First ENA observations at Mars: ENA emissions from the martian upper atmosphere

The neutral particle detector (NPD) on board Mars Express has observed energetic neutral atoms (ENAs) from a broad region on the dayside of the martian upper atmosphere. We show one such example for which the observation was conducted at an altitude of 570 km, just above the induced magnetosphere boundary (IMB). The time of flight spectra of these ENAs show that they had energies of 0.2-2 keV/amu, with an average energy of ∼1.1 keV/amu. Both the spatial distribution and the energy of these ENAs are consistent with the backscattered ENAs, produced by an ENA albedo process. This is the first observation of backscattered ENAs from the martian upper atmosphere. The origin of these ENAs is considered to be the solar wind ENAs that are scattered back by collision processes in the martian upper atmosphere. The particle flux and energy flux of the backscattered ENAs are and , respectively.     

Welcome to Woodside: Inverbrackie Alternative Place of Detention and performances of belonging in Woodside,South Australia,and Australia

Alternative Places of Detention (APODs) are a new way of detaining asylum seekers in Australia. The establishment of APODs creates a new formal structure of belonging in Australia which challenges everyday practices of belonging and senses of belonging at the local and national scale. This paper examines practices of belonging which emerged following the establishment of the Inverbrackie APOD in Woodside, South Australia. Using a critical discourse analysis approach, informed by the insights of theories of performativity, this research explores the competing stories of two broadly defined groups (opponents and supporters of Inverbrackie) engaged in a dialogue about asylum seekers, refugees, immigration detention and belonging. While opposition to the APOD was vocal and frequent in the lead-up to the establishment of the detention centre, once the Inverbrackie APOD became operational opponents’ voices began to fade. On the other hand, supporters continued to say things—and more importantly continued to do things—to nurture belonging for asylum seekers in Inverbrackie, Woodside, and Australia.     

Street Versus Rooftop Level Concentrations of Fine Particles in a Cambridge Street Canyon

Dispersion of particles, as evidenced by changes in their number distributions (PNDs) and concentrations (PNCs), in urban street canyons, is still not well understood. This study compares measurements by a fast-response particle spectrometer (DMS500) of the PNDs and the PNCs (5–1000 nm, sampled at 1 Hz) at street and rooftop levels in a Cambridge UK street canyon, and examines mixing, physical and chemical conversion processes, and the competing influences of traffic volume and rooftop wind speed on the PNDs and the PNCs in various size ranges. PNCs at street level were ≈6.5 times higher than at rooftop. Street-level PNCs followed the traffic volume and decreased with increasing wind speed, showing a larger influence of wind speed on 30–300 nm particles than on 5–30 nm particles. Conversely, rooftop PNCs in the 5–30 nm size range increased with wind speed, whereas those for particles between 30 and 300 nm did not vary with wind speed.     

Titanium in subduction zone fluids: First insights from abinitio molecular metadynamics simulations

The preferential incorporation of High-Field-Strength Elements (HFSE) in rutile (TiO₂), combined with its supposed stability in subduction zone settings, make it an ideal candidate to explain the low HFSE concentrations in subduction-derived magmas. The solubility behaviour of rutile is key to these arguments, but at present experimental and field-based evidence are contradictory.We have used abinitio molecular (meta)dynamics to investigate the coordination environment of Ti(IV) in pure water at 300 and 1000 K and densities ranging from 900-1260 kg m⁻³ (approximate pressures 0.9-3.6 GPa). In all high temperature simulations, the long-range structure of the solvent indicates a breakdown of the hydrogen bonding network as expected for supercritical water. The five-fold coordination of titanium to water is energetically most favourable in aqueous fluids at room temperature and pressure, separated from four and six-fold configurations by ∼175 and ∼200 kJ mol⁻¹, respectively. The average first shell Ti-O distance is 2.00 Å, in excellent agreement with bond lengths obtained from experiments. At similar densities and 1000 K, titanium is on average six-fold coordinate with water, and shows some degree of water dissociation in the first hydration shell. This coordination environment is remarkably persistent with increasing density from 1021 to 1260 kg m⁻³ at constant temperature (1000 K). At lower densities, however, (900 kg m⁻³ at 1000 K), the coordination with first shell water molecules is less than five. The observed coordination changes could promote association of titanium with peralkaline or peraluminous domains in the aqueous fluid, and thereby explain field-and laboratory based evidence of enhanced HFSE concentrations.This study demonstrates that abinitio molecular dynamics has considerable potential to access details of element behaviour in aqueous fluids at geologically relevant conditions that are impossible to examine otherwise. Changes in the solvent structure due to density variations lead to differences in solvent behaviour allowing access to new domains for fluid-solid interaction. Moreover, changes in the solvent structure are strongly linked to the effectiveness of element solvation.     

