2-(1,4-Dioxo-1,4-dihydro-2-naphthyl)-2-methylpropanoic acid

The sterically crowded title compound, C₁₄H₁₂O₄, crystallizes as centrosymmetric hydrogen-bonded dimers involving the carboxyl groups. The naphthoquinone ring system is folded by 11.5 (1)° about a vector joining the 1,4-C atoms, and the quinone O atoms are displaced from the ring plane, presumably because of steric interactions with the bulky substituent

A new Kempe invariant and the (non)-ergodicity of the Wang-Swendsen-Kotecky algorithm

We prove that for the class of three-colorable triangulations of a closed oriented surface, the degree of a four-coloring modulo 12 is an invariant under Kempe changes. We use this general result to prove that for all triangulations T(3L,3M) of the torus with 3<= L <= M, there are at least two Kempe equivalence classes. This result implies in particular that the Wang-Swendsen-Kotecky algorithm for the zero-temperature 4-state Potts antiferromagnet on these triangulations T(3L,3M) of the torus is not ergodic.Comment: 37 pages (LaTeX2e). Includes tex file and 3 additional style files. The tex file includes 14 figures using pstricks.sty. Minor changes. Version published in J. Phys.

Isotope shift in the Sulfur electron affinity: observation and theory

The electron affinities eA(S) are measured for the two isotopes 32S and 34S (16752.9753(41) and 16752.9776(85) cm-1, respectively). The isotope shift in the electron affinity is found to be positive, eA(34S)-eA(32S) = +0.0023(70) cm-1, but the uncertainty allows for the possibility that it may be either "normal" (eA(34S) > eA(32S)) or "anomalous" (eA(34S) < eA(32S)). The isotope shift is estimated theoretically using elaborate correlation models, monitoring the electron affinity and the mass polarization term expectation value. The theoretical analysis predicts a very large specific mass shift that counterbalances the normal mass shift and produces an anomalous isotope shift, eA(34S)-eA(32S) = - 0.0053(24) cm-1. The observed and theoretical residual isotope shifts agree with each other within the estimated uncertainties.Comment: 15 pages, 4 figure

Materiality, modernity and space: the British banks and their computer centres, 1961-1963

British banks in the 1950s were conservative, restrained and non-competitive. They were also early adopters of large-scale electronic computing technology. In contrast to their behaviour in business, their appropriation of this technology was ambitious, competitive and prone to excess. Between 1961 and 1963 the banks saw the computer as a status symbol as they deliberately constructed their first computer centres as sites for public display. Emphasising the materiality of the computer enhanced by its material setting was nothing new – IBM had done this in 1948 with its SSEC at its Manhattan headquarters – but what was interesting about the British banks was the way they in which they did this whilst at the same time upholding 400 years of tradition. The spatial demands of the computer had required a dislocation of customer accounting from branch to computer centre that was an opportunity for the banks to generate some publicity and differentiate their offerings. A number of 'performances' were held in the West End of London for invited guests, and one went as far as claiming that its computer was at the heart of the 'most advanced bank book-keeping system in the world'. The computer and its peripherals were colour coded to help explain functions and their operators were shown working in an environment of clinical efficiency. Where technologies were immaterial or opaque, for instance the computer's programs or customer account details stored on magnetic tape, they were made visible by drawing attention to their modern qualities such as speed, capacity, accuracy and size. The banks' computer centre modernity was a world away from the 'discreet modernism' coined by Jon Agar to describe the British government's use of computing technology at the same time. By combining visual, oral and written sources, I explore elements of bank computer centre design and the sociomaterial ensembles within to show how the centres were presented as homes for a computer-led orchestration of modern technologies and modern work whilst important notions of tradition were upheld in the branch. Considering the relationship between materiality, modernity and space, I suggest that the banks' computer centre modernity was a conspicuous modernism in which the spaces of the computer centre and the branch were like the two faces of Janus, looking forwards and backwards at the same time. At the computer centre one looked firmly towards the future, while in the branch the other looked cautiously behind