50 research outputs found

    Are entrepreneurs' forecasts of economic indicators biased?

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    Insight into the investment behaviour of firms is central in understanding economic dynamics. A critical question, however, is whether firms provide sufficiently reliable data to enable them to make plausible forecasts at the meso (regional or sectoral) level. This paper analyses Dutch investment forecasts at different levels of aggregation. The central research question is whether entrepreneurs, individually or as a group, make systematic errors in their investment forecasts. A statistical test reveals that investment forecasts are not biased at the aggregated (regional and sectoral) level. At the micro level, however, there is a significant bias. Hence, using aggregated (regional and sectoral) data to test the lack of bias (unbiasedness) of forecasts may lead to the wrong conclusions. Moreover, aggregated investment forecasts may then be an inappropriate source for policy recommendations, despite their seemingly high reliability. This finding may in principle be valid for many European countries, since data collection on investment is organized in similar ways throughout Europe

    Markers of serotonergic function in the orbitofrontal cortex and dorsal raphé nucleus predict individual variation in spatial-discrimination serial reversal learning.

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    Dysfunction of the orbitofrontal cortex (OFC) impairs the ability of individuals to flexibly adapt behavior to changing stimulus-reward (S-R) contingencies. Impaired flexibility also results from interventions that alter serotonin (5-HT) and dopamine (DA) transmission in the OFC and dorsomedial striatum (DMS). However, it is unclear whether similar mechanisms underpin naturally occurring variations in behavioral flexibility. In the present study, we used a spatial-discrimination serial reversal procedure to investigate interindividual variability in behavioral flexibility in rats. We show that flexibility on this task is improved following systemic administration of the 5-HT reuptake inhibitor citalopram and by low doses of the DA reuptake inhibitor GBR12909. Rats in the upper quintile of the distribution of perseverative responses during repeated S-R reversals showed significantly reduced levels of the 5-HT metabolite, 5-hydroxy-indoleacetic acid, in the OFC. Additionally, 5-HT2A receptor binding in the OFC of mid- and high-quintile rats was significantly reduced compared with rats in the low-quintile group. These perturbations were accompanied by an increase in the expression of monoamine oxidase-A (MAO-A) and MAO-B in the lateral OFC and by a decrease in the expression of MAO-A, MAO-B, and tryptophan hydroxylase in the dorsal raphé nucleus of highly perseverative rats. We found no evidence of significant differences in markers of DA and 5-HT function in the DMS or MAO expression in the ventral tegmental area of low- vs high-perseverative rats. These findings indicate that diminished serotonergic tone in the OFC may be an endophenotype that predisposes to behavioral inflexibility and other forms of compulsive behavior.This work was supported by Medical Research Council Grants (G0701500; G0802729), a 503 Wellcome Trust Programme Grant (grant number 089589/Z/09/Z), and by a Core Award 504 from the Medical Research Council and the Wellcome Trust to the Behavioural and Clinical 505 21 Neuroscience Institute (MRC Ref G1000183; WT Ref 093875/Z/10/Z). RLB was supported 506 by a studentship from the Medical Research Council. JA was supported by a Fellowship from 507 the Swedish Research Council (350-2012-230). BJ was supported by Fellowships from the 508 AXA Research Fund and the National Health and Medical Research Council of Australia. 509 Financial support from the Fredrik and Ingrid Thuring Foundation is also acknowledged.This is the accepted manuscript. The final version is available from Nature Publishing at http://www.nature.com/npp/journal/vaop/ncurrent/full/npp2014335a.html

    Measurement of the ratio of the ppˉWp\bar{p}\to W+cc-jet cross section to the inclusive ppˉWp\bar{p}\to W+jets cross section

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    We present a measurement of the fraction of inclusive WW+jets events produced with net charm quantum number ±1\pm1, denoted WW+cc-jet, in ppˉp\bar{p} collisions at s=1.96\sqrt{s}=1.96 TeV using approximately 1~fb1^{-1} of data collected by the D0 detector at the Fermilab Tevatron Collider. We identify the WW+jets events via the leptonic WW boson decays. Candidate WW+cc-jet events are selected by requiring a jet containing a muon in association with a reconstructed WW boson and exploiting the charge correlation between this muon and WW boson decay lepton to perform a nearly model-independent background subtraction. We measure the fraction of WW+cc-jet events in the inclusive WW+jets sample for jet pT>20p_{T}>20 GeV and pseudorapidity η<2.5|\eta|<2.5 to be 0.074±0.019\pm0.019(stat.)±0.0140.012\pm^{0.012}_{0.014}(syst.), in agreement with theoretical predictions. The probability that background fluctuations could produce the observed fraction of WW+cc-jet events is estimated to be 2.5×1042.5\times 10^{-4}, which corresponds to a 3.5 σ\sigma statistical significance.Comment: submitted to Physics Letters
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