Deliberating stratospheric aerosols for climate geoengineering and the SPICE project

Increasing concerns about the narrowing window for averting dangerous climate change have prompted calls for research into geoengineering, alongside dialogue with the public regarding this as a possible response. We report results of the first public engagement study to explore the ethics and acceptability of stratospheric aerosol technology and a proposed field trial (the Stratospheric Particle Injection for Climate Engineering (SPICE) ‘pipe and balloon’ test bed) of components for an aerosol deployment mechanism. Although almost all of our participants were willing to allow the field trial to proceed, very few were comfortable with using stratospheric aerosols. This Perspective also discusses how these findings were used in a responsible innovation process for the SPICE project initiated by the UK’s research councils

Photon assisted tunneling in pairs of silicon donors

Shallow donors in silicon are favorable candidates for the implementation of solid-state quantum computer architectures because of the promising combination of atomiclike coherence properties and scalability from the semiconductor manufacturing industry. Quantum processing schemes require (among other things) controlled information transfer for readout. Here we demonstrate controlled electron tunneling at 10 K from P to Sb impurities and vice versa with the assistance of resonant terahertz photons

Inventory of Karst Springs of Fayette County, Kentucky

The purpose of this publication is to document karst springs in Fayette County and provide a resource to help the county\u27s citizens avoid the geologic hazards associated with building near springs during future urban development. It may be used as an aid in locating potential groundwater discharge points in case of hazardous material spills, and to provide a foundation for future studies of the hydrogeology and karst geology of the Inner Bluegrass Region. It is also a basic historical record of the springs of Fayette County. Although over 350 springs are reported here, this inventory is not exhaustive. At the time of publication, about one-third of Fayette County had not yet been systematically inventoried. Fortunately, many springs in the unvisited areas were already known and recorded in the Kentucky Geological Survey (KGS) database and are included in this publication. The spring locations shown are mostly those discharging from karst conduits, but also included are a significant number of soil seeps or wet-weather springs (epikarstic), and some springs apparently discharging from fractures created by faults. The springs vary in size from seasonal seeps to perennial springs with base flows approaching 0.5 cubic foot per second. As the rapid pace of urban development continues in Fayette County, some natural springs reported here will become buried, and the records used to compile this publication will be an important resource in the future for separating natural from man-made groundwater discharge points

Early History of the Moon: Zircon Perspective

The Moon is believed to have formed from debris produced by a giant impact of a Mars sized body with the Earth (at around 4.51 Ga), forming a primitive body with a thick global layer of melt referred to as the Lunar Magma Ocean (LMO). The crystallization of LMO created internal stratification of the Moon forming main geochemical reservoirs. The surface features on the Moon were shaped by the subsequent collision with several large impactors during a short period of time (3.9-4.0 Ga). This process known as the Late Heavy Bombardment is supported by models of planetary motion, suggesting that rapid migration of giant planets could have triggered a massive delivery of planetesimals from the asteroid belt into the inner Solar System at about 3.9 Ga. Although, general chronology of LMO and LHB is well established using both long lived (U-Pb, Rb-Sr, Sm-147-Nd-143 and Ar-Ar) and extinct (Hf-182-W-182 and 146Sm-142Nd) isotope systems, some of these systems such as Ar-Ar are known to reset easily during secondary thermal overprints. As a result important details in the timing of LMO and LHB remain unresolved. In addition, the relative weakness of these systems under high T conditions can potentially bias the chronological information towards later events in the history of the Moon

Homes as machines: Exploring expert and public imaginaries of low carbon housing futures in the United Kingdom

Low carbon housing policies embody visions of the future that shape and constrain current choices between different technological pathways. These socio-technical imaginaries include expectations around new ways of living and interacting with technology, with implications for everyday lives. This paper investigates existing expert visions of low carbon housing, and explores these futures with members of the public; utilising empirical data from policy documents, expert interviews and public focus groups. Two competing expert visions of low carbon housing were identified: Passivhaus and Smart Homes. Whilst portrayed as divergent futures, both visions aimed to ‘design out’ the role of occupants, achieving emissions reductions through changes to the built environment and maintaining current lifestyles; a position that was reinforced by an imagined public that was unable or unwilling to accept the need for lifestyle change. This construction of the public did not consider the complex personal and cultural dimensions that influenced public acceptability of future housing: specifically surrounding themes of comfort, control and security that arose within the focus groups. The tensions arising between expert and public imaginaries highlight the difficulties that may surround any transition towards a low carbon future and demonstrate the need to work with, rather than around, the public

Electron effective mass in Al0.72_{0.72}Ga0.28_{0.28}N alloys determined by mid-infrared optical Hall effect

The effective electron mass parameter in Si-doped Al$_{0.72}$Ga$_{0.28}$N is determined to be $m^\ast=(0.336\pm0.020)\,m_0$ from mid-infrared optical Hall effect measurements. No significant anisotropy of the effective electron mass parameter is found supporting theoretical predictions. Assuming a linear change of the effective electron mass with the Al content in AlGaN alloys and $m^\ast=0.232\,m_0$ for GaN, an average effective electron mass of $m^\ast=0.376\,m_0$ can be extrapolated for AlN. The analysis of mid-infrared spectroscopic ellipsometry measurements further confirms the two phonon mode behavior of the E$_1$(TO) and one phonon mode behavior of the A$_1$(LO) phonon mode in high-Al-content AlGaN alloys as seen in previous Raman scattering studies

Creating a national citizen engagement process for energy policy.

