Global Dimension of Polynomial Rings in Partially Commuting Variables

For any free partially commutative monoid $M(E,I)$, we compute the global dimension of the category of $M(E,I)$-objects in an Abelian category with exact coproducts. As a corollary, we generalize Hilbert's Syzygy Theorem to polynomial rings in partially commuting variables.Comment: 11 pages, 2 figure

Study of zero-gravity, vapor/liquid separators

Heat exchange, mechanical separation, surface tension, and dielectrophoretic methods of separating vapor from liquid at zero gravity for vapor ventin

A mechanism model of the effect of hedonic product consumption on well-being

In response to recent calls for research into activities that may increase happiness, this study uses longitudinal data to investigate changes in within-subject, instead of between-subject, well-being. In the context of hedonic product consumption, this study reveals a mechanism by which consumption influences well-being through the mediating effect of satisfaction with associated life domains. Four years of data from a large national panel survey show that consuming hedonic products has indirect effects on well-being, by improving consumers' satisfaction within relevant life domains. High hedonic consumption improves satisfaction with relevant life domains, primarily through more frequent consumption of low-cost hedonic products rather than less frequent consumption of high-cost hedonic products

Invariant manifolds and the geometry of front propagation in fluid flows

Recent theoretical and experimental work has demonstrated the existence of one-sided, invariant barriers to the propagation of reaction-diffusion fronts in quasi-two-dimensional periodically-driven fluid flows. These barriers were called burning invariant manifolds (BIMs). We provide a detailed theoretical analysis of BIMs, providing criteria for their existence, a classification of their stability, a formalization of their barrier property, and mechanisms by which the barriers can be circumvented. This analysis assumes the sharp front limit and negligible feedback of the front on the fluid velocity. A low-dimensional dynamical systems analysis provides the core of our results.Comment: 14 pages, 11 figures. To appear in Chaos Focus Issue: Chemo-Hydrodynamic Patterns and Instabilities (2012

Personal branding for academic faculty: a new social phenomenon for Russian higher education?

The paper reports the results of a pilot study on the extent to which academic faculty at Rus-sian higher education institutions engage in personal branding. The paper places personal branding in the context of an increased reliance on social media by Russian higher educa-tion institutions and examines the question of whether personal branding might be conducive to academic faculty’s career advancement. Employing analysis of publicly available data, the authors demonstrate that leading Russian universities use social media to raise their pro-file. Analysis of the Facebook, Instagram and vk social media accounts of academic faculty at a prominent Russian university demonstrated that almost a third of academic faculty en-gaged in personal branding to some extent, and almost 7% engaged in strategic personal branding. This was limited, however, to senior faculty members and it is unclear whether their strategic personal branding impacts on their career advancement or is merely reflec-tive of it. It remains to be seen whether this trend will ‘trickle down’ and become more prev-alent among Russian academic faculty

100 MHz Amplitude and Polarization Modulated Optical Source for Free-Space Quantum Key Distribution at 850 nm

We report on an integrated photonic transmitter of up to 100 MHz repetition rate, which emits pulses centered at 850 nm with arbitrary amplitude and polarization. The source is suitable for free space quantum key distribution applications. The whole transmitter, with the optical and electronic components integrated, has reduced size and power consumption. In addition, the optoelectronic components forming the transmitter can be space-qualified, making it suitable for satellite and future space missions.Comment: 6 figures, 2 table

Instability of toroidal magnetic field in jets and plerions

Jets and pulsar-fed supernova remnants (plerions) tend to develop highly organized toroidal magnetic field. Such a field structure could explain the polarization properties of some jets, and contribute to their lateral confinement. A toroidal field geometry is also central to models for the Crab Nebula - the archetypal plerion - and leads to the deduction that the Crab pulsar's wind must have a weak magnetic field. Yet this `Z-pinch' field configuration is well known to be locally unstable, even when the magnetic field is weak and/or boundary conditions slow or suppress global modes. Thus, the magnetic field structures imputed to the interiors of jets and plerions are unlikely to persist. To demonstrate this, I present a local analysis of Z-pinch instabilities for relativistic fluids in the ideal MHD limit. Kink instabilities dominate, destroying the concentric field structure and probably driving the system toward a more chaotic state in which the mean field strength is independent of radius (and in which resistive dissipation of the field may be enhanced). I estimate the timescales over which the field structure is likely to be rearranged and relate these to distances along relativistic jets and radii from the central pulsar in a plerion. I conclude that a concentric toroidal field is unlikely to exist well outside the Crab pulsar's wind termination shock. There is thus no dynamical reason to conclude that the magnetic energy flux carried by the pulsar wind is much weaker than the kinetic energy flux. Abandoning this inference would resolve a long-standing puzzle in pulsar wind theory.Comment: 28 pages, plain TeX. Accepted for publication in Ap