17,337 research outputs found
Productivity in services twenty years on. A review of conceptual and measurement issues and a way forward
Griliches' seminal contribution on "Output measurement in the service sectors" (1992) is now more than twenty years old. The aim of this paper is to review and systematise the scholarship that has been produced since, to identify any step forward in the conceptualisation of service output, the measurement of service productivity and the account of technical change in affecting productivity in services that might have occurred. An agenda for both innovation and service scholars is proposed
Inflation Targets as Focal Points
In a world characterised by noisy information and conflicting signals, no Central Bank is always able to affect private sector expectations. Based on Morris and Shin's model, monetary policy then becomes an information game, in which individuals form their expectations based on all the information that is available to them (public and private). However individual agents also know that ultimately inflation is affected by both the objectives of the Central Bank (and hence the policies it pursues) as well as the average expectation formed by the all agents. They thus need to evaluate both actions. Central to our argument is the way that individuals interpret these actions to form their expectations. We apply Bacharach's methodology to provide a framework for assessing everyone's interpretations. Our contribution is to merge these two models to show that a monetary policy regime that has explicit quantitative objectives may provide individuals with better anchors for expectations to coordinate at. However, that is only true first, if no great shocks are anticipated to hit the economy and second, when all other public information is very unclear thus rendering the inflation target the only clear piece of information. We derive in detail the conditions under which this is true.
Sarda female lambs bred at pasture: growth rate from weaning to reproductive activity
The traditional dairy sheep system in Sardinia presents 2 lambing seasons: in November-December for mature
ewes and in February-March for primiparous. Replacement (20-25% of female lambs) usually came from mature ewes whereas all lambs born in January-February are slaughtered when their market price is low. These lambs could represent part of flock replacement that can integrate the traditional lamb breeding system, and also a flock replacement of ewes that are planned to lamb in late winter to have a continuous milk production all over the year.
The aim of the present work, that represent an aspect of a wider trial, was to determine the suitability to breed this
lambs under grazing condition monitoring their growth rate from weaning to the beginning of reproductive activity.
At the âBonassaiâ research farm an experiment was carried out from March 2004 to May 2005. 51 female Sarda
lambs born from 19/01/2004 to 07/02/2004 (live weight 3.24±0.51 kg; mean±standard deviation) were weaned on
average of 45 days (live weight 12.02±1.52 kg) and weighted monthly. After weaning feeding regimen was based on
grazed forage crops (Lolium multiflorum Lam., Hedysarum coronarium L. and Cichorium intybus L.) and on natural pasture with an average stocking rate of 5.5 head/ha. The supplementation ranged between 0 - 1200 g/head/d of Lucerne and Italian ryegrass hay and 0 - 400 g/head/d of commercial concentrate, depending on herbage on offer.
The amount of hay and concentrate offered during the trial represented 51% of total energetic requirements of lambs. Average lamb daily gain (ADG) during the experimental period resulted 74±11 g head/day. The ADG pattern showed a maximum value 30 days after weaning (139±33 g head/day) and a minimum value in January when herbage availability was low. At the beginning of reproductive activity lambs weighed on average 40.5±3.5 kg and their average body condition score was 3.03±0.12. The trial showed that is possible to breed lambs born in late winter at pasture. However an economic and technical evaluation of differences of these lambs compared to those bred in the traditional system is under evaluation
Semi-Parametric Empirical Best Prediction for small area estimation of unemployment indicators
The Italian National Institute for Statistics regularly provides estimates of
unemployment indicators using data from the Labor Force Survey. However, direct
estimates of unemployment incidence cannot be released for Local Labor Market
Areas. These are unplanned domains defined as clusters of municipalities; many
are out-of-sample areas and the majority is characterized by a small sample
size, which render direct estimates inadequate. The Empirical Best Predictor
represents an appropriate, model-based, alternative. However, for non-Gaussian
responses, its computation and the computation of the analytic approximation to
its Mean Squared Error require the solution of (possibly) multiple integrals
that, generally, have not a closed form. To solve the issue, Monte Carlo
methods and parametric bootstrap are common choices, even though the
computational burden is a non trivial task. In this paper, we propose a
Semi-Parametric Empirical Best Predictor for a (possibly) non-linear mixed
effect model by leaving the distribution of the area-specific random effects
unspecified and estimating it from the observed data. This approach is known to
lead to a discrete mixing distribution which helps avoid unverifiable
