293 research outputs found

    Conflicts of Jurisdiction in the Antitrust Field: The Example of Export Cartels

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    Förbehandling av bioslam för ökad biogasproduktion Eftersom bioslam från aktivslamsteget i reningsprocessen ger en lägre metanproduktion än primärslam bör förbehandlingen ske på bioslam. Effekten av olika förbehandlingsmetoder är dock svårbedömd och ofta erhålls inget positivt energiutbyte då energin av ökad produktion av biogas kan vara mindre än tillförd energi vid behandlingen. Vissa förbehandlingsmetoder som ozonering kan vid överdosering oxidera substrat och ge minskad biogasproduktion   Litteraturstudien kompletterades med mätning av biometanpotential efter förbehandling av bioslam (Khayi, 2014). Som förbehandlingsmetoder valdes frysning (djupfryst och lättfryst) och uppvärmning. Vid 35 dagars rötning producerade djupfryst slam 221 Nml CH4/g VS, lättfryst 115 Nml CH4/g VS, det uppvärmt 181 Nml CH4/g VS och det obehandlade (referens) 148 Nml CH4/g VS (Nml, normalmilliliter är gasvolym omräknad till en atmosfärs tryck). Djupfrysning och uppvärmning ökade biogasproduktionen medan lättfrysning gav minskad biogasproduktion.   Uppgradering av biogas Vid uppgradering separeras koldioxid från biogasen varvid metangas erhålles.  Uppgradering kan ske genom att koldioxiden absorberas av ett fast (PSA-teknik med zeoliter eller aktivt kol) eller flytande medium (vattenskrubber, polyetylenglykol eller monoetanolamin) eller med membranteknik. Investeringskostnaden för uppgradering är starkt beroende av storleken på anläggningen snarare än av vilken teknik som används, men vid små är investeringskostnaden för membranteknik något lägre.   Genom intern metananrikning i rötkammaren kan metanhalten i den producerade biogasen ökas. Detta åstadkommes genom att koldioxid avdrivs från slam som sedan återförs till rötkammaren.QC 20140902</p

    The Role of National Antitrust Laws in the Promotion of International Competition

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    Professor Rahl\u27s international antitrust challenge is a first-class, pocket-sized introduction to a debate that has run for decades and yet shows no signs of exhaustion. The piece echoes many of the themes of Professor Rahl\u27s important 1974 Cornell article, while bringing new freshness and vigor to the problem. His challenge demonstrates, in a few simple pages, that the scores of books and hundreds of articles of the last fifteen years have still not resolved key policy questions on the role of national antitrust laws in international commerce

    The Role of National Antitrust Laws in the Promotion of International Competition

    Get PDF
    Professor Rahl\u27s international antitrust challenge is a first-class, pocket-sized introduction to a debate that has run for decades and yet shows no signs of exhaustion. The piece echoes many of the themes of Professor Rahl\u27s important 1974 Cornell article, while bringing new freshness and vigor to the problem. His challenge demonstrates, in a few simple pages, that the scores of books and hundreds of articles of the last fifteen years have still not resolved key policy questions on the role of national antitrust laws in international commerce

    Size-resolved aerosol and cloud condensation nuclei (CCN) properties in the remote marine South China Sea - Part 1: Observations and source classification

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    Abstract. Ship-based measurements of aerosol and cloud condensation nuclei (CCN) properties are presented for 2 weeks of observations in remote marine regions of the South China Sea/East Sea during the southwestern monsoon (SWM) season. Smoke from extensive biomass burning throughout the Maritime Continent advected into this region during the SWM, where it was mixed with anthropogenic continental pollution and emissions from heavy shipping activities. Eight aerosol types were identified using a k-means cluster analysis with data from a size-resolved CCN characterization system. Interpretation of the clusters was supplemented by additional onboard aerosol and meteorological measurements, satellite, and model products for the region. A typical bimodal marine boundary layer background aerosol population was identified and observed mixing with accumulation mode aerosol from other sources, primarily smoke from fires in Borneo and Sumatra. Hygroscopicity was assessed using the κ parameter and was found to average 0.40 for samples dominated by aged accumulation mode smoke; 0.65 for accumulation mode marine aerosol; 0.60 in an anthropogenic aerosol plume; and 0.22 during a short period that was characterized by elevated levels of volatile organic compounds not associated with biomass burning impacts. As a special subset of the background marine aerosol, clean air masses substantially scrubbed of particles were observed following heavy precipitation or the passage of squall lines, with changes in observed aerosol properties occurring on the order of minutes. Average CN number concentrations, size distributions, and κ values are reported for each population type, along with CCN number concentrations for particles that activated at supersaturations between 0.14 and 0.85 %

