4,409 research outputs found

    Oblique-incidence secondary emission from charged dielectrics

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    Secondary electron emission coefficients were measured on FEP-Teflon for normal and oblique incidence in the presence of a normal electric field. Such measurements require knowledge of the electrostatic environment surrounding the specimen, and they require calculation of particle trajectories such that particle impact parameters can be known. A simulation using a conformal mapping, a Green's integral, and a trajectory generator provides the necessary mathematical support for the measurements, which were made with normal fields of 1.5 and 2.7 kV/mm. When incidence is normal and energy exceeds the critical energy, the coefficient is given by (V sub 0/V) to the .58 power, and for oblique incidence this expression may be divided by the cosine of the angle. The parameter V sub 0 is a function of normal field

    Balancing Efficiency, Equity, and Voice in Workplace Resolution Procedures

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    Systems for resolving workplace disputes are very important to workers and firms, and have been the subject of much debate. In the United States, traditional unionized grievance procedures, emerging nonunion dispute resolution systems, and the court-based system for resolving employment law disputes have all been criticized. Much of the existing debate on workplace dispute resolution, however, has been atheoretical, with a focus on techniques of dispute resolution rather than the goals of the system. What is missing from the debate are fundamental standards for comparing and evaluating dispute resolutions systems. In this paper, we develop efficiency, equity, and voice as these standards. Unionized, nonunion, and employment law procedures are then evaluated against these three standards.

    International Rent Sharing in Multinational Firms

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    We use a unique firm-level panel data set of multinational parents and their foreign affiliates to analyze whether profits are shared across borders within multinational firms. Using both fixed-effects and generalized method-of-moments estimators, affiliate wage levels are estimated to respond to both and parent profitability. The elasticity of affiliate wages to parent profits per worker is approximately 0.03, which can explain over 20 percent of the observed variation in affiliate wages. These results reveal a previously ignored aspect of labor market rent sharing. They also reveal an important micro-level linkage with potential macro-level implications. International rent sharing can transmit economic conditions across national borders, and can thereby provide an implicit cross-country risk-sharing mechanism.

    Wages and International Rent Sharing in Multinational Firms

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    We use a unique firm-level panel data set of multinational parents and their foreign affiliates to analyze whether profits are shared across borders within multinational firms. Using both fixed-effects and generalized method-of-moments estimators, affiliate wage levels are estimated to respond to both affiliate and parent profitability. The elasticity of affiliate wages to parent profits per worker is approximately 0.03, which can explain over 20 percent of the observed variation in affiliate wages. These results reveal a previously ignored aspect of labor-market rent sharing. They also reveal an important micro-level linkage with potential macro-level implications. International rent sharing can transmit economic conditions across national borders, and can thereby provide an implicit cross-country risk-sharing mechanism.Wages, Profit Sharing, Multinational Firms

    International Rent Sharing in Multinational Firms

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    We use a unique firm-level panel data set of multinational parents and their foreign affiliates to analyze whether profits are shared across borders within multinational firms. Using both fixed-effects and generalized method-of-moments estimators, affiliate wage levels are estimated to respond to both affiliate and parent profitability. The elasticity of affiliate wages to parent profits per worker is approximately 0.03, which can explain over 20 percent of the observed variation in affiliate wages. These results reveal a previously ignored aspect of labor-market rent sharing. They also reveal an important micro-level linkage with potential macro-level implications. International rent sharing can transmit economic conditions across national borders, and can thereby provide an implicit cross-country risk-sharing mechanism.

    Multilayered folding with voids

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    In the deformation of layered materials such as geological strata, or stacks of paper, mechanical properties compete with the geometry of layering. Smooth, rounded corners lead to voids between the layers, while close packing of the layers results in geometrically-induced curvature singularities. When voids are penalized by external pressure, the system is forced to trade off these competing effects, leading to sometimes striking periodic patterns. In this paper we construct a simple model of geometrically nonlinear multi-layered structures under axial loading and pressure confinement, with non-interpenetration conditions separating the layers. Energy minimizers are characterized as solutions of a set of fourth-order nonlinear differential equations with contact-force Lagrange multipliers, or equivalently of a fourth-order free-boundary problem. We numerically investigate the solutions of this free boundary problem, and compare them with the periodic solutions observed experimentally

    Blow-up in a System of Partial Differential Equations with Conserved First Integral. Part II: Problems with Convection

