Clathrate formation and dissociation in vapor/water/ice/hydrate systems in SBA-15, sol-gel and CPG porous media, as probed by NMR relaxation, novel protocol NMR cryoporometry, neutron scattering and ab initio quantum-mechanical molecular dynamics simulation

The Gibbs-Thomson effect modifies the pressure and temperature at which clathrates occur, hence altering the depth at which they occur in the seabed. Nuclear magnetic resonance (NMR) measurements as a function of temperature are being conducted for water/ice/ hydrate systems in a range of pore geometries, including templated SBA-15 silicas, controlled pore glasses and sol-gel silicas. Rotator-phase plastic ice is shown to be present in confined geometry, and bulk tetrahydrofuran hydrate is also shown to probably have a rotator phase. A novel NMR cryoporometry protocol, which probes both melting and freezing events while avoiding the usual problem of supercooling for the freezing event, has been developed. This enables a detailed probing of the system for a given pore size and geometry and the exploration of differences between hydrate formation and dissociation processes inside pores. These process differences have an important effect on the environment, as they impact on the ability of a marine hydrate system to re-form once warmed above a critical temperature. Ab initio quantum-mechanical molecular dynamics calculations are also being employed to probe the dynamics of liquids in pores at nanometric dimensions

Comparison of the phase diagram of the half-filled layered organic superconductors with the phase diagram of the RVB theory of the Hubbard-Heisenberg model

We present an resonating valence bond (RVB) theory of superconductivity for the Hubbard--Heisenberg model on an anisotropic triangular lattice. We show that these calculations are consistent with the observed phase diagram of the half-filled layered organic superconductors, such as the beta, beta', kappa and lambda phases of (BEDT-TTF)_2X [bis(ethylenedithio)tetrathiafulvalene] and (BETS)_2X [bis(ethylenedithio)tetraselenafulvalene]. We find a first order transition from a Mott insulator to a d_{x^2-y^2} superconductor with a small superfluid stiffness and a pseudogap with d_{x^2-y^2} symmetry. The Mott--Hubbard transition can be driven either by increasing the on-site Coulomb repulsion, U, or by changing the anisotropy of the two hopping integrals, t'/t. Our results suggest that the ratio t'/t plays an important role in determining the phase diagram of the organic superconductors.Comment: 4 pages, 3 figur

Anomalous Excitation Spectra of Frustrated Quantum Antiferromagnets

We use series expansions to study the excitation spectra of spin-1/2 antiferromagnets on anisotropic triangular lattices. For the isotropic triangular lattice model (TLM) the high-energy spectra show several anomalous features that differ strongly from linear spin-wave theory (LSWT). Even in the Neel phase, the deviations from LSWT increase sharply with frustration, leading to roton-like minima at special wavevectors. We argue that these results can be interpreted naturally in a spinon language, and provide an explanation for the previously observed anomalous finite-temperature properties of the TLM. In the coupled-chains limit, quantum renormalizations strongly enhance the one-dimensionality of the spectra, in agreement with experiments on Cs_2CuCl_4.Comment: 4 pages, 5 figures. New Fig. 3 with higher-order series data, paper shortened, references updated, one added (Ref. 28), minor changes otherwise. Published versio

Convicts and coolies : rethinking indentured labour in the nineteenth century

This article seeks to shift the frame of analysis within which discussions of Indian indentured migration take place. It argues that colonial discourses and practices of indenture are best understood not with regard to the common historiographical framework of whether it was 'a new system of slavery', but in the context of colonial innovations in incarceration and confinement. The article shows how Indian experiences of and knowledge about transportation overseas to penal settlements informed in important ways both their own understandings and representations of migration and the colonial practices associated with the recruitment of indentured labour. In detailing the connections between two supposedly different labour regimes, it thus brings a further layer of complexity to debates around their supposed distinctions

Magnetic-field-induced superconductivity in layered organic molecular crystals with localized magnetic moments

