Vaterite Dissolution: Mechanism and Kinetics

The dissolution of porous spherulitic, vaterite particles in aqueous solution is investigated via microscopic monitoring of their size as a function of time. The latter is shown to provide a clear, generic distinction between dissolution controlled either by the rate of a surface-controlled reaction or via dissolution under conditions where the concentration of calcium and carbonate ions is pinned locally by the solubility product of vaterite followed by diffusion away from the dissolving interface into the bulk solution. Dissolution under “thermodynamic control” is shown to be the case for vaterite particles, allowing a value of the solubility product to be determined in the light of the known solution phase equilibria, including the ion pairs CaCO3, CaOH+, and CaHCO3 +

Manipulation and trapping of sub-micron bioparticles using dielectrophoresis

A non-uniform alternating electric field induces motion in polarisable particles called dielectrophoresis. The effect is governed by the relative magnitudes of the dielectric properties of the medium and the particles. The technology has been used to manipulate particles for biotechnological applications, including purification, fractionation and concentration of cells and micro-organisms. However, the lower size limit for the dielectrophoretic manipulation of particles was believed to be about 1 ?m, but recent work has proved otherwise. The dielectrophoretic movement and properties of latex beads and a simple rod-shaped virus, tobacco mosaic virus (TMV), have been measured using microfabricated electrode structures. Measurements have been made over a range of suspending medium conductivities, applied frequencies and electric field strengths. It is shown that under appropriate conditions both latex beads and tobacco mosaic virus particles can be selectively attracted to regions of high electric field strength located at the tips of microfabricated electrode structures. The ability to selectively trap and separate bio-particles has many potential applications in the area of biotechnology

Fatal myocardial microabscesses caused by methicillin-resistant Staphylococcus aureus in a burn patient

AbstractBacteremia- or sepsis-associated myocardial abscess is often an incidental postmortem diagnosis in patients who die of overwhelming septicemia. Myocardial abscess is more rarely the immediate cause of death as a consequence of abscess rupture or the cause of arrhythmia. We report a 66-year-old female who succumbed to sudden cardiac death with a hemodynamically stable methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, while in recovery after an accidental thermal burn. Autopsy revealed extensive myocardial abscesses and an abscess in the pineal gland. Myocardial microabscesses should be considered a rare cause of sudden cardiac death in patients with hemodynamically stable MRSA bacteremia

A wide-spectrum language for verification of programs on weak memory models

Modern processors deploy a variety of weak memory models, which for efficiency reasons may (appear to) execute instructions in an order different to that specified by the program text. The consequences of instruction reordering can be complex and subtle, and can impact on ensuring correctness. Previous work on the semantics of weak memory models has focussed on the behaviour of assembler-level programs. In this paper we utilise that work to extract some general principles underlying instruction reordering, and apply those principles to a wide-spectrum language encompassing abstract data types as well as low-level assembler code. The goal is to support reasoning about implementations of data structures for modern processors with respect to an abstract specification. Specifically, we define an operational semantics, from which we derive some properties of program refinement, and encode the semantics in the rewriting engine Maude as a model-checking tool. The tool is used to validate the semantics against the behaviour of a set of litmus tests (small assembler programs) run on hardware, and also to model check implementations of data structures from the literature against their abstract specifications

‘The Millennial Generation Reading the Past through Literature’ - The Past Matters Festival, Montsalvat, 27 July 2013

The Past Matters Festival, Montsalvat, 27 July 2013Forum Participants: James Burgmann-Milner, Fiannuala Morgan, John Morrissey, Jon Ricketson, Kate Leah Rendel

What Type of Collegiate Pilot is Likely to Experience Imposter Phenomenon?

Background: Imposter Syndrome (IS), also called Imposter Phenomenon (IP), has been studied in a variety of paradigms over the past few decades. However, IP is not a well-researched concept in the field of aviation, and no studies that we know of have examined this phenomenon with student pilots. Method: Two hundred and forty-one student pilots were interviewed from two southeastern universities with flight schools. Participants were asked a series of questions about demographics, flight training, personality measures, self-efficacy, self-handicapping, and perceived organizational support. In addition, they responded to the Clance IP scale. Results: A regression equation was created from the first dataset and tested for model fit with a second dataset. Four factors were found to be significant, including measures of self-handicapping, measures of self-efficacy, income, and the type of flight school, accounting for approximately 40% of the variance in the data. Model fit was strong, providing future researchers with a predictive model of IP for student pilots. Conclusion: These findings show that IP is prevalent in student pilots and correlates with self-handicapping. This is a concern that should be addressed in aviation programs

Limits of Earthquake Early Warning Accuracy and Best Alerting Strategy

We explore how accurate earthquake early warning (EEW) can be, given our limited ability to forecast expected shaking even if the earthquake source is known. Because of the strong variability of ground motion metrics, such as peak ground acceleration (PGA) and peak ground velocity (PGV), we find that correct alerts (i.e., alerts that accurately estimate the ground motion will be above a predetermined damage threshold) are not expected to be the most common EEW outcome even when the earthquake magnitude and location are accurately determined. Infrequently, ground motion variability results in a user receiving a false alert because the ground motion turned out to be significantly smaller than the system expected. More commonly, users will experience missed alerts when the system does not issue an alert but the user experiences potentially damaging shaking. Despite these inherit limitations, EEW can significantly mitigate earthquake losses for false-alert-tolerant users who choose to receive alerts for expected ground motions much smaller than the level that could cause damage. Although this results in many false alerts (unnecessary alerts for earthquakes that do not produce damaging ground shaking), it minimizes the number of missed alerts and produces overall optimal performance

Protecting Migration Corridors: Challenges and Optimism for Mongolian Saiga

Hunting pressure and habitat loss place the endangered saiga, a type of antelope that was once abundant in central Asia, at high risk of extinction, and make the protection of the migratory routes of Mongolian populations even more critical for conserving the species