Wavelet analysis on the circle

International audienceThe construction of a wavelet analysis over the circle is presented. The spaces of infinitely times differentiable functions, tempered distributions, and square integrable functions over the circle are analyzed by means of the wavelet transform

Overconfidence & career development - evidence from an online experiment

This paper studies the influence of work-experience and professionalism on general overconfidence. An online experiment has been conducted to compare the level of overconfidence between 5 different subject groups of a total sample of 270 individuals from 35 different countries. Socioeconomic control variables have been used to better clarify the unique influence of experience on the overconfidence level. The findings of this quantitative study suggest that even high levels of work experience do not significantly reduce overconfidence. This generates some major implications and tasks for businesses and organizations to be able to reduce the most damaging of existing heuristics

Loading rates in California inferred from aftershocks

International audienceWe estimate the loading rate in southern California and the change in stress induced by a transient slip event across the San Andreas fault (SAF) system in central California, using a model of static fatigue. We analyze temporal properties of aftershocks in order to determine the time delay before the onset of the power law aftershock decay rate. In creep-slip and stick-slip zones, we show that the rate of change of this delay is related to seismic and aseismic deformation across the SAF system. Furthermore, we show that this rate of change is proportional to the deficit of slip rate along the SAF. This new relationship between geodetic and seismological data is in good agreement with predictions from a Limited Power Law model in which the evolution of the duration of a linear aftershock decay rate over short time results from variations in the load of the brittle upper crust

Alterations in prefrontal-limbic functional activation and connectivity in chronic stress-induced visceral hyperalgesia.

Repeated water avoidance stress (WAS) induces sustained visceral hyperalgesia (VH) in rats measured as enhanced visceromotor response to colorectal distension (CRD). This model incorporates two characteristic features of human irritable bowel syndrome (IBS), VH and a prominent role of stress in the onset and exacerbation of IBS symptoms. Little is known regarding central mechanisms underlying the stress-induced VH. Here, we applied an autoradiographic perfusion method to map regional and network-level neural correlates of VH. Adult male rats were exposed to WAS or sham treatment for 1 hour/day for 10 days. The visceromotor response was measured before and after the treatment. Cerebral blood flow (CBF) mapping was performed by intravenous injection of radiotracer ([(14)C]-iodoantipyrine) while the rat was receiving a 60-mmHg CRD or no distension. Regional CBF-related tissue radioactivity was quantified in autoradiographic images of brain slices and analyzed in 3-dimensionally reconstructed brains with statistical parametric mapping. Compared to sham rats, stressed rats showed VH in association with greater CRD-evoked activation in the insular cortex, amygdala, and hypothalamus, but reduced activation in the prelimbic area (PrL) of prefrontal cortex. We constrained results of seed correlation analysis by known structural connectivity of the PrL to generate structurally linked functional connectivity (SLFC) of the PrL. Dramatic differences in the SLFC of PrL were noted between stressed and sham rats under distension. In particular, sham rats showed negative correlation between the PrL and amygdala, which was absent in stressed rats. The altered pattern of functional brain activation is in general agreement with that observed in IBS patients in human brain imaging studies, providing further support for the face and construct validity of the WAS model for IBS. The absence of prefrontal cortex-amygdala anticorrelation in stressed rats is consistent with the notion that impaired corticolimbic modulation acts as a central mechanism underlying stress-induced VH

Wavelets on Discrete Fields

International audienceAn arithmetic version of continuous wavelet analysis is described. Starting from a square-integrable representation of the affine group of Z Z p (or Z Z) it is shown how wavelet decom-positions of ℓ 2 (Z Z p) can be obtained. Moreover, a redefinition of the dilation operator on ℓ 2 (Z Z p) directly yields an algorithmic structure similar to that appearing with multiresolution analyses