337 research outputs found

    Comparison of articulate brachiopod nuclear and mitochondrial gene trees leads to a clade-based redefinition of protostomes (Protostomozoa) and deuterostomes (Deuterostomozoa)

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    Nuclear and mtDNA sequences from selected short-looped terebratuloid (terebratulacean) articulate brachiopods yield congruent and genetically independent phylogenetic reconstructions by parsimony, neighbor-joining and maximum likelihood methods, suggesting that both sources of data are reliable guides to brachiopod species phylogeny. The present-day genealogical relationships and geographical distributions of the tested terebratuloid brachiopods are consistent with a tethyan dispersal and subsequent radiation. Concordance of nuclear and mitochondrial gene phylogenies reinforces previous indications that articulate brachiopods, inarticulate brachiopods, phoronids and ectoprocts cluster with other organisms generally regarded as protostomes. Since ontogeny and morphology in brachiopods, ectoprocts and phoronids depart in important respects from those features supposedly diagnostic of protostomes, this demonstrates that the operational definition of protostomy by the usual ontological characters must be misleading or unreliable. New, molecular, operational definitions are proposed to replace the traditional criteria for the recognition of protostomes and deuterostomes, and the clade-based terms 'Protostomozoa' and 'Deuterostomozoa' are proposed to replace the existing terms 'Protostomia' and 'Deuterostomia'

    Effect of Nyquist Noise on the Nyquist Dephasing Rate in 2d Electron Systems

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    We measure the effect of externally applied broadband Nyquist noise on the intrinsic Nyquist dephasing rate of electrons in a two-dimensional electron gas at low temperatures. Within the measurement error, the phase coherence time is unaffected by the externally applied Nyquist noise, including applied noise temperatures of up to 300 K. The amplitude of the applied Nyquist noise from 100 MHz to 10 GHz is quantitatively determined in the same experiment using a microwave network analyzer.Comment: 5 pages, 4 figures. Author affiliation clarified; acknowledgements modified. Replacement reason clarifie

    Comparative study of density functional theories of the exchange-correlation hole and energy in silicon

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    We present a detailed study of the exchange-correlation hole and exchange-correlation energy per particle in the Si crystal as calculated by the Variational Monte Carlo method and predicted by various density functional models. Nonlocal density averaging methods prove to be successful in correcting severe errors in the local density approximation (LDA) at low densities where the density changes dramatically over the correlation length of the LDA hole, but fail to provide systematic improvements at higher densities where the effects of density inhomogeneity are more subtle. Exchange and correlation considered separately show a sensitivity to the nonlocal semiconductor crystal environment, particularly within the Si bond, which is not predicted by the nonlocal approaches based on density averaging. The exchange hole is well described by a bonding orbital picture, while the correlation hole has a significant component due to the polarization of the nearby bonds, which partially screens out the anisotropy in the exchange hole.Comment: 16 pages, 5 figures, RevTeX, added conten

    Measurement of Exclusive rho+rho- Production in Mid-Virtuality Two-Photon Interactions and Study of the gamma gamma* -> rho rho Process at LEP

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    Exclusive rho+rho- production in two-photon collisions between a quasi-real photon, gamma, and a mid-virtuality photon, gamma*, is studied with data collected at LEP at centre-of-mass energies root(s)=183-209GeV with a total integrated luminosity of 684.8pb^-1. The cross section of the gamma gamma* -> rho+ rho- process is determined as a function of the photon virtuality, Q^2, and the two-photon centre-of-mass energy, W_gg, in the kinematic region: 0.2GeV^2 < Q^2 <0.85GeV^2 and 1.1GeV < W_gg < 3GeV. These results, together with previous L3 measurements of rho0 rho0 and rho+ rho- production, allow a study of the gamma gamma* -> rho rho process over the Q^2-region 0.2GeV^2 < Q^2 < 30 GeV^2

    Measurement of Exclusive rho^0 rho^0 Production in Mid-Virtuality Two-Photon Interactions at LEP

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    Exclusive rho^0 rho^0 production in two-photon collisions between a quasi-real and a mid-virtuality photon is studied with data collected at LEP at centre-of-mass energies 183GeV < sqrt{s} < 209GeV with a total integrated luminosity of 684.8/pb. The cross section of the process gamma gamma* -> rho^0 rho^0 is determined as a function of the photon virtuality, q^2, and the two-photon centre-of-mass energy, Wgg, in the kinematic region: 0.2GeV^2 < q^2 < 0.85GeV^2 and 1.1GeV < Wgg < 3GeV

    Global Search for New Physics with 2.0/fb at CDF

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    Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for "bumps" that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0/fb of ppbar collisions at sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D Rapid Communication