Origin of the patchy emission pattern at the ZERT CO<Subscript>2</Subscript> release test

A numerical experiment was carried out to test whether the patchy CO₂ emission patterns observed at the Zero Emissions Research and Technology release facility are caused by the presence of packers that divide the horizontal injection well into six CO₂-injection zones. A three-dimensional model of the horizontal well and cobble–soil system was developed and simulations using TOUGH2/EOS7CA were carried out. Simulation results show patchy emissions for the seven-packer (six-injection-zone) configuration of the field test. Numerical experiments were then conducted for the cases of 24 packers (23 injection zones) and an effectively infinite number of packers. The time to surface breakthrough and the number of patches increased as the number of packers increased suggesting that packers and associated along-pipe flow are the origin of the patchy emissions. In addition, it was observed that early breakthrough occurs at locations where the horizontal well pipe is shallow and installed mostly in soil rather than the deeper cobble. In the cases where the pipe is installed at shallow depths and directly in the soil, higher pipe gas saturations occur than where the pipe is installed slightly deeper in the cobble. It is believed this is an effect mostly relevant to the model rather than the field system and arises through the influence of capillarity, permeability, and pipe elevation of the soil compared to the cobble adjacent to the pipe.     

Efforts to reduce sea turtle bycatch in the shrimp fishery in Northeastern Brazil through a co-management process

The neritic waters of the state of Sergipe in Northeastern Brazil is adjacent to the main nesting area of the olive ridley sea turtles (Lepidochelys olivacea) in the Western Atlantic Ocean and an important area for shrimp trawl fishery. To address the problem of incidental mortality of sea turtles captured during trawling and reduce the risk of overexploitation of shrimp stocks, Projeto TAMAR/ICMBio, a Brazilian sea turtle conservation program, has adopted two main strategies: (1) the implementation of a marine monitoring program and (2) active participation in local forums. This paper describes the conflicts among stakeholders, the arrangements and established mechanisms of negotiation aimed to protect sea turtles and shrimp grounds, and strategies to reduce conflicts between user groups. The analysis of this co-management process highlights the importance of stakeholder participation in resource management decision-making through a cooperative process, the role assumed by non-governmental organizations as mediators, and the factors that influence this system. The key factors and actions learnt from the current study include clear identification of the conflicts, identification of stakeholders – both local and external, and local leaders, encouragement of actors and leaders to participate, support and strengthening of local groups, legitimization of the discussion forums through involvement with government, formalization of decisions taken through legislation, and monitoring of the management efficacy.     

The metasomatic development of zoned ultrabasic bodies in Unst,Shetland

Read (1934b) described the mineralogy and regional setting of spectacularly zoned ultrabasic bodies occurring in Unst, Shetland. Chemical and phase compositional data are presented here for a selection of samples taken from each of the several monomineralic zones.The phase sequence and elemental distribution are discussed in some detail since both are complicated. It is shown that virtually all distributional features may be explained on the basis of a diffusion model: transport most probably having occurred via aqueous solutions in pore space.The present configurations represent frozen reaction intermediates. Controls upon the nature and extent of reaction are analysed. Certain features may be explained on the basis of local equilibrium thermodynamics. These arguments, however, are inadequate. Fairly simple kinetic considerations lead to a much more satisfactory analysis.Some of the problems associated with concepts of element mobility are discussed briefly.