × 10³ electrons/cm³ or about 10 per cent of the ionization required to maintain the dip pole at a value of 5 × 10⁴ electrons/cm³. Extension of the cutoff to 1 keV results in ～1 × 10⁴ electrons/cm³, or about 20 per cent of the required maintenance ionization.     

Post-Kyoto greenhouse gas inventories: production versus consumption

For the long-term stabilization of greenhouse gas (GHG) concentrations it is important that post-Kyoto policy has broad participation to ensure environmental integrity. Many post-Kyoto frameworks have been debated, but surprisingly approaches that focus on consumption have received little attention in the climate change literature despite broader interest in other areas. In this article we extend the argument for constructing GHG inventories using a country’s consumption rather than production. First, we argue that constructing GHG inventories using a country’s economic activity instead of geographic territory solves allocation issues for international activities such as international transportation and carbon capture and storage. Second, we argue that consumption-based GHG inventories have many advantages over production-based inventories. The main advantages are to address carbon leakage, reduce the importance of emission commitments for developing countries, increase options for mitigation, encourage environmental comparative advantage, address competitiveness concerns, and naturally encourage technology diffusion.     

Thermal maturity and organic composition of Pennsylvanian coals and carbonaceous shales, north-central Texas: Implications for coalbed gas potential

Thermal maturity was determined for about 120 core, cuttings, and outcrop samples to investigate the potential for coalbed gas resources in Pennsylvanian strata of north-central Texas. Shallow (< 600 m; 2000 ft) coal and carbonaceous shale cuttings samples from the Middle-Upper Pennsylvanian Strawn, Canyon, and Cisco Groups in Archer and Young Counties on the Eastern Shelf of the Midland basin (northwest and downdip from the outcrop) yielded mean random vitrinite reflectance (R_o) values between about 0.4 and 0.8%. This range of R_o values indicates rank from subbituminous C to high volatile A bituminous in the shallow subsurface, which may be sufficient for early thermogenic gas generation. Near-surface (< 100 m; 300 ft) core and outcrop samples of coal from areas of historical underground coal mining in the region yielded similar R_o values of 0.5 to 0.8%. Carbonaceous shale core samples of Lower Pennsylvanian strata (lower Atoka Group) from two deeper wells (samples from ~ 1650 m; 5400 ft) in Jack and western Wise Counties in the western part of the Fort Worth basin yielded higher R_o values of about 1.0%. Pyrolysis and petrographic data for the lower Atoka samples indicate mixed Type II/Type III organic matter, suggesting generated hydrocarbons may be both gas- and oil-prone. In all other samples, organic material is dominated by Type III organic matter (vitrinite), indicating that generated hydrocarbons should be gas-prone. Individual coal beds are thin at outcrop (< 1 m; 3.3 ft), laterally discontinuous, and moderately high in ash yield and sulfur content. A possible analog for coalbed gas potential in the Pennsylvanian section of north-central Texas occurs on the northeast Oklahoma shelf and in the Cherokee basin of southeastern Kansas, where contemporaneous gas-producing coal beds are similar in thickness, quality, and rank.     

The vertical structure of planet-induced gaps in protoplanetary discs

Giant planets embedded in circumstellar discs are expected to open gaps in these discs. We examine the vertical structure of the gap edges. We find that the planet excites spiral arms with significant (Mach number of a half) vertical motion of the gas, and discuss the implications of these motions. In particular, the spiral arms will make the edge appear 'puffed up' relative to the bulk of the disc. Infrared observations (sensitive to dust) would be dominated by the light from the thick inner edge of the disc. Submillimetre observations (sensitive to gas velocities) would appear to be hot in 'turbulent' motions (actually the ordered motion caused by the passage of the spiral arms), but cold in chemistry. Resolved submillimetre maps of circumstellar discs might even be able to detect the spiral arms directly.     

Perceptions of local community members towards foreign aid: A case study of Vava'u,Tonga

Foreign aid has arguably played a significant role in the economic development of the Pacific Island countries. Tonga is deemed to have succeeded in implementing the principles of the Paris Declaration of 2005, especially Ownership, Alignment and Harmonisation, by aid funding channelled through state institutions. Nevertheless, it is still unknown if the aid effect has reached civil society, and how community members perceive aid. This article examines the perceptions of community members towards foreign aid, using the case study of the archipelago of Vava'u, Tonga.     

Pure elastic stiffness of sand represented by response envelopes derived from cyclic triaxial tests with local strain measurements

Acta Geotechnica - The elastic stiffness of a fine sand at small to moderate strains ( $$\varepsilon \le 2 \times 10^{-4}$$ ) has been studied based on cyclic triaxial tests on cube-shaped samples...