    Relatório de estágio na Câmara Municipal de Ourém

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    O presente relatório enquadra-se no âmbito do trabalho final do curso Mestrado em Reabilitação Urbana, do Instituto Politécnico de Tomar. O estágio decorreu na Câmara Municipal de Ourém e teve como objeto, participar na coordenação com a Divisão Obras Municipais, Divisão da Ação Cultural e Divisão de Educação e Assuntos Sociais em intervenções a nível da Reabilitação Urbana. O estágio numa Câmara Municipal foi a opção que pareceu mais enriquecedora para conclusão do Mestrado em Reabilitação Urbana e para o futuro da minha vida profissional. Esta opção de estágio deve-se ao desejo de poder aplicar alguns dos conhecimentos obtidos ao longo do Mestrado, de conhecer a realidade do trabalho em obra e inserido numa equipa profissional, fiscalizadora, lidando com as responsabilidades inerentes à profissão. O relatório aborda quatro casos de estudo, respeitante às reabilitações, 1ª fase de intervenção na capela de São Sebastião em Atouguia, 2ª fase da reabilitação de zona de lazer no Agroal, freguesia de Formigais, 1ª fase de intervenção da capela da Perucha e reforço do pontão de Caxarias. Acompanhamento de pequenas reabilitações, reclamadas por juntas de freguesia e munícipes. O relatório procura descrever os procedimentos adotados no acompanhamento das obras de reabilitação e para fácil entendimento as descrições são acompanhadas por fotografias

    Customer emotions in service failure and recovery encounters

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    Emotions play a significant role in the workplace, and considerable attention has been given to the study of employee emotions. Customers also play a central function in organizations, but much less is known about customer emotions. This chapter reviews the growing literature on customer emotions in employee–customer interfaces with a focus on service failure and recovery encounters, where emotions are heightened. It highlights emerging themes and key findings, addresses the measurement, modeling, and management of customer emotions, and identifies future research streams. Attention is given to emotional contagion, relationships between affective and cognitive processes, customer anger, customer rage, and individual differences

    Determination of the Form Factors for the Decay B0 --> D*-l+nu_l and of the CKM Matrix Element |Vcb|

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    We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element Vcb|V_{cb}| and of the parameters ρ2\rho^2, R1R_1, and R2R_2, which fully characterize the form factors of the B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decay in the framework of HQET, based on a sample of about 52,800 B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decays recorded by the BABAR detector. The kinematical information of the fully reconstructed decay is used to extract the following values for the parameters (where the first errors are statistical and the second systematic): ρ2=1.156±0.094±0.028\rho^2 = 1.156 \pm 0.094 \pm 0.028, R1=1.329±0.131±0.044R_1 = 1.329 \pm 0.131 \pm 0.044, R2=0.859±0.077±0.022R_2 = 0.859 \pm 0.077 \pm 0.022, F(1)Vcb=(35.03±0.39±1.15)×103\mathcal{F}(1)|V_{cb}| = (35.03 \pm 0.39 \pm 1.15) \times 10^{-3}. By combining these measurements with the previous BABAR measurements of the form factors which employs a different technique on a partial sample of the data, we improve the statistical accuracy of the measurement, obtaining: ρ2=1.179±0.048±0.028,R1=1.417±0.061±0.044,R2=0.836±0.037±0.022,\rho^2 = 1.179 \pm 0.048 \pm 0.028, R_1 = 1.417 \pm 0.061 \pm 0.044, R_2 = 0.836 \pm 0.037 \pm 0.022, and F(1)Vcb=(34.68±0.32±1.15)×103. \mathcal{F}(1)|V_{cb}| = (34.68 \pm 0.32 \pm 1.15) \times 10^{-3}. Using the lattice calculations for the axial form factor F(1)\mathcal{F}(1), we extract Vcb=(37.74±0.35±1.25±1.441.23)×103|V_{cb}| =(37.74 \pm 0.35 \pm 1.25 \pm ^{1.23}_{1.44}) \times 10^{-3}, where the third error is due to the uncertainty in F(1)\mathcal{F}(1)

    Measurement of Exclusive \rho^+\rho^- Production in High-Q^2 Two-Photon Collisions at LEP

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    Exclusive rho^+ rho^- production in two-photon collisions involving a single highly-virtual photon is studied with data collected at LEP at centre-of-mass energies 89 GeV < \sqrt{s} < 209 GeV with a total integrated luminosity of 854.7 pb^-1. The cross section of the process gamma gamma^* -> rho^+ rho^- is determined as a function of the photon virtuality, Q^2, and the two-photon centre-of-mass energy, W_gg, in the kinematic region: 1.2 GeV^2 < Q^2 < 30 GeV^2 and 1.1 GeV < W_gg < 3 GeV. The \rho^+\rho^- production cross section is found to be of the same magnitude as the cross section of the process gamma gamma^* -> rho^0 rho^0, measured in the same kinematic region by L3, and to have similar W_gg and Q^2 dependences
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