Electron trajectories in pulsed radiation fields

The work reported here analyzes the dynamical behavior of an electron, initially at rest, when subjected to a radiation pulse of arbitrary, but integrable, shape. This is done by a general integration procedure that has been programmed in VAXIMA. Upon choosing a specific shape for the pulse, VAXIMA finds both the space-time trajectory and the four-momentum of the electron. These are obtained in analytic or numerical form - or both - at the choice of the user. Several examples of analytical and numerical solutions, for different pulse shapes, are given

Theoretical analysis of spectral lines of one- and two-electron ions in hot plasmas

We discuss the line shapes for the 1s-2p, 1s-3p and (ls)/sup 2/ - 1s2p, (1s)/sup 2/ - 1s3p absorption lines in hot plasmas. In our model calculations the perturbing ions are considered quasi-static and widths due to collisions with electrons are calculated in the impact approximation. The collective effect of the plasma electrons is accounted for by a self-consistent model or by a simple Debye-Hueckel screening. These models in general predict different line shapes. We present calculations for the HeII, SiXIV and SiXIII ions

Searching Techniques for Integral Tables

We describe the design of data structures and a computer program for storing a table of symbolic indefinite or de nite integrals and retrieving user-requested integrals on demand. Typical times are so short that a preliminary look-up attempt prior to any algorithmic integration approach seems justified. In one such test for a table with around 700 entries, matches were found requiring an average of 2.8 milliseconds per request, on a Hewlett Packard 9000/712 workstation

Searching Techniques for Integral Tables

We describe the design of data structures and a computer program for storing a table of symbolic indefinite or definite integrals and retrieving user-requested integrals on demand. Typical times are so short that a preliminary look-up attempt prior to any algorithmic integration approach seems justified. In one such test for a table with around 700 entries, matches were found requiring an average of 2.8 milliseconds per request, on a Hewlett Packard 9000/712 workstation. 1 Introduction and objectives A goal of our recent work is to explore storage and retrieval of mathematical knowledge in a computer problem-solving environment. In particular we have considered how to supplement a computer algebra system's procedures for computing the form of indefinite or definite integrals by including in the system the mass of integrals that have been tabulated during the last two centuries. Of course some of this tabulated material (and more) can be computed algorithmically, but some of it cannot..

‘The Muslim woman activist’: solidarity across difference in the movement against the ‘War on Terror’

Feminist scholars have widely noted the centrality of gendered discourses to the ‘War on Terror’. This article shows how gendered narratives also shaped the collective identities of those opposing the ‘War on Terror’. Using interview data and analysis of newspaper editorials from movement leaders alongside focus groups with grassroots Muslim women activists, this article demonstrates how, in responding to the cynical use of women’s rights to justify war, participants in the anti-‘War on Terror’ movement offered an alternative story. Movement activists deployed representations of Muslim women’s agency to challenge the trope of the ‘oppressed Muslim woman’. I argue that these representations went beyond strategic counternarratives and offered an emotional basis for solidarity. Yet, respondents in the focus groups illustrated the challenges of seeking agency through an ascribed identity; in that they simultaneously refused and relied upon dominant terms of the debate about Muslim women