\u27Formation in Distinctive Dimensions of Our Way of Proceeding\u27: Preparation of Lay Directors of Works in Jesuit Schools

The purpose of the study was to determine how lay directors of works in Jesuits West secondary schools can be formed to best serve as faith leaders. The study consisted of secondary research in which interview data and surveys from studies on lay formation in Jesuit universities and lay leadership of Bay Area Catholic High Schools were used to determine whether or not formation of lay directors of works in faith leadership is possible, what the objectives of that training should be, and how that training can be offered. This analysis determined that lay formation is both possible and necessary. It also found that lay formation should focus on both the interior spiritual lives of the leaders as well as their familiarity with the history, philosophy and jargon of the Jesuits. Programs now exist that successfully accomplish those two goals

Entropic-acoustic instability of shocked Bondi accretion I. What does perturbed Bondi accretion sound like ?

In the radial flow of gas into a black hole (i.e. Bondi accretion), the infall of any entropy or vorticity perturbation produces acoustic waves propagating outward. The dependence of this acoustic flux on the shape of the perturbation is investigated in detail. This is the key process in the mechanism of the entropic-acoustic instability proposed by Foglizzo & Tagger (2000) to explain the instability of Bondi-Hoyle-Lyttleton accretion. These acoustic waves create new entropy and vorticity perturbations when they reach the shock, thus closing the entropic-acoustic cycle. With an adiabatic index 1<gamma<=5/3, the linearized equations describing the perturbations of the Bondi flow are studied analytically and solved numerically. The fundamental frequency of this problem is the cut-off frequency of acoustic refraction, below which ingoing acoustic waves are refracted out. This cut-off is significantly smaller than the Keplerian frequency at the sonic radius and depends on the latitudinal number l of the perturbations. When advected adiabatically inward, entropy and vorticity perturbations trigger acoustic waves propagating outward, with an efficiency which is highest for non radial perturbations l=1. The outgoing acoustic flux produced by the advection of vorticity perturbations is always moderate and peaks at rather low frequency. By contrast, the acoustic flux produced by an entropy wave is highest close to the refraction cut-off. It can be very large if gamma is close to 5/3. These results suggest that the shocked Bondi flow with gamma=5/3 is strongly unstable with respect to the entropic-acoustic mechanism.Comment: 14 pages, 11 figures, accepted for publication in A&

Complex Patterns in Reaction-Diffusion Systems: A Tale of Two Front Instabilities

Two front instabilities in a reaction-diffusion system are shown to lead to the formation of complex patterns. The first is an instability to transverse modulations that drives the formation of labyrinthine patterns. The second is a Nonequilibrium Ising-Bloch (NIB) bifurcation that renders a stationary planar front unstable and gives rise to a pair of counterpropagating fronts. Near the NIB bifurcation the relation of the front velocity to curvature is highly nonlinear and transitions between counterpropagating fronts become feasible. Nonuniformly curved fronts may undergo local front transitions that nucleate spiral-vortex pairs. These nucleation events provide the ingredient needed to initiate spot splitting and spiral turbulence. Similar spatio-temporal processes have been observed recently in the ferrocyanide-iodate-sulfite reaction.Comment: Text: 14 pages compressed Postscript (90kb) Figures: 9 pages compressed Postscript (368kb

Steady-State and Time-Resolved Spectroscopy of F420 Extracted from Methanogen Cells

The methanogen electron carrier F420 was extracted from a methanogen cell culture, Methanobrevibacter ruminantium, and separated from other cell components by a single anion exchange chromatographic process. The extent of separation was determined spectroscopically. The fluorescence lifetime of F420 at pH 7.5 is ~4.2 nanoseconds

Equations over free inverse monoids with idempotent variables

We introduce the notion of idempotent variables for studying equations in inverse monoids. It is proved that it is decidable in singly exponential time (DEXPTIME) whether a system of equations in idempotent variables over a free inverse monoid has a solution. The result is proved by a direct reduction to solve language equations with one-sided concatenation and a known complexity result by Baader and Narendran: Unification of concept terms in description logics, 2001. We also show that the problem becomes DEXPTIME hard , as soon as the quotient group of the free inverse monoid has rank at least two. Decidability for systems of typed equations over a free inverse monoid with one irreducible variable and at least one unbalanced equation is proved with the same complexity for the upper bound. Our results improve known complexity bounds by Deis, Meakin, and Senizergues: Equations in free inverse monoids, 2007. Our results also apply to larger families of equations where no decidability has been previously known.Comment: 28 pages. The conference version of this paper appeared in the proceedings of 10th International Computer Science Symposium in Russia, CSR 2015, Listvyanka, Russia, July 13-17, 2015. Springer LNCS 9139, pp. 173-188 (2015

Possible direct method to determine the radius of a star from the spectrum of gravitational wave signals

We computed the spectrum of gravitational waves from a dust disk star of radius R inspiraling into a Kerr black hole of mass M and specific angular momentum a. We found that when R is much larger than the wave length of the quasinormal mode, the spectrum has several peaks and the separation of peaks $\Delta\omega$ is proportional to $R^{-1}$ irrespective of M and a. This suggests that the radius of the star in coalescing binary black hole - star systems may be determined directly from the observed spectrum of gravitational wave. This also suggests that the spectrum of the radiation may give us important information in gravitational wave astronomy as in optical astronomy.Comment: 4 pages with 3 eps figures, revtex.sty, accepted for publication in Phys. Rev. Let

From Labyrinthine Patterns to Spiral Turbulence

A new mechanism for spiral vortex nucleation in nongradient reaction diffusion systems is proposed. It involves two key ingredients: An Ising-Bloch type front bifurcation and an instability of a planar front to transverse perturbations. Vortex nucleation by this mechanism plays an important role in inducing a transition from labyrinthine patterns to spiral turbulence. PACS numbers: 05.45.+b, 82.20.MjComment: 4 pages uuencoded compressed postscrip

Applying black hole perturbation theory to numerically generated spacetimes

Nonspherical perturbation theory has been necessary to understand the meaning of radiation in spacetimes generated through fully nonlinear numerical relativity. Recently, perturbation techniques have been found to be successful for the time evolution of initial data found by nonlinear methods. Anticipating that such an approach will prove useful in a variety of problems, we give here both the practical steps, and a discussion of the underlying theory, for taking numerically generated data on an initial hypersurface as initial value data and extracting data that can be considered to be nonspherical perturbations.Comment: 14 pages, revtex3.0, 5 figure

Dipolar Relaxation in an ultra-cold Gas of magnetically trapped chromium atoms

We have investigated both theoretically and experimentally dipolar relaxation in a gas of magnetically trapped chromium atoms. We have found that the large magnetic moment of 6 $\mu_B$ results in an event rate coefficient for dipolar relaxation processes of up to $3.2\cdot10^{-11}$ cm$^{3}$s$^{-1}$ at a magnetic field of 44 G. We present a theoretical model based on pure dipolar coupling, which predicts dipolar relaxation rates in agreement with our experimental observations. This very general approach can be applied to a large variety of dipolar gases.Comment: 9 pages, 9 figure