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showing 10 items of 7541 documents
The influence of nimodipine on chromatolysis of motoneurons following axotomy with and without reinnervation: A quantitative image analysis
1996
Using a recently developed image analysis method to quantify the time course of chromatolysis in injured motorneurons we tested the effect of the calcium entry blocker nimodipine (1000 ppm in food pellets) on regenerating and degenerating motoneurons. Following facial-facial, hypoglossal-hypoglossal anastomosis with complete regeneration and following facial and hypoglossal nerve resection which causes a partial neuronal degeneration and postoperative survival times of 4 to 112 days, the texture of the Nissl substance of facial and hypoglossal motoneurons was analyzed on both sides of the brainstem in paraffin serial sections with a VIDASplus image analyzer. Monitoring alterations of the Ni…
A Bayesian Learning Automata-Based Distributed Channel Selection Scheme for Cognitive Radio Networks
2014
We consider a scenario where multiple Secondary Users SUs operate within a Cognitive Radio Network CRN which involves a set of channels, where each channel is associated with a Primary User PU. We investigate two channel access strategies for SU transmissions. In the first strategy, the SUs will send a packet directly without operating Carrier Sensing Medium Access/Collision Avoidance CSMA/CA whenever a PU is absent in the selected channel. In the second strategy, the SUs implement CSMA/CA to further reduce the probability of collisions among co-channel SUs. For each strategy, the channel selection problem is formulated and demonstrated to be a so-called "Potential" game, and a Bayesian Lea…
Towards interpretable classifiers with blind signal separation
2012
Blind signal separation (BSS) is a powerful tool to open-up complex signals into component sources that are often interpretable. However, BSS methods are generally unsupervised, therefore the assignment of class membership from the elements of the mixing matrix may be sub-optimal. This paper proposes a three-stage approach using Fisher information metric to define a natural metric for the data, from which a Euclidean approximation can then be used to drive BSS. Results with synthetic data models of real-world high-dimensional data show that the classification accuracy of the method is good for challenging problems, while retaining interpretability.
An algorithm for earthquakes clustering based on maximum likelihood
2007
In this paper we propose a clustering technique set up to separate and find out the two main components of seismicity: the background seismicity and the triggered one. We suppose that a seismic catalogue is the realization of a non homogeneous space-time Poisson clustered process, with a different parametrization for the intensity function of the Poisson-type component and of the clustered (triggered) component. The method here proposed assigns each earthquake to the cluster of earthquakes, or to the set of independent events, according to the increment to the likelihood function, computed using the conditional intensity function estimated by maximum likelihood methods and iteratively chang…
Hospitalization for self-harm during the early months of the COVID-19 pandemic in France: A nationwide retrospective observational cohort study
2021
ABSTRACT Background Little is known to date about the impact of COVID-19 pandemic on self-harm. Methods The number of hospitalizations for self-harm (ICD-10 codes X60-X84) in France from 1st January to 31st August 2020 (including a two-month confinement) was compared to the same periods in 2017–2019. Statistical methods comprised Poisson regression, Cox regression and Student's t-test, plus Spearman's correlation test relating to spatial analysis of hospitalizations. Outcomes There were 53,583 self-harm hospitalizations in France during January to August 2020. Compared to the same period in 2019, this represents an overall 8·5% decrease (Relative Risk [95% Confidence Interval] = 0·91 [0·90–…
Enhanced detection of contrast regions in echocardiograms by adaptive quantization
2002
The statistics of ultrasound echo images are governed by Rayleigh statistics. The authors derive some experimentally verifiable predictions of this theory, compare them with experimental results obtained from echocardiographic images, and derive a new color coding scheme, (adaptive quantization) that is adapted to the signal-dependent noise predicted by theory. This results in some technical advantages and in an improved discrimination of regions of the echo image that are enhanced by echo contrast material. >
The design of sum-of-cisoids rayleigh fading channel simulators assuming non-isotropic scattering conditions
2010
In this letter, we introduce the Riemann sum method (RSM) as an effective tool for the design of sum-of-cisoids (SOC) simulators for narrowband mobile Rayleigh fading channels under non-isotropic scattering conditions. We compare the performance of the RSM with that of the generalized method of equal areas (GMEA) and the Lp-norm method (LPNM), which were until now the only methods available for the design of SOC simulators for non-isotropic scattering channels. The obtained results indicate that the RSM is better suited than the GMEA and the LPNM to emulate the channel's autocorrelation function (ACF), whereas the latter two methods are more precise regarding the approximation of the envelo…
Signaling through the 2008 Beijing Olympics—Using Mega Sport Events to Change the Perception and Image of the Host
2011
Abstract This paper provides an analysis on internet news reports about the Beijing Olympics 2008 and how China signaled throughout the event to external target groups. The analysis shows how the geographical areas China, USA, Europe and the “Rest of the World” perceived the Games. The results were interpreted regarding the principal agent theories' signaling to reduce information asymmetry for business and tourism and costly signaling to generate symbolic capital. Seven hundred and forty news reports were collected between 1 July and 30 September 2008, using Google Alerts with the keywords “Olympic Games Beijing 2008”. The reports were analysed with a quantitative content analysis using a …
Large-eddy simulations of turbulent flow with heat transfer in simple and complex geometries using Harwell-FLOW3D
1996
Abstract Large-eddy simulation (LES) results are presented and discussed for the turbulent flow with heat transfer in different geometrical configurations, including a plane channel, a channel bearing transverse square ribs on one of the walls, and a crossed-corrugated air heater. They were obtained using the computational fluid dynamics (CFD) code Harwell-FLOW3D (Release 2), finite-volume grids having up to 423 nodes, and the Smagorinsky subgrid model with several variants regarding near-wall damping and wall boundary conditions. The first problem (plane turbulent Poiseuille flow with heat transfer) was mainly used as a benchmark to investigate the influence of numerical methods (pressure-…
The character and origin of the manuscripts in the present edition
1995
In the following I try to provide the reader with all the details needed to insert the Godel essays appearing here in the broader context of the rest of his unpublished work, as well as everything about my personal work on them. I start with a short description of what can be found in the Godel Nachlass in Princeton, USA, by referring to the catalogue prepared by John Dawson. Then I attempt to justify the particular selection I made of the manuscripts which I finally decided to study, reconstruct and publish. Such an explanation seems to be advisable given the great amount of Godel’s material unpublished but still extant. Also, I describe some of the historical details relevant to understan…