376 research outputs found

    Frequency stabilization of DBR fiber grating laser using interferometric technique

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    Signatures of Electronic Nematic Phase at Isotropic-Nematic Phase Transition

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    The electronic nematic phase occurs when the point-group symmetry of the lattice structure is broken, due to electron-electron interactions. We study a model for the nematic phase on a square lattice with emphasis on the phase transition between isotropic and nematic phases within mean field theory. We find the transition to be first order, with dramatic changes in the Fermi surface topology accompanying the transition. Furthermore, we study the conductivity tensor and Hall constant as probes of the nematic phase and its transition. The relevance of our findings to Hall resistivity experiments in the high-TcT_c cuprates is discussed.Comment: 5 pages, 3 figure

    Client Service Receipt Inventory as a standardised tool for measurement of socio-economic costs in the rare genetic disease population (CSRI-Ra)

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    The measurement of costs is fundamental in healthcare decision-making, but it is often challenging. In particular, standardised methods have not been developed in the rare genetic disease population. A reliable and valid tool is critical for research to be locally meaningful yet internationally comparable. Herein, we sought to develop, contextualise, translate, and validate the Client Service Receipt Inventory for the RAre disease population (CSRI-Ra) to be used in cost-of-illness studies and economic evaluations for healthcare planning. Through expert panel discussions and focus group meetings involving 17 rare disease patients, carers, and healthcare and social care professionals from Hong Kong, we have developed the CSRI-Ra. Rounds of forward and backward translations were performed by bilingual researchers, and face validity and semantic equivalence were achieved through interviews and telephone communications with focus group participants and an additional of 13 healthcare professional and university students. Intra-class correlation coefficient (ICC) was used to assess criterion validity between CSRI-Ra and electronic patient record in a sample of 94 rare disease patients and carers, with overall ICC being 0.69 (95% CI 0.56–0.78), indicating moderate to good agreement. Following rounds of revision in the development, contextualisation, translation, and validation stages, the CSRI-Ra is ready for use in empirical research. The CSRI-Ra provides a sufficiently standardised yet adaptable method for collecting socio-economic data related to rare genetic diseases. This is important for near-term and long-term monitoring of the resource consequences of rare diseases, and it provides a tool for use in economic evaluations in the future, thereby helping to inform planning for efficient and effective healthcare. Adaptation of the CSRI-Ra to other populations would facilitate international research

    Vertex functions for d-wave mesons in the light-front approach

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    While the light-front quark model (LFQM) is employed to calculate hadronic transition matrix elements, the vertex functions must be pre-determined. In this work we derive the vertex functions for all d-wave states in this model. Especially, since both of 3D1^3D_1 and 3S1^3S_1 are 11^{--} mesons, the Lorentz structures of their vertex functions are the same. Thus when one needs to study the processes where 3D1^3D_1 is involved, all the corresponding formulas for 3S1^3S_1 states can be directly applied, only the coefficient of the vertex function should be replaced by that for 3D1^3D_1. The results would be useful for studying the newly observed resonances which are supposed to be d-wave mesons and furthermore the possible 2S-1D mixing in ψ\psi' with the LFQM.Comment: 12 pages, 2 figures, some typos corrected and more discussions added. Accepted by EPJ

    Estrogen receptor alpha polymorphism is associated with pelvic organ prolapse risk

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    Estrogen and estrogen receptors are known to play important roles in the pathophysiology of pelvic organ prolapse (POP). We investigated whether estrogen receptor alpha (ER alpha) gene polymorphisms were associated with POP risk by conducting a case-control association study in 88 women with POP and 153 women without POP. Genotypes of the ER alpha (ESR1) gene polymorphisms (rs17847075, rs2207647, rs2234693, rs3798577, and rs2228480) were determined by polymerase chain reaction, followed by restriction fragment length polymorphism analysis. There was significant difference between women with and those without POP in the distribution of the ESR1 rs2228480 genotypes evaluated. By using multivariable logistic regression, age and ESR1 rs2228480 genotype GA were significantly associated with POP risk. Although the sample size of women with POP studied is small, the present study shows that ER alpha genotype may be associated with POP risk

    Frequency and distance of transposition of a modified Dissociation element in transgenic tobacco

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    Effective transposon tagging with the Ac/Ds system in heterologous plant species relies on the accomplishment of a potentially high transposon-induced mutation frequency. The primary parameters that determine the mutation frequency include the transposition frequency and the transposition distance. In addition, the development of a generally applicable transposon tagging strategy requires predictable transposition behaviour. We systematically analysed Ds transposition frequencies and Ds transposition distances in tobacco. An artificial Ds element was engineered with reporter genes that allowed transposon excision and integration to be monitored visually. To analyse the variability of Ds transposition between different tobacco lines, eight single copy T-DNA transformants were selected. For trans-activation of the Ds elements, different Ac lines were used carrying an unmodified Ac+ element, an immobilized sAc element and a stable Ac element under the control of a heterologous chalcone synthase (chsA) promoter. With all Ac elements, each Ds line showed characteristic and heritable variegation patterns at the seedling level. Similar Ds line-specificity was observed for the frequency by which Ds transpositions were germinally transmitted, as well as for the distances of the Ds transpositions. The sac element induced transposition of Ds late in plant development, resulting in low germinal transposition frequencies (0.37%) and high incidences of independent transposition (83%). The majority of these Ds elements (58%) transposed to genetically closed linked sites (≤10 cM)

    Green and efficient production of octyl hydroxyphenylpropionate using an ultrasound-assisted packed-bed bioreactor

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    A solvent-free system to produce octyl hydroxyphenylpropionate (OHPP) from p-hydroxyphenylpropionic acid (HPPA) and octanol using immobilized lipase (Novozym(A (R)) 435) as a catalyst in an ultrasound-assisted packed-bed bioreactor was investigated. Response-surface methodology (RSM) and a three-level-three-factor Box-Behnken design were employed to evaluate the effects of reaction temperature (x (1)), flow rate (x (2)) and ultrasonic power (x (3)) on the percentage of molar production of OHPP. The results indicate that the reaction temperature and flow rate were the most important variables in optimizing the production of OHPP. Based on a ridge max analysis, the optimum conditions for OHPP synthesis were predicted to consist of a reaction temperature of 65A degrees C, a flow rate of 0.05 ml/min and an ultrasonic power of 1.74 W/cm(2) with a yield of 99.25%. A reaction was performed under these optimal conditions, and a yield of 99.33 +/- A 0.1% was obtained

    The transition form factors for semi-leptonic weak decays of J/ψJ/\psi in QCD sum rules

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    Within the Standard Model, we investigate the semi-leptonic weak decays of J/ψJ/\psi. The various form factors of J/ψJ/\psi transiting to a single charmed meson (D(d,s)()D^{(*)}_{(d,s)}) are studied in the framework of the QCD sum rules. These form factors fully determine the rates of the weak semi-leptonic decays of J/ψJ/\psi and provide valuable information about the non-perturbative QCD effects. Our results indicate that the decay rate of the semi-leptonic weak decay mode J/ψDs()+e++νeJ/\psi \to D^{(*)-}_{s}+e^{+}+\nu_{e} is at order of 101010^{-10}.Comment: 28 pages, 6 figures, revised version to be published in Eur.Phys.J.
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