Dispersion relation approach to the anomaly in 2 dimensions

We calculate the chiral anomaly in 2 dimensions within a dispersion relation approach and we compare its features with then-dimensional regularization scheme.Supported by Fonds zur Förderung der wissenschaftlichen Forschung in Österreich, Projekt Nr. P8444-TEC     

DYNGA: a general purpose QM-MM-MD program. I. Application to water

We present a general purpose QM-MM-MD engine (DYNGA) designed to test alternative hybrid Hamiltonians geared towards the treatment of problems of interest in structural biology including the use of experimental data constraints. In this first presentation we use DYNGA to explore the behaviour of a traditional QM-MM approach in the treatment of the water—water interaction. We find the potential energy hypersurface for the water dimer computed with the HF 4–31G*/TIP3P hybrid Hamiltonian tends to be too flat. We also explore the effect of using traditional QM-MM techniques on proton wires and conclude there is a need for improvement, possibly addressed by using polarizable force fields.     

ConFlo III - an interface for high precision delta(13)C and delta(15)N analysis with an extended dynamic range

A newly developed interface coupling a CHN combustion device (elemental analyser 'EA') to an isotope ratio mass spectrometer is described and evaluated. The purpose of the device is to extend the dynamic range of delta(13)C and delta(15)N analysis from less than 2 orders of magnitude to more than 3 orders of magnitude. Carbon isotope ratio measurements of atropine as a model compound have been performed analysing between 1 μg to 5 mg C with acceptable to excellent precision (0.6 to 0.06 per thousand, delta-notation). The correction due to the blank signal is critical for sample amounts smaller than 4 μg C. The maximum sample weight is determined by the combustion capacity of the EA. Larger sample amounts are measured using dilution of a small part of the EA effluent with helium. The dilution mechanism works virtually free of isotope fractionation. Copyright 1999 John Wiley & Sons, Ltd.     

PAST AND FUTURE MANAGEMENT OF A COLLAPSED FISHERY: THE BAY OF BISCAY ANCHOVY

Abstract We analyze the efficiency of the international management of the Bay of Biscay anchovy. While a sharing agreement between France and Spain has been in place since 1992, the fish stock collapsed in 2005 and the fishery closed from 2005 to spring 2010. We consider differences in production technologies between both countries and calibrate our model using data from 1987 to 2009. Our results suggest two sources of rent dissipation under the existing sharing agreement: inefficient quota allocation and production inefficiencies due to inflexible national regulations. We discuss several alternatives to improve management.     

Heavy quark-antiquark systems from exponential moments in QCD

We present a detailed analysis for heavy QQ? systems, of how they emerge from the moment procedure of Shifman, Vainshtein and Zakharov. We work with exponential moments which we calculate as limits of power moments presented by Reinders, Rubinstein and Yazaki. Application to charmonium reproduces the results of these authors very well. We are able to treat bottonium states too, and predict the centre-of-mass of the p-states at 9.80 GeV with a bottom on-shell quark mass of $\text{m}\text{?}{}_{\mathrm{<mtext>b</mtext>}}\text{= 4.71}\text{GeV}$. Finally, we show that non-relativistic approximations to the moments, which provide extremely simple formulae, yield results very close to the relativistic moments, for both s- and p-waves.     

Gaussian sum rules in quantum chromodynamics and local duality

A new type of hadronic sum rules are studied in QCD. They correspond to the Gauss-Weierstrass transform of hadronic spectral functions. There is an interesting analogy between these sum rules and the theory of the heat equation which provides a useful framework for formulating quantitatively the notion of local duality. In particular, finite energy sum rules are shown to follow within this framework from the principle of conservation of total heat. Explicit calculations of these sum rules in QCD - from both perturbative and non-perturbative contributions à la Shifman, Vainshtein and Zakharov [1] - have been made in a rather general way which should cover all the practical cases involving light quark systems. A particular case of the -spectral function and its duality to QCD is discussed in detail as an illustration of this new approach.     

Quarkonia in a Gluonic Background Field

We give a systematic treatment of relativistic corrections to a Coulomb system of heavy quarks in a colour background field with a finite correlation time. The relativistic corrections turn out to be significant. Comparison with experiment favors a correlation time of 0.2−0.5 fm. We predict the ³S₁ − ¹S₀ and ³P₁ − ¹P₁ hyperfine splitting.