Inference of oxygen vacancies in hydrothermal Na0.5Bi0.5TiO3

A high-resolution x-ray powder diffraction study has been made of pseudo-rhombohedral and tetragonal phases in Na0.5Bi0.5TiO3 (NBT), produced via hydrothermal and conventional solidstate methods. Hydrothermal NBT exhibits significantly greater structural distortion at room temperature than solid-state NBT. Peak widths and superstructure peak intensities show a phase transition at 305 C, with trends suggesting that the structure tends towards cubic symmetry at this temperature. Structural refinements indicate that the transition occurs via a phase coexistence region with no clear intermediate phase. Piezoelectric data show evidence of polarisation pinning in hydrothermal NBT, interpreted as a high proportion of oxygen vacancies

Six months of mass outflow and inclined rings in the ejecta of V1494 Aql

V1494 Aql was a very fast nova which reached a visual maximum of mv≃ 4.0 by the end of 1999 December 3. We report observations from 4 to 284 d after discovery, including submillimetre- and centimetre-band fluxes, a single MERLIN image and optical spectroscopy in the 410 to 700 nm range. The extent of the radio continuum emission is consistent with a recent lower distance estimate of 1.6 kpc. We conclude that the optical and radio emission arises from the same expanding ejecta. We show that these observations are not consistent with simple kinematical spherical shell models used in the past to explain the rise and fall of the radio flux density in these objects. The resolved remnant structure is consistent with an inclined ring of enhanced density within the ejecta. Optical spectroscopy indicates likely continued mass ejection for over 195 d, with the material becoming optically thin in the visible sometime between 195 and 285 d after outburst

Excited Boundary TBA in the Tricritical Ising Model

By considering the continuum scaling limit of the $A_{4}$ RSOS lattice model of Andrews-Baxter-Forrester with integrable boundaries, we derive excited state TBA equations describing the boundary flows of the tricritical Ising model. Fixing the bulk weights to their critical values, the integrable boundary weights admit a parameter $\xi$ which plays the role of the perturbing boundary field $\phi_{1,3}$ and induces the renormalization group flow between boundary fixed points. The boundary TBA equations determining the RG flows are derived in the $\mathcal{B}_{(1,2)}\to \mathcal{B}_{(2,1)}$ example. The induced map between distinct Virasoro characters of the theory are specified in terms of distribution of zeros of the double row transfer matrix.Comment: Latex, 14 pages - Talk given at the Landau meeting "CFT and Integrable Models", Sept. 2002 - v2: some statements about $\phi_{1,2}$ perturbations correcte

The in situ synthesis of PbS nanocrystals from lead(II) n -octylxanthate within a 1,3-diisopropenylbenzene–bisphenol A dimethacrylate sulfur copolymer

The synthesis of lead sulfide nanocrystals within a solution processable sulfur ‘inverse vulcanization’ polymer thin film matrix was achieved from the in situ thermal decomposition of lead(II) n-octylxanthate, [Pb(S2COOct)2]. The growth of nanocrystals within polymer thin films from single-source precursors offers a faster route to networks of nanocrystals within polymers when compared with ex situ routes. The ‘inverse vulcanization’ sulfur polymer described herein contains a hybrid linker system which demonstrates high solubility in organic solvents, allowing solution processing of the sulfur-based polymer, ideal for the formation of thin films. The process of nanocrystal synthesis within sulfur films was optimized by observing nanocrystal formation by X-ray photoelectron spectroscopy and X-ray diffraction. Examination of the film morphology by scanning electron microscopy showed that beyond a certain precursor concentration the nanocrystals formed were not only within the film but also on the surface suggesting a loading limit within the polymer. We envisage this material could be used as the basis of a new generation of materials where solution processed sulfur polymers act as an alternative to traditional polymers

Knowledge, Beliefs, and Decisions of Pregnant Australian Women Concerning Donation and Storage of Umbilical Cord Blood: A Population‐Based Survey

Background: Many women giving birth in Australian hospitals can choose to donate their child’s umbilical cord blood to a public cord blood bank or pay to store it privately. We conducted a survey to determine the proportion and characteristics of pregnant women who are aware of umbilical cord blood (UCB) banking and who have considered and decided about this option. The survey also sought to ascertain information sources, knowledge and beliefs about UCB banking, and the effect of basic information about UCB on decisions. Methods: Researchers and/or hospital maternity staff distributed a survey with basic information about UCB banking to 1,873 women of at least 24 weeks gestation who were attending antenatal classes and hospital clinics in 14 Public and private maternity hospitals in New South Wales. Results: Most respondents (70.7%) were aware of UCB banking. Their main information sources were leaflets from hospital clinics, print media, antenatal classes, TV, radio, friends and relatives. Knowledge about UCB banking was patchy, and respondents overestimated the likelihood their child would need or benefit from UCB. Women who were undecided about UCB banking were younger, less educated or from ethnic or rural backgrounds. After providing basic information about UCB banking, the proportion of respondents who indicated they had decided whether or not to donate or store UCB more than doubled from 30.0% to 67.7%. Conclusions: Basic information for parents about UCB banking can affect planned decisions about UCB banking. Information should be accurate and balanced, should counter misconceptions, and should target specific groups. Keywords: Antenatal care; Health information; Blood banks; New South Wales, AustraliaNational Health and Medical Research Council of Australia. Grant Number: 51241

High Temperature Limit of the Confining Phase

The deconfining transition in non-Abelian gauge theory is known to occur by a condensation of Wilson lines. By expanding around an appropriate Wilson line background, it is possible at large $N$ to analytically continue the confining phase to arbitrarily high temperatures, reaching a weak coupling confinement regime. This is used to study the high temperature partition function of an $SU(N)$ electric flux tube. It is found that the partition function corresponds to that of a string theory with a number of world-sheet fields that diverges at short distance.Comment: 13 page

Knowledge, Beliefs, and Decisions of Pregnant Australian Women Concerning Donation and Storage of Umbilical Cord Blood: A Population‐Based Survey

postprintBackground: Many women giving birth in Australian hospitals can choose to donate their child’s umbilical cord blood to a public cord blood bank or pay to store it privately. We conducted a survey to determine the proportion and characteristics of pregnant women who are aware of umbilical cord blood (UCB) banking and who have considered and decided about this option. The survey also sought to ascertain information sources, knowledge and beliefs about UCB banking, and the effect of basic information about UCB on decisions. Methods: Researchers and/or hospital maternity staff distributed a survey with basic information about UCB banking to 1,873 women of at least 24 weeks gestation who were attending antenatal classes and hospital clinics in 14 Public and private maternity hospitals in New South Wales. Results: Most respondents (70.7%) were aware of UCB banking. Their main information sources were leaflets from hospital clinics, print media, antenatal classes, TV, radio, friends and relatives. Knowledge about UCB banking was patchy, and respondents overestimated the likelihood their child would need or benefit from UCB. Women who were undecided about UCB banking were younger, less educated or from ethnic or rural backgrounds. After providing basic information about UCB banking, the proportion of respondents who indicated they had decided whether or not to donate or store UCB more than doubled from 30.0% to 67.7%. Conclusions: Basic information for parents about UCB banking can affect planned decisions about UCB banking. Information should be accurate and balanced, should counter misconceptions, and should target specific groups. Keywords: Antenatal care; Health information; Blood banks; New South Wales, AustraliaNational Health and Medical Research Council of Australia. Grant Number: 51241