270 research outputs found

    12 Years of Precision Calculations for LEP. What's Next?

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    I shortly review time period of twelve years, 1989-2000, which was devoted to a theoretical support of experiments at LEP and SLC at Z resonance and discuss several directions of possible future work in the field of precision theoretical calculations for experiments at future colliders.Comment: 11 Latex, including 1 figures. Updated version as appeared in the Journa

    Half a Century of Supreme Court Clean Air Act Interpretation: Purposivism, Textualism, Dynamism, and Activism

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    This Article addresses the history of the Supreme Court’s interpretation of the Clean Air Act, which now goes back almost half a century. Many scholars have argued that the Court has shifted from an approach to statutory interpretation that relied heavily on purposivism—the custom of giving statutory goals weight in interpreting statutes—toward one that relies more heavily on textualism during this period. At the same time, proponents of dynamic statutory interpretation have argued that courts, in many cases, do not so much excavate a statute’s meaning as adapt a statute to contemporary circumstances

    Automatic one-loop calculation of MSSM processes with GRACE

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    We have developed the system for the automatic computation of cross-sections, {\tt GRACE/SUSY}, including the one-loop calculations for processes of the minimal supersymmetric extension of the the standard model. For an application, we investigate the process e+eZ0h0e^+ e^- \to Z^0 h^0 .Comment: 4 pages, 1 figure, Talk presented by Jimbo, M. at ACAT-0

    Actionneur à deux degrés de liberté pour micro robot mobile

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    Ce projet présente un actionneur à deux degrés de liberté (mouvement verticale et rotation) pour des micro-robots mobiles. L’actionneur possède un encombrement de 12 x 10.4 x 3 mm3 et une course de 5.5 mm. L’actionnement est basé sur le principe du stick-slip avec des actionneurs piézo-électriques avec des pieds conducteurs pour éviter des fils. L’actionneur est capable de soulever un poids de 2.5 g et présente des vitesses maximales de 0.7 mm/s en verticale et 0.18 rad/s en rotation

    Cyclosporine A reduces microvascular obstruction and preserves left ventricular function deterioration following myocardial ischemia and reperfusion

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    Postconditioning and cyclosporine A prevent mitochondrial permeability transition pore opening providing cardioprotection during ischemia/reperfusion. Whether microvascular obstruction is affected by these interventions is largely unknown. Pigs subjected to coronary occlusion for 1 h followed by 3 h of reperfusion were assigned to control (n = 8), postconditioning (n = 9) or cyclosporine A intravenous infusion 10-15 min before the end of ischemia (n = 8). Postconditioning was induced by 8 cycles of repeated 30-s balloon inflation and deflation. After 3 h of reperfusion magnetic resonance imaging, triphenyltetrazolium chloride/Evans blue staining and histopathology were performed. Microvascular obstruction (MVO, percentage of gadolinium-hyperenhanced area) was measured early (3 min) and late (12 min) after contrast injection. Infarct size with double staining was smaller in cyclosporine (46.2 ± 3.1 %, P = 0.016) and postconditioning pigs (47.6 ± 3.9 %, P = 0.008) versus controls (53.8 ± 4.1 %). Late MVO was significantly reduced by cyclosporine (13.9 ± 9.6 %, P = 0.047) but not postconditioning (23.6 ± 11.7 %, P = 0.66) when compared with controls (32.0 ± 16.9 %). Myocardial blood flow in the late MVO was improved with cyclosporine versus controls (0.30 ± 0.06 vs 0.21 ± 0.03 ml/g/min, P = 0.002) and was inversely correlated with late-MVO extent (R2R^{2} = 0.93, P\0.0001). Deterioration of left ventricular ejection fraction (LVEF) between baseline and 3 h of reperfusion was smaller with cyclosporine (-7.9 ± 2.4 %, P = 0.008) but not postconditioning (-12.0 ± 5.5 %, P = 0.22) when compared with controls (-16.4 ± 5.5 %). In the three groups, infarct size (\beta = -0.69, P\0.001) and late MVO (\beta = -0.33, P = 0.02) were independent predictors of LVEF deterioration following ischemia/reperfusion (R^{2} = 0.73, P\0.001). Despite both cyclosporine A and postconditioning reduce infarct size, only cyclosporine A infusion had a beneficial effect on microvascular damage and was associated with better preserved LV function when compared with controls

