The formation of high-field magnetic white dwarfs from common envelopes

The origin of highly-magnetized white dwarfs has remained a mystery since their initial discovery. Recent observations indicate that the formation of high-field magnetic white dwarfs is intimately related to strong binary interactions during post-main-sequence phases of stellar evolution. If a low-mass companion, such as a planet, brown dwarf, or low-mass star is engulfed by a post-main-sequence giant, the hydrodynamic drag in the envelope of the giant leads to a reduction of the companion's orbit. Sufficiently low-mass companions in-spiral until they are shredded by the strong gravitational tides near the white dwarf core. Subsequent formation of a super-Eddington accretion disk from the disrupted companion inside a common envelope can dramatically amplify magnetic fields via a dynamo. Here, we show that these disk-generated fields are sufficiently strong to explain the observed range of magnetic field strengths for isolated, high-field magnetic white dwarfs. A higher-mass binary analogue may also contribute to the origin of magnetar fields.Comment: Accepted to Proceedings of the National Academy of Sciences. Under PNAS embargo until time of publicatio

Subculture theory: an historical and contemporary assessment of the concept for understanding deviance

Subcultures attract attention in culture, society, and the media because they have been theorized as not merely distinct from, but aSubcultures attract attention in culture, society, and the media because they have been theorized as not merely distinct from, but also in opposition to, the dominant culture. In the United States and the United Kingdom the concept of subculture has been a major explanatory tool for sociology and criminology to understand deviant behavior. For nearly a hundred years the concept has been at the center of academic struggle for superiority between rival paradigmatic approaches, which have employed different theoretical explanations. In this article I critically assess the origins and politics of the way the concept of subculture has been applied primarily to youth cultures in terms of the relationship between agency and constraint

Black ethnographic activists: Exploring Robert Park, scientific racism, The Chicago School, and FBI files through the Black sociological experience of Charles S. Johnson and E. Franklin Frazier

Charles S. Johnson and E. Franklin Frazier were successful Black sociologists from the 1920s to 1960s, working in an age of scientific racism and eugenics, who battled racial oppression, racist discrimination, and surveillance under the Federal Bureau of Investigation. Both struggled within and against the assimilationist paradigm, yet their ethnographic and critical insights speak out today with continuing relevance in the fight against practical and institutional racial injustice. This study selectively examines Johnson and Frazier's academic careers as forgotten ethnographer activists who have been largely excluded from the dominant narrative of the Chicago School of Sociology. This article argues Robert Park offered opportunities to these Black scholars although the white university system exclusively directed their work towards race studies. Furthermore, the white discipline of sociology failed to recognize Johnson and Frazier's critical ethnographic studies as part of interactionism

Real-time new product development in financial services: Some managerial implications

A review of the various models of New Product Development (NPD) process shows that although different approaches have been proposed, they are in fact all variants on a linear theme: some may include feedback loops, but they all essentially advocate that certain steps precede, or are preceded by, others. An inevitable consequence on the Internet/World Wide Web (WWW or Web) is that such models are no longer applicable. Based on the lessons learned from the development of a new financial service offered via the Internet, we show how such assumptions of linearity need no longer be a constraint. In addition, innovativeness is not related to firm size. But the fact that the Web allows for the real-time development of new financial services based on on-going feedback from potential and current customers raises a new set of managerial issue that have to be tackled. The objective of this paper is to use the context of the recent launch of an innovative financial services product via the Web to explore the managerial changes that are starting to affect the banking industr

Distinguishing Solar Flare Types by Differences in Reconnection Regions

Observations show that magnetic reconnection and its slow shocks occur in solar flares. The basic magnetic structures are similar for long duration event (LDE) flares and faster compact impulsive (CI) flares, but the former require less non-thermal electrons than the latter. Slow shocks can produce the required non-thermal electron spectrum for CI flares by Fermi acceleration if electrons are injected with large enough energies to resonate with scattering waves. The dissipation region may provide the injection electrons, so the overall number of non-thermal electrons reaching the footpoints would depend on the size of the dissipation region and its distance from the chromosphere. In this picture, the LDE flares have converging inflows toward a dissipation region that spans a smaller overall length fraction than for CI flares. Bright loop-top X-ray spots in some CI flares can be attributed to particle trapping at fast shocks in the downstream flow, the presence of which is determined by the angle of the inflow field and velocity to the slow shocks.Comment: 15 pages TeX and 2 .eps figures, accepted to Ap.J.Let

Three Dimensional Evolution of a Relativistic Current Sheet : Triggering of Magnetic Reconnection by the Guide Field

The linear and non-linear evolution of a relativistic current sheet of pair ($e^{\pm}$) plasmas is investigated by three-dimensional particle-in-cell simulations. In a Harris configuration, it is obtained that the magnetic energy is fast dissipated by the relativistic drift kink instability (RDKI). However, when a current-aligned magnetic field (the so-called "guide field") is introduced, the RDKI is stabilized by the magnetic tension force and it separates into two obliquely-propagating modes, which we call the relativistic drift-kink-tearing instability (RDKTI). These two waves deform the current sheet so that they trigger relativistic magnetic reconnection at a crossover thinning point. Since relativistic reconnection produces a lot of non-thermal particles, the guide field is of critical importance to study the energetics of a relativistic current sheet.Comment: 12 pages, 4 figures; fixed typos and added a footnote [24

Blowing Up Safety Culture: The Lure and Trap of Accident Investigation and Continuous Improvement

Safety culture is clearly recognized as an important element of any organization. This is of particular importance for high-risk industries where complex sociotechnical systems exist. In many industries a great deal of energy, time and money continues to be expended in trying to get the culture right. Active safety programs such as the Voluntary Protection Program, peer observation programs such as behavior-based safety, planned audits and inspections from a variety of bodies both internal and external to the organization, as well as audits by regulatory bodies are regularly employed. And when something bad happens there are standard protocols for investigating accidents leading to corrective actions that seek to prevent another occurrence. This coupled with the fact that for decades there have been countless programs directed at quality and continuous improvement has led to situations where we can become captured by quality and we are led away from understanding the greater situational context. In addition, a specific intervention and step-by-step approach is described that was applied to “blow up” and then reset the safety culture of an operational facility

The spatial distribution patterns of condensed phase post-blast explosive residues formed during detonation

The continued usage of explosive devices, as well as the ever growing threat of ‘dirty’ bombs necessitates a comprehensive understanding of particle dispersal during detonation events in order to develop effectual methods for targeting explosive and/or additive remediation efforts. Herein, the distribution of explosive analytes from controlled detonations of aluminised ammonium nitrate and an RDX-based explosive composition were established by systematically sampling sites positioned around each firing. This is the first experimental study to produce evidence that the post-blast residue mass can distribute according to an approximate inverse-square law model, while also demonstrating for the first time that distribution trends can vary depending on individual analytes. Furthermore, by incorporating blast-wave overpressure measurements, high-speed imaging for fireball volume recordings, and monitoring of environmental conditions, it was determined that the principle factor affecting all analyte dispersals was the wind direction, with other factors affecting specific analytes to varying degrees. The dispersal mechanism for explosive residue is primarily the smoke cloud, a finding which in itself has wider impacts on the environment and fundamental detonation theory