This article investigates the sources and determinants of output growth of Italian manufacturing firms. Applying stochastic frontier techniques, we decompose output growth into factor accumulation ...and TFP growth for the period 1998–2003. TFP growth is further decomposed into technological change, efficiency change and scale effects. Two key results emerge from the analysis. After confirming that both input accumulation and TFP growth are important in explaining output growth, we show that efficiency change (technological catch-up) is the most significant component of TFP growth in explaining output growth distribution. Furthermore, using a specific model of the asymmetric error component, we find that R&D spillovers, banking efficiency and public infrastructures have statistically significant and economically relevant effects on technological catch-up.
Measurements of the sphericity of primary charged particles in minimum bias proton--proton collisions at sqrt(s)=0.9, 2.76 and 7 TeV with the ALICE detector at the LHC are presented. The observable ...is linearized to be collinear safe and is measured in the plane perpendicular to the beam direction using primary charged tracks with $p_{\rm T}\geq0.5$ GeV/c in $|\eta|\leq0.8$. The mean sphericity as a function of the charged particle multiplicity at mid-rapidity ($N_{\rm ch}$) is reported for events with different $p_{\rm T}$ scales ("soft" and "hard") defined by the transverse momentum of the leading particle. In addition, the mean charged particle transverse momentum versus multiplicity is presented for the different event classes, and the sphericity distributions in bins of multiplicity are presented. The data are compared with calculations of standard Monte Carlo event generators. The transverse sphericity is found to grow with multiplicity at all collision energies, with a steeper rise at low $N_{\rm ch}$, whereas the event generators show the opposite tendency. The combined study of the sphericity and the mean $p_{\rm T}$ with multiplicity indicates that most of the tested event generators produce events with higher multiplicity by generating more back-to-back jets resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with tune PERUGIA-2011 exhibits a noticeable improvement in describing the data, compared to the other tested generators.
The pt-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D0, D+, and D*+ in the rapidity range |y|<0.5, and for transverse momentum 1< pt <12 GeV/c, were ...measured in proton-proton collisions at sqrt(s) = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D0 -> K pi, D+ -> K pi pi, D*+ -> D0 pi, and their charge conjugates, and was performed on a L_{int} = 1.35 nb^{-1} event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at sqrt(s) = 2.76 TeV and at 7 TeV was evaluated by extrapolating to the full phase space the pt-differential production cross sections at sqrt(s) = 2.76 TeV and our previous measurements at sqrt(s) = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cubar D mesons produced in a vector state was also determined.
A
bstract
We present measurements of Underlying Event observables in pp collisions at
$ \sqrt {s} = 0.9 $
and 7TeV. The analysis is performed as a function of the highest charged-particle transverse ...momentum
p
T,LT
in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different
p
T
thresholds: 0.15, 0.5 and 1.0 GeV
/c
. In the Transverse region we observe an increase in the multiplicity of a factor 2–3 between the lower and higher collision energies, depending on the track
p
T
threshold considered. Data are compared to P
ythia
6.4, P
ythia
8.1 and P
hojet
. On average, all models considered underestimate the multiplicity and summed
p
T
in the Transverse region by about 10–30%.
The production of muons from heavy flavour decays is measured at forward rapidity in proton--proton collisions at \sqrt(s) = 7 TeV collected with the ALICE experiment at the LHC. The analysis is ...carried out on a data sample corresponding to an integrated luminosity L_{int} = 16.5 nb^{-1}. The transverse momentum and rapidity differential production cross sections of muons from heavy flavour decays are measured in the rapidity range 2.5 < y < 4, over the transverse momentum range 2 < p_{t} < 12 GeV/c. The results are compared to predictions based on perturbative QCD calculations.
The production of the prompt charm mesons $D^0$, $D^+$, $D^{*+}$, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at the LHC, at a centre-of-mass energy ...$\sqrt{s_{NN}}=2.76$ TeV per nucleon--nucleon collision. The $\pt$-differential production yields in the range $2
The effect of event background fluctuations on charged particle jet reconstruction in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV has been measured with the ALICE experiment. The main sources of ...non-statistical fluctuations are characterized based purely on experimental data with an unbiased method, as well as by using single high p_t particles and simulated jets embedded into real Pb-Pb events and reconstructed with the anti-kt jet finder. The influence of a low transverse momentum cut-off on particles used in the jet reconstruction is quantified by varying the minimum track p_t between 0.15 GeV/c and 2 GeV/c. For embedded jets reconstructed from charged particles with p_t > 0.15 GeV/c, the uncertainty in the reconstructed jet transverse momentum due to the heavy-ion background is measured to be 11.3 GeV/c (standard deviation) for the 10% most central Pb-Pb collisions, slightly larger than the value of 11.0 GeV/c measured using the unbiased method. For a higher particle transverse momentum threshold of 2 GeV/c, which will generate a stronger bias towards hard fragmentation in the jet finding process, the standard deviation of the fluctuations in the reconstructed jet transverse momentum is reduced to 4.8-5.0 GeV/c for the 10% most central events. A non-Gaussian tail of the momentum uncertainty is observed and its impact on the reconstructed jet spectrum is evaluated for varying particle momentum thresholds, by folding the measured fluctuations with steeply falling spectra.
This paper attempts to estimate the impact of pollution abatement investments on the production technology of firms by pursuing two new directions. First, we take advantage of recent econometric ...developments in productivity and efficiency analysis and compare the results obtained with two complementary approaches: parametric stochastic frontier analysis and conditional nonparametric frontier analysis. Second, we focus not only on the average effect but also on its heterogeneity across ?rms and over time and search for potential nonlinearities. We provide new results suggesting that such an effect is heterogeneous both within ?rms and over time and indicating that the effect of pollution abatement investments on the production process is not monotonic. These results have relevant implications both for modeling and for the purposes of advice on environmentally friendly policy. ...French Abstract : Cet article estime l'impact des investissements anti-pollution sur la technologie en suivant deux nouvelles directions. Premierement, il s'inspire de travaux econometriques recents en analyse de la productivite et de l'efficacite et compare les resultats obtenus en utilisant deux approches complementaires : l'approche parametrique des frontieres stochastiques de production et celle non parametrique de frontieres de production. Deuxiemement, l'analyse ne se concentre plus sur le seul comportement moyen mais s'interesse a l'heterogeneite des effets des investissements anti-pollution entre les firmes dans le temps. Une attention particuliere est ainsi donnee a la detection de non linearites. Les resultats empiriques apportent un eclairage nouveau sur ces effets en montrant qu'ils sont heterogenes a la fois entre les firmes et dans le temps et qu'ils ne sont pas monotones. De tels resultats ont une implication en termes non seulement de modelisation des effets des investissements anti-pollution sur la technologie mais aussi de recommandations pour la politique environnementale
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