On the Construction of Trigonometric Solutions of the Yang-Baxter Equation

We describe the construction of trigonometric R-matrices corresponding to the (multiplicity-free) tensor product of any two irreducible representations of a quantum algebra U_q(\G). Our method is a generalization of the tensor product graph method to the case of two different representations. It yields the decomposition of the R-matrix into projection operators. Many new examples of trigonometric R-matrices (solutions to the spectral parameter dependent Yang-Baxter equation) are constructed using this approach.Comment: latex file, 29 pages, Universitaet Bielefeld and University of Queensland preprint, BI-TP-94/13, UQMATH-94-02 (minor correction: in eq. (4.63) the number 32 should be replaced by 36 and in eq. (4.64) -16 becomes -18 and -10 becomes -8.

The R-matrix of the U_q(d_4(3)) algebra and g_2(1) affine Toda field theory

The R-matrix of the U_q(d_4(3)) algebra is constructed in the 8-dimensional fundamental representation. Using this result an exact S-matrix is conjectured for the imaginary coupled g_2(1) affine Toda field theory, the structure of which is found to be very similar to the previously investigated S-matrix of d_4(3) Toda theory. It is shown that this S-matrix is consistent with the results for the case of real coupling using the breather-particle correspondence. For q a root of unity it is argued that the theory can be restricted to yield Phi(11|12) perturbations of WA_2 minimal models.Comment: 18 pages, LaTeX file. Some comments added, typos and mistakes in the references are corrected. Problems with Postscript generation are fixe

Development and initial validation of the bronchiectasis exacerbation and symptom tool (BEST)

BACKGROUND: Recurrent bronchiectasis exacerbations are related to deterioration of lung function, progression of the disease, impairment of quality of life, and to an increased mortality. Improved detection of exacerbations has been accomplished in chronic obstructive pulmonary disease through the use of patient completed diaries. These tools may enhance exacerbation reporting and identification. The aim of this study was to develop a novel symptom diary for bronchiectasis symptom burden and detection of exacerbations, named the BEST diary. METHODS: Prospective observational study of patients with bronchiectasis conducted at Ninewells Hospital, Dundee. We included patients with confirmed bronchiectasis by computed tomography, who were symptomatic and had at least 1 documented exacerbation of bronchiectasis in the previous 12\u2009months to participate. Symptoms were recorded daily in a diary incorporating cough, sputum volume, sputum colour, dyspnoea, fatigue and systemic disturbance scored from 0 to 26. RESULTS: Twenty-one patients were included in the study. We identified 29 reported (treated exacerbations) and 23 unreported (untreated) exacerbations over 6-month follow-up. The BEST diary score showed a good correlation with the established and validated questionnaires and measures of health status (COPD Assessment Test, r =\u20090.61, p =\u20090.0037, Leicester Cough Questionnaire, r =\u2009-\u20090.52,p =\u20090.0015, St Georges Respiratory Questionnaire, r =\u20090.61,p <\u20090.0001 and 6\u2009min walk test, r =\u2009-\u20090.46,p =\u20090.037). The mean BEST score at baseline was 7.1 points (SD 2.2). The peak symptom score during exacerbation was a mean of 16.4 (3.1), and the change from baseline to exacerbation was a mean of 9.1 points (SD 2.5). Mean duration of exacerbations based on time for a return to baseline symptoms was 15.3\u2009days (SD 5.7). A minimum clinically important difference of 4 points is proposed. CONCLUSIONS: The BEST symptom diary has shown concurrent validity with current health questionnaires and is responsive at onset and recovery from exacerbation. The BEST diary may be useful to detect and characterise exacerbations in bronchiectasis clinical trials

Impact of Scottish smoke-free legislation on smoking quit attempts and prevalence

<p><b>Objectives:</b> In Scotland, legislation was implemented in March 2006 prohibiting smoking in all wholly or partially enclosed public spaces. We investigated the impact on attempts to quit smoking and smoking prevalence.</p> <p><b>Methods:</b> We performed time series models using Box-Jenkins autoregressive integrated moving averages (ARIMA) on monthly data on the gross ingredient cost of all nicotine replacement therapy (NRT) prescribed in Scotland in 2003–2009, and quarterly data on self-reported smoking prevalence between January 1999 and September 2010 from the Scottish Household Survey.</p> <p><b>Results:</b> NRT prescription costs were significantly higher than expected over the three months prior to implementation of the legislation. Prescription costs peaked at £1.3 million in March 2006; £292,005.9 (95% CI £260,402.3, £323,609, p<0.001) higher than the monthly norm. Following implementation of the legislation, costs fell exponentially by around 26% per month (95% CI 17%, 35%, p<0.001). Twelve months following implementation, the costs were not significantly different to monthly norms. Smoking prevalence fell by 8.0% overall, from 31.3% in January 1999 to 23.7% in July–September 2010. In the quarter prior to implementation of the legislation, smoking prevalence fell by 1.7% (95% CI 2.4%, 1.0%, p<0.001) more than expected from the underlying trend.</p> <p><b>Conclusions:</b> Quit attempts increased in the three months leading up to Scotland's smoke-free legislation, resulting in a fall in smoking prevalence. However, neither has been sustained suggesting the need for additional tobacco control measures and ongoing support.</p&gt

Subdivision of the bacterioferritin comigratory protein family of bacterial peroxiredoxins based on catalytic activity.

