Thermally activated escape rates of uniaxial spin systems with transverse field

Classical escape rates of uniaxial spin systems are characterized by a prefactor differing from and much smaller than that of the particle problem, since the maximum of the spin energy is attained everywhere on the line of constant latitude: theta=const, 0 =< phi =< 2*pi. If a transverse field is applied, a saddle point of the energy is formed, and high, moderate, and low damping regimes (similar to those for particles) appear. Here we present the first analytical and numerical study of crossovers between the uniaxial and other regimes for spin systems. It is shown that there is one HD-Uniaxial crossover, whereas at low damping the uniaxial and LD regimes are separated by two crossovers.Comment: 4 PR pages, 3 figures, final published versio

LB01: Cell Salvage during Caesarean Section: A Randomised Controlled Trial (The SALVO Trial)

Objective Excessive haemorrhage at caesarean section requires the use of donor (allogeneic) blood transfusion. The SALVO trial assessed whether the routine use of cell salvage during caesarean section can reduce the need for donor blood transfusion. Study Design We conducted a randomised controlled trial (26 UK obstetric units; June 2013 through April 2016) of routine cell salvage use (intervention) vs. current standard of care without routine salvage use (control) in caesarean section among women at risk of haemorrhage. We used multivariable models, adjusting for stratification variables and prognostic factors identified a priori, to compare rates of donor blood transfusion (primary outcome) and fetomaternal haemorrhage ≥2ml in RhD-negative women with RhD-positive baby (one of the secondary outcomes) between groups. Results Of 3028 women randomised, 2990 were analysed (after exclusions for vaginal delivery or hospital transfer after randomisation). Of 1498 assigned to intervention, 95.6% had cell salvage deployed (50.8% had salvaged blood returned; mean 259.9 ml) vs. 3.9% of 1492 assigned to control. Donor blood transfusion rates were lower in the intervention group than in control (2.5% vs. 3.5%, adjusted odds ratio [OR] 0.65, 95% confidence interval [CI] 0.42 to 1.01). No case of amniotic fluid embolism was observed. Fetomaternal haemorrhage was higher with intervention vs. control (25.6% vs. 10.5%, adjusted OR 5.63, 95% CI 1.43 to 22.14). Conclusion There was modest evidence for an effect of routine use of cell salvage during caesarean section on donor blood transfusion. The increased fetomaternal haemorrhage emphasises the need for adherence to guidance on anti-D prophylaxis and for research on risks of alloimmunisation to RhD and other red cell antigens following cell salvage. (Funder: UK National Institute of Health Research Health Technology Assessment programme, ISRCTN66118656)

Quantum-Classical Transition of the Escape Rate of a Uniaxial Spin System in an Arbitrarily Directed Field

The escape rate \Gamma of the large-spin model described by the Hamiltonian H = -DS_z^2 - H_zS_z - H_xS_x is investigated with the help of the mapping onto a particle moving in a double-well potential U(x). The transition-state method yields $\Gamma$ in the moderate-damping case as a Boltzmann average of the quantum transition probabilities. We have shown that the transition from the classical to quantum regimes with lowering temperature is of the first order (d\Gamma/dT discontinuous at the transition temperature T_0) for h_x below the phase boundary line h_x=h_{xc}(h_z), where h_{x,z}\equiv H_{x,z}/(2SD), and of the second order above this line. In the unbiased case (H_z=0) the result is h_{xc}(0)=1/4, i.e., one fourth of the metastability boundary h_{xm}=1, at which the barrier disappears. In the strongly biased limit \delta\equiv 1-h_z << 1, one has h_{xc} \cong (2/3)^{3/4}(\sqrt{3}-\sqrt{2})\delta^{3/2}\cong 0.2345 \delta^{3/2}, which is about one half of the boundary value h_{xm} \cong (2\delta/3)^{3/2} \cong 0.5443 \delta^{3/2}.The latter case is relevant for experiments on small magnetic particles, where the barrier should be lowered to achieve measurable quantum escape rates.Comment: 17 PR pages, 16 figures; published versio

A novel albumin gene mutation (R222I) in familial dysalbuminemic hyperthyroxinemia

Context: Familial dysalbuminemic hyperthyroxinemia, characterized by abnormal circulating albuminwith increased T4 affinity, causes artefactual elevation of free T4 concentrations in euthyroid individuals. Objective: Four unrelated index cases with discordant thyroid function tests in different assay platforms were investigated. Design and Results: Laboratory biochemical assessment, radiolabeled T4 binding studies, and ALB sequencing were undertaken. 125I-T4 binding to both serum and albumin in affected individuals was markedly increased, comparable with known familial dysalbuminemic hyperthyroxinemia cases. Sequencing showed heterozygosity for a novel ALB mutation (arginine to isoleucine at codon 222, R222I) in all four cases and segregation of the genetic defect with abnormal biochemical phenotype in one family. Molecular modeling indicates that arginine 222 is located within a high-affinity T4 binding site in albumin, with substitution by isoleucine, which has a smaller side chain predicted to reduce steric hindrance, thereby facilitating T 4 and rT3 binding. When tested in current immunoassays, serum free T4 values from R222I heterozygotes were more measurably abnormal in one-step vs two-step assay architectures. Total rT3 measurements were also abnormally elevated. Conclusions: A novel mutation (R222I) in the ALB gene mediates dominantly inherited dysalbuminemic hyperthyroxinemia. Susceptibility of current free T4 immunoassays to interference by this mutant albumin suggests likely future identification of individuals with this variant binding protein