    Itinerant ferromagnetism mediated by giant spin polarization of metallic ligand band in van der Waals magnet Fe5GeTe2

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    We investigate near-Fermi-energy (EF) element-specific electronic and spin states of ferromagnetic van der Waals (vdW) metal Fe5GeTe2. The soft x-ray angle-resolved photoemission spectroscopy (SX-ARPES) measurement provides spectroscopic evidence of localized Fe 3d band. We also find prominent hybridization between the localized Fe 3d band and the delocalized Ge/Te p bands. This picture is strongly supported from direct observation of the remarkable spin polarization of the ligand p bands near EF, using x-ray magnetic circular dichroism (XMCD) measurements. The strength of XMCD signal from ligand element Te shows the highest value, as far as we recognize, among literature reporting finite XMCD signal for none-magnetic element in any systems. Combining SX-ARPES and elemental selective XMCD measurements, we collectively point an important role of giant spin polarization of the delocalized ligand Te states for realizing itinerant long-range ferromagnetism in Fe5GeTe2. Our finding provides a fundamental elemental selective view-point for understanding mechanism of itinerant ferromagnetism in low dimensional compounds, which also leads insight for designing exotic magnetic states by interfacial band engineering in heterostructures

    The Higgs - photon - Z boson coupling revisited

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    We analyze the coupling of CP-even and CP-odd Higgs bosons to a photon and a Z boson in extensions of the Standard Model. In particular, we study in detail the effect of charged Higgs bosons in two-Higgs doublet models, and the contribution of SUSY particle loops in the minimal supersymmetric extension of the Standard Model. The Higgs-γZ\gamma Z coupling can be measured in the decay ZγZ \to \gamma+Higgs at e+ee^+e^- colliders running on the Z resonance, or in the reverse process Higgs Zγ\to Z \gamma with the Higgs boson produced at LHC. We show that a measurement of this coupling with a precision at the percent level, which could be the case at future e+ee^+e^- colliders, would allow to distinguish between the lightest SUSY and standard Higgs bosons in large areas of the parameter space.Comment: 18 pages LaTex + 7 figures (ps). Typo corrected in eq.(5

    Probing scalar-pseudoscalar mixing in the CP violating MSSM at high-energy e+ee^+e^- colliders

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    We study the production processes e+eHi0Ze^+e^-\to H^0_iZ, Hi0Hj0H^0_iH^0_j and Hi0νeνeH^0_i\nu_e\overline \nu_e in the context of the CP violating MSSM. In a given channel we show that the cross-section for all i (=1,2,3) can be above 0.1 fb provided M_{H_{2,3}}\la 300 GeV. This should be detectable at a Next Linear Collider and would provide evidence for scalar-pseudoscalar mixing.Comment: 17 pages, RevTex, 4 ps figures, figure 4 changed, minor modifications to text, version to appear in PR

    Analytic properties of the Landau gauge gluon and quark propagators

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    We explore the analytic structure of the gluon and quark propagators of Landau gauge QCD from numerical solutions of the coupled system of renormalized Dyson--Schwinger equations and from fits to lattice data. We find sizable negative norm contributions in the transverse gluon propagator indicating the absence of the transverse gluon from the physical spectrum. A simple analytic structure for the gluon propagator is proposed. For the quark propagator we find evidence for a mass-like singularity on the real timelike momentum axis, with a mass of 350 to 500 MeV. Within the employed Green's functions approach we identify a crucial term in the quark-gluon vertex that leads to a positive definite Schwinger function for the quark propagator.Comment: 42 pages, 16 figures, revtex; version to be published in Phys Rev
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