Phase field approach to heterogeneous crystal nucleation in alloys

We extend the phase field model of heterogeneous crystal nucleation developed recently [L. Gránásy, T. Pusztai, D. Saylor, and J. A. Warren, Phys. Rev. Lett. 98, 035703 (2007)] to binary alloys. Three approaches are considered to incorporate foreign walls of tunable wetting properties into phase field simulations: a continuum realization of the classical spherical cap model (called Model A herein), a non-classical approach (Model B) that leads to ordering of the liquid at the wall, and to the appearance of a surface spinodal, and a non-classical model (Model C) that allows for the appearance of local states at the wall that are accessible in the bulk phases only via thermal fluctuations. We illustrate the potential of the presented phase field methods for describing complex polycrystalline solidification morphologies including the shish-kebab structure, columnar to equiaxed transition, and front-particle interaction in binary alloys

Cycling and Health Innovative Pilot Projects (Executive summary)

The Cycling and Health Innovative Pilot Project (CHIPPS) provided cycle training for adults in Nottingham and Northamptonshire from 2007 to 2010. The Primary Care Trusts in each area have delivered these projects in collaboration with partners. In Nottingham collaboration with Ridewise delivered the Cycling for Health Project that aimed to involve people from deprived communities and employees of the Primary Care Trust; in Northamptonshire the Easy Rider project delivered via Age UK was also aimed at those living in deprived areas and middle-aged people. Throughout the three years the initiative was evaluated by the Carnegie Research Institute of Leeds Metropolitan University. Those taking part completed questionnaires at the outset, at the end of their training, three months later and finally after a year. In addition, a mix of one-to-one interviews and focus groups were conducted with policy makers, those delivering the projects and participants (including those who dropped out)

Assessing Descriptive Substance in Free-Text Collection-Level Metadata

Collection-level metadata has the potential to provide important information about the features and purpose of individual collections. This paper reports on a content analysis of collection records in an aggregation of cultural heritage collections. The findings show that the free-text Description field often provides more accurate and complete representation of subjects and object types than the specified fields. Properties such as importance, uniqueness, comprehensiveness, provenance, and creator are articulated, as well as other vital contextual information about the intentions of a collector and the value of a collection, as a whole, for scholarly users. The results demonstrate that the semantically rich free-text Description field is essential to understanding the context of collections in large aggregations and can serve as a source of data for enhancing and customizing controlled vocabulariesIMLS NLG Research and Demonstration grant LG-06-07-0020-07published or submitted for publicationis peer reviewe

Sequential Symbolic Regression with Genetic Programming

This chapter describes the Sequential Symbolic Regression (SSR) method, a new strategy for function approximation in symbolic regression. The SSR method is inspired by the sequential covering strategy from machine learning, but instead of sequentially reducing the size of the problem being solved, it sequentially transforms the original problem into potentially simpler problems. This transformation is performed according to the semantic distances between the desired and obtained outputs and a geometric semantic operator. The rationale behind SSR is that, after generating a suboptimal function f via symbolic regression, the output errors can be approximated by another function in a subsequent iteration. The method was tested in eight polynomial functions, and compared with canonical genetic programming (GP) and geometric semantic genetic programming (SGP). Results showed that SSR significantly outperforms SGP and presents no statistical difference to GP. More importantly, they show the potential of the proposed strategy: an effective way of applying geometric semantic operators to combine different (partial) solutions, avoiding the exponential growth problem arising from the use of these operators

Expected-value bias in routine third-trimester growth scans.

