Constraining the Temperature of Impact Melt from the Mistastin Lake Impact Structure Using Zircon Crystal Structures

Impact melt is a product of hyper-velocity impact events formed by the instantaneous melting of near-surface target rocks. Constraining the temperature of impact melt is vital to understanding its prograde heating and cooling history, which can have implications for inferring the environment of early Earth ~4.0 billion years ago when microbial life potentially arose. To date, only one datum on the initial impact melt temperature has been derived by Timms et al. These authors studied zirconia microstructures and crystallographic orientations that revealed the former presence of cubic zirconia, found in a black impact glass at the Mistastin Lake impact structure, Canada. The presence of cubic zirconia indicates a minimum temperature for the impact melt of >2370C from the dissociation temperature of zircon to cubic zirconia and liquid SiO2. With only one temperature datum, it is still difficult to constrain the entire temperature range experienced during the impact melting process; from its instantaneous formation to thermal equilibrium with the cold clasts collected along the crater floor and walls. In addition, obtaining a temperature value from only one type of impactite limits the inferred temperature range, because each impactite experiences a different cooling history. In this study, we present a preliminary investigation of 61 zircon crystals, 14 of which are similar to those studied by Timms et al., from the Mistastin Lake impact structure. To acquire a more accurate temperature profile representative of impact melt, zircon crystals were collected from different types of impactites containing impact melt, including additional samples of the black impact glass studied by Timms et al

Geophysical characteristics and crustal structure of greenstone terranes: Canadian Shield

Geophysical studies in the Canadian Shield have provided some insights into the tectonic setting of greenstone belts. Greenstone belts are not rooted in deep crustal structures. Geophysical techniques consistently indicate that greenstones are restricted to the uppermost 10 km or so of crust and are underlain by geophysically normal crust. Gravity models suggest that granitic elements are similarly restricted, although magnetic modelling suggests possible downward extension to the intermediate discontinuity around approx. 18 km. Seismic evidence demonstrates that steeply-dipping structure, which can be associated with the belts in the upper crust, is not present in the lower crust. Horizontal intermediate discontinuities mapped under adjacent greenstone and granitic components are not noticeably disrupted in the boundary zone. Geophysical evidence points to the presence of discontinuities between greenhouse-granite and adjacent metasedimentary erranes. Measured stratigraphic thicknesses of greenstone belts are often twice or more the vertical thicknesses determined from gravity modelling. Explantations advanced for the discrepancy include stratigraphy repeated by thrust faulting and/or listric normal faulting, mechanisms which are consistent with certain aspects of conceptual models of greenstone development. Where repetition is not a factor the gravity evidence points to removal of the root zones of greenstone belts. For one region, this has been attributed to magmatic stopping during resurgent caldera activity

The minimum energy expenditure shortest path method

This article discusses the addition of an energy parameter to the shortest path execution process; namely, the energy expenditure by a character during execution of the path. Given a simple environment in which a character has the ability to perform actions related to locomotion, such as walking and stair stepping, current techniques execute the shortest path based on the length of the extracted root trajectory. However, actual humans acting in constrained environments do not plan only according to shortest path criterion, they conceptually measure the path that minimizes the amount of energy expenditure. On this basis, it seems that virtual characters should also execute their paths according to the minimization of actual energy expenditure as well. In this article, a simple method that uses a formula for computing vanadium dioxide ($VO_2$) levels, which is a proxy for the energy expenditure by humans during various activities, is presented. The presented solution could be beneficial in any situation requiring a sophisticated perspective of the path-execution process. Moreover, it can be implemented in almost every path-planning method that has the ability to measure stepping actions or other actions of a virtual character

Sub-kiloparsec Imaging of Cool Molecular Gas in Two Strongly Lensed Dusty, Star-Forming Galaxies

We present spatially-resolved imaging obtained with the Australia Telescope Compact Array (ATCA) of three CO lines in two high-redshift gravitationally lensed dusty star-forming galaxies, discovered by the South Pole Telescope. Strong lensing allows us to probe the structure and dynamics of the molecular gas in these two objects, at z=2.78 and z=5.66, with effective source-plane resolution of less than 1kpc. We model the lensed emission from multiple CO transitions and the dust continuum in a consistent manner, finding that the cold molecular gas as traced by low-J CO always has a larger half-light radius than the 870um dust continuum emission. This size difference leads to up to 50% differences in the magnification factor for the cold gas compared to dust. In the z=2.78 galaxy, these CO observations confirm that the background source is undergoing a major merger, while the velocity field of the other source is more complex. We use the ATCA CO observations and comparable resolution Atacama Large Millimeter/submillimeter Array dust continuum imaging of the same objects to constrain the CO-H_2 conversion factor with three different procedures, finding good agreement between the methods and values consistent with those found for rapidly star-forming systems. We discuss these galaxies in the context of the star formation - gas mass surface density relation, noting that the change in emitting area with observed CO transition must be accounted for when comparing high-redshift galaxies to their lower redshift counterparts.Comment: 14 pages, 7 figures; accepted for publication in Ap

