700 research outputs found

    IT Program Goal Interdependence and Team Process Adjustment

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    IT programs are a common management structure put in place to govern multiple IT projects and complex IT deployments. The presence of multiple project teams can lead to difficulties in driving toward a common organizational goal for the program. One desirable behavior for program teams is the ability to adjust to changes in requirements due to environmental shifts or errors in requirements. We develop a model that considers how adjustments are fostered. The model suggests that goal interdependence and commitment, combined with monitoring, lead to heightened adjustment behaviors. Adjustment behaviors, in turn, lead to desirable program outcomes, but the relationships are moderated by requirements uncertainty

    The g-2 of the Muon in Localized Gravity Models

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    The (g-2) of the muon is well known to be an important model building constraint on theories beyond the Standard Model. In this paper, we examine the contributions to (g2)μ(g-2)_\mu arising in the Randall-Sundrum model of localized gravity for the case where the Standard Model gauge fields and fermions are both in the bulk. Using the current experimental world average measurement for (g2)μ(g-2)_\mu, we find that strong constraints can be placed on the mass of the lightest gauge Kaluza-Klein excitation for a narrow part of the allowed range of the assumed universal 5-dimensional fermion mass parameter, ν\nu. However, employing both perturbativity and fine-tuning constraints we find that we can further restrict the allowed range of the parameter ν\nu to only one fourth of its previous size. The scenario with the SM in the RS bulk is thus tightly constrained, being viable for only a small region of the parameter space.Comment: 16 pages, 2 figs, LaTex, Additional discussion adde

    Constraints on the nonuniversal Z^\prime couplings from B\to\pi K, \pi K^{\ast} and \rho K Decays

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    Motivated by the large difference between the direct CP asymmetries ACP(Bπ0K)A_{CP}(B^-\to \pi^0 K^-) and ACP(Bˉ0π+K)A_{CP}(\bar{B}^{0}\to \pi^{+} K^{-}), we combine the up-to-date experimental information on BπKB\to\pi K, πK\pi K^{\ast} and ρK\rho K decays to pursue possible solutions with the nonuniversal ZZ^{\prime} model. Detailed analyses of the relative impacts of different types of couplings are presented in four specific cases. Numerically, we find that the new coupling parameters, ξLL\xi^{LL} and ξLR\xi^{LR} with a common nontrivial new weak phase ϕL86\phi_L\sim-86^{\circ}, which are relevant to the ZZ^{\prime} contributions to the electroweak penguin sector C9\triangle C_9 and C7\triangle C_7, are crucial to the observed "πK\pi K puzzle". Furthermore, they are found to be definitely unequal and opposite in sign. We also find that ACP(Bρ0K)A_{CP}(B^-\to \rho^0 K^-) can put a strong constraint on the new ZZ^{\prime} couplings, which implies the ZZ^{\prime} contributions to the coefficient of QCD penguins operator O3O_3 involving the parameter ζLL\zeta^{LL} required.Comment: 27 pages, 6 figures. References and a note adde

    The effects of non-universal extra dimensions on the radiative lepton flavor decays \mu\to e\gamma and \tau\to \mu\gamma in the two Higgs doublet model

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    We study the effect of non-universal extra dimensions on the branching ratios of the lepton flavor violating processes \mu\to e\gamma and \tau\to \mu\gamma in the general two Higgs doublet model. We observe that these effects are small for a single extra dimension, however, in the case of two extra dimensions there is a considerable enhancement in the additional contributions.Comment: 16 Pages, 9 Figure

    Flow around a cube in a turbulent boundary layer: LES and experiment

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    We present a numerical simulation of flow around a surface mounted cube placed in a turbulent boundary layer which, although representing a typical wind environment, has been specifically tailored to match a series of wind tunnel observations. The simulations were carried out at a Reynolds number, based on the velocity U at the cube height h, of 20,000—large enough that many aspects of the flow are effectively Reynolds number independent. The turbulence intensity was about 18% at the cube height, and the integral length scale was about 0.8 times the cube height h. The Jenson number Je=h/z0, based on the approach flow roughness length z0, was 600, to match the wind tunnel situation. The computational mesh was uniform with a spacing of h/32, aiding rapid convergence of the multigrid solver, and the governing equations were discretised using second-order finite differences within a parallel multiblock environment. The results presented include detailed comparison between measurements and LES computations of both the inflow boundary layer and the flow field around the cube including mean and fluctuating surface pressures. It is concluded that provided properly formulated inflow and surface boundary conditions are used, LES is now a viable tool for use in wind engineering problems concerning flow over isolated bodies. In particular, both mean and fluctuating surface pressures can be obtained with a similar degree of uncertainty as usually associated with wind tunnel modelling

