Implicazioni di web design per Malesia e Paesi Scandinavi attraverso uno studio interculturale

Persone di culture differenti preferiscono pagine web caratterizzate dai valori della loro cultura e tendono quindi a preferire differenti caratteristiche del sito web a seconda delle loro esigenze in termini di navigazione, sicurezza, informazioni sui prodotti, servizio al cliente, strumenti di shopping e design. Per un’impresa che intende globalizzare il proprio mercato è utile implementare interfacce culturali country specific, ovvero utilizzare pagine web diverse per paesi con culture differenti. Il presente studio si fonda sulle conclusioni proposte da due modelli di analisi culturale, Hall (1976) e Hofstede (1980) e attraverso l’applicazione degli studi di Marcus e Gould (2000) e l’analisi di un campione di siti web commerciali, arriva a definire le linee guida di web design per i Paesi Scandinavi e Malesi

Model independent determination of the shape function for inclusive B decays and of the structure functions in DIS

We present a method to compute, by numerical simulations of lattice QCD, the inclusive semileptonic differential decay rates of heavy hadrons and the structure functions which occur in deep inelastic scattering. The method is based on first principles and does not require any model assumption. It allows the prediction of the differential rate in B semileptonic decays for values of the recoiling hadronic mass W ~ sqrt(M_B Lambda_QCD), which is in the relevant region to extract |V_ub| from the end-point of the lepton spectrum in inclusive decays.Comment: 16 pages, LaTeX fil

Magnetic dipoles and electric currents

We discuss several similarities and differences between the concepts of electric and magnetic dipoles. We then consider the relation between the magnetic dipole and a current loop and show that in the limit of a pointlike circuit, their magnetic fields coincide. The presentation is accessible to undergraduate students with a knowledge of the basic ideas of classical electromagnetism.Comment: 7 pages, 1 figur

Evoluzione dei Fenomeni sismici nell'Appennino centrale

n/

Determination of HQET parameter \lambda_1 from Inclusive Semileptonic B Meson Decay Spectrum

We estimate the heavy quark effective theory parameter \lambda_1 from inclusive semileptonic B-meson decay spectrum. By using recent CLEO double lepton tagging data of B -> X e nu, which shows the lepton momentum as low as 0.6 GeV, we extracted \lambda_1 \sim -0.58 GeV^2. We also derived \bar\Lambda \sim 0.46 GeV and |V_{cb}| = 0.041 \pm 0.002.Comment: 13 pages, 3 figures, LaTeX. Typos are corrected, and added one commen

QCD Corrections and the Endpoint of the Lepton Spectrum in Semileptonic B Decays

Recently, Neubert has suggested that a certain class of nonperturbative corrections dominates the shape of the electron spectrum in the endpoint region of semileptonic $B$ decay. Perturbative QCD corrections are important in the endpoint region. We study the effects of these corrections on Neubert's proposal. The connection between the endpoint of the electron spectrum in semileptonic $B$ decay and the photon spectrum in $b\rightarrow s\gamma$ is outlined.Comment: 18 pages, uses REVTeX, UCSD/PTH 93-38, CALT-68-1910, JHU-TIPAC-930029 (some changes to the discussion of subleading radiative corrections, and minor typos fixed

Decay Constants and Semileptonic Decays of Heavy Mesons in Relativistic Quark Model

We investigate the $B$ and $D$ mesons in the relativistic quark model by applying the variational method with the Gaussian wave function. We calculate the Fermi momentum parameter $p_{_F}$, and obtain $p_{_F} = 0.50 \sim 0.54$ GeV, which is almost independent of the input parameters, $\alpha_s$, $m_b$, $m_c$ and $m_{sp}$. We then calculate the ratio $f_B$/$f_D$, and obtain the result which is larger, by the factor of about 1.3, than $\sqrt{M_D / M_B}$ given by the naive nonrelativistic analogy. This result is in a good agreement with the recent Lattice calculations. We also calculate the ratio $(M_{B^*}-M_{B})$/$(M_{D^*}-M_{D})$. In these calculations the wave function at origin $\psi (0)$ is essential. We also determine $p_{_F}$ by comparing the theoretical prediction of the ACCMM model with the lepton energy spectrum of $B \rightarrow e \nu X$ from the recent ARGUS analysis, and find that $p_{_F}=0.27~\pm~^{0.22}_{0.27}$ GeV, when we use $m_c=1.5$ GeV. However, this experimentally determined value of $p_{_F}$ is strongly dependent on the value of input parameter $m_c$.Comment: 15 pages (Latex) (uses epsfig.sty, 1 figure appended as a uuencoded compressed ps-file

QCD-Based Interpretation of the Lepton Spectrum in Inclusive Bˉ→Xu ℓ νˉ\bar B\to X_u\,\ell\,\bar\nu Decays

We present a QCD-based approach to the endpoint region of the lepton spectrum in $\bar B\to X_u\,\ell\,\bar\nu$ decays. We introduce a genuinely nonperturbative form factor, the shape function, which describes the fall-off of the spectrum close to the endpoint. The moments of this function are related to forward scattering matrix elements of local, higher-dimension operators. We find that nonperturbative effects are dominant over a finite region in the lepton energy spectrum, the width of which is related to the kinetic energy of the $b$-quark inside the $B$ meson. Applications of our method to the extraction of fundamental standard model parameters, among them $V_{ub}$, are discussed in detail.Comment: 17 pages LaTeX, 3 post- script figures available upon request, CERN-TH.7087/9

Inclusive Semileptonic B and Polarized Lambda_b Decays from QCD

The differential decay spectrum $d\Gamma/dE_e dq^2$ for the semileptonic decay of an unpolarized hadron containing a b-quark, and the decay spectrum $d\Gamma/dE_e dq^2 d\!\cos\theta$ for polarized $\Lambda_b$ decay are computed to second order in the $1/m_b$ expansion. Most of the $1/m_b^2$ corrections have a simple physical interpretation, which is discussed in detail. The implications of the results for the determination of $V_{ub}$ are discussed. The decay spectra for semileptonic decay of hadrons containing a c-quark are also given. There is a subtlety in the use of the equations of motion at order $1/m_b^2$ in the heavy quark expansion which is explained.Comment: (46 pages, 8 figs, uses harvmac and uufiles), UCSD/PTH 93-14, CALT-68-1883 (REVISED VERSION: Some typos corrected, and one incorrect paragraph deleted