Interface localisation-delocalisation transition in a symmetric polymer blend: a finite-size scaling Monte Carlo study

Using extensive Monte Carlo simulations we study the phase diagram of a symmetric binary (AB) polymer blend confined into a thin film as a function of the film thickness D. The monomer-wall interactions are short ranged and antisymmetric, i.e, the left wall attracts the A-component of the mixture with the same strength as the right wall the B-component, and give rise to a first order wetting transition in a semi-infinite geometry. The phase diagram and the crossover between different critical behaviors is explored. For large film thicknesses we find a first order interface localisation/delocalisation transition and the phase diagram comprises two critical points, which are the finite film width analogies of the prewetting critical point. Using finite size scaling techniques we locate these critical points and present evidence of 2D Ising critical behavior. When we reduce the film width the two critical points approach the symmetry axis $\phi=1/2$ of the phase diagram and for $D \approx 2 R_g$ we encounter a tricritical point. For even smaller film thickness the interface localisation/delocalisation transition is second order and we find a single critical point at $\phi=1/2$. Measuring the probability distribution of the interface position we determine the effective interaction between the wall and the interface. This effective interface potential depends on the lateral system size even away from the critical points. Its system size dependence stems from the large but finite correlation length of capillary waves. This finding gives direct evidence for a renormalization of the interface potential by capillary waves in the framework of a microscopic model.Comment: Phys.Rev.

Mapping policies and programmes: the use of GIS to communicate spatial relationships in England

It has long been acknowledged that there is a gap between the advancement of GIS in the research field and its application in planning practice. This paper demonstrates the potential for employing simple GIS mapping overlays as a way of communicating complex planning issues in a ‘language’ that is easily understandable and effective at stimulating policy debate, critical thinking and learning. The analysis focuses on capturing the synergies and conflicts in two key planning challenges in England, progrowth and housing delivery agendas. In a political context where spatial evidencebased policymaking has been eroded in recent years, the analysis demonstrates the need for policymakers to ‘think spatially, act spatially’ when developing different policies and programmes. The paper concludes that only by making spatial relationships of policies and programmes explicit in a manner that is easily understood by a range of actors, can different spatial scenarios and metaphors of future opportunities and challenges be developed to inform long-range development and planning

Characteristics and drivers of forest cover change in the post-socialist era in Croatia: evidence from a mixed-methods approach

© 2016, Springer-Verlag Berlin Heidelberg.Extensive forests in Croatia represent an important biological and economic resource in Europe. They are characterised by heterogeneity in forest management practices dating back to the socialist planned economy of the pre-1991 era. In this study we investigated the difference in rates of deforestation and reforestation in private- and state-owned forests during the post-socialist period and the causal drivers of change. The selected region of Northern Croatia is characterised by a high percentage of privately owned forests with minimal national monitoring and control. We used a mixed-methods approach which combines remote sensing, statistical modelling and a household-based questionnaire survey to assess the rates of forest cover change and factors influencing those changes. The results show that predominantly privately owned forests in Northern Croatia have recorded a net forest loss of 1.8 % during the 1991–2011 period, while Croatia overall is characterised by a 10 % forest cover increase in predominantly state-owned forests. Main factors influencing forest cover changes in private forests are slope, altitude, education structure, population age and population density. The results also show that the deforestation in private forests is weakening overall, mostly due to the continuation of the de-agrarisation and de-ruralisation processes which began during socialism

A feasibility study investigating the acceptability and design of a multicentre randomised controlled trial of needle fasciotomy versus limited fasciectomy for the treatment of Dupuytren’s contractures of the fingers (HAND-1): study protocol for a randomised controlled trial

Background Dupuytren’s contractures are fibrous cords under the skin of the palm of the hand. The contractures are painless but cause one or more fingers to curl into the palm, resulting in loss of function. Standard treatment within the NHS is surgery to remove (fasciectomy) or divide (fasciotomy) the contractures, and the treatment offered is frequently determined by surgeon preference. This study aims to determine the feasibility of conducting a large, multicentre randomised controlled trial to assess the clinical and cost-effectiveness of needle fasciotomy versus limited fasciectomy for the treatment of Dupuytren’s contracture. Methods/design HAND-1 is a parallel, two-arm, multicentre, randomised feasibility trial. Eligible patients aged 18 years or over who have one or more fingers with a Dupuytren’s contracture of more than 30° in the metacarpophalangeal (MCP) and/or proximal interphalangeal (PIP) joints, well-defined cord(s) causing contracture, and have not undergone previous surgery for Dupuytren’s on the same hand will be randomised (1:1) to treatment with either needle fasciotomy or limited fasciectomy. Participants will be followed-up for up to 6 months post surgery. Feasibility outcomes include number of patients screened, consented and randomised, adherence with treatment, completion of follow-up and identification of an appropriate patient-reported outcome measure (PROM) to use as primary outcome for a main trial. Embedded qualitative research, incorporating a QuinteT Recruitment Intervention, will focus on understanding and optimising the recruitment process, and exploring patients’ experiences of trial participation and the interventions. Discussion This study will assess whether a large multicentre trial comparing the clinical and cost-effectiveness of needle fasciotomy and limited fasciectomy for the treatment of Dupuytren’s contractures is feasible, and if so will provide data to inform its design and successful conduct