    Measuring the Weak Phase gamma in Color Allowed B->DKpi Decays

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    We present a method to measure the weak phase gamma in the three-body decay of charged B mesons to the final states D K pi0. These decays are mediated by interfering amplitudes which are color-allowed and hence relatively large. As a result, large CP violation effects that could be observed with high statistical significance are possible. In addition, the three-body decay helps resolve discrete ambiguities that are usually present in measurements of the weak phase. The experimental implications of conducting these measurements with three-body decays are discussed, and the sensitivity of the method is evaluated using a simulation.Comment: 18 pages, LaTex, 15 eps and ps figure

    Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study - Part 2: Philippine receptor observations of fine-scale aerosol behavior

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    Abstract. The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3–12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model. Indeed, the Navy Aerosol Analysis and Prediction System (NAAPS) simulations captured longer period aerosol events quite well but largely failed to capture the timing of high-frequency phenomena. Ultimately, the research findings of these cruises demonstrate the real world challenges of satellite-based missions, significant aerosol life cycle questions such as those the future Aerosol/Clouds/Ecosystems (ACE) will investigate, and the importance of small-scale phenomena such as sea breezes, squall lines, and nucleation events embedded within SWM patterns in dominating aerosol life cycle and potential relationships to clouds

    Challenges of Profile Likelihood Evaluation in Multi-Dimensional SUSY Scans

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    Statistical inference of the fundamental parameters of supersymmetric theories is a challenging and active endeavor. Several sophisticated algorithms have been employed to this end. While Markov-Chain Monte Carlo (MCMC) and nested sampling techniques are geared towards Bayesian inference, they have also been used to estimate frequentist confidence intervals based on the profile likelihood ratio. We investigate the performance and appropriate configuration of MultiNest, a nested sampling based algorithm, when used for profile likelihood-based analyses both on toy models and on the parameter space of the Constrained MSSM. We find that while the standard configuration is appropriate for an accurate reconstruction of the Bayesian posterior, the profile likelihood is poorly approximated. We identify a more appropriate MultiNest configuration for profile likelihood analyses, which gives an excellent exploration of the profile likelihood (albeit at a larger computational cost), including the identification of the global maximum likelihood value. We conclude that with the appropriate configuration MultiNest is a suitable tool for profile likelihood studies, indicating previous claims to the contrary are not well founded.Comment: 21 pages, 9 figures, 1 table; minor changes following referee report. Matches version accepted by JHE

    Observations of Milky Way Dwarf Spheroidal galaxies with the Fermi-LAT detector and constraints on Dark Matter models

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    We report on the observations of 14 dwarf spheroidal galaxies with the Fermi Gamma-Ray Space Telescope taken during the first 11 months of survey mode operations. The Fermi telescope provides a new opportunity to test particle dark matter models through the expected gamma-ray emission produced by pair annihilation of weakly interacting massive particles (WIMPs). Local Group dwarf spheroidal galaxies, the largest galactic substructures predicted by the cold dark matter scenario, are attractive targets for such indirect searches for dark matter because they are nearby and among the most extreme dark matter dominated environments. No significant gamma-ray emission was detected above 100 MeV from the candidate dwarf galaxies. We determine upper limits to the gamma-ray flux assuming both power-law spectra and representative spectra from WIMP annihilation. The resulting integral flux above 100 MeV is constrained to be at a level below around 10^-9 photons cm^-2 s^-1. Using recent stellar kinematic data, the gamma-ray flux limits are combined with improved determinations of the dark matter density profile in 8 of the 14 candidate dwarfs to place limits on the pair annihilation cross-section of WIMPs in several widely studied extensions of the standard model. With the present data, we are able to rule out large parts of the parameter space where the thermal relic density is below the observed cosmological dark matter density and WIMPs (neutralinos here) are dominantly produced non-thermally, e.g. in models where supersymmetry breaking occurs via anomaly mediation. The gamma-ray limits presented here also constrain some WIMP models proposed to explain the Fermi and PAMELA e^+e^- data, including low-mass wino-like neutralinos and models with TeV masses pair-annihilating into muon-antimuon pairs. (Abridged)Comment: 25 pages, 4 figures, accepted to ApJ, Corresponding authors: J. Cohen-Tanugi, C. Farnier, T.E. Jeltema, E. Nuss, and S. Profum
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