Magnetic eddy viscosity of mean shear flows in two-dimensional magnetohydrodynamics

Magnetic induction in magnetohydrodynamic fluids at magnetic Reynolds number (Rm) less than~1 has long been known to cause magnetic drag. Here, we show that when $\mathrm{Rm} \gg 1$ and the fluid is in a hydrodynamic-dominated regime in which the magnetic energy is much smaller than the kinetic energy, induction due to a mean shear flow leads to a magnetic eddy viscosity. The magnetic viscosity is derived from simple physical arguments, where a coherent response due to shear flow builds up in the magnetic field until decorrelated by turbulent motion. The dynamic viscosity coefficient is approximately $(B_p^2/2\mu_0) \tau_{\rm corr}$, the poloidal magnetic energy density multiplied by the correlation time. We confirm the magnetic eddy viscosity through numerical simulations of two-dimensional incompressible magnetohydrodynamics. We also consider the three-dimensional case, and in cylindrical or spherical geometry, theoretical considerations similarly point to a nonzero viscosity whenever there is differential rotation. Hence, these results serve as a dynamical generalization of Ferraro's law of isorotation. The magnetic eddy viscosity leads to transport of angular momentum and may be of importance to zonal flows in astrophysical domains such as the interior of some gas giants.Comment: 16 pages, 8 figure

No More Mind Games: Content Analysis of In-Game Commentary of the National Football League’s Concussion Problem

American (gridiron) football played at the professional level in the National Football League (NFL) is an inherently physical spectator sport, in which players frequently engage in significant contact to the head and upper body. Until recently, the long-term health consequences associated with on the field head trauma were not fully disclosed to players or the public, potentially misrepresenting the dangers involved in gameplay. Crucial to the dissemination of this information to the public are in-game televised commentators of NFL games, regarded as the primary conduits for mediating in-game narratives to the viewing audience. Using a social constructionist theoretical lens, this study aimed at identifying how Game Commentators represented in-game head trauma and concussions during NFL games for viewer consumption, through a content analysis of 102 randomly sampled regular season games, over the course of six seasons (2009-2014). Specifically, this research questioned the frequency and prevalence of significant contact, commentator representations of significant player contact, commentator representations of the players involved in significant contact and commentator communication of the severity of health hazards and consequences associated with significant contact. Observed during the content analysis were 226 individual incidents of significant contact. Findings indicate that commentator representations of significant contact did not appropriately convey the potential health consequences associated with head trauma and concussions to the viewing audience. Instead, incidents of significant contact were constructed by commentators as glorified instances of violence, physicality and masculinity- largely devoid and diffusive of the severity of health consequences associated with head injuries and concussions

Removing batch effects for prediction problems with frozen surrogate variable analysis

Batch effects are responsible for the failure of promising genomic prognos- tic signatures, major ambiguities in published genomic results, and retractions of widely-publicized findings. Batch effect corrections have been developed to re- move these artifacts, but they are designed to be used in population studies. But genomic technologies are beginning to be used in clinical applications where sam- ples are analyzed one at a time for diagnostic, prognostic, and predictive applica- tions. There are currently no batch correction methods that have been developed specifically for prediction. In this paper, we propose an new method called frozen surrogate variable analysis (fSVA) that borrows strength from a training set for individual sample batch correction. We show that fSVA improves prediction ac- curacy in simulations and in public genomic studies. fSVA is available as part of the sva Bioconductor package

Ministry Strategy for Retaining Youth and Young Adults in the Australian Union Conference

Problem In the Seventh-day Adventist Church of Australia (known as the Australian Union Conference) there is a significant loss of membership continuance by youth and young adults that falls into the category of the so-called millennials. Church attendance and membership loss of millennials is a problem in the Australian Union Conference. Method After consulting Scripture and current literature on families and family values, this researcher developed a quantitative and qualitative survey for Seventh-day Adventist (SDA) Australian Millennials. It used a professional survey program that guaranteed the anonymity of each person. Embedded within the 18-question survey was space for personal responses. It was widely advertised using all the communication pathways available to the Youth Departments of the Union Conference and the nine Local Conferences. There were 424 survey responses, with some 30,000 words of personal understanding and attitudes. The data collected from Adventist millennials in Australia completed the strategy to implement change within the Seventh-day Adventist Church of the Australian Union Conference. After the discovery of the six essential strategies outlined in the book Growing Young there was a process where these strategies were adapted to fit the Australian Adventist church and rolled out into five of the nine conferences with more than 90 churches participating. This adaption was called Growing Together. Results This research drew attention to personal, demographic, social, psychological, and spiritual dimensions of the youth and young adults. The number and quality of responses provided valuable input for the youth department. In particular, the youth and young adults were very positive about the fact that they were being listened to. They wanted to be accepted for who they are, and they also wanted to participate actively within the functioning of the church. They desired much more than that of being passive observers. The data collected from the survey aligned with every one of the six essential strategies outlined in Growing Young. This included: keychain leadership, fueling a warm community, prioritizing young people everywhere, taking Jesus’ message seriously, empathizing with today\u27s young people, and being the best neighbor. Growing Together, as noted above, was ready in late 2019 to be rolled out to all nine Australian conferences the next year. The impact of COVID-19 in 2020 and beyond transformed the strategy into a smaller version and instead rolled out to five of the nine conferences with more than 90 churches participating from the year 2020. COVID-19 had many negative impacts on the church with continuous lockdowns and the inability for churches to meet. As restrictions lifted churches came back together and many are now continuing with the implementation of the Growing Together strategies. It is exciting to see church culture moving in a positive direction with many good news stories coming to light from stronger mentor/mentee relationships, greater intergenerational connections, and much stronger family networks being developed. It must be acknowledged that the rolling out of these six essential strategies is moving towards a positive change of church culture within the Australian church. It must also be noted that the implementation of these strategies are a slow cooker approach. While changes made from 2020 onwards are making inroads, and the preliminary changes will be reported in later chapters, the real test of this change will be five to seven years into the future which is outside the scope of this study. Conclusions This process of working through the issues and gaining the information has provided the youth and young adults themselves, along with the Union Conference and the Local Conferences, a much clearer picture of what is happening in the Australian Union Conference. The data collected has helped to clarify where constructive change is needed, and what issues have been negative in outcome. With the rollout of Growing Together well underway, the Australian Adventist church is already seeing positive changes in church culture and the way that church is done. The intentional emphasis on mentor/mentee relationships, stronger intergenerational relationships and stronger families is having a positive impact on the Australian Adventist church. Change happens slowly and the goal of the implementation of these strategies is to see a stronger engagement of church life with millennials and the following generations

Rules Without...: Some Critical Reflections on the Federal Corporate Sentencing Guidelines

Essentially, what is wrong with the Guidelines is that they are rules without -without rationality, without authority, without constitutionality. What went wrong is an old pattern of deficiency in government that seems to recur in endless variation: power without adequate discipline becomes tyranny. The possible solutions are equally simple: reinforce the discipline, or withdraw the power. The former tends to be a risky strategy for a free people, for most disciplinary procedures can be circumvented. Therefore, perhaps it is time to reexamine whether the power should be granted at all, that is, whether the Sentencing Commission should be put out of the business of corporate sentencing