293 research outputs found
Conflicts of Jurisdiction in the Antitrust Field: The Example of Export Cartels
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
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
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
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
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
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
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
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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