Fungal specificity bottlenecks during orchid germination and development.

Published versio

Open windrow composting of polymers: An investigation into the rate of degradation of polyethylene

The compostability of degradable polymers under open windrow composting conditions is explored within this paper. Areas for consideration were the use of, and impacts of, degradable polyethylene (PE) sacks on the composting process and the quality of the finished compost product. These factors were investigated through polymer weight loss over the composting process, the amount of polymer residue and chemical contaminants in the finished compost product, the windrow temperature profiles and a bioassay to establish plant growth and germination levels using the final compost product. This trial also included a comparative study of the weight loss under composting conditions of two different types of ‘degradable’ polymer sacks currently on the European market: PE and a starch based product. Statistical analysis of the windrow temperature profiles has led to the development of a model, which can help to predict the expected trends in the temperature profiles of open compost windrows where the organic waste is kerbside collected using a degradable PE sack

A Stochastic Finite Element Model for the Dynamics of Globular Macromolecules

We describe a novel coarse grained simulation method for modelling the dynamics of globular macromolecules, such as proteins. The macromolecule is treated as a viscoelastic continuum that is subject to thermal fluctuations. The model includes a non-linear treatment of elasticity and viscosity with thermal noise that is solved using finite element analysis. We have validated the method by demonstrating that the model provides average kinetic and potential energies that are in agreement with the classical equipartition theorem. In addition, we have performed Fourier analysis on the simulation trajectories obtained for a series of linear beams to confirm that the correct average energies are present in the first two Fourier bending modes. We have then used the new modelling method to simulate the thermal fluctuations of a representative protein over 500ns timescales. Using reasonable parameters for the material properties, we have demonstrated that the overall deformation of the biomolecule is consistent with the results obtained for proteins in general from atomistic molecular dynamics simulations

The relationship between perfectionistic self-presentation and reactions to impairment and disability following spinal cord injury

Univariate and multivariate relationships between perfectionistic self-presentation and reactions to impairment and disability following spinal cord injury were examined. One hundred and forty-four adults with spinal cord injury (M = 48.18 years, SD = 15.96) completed self-report measures. Analyses revealed that, after controlling for time since injury and gender, perfectionistic self-presentation predicted six of eight reactions, shock, depression, and internalised anger particularly strongly. In addition, at multivariate level, perfectionistic self-presentation was positively related to non-adaptive reactions and negatively related to adaptive reactions. The findings suggest that perfectionistic self-presentation may contribute to poorer psychosocial adaptation to spinal cord injury

Modeling of synthesis and flow properties of propylene-diene copolymers

Copolymerization with nonconjugated dienes offers an attractive route for introducing long-chain branching in polypropylene. From a simplified set of rate equations for such copolymerization with a metallocene catalyst, we derive the probabilities of branch formation at different stages of the reaction in a semibatch reactor. Using these probabilities, we generate an ensemble of molecules via a Monte Carlo sampling. The knowledge of the branching topology and segment lengths allows us to compute the flow properties of the resins from computational rheology. We compare our model predictions with existing experimental data, namely the molar mass distribution and small amplitude oscillatory shear response, for a set of resins with varying diene content. The rheology data suggest that the entanglement time Ï.,e depends sensitively and in a well-defined fashion on the diene content

Modifying the pom-pom model for extensional viscosity overshoots

We have developed a variant of the pom-pom model that qualitatively describes two surprising features recently observed in filament stretching rheometer experiments of uniaxial extensional flow of industrial branched polymer resins: (i) Overshoots of the transient stress during steady flow and (ii) strongly accelerated stress relaxation upon cessation of the flow beyond the overshoot. Within the context of our model, these overshoots originate from entanglement stripping (ES) during the processes of normal chain retraction and branch point withdrawal. We demonstrate that, for a single mode, the predictions of our overshoot model are qualitatively consistent with experimental data. To provide a quantitative fit, we represent an industrial melt by a superposition of several individual modes. We show that a minimal version of our model, in which ES due to normal chain retraction is omitted, can provide a reasonable, but not perfect, fit to the data. With regard the stress relaxation after (kinematically) steady flow, we demonstrate that the differential version of tube orientation dynamics in the original pom-pom model performs anomalously. We discuss the reasons for this and suggest a suitable alternative

Rotavirus vaccine impact and socioeconomic deprivation: an interrupted time-series analysis of gastrointestinal disease outcomes across primary and secondary care in the UK.

