The Impact of Multinational Entry on Domestic Market Structure and R&D

We model the impact of different modes of multinational entry on the choices of domestic firms. Focusing on the competitive effects of foreign presence in the host country we demonstrate that greenfield investment will increase competition only if it is not countered by anti-competitive reactions on the part of the domestic firms. Considering also cross-border mergers and acquisitions the model, thus, provides two alternative explanations for the increase in concentration ratios in industries with mostly horizontal foreign direct investment. Moreover, foreign presence is shown to raise total investment in the local industry at the cost of crowding out domestic R&D.greenfield investment, cross-border mergers and acquisitions, host-country effects, market

Productivity is higher among some service firms when broadband becomes available, but not all. ESRI Research Bulletin 2019/04

Using internet services over broadband connections may help some firms become more productive, generating more output from a given amount of labour and capital equipment. However, there is mixed evidence internationally about how large this benefit has been in practice and which types of firms are most likely to improve their productivity by using these technologies. In this research we examine the effects of broadband availability on the productivity of service sector firms. Some previous studies using region- or country-level data have reported large productivity effects of broadband on services, but it is hard for this type of study to prove that broadband is making firms more productive. For example, their results might partly be explained by factors that both make firms more productive and more likely to use broadband, rather than a causal link from one to the other. Studies using data on firms have tended to find little evidence that there are broad-based gains from this source.2 Our research tries to unpack the service sector to see whether there are identifiable groups of firms that register significant productivity gains after broadband becomes available to them. Knowing more about how large and focused these benefits are should help policymakers predict the likely effects of programmes to bring high-speed broadband to less well-served areas

Quark confinement and color transparency in a gauge-invariant formulation of QCD

We examine a nonlocal interaction that results from expressing the QCD Hamiltonian entirely in terms of gauge-invariant quark and gluon fields. The interaction couples one quark color-charge density to another, much as electric charge densities are coupled to each other by the Coulomb interaction in QED. In QCD, this nonlocal interaction also couples quark color-charge densities to gluonic color. We show how the leading part of the interaction between quark color-charge densities vanishes when the participating quarks are in a color singlet configuration, and that, for singlet configurations, the residual interaction weakens as the size of a packet of quarks shrinks. Because of this effect, color-singlet packets of quarks should experience final state interactions that increase in strength as these packets expand in size. For the case of an SU(2) model of QCD based on the {\em ansatz} that the gauge-invariant gauge field is a hedgehog configuration, we show how the infinite series that represents the nonlocal interaction between quark color-charge densities can be evaluated nonperturbatively, without expanding it term-by-term. We discuss the implications of this model for QCD with SU(3) color and a gauge-invariant gauge field determined by QCD dynamics.Comment: Revtex, 23 pages; contains additional references with brief comments on sam

Carfentrazone-ethyl Pond Dissipation and Efficacy on Floating Plants

Carfentrazone-ethyl (CE) is a reduced risk herbicide that is currently being evaluated for the control of aquatic weeds. Greenhouse trials were conducted to determine efficacy of CE on water hyacinth ( Eichhornia crassipes (Mart.) Solms- Laub.), water lettuce ( Pistia stratiotes L.), salvinia ( Salvinia minima Baker) and landoltia (Landoltia punctata (G. Mey.) Les & D. J. Crawford ) . CE controlled water lettuce, water hyacinth and salvinia at rates less than the maximum proposed use rate of 224 g ha -1 . Water lettuce was the most susceptible to CE with an EC 90 of 26.9 and 33.0 g ha -1 in two separate trials. Water hyacinth EC 90 values were calculated to be 86.2 to 116.3 g ha -1 , and salvinia had a similar susceptibility to water hyacinth with an EC 90 of 79.1 g ha -1 . Landoltia was not adequately controlled at the rates evaluated. In addition, CE was applied to one-half of a 0.08 ha pond located in North Central, Florida to determine dissipation rates in water and hydrosoil when applied at an equivalent rate of 224 g ha -1 . The half-life of CE plus the primary metabolite, CE-chloropropionic acid, was calculated to be 83.0 h from the whole pond, and no residues were detected in water above the limit of quantification (5 μg L -1 ) 168 h after treatment. CE dissipated rapidly from the water column, did not occur in the sediment above the levels of quantification, and in greenhouse studies effectively controlled three species of aquatic weeds at relatively low rates.(PDF contains 6 pages.

