1,166 research outputs found

    Growth, profits and technological choice: The case of the Lancashire cotton textile industry

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    Using Lancashire textile industry company case studies and financial records, mainly from the period just before the First World War, the processes of growth and decline are re-examined. These are considered by reference to the nature of Lancashire entrepreneurship and the impact on technological choice. Capital accumulation, associated wealth distributions and the character of Lancashire business organisation were sybiotically linked to the success of the industry before 1914. However, the legacy of that accumulation in later decades, chronic overcapacity, formed a barrier to reconstruction and enhanced the preciptious decline of a once great industry

    Theta-13 as a Probe of Mu-Tau symmetry for Leptons

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    Many experiments are being planned to measure the neutrino mixing parameter θ13\theta_{13} using reactor as well as accelerator neutrino beams. In this note, the theoretical significance of a high precision measurement of this parameter is discussed. It is emphasized that it will provide crucial information about different ways to understand the origin of large atmospheric neutrino mixing and move us closer towards determining the neutrino mass matrix. For instance if exact μ↔τ\mu\leftrightarrow \tau symmetry in the neutrino mass matrix is assumed to be the reason for maximal νμ−ντ\nu_\mu-\nu_\tau mixing, one gets θ13=0\theta_{13}=0. Whether θ13≃Δm⊙2/ΔmA2\theta_{13}\simeq \sqrt{\Delta m^2_{\odot}/\Delta m^2_A} or θ13≃Δm⊙2/ΔmA2\theta_{13}\simeq \Delta m^2_{\odot}/\Delta m^2_A can provide information about the way the μ↔τ\mu\leftrightarrow \tau symmetry breaking manifests in the case of normal hierarchy. We also discuss the same question for inverted hierarchy as well as possible gauge theories with this symmetry.Comment: 12 pages; no figures; latex; more exact expressions given for some parameters and minor typos corrected; paper accepted for publication in JHE

    ß-Methylphenylethylamines: Common fragmentation pathways with amphetamines in electrospray ionization collision-induced dissociation

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    β-Methylphenylethylamines are positional isomers of amphetamines and have been discovered in sporting supplements. Although the fragmentation of the β-methylphenylethylamine and N-methyl-β-methylphenylethylamine in gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) systems is significantly different to their amphetamine and methylamphetamine isomers, under electrospray ionization commonly used in liquid chromatography-mass spectrometry (LC-MS) systems, the fragmentation of each of the isomeric pairs is almost identical. The similarities in fragmentation make it possible for the misidentification of the β-methylphenylethylamines as the illicit amphetamines. It is proposed that the similarities are due to a fragmentation pathway involving a common phenonium ion intermediate. By careful control of fragmentation energies in liquid chromatography-tandem mass spectrometry (LC-MS/MS) systems and/or close examination of the relative abundances of product ions formed by collision-induced dissociation (qualifier ratios), it is possible to distinguish the β-methylphenylethylamines from the amphetamines, even if significant retention time separation is not achieved. In liquid chromatography-electrospray ionization-quadrupole time of flight (LC-ESI-QTOF) systems the mass spectra of the β-methylphenylethylamines are identical to their amphetamine isomers. In such systems, retention time separation of the isomers is critical to avoid misidentification. During this study β-methylphenylethylamine and N-methyl-β-methylphenylethylamine have been identified in commercially available sporting supplements and oral fluid samples taken during the course of road-side drugs-in-drivers and workplace testing programmes

