Field Dependent Superfluid Density in the Optimally Doped SmFeAsO_(1-x)F_y Superconductor

The magnetic field dependence of the in-plane magnetic penetration depth for optimally doped SmFeAsO_(1-x)F_y was investigated by combining torque magnetometry, SQUID magnetometry, and muon-spin rotation. The results obtained from these techniques show all a pronounced decrease of the superfluid density as the field is increased up to 1.4 T. This behavior is analysed within a two-band model with self-consistently derived coupled gaps, where the superfluid density related to the larger gap is field independent and the superfluid density related to the smaller gap is strongly suppressed with increasing field.Comment: 7 pages, 5 figure

The polarizability model for ferroelectricity in perovskite oxides

This article reviews the polarizability model and its applications to ferroelectric perovskite oxides. The motivation for the introduction of the model is discussed and nonlinear oxygen ion polarizability effects and their lattice dynamical implementation outlined. While a large part of this work is dedicated to results obtained within the self-consistent-phonon approximation (SPA), also nonlinear solutions of the model are handled which are of interest to the physics of relaxor ferroelectrics, domain wall motions, incommensurate phase transitions. The main emphasis is to compare the results of the model with experimental data and to predict novel phenomena.Comment: 55 pages, 35 figure

Promoting the achievement of looked after children and young people across the Central South Consortium in Wales

As of March 2017, there were 5,955 children and young people in care in Wales. Across the Central South Consortium (Bridgend, Cardiff, Merthyr Tydfil, Rhondda Cynonn Taf and Vale of Glamorgan) there were 2,170 children and young people looked after. The majority of these children are in care as a result of birth families being unable to provide a level of care that meets their emotional and well-being needs. Children and young people who are in or have experienced care remain one of the lowest performing groups in terms of educational outcomes. In 2016, eleven per cent of young people in Wales achieved A* to C grade at GCSE. Care leavers can experience poorer employment and health outcomes after leaving school compared to their peers; for example, 45% of young people who were looked after were not engaged in education, training or employment (NEET) or not in touch with their local authority on their 19th birthday in 2015. This compares with around 4.9% of all other children who leave school at the end of Year 13. However, the education and achievement of children and young people in care is currently the focus of renewed policy, research and practice attention across Wales. The Social Services and Wellbeing (Wales) Act 2014 provides the legal framework for improving the well-being of people who need care and support. A national strategic approach to improving outcomes for children looked after is underway with a focus on promoting and improving collaborative working across agencies, identifying and sharing good practice and making improvements where they are needed. The purpose of this report is to share practice in selected in Central South Consortium (CSC) schools that is contributing to improved outcomes and school experiences for children and young people in care

Accessory Mineral Eu Anomalies in Suprasolidus Rocks: Beyond Feldspar

Accessory mineral Eu anomalies (Eu/Eu*) are routinely measured to infer changes in the amount of feldspar over time, allowing accessory mineral U‐Pb dates to be linked to the progressive crystallization of igneous and metamorphic rocks and, by extension, geodynamic processes. However, changes in Eu/Eu* can reflect any process that changes the relative availability of Eu2+ and Eu3+. We constructed partitioning budgets for Sm, Eu2+, Eu3+, and Gd in suprasolidus metasedimentary rocks to investigate processes that can influence accessory mineral Eu anomalies. We modeled three scenarios: (1) closed‐system, equilibrium crystallization; (2) fractionation of Eu by feldspar growth during melt crystallization; and (3) removal of Eu by melt extraction. In the closed‐system equilibrium model, accessory mineral Eu/Eu* changes as a function of fO2 and monazite stability; Eu/Eu* changes up to 0.3 over a pressure‐temperature range of 4–12 kbar and 700–950°C. Fractionation of Eu by feldspar growth is modeled to decrease accessory mineral Eu/Eu* by ~0.05–0.15 per 10 wt% feldspar crystallized. Melt extraction has a smaller effect; removal of 10% melt decreases accessory mineral Eu/Eu* in the residue by ≤0.05. Although these models demonstrate that fractionation of Eu by feldspar growth can be a dominant control on a rocks u budget, they also show that the common interpretation that Eu/Eu* only records feldspar growth and breakdown is an oversimplification that could lead to incorrect interpretation about the duration and rates of tectonic processes. Consideration of other processes that influence Eu anomalies will allow for a broader range of geological processes to be investigated by petrochronology.Plain Language SummaryMetamorphic rocks—rocks in which new minerals grew in response to increase in pressure and temperature related to deep burial or subduction—and igneous rocks—rocks that formed as magmas cool and crystallize—provide a direct record of how Earth’s continents have moved and changed through time. To read this record, geologists need to be able to measure the ages of metamorphism and magmatism: When did it happen? How long did it last? How does it relate to other rocks around the world? A common approach to addressing these questions is using U‐Pb dating of the minerals zircon, monazite, and apatite. The elements these minerals incorporate are indicative of how hot and how deep in the Earth they were when they grew. In this study we explore how geologists can use the concentrations of the element Europium (Eu) in these minerals to provide new insights into the geological meaning of U‐Pb dates, leading to more robust interpretations of Earth’s plate tectonic history.Key PointsEu anomalies in suprasolidus rocks record any process that changes the relative availability of Eu2+ and Eu3+, not just feldspar growthDisequilibrium is required for feldspar growth to strongly influence accessory mineral Eu anomaliesComparing accessory mineral Eu anomalies and Sr concentrations leads to more robust interpretation than evaluating Eu anomalies alonePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156481/1/ggge22268_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156481/3/ggge22268.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156481/2/ggge22268-sup-0001-2020GC009052-Text_SI-S01.pd

Marginal and Parametric Analysis of the Central Optimal Solution

In this paper we investigate the sensitivity analysis of the parameterized central path. First, a complete marginal analysis of the central optimal solution is developed. This analysis explains the differential properties of the central optimal solution with respect to both the cost coefficients and the right-hand side components. We also show that the marginal derivatives are uniformly bounded. Second, we present three conditions for which the parameterized central path converges. Two of these results allow the difficult situation of simultaneous perturbations in the cost coefficients and right-hand side levels

Adjusting bone mass for differences in projected bone area and other confounding variables: an allometric perspective.

The traditional method of assessing bone mineral density (BMD; given by bone mineral content [BMC] divided by projected bone area [Ap], BMD = BMC/Ap) has come under strong criticism by various authors. Their criticism being that the projected bone "area" (Ap) will systematically underestimate the skeletal bone "volume" of taller subjects. To reduce the confounding effects of bone size, an alternative ratio has been proposed called bone mineral apparent density [BMAD = BMC/(Ap)3/2]. However, bone size is not the only confounding variable associated with BMC. Others include age, sex, body size, and maturation. To assess the dimensional relationship between BMC and projected bone area, independent of other confounding variables, we proposed and fitted a proportional allometric model to the BMC data of the L2-L4 vertebrae from a previously published study. The projected bone area exponents were greater than unity for both boys (1.43) and girls (1.02), but only the boy's fitted exponent was not different from that predicted by geometric similarity (1.5). Based on these exponents, it is not clear whether bone mass acquisition increases in proportion to the projected bone area (Ap) or an estimate of projected bone volume (Ap)3/2. However, by adopting the proposed methods, the analysis will automatically adjust BMC for differences in projected bone size and other confounding variables for the particular population being studied. Hence, the necessity to speculate as to the theoretical value of the exponent of Ap, although interesting, becomes redundant