Infrared Behaviour of Massless Integrable Flows entering the Minimal Models from phi_31

It is known that any minimal model M_p receives along its phi_31 irrelevant direction *two* massless integrable flows: one from M_{p+1} perturbed by phi_{13}, the other from Z_{p-1} parafermionic model perturbed by its generating parafermion field. By comparing Thermodynamic Bethe Ansatz data and ``predictions'' of infrared Conformal Perturbation Theory we show that these two flows are received by M_p with opposite coupling constants of the phi_31 irrelevant perturbation. Some comments on the massless S matrices of these two flows are added.Comment: 12 pages, Latex - One misprinted (uninfluent) coefficient corrected in Tab.

Going by the moon and the stars: Stories of two Russian Mennonite women

The stories of women\u27s religious lives are essential to understanding religion. This thesis records and interprets two Russian Mennonite women\u27s religious lives, using methods of feminist ethnography. The first chapter is a video which presents Agatha Janzen and Katja Enns talking about their childhoods in the Soviet Union in the 1920s and 305, their flight to Germany during World War ll, and their subsequent emigration and life in Canada. Chapter 2 tells and interprets Agatha\u27s and Katja\u27s experiences of marriage during the war, and the effect of their status as widow (Agatha) and single mother (Katja) upon their entry into the Canadian Mennonite church. Chapter 3 discusses the structure and content of the women\u27s stories about the war, and the ways they have integrated their war stories into their religious life. Chapter 4 considers the ways Agatha and Katja are Mennonite today, looking especially at the role of prayer, preaching, and personal relationships in their lives. The last chapter discusses the process of deciding what is religious about a life, the merits and tensions of feminist ethnography, and the implications of video for life history. Reflections on the effects of this work on Kalja, Agatha, and me conclude the study

A general hybrid radiation transport scheme for star formation simulations on an adaptive grid

Radiation feedback plays a crucial role in the process of star formation. In order to simulate the thermodynamic evolution of disks, filaments, and the molecular gas surrounding clusters of young stars, we require an efficient and accurate method for solving the radiation transfer problem. We describe the implementation of a hybrid radiation transport scheme in the adaptive grid-based FLASH general magnetohydrodynamics code. The hybrid scheme splits the radiative transport problem into a raytracing step and a diffusion step. The raytracer captures the first absorption event, as stars irradiate their environments, while the evolution of the diffuse component of the radiation field is handled by a flux-limited diffusion (FLD) solver. We demonstrate the accuracy of our method through a variety of benchmark tests including the irradiation of a static disk, subcritical and supercritical radiative shocks, and thermal energy equilibration. We also demonstrate the capability of our method for casting shadows and calculating gas and dust temperatures in the presence of multiple stellar sources. Our method enables radiation-hydrodynamic studies of young stellar objects, protostellar disks, and clustered star formation in magnetized, filamentary environments.Comment: 16 pages, 15 figures, accepted to Ap

Simulating protostellar evolution and radiative feedback in the cluster environment

Radiative feedback is among the most important consequences of clustered star formation inside molecular clouds. At the onset of star formation, radiation from massive stars heats the surrounding gas, which suppresses the formation of many low‐mass stars. When simulating pre‐main‐sequence stars, their stellar properties must be defined by a pre‐stellar model. Different approaches to pre‐stellar modelling may yield quantitatively different results. In this paper, we compare two existing pre‐stellar models under identical initial conditions to gauge whether the choice of model has any significant effects on the final population of stars. The first model treats stellar radii and luminosities with a zero‐age main‐sequence (ZAMS) model, while separately estimating the accretion luminosity by interpolating to published pre‐stellar tracks. The second, more accurate pre‐stellar model self‐consistently evolves the radius and luminosity of each star under highly variable accretion conditions. Each is coupled to a raytracing‐based radiative feedback code that also treats ionization. The impact of the self‐consistent model is less ionizing radiation and less heating during the early stages of star formation. This may affect final mass distributions. We noted a peak stellar mass reduced by 8 per cent from 47.3 to 43.5 M⊙ in the evolutionary model, relative to the track‐fit model. Also, the difference in mass between the two largest stars in each case is reduced from 14 to 7.5 M⊙. The H ii regions produced by these massive stars were also seen to flicker on time‐scales down to the limit imposed by our time‐step (<560 yr), rapidly changing in size and shape, confirming previous cluster simulations using ZAMS‐based estimates for pre‐stellar ionizing flu

A Novel Representation for Riemannian Analysis of Elastic Curves in R^{n}

We propose a novel representation of continuous, closed curves in Rn that is quite efficient for analyzing their shapes. We combine the strengths of two important ideas-elastic shape metric and path-straightening methods - in shape analysis and present a fast algorithm for finding geodesies in shape spaces. The elastic metric allows for optimal matching of features while path-straightening provides geodesies between curves. Efficiency results from the fact that the elastic metric becomes the simple L2 metric in the proposed representation. We present step-by-step algorithms for computing geodesies in this framework, and demonstrate them with 2-D as well as 3-D examples

A Contribution of the Trivial Connection to Jones Polynomial and Witten's Invariant of 3d Manifolds I

We use the Chern-Simons quantum field theory in order to prove a recently conjectured limitation on the 1/K expansion of the Jones polynomial of a knot and its relation to the Alexander polynomial. This limitation allows us to derive a surgery formula for the loop corrections to the contribution of the trivial connection to Witten's invariant. The 2-loop part of this formula coincides with Walker's surgery formula for Casson-Walker invariant. This proves a conjecture that Casson-Walker invariant is a 2-loop correction to the trivial connection contribution to Witten's invariant of a rational homology sphere. A contribution of the trivial connection to Witten's invariant of a manifold with nontrivial rational homology is calculated for the case of Seifert manifolds.Comment: 28 page