Quantum Gauge Equivalence in QED

We discuss gauge transformations in QED coupled to a charged spinor field, and examine whether we can gauge-transform the entire formulation of the theory from one gauge to another, so that not only the gauge and spinor fields, but also the forms of the operator-valued Hamiltonians are transformed. The discussion includes the covariant gauge, in which the gauge condition and Gauss's law are not primary constraints on operator-valued quantities; it also includes the Coulomb gauge, and the spatial axial gauge, in which the constraints are imposed on operator-valued fields by applying the Dirac-Bergmann procedure. We show how to transform the covariant, Coulomb and spatial axial gauges to what we call ``common form,'' in which all particle excitation modes have identical properties. We also show that, once that common form has been reached, QED in different gauges has a common time-evolution operator that defines time-translation for states that represent systems of electrons and photons. By combining gauge transformations with changes of representation from standard to common form, the entire apparatus of a gauge theory can be transformed from one gauge to another.Comment: Contribution for a special issue of Foundations of Physics honoring Fritz Rohrlich; edited by Larry P. Horwitz, Tel-Aviv University, and Alwyn van der Merwe, University of Denver (Plenum Publishing, New York); 40 pages, REVTEX, Preprint UCONN-93-3, 1 figure available upon request from author

Precision Measurements of Stretching and Compression in Fluid Mixing

The mixing of an impurity into a flowing fluid is an important process in many areas of science, including geophysical processes, chemical reactors, and microfluidic devices. In some cases, for example periodic flows, the concepts of nonlinear dynamics provide a deep theoretical basis for understanding mixing. Unfortunately, the building blocks of this theory, i.e. the fixed points and invariant manifolds of the associated Poincare map, have remained inaccessible to direct experimental study, thus limiting the insight that could be obtained. Using precision measurements of tracer particle trajectories in a two-dimensional fluid flow producing chaotic mixing, we directly measure the time-dependent stretching and compression fields. These quantities, previously available only numerically, attain local maxima along lines coinciding with the stable and unstable manifolds, thus revealing the dynamical structures that control mixing. Contours or level sets of a passive impurity field are found to be aligned parallel to the lines of large compression (unstable manifolds) at each instant. This connection appears to persist as the onset of turbulence is approached.Comment: 5 pages, 5 figure

Do Domestic Firms Benefit from Foreign Presence and Competition in Irish Services Sectors? ESRI WP395. July 2011

This paper examines whether domestic firms benefit from foreign competition through imports and from the presence of foreign-owned firms via spillovers in three Irish market-services sectors between 2001 and 2007. Import competition enhances the productivity of domestic firms in two out of three market-services sectors (transport and business activities). The effects from foreign presence are more varied. Foreign presence enhances the productivity of domestic firms in one sector (transport) when using standard output-based measures of productivity. After taking into account the degree of absorptive capacity of the domestic firms this spillover effect only accrues to domestic non-importers. Using input-based measures of productivity, the paper points to adverse effects of foreign presence as it is associated with lower capital-labour ratios and higher part-time-to-full-time employee ratios among domestic firms in wholesale and retail trade

Supersonic STOVL ejector aircraft from a propulsion point of view

A baseline supersonic STOVL ejector aircraft, its propulsion and typical operating modes is described, and important propulsion parameters are identified. Then a number of propulsion system changes are evaluated for improvement of the lift-off performance aft deflection of the ejector jet and heating of the ejector primary air either by burning or using the hot engine core flow. The possibility for cooling the footprint is illustrated for mixing or interchanging the fan and core flows, and in use of a core flow ejector. The application of a new engine concept the turbine bypass engine plus a turbocompressor to supply the ejector primary air, and thrust during takeoff combat are presented