Speeding Up the Internet: Regulation and Investment in the European Fiber Optic Infrastructure

In this paper, we study how the coexistence of access regulations for legacy (copper) and fiber networks shapes the incentives to invest in fiber-based network infrastructures. To this end, we first develop a theoretical model that extends the existing literature by, among other things, considering alternative firms with proprietary legacy network (e.g., cable operators) and the presence of asymmetric mandated access to networks. In the empirical part, we test the theoretical predictions using a novel panel data from 27 EU member states pertaining to the last decade. Our main finding is that, in line with the theoretical results, stricter access regulations (i.e., a decrease in access price to legacy network and the adoption of fiber regulation) decrease the incumbent operators' fiber investments. The estimated magnitude of these effects is economically significant. On the other hand, cable operators, who are responsible for the largest share of investments in fiber, are not affected by access regulation. Our paper thus provides policy insights for the on-going revision of the EU regulation framework for the electronic communications industry

Static or Dynamic Efficiency: Horizontal Merger Effects in the Wireless Telecommunications Industry

This paper studies five mergers in the European wireless telecommunication industry and analyzes their impact on prices and capital expenditures of both merging carriers and their rivals. We find substantial heterogeneity in the relationship between increases in concentration and carriers' prices. The specifics of each merger case clearly matter. Moreover, we find a positive correlation between the price and the investment effect; when the prices after a merger increase (decrease), the investments increase (decrease) too. Thus, we document a trade-off between static and dynamic efficiency of mergers

Color Transparency via Coherent Exclusive rho Production

We examine the potential of the COMPASS experiment at CERN to study color transparency via exclusive coherent vector meson production in hard muon-nucleus scattering. It is demonstrated that COMPASS has high sensitivity to test this important prediction of perturbative QCD.Comment: Feasibility study for COMPASS collaboration, 3 pages, no figures, 1 table. This contribution is based on talk presented at the Workshop on Spin Physics, Trento, Italy, July 2001. The conference www site is http://ECTstar.ect.it/contents.html The proceedings of the workshop will be published as a special issue of Nuclear Physics B (proc suppl), eds. S Bass, A De Roeck and A Deshpande. A more complete 26 page feasibility study with 7 figures and 3 tables is available as A. Sandacz et al., hep-ex/0106076 Revision of 26 Sept. for Ref. 11 modificatio

Astrophysical Uncertainties in the Cosmic Ray Electron and Positron Spectrum From Annihilating Dark Matter

In recent years, a number of experiments have been conducted with the goal of studying cosmic rays at GeV to TeV energies. This is a particularly interesting regime from the perspective of indirect dark matter detection. To draw reliable conclusions regarding dark matter from cosmic ray measurements, however, it is important to first understand the propagation of cosmic rays through the magnetic and radiation fields of the Milky Way. In this paper, we constrain the characteristics of the cosmic ray propagation model through comparison with observational inputs, including recent data from the CREAM experiment, and use these constraints to estimate the corresponding uncertainties in the spectrum of cosmic ray electrons and positrons from dark matter particles annihilating in the halo of the Milky Way.Comment: 21 pages, 9 figure

A Recurrent Silent Mutation Implicates fecA in Ethanol Tolerance by Escherichia coli.

BACKGROUND: An issue associated with efficient bioethanol production is the fact that the desired product is toxic to the biocatalyst. Among other effects, ethanol has previously been found to influence the membrane of E. coli in a dose-dependent manner and induce changes in the lipid composition of the plasma membrane. We describe here the characterization of a collection of ethanol-tolerant strains derived from the ethanologenic Escherichia coli strain FBR5. RESULTS: Membrane permeability assays indicate that many of the strains in the collection have alterations in membrane permeability and/or responsiveness of the membrane to environmental changes such as temperature shifts or ethanol exposure. However, analysis of the strains by gas chromatography and mass spectrometry revealed no qualitative changes in the acyl chain composition of membrane lipids in response to ethanol or temperature. To determine whether these strains contain any mutations that might contribute to ethanol tolerance or changes in membrane permeability, we sequenced the entire genome of each strain. Unexpectedly, none of the strains displayed mutations in genes known to control membrane lipid synthesis, and a few strains carried no mutations at all. Interestingly, we found that four independently-isolated strains acquired an identical C → A (V244 V) silent mutation in the ferric citrate transporter gene fecA. Further, we demonstrated that either a deletion of fecA or over-expression of fecA can confer increased ethanol survival, suggesting that any misregulation of fecA expression affects the cellular response to ethanol. CONCLUSIONS: The fact that no mutations were observed in several ethanol-tolerant strains suggested that epigenetic mechanisms play a role in E. coli ethanol tolerance and membrane permeability. Our data also represent the first direct phenotypic evidence that the fecA gene plays a role in ethanol tolerance. We propose that the recurring silent mutation may exert an effect on phenotype by altering RNA-mediated regulation of fecA expression

Sparticle masses in deflected mirage mediation

We discuss the sparticle mass patterns that can be realized in deflected mirage mediation scenario of supersymmetry breaking, in which the moduli, anomaly, and gauge mediations all contribute to the MSSM soft parameters. Analytic expression of low energy soft parameters and also the sfermion mass sum rules are derived, which can be used to interpret the experimentally measured sparticle masses within the framework of the most general mixed moduli-gauge-anomaly mediation. Phenomenological aspects of some specific examples are also discussed.Comment: 43 pages, 17 figures, references adde

The Leptonic Higgs as a Messenger of Dark Matter

We propose that the leptonic cosmic ray signals seen by PAMELA and ATIC result from the annihilation or decay of dark matter particles via states of a leptonic Higgs doublet to $\tau$ leptons, linking cosmic ray signals of dark matter to LHC signals of the Higgs sector. The states of the leptonic Higgs doublet are lighter than about 200 GeV, yielding large $\bar{\tau} \tau$ and $\bar{\tau} \tau \bar{\tau} \tau$ event rates at the LHC. Simple models are given for the dark matter particle and its interactions with the leptonic Higgs, for cosmic ray signals arising from both annihilations and decays in the galactic halo. For the case of annihilations, cosmic photon and neutrino signals are on the verge of discovery.Comment: 34 pages, 9 figures, minor typos corrected, references adde