Exact norm-conserving stochastic time-dependent Hartree-Fock

We derive an exact single-body decomposition of the time-dependent Schroedinger equation for N pairwise-interacting fermions. Each fermion obeys a stochastic time-dependent norm-preserving wave equation. As a first test of the method we calculate the low energy spectrum of Helium. An extension of the method to bosons is outlined.Comment: 21 pages, 3 figures, LaTeX fil

Comparative evaluation of pressure distribution between horizontal and vertical wells in a reservoir (edge water drive)

This paper presents comparative analysis between the pressure behavior of a horizontal well and a vertical well both subject to edge water drive. Green and source function were used to evaluate the performance of horizontal well and vertical well, eventually, compared based dimensionless pressures and pressure derivatives computed by varying the reservoir geometry. Results presented as type curves show that the rate of decline of the pressure derivative curve is more sharper and sensitive in vertical well than horizontal well of the same geometry indicating a shorter period of clean oil production in vertical well than the horizontal well. The period of radial flow as shown by the horizontal flattened part of the type curve indicate that for all reservoir geometry, the horizontal well will be able to sustain longer period of the radial flow than vertical well given infinite conductivity condition.Keywords: dimensionless pressure, dimensionless pressure derivative, horizontal well, vertical well, edge water drive, radial flo

Thermal Decomposition and Combustion of γ-irradiated Polyamide 6 Containing Phosphorus Oxynitride or Phospham

Polyamide 6 (PA-6) containing the fire retardants phosphorus oxynitride ((PON)m) or phospham ((PN2H)n) was exposed to 60Co-γ-rays (absorbed dose: 1.0–4.0 MGy). The irradiation led to crosslinking of the polymer which caused an increase in the char yield and a decrease in the flammability of the polymer. The combustion behavior was strongly affected by irradiation: dripping was totally prevented in the case of system PA-6/(PN2H)n and strongly retarded in the case of system PA-6/(PON)m. The thermal stability of the system PA-6/(PN2H)n decreased with increasing absorbed dose whereas the thermal stability of the system PA-6/(PON)m did not change

Numerical Methods for Stochastic Differential Equations

Stochastic differential equations (sdes) play an important role in physics but existing numerical methods for solving such equations are of low accuracy and poor stability. A general strategy for developing accurate and efficient schemes for solving stochastic equations in outlined here. High order numerical methods are developed for integration of stochastic differential equations with strong solutions. We demonstrate the accuracy of the resulting integration schemes by computing the errors in approximate solutions for sdes which have known exact solutions

Alternative splicing produces transcripts encoding two forms of the α subunit of GTP-binding protein G_o

The α subunit of the guanine nucleotide-binding protein G_o ("o" for other) is believed to mediate signal transduction between a variety of receptors and effectors. cDNA clones encoding two forms of G_o α subunit were isolated from a mouse brain library. These two forms, which we call G_(o)Aα and G_(o)Bα, appear to be the products of alternative splicing. G_(o)Aα differs from G_(o)Bα over the C-terminal third of the deduced protein sequence. Both forms are predicted to be substrates for ADP-ribosylation by pertussis toxin. G_(o)Aα transcripts are present in a variety of tissues but are most abundant in brain. The G_(o)Bα transcript is expressed at highest levels in brain and testis. It is possible that G_(o)Aα and G_(o)Bα have different functions

Diversity of the G-protein family: sequences from five additional α subunits in the mouse

Biochemical analysis has revealed a number of guanine nucleotide-binding regulatory proteins (G proteins) that mediate signal transduction in mammalian systems. Characterization of their cDNAs uncovered a family of proteins with regions of highly conserved amino acid sequence. To examine the extent of diversity of the G protein family, we used the polymerase chain reaction to detect additional gene products in mouse brain and spermatid RNA that share these conserved regions. Sequences corresponding to six of the eight known G protein alpha subunits were obtained. In addition, we found sequences corresponding to five newly discovered alpha subunits. Our results suggest that the complexity of the G protein family is much greater than previously suspected

“Too many actors and too few jobs” : a case for curriculum extension in UK vocational actor training

This article questions the current situation for vocational acting training (VAT) in the UK. It aims to provide an update on the report into burgeoning provision of acting training (and the attempt to address subsequent high rates of actor unemployment) that was originally undertaken by the Calouste Gulbenkian Foundation (CGF, 1975) in their publication entitled Going on the Stage. The article will suggest that the continued proliferation of VAT offered at tertiary level, allied to the dearth of career opportunities for graduates, means that the current training offer is not entirely fit for purpose. It will further propose that VAT requires a widening of the curriculum offer in order to provide meaningful vocational workplace readiness for course graduates at a time when, as Malcolm Sinclair, president of the British actors' union, Equity, acknowledges, 'there are too many actors and too few jobs' (in Clark, 2014a: 17). To address the question of VAT and employability in the UK, this article will reconsider the three questions initially posed in Going on the Stage (CGF, 1975: 7). These were: why is drama training necessary, to what extent do the present arrangements fall short of the ideal, and what should VAT entail? By re-posing these questions, this article will present the contemporary context of VAT, review the status of progression rates into employment, and propose a case for curriculum extension in light of the findings

On Recurrent Reachability for Continuous Linear Dynamical Systems

The continuous evolution of a wide variety of systems, including continuous-time Markov chains and linear hybrid automata, can be described in terms of linear differential equations. In this paper we study the decision problem of whether the solution $\boldsymbol{x}(t)$ of a system of linear differential equations $d\boldsymbol{x}/dt=A\boldsymbol{x}$ reaches a target halfspace infinitely often. This recurrent reachability problem can equivalently be formulated as the following Infinite Zeros Problem: does a real-valued function $f:\mathbb{R}_{\geq 0}\rightarrow\mathbb{R}$ satisfying a given linear differential equation have infinitely many zeros? Our main decidability result is that if the differential equation has order at most $7$, then the Infinite Zeros Problem is decidable. On the other hand, we show that a decision procedure for the Infinite Zeros Problem at order $9$ (and above) would entail a major breakthrough in Diophantine Approximation, specifically an algorithm for computing the Lagrange constants of arbitrary real algebraic numbers to arbitrary precision.Comment: Full version of paper at LICS'1

Nicotinic autoreceptors in the rat hippocampus regulate acetylcholine release

SIGLEAvailable from British Library Document Supply Centre- DSC:DX183268 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Suppression of decoherence via strong intra-environmental coupling

We examine the effects of intra-environmental coupling on decoherence by constructing a low temperature spin--spin-bath model of an atomic impurity in a Debye crystal. The impurity interacts with phonons of the crystal through anti-ferromagnetic spin-spin interactions. The reduced density matrix of the central spin representing the impurity is calculated by dynamically integrating the full Schroedinger equation for the spin--spin-bath model for different thermally weighted eigenstates of the spin-bath. Exact numerical results show that increasing the intra-environmental coupling results in suppression of decoherence. This effect could play an important role in the construction of solid state quantum devices such as quantum computers.Comment: 4 pages, 3 figures, Revtex fil