parametric assumptions and heavy integral approximations. We also derive a
second-order, bias-corrected, analytic approximation to the corresponding Mean
Squared Error. Finite sample properties of the proposed approach are tested via
a large scale simulation study. Furthermore, the proposal is applied to
unit-level data from the 2012 Italian Labor Force Survey to estimate
unemployment incidence for 611 Local Labor Market Areas using auxiliary
information from administrative registers and the 2011 Census
Stock Market Integration between three CEECs, Russia and the UK
This paper estimates a tri-variate VAR-GARCH(1,1)-in-mean model to examine linkages between the stock markets of three Central and Eastern European countries (CEECs), specifically the Czech Republic, Hungary, and Poland, and both the UK and Russia. The adopted framework allows to analyse interdependence by estimating volatility spillovers, and also contagion by testing for possible shifts in the transmission of volatility following the introduction of the euro and EU accession. Further evidence on possible changes in the transmission mechanism (namely, on whether there is contagion) can be obtained by examining the conditional correlations implied by the estimated model over different time periods. The empirical findings suggest that there is significant co-movement (interdependence) of these CEEC markets with both the Russian and the UK ones. Furthermore, whilst the introduction of the euro has had mixed effects, EU accession has resulted in an increase in volatility spillovers between the three CEECs considered and the UK (contagion).Central and Eastern European countries (CEECs), volatility spillovers, interdependence, contagion, VAR-GARCH-in-mean model
Affective norms for italian words in older adults: Age differences in ratings of valence, arousal and dominance
In line with the dimensional theory of emotional space, we developed affective norms for words rated in terms of valence, arousal and dominance in a group of older adults to complete the adaptation of the Affective Norms for English Words (ANEW) for Italian and to aid research on aging. Here, as in the original Italian ANEW database, participants evaluated valence, arousal, and dominance by means of the Self-Assessment Manikin (SAM) in a paper-and-pencil procedure. We observed high split-half reliabilities within the older sample and high correlations with the affective ratings of previous research, especially for valence, suggesting that there is large agreement among older adults within and across-languages. More importantly, we found high correlations between younger and older adults, showing that our data are generalizable across different ages. However, despite this across-ages accord, we obtained age-related differences on three affective dimensions for a great number of words. In particular, older adults rated as more arousing and more unpleasant a number of words that younger adults rated as moderately unpleasant and arousing in our previous affective norms. Moreover, older participants rated negative stimuli as more arousing and positive stimuli as less arousing than younger participants, thus leading to a less-curved distribution of ratings in the valence by arousal space. We also found more extreme ratings for older adults for the relationship between dominance and arousal: older adults gave lower dominance and higher arousal ratings for words rated by younger adults with middle dominance and arousal values. Together, these results suggest that our affective norms are reliable and can be confidently used to select words matched for the affective dimensions of valence, arousal and dominance across younger and older participants for future research in aging.
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Effects of communication efficiency and exit capacity on fundamental diagrams for pedestrian motion in an obscure tunnel|a particle system approach
Fundamental diagrams describing the relation between pedestrians speed
and density are key points in understanding pedestrian dynamics.
Experimental data evidence the onset of complex behaviors in which the
velocity decreases with the density and different logistic regimes are
identified. This paper addresses the issue of pedestrians transport and of fundamental diagrams for a scenario involving the motion of pedestrians
escaping from an obscure tunnel.
% via a simple one--dimensional particle system model.
We capture the effects of the communication efficiency and
the exit capacity by means of two thresholds controlling the rate
at which particles (walkers, pedestrians) move on the lattice.
Using a particle system model, we show that in absence of limitation in communication among
pedestrians we reproduce
with good accuracy the standard fundamental diagrams, whose
basic behaviors can be interpreted in terms of the exit capacity
limitation.
When the effect of a limited communication ability is considered, then
interesting non--intuitive phenomena occur. Particularly, we shed light on
the loss of monotonicity of the typical speed--density curves,
revealing the existence of a
pedestrians density optimizing the escape.
We study both the discrete particle dynamics as well as the corresponding hydrodynamic limit (a porous medium equation and a transport (continuity) equation). We also point out the dependence of the effective transport coefficients on the two thresholds -- the essence of the microstructure information
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