2,066 research outputs found

    High-Energy String Scattering Amplitudes and Signless Stirling Number Identity

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    We give a complete proof of a set of identities (7) proposed recently from calculation of high-energy string scattering amplitudes. These identities allow one to extract ratios among high-energy string scattering amplitudes in the fixed angle regime from high-energy amplitudes in the Regge regime. The proof is based on a signless Stirling number identity in combinatorial theory. The results are valid for arbitrary real values LL rather than only for L=0,1L=0,1 proved previously. The identities for non-integer real value LL were recently shown to be realized in high-energy compactified string scattering amplitudes [He S., Lee J.C., Yang Y., arXiv:1012.3158]. The parameter LL is related to the mass level of an excited string state and can take non-integer values for Kaluza-Klein modes

    Properties of Hydrogel-Wood Composite as a New Thermochromic Glazing Material

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    Recently, thermal-response hydrogel smart window is widely studied because of its high luminous transmittance (τlum) and high solar modulation ability (Δτsol). However, its liquid state is undesirable for window applications. Wood has strong mechanical strength and low thermal conductivity. Due to the unique features of the thermal-response hydrogel and wood, a thermochromic hydrogel wood composite (HWC) that can smartly regulate solar irradiation is proposed by impregnating a thermal-response hydrogel into delignified wood. The novel HWC demonstrates advanced optical properties (i.e. τlum = 83% and 40% at the cold transparent and hot opaque states & Δτsol = 38%) and low transition temperature (i.e. Tc = 23 oC). Moreover, the HWC is highly flexible and easily fitted into existing windows frames. Overall, the HWC with its impressive features shows great promise for energy-efficient material for smart windows in buildings.publishedVersio

    Identifying risks in China's counter-terrorism policy

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    published_or_final_versionInternational and Public AffairsMasterMaster of International and Public Affair

    The Evolution of Density Structure of Starless and Protostellar Cores

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    We present a near-infrared extinction study of nine dense cores at evolutionary stages between starless to Class I. Our results show that the density structure of all but one observed cores can be modeled with a single power law rho \propto r^p between ~ 0.2R-R of the cores. The starless cores in our sample show two different types of density structures, one follows p ~ -1.0 and the other follows p ~ -2.5, while the protostellar cores all have p ~ -2.5. The similarity between the prestellar cores with p ~ -2.5 and protostellar cores implies that those prestellar cores could be evolving towards the protostellar stage. The slope of p ~ -2.5 is steeper than that of an singular isothermal sphere, which may be interpreted with the evolutionary model of cores with finite mass.Comment: 19 pages, 3 figures, accepted for publication in the Astrophysical Journa

    Green Building Rating Systems and Construction Waste in High Density Urban Environment: The Case Study of Hong Kong

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    Hong Kong, as many other countries, is currently facing a waste management crisis with the shortage of reclamation sites and landfill space. Examination of construction waste management (CWM) criteria within Hong Kong’s BEAM Plus is limited and lacking. In this paper, CWM criteria were assessed and a case study was conducted on a recent project, pursuing BEAM Plus, to assess the effectiveness of CWM criteria to facilitate waste reduction. The findings revealed that the overall impact of BEAM Plus on construction waste reduction is negligible. The case study showed that the reasons material/waste-related credits are not commonly attempted is due to the lack of minimum thresholds and a low weighting relative to credits in other categories. In the case study, waste generated per constructed floor area was 0.21 tons/m2. This paper also makes recommendations to improve CWM criteria in BEAM Plus in order to promote a more sustainable building industry

    Application of Flexible Micro Temperature Sensor in Oxidative Steam Reforming by a Methanol Micro Reformer

