639 research outputs found
Productivity Growth and Levels in France, Japan, the United Kingdom and the United States in the Twentieth Century.
This study compares labor and total factor productivity (TFP) in France, Japan, the United Kingdom and the United States in the very long (since 1890) and medium (since 1980) runs. During the past century, the United States has overtaken the United Kingdom and become the leading world economy. During the past 25 years, the four countries have also experienced contrasting advances in productivity, in particular as a result of unequal investment in information and communication technology (ICT). The past 120 years have been characterized by: (i) rapid economic growth and large productivity gains in all four countries; (ii) a long decline in productivity in the United Kingdom relative to the United States, and to a lesser extent also relative to France and Japan, a relative decline that was interrupted by the second world war (WW2); (iii) the remarkable catching-up to the United States by France and Japan after WW2, interrupted in the case of Japan during the 1990s. Capital deepening (at least to the extent this can be measured) accounts for a large share of the variations in performance; increasingly during the past 25 years, this has meant ICT capital deepening. However, the capital contribution to growth varies considerably over time and across the four countries, and it is always less important, except in Japan, than the contribution of the various other factors underlying TFP growth, such as, among others, labor skills, technical and organizational changes and knowledge spillovers. Most recently (in 2006), before the current financial world crisis, hourly labor productivity levels were slightly higher in France than in the United States, and noticeably lower in the United Kingdom (by roughly 10%) and even lower in Japan (30%), while TFP levels are very close in France, the United Kingdom and the United States, but much lower (40%) in Japan.Productivity, growth accounting, macro-economic history.
Do product market regulations in upstream sectors curb productivity growth? Panel data evidence for OECD countries
The paper focuses on the influence of upstream competition for productivity outcomes in downstream sectors. This relation is illustrated with a neo-Schumpeterian theoretical model of innovation (Aghion et al., 1997) with market imperfections in the production of intermediate goods. In this context, upstream market imperfections create barriers to competition in downstream markets and upstream producers use their market power to share innovation rents sought by downstream firms. Thus, lack of competition in upstream markets curbs incentives to improve productivity downstream, negatively affecting productivity outcomes. We test this prediction by estimating an error correction model that differentiates the potential downstream effects of lack of upstream competition in situations close and far from the global technological frontier. We measure competition upstream with regulatory burden indicators derived from OECD data on sectoral product market regulation and the industry-level efficiency improvement and the distance to frontier variables by means of a multifactor productivity (MFP) index. Panel regressions are run for 15 OECD countries and 20 sectors over the 1985-2007 period with country, sector and year fixed effects. We find clear evidence that anticompetitive regulations in upstream sectors have curbed MFP growth downstream over the past 15 years. These effects tend to be strongest for observations (i.e. country/sector/period triads) that are close to the global technological frontier. Our results suggest that, measured at the average distance to frontier and average level of anticompetitive regulations, the marginal effect of increasing competition by easing such regulations is to increase MFP growth by between 1 and 1.5 per cent per year in the OECD countries covered by our sample. Our results are robust to changes in the way MFP and the regulatory burden indicators are constructed, as well as to variations in the sample of countries and/or sectors.Productivity, Growth, Regulations, Competition, Catch-up.
Ph.D. research output in STEM: the role of gender and race in supervision
We study whether student-advisor gender and race couples matter for publication productivity of Ph.D. students in South Africa. We consider the sample of all Ph.D.s in STEM graduating between 2000 and 2014, after the recent systematic introduction of doctoral programs in this country. We investigate the joint effects of gender and race for the whole sample and looking separately at the sub-samples of (1) whitewhite; (2) black-black; and (3) black-white student-advisor couples. We find early career productivity differences: while female students publish on average 10% to 20% fewer articles than males, this is true mainly for female students working with a male advisor, not for those working with a female one. These disparities are similar, though more pronounced, when looking at the joint effects of gender and race for the white-white and black-black student-advisor pairs. We also explore whether publication productivity differences change significantly for students with a high, medium, or low âproductivity-profileâ, and find that they are U-shaped. Female students with a high (or low) âproductivity-profileâ studying with female advisors are as productive than male students with a high (or low) âproductivity-profileâ studying with male advisor
Lâ effet de la diffusion des technologies de lâinformation et de la communication (TIC) sur la productivitĂ© par employĂ© en France.
Sum of exit times in series of metastable states in probabilistic cellular automata
Reversible Probabilistic Cellular Automata are a special class
of automata whose stationary behavior is described by Gibbs--like
measures. For those models the dynamics can be trapped for a very
long time in states which are very different from the ones typical
of stationarity.
This phenomenon can be recasted in the framework of metastability
theory which is typical of Statistical Mechanics.
In this paper we consider a model presenting two not degenerate in
energy
metastable states which form a series, in the sense that,
when the dynamics is started at one of them, before reaching
stationarity, the system must necessarily visit the second one.
