Junior Recital: Grace Johnston, violin

This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Performance. Ms. Johnston studies violin with Helen Kim.https://digitalcommons.kennesaw.edu/musicprograms/1069/thumbnail.jp

Diversity and vulnerability in Prisons in the context of the Equality Act 2010: the experiences of Black, Asian, Minority Ethnic (BAME)and Foreign National Prisoners (FNPs) in a Northern Jail

This article details findings from a pilot study that was funded by the universities of Newcastle, Northumbria and Liverpool John Moores. The study was undertaken in an English Northern prison by members of the North East Regional Race Crime and Justice Research Network (NERRCJRN) and was approved by the National Offender Management Service (NOMS). The study arose out of concerns by practitioner members of the NERRCJRN that following the passing of the Equality Act (2010) there had been a dilution of focus on ‘race’ equality. The Equality Act (2010) shifted the emphasis from an Equality Duty that was focused on distinct protected characteristics of race, disability, gender to one that is all inclusive. The concern was that the positive focus on 'race' which had been growing in recent years, particularly in prisons, would be compromised. The aims of the pilot project were to explore the experiences of BAME national and Foreign National Prisoners (FNPs) in this prison (which is a Category B adult male prison) to find out how the specific needs of these prisoners are being met and to explore how the prison is responding to and managing prisoner vulnerability in relation to 'race', post the 2010 Ac

Evidence for a Triaxial Milky Way Dark Matter Halo from the Sagittarius Stellar Tidal Stream

Observations of the lengthy tidal streams produced by the destruction of the Sagittarius dwarf spheroidal (Sgr dSph) are capable of providing strong constraints on the shape of the Galactic gravitational potential. However, previous work, based on modeling different stream properties in axisymmetric Galactic models has yielded conflicting results: while the angular precession of the Sgr leading arm is most consistent with a spherical or slightly oblate halo, the radial velocities of stars in this arm are only reproduced by prolate halo models. We demonstrate that this apparent paradox can be resolved by instead adopting a triaxial potential. Our new Galactic halo model, which simultaneously fits all well-established phase space constraints from the Sgr stream, provides the first conclusive evidence for, and tentative measurement of, triaxiality in an individual dark matter halo. The Milky Way halo within ~ 60 kpc is best characterized by a minor/major axis ratio of the isovelocity contours c/a ~ 0.67, intermediate/major axis ratio b/a ~ 0.83, and triaxiality parameter T ~ 0.56. In this model, the minor axis of the dark halo is coincident with the Galactic X axis connecting the Sun and the Galactic Center to within ~ 15 degrees, while the major axis also lies in the Galactic plane, approximately along the Galactic Y axis.Comment: Accepted for publication in ApJ Letters. 3 figure

Senior Recital: Katherine Johnston, clarinet

This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Music Education. Ms. Johnston studies clarinet with John Warren.https://digitalcommons.kennesaw.edu/musicprograms/1295/thumbnail.jp

Senior Recital: Grace Johnston, violin

This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Performance. Ms. Johnston studies violin with Helen Kim.https://digitalcommons.kennesaw.edu/musicprograms/1947/thumbnail.jp

Variability of Blue Supergiants in the LMC with TESS

The blue supergiant problem, namely the overabundance of blue supergiants (BSGs) inconsistent with classical stellar evolution theory, remains an open question in stellar astrophysics. Several theoretical explanations have been proposed, which may be tested by their predictions for the characteristic time variability. In this work, we analyze the light curves of a sample of 20 BSGs obtained from the Transiting Exoplanet Survey Satellite (TESS) mission. We report a characteristic signal in the low-frequency ($f\lesssim2\,\mathrm{d}^{-1}$) range for all our targets. The power spectra has a peak frequency at $\sim0.2\,\mathrm{d}^{-1}$, and we are able to fit it by a modified Lorentzian profile. The signal itself shows strong stochasticity across different TESS sectors, suggesting its driving mechanism happens on short ($\lesssim\mathrm{months}$) timescales. Our signals resemble those obtained for a limited sample of hotter OB stars and yellow supergiants, suggesting their possible common origins. We discuss three possible physical explanations: stellar winds launched by rotation, convection motions that reach the stellar surface, and waves from the deep stellar interior. The peak frequency of the signal favors processes related to convection caused by the iron opacity peak, and the shape of the spectra might be explained by the propagation of high-order, damped gravity waves. We discuss the uncertainties and limitations of all these scenarios.Comment: submitted to ApJ, comments welcom

