Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory.

Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy.

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory.

Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.

Ozonation and combined ozone/H2O2, UV/ozone and UV/H2O2 for treatment of fuel oxygenates MTBE, ETBE, TAME, and DIPE from water--a comparison of removal efficiencies.

Methyl tert-butylether (MTBE) used as fuel oxygenate poses problems for water suppliers since it is persistent in the aquatic environment and the removal efficiency by conventional water treatment methods (aeration or activated carbon filtration) is rather low. Substitution by other ether compounds such as ethyl tert-butylether (ETBE), tert-amylmethylether (TAME) or di-isopropylether (DIPE) is discussed, however, their environmental behaviour is similar to that of MTBE. Experiments investigating the elimination efficiency of AOP were carried out in tap water and water from Lake Constance. The elimination efficiency for all treatment processes was found to follow the order: MTBE << TAME approximately equal ETBE < DIPE For all compounds under investigation, neither pure ozonation nor UV irradiation yield a considerable concentration decline. Only the formation of highly reactive OH radicals shows a potential for removing the ethers from water. Therefore the addition of H2O2 in equimolar ratio prior to ozone admixing proved to be quite efficient. The application of combined UV/H2O2 showed good results in all cases; the best concentration decline was achieved with UV/ozone. The rate of elimination of the three substitutes for MTBE (ETBE, TAME and DIPE) is higher in all processes; nevertheless, no complete removal could be achieved. Therefore, from the point of view of water suppliers, the use of other ethers as substitute for MTBE is posing the same problems as MTBE.

Competitive and hindering effects of natural organic matter on the adsorption of MTBE onto activated carbons and zeolites.

Equilibrium and kinetic adsorption of methyl tert-butyl ether (MTBE) onto three coal-based activated carbons, one coconut-based activated carbon, and two zeolites are elucidated in this study. Natural organic matter (NOM) and MTBE competed for the adsorption of activated carbons to different extents. The ideal adsorbed solution theory (IAST) combined with the equivalent background compound (EBC) model can adequately describe the NOM competition and predict the isotherms of MTBE onto the activated carbons. No competitive adsorption was observed for one of the zeolites, mordenite, due to the molecular effect. Besides, the aperture size, and the SiO2/Al2O3 ratio of the zeolite may also play an important role in the adsorption of MTBE from the aqueous phase. The surface diffusion model accurately simulated the transport of MTBE within the adsorbents employed in different water matrices. For all the activated carbons tested, the surface diffusivity of MTBE in natural water was nearly equal to that in deionized water, indicating that no apparently hindering effect occurs. A much slower adsorption kinetic of mordenite in natural water was observed since the opening apertures on mordenite may be appreciably hindered and blocked by NOM.

Compliance with maintenance therapy in a private periodontal practice.

The purpose of this study was to determine patient compliance with suggested maintenance schedules. All patients eligible for maintenance therapy in a private periodontal practice were included. The study covered a period of 8 years. All patients had chronic inflammatory periodontal disease and had been eligible for at least 1 year of maintenance therapy before the close of data collection. A total of 961 patients were studied; only 16% complied with recommended maintenance schedules. Erratic compliance was found in 49% of the patients and 34% never reported for any maintenance therapy.