Type 2 diabetes remission: economic evaluation of the DiRECT/Counterweight‐Plus weight management programme within a primary care randomized controlled trial

Aim: The Counterweight‐Plus weight management programme achieved 46% remission of Type 2 diabetes at 1 year in the DiRECT trial. We estimated the implementation costs of the Counterweight‐Plus programme and its 1‐year cost‐effectiveness in terms of diabetes remission, compared with usual care, from the UK National Health Service (NHS) perspective. Methods: Within‐trial total costs included programme set‐up and running costs (practitioner appointment visits, low‐energy formula diet sachets and training), oral anti‐diabetes and anti‐hypertensive medications, and healthcare contacts. Total costs were calculated for aggregated resource use for each participant and 95% confidence intervals (CI) were based on 1000 non‐parametric bootstrap iterations. Results: One‐year programme costs under trial conditions were estimated at £1137 per participant (95% CI £1071, £1205). The intervention led to a significant cost‐saving of £120 (95% CI £78, £163) for the oral anti‐diabetes drugs and £14 (95% CI £7.9, £22) for anti‐hypertensive medications compared with the control. Deducting the cost‐savings of all healthcare contacts from the intervention cost resulted an incremental cost of £982 (95% CI £732, £1258). Cost per 1 year of diabetes remission was £2359 (95% CI £1668, £3250). Conclusions: Remission of Type 2 diabetes within 1‐year can be achieved at a cost below the annual cost of diabetes (including complications). Providing a reasonable proportion of remissions can be maintained over time, with multiple medical gains expected, as well as immediate social benefits, there is a case for shifting resources within diabetes care budgets to offer support for people with Type 2 diabetes to attempt remission. (Clinical Trial Registry No.: ISRCTN03267836)

European regulatory agenices should employ full time statisticians

No abstract available

Rethinking the social impacts of the arts

The paper presents a critical discussion of the current debate over the social impacts of the arts in the UK. It argues that the accepted understanding of the terms of the debate is rooted in a number of assumptions and beliefs that are rarely questioned. The paper goes on to present the interim findings of a three‐year research project, which aims to rethink the social impact of the arts, with a view to determining how these impacts might be better understood. The desirability of a historical approach is articulated, and a classification of the claims made within the Western intellectual tradition for what the arts “do” to people is presented and discussed

Fighting Cybercrime: A Review of the Irish Experience

Criminal computer data legislation in Ireland dates to 1991, however its next iteration was not until 2017. Its implementation is still in its infancy and needs an effective, consistent constitutional framework to ensure accountability and action. Irish legislation is important for monitoring 30% of EU data, but is limited in its belated modernisation. Therefore, it is important for personal, criminal, and national security defining cybercrime legislation to review current Irish legislation of technology related crimes. Statistics alone cannot interpret legislative efficacy, and therefore qualitative understanding the experiences of digital security practitioners whose professions are directed by relevant legislation could produce beneficial insights. This research analysed interviews with seventeen digital security experts about their professional experiences and opinions relating to cybercrime legislation. Primary emergent themes were identified as: Awareness and prioritisation, jurisdiction and reporting limits, technological advances and the legislative sprawl of dealing with cybercrime today. This research contributes to Irish legal understandings of cybercrime regulation and technology use today, and suggests how to address legislative developments in the future, based on the experiences of an expert security panel

Forward to the past: reinventing intelligence-led policing in Britain

Drawing on archival, secondary material and primary research, this paper examines 'Total Policing', the strategy recently adopted by London's Metropolitan Police. It situates that analysis within a critical examination of other innovative policing strategies previously employed in Britain. It argues that the prospects for Total Policing depend upon the resolution of long-standing problems such as: the inadequacy and inefficiency of local intelligence work; the paucity of evidence for the success of commanders' previous efforts to harness together the component parts of their forces in pursuit of a single mission; and, above all, a seeming inability to learn the lessons of the past. © 2013 © 2013 Taylor & Francis