© American Chemical Society,2010. Post-print version of article deposited in accordance with SHERPA RoMEO guidelinesPeroxiredoxins are ubiquitous proteins that catalyze the reduction of hydroperoxides, thus conferring resistance to oxidative stress. Using high-resolution mass spectrometry, we recently reclassified one such peroxiredoxin, bacterioferritin comigratory protein (BCP) of Escherichia coli, as an atypical 2-Cys peroxiredoxin that functions through the formation of an intramolecular disulfide bond between the active and resolving cysteine. An engineered E. coli BCP, which lacked the resolving cysteine, retained enzyme activity through a novel catalytic pathway. Unlike the active cysteine, the resolving cysteine of BCP peroxiredoxins is not conserved across all members of the family. To clarify the catalytic mechanism of native BCP enzymes that lack the resolving cysteine, we have investigated the BCP homologue of Burkholderia cenocepacia. We demonstrate that the B. cenocepacia BCP (BcBCP) homologue functions through a 1-Cys catalytic pathway. During catalysis, BcBCP can utilize thioredoxin as a reductant for the sulfenic acid intermediate. However, significantly higher peroxidase activity is observed utilizing glutathione as a resolving cysteine and glutaredoxin as a redox partner. Introduction of a resolving cysteine into BcBCP changes the activity from a 1-Cys pathway to an atypical 2-Cys pathway, analogous to the E. coli enzyme. In contrast to the native B. cenocepacia enzyme, thioredoxin is the preferred redox partner for this atypical 2-Cys variant. BCP-deficient B. cenocepacia exhibit a growth-phase-dependent hypersensitivity to oxidative killing. On the basis of sequence alignments, we believe that BcBCP described herein is representative of the major class of bacterial BCP peroxiredoxins. To our knowledge, this is the first detailed characterization of their catalytic activity. These studies support the subdivision of the BCP family of peroxiredoxins into two classes based on their catalytic activity

Aggregates of Chemically Functionalized Multiwalled Carbon Nanotubes as Viscosity Reducers

Confinement and surface effects provided by nanoparticles have been shown to produce changes in polymer molecules affecting their macroscopic viscosity. Nanoparticles may induce rearrangements in polymer conformation with an increase in free volume significantly lowering the viscosity. This phenomenon is generally attributed to the selective adsorption of the polymer high molar mass fraction onto nanoparticles surface when the polymer radius of gyration is comparable to the nanoparticles characteristic dimensions. Carbon nanotubes seem to be the ideal candidate to induce viscosity reduction of polymer due to both their high surface-to-volume ratio and their nanometric sizes, comparable to the gyration radius of polymer chains. However, the amount of nanotube in a polymer system is limited by the percolation threshold as, above this limit, the formation of a nanotubes network hinders the viscosity reduction effect. Based on these findings, we have used multiwalled carbon nanotubes MWCNT “aggregates” as viscosity reducers. Our results reveal both that the use of nanotube clusters reduce significantly the viscosity of the final system and strongly increase the nanotube limiting concentration for viscosity hindering. By using hydroxyl and carboxyl functionalized nanotubes, this effect has been rather maximized likely due to the hydrogen bridged stabilization of nanotube aggregates

Single atom quantum walk with 1D optical superlattices

A proposal for the implementation of quantum walks using cold atom technology is presented. It consists of one atom trapped in time varying optical superlattices. The required elements are presented in detail including the preparation procedure, the manipulation required for the quantum walk evolution and the final measurement. These procedures can be, in principle, implemented with present technology.Comment: 6 pages, 7 figure

Photospheric flux cancellation and associated flux rope formation and eruption

We study an evolving bipolar active region that exhibits flux cancellation at the internal polarity inversion line, the formation of a soft X-ray sigmoid along the inversion line and a coronal mass ejection. The evolution of the photospheric magnetic field is described and used to estimate how much flux is reconnected into the flux rope. About one third of the active region flux cancels at the internal polarity inversion line in the 2.5~days leading up to the eruption. In this period, the coronal structure evolves from a weakly to a highly sheared arcade and then to a sigmoid that crosses the inversion line in the inverse direction. These properties suggest that a flux rope has formed prior to the eruption. The amount of cancellation implies that up to 60% of the active region flux could be in the body of the flux rope. We point out that only part of the cancellation contributes to the flux in the rope if the arcade is only weakly sheared, as in the first part of the evolution. This reduces the estimated flux in the rope to $\sim\!30$ or less of the active region flux. We suggest that the remaining discrepancy between our estimate and the limiting value of $\sim\!10$ of the active region flux, obtained previously by the flux rope insertion method, results from the incomplete coherence of the flux rope, due to nonuniform cancellation along the polarity inversion line. A hot linear feature is observed in the active region which rises as part of the eruption and then likely traces out field lines close to the axis of the flux rope. The flux cancellation and changing magnetic connections at one end of this feature suggest that the flux rope reaches coherence by reconnection shortly before and early in the impulsive phase of the associated flare. The sigmoid is destroyed in the eruption but reforms within a few hours after a moderate amount of further cancellation has occurred.Comment: Astron. Astrophys., in pres