47,585 research outputs found

    Investor Protection and the Value Effects of Bank Merger Announcements in Europe and the US

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    Investor protection regimes have been shown to partly explain why the same type of corporate event may attract different investor reactions across countries. We compare the value effects of large bank merger announcements in Europe and the US and find an inverse relationship between the level of investor protection prevalent in the target country and abnormal returns that bidders realize during the announcement period. Accordingly, bidding banks realize higher returns when targeting low protection economies (most European economies) than bidders targeting institutions which operate under a high investor protection regime (the US). We argue that bidding bank shareholders need to be compensated for an increased risk of expropriation by insiders which they face in a low protection environment where takeover markets are illiquid and there are high private benefits of control

    A systematic review of whole class, subject based, pedagogies with reported outcomes for the academic and social inclusion of pupils with special educational needs in mainstream classrooms

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    Schools across the world have responded to international and national initiatives designed to further the development of inclusive education. In England, there is a statutory requirement for all schools to provide effective learning opportunities for all pupils (QCA, 2000) and children with special educational needs (SEN) are positioned as having a right to be within mainstream classrooms accessing an appropriate curriculum (SENDA, 2001). Previous reviews which have sought to identify classroom practices that support the inclusion of children with SEN have been technically non-systematic and hence a need for a systematic review within this area has been identified (Nind et al., 2004; Rix et al., 2006). This systematic literature review is the last in a series of three

    Relative distributions of W's and Z's at low transverse momenta

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    Despite large uncertainties in the W±W^\pm and Z0Z^0 transverse momentum (qTq_T) distributions for q_T\lsim 10 GeV, the ratio of the distributions varys little. The uncertainty in the ratio of WW to ZZ qTq_T distributions is on the order of a few percent, independent of the details of the nonperturbative parameterization.Comment: 13 pages in revtex, 5 postscript figures available upon request, UIOWA-94-0

    Novel theoretical approach in photoemission spectroscopy: application to isotope effect and boron-doped diamond

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    A new path-integral theory is developed to calculate the photoemission spectra (PES) of correlated many-electron systems. The application to the study on Bi2Sr2CaCu2O8 (Bi2212) and boron-doped diamond (BDD) is discussed in details. It is found that the isotopic shift in the angle-resolved photoemission spectra of Bi2212 is due to the off-diagonal quadratic electron-phonon (e-ph) coupling, whereas the presence of electron-electron repulsion partially suppresses this effect. For the BDD, a semiconductor-metal phase transition, which is induced by increasing the e-ph coupling and dopant concentration, is reproduced by our theory. Additionally, the presence of Fermi edge and phonon step-like structure in PES is found to be due to a co-existence of itinerant and localized electronic states in BDD.Comment: 6 pages, 4 figures, Procs. of LEHTSC 2007, submitted to J. Phys.: Conf. Se

    Hard-scattering factorization with heavy quarks: A general treatment

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    A detailed proof of hard scattering factorization is given with the inclusion of heavy quark masses. Although the proof is explicitly given for deep-inelastic scattering, the methods apply more generally The power-suppressed corrections to the factorization formula are uniformly suppressed by a power of \Lambda/Q, independently of the size of heavy quark masses, M, relative to Q.Comment: 52 pages. Version as published plus correction of misprint in Eq. (45

    Dijet imbalance in hadronic collisions

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    The imbalance of dijets produced in hadronic collisions has been used to extract the average transverse momentum of partons inside the hadrons. In this paper we discuss new contributions to the dijet imbalance that could complicate or even hamper this extraction. They are due to polarization of initial state partons inside unpolarized hadrons that can arise in the presence of nonzero parton transverse momentum. Transversely polarized quarks and linearly polarized gluons produce specific azimuthal dependences of the two jets that in principle are not suppressed. Their effects cannot be isolated just by looking at the angular deviation from the back-to-back situation, rather they enter jet broadening observables. In this way they directly affect the extraction of the average transverse momentum of unpolarized partons that is thought to be extracted. We discuss appropriately weighted cross sections to isolate the additional contributions.Comment: 15 pages, 2 figures; revised version, published in Phys. Rev.

    Three-Loop Mixing of Dipole Operators

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    We calculate the complete three-loop O(alpha_s^3) anomalous dimension matrix for the dimension-five dipole operators that arise in the Standard Model after integrating out the top quark and the heavy electroweak bosons. Our computation completes the three-loop anomalous dimension matrix of operators that govern low-energy |Delta F| = 1 flavor-changing processes, and represents an important ingredient of the next-to-next-to-leading order QCD analysis of the Bbar -> X_s gamma decay.Comment: 4 pages, 1 figure; journal version, text below Eq. (7) correcte

    Renormalization and resummation in finite temperature field theories

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    Resummation, ie. reorganization of perturbative series, can result in an inconsistent perturbation theory, unless the counterterms are reorganized in an appropriate way. In this paper two methods are presented for resummation of counterterms: one is a direct method where the necessary counterterms are constructed order by order; the other is a general one, based on renormalization group arguments. We demonstrate at one hand that, in mass independent schemes, mass resummation can be performed by gap equations renormalized prior to the substitution of the resummed mass for its argument. On the other hand it is shown that any (momentum-independent) form of mass and coupling constant resummation is compatible with renormalization, and one can explicitly construct the corresponding counterterms.Comment: 10 pages, 4 figures, revtex

    Nuclear Effects on Heavy Boson Production at RHIC and LHC

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    We predict W and Z transverse momentum distributions from proton-proton and nuclear collisions at RHIC and LHC. A resummation formalism with power corrections to the renormalization group equations is used. The dependence of the resummed QCD results on the non-perturbative input is very weak for the systems considered. Shadowing effects are discussed and found to be unimportant at RHIC, but important for LHC. We study the enhancement of power corrections due to multiple scattering in nuclear collisions and numerically illustrate the weak effects of the dependence on the nuclear mass.Comment: 21 pages, 11 figure
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