    Integrate and Fire Neural Networks, Piecewise Contractive Maps and Limit Cycles

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    We study the global dynamics of integrate and fire neural networks composed of an arbitrary number of identical neurons interacting by inhibition and excitation. We prove that if the interactions are strong enough, then the support of the stable asymptotic dynamics consists of limit cycles. We also find sufficient conditions for the synchronization of networks containing excitatory neurons. The proofs are based on the analysis of the equivalent dynamics of a piecewise continuous Poincar\'e map associated to the system. We show that for strong interactions the Poincar\'e map is piecewise contractive. Using this contraction property, we prove that there exist a countable number of limit cycles attracting all the orbits dropping into the stable subset of the phase space. This result applies not only to the Poincar\'e map under study, but also to a wide class of general n-dimensional piecewise contractive maps.Comment: 46 pages. In this version we added many comments suggested by the referees all along the paper, we changed the introduction and the section containing the conclusions. The final version will appear in Journal of Mathematical Biology of SPRINGER and will be available at http://www.springerlink.com/content/0303-681

    Non-equilibrium stationary state of a two-temperature spin chain

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    A kinetic one-dimensional Ising model is coupled to two heat baths, such that spins at even (odd) lattice sites experience a temperature TeT_{e} (% T_{o}). Spin flips occur with Glauber-type rates generalised to the case of two temperatures. Driven by the temperature differential, the spin chain settles into a non-equilibrium steady state which corresponds to the stationary solution of a master equation. We construct a perturbation expansion of this master equation in terms of the temperature difference and compute explicitly the first two corrections to the equilibrium Boltzmann distribution. The key result is the emergence of additional spin operators in the steady state, increasing in spatial range and order of spin products. We comment on the violation of detailed balance and entropy production in the steady state.Comment: 11 pages, 1 figure, Revte

    HER2 testing in breast cancer: Opportunities and challenges

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    Human epidermal growth factor receptor 2 (HER2) is overexpressed in 15-25% of breast cancers, usually as a result of HER2 gene amplification. Positive HER2 status is considered to be an adverse prognostic factor. Recognition of the role of HER2 in breast cancer growth has led to the development of anti-HER2 directed therapy, with the humanized monoclonal antibody trastuzumab (Herceptin (R)) having been approved for the therapy of HER2-positive metastatic breast cancer. Clinical studies have further suggested that HER2 status can provide important information regarding success or failure of certain hormonal therapies or chemotherapies. As a result of these developments, there has been increasing demand to perform HER2 testing on current and archived breast cancer specimens. This article reviews the molecular background of HER2 function, activation and inhibition as well as current opinions concerning its role in chemosensitivity and interaction with estrogen receptor biology. The different tissue-based assays used to detect HER2 amplification and overexpression are discussed with respect to their advantages and disadvantages, when to test (at initial diagnosis or pre-treatment), where to test (locally or centralized) and the need for quality assurance to ensure accurate and valid testing results

    Neutrino Mass from R-parity Violation in Split Supersymmetry

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    We investigate how the observed neutrino data can be accommodated by R-parity violation in Split Supersymmetry. The atmospheric neutrino mass and mixing are explained by the bilinear parameters ξi\xi_i inducing the neutrino-neutralino mixing as in the usual low-energy supersymmetry. Among various one-loop corrections, only the quark-squark exchanging diagrams involving the order-one trilinear couplings λi23,i32′\lambda'_{i23,i32} can generate the solar neutrino mass and mixing if the scalar mass mSm_S is not larger than 10910^9 GeV. This scheme requires an unpleasant hierarchical structure of the couplings, e.g., λi23,i32∼1\lambda_{i23,i32}\sim 1, λi33′≲10−4\lambda'_{i33} \lesssim 10^{-4} and ξi≲10−6\xi_i \lesssim 10^{-6}. On the other hand, the model has a distinct collider signature of the lightest neutralino which can decay only to the final states, liW(∗)l_i W^{(*)} and νZ(∗)\nu Z^{(*)}, arising from the bilinear mixing. Thus, the measurement of the ratio; Γ(eW(∗)):Γ(μW(∗)):Γ(τW(∗))\Gamma(e W^{(*)}) : \Gamma(\mu W^{(*)}) : \Gamma(\tau W^{(*)}) would provide a clean probe of the small reactor and large atmospheric neutrino mixing angles as far as the neutralino mass is larger than 62 GeV.Comment: 10 pages, 3 figures, version submitted to JHE
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