    A slip-based model for the size-dependent effective thermal conductivity of nanowires

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    The heat flux across a nanowire is computed based on the Guyer-Krumhansl equation. Slip conditions with a slip length depending on both temperature and nanowire radius are introduced at the outer boundary. An explicit expression for the effective thermal conductivity is derived and compared to existing models across a given temperature range, providing excellent agreement with experimental data for Si nanowires

    On Neutrino Masses and a Low Breaking Scale of Left-Right Symmetry

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    In left-right symmetric models (LRSM) the light neutrino masses arise from two sources: the seesaw mechanism and a VEV of an SU(2)L_L triplet. If the left-right symmetry breaking, vRv_R, is low, v_R\lsim15\TeV, the contributions to the light neutrino masses from both the seesaw mechanism and the triplet Yukawa couplings are expected to be well above the experimental bounds. We present a minimal LRSM with an additional U(1) symmetry in which the masses induced by the two sources are below the eV scale and the two-fold problem is solved. We further show that, if the U(1) symmetry is also responsible for the lepton flavor structure, the model yields a small mixing angle within the first two lepton generations.Comment: 18 pages references added published versio

    Cryptococcal Meningoencephalitis Presenting as Cerebell itis - A case report -

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    , , We herein report an elderly patient with cryptococcosis in the nervous system who presented with cerebellar dysfunction and showed cerebellar parenchymal lesion with adjacent focal meningeal enhancement on the brain CT and the serial brain MRls. The cerebellar lesion suggests cryptococcal inflammatory reaction or a cerebellar infarction from the arteritis of a branch of the left superior cerebellar artery. This clinical and neuroimaging finding of cerebellitis has not been reported in cryptococcosis. We think cryptococcosis would be included in the differential diagnosis of cerebellitis

    FAS and NF-κB signalling modulate dependence of lung cancers on mutant EGFR

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    Human lung adenocarcinomas with activating mutations in EGFR (epidermal growth factor receptor) often respond to treatment with EGFR tyrosine kinase inhibitors (TKIs), but the magnitude of tumour regression is variable and transient. This heterogeneity in treatment response could result from genetic modifiers that regulate the degree to which tumour cells are dependent on mutant EGFR. Through a pooled RNA interference screen, we show that knockdown of FAS and several components of the NF-κB pathway specifically enhanced cell death induced by the EGFR TKI erlotinib in EGFR-mutant lung cancer cells. Activation of NF-κB through overexpression of c-FLIP or IKK (also known as CFLAR and IKBKB, respectively), or silencing of IκB (also known as NFKBIA), rescued EGFR-mutant lung cancer cells from EGFR TKI treatment. Genetic or pharmacologic inhibition of NF-κB enhanced erlotinib-induced apoptosis in erlotinib-sensitive and erlotinib-resistant EGFR-mutant lung cancer models. Increased expression of the NF-κB inhibitor IκB predicted for improved response and survival in EGFR-mutant lung cancer patients treated with EGFR TKI. These data identify NF-κB as a potential companion drug target, together with EGFR, in EGFR-mutant lung cancers and provide insight into the mechanisms by which tumour cells escape from oncogene dependence

    Experimental Probes of Localized Gravity: On and Off the Wall

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    The phenomenology of the Randall-Sundrum model of localized gravity is analyzed in detail for the two scenarios where the Standard Model (SM) gauge and matter fields are either confined to a TeV scale 3-brane or may propagate in a slice of five dimensional anti-deSitter space. In the latter instance, we derive the interactions of the graviton, gauge, and fermion Kaluza-Klein (KK) states. The resulting phenomenological signatures are shown to be highly dependent on the value of the 5-dimensional fermion mass and differ substantially from the case where the SM fields lie on the TeV-brane. In both scenarios, we examine the collider signatures for direct production of the graviton and gauge KK towers as well as their induced contributions to precision electroweak observables. These direct and indirect signatures are found to play a complementary role in the exploration of the model parameter space. In the case where the SM field content resides on the TeV-brane, we show that the LHC can probe the full parameter space and hence will either discover or exclude this model if the scale of electroweak physics on the 3-brane is less than 10 TeV. We also show that spontaneous electroweak symmetry breaking of the SM must take place on the TeV-brane.Comment: 62 pages, Latex, 22 figure
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