Analysis of galactic tides and stars on CDM microhalos

A special purpose N-body simulation has been built to understand the tidal heating of the smallest dark matter substructures (10^{-6}\msun and 0.01pc) from the grainy potential of the Milky Way due to individual stars in the disk and the bulge. To test the method we first run simulations of single encounters of microhalos with an isolated star, and compare with analytical predictions of the dark particle bound fraction as a function of impact parameter. We then follow the orbits of a set of microhalos in a realistic flattened Milky Way potential. We concentrate on (detectable) microhalos passing near the Sun with a range of pericenter and apocenter. Stellar perturbers near the orbital path of a microhalo would exert stochachstic impulses, which we apply in a Monte Carlo fashion according to the Besancon model for the distribution of stars of different masses and ages in our Galaxy. Also incorporated are the usual pericenter tidal heating and disk-shocking heating. We give a detailed diagnosis of typical microhalos and find microhalos with internal tangential anisotropy are slightly more robust than the ones with radial anisotropy. In addition, the dark particles generally go through of a random walk in velocity space and diffuse out of the microhalos. We show that the typical destruction time scales are strongly correlated with the stellar density averaged along a microhalo's orbit over the age of the stellar disk. We also present the morphology of a microhalo at several epochs which may hold the key to dark matter detections.Comment: 15 pages, 12 figure

Quantifying abundance and distribution of native and invasive oysters in an urbanised estuary

© 2016 The Author(s). Journal compilation, 2016 REABIC. Human activities have modified the chemical, physical and biological attributes of many of the world’s estuaries. Natural foreshores have been replaced by artificial habitats and non-indigenous species have been introduced by shipping, aquaculture, and as ornamental pets. In south east Australia, the native Sydney rock oyster Saccostrea glomerata is threatened by pollution, disease and competition from the invasive Pacific oyster Crassostrea gigas. This study assessed the abundance (as number m-2), size, and distribution of both invasive and native oyster species at 32 sites in the heavily urbanised Port Jackson Estuary, Australia. We tested the hypotheses that there would be: (1) a difference in the proportion of C. gigas and S. glomerata among locations; (2) a greater proportion of C. gigas on artificial compared to natural substrates; (3) a greater numbers of all oysters, with differing size characteristics, on artificial compared to natural substrates; and (4) that the abundance and size of all oysters would vary among locations along an environmental gradient. Environmental variables included distance from the estuary mouth and salinity. We found the abundance and size of all oysters differed among locations; smaller oysters occurred at greater abundances near the mouth of the estuary. Abundance was also higher on artificial, than on natural substrate. Habitat type, however, had no effect on which species of oyster was present. In contrast, distance from the estuary mouth strongly influenced the relative proportion of the two species. The invasive C. gigas comprised 16% of the oysters sampled, and up to 85% at some of the upper estuary sites. As predicted, C. gigas was more abundant at locations in the bay ends and upper channel of the estuary; it was also larger in size than the native S. glomerata. This is the first assessment of oyster distribution in Port Jackson and provides a solid base for monitoring changes in the estuarine distribution of a globally invasive pest

Using microtechnology to quantify torso angle during match-play in field hockey

Warman, GE, Cole, MH, Johnston, RD, Chalkley, D, and Pepping, GJ. Using microtechnology to quantify torso angle during match-play in field hockey. J Strength Cond Res 33(10): 2648–2654, 2019—Field hockey is played in a dynamic environment placing specific postural demands on athletes. Little research has been devoted to understanding the nature of a player's torso postures in field hockey match-play and its relationship with the perceptuomotor demands of the sport. We used commercially available microtechnology worn by 16 athletes during a 6-match national tournament to quantify torso flexion/extension angles. Orientation was derived using the inertial and magnetic sensors housed within global positioning system devices, assessing torso angle in the sagittal plane from 91 individual match files. The main independent variable was playing position, whereas the dependent variable was torso flexion/extension, presented as a percentage of playing time spent in 15 × 10° torso postural bands ranging from ≥40° extension to ≥90° flexion. It was shown that athletes spent 89.26% of their playing time in various torso postures, ranging from 20 to 90° of flexion. Defenders spent more time than midfielders (p = 0.004, effect size [ES] = 0.43) and strikers (p = 0.004; ES = 0.44) in the posture band of 10–20° torso flexion, whereas midfielders spent more time between 20 and 30° of torso flexion (p = 0.05; ES = 0.32) than strikers. Conversely, strikers spent more time between 30 and 40° of flexion than defenders (p < 0.001; ES = 0.74). These results reflect the sport-specific and role-specific torso angles adopted by field hockey athletes during match-play. Coaching staff can use these data to gain insight into the postural demands of their sport and inform the preparation of athletes for the perception-action demands of competition