OBJECTIVES: Operators performing fetal growth scans are usually aware of the gestational age of the pregnancy, which may lead to expected-value bias when performing biometric measurements. We aimed to evaluate the incidence of expected-value bias in routine fetal growth scans and assess its impact on standard biometric measurements. METHODS: We collected prospectively full-length video recordings of routine ultrasound growth scans coupled with operator eye tracking. Expected value was defined as the gestational age at the time of the scan, based on the estimated due date that was established at the dating scan. Expected-value bias was defined as occurring when the operator looked at the measurement box on the screen during the process of caliper adjustment before saving a measurement. We studied the three standard biometric planes on which measurements of head circumference (HC), abdominal circumference (AC) and femur length (FL) are obtained. We evaluated the incidence of expected-value bias and quantified the impact of biased measurements. RESULTS: We analyzed 272 third-trimester growth scans, performed by 16 operators, during which a total of 1409 measurements (354 HC, 703 AC and 352 FL; including repeat measurements) were obtained. Expected-value bias occurred in 91.4% of the saved standard biometric plane measurements (85.0% for HC, 92.9% for AC and 94.9% for FL). The operators were more likely to adjust the measurements towards the expected value than away from it (47.7% vs 19.7% of measurements; P < 0.001). On average, measurements were corrected by 2.3 ± 5.6, 2.4 ± 10.4 and 3.2 ± 10.4 days of gestation towards the expected gestational age for the HC, AC, and FL measurements, respectively. Additionally, we noted a statistically significant reduction in measurement variance once the operator was biased (P = 0.026). Comparing the lowest and highest possible estimated fetal weight (using the smallest and largest biased HC, AC and FL measurements), we noted that the discordance, in percentage terms, was 10.1% ± 6.5%, and that in 17% (95% CI, 12-21%) of the scans, the fetus could be considered as small-for-gestational age or appropriate-for-gestational age if using the smallest or largest possible measurements, respectively. Similarly, in 13% (95% CI, 9-16%) of scans, the fetus could be considered as large-for-gestational age or appropriate-for-gestational age if using the largest or smallest possible measurements, respectively. CONCLUSIONS: During routine third-trimester growth scans, expected-value bias frequently occurs and significantly changes standard biometric measurements obtained. © 2019 the Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology

Phase Mixing of Alfvén Waves Near a 2D Magnetic Null Point

The propagation of linear Alfvén wave pulses in an inhomogeneous plasma near a 2D coronal null point is investigated. When a uniform plasma density is considered, it is seen that an initially planar Alfvén wavefront remains planar, despite the varying equilibrium Alfvén speed, and that all the wave collects at the separatrices. Thus, in the non-ideal case, these Alfvénic disturbances preferentially dissipate their energy at these locations. For a non-uniform equilibrium density, it is found that the Alfvén wavefront is significantly distorted away from the initially planar geometry, inviting the possibility of dissipation due to phase mixing. Despite this however, we conclude that for the Alfvén wave, current density accumulation and preferential heating still primarily occur at the separatrices, even when an extremely non-uniform density profile is considered

de Branges-Rovnyak spaces: basics and theory

For $S$ a contractive analytic operator-valued function on the unit disk ${\mathbb D}$, de Branges and Rovnyak associate a Hilbert space of analytic functions ${\mathcal H}(S)$ and related extension space ${\mathcal D(S)}$ consisting of pairs of analytic functions on the unit disk ${\mathbb D}$. This survey describes three equivalent formulations (the original geometric de Branges-Rovnyak definition, the Toeplitz operator characterization, and the characterization as a reproducing kernel Hilbert space) of the de Branges-Rovnyak space ${\mathcal H}(S)$, as well as its role as the underlying Hilbert space for the modeling of completely non-isometric Hilbert-space contraction operators. Also examined is the extension of these ideas to handle the modeling of the more general class of completely nonunitary contraction operators, where the more general two-component de Branges-Rovnyak model space ${\mathcal D}(S)$ and associated overlapping spaces play key roles. Connections with other function theory problems and applications are also discussed. More recent applications to a variety of subsequent applications are given in a companion survey article

Liver failure occurring as a component of exertional heatstroke.

An unusual case of an exertional heatstroke in a healthy 25-year-old man is presented. Initially, the patient was deeply comatose and developed severe rhabdomyolysis and massive hepatic necrosis. Subsequently, he received a liver transplant with remarkable improvement in his mental status, although the rhabdomyolysis continued. The patient died 41 days after the transplant due to a complicating infection. Providing that infections can be effectively controlled, liver transplants might be a promising therapeutic alternative for the few patients who survive the initial neurological consequences of this unusual event

The flip-graph of the 4-dimensional cube is connected

Flip-graph connectedness is established here for the vertex set of the 4-dimensional cube. It is found as a consequence that this vertex set has 92 487 256 triangulations, partitioned into 247 451 symmetry classes.Comment: 20 pages, 3 figures, revised proofs and notation

Evidence to improve maternal and newborn health in Ethiopia, North East Nigeria and Uttar Pradesh, India

IDEAS aims to improve the health and survival of mothers and babies through generating evidence to inform policy and practice. IDEAS uses measurement, learning and evaluation to find out what works, why and how in maternal and newborn health. IDEAS is funded between 2010 and 2015 by a grant from the Bill & Melinda Gates Foundation to the London School of Hygiene & Tropical Medicine. One research question is"Do enhanced interactions lead to increased coverage of interventions?