This paper examines some of the science communication challenges involved when designing and conducting public deliberation processes on issues of national importance. We take as our illustrative case study a recent research project investigating public values and attitudes toward future energy system change for the United Kingdom. National-level issues such as this are often particularly difficult to engage the public with because of their inherent complexity, derived from multiple interconnected elements and policy frames, extended scales of analysis, and different manifestations of uncertainty. With reference to the energy system project, we discuss ways of meeting a series of science communication challenges arising when engaging the public with national topics, including the need to articulate systems thinking and problem scale, to provide balanced information and policy framings in ways that open up spaces for reflection and deliberation, and the need for varied methods of facilitation and data synthesis that permit access to participants' broader values. Although resource intensive, national-level deliberation is possible and can produce useful insights both for participants and for science policy.Natural Environment Research CouncilLeverhulme TrustWelsh GovernmentUS National Science Foundatio

Interpreting U–Pb data from primary and secondary features in lunar zircon

In this paper, we describe primary and secondary microstructures and textural characteristics found in lunar zircon and discuss the relationships between these features and the zircon U–Pb isotopic systems and the significance of these features for understanding lunar processes. Lunar zircons can be classified according to: (i) textural relationships between zircon and surrounding minerals in the host breccias, (ii) the internal microstructures of the zircon grains as identified by optical microscopy, cathodoluminescence (CL) imaging and electron backscattered diffraction (EBSD) mapping and (iii) results of in situ ion microprobe analyses of the Th–U–Pb isotopic systems. Primary zircon can occur as part of a cogenetic mineral assemblage (lithic clast) or as an individual mineral clast and is unzoned, or has sector and/or oscillatory zoning. The age of primary zircon is obtained when multiple ion microprobe analyses across the polished surface of the grain give reproducible and essentially concordant data. A secondary set of microstructures, superimposed on primary zircon, include localised recrystallised domains, localised amorphous domains, crystal–plastic deformation, planar deformation features and fractures, and are associated with impact processes. The first two secondary microstructures often yield internally consistent and close to concordant U–Pb ages that we interpret as dating impact events. Others secondary microstructures such as planar deformation features, crystal–plastic deformation and micro-fractures can provide channels for Pb diffusion and result in partial resetting of the U–Pb isotopic systems

Heavy Isotope Composition of Oxygen in Zircon from Soil Sample 14163: Lunar Perspective of an Early Ocean on the Earth

Thirty oxygen analyses of a large (sub-millimetre) zircon grain from the lunar soil sample 14163 have been determined using CAMECA 1270 ion microprobe. The sample 14163 was returned form the Fra Mauro region by Apollo 14 mission. Zircon grain of 0.6-0.8 mm in size extracted from the sample was imaged using CL detector fitted to the Philips Electron Microscope in order to reveal internal structure. Oxygen isotopes have been analysed during two sessions. The first set of data was collected using the original mount where the grain was set in the resin attached to the glass slide. This resulted in the two complications: (i) standard zircon has to be analysed from the separate mount and (ii) the lunar zircon grain was rased in the holder compared to the standard. In order to investigate, if the elevated oxygen compositions observed during this session could have resulted from this difference in geometric configuration during the standard and sample analyses, the lunar zircon was extracted from the original mount, remounted with the standard chip in the new resin disk and reanalysed during the second session. All analyses made during the first session show delta O-18 values heavier than 6.0%. The second set of data has a wider spread of delta O-18 values with some values as low as 5.6%. Nevertheless, a half of observed delta O-18 values in this set is also higher than 6.0%. Slightly lighter oxygen compositions observed during the second session indicate possible dependence of measured delta O-18 values on the geometry of analysed samples. Presence of zircons with similar heavy oxygen isotope compositions on the Moon, which neither had liquid water or felic crust similar to that on the Earth nor ever developed regime similar to plate tectonics, suggests that other mechanisms can be responsible for elevated delta O-18 values in zircons. This implies that there is no support for the presence of an ocean on the surface of the early Earth and as the ocean appears to be an essential ingredient for the plate tectonics, there is no basis for belief that this mechanism was operating in the early history of the planet

Epidemiology of unintentional fatal drowning among migrants in Australia

Objective: This study aimed to describe the epidemiology and risk factors contributing to drowning among migrants in Australia. Methods: A total population retrospective epidemiological study of unintentional drowning deaths in Australia between 1 July 2009 and 30 June 2019 of people born outside Australia (migrants). Cases were extracted from the National Coronial Information System. Descriptive statistics, chi-square and relative risk were calculated. Crude drowning rates were based on country of birth and population in Australia. Results: There were 572 migrant deaths over the study period, 28.9% of total drowning deaths, 82.9% were male. Twenty-one per cent were aged 25–34 years and 40.8% had lived in Australia for 20+ years. Migrants at highest risk of drowning were from: South Korea (2.63/100,000 95%CI: 0.85–8.25), Taiwan (2.29/100,000 95%CI: 0.27–13.44), and Nepal (2.15/100,000 95%CI: 0.23–11.55). Migrants were more likely to drown when around rocks (p<0.001) compared with Australian-born people, who most frequently drowned in rivers (p<0.001). Conclusions: Migrants are not over-represented in drowning statistics. However, unique trends were found for drowning among migrants based on country of birth and length of time in Australia. Implications for public health: Holistic drowning prevention strategies and policies are required to effectively lower drowning risk among migrant communities