Comment on ``Method to analyze electromechanical stability of dielectric elastomers" [Appl. Phys. Lett. 91, 061921 (2007)]

The model of Zhao and Suo can be readily generalized to predict the critical breakdown electric field $E_c$ value of elastomers with arbitrary elastic strain energy function. An explicit expression for $E_c$ is presented for elastomeric thin films under biaxial strain and comparisons are made with experimental data using a two term Ogden rubber elasticity model. Simplified results for uniaxial and for equi-biaxial stress provide further insight into the findings of Zhao and Suo.Comment: 2 page

Professor Cecil Gray CBE KCSG FRCS FRCP FRCA in interview with Dr Max Blythe: Interview 1

Part One Professor T Cecil Gray, professor of anaesthesia at the University of Liverpool from 1959 to 1976, has a distinguished reputation for training, teaching and research in anaesthesia. He begins the interview with discussion  of a Liverpool background, and education at preparatory school and Ampleforth College, where he studied science and also developed an interest in music and drama. He goes on to speak of a two-month period as a novice monk at Ampleforth before deciding to study medicine at the University of Liverpool. As a student on the pre-clinical course he enjoyed the anatomy classes  of Professor Wood, and during his clinical training the professor of medicine,  Henry Cohen, and the surgeon Charles Wells were influential and supportive  figures. Professor Gray then talks of his marriage in 1937 and a decision  to become a partner in a general practice in Liverpool, and he goes on   to describe the work of the busy practice: holding surgeries, dispensing medicines, making home visits, providing a domiciliary obstetric service, and caring for many patients living in conditions of poverty. A discussion         then follows of Professor Gray's developing interest in anaesthesia, and  anaesthetic practice at this time, when the administration of general  anaesthesia was undertaken by general practitioners and hospital staff  who were not medically qualified .Part Two In the second part of the interview, Professor Gray talks of buying a  general practice in Liverpool in 1939, and the experience of working as a single-handed practitioner. At this time, wishing to gain specialist  knowledge of anaesthesia, he received training on two afternoons a week  from the renowned Liverpool general practitioner and anaesthetist, R J Minnitt, who was a prominent member of the Liverpool Society of Anaesthetists. Minnitt encouraged him to take the Diploma in Anaesthetics (DA), which required that one thousand anaesthetics should be recorded by the candidate. Professor Gray speaks of Minnitt's contribution to the specialty of anaesthesia, and of how he developed a machine for self-administration of nitrous oxide   and air for the relief of pain in labour, which was subsequently authorised  by the Central Midwives Board for supervision by midwives who had received suitable instruction. At the start of the Second World War, Professor Gray was turned down by the forces because he suffered from asthma. He continued in general practice, at the same time working as an anaesthetist,         until 1941, when he became a full-time anaesthetist at the Northern General Hospital in Liverpool. In the final part of the interview, Professor Gray talks of volunteering for service and acceptance by the Royal Army Medical Corps in 1942, active service attached to a neurosurgical unit in North  Africa, and the experience of being invalided home in 1944 after contracting bronchial pneumonia

Dyck Paths, Motzkin Paths and Traffic Jams

It has recently been observed that the normalization of a one-dimensional out-of-equilibrium model, the Asymmetric Exclusion Process (ASEP) with random sequential dynamics, is exactly equivalent to the partition function of a two-dimensional lattice path model of one-transit walks, or equivalently Dyck paths. This explains the applicability of the Lee-Yang theory of partition function zeros to the ASEP normalization. In this paper we consider the exact solution of the parallel-update ASEP, a special case of the Nagel-Schreckenberg model for traffic flow, in which the ASEP phase transitions can be intepreted as jamming transitions, and find that Lee-Yang theory still applies. We show that the parallel-update ASEP normalization can be expressed as one of several equivalent two-dimensional lattice path problems involving weighted Dyck or Motzkin paths. We introduce the notion of thermodynamic equivalence for such paths and show that the robustness of the general form of the ASEP phase diagram under various update dynamics is a consequence of this thermodynamic equivalence.Comment: Version accepted for publicatio

