Search results for "METODI"
showing 10 items of 940 documents
Non-perturbative renormalisation of left left four-fermion operators with Neuberger fermions
2006
We outline a general strategy for the non-perturbative renormalisation of composite operators in discretisations based on Neuberger fermions, via a matching to results obtained with Wilson-type fermions. As an application, we consider the renormalisation of the four-quark operators entering the Delta S=1 and Delta S=2 effective Hamiltonians. Our results are an essential ingredient for the determination of the low-energy constants governing non-leptonic kaon decays.
Nonperturbative renormalization of quark bilinears
1998
We compute non-perturbatively the renormalization constants of quark bilinears on the lattice in the quenched approximation at three values of the coupling beta=6/g_0^2=6.0,6.2,6.4 using both the Wilson and the tree-level improved SW-Clover fermion action. We perform a Renormalization Group analysis at the next-to-next-to-leading order and compute Renormalization Group invariant values for the constants. The results are applied to obtain a fully non-perturbative estimate of the vector and pseudoscalar decay constants.
Light Quenched Hadron Spectrum and Decay Constants on different Lattices
1997
In this paper we study O(2000) (quenched) lattice configurations from the APE collaboration, for different lattice volumes and for 6.0 \le beta \le 6.4 using both the Wilson and the SW-Clover fermion actions. We determine the light hadronic spectrum and meson decay constants and study the mesonic dispersion relation. We extract the hadronic variable J and the strange quark mass in the continuum at the next-to-leading order obtaining m_s^{MSbar}(mu=2 GeV) = 122 +/- 20 MeV. A study is made of their dependence on lattice spacing. We implement a newly developed technique to extract the inverse lattice spacing using data at the simulated values of the quark mass (i.e. at masses around the strang…
Kaon mixing beyond the SM from N-f=2 tmQCD and model independent constraints from the UTA
2013
We present the first unquenched, continuum limit, lattice QCD results for the matrix elements of the operators describing neutral kaon oscillations in extensions of the Standard Model. Owing to the accuracy of our calculation on Delta S = 2 weak Hamiltonian matrix elements, we are able to provide a refined Unitarity Triangle analysis improving the bounds coming from model independent constraints on New Physics. In our non-perturbative computation we use a combination of N-f = 2 maximally twisted sea quarks and Osterwalder-Seiler valence quarks in order to achieve both O(a)-improvement and continuum-like renormalization properties for the relevant four-fermion operators. The calculation of t…
B-physics computations from Nf=2 tmQCD
2013
We present an accurate lattice QCD computation of the b-quark mass, the B and Bs decay constants, the B-mixing bag-parameters for the full four-fermion operator basis, as well as estimates for \xi and f_{Bq}\sqrt{B_q} extrapolated to the continuum limit and the physical pion mass. We have used Nf = 2 dynamical quark gauge configurations at four values of the lattice spacing generated by ETMC. Extrapolation in the heavy quark mass from the charm to the bottom quark region has been carried out using ratios of physical quantities computed at nearby quark masses, having an exactly known infinite mass limit.
Ritorno al quartiere
2011
Oggetto di analisi considerato ormai desueto, in un’epoca di reti virtuali e di social networks, il quartiere invece conta ancora molto nella vita quotidiana. Non bisogna identificare il quartiere con stili di vita tradizionali, propri di un mondo contadino, o con un modello di sviluppo ormai anacronistico. Il quartiere è invece la risposta a uno stile di vita sempre più individualistico e anti-comunitario.
A new method to evaluate the influence of the glenosphere positioning on stability and range of motion of a reverse shoulder prosthesis
2019
Abstract Purpose Shoulder instability and reduced range of motion are two common complications of a total reverse shoulder arthroplasty. In this work, a new approach is proposed to estimate how the glenoid component positioning can influence the stability and the range of motion of a reverse shoulder prosthesis. Materials and methods A standard reverse shoulder prosthesis has been analysed. To perform virtual simulation of the shoulder-prosthesis assembly, all the components of the prosthesis have been acquired via a 3D laser scanner and the solid models of the shoulder bones have been reconstructed through CT images. Loads on the shoulder joint have been estimated using anatomical models d…
The relationship between motor timing, reaction time and academic achievements in primary school children.
2017
Aim: Recent studies have reported a correlation between motor skills and school performance, which is different according to the type of motor ability or academic subject examined (Fernandes et al, 2016; Bellafiore et al., 2016). The aim of this study was to analyze the relationship between motor timing, reaction time and achievements in mathematics and Italian in sedentary and active children. Methods: Seventy-eight children (8.55±1.43 years old, 28.93±5.74 kg weight, 126.54±4.74 cm height and 19.30±2.62 kg/m2 BMI) were randomly recruited by a primary school of Palermo, 68% of them practiced a sport outside the academic hours. The motor timing was measured with the finger and foot tapping …
Effects of a physical education program on the development of early literacy abilities in preschool children
2016
Introduction Several studies showed a relationship between physical activity and cognition in school-aged children (Carson et al 2015). The aim of this study was to analyse whether the amount and frequency of a physical education (PE) program affected the early reading and writing skills in preschool children. Methods This study involved 189 children (age: 4.62 ± 0.97 years; height: 107.83 ± 7.82 cm, body weight: 19.84 ± 4.95 kg) of 8 Palermo kindergartens who were randomly divided in a control group (C, n= 29), a 1-intervention group (I-1, n= 120) and a 2-intervention group (I-2, n= 40). I-1 and I-2 children performed a PE program of 16-week length for 4 and 10 hours/week, respectively (to…
Pricing Reinsurance Contracts
2011
Pricing and hedging insurance contracts is hard to perform if we subscribe to the hypotheses of the celebrated Black and Scholes model. Incomplete market models allow for the relaxation of hypotheses that are unrealistic for insurance and reinsurance contracts. One such assumption is the tradeability of the underlying asset. To overcome this drawback, we propose in this chapter a stochastic programming model leading to a superhedging portfolio whose final value is at least equal to the insurance final liability. A simple model extension, furthermore, is shown to be sufficient to determine an optimal reinsurance protection for the insurer: we propose a conditional value at risk (VaR) model p…