Background Rotavirus causes severe gastroenteritis in infants and young children worldwide. The UK introduced the monovalent rotavirus vaccine (Rotarix®) in July 2013. Vaccination is free of charge to parents, with two doses delivered at 8 and 12 weeks of age. We evaluated vaccine impact across a health system in relation to socioeconomic deprivation. Methods We used interrupted time-series analyses to assess changes in monthly health-care attendances in Merseyside, UK, for all ages, from July 2013 to June 2016, compared to predicted counterfactual attendances without vaccination spanning 3–11 years pre-vaccine. Outcome measures included laboratory-confirmed rotavirus gastroenteritis (RVGE) hospitalisations, acute gastroenteritis (AGE) hospitalisations, emergency department (ED) attendances for gastrointestinal conditions and consultations for infectious gastroenteritis at community walk-in centres (WIC) and general practices (GP). All analyses were stratified by age. Hospitalisations were additionally stratified by vaccine uptake and small-area-level socioeconomic deprivation. Results The uptake of the first and second doses of rotavirus vaccine was 91.4% (29,108/31,836) and 86.7% (27,594/31,836), respectively. Among children aged < 5 years, the incidence of gastrointestinal disease decreased across all outcomes post-vaccine introduction: 80% (95% confidence interval [CI] 70–87%; p < 0.001) for RVGE hospitalisation, 44% (95% CI 35–53%; p < 0.001) for AGE hospitalisations, 23% (95% CI 11–33%; p < 0.001) for ED, 32% (95% CI 7–50%; p = 0.02) for WIC and 13% (95% CI -3–26%; p = 0.10) for GP. The impact was greatest during the rotavirus season and for vaccine-eligible age groups. In adults aged 65+ years, AGE hospitalisations fell by 25% (95% CI 19–30%; p < 0.001). The pre-vaccine risk of AGE hospitalisation was highest in the most socioeconomically deprived communities (adjusted incident rate ratio 1.57; 95% CI 1.51–1.64; p < 0.001), as was the risk for non-vaccination (adjusted risk ratio 1.54; 95% CI 1.34–1.75; p < 0.001). The rate of AGE hospitalisations averted per 1,000 first doses of vaccine was higher among infants in the most deprived communities compared to the least deprived in 2014/15 (28; 95% CI 25–31 vs. 15; 95% CI 12–17) and in 2015/16 (26; 95% CI 23–30 vs. 13; 95% CI 11–16). Conclusions Following the introduction of rotavirus vaccination, incidence of gastrointestinal disease reduced across the health-care system. Vaccine impact was greatest among the most deprived populations, despite lower vaccine uptake. Prioritising vaccine uptake in socioeconomically deprived communities should give the greatest health benefit in terms of population disease burden

Heavy electrons and the symplectic symmetry of spin

The recent discovery of two heavy fermion materials PuCoGa_{5} and NpPd_{5}Al_{2} which transform directly from Curie paramagnets into superconductors, reveals a new class of superconductor where local moments quench directly into a superconducting condensate. A powerful tool in the description of heavy fermion metals is the large N expansion, which expands the physics in powers of 1/N about a solvable limit where particles carry a large number (N) of spin components. As it stands, this method is unable to jointly describe the spin quenching and superconductivity which develop in PuCoGa_{5} and NpPd_{5}Al_{2}. Here, we solve this problem with a new class of large N expansion that employs the symplectic symmetry of spin to protect the odd time-reversal parity of spin and sustain Cooper pairs as well-defined singlets. With this method we show that when a lattice of magnetic ions exchange spin with their metallic environment in two distinct symmetry channels, they are able to simultaneously satisfy both channels by forming a condensate of composite pairs between between local moments and electrons. In the tetragonal crystalline environment relevant to PuCoGa_{5} and NpPd_{5}Al_{2} the lattice structure selects a natural pair of spin exchange channels, giving rise to the prediction of a unique anisotropic paired state with g-wave symmetry. This pairing mechanism predicts a large upturn in the NMR relaxation rate above T_{c}, a strong enhancement of Andreev reflection in tunneling measurements and an enhanced superconducting transition temperature T_{c} in Pu doped Np_{1-x}Pu_{x}Pd_{5}Al_{2}.Comment: This is a substantially revised version of the original paper, focussing on the high temperature heavy electron superconductors PuCoGa_5 and NpPd_5Al_2. A substantially revised supplementary online material to this paper can be found in arXiv 0710.1128v

Composite Fermion Metals from Dyon Black Holes and S-Duality

We propose that string theory in the background of dyon black holes in four-dimensional anti-de Sitter spacetime is holographic dual to conformally invariant composite Dirac fermion metal. By utilizing S-duality map, we show that thermodynamic and transport properties of the black hole match with those of composite fermion metal, exhibiting Fermi liquid-like. Built upon Dirac-Schwinger-Zwanziger quantization condition, we argue that turning on magnetic charges to electric black hole along the orbit of Gamma(2) subgroup of SL(2,Z) is equivalent to attaching even unit of statistical flux quanta to constituent fermions. Being at metallic point, the statistical magnetic flux is interlocked to the background magnetic field. We find supporting evidences for proposed holographic duality from study of internal energy of black hole and probe bulk fermion motion in black hole background. They show good agreement with ground-state energy of composite fermion metal in Thomas-Fermi approximation and cyclotron motion of a constituent or composite fermion excitation near Fermi-point.Comment: 30 pages, v2. 1 figure added, minor typos corrected; v3. revised version to be published in JHE

Early impact of rotavirus vaccination in a large paediatric hospital in the UK.

The impact of routine rotavirus vaccination on community-acquired (CA) and healthcare-associated (HA) rotavirus gastroenteritis (RVGE) at a large paediatric hospital, UK, was investigated over a 13-year period. A total of 1644 hospitalized children aged 0-15 years tested positive for rotavirus between July 2002 and June 2015. Interrupted time-series analysis demonstrated that, post vaccine introduction (July 2013 to June 2015), CA- and HA-RVGE hospitalizations were 83% [95% confidence interval (CI): 72-90%) and 83% (95% CI: 66-92%] lower than expected, respectively. Rotavirus vaccination has rapidly reduced the hospital rotavirus disease burden among both CA- and HA-RVGE cases