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    Advances in fuel cell applications reflect the ability of reformers to produce hydrogen. This work presents a flexible micro temperature sensor that is fabricated based on micro-electro-mechanical systems (MEMS) technology and integrated into a flat micro methanol reformer to observe the conditions inside that reformer. The micro temperature sensor has higher accuracy and sensitivity than a conventionally adopted thermocouple. Despite various micro temperature sensor applications, integrated micro reformers are still relatively new. This work proposes a novel method for integrating micro methanol reformers and micro temperature sensors, subsequently increasing the methanol conversion rate and the hydrogen production rate by varying the fuel supply rate and the water/methanol ratio. Importantly, the proposed micro temperature sensor adequately controls the interior temperature during oxidative steam reforming of methanol (OSRM), with the relevant parameters optimized as well

    Publishing Scientifically Sound Papers in Traditional and Complementary Medicine

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    [[abstract]]Non-conventional medical practices that make use of dietary supplements, herbal extracts, physical manipulations, and other practices typically associated with folk and Traditional Medicine are increasingly becoming popular in Western Countries. These practices are commonly referred to by the generic, all-inclusive term “Complementary and Alternative Medicine.” Scientists, practitioners, and medical institutions bear the responsibility of testing and proving the effectiveness of these non-conventional medical practices in the interest of patients. In this context, the number of peer-reviewed journals and published articles on this topic has greatly increased in the recent decades. In this editorial article, we illustrate the policy of the Journal of Traditional and Complementary Medicine for publishing solid and scientifically sound papers in the field of Traditional and Complementary Medicine.[[notice]]補正完

    High Prevalence of Mutations in Quinolone-resistance-determining Regions and mtrR Loci in Polyclonal Neisseria gonorrhoeae Isolates at a Tertiary Hospital in Southern Taiwan

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    Background/PurposeThe emergence of multidrug-resistant Neisseria gonorrhoeae is a great challenge in controlling gonorrhea. This study was conducted to survey the prevalence of molecular mechanisms of antimicrobial resistance among 45 clinical isolates of N. gonorrhoeae collected at a university hospital in Southern Taiwan during 1999-2004.MethodsMutations in mtrR loci and quinolone-resistance-determining regions (QRDRs) were examined by gene sequencing. Polymerase chain reactions with specific primers were performed to detect ermA, ermB, ermC, and ermF. Serogroups and serovars were determined by commercial kits.ResultsThe percentage of multidrug resistance, that is, resistance to penicillin, tetracycline, erythromycin, and ciprofloxacin, among the 45 isolates was 40%. Ceftriaxone and spectinomycin were active against all isolates in vitro. The frequency of mutations in the QRDR and mtrR promoter was 82.2% and 93.3%, respectively. Eighty-two percent of the isolates carried mutations both in the QRDR and mtrR loci. Of nine mutation profiles with QRDR mutations (n =37), gyrA-Ser91Phe/gyrA-Asp95Gly/parC-Ser87Arg was the most common type (56.8%). Acquired genes for rRNA methylase were detected in 11 isolates (10 ermB and 1 ermA). Twenty-seven serovars were identified and all belonged to serogroup B, which suggested that multiple clones of N. gonorrhoeae were circulating in the community in the Tainan area.ConclusionThe high prevalence of multidrug resistance caused by varied resistance mechanisms in N. gonorrhoeae limits the drug choice. Ongoing surveillance of antimicrobial resistance and discovery of new effective antibiotic therapy are warranted in endemic areas

    Lasing on nonlinear localized waves in curved geometry

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    The use of geometrical constraints opens many new perspectives in photonics and in fundamental studies of nonlinear waves. By implementing surface structures in vertical cavity surface emitting lasers as manifolds for curved space, we experimentally study the impacts of geometrical constraints on nonlinear wave localization. We observe localized waves pinned to the maximal curvature in an elliptical-ring, and confirm the reduction in the localization length of waves by measuring near and far field patterns, as well as the corresponding dispersion relation. Theoretically, analyses based on a dissipative model with a parabola curve give good agreement remarkably to experimental measurement on the transition from delocalized to localized waves. The introduction of curved geometry allows to control and design lasing modes in the nonlinear regime.Comment: 6 pages, 6 figure
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