749 research outputs found

    Theta dependence of CP^9 model

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    We apply to the CP9CP^9 model two recently proposed numerical techniques for simulation of systems with a theta term. The algorithms, successfully tested in the strong coupling limit, are applied to the weak coupling region. The results agree and errors have been evaluated and are at % level. The results scale well with the renormalization group equation and show that, for CP9CP^9 in presence of a theta term, CP symmetry is spontaneously broken at Ξ=π\theta=\pi in the continuum limit.Comment: 4 pages, 4 figure

    Reconstruction and actual trends of landslide activities in Bruust–Haltiwald, Horw, canton of Lucerne, Switzerland

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    A spatiotemporal reconstruction of slope movements on the edge of Lake Lucerne near the municipality of Horw, canton of Lucerne, is presented. The reconstruction was realized by analyzing growth reactions of beech (Fagus sylvatica L.) and fir (Abies alba Mill.) trees growing on this slope. Before dendrochronological sampling, a detailed geomorphological mapping of the landslide was conducted with the aim to determine the spatial extent of the sliding area. For tree-ring analyses, 124 increment cores from 62 trees were analyzed following standard techniques of dendrogeomorphology. In addition, long micro-sections were prepared from the entire cores to extend the common eccentricity analyses by microscopic determination of the onset of reaction wood in fir and beech. Results clearly show that the area is moving at least since 1948. A significant concentration of events was observed between the years 1990 and 2000 as well as after 2006. The definition of a threshold to define events using an eccentricity index alone is problematic and needs to be adapted to specific site conditions. For this reason, we recommend always combining the application of an eccentricity index with a detailed visual (anatomical) inspection to check for the occurrence of reaction wood.</p

    Light hadron spectrum and quark masses in QCD with two flavors of dynamical quarks

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    We present updated results of the CP-PACS calculation of the light hadron spectrum in Nf=2N_{\rm f}=2 full QCD. Simulations are made with an RG-improved gauge action and a tadpole-improved clover quark action for sea quark masses corresponding to mPS/mV≈0.8m_{\rm PS}/m_{\rm V} \approx 0.8--0.6 and the lattice spacing a=0.22a=0.22--0.09 fm. A comparison of the full QCD spectrum with new quenched results, obtained with the same improved action, shows clearly the existence of sea quark effects in vector meson masses. Results for light quark masses in Nf=2N_{\rm f}=2 QCD are also presented.Comment: Latex 3 pages, 6 PostScript figures, Talk presented at LATTICE99(QCD Spectrum and Quark Masses

    Heavy Quarkonia from Anisotropic and Isotropic Lattices

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    We report on recent results for the spectrum of heavy quarkonia. Using coarse and anisotropic lattices we achieved an unprecedented control over statistical and systematic errors for higher excited states such as exotic hybrid states. In a parallel study on isotropic lattices we also investigate the effect of two dynamical flavours on the spin structure of charmonium and bottomonium for several symmetric lattices.Comment: LATTICE'99 (heavy quarks), 3 pages, 3 figure

    Eta meson mass and topology in QCD with two light flavors

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    We present results for the mass of the flavor singlet meson calculated on two-flavor full QCD configurations generated by the CP-PACS full QCD project. We also investigate topological charge fluctuations and their dependence on the sea quark mass.Comment: LATTICE99 (QCD Spectrum and Quark Masses), LaTeX(espcrc2.sty), 3 pages, 6 eps figure

    Equation of state in finite-temperature QCD with improved Wilson quarks

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    We study finite-temperature phase transition and equation of state for two-flavor QCD at Nt=4N_t=4 using an RG-improved gauge action and a meanfield-improved clover quark action. The pressure is computed using the integral method. The O(4) scaling of chiral order parameter is also examined.Comment: LATTICE99(finite temperature), 3 page

    Perfect topological charge for asymptotically free theories

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    The classical equations of motion of the perfect lattice action in asymptotically free d=2d=2 spin and d=4d=4 gauge models possess scale invariant instanton solutions. This property allows the definition of a topological charge on the lattice which is perfect in the sense that no topological defects exist. The basic construction is illustrated in the d=2d=2 O(3) non--linear σ\sigma--model and the topological susceptibility is measured to high precision in the range of correlation lengths Ο∈(2−60)\xi \in (2 - 60). Our results strongly suggest that the topological susceptibility is not a physical quantity in this model.Comment: Contribution to Lattice'94, 3 pages PostScript, uuencoded compresse

    Responding to Race Related Trauma: Counseling and Research Recommendations to Promote Post-Traumatic Growth when Counseling African American Males

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    The application of Post-Traumatic Growth, a resiliency based approach, for counselors working with African-American male clients who have experienced race-based trauma is described. The role of cognitive processing and meaning making are reviewed. Implications for counseling, education and research are provided

    Heavy-light decay constants from clover heavy quark action in QCD with two flavors of dynamical quarks

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    We present results on an analysis of the decay constants f_B and f_Bs with two flavours of sea quark. The calculation has been carried out on 3 different bare gauge couplings and 4 sea quark masses at each gauge coupling, with m_pi/m_rho ranging from 0.8 to 0.6. We employ the Fermilab formalism to perform calculations with heavy quarks whose mass is in the range of the b-quark. A detailed comparison with a quenched calculation using the same action is made to elucidate the effects due to the sea quarks.Comment: Contribution to Lattice 99 (Heavy Quarks). Latex file, uses espcrc2.sty and epsf.sty. 3 pages, 3 encapsulated postscript figure

    Distinct balance of excitation and inhibition in an interareal feedforward and feedback circuit of mouse visual cortex

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    Mouse visual cortex is subdivided into multiple distinct, hierarchically organized areas that are interconnected through feedforward (FF) and feedback (FB) pathways. The principal synaptic targets of FF and FB axons that reciprocally interconnect primary visual cortex (V1) with the higher lateromedial extrastriate area (LM) are pyramidal cells (Pyr) and parvalbumin (PV)-expressing GABAergic interneurons. Recordings in slices of mouse visual cortex have shown that layer 2/3 Pyr cells receive excitatory monosynaptic FF and FB inputs, which are opposed by disynaptic inhibition. Most notably, inhibition is stronger in the FF than FB pathway, suggesting pathway-specific organization of feedforward inhibition (FFI). To explore the hypothesis that this difference is due to diverse pathway-specific strengths of the inputs to PV neurons we have performed subcellular Channelrhodopsin-2-assisted circuit mapping in slices of mouse visual cortex. Whole-cell patch-clamp recordings were obtained from retrobead-labeled FF(V1→LM)- and FB(LM→V1)-projecting Pyr cells, as well as from tdTomato-expressing PV neurons. The results show that the FF(V1→LM) pathway provides on average 3.7-fold stronger depolarizing input to layer 2/3 inhibitory PV neurons than to neighboring excitatory Pyr cells. In the FB(LM→V1) pathway, depolarizing inputs to layer 2/3 PV neurons and Pyr cells were balanced. Balanced inputs were also found in the FF(V1→LM) pathway to layer 5 PV neurons and Pyr cells, whereas FB(LM→V1) inputs to layer 5 were biased toward Pyr cells. The findings indicate that FFI in FF(V1→LM) and FB(LM→V1) circuits are organized in a pathway- and lamina-specific fashion
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