Neutrino Production and Transport during Gravitational Collapse

The P-N method is developed to describe the transport of neutrinos in collapsing stellar cores, and the multigroup flux limited diffusion and equilibrium diffusion approximations are obtained from it. An effective Lagrangian for weak neutral and charged current neutrino interactions which is applicable to low energy neutrino processes is derived. The neutrino source functions which enter into the P-N equations are given a many body theory formulation in terms of weak current-current correlation functions. Within this framework, we deal, in turn, with the scattering reactions νA → νA, νA → νA*, νN → νN (both for non-degenerate and degenerate nucleons), νe → νe, and νν → νν, and the production and absorption reactions e-p ⇄ nνe, e+n ⇄ pν̅e, e-AZ ⇄ A(Z-1) νe, e+e- ⇄ νν̅, and γpℓ ⇄ νν̅. These equations are then applied to the various phases of neutrino flow during iron core collapse: the transparent stage to the onset of trapping; the approach of electron neutrinos to beta-equilibrium; the evolution of the muon neutrino and antineutrino distribution functions towards the Fermi-Dirac form; the conditions under which νµ ν̅µ radiative energy loss exceeds the νe loss; comparison of the P-1 and flux limited diffusion methods of spatial transport in a static pre-bounce core

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices

The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included

2011 program of study : shear turbulence : onset and structure

The theme for the Program in Geophysical Fluid Dynamics for the summer of 2011 was Shear Turbulence: onset and structure. Ten days of principal lectures by FabianWale e and Rich Kerswell began the summer, and a large number of seminars on this and a variety of other topics then continued through the eighth week. These lectures are presented in these Proceedings and form (we believe) the most complete, connected account of this subject) Eleven fellows from around the globe helped to record the principal lectures, and each carried out a project of his/her own, presented in seminar during the tenth and nal week. All these lectures and projects are also presented in this Proceedings volume. The further seminars presented throughout the summer by visitors and (in some cases) by GFD faculty are also listed here. The popular Sears Lecture was given by L. Mahadevan. The title was On growth and form: geometry, physics and biology. It was indeed popular, drawing a large and enthusiastic audience.Funding was provided by the National Science Foundation under Grant No. OCE-0824636 and the Office of Naval Research under Contract No. N00014-09-1084

Present value models of agricultural land prices in England and Wales

This study employs recently developed techniques in time series econometrics to estimate linear models of equilibrium price determination in a competitive market for durable assets. Motivating this study is the unstructured approach employed in previous land price research, where the theoretical model of agent behaviour is invariably mis-specified or left undeveloped and the empirical model prone to the problems of spurious regression. The joint issues of theoretical and statistical congruence play important roles here. Specifically, a theoretical model is developed in which market participants are assumed to price land using present value methods. At the market level this yields a reduced form expression of equilibrium price determination which can be estimated empirically using aggregate data for England and Wales. The concepts of error correction and cointegration are then investigated and applied to the land price model. A unique long run relationship is identified between real agricultural land prices, inflation and real agricultural rents. Taking account of inflation-hedging as a motivation for acquiring farmland, land prices are shown to be principally determined by the returns to land, as embodied by market rents. The empirical model is also congruent with theoretical predictions regarding the unit elasticity between asset prices and returns. The error correction representation of the cointegrating set indicates that the short run response of land prices to rent and inflation is larger than the long run response. Consequently, land prices initially overshoot their equilibrium values following changes in rents or inflation. The period of adjustment to long run equilibrium lasts around three or fours years. The long run real rate of discount on agricultural land is estimated at 3.6% confirming the widely held belief that real rates of return on farmland are low. Present value models incorporating naive, adaptive and rational expectations are also estimated and the adaptive model is favoured by the data