Chiral Anomalies via Classical and Quantum Functional Methods

In the quantum path integral formulation of a field theory model an anomaly arises when the functional measure is not invariant under a symmetry transformation of the Lagrangian. In this paper, generalizing previous work done on the point particle, we show that even at the classical level we can give a path integral formulation for any field theory model. Since classical mechanics cannot be affected by anomalies, the measure of the classical path integral of a field theory must be invariant under the symmetry. The classical path integral measure contains the fields of the quantum one plus some extra auxiliary ones. So, at the classical level, there must be a sort of "cancellation" of the quantum anomaly between the original fields and the auxiliary ones. In this paper we prove in detail how this occurs for the chiral anomaly.Comment: 26 pages, Latex, misprint fixed, a dedication include

Component metadata management and publication for the grid

There is growing attention to component-oriented software design of Grid applications. Within this framework, applications are built by assembling together independently developed software components. Two main approaches are commonly used to manage, develop and publish software components: one is based on an Interface Description Language (IDL); the other is typical, for instance, of Java and is based on introspection and design conventions. In this paper, we compare them and we propose a third approach that merges the flexibility and fast learning curve of the latter, with the rigor of the former. Our proposal is meant to help the transition towards more modern tools, which is required to develop versatile Grid applications. © 2005 IEEE

Influence of Micro-Structure on Small-Strain Stiffness and Damping of Fine Grained Soil and Effects on Local Site Response

Various experimental studies have shown that soil micro-structure strongly influences the small strain stiffness and damping (G0, D0) of fine-grained soils, as well as their variation with shear strain γ. This dependency, in turn, is expected to influence the local site response. This paper firstly synthesizes the dependency of G0 and D0 on stress state through power relationships, expressed in terms of dimensionless parameters, obtained by fitting a large number of experimental data collected on normally consolidated natural clays. Thereafter, these parameters were correlated to soil micro-structure, by assuming the plasticity index Ip as a representative index property. Subsequently, in order to verify the effect of micro-structure on the local site response, a numerical sensitivity study was carried out on a reference subsoil by introducing in the 1D wave propagation model both non-linearity and hetherogeneity as correlated to variations of Ip

Effect of Cover Crops on Nitrogen Uptake, Soil Water Content and Biomass Production in a Short Rotation Poplar Plantation

The agricultural production of biomass for energy-giving uses is attracting increasing interest particularly in relation to the possibility of reducing the use of fossil fuels and thereby limiting the emission of greenhouse gases. However one of the barriers to wider development of biomass energy sources is the lack of information about the environmental impacts on the landscape of increasing production of biomass crops. In the first growth phases as in the subsequent harvesting stages, the risks of erosion can become considerable due to the absence of any sort of protective canopy. In this case resorting to the use of cover crops can represent a useful agronomic measure since it provides and maintains a suitable ground covering, above all in the winter months when leaf fall exposes the soil to rain action. The aim of the present work was to evaluate some of the agronomic effects of the planting of two different species of cover crops, the legume Trifolium subterraneum L. and the grass Lolium perenne L. in a closely spaced forestry plantation

LP 400-22, A very low-mass and high-velocity white dwarf

We report the identification of LP 400-22 (WD 2234+222) as a very low-mass and high-velocity white dwarf. The ultraviolet GALEX and optical photometric colors and a spectral line analysis of LP 400-22 show this star to have an effective temperature of 11080+/-140 K and a surface gravity of log g = 6.32+/-0.08. Therefore, this is a helium core white dwarf with a mass of 0.17 M_solar. The tangential velocity of this white dwarf is 414+/-43 km/s, making it one of the fastest moving white dwarfs known. We discuss probable evolutionary scenarios for this remarkable object.Comment: accepted for publication in ApJ Letters, made minor correction

Systematic Human Reliability Analysis (SHRA): A New Approach to Evaluate Human Error Probability (HEP) in a Nuclear Plant

Emergency management in industrial plants is a fundamental issue to ensure the safety of operators. The emergency management analyses two fundamental aspects: the system reliability and the human reliability. System reliability is the capability of ensuring the functional properties within a variability of work conditions, considering the possible deviations due to unexpected events. However, system reliability is strongly related to the reliability of its weakest component. The complexity of the processes could generate incidental situations and the worker appears (human reliability) to be the weakest part of the whole system. The complexity of systems influences operator’s ability to take decisions during emergencies. The aim of the present research is to develop a new approach to evaluate human error probability (HEP), called Systematic Human Reliability Analysis (SHRA). The proposed approach considers internal and external factors that affect operator’s ability. The new approach is based on Nuclear Action Reliability Assessment (NARA), Simplified Plant Analysis Risk Human Reliability (SPAR-H) and on the Performance Shaping Factors (PSFs) relationship. The present paper analysed some shortcomings related to literature approaches, especially the limitations of the working time. We estimated HEP, after 8 hours (work standard) during emergency conditions. The correlations between the advantages of these three methodologies allows proposing a HEP analysis during accident scenarios emergencies. SHRA can be used to estimate human reliability during emergencies. SHRA has been applied in a nuclear accident scenario, considering 24 hours of working time. The SHRA results highlight the most important internal and external factors that affect operator’s ability

Parametri di intensità sismica per la stima degli spostamenti permanenti di pendii omogenei

Gli attuali criteri di progettazione in condizioni sismiche si avvalgono di procedure legate alla valutazione della prestazione del sistema espressa in termini di perdite quantificabili (costi di riparazione), di funzionalità o di beni inestimabili (vite umane, beni storico-culturali). In tale ottica il parametro rappresentativo della risposta è correlato attraverso procedure più o meno sofisticate a uno o più parametri che descrivano le caratteristiche del moto sismico. La scelta di tali parametri deve essere effettuata attraverso criteri di efficienza e sufficienza (cfr. p.es. Tothong & Luco, 2007; Luco & Cornell, 2007) inoltre devono poter essere prevedibili attraverso opportune leggi di ricorrenza. In tale ambito, la presente nota propone una applicazione dei criteri citati per la stima della curva di pericolosità degli spostamenti cosismici dei pendii e per la valutazione critica dell’efficienza dei parametri di intensità del moto considerati significativi. In particolare vengono confrontate alcune relazioni indicate nella letteratura nazionale ed internazionale, e viene presentata una relazione che tiene conto dell’intensità di Housner, IH, quale parametro efficace per la stima degli spostamenti. Per la previsione del parametro IH viene proposta, inoltre, una legge di attenuazione in funzione di magnitudo e distanza