Reports Of Conferences, Institutes, And Seminars

This quarter\u27s column offers coverage of multiple sessions from the 2016 Electronic Resources & Libraries (ER&L) Conference, held April 3–6, 2016, in Austin, Texas. Topics in serials acquisitions dominate the column, including reports on altmetrics, cost per use, demand-driven acquisitions, and scholarly communications and the use of subscriptions agents; ERMS, access, and knowledgebases are also featured

Book Reviews

Law of Domestic Relations By Homer H. Clark, Jr. St. Paul,Minn.: West Publishing Co., 1968. Pp. XIX, 754. $12.00. reviewer: T.A. Smedley ============================== Law and the Social Role of Science Harry W. Jones, Editor New York: Rockefeller University Press, 1967. Pp. 243.$6.00. reviewer: E. Blythe Staso

Parasites on parasites:Coupled fluctuations in stacked contact processes

We present a model for host-parasite dynamics which incorporates both vertical and horizontal transmission as well as spatial structure. Our model consists of stacked contact processes (CP), where the dynamics of the host is a simple CP on a lattice while the dynamics of the parasite is a secondary CP which sits on top of the host-occupied sites. In the simplest case, where infection does not incur any cost, we uncover a novel effect: a non-monotonic dependence of parasite prevalence on host turnover. Inspired by natural examples of hyperparasitism, we extend our model to multiple levels of parasites and identify a transition between the maintenance of a finite and infinite number of levels, which we conjecture is connected to a roughening transition in models of surface growth

When is a bottleneck a bottleneck?

Bottlenecks, i.e. local reductions of capacity, are one of the most relevant scenarios of traffic systems. The asymmetric simple exclusion process (ASEP) with a defect is a minimal model for such a bottleneck scenario. One crucial question is "What is the critical strength of the defect that is required to create global effects, i.e. traffic jams localized at the defect position". Intuitively one would expect that already an arbitrarily small bottleneck strength leads to global effects in the system, e.g. a reduction of the maximal current. Therefore it came as a surprise when, based on computer simulations, it was claimed that the reaction of the system depends in non-continuous way on the defect strength and weak defects do not have a global influence on the system. Here we reconcile intuition and simulations by showing that indeed the critical defect strength is zero. We discuss the implications for the analysis of empirical and numerical data.Comment: 8 pages, to appear in the proceedings of Traffic and Granular Flow '1

The Grand-Canonical Asymmetric Exclusion Process and the One-Transit Walk

The one-dimensional Asymmetric Exclusion Process (ASEP) is a paradigm for nonequilibrium dynamics, in particular driven diffusive processes. It is usually considered in a canonical ensemble in which the number of sites is fixed. We observe that the grand-canonical partition function for the ASEP is remarkably simple. It allows a simple direct derivation of the asymptotics of the canonical normalization in various phases and of the correspondence with One-Transit Walks recently observed by Brak et.al.Comment: Published versio

An introduction to phase transitions in stochastic dynamical systems

We give an introduction to phase transitions in the steady states of systems that evolve stochastically with equilibrium and nonequilibrium dynamics, the latter defined as those that do not possess a time-reversal symmetry. We try as much as possible to discuss both cases within the same conceptual framework, focussing on dynamically attractive `peaks' in state space. A quantitative characterisation of these peaks leads to expressions for the partition function and free energy that extend from equilibrium steady states to their nonequilibrium counterparts. We show that for certain classes of nonequilibrium systems that have been exactly solved, these expressions provide precise predictions of their macroscopic phase behaviour.Comment: Pedagogical talk contributed to the "Ageing and the Glass Transition" Summer School, Luxembourg, September 2005. 12 pages, 8 figures, uses the IOP 'jpconf' document clas

Relaxation time in a non-conserving driven-diffusive system with parallel dynamics

We introduce a two-state non-conserving driven-diffusive system in one-dimension under a discrete-time updating scheme. We show that the steady-state of the system can be obtained using a matrix product approach. On the other hand, the steady-state of the system can be expressed in terms of a linear superposition Bernoulli shock measures with random walk dynamics. The dynamics of a shock position is studied in detail. The spectrum of the transfer matrix and the relaxation times to the steady-state have also been studied in the large-system-size limit.Comment: 10 page