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    A reaction-diffusion-convection equation with a nonlocal term is studied; the nonlocal operator acts to conserve the spatial integral of the unknown function as time evolves. The equations are parameterised by µ, and for µ = 1 the equation arises as a similarity solution of the Navier-Stokes equations and the nonlocal term plays the role of pressure. For µ = 0, the equation is a nonlocal reaction-diffusion problem. The aim of the paper is to determine for which values of the parameter µ blow-up occurs and to study its form. In particular, interest is focused on the three cases µ 1/2, and µ → 1. It is observed that, for any 0 ≤ µ ≤ 1/2, nonuniform global blow-up occurs; if 1/2 < µ < 1, then the blow-up is global and uniform, while for µ = 1 (the Navier-Stokes equations) there are exact solutions with initial data of arbitrarily large L_∞, L_2, and H^1 norms that decay to zero. Furthermore, one of these exact solutions is proved to be nonlinearly stable in L_2 for arbitrarily large supremum norm. An understanding of this transition from blow-up behaviour to decay behaviour is achieved by a combination of analysis, asymptotics, and numerical techniques

    miR-9 Acts as an OncomiR in Prostate Cancer through Multiple Pathways That Drive Tumour Progression and Metastasis

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    Identification of dysregulated microRNAs (miRNAs) in prostate cancer is critical not only for diagnosis, but also differentiation between the aggressive and indolent forms of the disease. miR-9 was identified as an oncomiR through both miRNA panel RT-qPCR as well as high-throughput sequencing analysis of the human P69 prostate cell line as compared to its highly tumorigenic and metastatic subline M12, and found to be consistently upregulated in other prostate cell lines including DU-145 and PC3. While miR-9 has been characterized as dysregulated either as an oncomiR or tumour suppressor in a variety of other cancers including breast, ovarian, and nasopharyngeal carcinomas, it has not been previously evaluated and proven as an oncomiR in prostate cancer. miR-9 was confirmed an oncomiR when found to be overexpressed in tumour tissue as compared to adjacent benign glandular epithelium through laser-capture microdissection of radical prostatectomy biopsies. Inhibition of miR-9 resulted in reduced migratory and invasive potential of the M12 cell line, and reduced tumour growth and metastases in male athymic nude mice. Analysis showed that miR-9 targets e-cadherin and suppressor of cytokine signalling 5 (SOCS5), but not NF-ĸB mRNA. Expression of these proteins was shown to be affected by modulation in expression of miR-9

    Interplay of Mre11 Nuclease with Dna2 plus Sgs1 in Rad51-Dependent Recombinational Repair

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    The Mre11/Rad50/Xrs2 complex initiates IR repair by binding to the end of a double-strand break, resulting in 5′ to 3′ exonuclease degradation creating a single-stranded 3′ overhang competent for strand invasion into the unbroken chromosome. The nuclease(s) involved are not well understood. Mre11 encodes a nuclease, but it has 3′ to 5′, rather than 5′ to 3′ activity. Furthermore, mutations that inactivate only the nuclease activity of Mre11 but not its other repair functions, mre11-D56N and mre11-H125N, are resistant to IR. This suggests that another nuclease can catalyze 5′ to 3′ degradation. One candidate nuclease that has not been tested to date because it is encoded by an essential gene is the Dna2 helicase/nuclease. We recently reported the ability to suppress the lethality of a dna2Δ with a pif1Δ. The dna2Δ pif1Δ mutant is IR-resistant. We have determined that dna2Δ pif1Δ mre11-D56N and dna2Δ pif1Δ mre11-H125N strains are equally as sensitive to IR as mre11Δ strains, suggesting that in the absence of Dna2, Mre11 nuclease carries out repair. The dna2Δ pif1Δ mre11-D56N triple mutant is complemented by plasmids expressing Mre11, Dna2 or dna2K1080E, a mutant with defective helicase and functional nuclease, demonstrating that the nuclease of Dna2 compensates for the absence of Mre11 nuclease in IR repair, presumably in 5′ to 3′ degradation at DSB ends. We further show that sgs1Δ mre11-H125N, but not sgs1Δ, is very sensitive to IR, implicating the Sgs1 helicase in the Dna2-mediated pathway

    Extraction of the Axial Nucleon Form Factor from Neutrino Experiments on Deuterium

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    We present new parameterizations of vector and axial nucleon form factors. We maintain an excellent descriptions of the form factors at low momentum transfers (Q2Q^2), where the spatial structure of the nucleon is important, and use the Nachtman scaling variable ξ\xi to relate elastic and inelastic form factors and impose quark-hadron duality constraints at high Q2Q^2 where the quark structure dominates. We use the new vector form factors to re-extract updated values of the axial form factor from \numu experiments on deuterium. We obtain an updated world average value from \numud, \numubarH and pion electroproduction experiments of MAM_{A} = 1.014±0.014GeV/c21.014 \pm 0.014 GeV/c^2. Our parameterizations are useful in modeling ν\nu interactions at low energies (e.g. for \numu oscillations experiments). The predictions for high Q2Q^2 can be tested in the next generation electron and \numu scattering experiments.Comment: Presented by A. Bodek at the European Physical Society Meeting, EPS2007, Manchester, England, July 2007, 4 pages, 2 figure
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