Transition of pupils from Key Stage 2 to 3 deemed gifted and talented in mathematics: an initial study

In this article Geoff Tennant and Dave Harries report on the early stages of a research project looking to examine the transition from Key Stage (KS) 2 to 3 of children deemed Gifted and Talented (G&T) in mathematics. An examination of relevant literature points towards variation in definition of key terms and underlying rationale for activities. Preliminary fieldwork points towards a lack of meaningful communication between schools, with primary school teachers in particular left to themselves to decide how to work with children deemed G&T. Some pointers for action are given, along with ideas for future research and a request for colleagues interested in working with us to get in touch

High-cadence, High-resolution Spectroscopic Observations of Herbig Stars HD 98922 and V1295 Aquila

Recent observational work has indicated that mechanisms for accretion and outflow in Herbig Ae/Be star-disk systems may differ from magnetospheric accretion (MA) as it is thought to occur in T Tauri star-disk systems. In this work, we assess the temporal evolution of spectral lines probing accretion and mass loss in Herbig Ae/Be systems and test for consistency with the MA paradigm. For two Herbig Ae/Be stars, HD 98922 (B9e) and V1295 Aql (A2e), we have gathered multi-epoch (~years) and high-cadence (~minutes) high-resolution optical spectra to probe a wide range of kinematic processes. Employing a line equivalent width evolution correlation metric introduced here, we identify species co-evolving (indicative of common line origin) via novel visualization. We interferometrically constrain often problematically degenerate parameters, inclination and inner disk radius, allowing us to focus on the structure of the wind, magnetosphere, and inner gaseous disk in radiative transfer models. Over all timescales sampled, the strongest variability occurs within the blueshifted absorption components of the Balmer series lines; the strength of variability increases with the cadence of the observations. Finally, high-resolution spectra allow us to probe substructure within the Balmer series' blueshifted absorption components: we observe static, low-velocity features and time-evolving features at higher velocities. Overall, we find the observed line morphologies and variability are inconsistent with a scaled-up T Tauri MA scenario. We suggest that as magnetic field structure and strength change dramatically with increasing stellar mass from T Tauri to Herbig Ae/Be stars, so too may accretion and outflow processes.Comment: 34 pages, 52 figures, published in the Ap

Modelling circumstellar discs with 3D radiation hydrodynamics

We present results from combining a grid-based radiative transfer code with a Smoothed Particle Hydrodynamics code to produce a flexible system for modelling radiation hydrodynamics. We use a benchmark model of a circumstellar disc to determine a robust method for constructing a gridded density distribution from SPH particles. The benchmark disc is then used to determine the accuracy of the radiative transfer results. We find that the SED and the temperature distribution within the disc are sensitive to the representation of the disc inner edge, which depends critically on both the grid and SPH resolution. The code is then used to model a circumstellar disc around a T-Tauri star. As the disc adjusts towards equilibrium vertical motions in the disc are induced resulting in scale height enhancements which intercept radiation from the central star. Vertical transport of radiation enables these perturbations to influence the mid-plane temperature of the disc. The vertical motions decay over time and the disc ultimately reaches a state of simultaneous hydrostatic and radiative equilibrium.Comment: MNRAS accepted; 15 pages; 17 figures, 4 in colou

Evolving Meanings of the War for Ukraine: Winning, Losing, Fearing, Needing

The accelerating pace of change and even the near-term unpredictability of its consequences calls for more enlightened and timely analyses of the most globally disruptive events. The continuing war for Ukraine is indisputably such an event. This essay presents an academically unconventional assessment of what that war means, addressing its consequences in terms of four conditions; winning, losing, fearing and needing. Until the war, at least, stalemates, it will be, if not impossible, unwise to decide on the winners and the losers, or on the fears that were fully realized, or on what needs remain to be met. Every effort has been made to express the listed issues in ways that do not foreclose their analysis, recognizing that, for all of them, tomorrow will be different not only to 24 February but to yesterday

Isomorphisms in switching classes of graphs

We introduce notation and terminology to investigate conditions on a permutation group G sufficient to ensure that G fixes a graph in any switching class of graphs that it stabilises. We show that cyclic groups, groups of odd order groups of order ^k+2 and all stabilisers of switching classes of graphs on an odd number of vertices have this property. In Chapter 5 we give a necessary and sufficient condition for a dihedral group to have this property. In Chapter'6 we consider switching classes containing forests and graphs with a given girth g > 5. We give necessary and sufficient conditions for the stabilisers of all such switching classes to fix graphs in their classes. Finally we give a brief account of the link between strong graphs and switching, and give an example of a class of switching classes with doubly transitive stabilisers

Panel: Restoring Grocery Access: The Vinton, Ohio

The village of McArthur sits in rural Vinton County in Southeast Ohio, with approximately 1,300 residents. In 2013, McArthur’s grocery store, the only grocery store in the county, was sold to Dollar General, which does not sell fresh food. As a result, residents had to travel more than 30 minutes from McArthur to another county to get fresh produce and groceries. McArthur also has a large population of seniors and others for whom access to transportation and to grocery stores is particularly limited. Launched in March of 2016, the Healthy Food for Ohio (HFFO) program, a Healthy Food Financing Initiative (HFFI), was able to attract and support a local grocer, Campbell’s Market, restoring the county with fresh food. The Campbell’s family has been in the grocery industry for more than 85 years and opened a 12,000 square foot store, adjacent to the local high school, in the winter of 2017. Campbell’s has hired over 30 employees from the local community and accepts SNAP and WIC food assistance benefits

Control of led emission via surface plasmon interaction

In this thesis we demonstrate how the optical emission from a typical light emitting diode (LED) device can be spatially controlled via the deposition of a periodically structured gold film. A periodically structured gold film was deposited within a 20 um square aperture in the top, p-doped, contact surface of an AlGaInP/GaInP multiple quantum well edge emitting LED. We show that the far-field emission is vastly altered and is spatially controlled by the properties local to the surface plasmon. It is shown that each order of rotational symmetry produces a single emission curve in the far-field which is related directly to the coupling of photon to surface plasmon via the grating vector. We find that the origin of these strong emission curves in the far field is emission of the surface plasmon as photons. These are highly polarised and have a peak emission of 660 nm (as opposed to the peak wavelength from the standard LED device of 654 nm). The k vector for the surface plasmon propagating within the thin gold film with SiO2 islands is found to be 1.002x10 7 m"1 from experimental measurement. It is also shown that a similar gold film with a grating of 592 nm would result in normal emission. Considering the surface plasmon emission as being analogous to emission from a linear dipole antenna array, the far-field emission as a function of angle is modelled using Matlab. From comparison with real profile plots this suggests that a surface plasmon wave spans a distance of 7.5 nm which agrees approximately with the propagation length of a surface plasmon in this gold film