Catastrophic volcanism as a cause of shocked features found at the K/T boundary and in cryptoexplosion structures

The presence of quartz grains containing shock lamellae at the Cretaceous/Tertiary (K/T) boundary is viewed by many as the single most compelling evidence of meteoritic or cometary impact because there is no known endogenous mechanism for producing these features. Similarly the presence of shocked quartz, shatter cones, coesite and stishovite at cryptoexplosion structures is comonly taken as conclusive evidence of impact. However, several recent studies have cast doubt on this interpretation. It is argued that basaltic volcanism, although not normally explosive, can under exceptional circumstances produce overpressures sufficiently high to produce shock features. The exceptional circumstances include a high content of volatiles, usually CO2, and no preestablished pathway to the surface. Rapid cooling of the saturated basaltic magma can occur if it underlies a cooler more evolved magma in a chamber. Initial slow cooling and partial exsolution of the volatiles will cause the density of the basaltic magma to become less than that of the overlying magma, leading to overturning and mixing. Gas will escape the magma chamber along planar cracks once the pressure becomes sufficiently high. In the vicinity of the crack tip there is a smallscale deviatoric stress pattern which is thought to be sufficiently high to produce transient cracks along secondary axes in the quartz crystals, causing the planar features. The CO2-rich fluid inclusions which have been found along planar elements of quartz in basement rocks of the Vredefort Dome were likely to have been emplaced by such a process. If the mechanism described is capable of producing shocked features as above, it would require a reassessment of the origin of many cryptoexplosion structures as well as seriously weakening the case for an impact origin of the K/T event

A Case Against School Choice: Carson Ex Rel. O.C. v. Makin and the Future of Maine\u27s Nonsectarian Requirement

School choice advocates, such as the nonprofit libertarian law firm, The Institute for Justice, have spent decades arguing that states violate the Free Exercise Clause when they exclude private religious schools from public programs that otherwise provide public dollars to non-religious private schools. Recently, in Espinoza v. Montana Department of Revenue, the Supreme Court effectively agreed with that sentiment. After this victory, the Institute for Justice returned to the state of Maine to represent three sets of parents in a renewed effort to defeat Maine’s nonsectarian requirement in federal court. Maine’s nonsectarian requirement provides that private religious schools may not participate in Maine’s town tuitioning program, which allows students in towns that do not have public schools to receive state funding to attend a private or public school of their choice. This Note analyzes that case: Carson ex rel. O.C. v. Makin. In Carson, the First Circuit affirmed the trial court’s decision that Maine’s nonsectarian requirement does not violate the Free Exercise Clause. I posit that the reasoning the First Circuit deployed in Carson may not be durable and that if the Supreme Court were to grant the plaintiff-appellants’ petition for certiorari, the Court would likely invalidate Maine’s nonsectarian requirement. I then analyze the effect the elimination of the nonsectarian requirement would have on Maine’s public schools and how school choice opponents may wish to move forward. More specifically, I suggest that Maine and the rest of the nation should consider investing in its public schools before outsourcing public education to private entities and interest groups

Use of record-linkage to handle non-response and improve alcohol consumption estimates in health survey data: a study protocol

<p>Introduction: Reliable estimates of health-related behaviours, such as levels of alcohol consumption in the population, are required to formulate and evaluate policies. National surveys provide such data; validity depends on generalisability, but this is threatened by declining response levels. Attempts to address bias arising from non-response are typically limited to survey weights based on sociodemographic characteristics, which do not capture differential health and related behaviours within categories. This project aims to explore and address non-response bias in health surveys with a focus on alcohol consumption.</p> <p>Methods and analysis: The Scottish Health Surveys (SHeS) aim to provide estimates representative of the Scottish population living in private households. Survey data of consenting participants (92% of the achieved sample) have been record-linked to routine hospital admission (Scottish Morbidity Records (SMR)) and mortality (from National Records of Scotland (NRS)) data for surveys conducted in 1995, 1998, 2003, 2008, 2009 and 2010 (total adult sample size around 40 000), with maximum follow-up of 16 years. Also available are census information and SMR/NRS data for the general population. Comparisons of alcohol-related mortality and hospital admission rates in the linked SHeS-SMR/NRS with those in the general population will be made. Survey data will be augmented by quantification of differences to refine alcohol consumption estimates through the application of multiple imputation or inverse probability weighting. The resulting corrected estimates of population alcohol consumption will enable superior policy evaluation. An advanced weighting procedure will be developed for wider use.</p> <p>Ethics and dissemination: Ethics approval for SHeS has been given by the National Health Service (NHS) Multi-Centre Research Ethics Committee and use of linked data has been approved by the Privacy Advisory Committee to the Board of NHS National Services Scotland and Registrar General. Funding has been granted by the MRC. The outputs will include four or five public health and statistical methodological international journal and conference papers.</p&gt

