99,437 research outputs found

    Can a strongly interacting Higgs boson rescue SU(5)?

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    Renormalization group analyses show that the three running gauge coupling constants of the Standard Model do not become equal at any energy scale. These analyses have not included any effects of the Higgs boson's self-interaction. In this paper, I examine whether these effects can modify this conclusion.Comment: 8 pages (plus 4 postscript figures

    Sorption behaviours and transport potentials for selected pharmaceuticals and triclosan in two sterilised soils

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    Purpose: Pharmaceuticals and personal care products (PPCPs) are emerging environmental pollutants, which in addition to direct deposition processes, can find their way into surface soils through the agricultural application of sewage sludge and irrigation practices using contaminated wastewater. Therefore, it is important to assess the extent to which soils are able to retain PPCPs and to prevent their downward migration towards groundwaters. Materials and methods: To further our understanding in this area, batch sorption experiments and artificial rainwater leaching experiments have been performed using five compounds (bezafibrate, carbamazepine, chloramphenicol, diclofenac and triclosan) possessing a range of physicochemical properties in two soils with differing acidities and organic carbon contents. Results and discussion: The determined Koc values for triclosan and diclofenac consistently demonstrated their lower potential mobilities in both soils. The predicted high mobility of chloramphenicol is supported by its efficient leaching potential (89-100%) in both soils whereas bezafibrate, diclofenac and carbamazepine demonstrate slightly lower affinities for the leachate (61-96%) for soil A and are strongly retained (>99%) by soil B. The amount of PPCP in the leachate, the rate of leaching and the depth of soil penetration are explained in terms of the soil characteristics and the properties of the individual PPCPs (such as solubility and pKa) with soil organic content being shown to be a critical factor controlling the ability of a soil to retain a PPCP in the surface layers. Conclusions: The findings contribute to the scientific knowledge required by practitioners and regulators as they consider future sub-soil contamination by PPCPs and subsequent possible threats to groundwater resources and surface water habitats

    Soil mobility of surface applied polyaromatic hydrocarbons in response to simulated rainfall

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    Polyaromatic hydrocarbons (PAHs) are emitted from a variety of sources and can accumulate on and within surface soil layers. To investigate the level of potential risk posed by surface contaminated soils, vertical soil column experiments were conducted to assess the mobility, when leached with simulated rainwater, of six selected PAHs (naphthalene, phenanthrene, fluoranthene, pyrene, benzo(e)pyrene and benzo(ghi)perylene) with contrasting hydrophobic characteristics and molecular weights/sizes. The only PAH found in the leachate within the experimental period of 26 days was naphthalene. The lack of migration of the other applied PAHs were consistent with their low mobilities within the soil columns which generally parallelled their log Koc values. Thus only 2.3% of fluoranthene, 1.8% of pyrene, 0.2% of benzo(e)pyrene and 0.4% of benzo(ghi)perylene were translocated below the surface layer. The PAH distributions in the soil columns followed decreasing power relationships with 90% reductions in the starting levels being shown to occur within a maximum average depth of 0.94 cm compared to an average starting depth of 0.5 cm. A simple predictive model identifies the extensive time periods, in excess of 10 years, required to mobilise 50% of the benzo(e)pyrene and benzo(ghi)perylene from the surface soil layer. Although this reduces to between 2 and 7 years for fluoranthene and pyrene, it is concluded that the possibility of surface applied PAHs reaching and contaminating a groundwater aquifer is unlikely

    Renormalisation of supersymmetric gauge theory in the uneliminated component formalism

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    We show that the renormalisation of the N=1 supersymmetric gauge theory when working in the component formalism, without eliminating auxiliary fields and using a standard covariant gauge, requires a non-linear renormalisation of the auxiliary fields.Comment: 9 pages, including 4 figures. Plain TeX. Uses Harvmac and epsf; reference added and minor changes to Introductio

    A Tale of Two Theories: Quantum Griffiths Effects in Metallic Systems

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    We show that two apparently contradictory theories on the existence of Griffiths-McCoy singularities in magnetic metallic systems [1,2] are in fact mathematically equivalent. We discuss the generic phase diagram of the problem and show that there is a non-universal crossover temperature range T* < T < W where power law behavior (Griffiths-McCoy behavior) is expect. For T<T* power law behavior ceases to exist due to the destruction of quantum effects generated by the dissipation in the metallic environment. We show that T* is an analogue of the Kondo temperature and is controlled by non-universal couplings.Comment: 4 pages, 2 figure

    On the Path-Integral Derivation of the Anomaly for the Hermitian Equivalent of the Complex PTPT-Symmetric Quartic Hamiltonian

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    It can be shown using operator techniques that the non-Hermitian PTPT-symmetric quantum mechanical Hamiltonian with a "wrong-sign" quartic potential −gx4-gx^4 is equivalent to a Hermitian Hamiltonian with a positive quartic potential together with a linear term. A naive derivation of the same result in the path-integral approach misses this linear term. In a recent paper by Bender et al. it was pointed out that this term was in the nature of a parity anomaly and a more careful, discretized treatment of the path integral appeared to reproduce it successfully. However, on re-examination of this derivation we find that a yet more careful treatment is necessary, keeping terms that were ignored in that paper. An alternative, much simpler derivation is given using the additional potential that has been shown to appear whenever a change of variables to curvilinear coordinates is made in a functional integral.Comment: LaTeX, 12 pages, no figure

    Factors influencing the infiltration of pharmaceuticals through soils

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    Pharmaceuticals and personal care products (PPCPs) are emerging environmental contaminants but studies of their environmental fate have focused on their behaviour during wastewater treatment processes. Little is known about the behaviour of PPCPs in soils and this is important to provide an understanding of how these compounds will be distributed during the infiltration processes which occur both naturally and under a number of treatment procedures. In this study four PPCP compounds (bezafibrate, carbamazepine, chloramphenicol and diclofenac) have been selected for investigation to determine their mobility and leaching behaviour in two types of soils. Under experimental conditions, chloramphenicol showed the highest potential to leach through the soils followed by carbamazepine, bezafibrate and diclofenac, which mirrors the order of their increasing organic carbon adsorption coefficients (Koc). The results suggest that ionic strength, pH and soil organic matter (SOM) are notable factors affecting the sorption and therefore the overall fate of pharmaceutical compounds in the soil environment
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