We discuss a rule for combining the exit times
from each of the metastable states
Order-dependent structure of High Harmonic Wavefronts
The physics of high harmonics has led to the generation of attosecond pulses
and to trains of attosecond pulses. Measurements that confirm the pulse
duration are all performed in the far field. All pulse duration measurements
tacitly assume that both the beam's wavefront and intensity profile are
independent of frequency. However, if one or both are frequency dependent, then
the retrieved pulse duration depends on the location where the measurement is
made. We measure that each harmonic is very close to a Gaussian, but we also
find that both the intensity profile and the beam wavefront depend
significantly on the harmonic order.
Thus, our findings mean that the pulse duration will depend on where the
pulse is observed. Measurement of spectrally resolved wavefronts along with
temporal characterization at one single point in the beam would enable complete
space-time reconstruction of attosecond pulses. Future attosecond science
experiments need not be restricted to spatially averaged observables
The direct evaluation of attosecond chirp from a streaking measurement
We derive an analytical expression, from classical electron trajectories in a
laser field, that relates the breadth of a streaked photoelectron spectrum to
the group-delay dispersion of an isolated attosecond pulse. Based on this
analytical expression, we introduce a simple, efficient and robust procedure to
instantly extract the attosecond pulse's chirp from the streaking measurement.Comment: 4 figure
Financial Factors and Investment in Belgium, France, Germany, and the United Kingdom: A Comparison Using Company Panel Data
Anxiety-like behavior of prenatally stressed rats is associated with a selective reduction of glutamate release in the ventral hippocampus
Abnormalities of synaptic transmission and plasticity in the hippocampus represent an integral part of the altered programming triggered by early life stress. Prenatally restraint stressed (PRS) rats develop long-lasting biochemical and behavioral changes, which are the expression of an anxious/depressive-like phenotype. We report here that PRS rats showed a selective impairment of depolarization- or kainate-stimulated glutamate and 3HD-aspartate release in the ventral hippo campus, a region encoding memories related to stress and emotions. GABA release was un affected in PRS rats. As a consequence of reduced glutamate release, PRS rats were also highly resistant to kainate-induced seizures. Abnormalities of glutamate release were associated with large reductions in the levels of synaptic vesicle-related proteins, such as VAMP (synaptobrevin), syntaxin-1, synaptophysin, synapsin Ia/b and IIa, munc-18, and Rab3A in the ventral hippocampus of PRS rats. Anxiety-like behavior in male PRS (and control) rats was inversely related to the extent of depolarization-evoked glutamate release in the ventral hippocampus. A causal relationship between anxiety-like behavior and reduction in glutamate release was demonstrated usingamixtureofthemGlu2/3 receptor antagonist, LY341495, and the GABAB receptor antagonist, CGP52432, which was shown to amplify depolarization-evoked 3HD-aspartate release in the ventral hippocampus. Bilateral micro infusion of CGP52432 plus LY341495 in the ventral hippocampus abolished anxiety-like behavior in PRS rats. These findings indicate that an impairment of glutamate release in the ventral hippocampus is a key component of the neuro plastic program induced by PRS, and that strategies aimed at enhancing glutamate release in the ventral hippocampus correct the "anxious phenotype" caused by early life stress
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Rationale and design of the Apixaban for the Reduction of Thrombo-Embolism in Patients With Device-Detected Sub-Clinical Atrial Fibrillation (ARTESiA) trial.
BACKGROUND: Device-detected subclinical atrial fibrillation (AF) refers to infrequent, short-lasting, asymptomatic AF that is detected only with long-term continuous monitoring. Subclinical AF is common and associated with an increased risk of stroke; however, the risk of stroke with subclinical AF is lower than for clinical AF, and very few patients with subclinical AF alone have been included in large AF anticoagulation trials. The net benefit of anticoagulation in patients with subclinical AF is unknown. DESIGN: ARTESiA is a prospective, multicenter, double-blind, randomized controlled trial, recruiting patients with subclinical AF detected by an implanted pacemaker, defibrillator, or cardiac monitor, and who have additional risk factors for stroke. Patients with clinical AF documented by surface electrocardiogram will be excluded from the study. Participants will be randomized to receive either apixaban (according to standard AF dosing) or aspirin 81mg daily. The primary outcome is the composite of stroke, transient ischemic attack with diffusion-weighted magnetic resonance imaging evidence of cerebral infarction, and systemic embolism. Approximately 4,000 patients will be enrolled from around 230 clinical sites, with an anticipated mean follow-up of 36months until 248 adjudicated primary outcome events have occurred. SUMMARY: ARTESiA will determine whether oral anticoagulation therapy with apixaban compared with aspirin reduces the risk of stroke or systemic embolism in patients with subclinical AF and additional risk factors
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