Integral equations of a cohesive zone model for history-dependent materials and their numerical solution

A nonlinear history-dependent cohesive zone (CZ) model of quasi-static crack propagation in linear elastic and viscoelastic materials is presented. The viscoelasticity is described by a linear Volterra integral operator in time. The normal stress on the CZ satisfies the history-dependent yield condition, given by a nonlinear Abel-type integral operator. The crack starts propagating, breaking the CZ, when the crack tip opening reaches a prescribed critical value. A numerical algorithm for computing the evolution of the crack and CZ in time is discussed along with some numerical results

A physics-based life prediction methodology for thermal barrier coating systems

A novel mechanistic approach is proposed for the prediction of the life of thermal barrier coating (TBC) systems. The life prediction methodology is based on a criterion linked directly to the dominant failure mechanism. It relies on a statistical treatment of the TBC's morphological characteristics, non-destructive stress measurements and on a continuum mechanics framework to quantify the stresses that promote the nucleation and growth of microcracks within the TBC. The last of these accounts for the effects of TBC constituents' elasto-visco-plastic properties, the stiffening of the ceramic due to sintering and the oxidation at the interface between the thermally insulating yttria stabilized zirconia (YSZ) layer and the metallic bond coat. The mechanistic approach is used to investigate the effects on TBC life of the properties and morphology of the top YSZ coating, metallic low-pressure plasma sprayed bond coat and the thermally grown oxide. Its calibration is based on TBC damage inferred from non-destructive fluorescence measurements using piezo-spectroscopy and on the numerically predicted local TBC stresses responsible for the initiation of such damage. The potential applicability of the methodology to other types of TBC coatings and thermal loading conditions is also discussed

Science, society, and policy in the face of uncertainty: reflections on the debate around face coverings for the public during COVID-19

The Covid-19 pandemic has had enormous effects on health, wellbeing and economies worldwide. Governments have responded with rapid and sometimes radical public health interventions. As nations grapple with the question of how to regain normality without unnecessarily endangering lives or healthcare systems, some scientists have argued for policies to encourage or compel use of face coverings in community (non-clinical) settings, despite acknowledged gaps in the evidence base for the effectiveness of such a measure. This commentary has two objectives. First, in the face of strong arguments that face coverings are a commonsense intervention, with negligible downsides, that can only do good, we make the case for caution in changing policy. Many seemingly benign public health interventions have the potential to cause harm, and that harm is often socially differentiated. We present five arguments for caution in policy change. Second, we reflect on the wider implications of the increasingly overt approaches to policy advocacy taken by some scientists. Drawing from the theory of post-normal science, we argue that the science-policy interface in the case of face coverings has taken a surprisingly traditional form, falling short of interdisciplinary integration and failing to incorporate insights of the full range of relevant experts and affected stakeholders. We sketch a vision for an alternative, more mature, relationship between science and society that accepts uncertainty, embraces deliberation, and rises to the challenge of developing knowledge to improve public health

EUPHORIA: End-User Construction of Direct Manipulation User Interfaces for Distributed Applications

The Programmers\u27 Playground is a software library and run-time system for creating distributed multimedia applications from collections of reusable software moduels. This paper presents the design and implementation of EUPHORIA, Playground\u27s user interface management system. Implemented as a Playground module, EUPHORIA allows end-users to create direct manipulation graphical user interfaces (GUIs) exclusively through the use of a graphics editor. No programming is required. At run-time, attributes of the GUI state can be exposed and connected to external Playground modules, allowing the user to vosualize and directly manipulate state information in remote Playground modules. Features of EUPHORIA include real-time direct manipulation graphics, constraint-based editing and visualization, imaginary alignment objects, user-definable types, and user-definable widgets with alternative representations