The synthetic organic compound lambda-(BETS)2FeCl4 undergoes successive transitions from an antiferromagnetic insulator to a metal and then to a superconductor as a magnetic field is increased. We use a Hubbard-Kondo model to clarify the role of the Fe(3+) magnetic ions in these phase transitions. In the high-field regime, the magnetic field acting on the electron spins is compensated by the exchange field He due to the magnetic ions. This suggests that the field-induced superconducting state is the same as the zero-field superconducting state which occurs under pressure or when the Fe(3+) ions are replaced by non-magnetic Ga(3+) ions. We show how He can be extracted from the observed splitting of the Shubnikov-de Haas frequencies. Furthermore, we use this method of extracting He to predict the field range for field-induced superconductivity in other materials.Comment: 5 page

A Note On R-Parity Violation and Fermion Masses

We consider a class of supersymmetric SU(3)\times SU(2)\times U(1) multihiggs models in which R-parity is violated through bilinear Higgs-lepton interactions. The required, due to R-parity violation, higgs-lepton rotations introduce an alternative way to generate the phenomenologically desirable fermion mass matrix structures independently of the equality of Yukawas, possibly imposed by superstring or other unification.Comment: 8 pages, uses LaTeX2

Implementing Pharmacy Informatics in College Curricula: The AACP Technology in Pharmacy Education and Learning Special Interest Group

Many professional organizations have initiatives to increase the awareness and use of informatics in the practice of pharmacy. Within education we must respond to these initiatives and make technology integral to all aspects of the curriculum, inculcating in students the importance of technology in practice. This document proposes 5 central domains for organizing planning related to informatics and technology within pharmacy education. The document is intended to encourage discussion of informatics within pharmacy education and the implications of informatics in future pharmacy practice, and to guide colleges of pharmacy in identifying and analyzing informatics topics to be taught and methods of instruction to be used within the doctor of pharmacy curriculum

Nursing teamwork in the care of older people: A mixed methods study

Healthcare is increasingly complex and requires the ability to adapt to changing demands. Teamwork is essential to delivering high quality care and is central to nursing. The aims of this study were to identify the processes that underpin nursing teamwork and how these affect the care of older people, identify the relationship between perceived teamwork and perceived quality of care, and explore in depth the experience of working in nursing teams. The study was carried out in three older people's wards in a London teaching hospital. Nurses and healthcare assistants completed questionnaires (n=65) on known dynamics of teamwork (using the Nursing Teamwork Survey) together with ratings of organisational quality (using an adapted AHRQ HSPS scale). A sample (n=22; 34%) was then interviewed about their perceptions of care, teamwork and how good outcomes are delivered in everyday work. Results showed that many care difficulties were routinely encountered, and confirmed the importance of teamwork (e.g. shared mental models of tasks and team roles and responsibilities, supported by leadership) in adapting to challenges. Perceived quality of teamwork was positively related to perceived quality of care. Work system variability and the external environment influenced teamwork, and confirmed the importance of team adaptive capacity. The CARE model shows the centrality of teamwork in adapting to variable demand and capacity to deliver care processes, and the influence of broader system factors on teamworking

The Heisenberg antiferromagnet on an anisotropic triangular lattice: linear spin-wave theory

We consider the effect of quantum spin fluctuations on the ground state properties of the Heisenberg antiferromagnet on an anisotropic triangular lattice using linear spin-wave theory. This model should describe the magnetic properties of the insulating phase of the kappa-(BEDT-TTF)_2 X family of superconducting molecular crystals. The ground state energy, the staggered magnetization, magnon excitation spectra and spin-wave velocities are computed as a function of the ratio between the second and first neighbours, J2/J1. We find that near J2/J1 = 0.5, i.e., in the region where the classical spin configuration changes from a Neel ordered phase to a spiral phase, the staggered magnetization vanishes, suggesting the possibility of a quantum disordered state. In this region, the quantum correction to the magnetization is large but finite. This is in contrast to the frustrated Heisenberg model on a square lattice, for which the quantum correction diverges logarithmically at the transition from the Neel to the collinear phase. For large J2/J1, the model becomes a set of chains with frustrated interchain coupling. For J2 > 4 J1, the quantum correction to the magnetization, within LSW, becomes comparable to the classical magnetization, suggesting the possibility of a quantum disordered state. We show that, in this regime, quantum fluctuations are much larger than for a set of weakly coupled chains with non-frustated interchain coupling.Comment: 10 pages, RevTeX + epsf, 5 figures Replaced with published version. Comparison to series expansions energies include