Search results for "model [emission]"
showing 10 items of 625 documents
Imaging of VSOP labeled stem cells in agarose phantoms with susceptibility weighted and T2* weighted MR Imaging at 3T: determination of the detection…
2013
Objectives This study aimed to evaluate the detectability of stem cells labeled with very small iron oxide particles (VSOP) at 3T with susceptibility weighted (SWI) and T2* weighted imaging as a methodological basis for subsequent examinations in a large animal stroke model (sheep). Materials and Methods We examined ovine mesenchymal stem cells labeled with VSOP in agarose layer phantoms. The experiments were performed in 2 different groups, with quantities of 0–100,000 labeled cells per layer. 15 different SWI- and T2*-weighted sequences and 3 RF coils were used. All measurements were carried out on a clinical 3T MRI. Images of Group A were analyzed by four radiologists blinded for the num…
The model of governance of the professional football sector in Italy: a critical analysis
2012
The current model of governance of football in Italy has been formally followed by the clubs, but does not effectively address the manifestation of problems such as illegal betting or match fixing. By proposing a taxonomy of pathologies to which professional football is exposed, we highlight some gaps for the identification of tools and procedures useful for the reorientation of club management towards the satisfaction of sporting, economic, social and communicative dimensions.
Consistency of Independent Component Analysis for FMRI
2021
Background Independent component analysis (ICA) has been widely used for blind source separation in the field of medical imaging. However, despite of previous substantial efforts, the stability of ICA components remains a critical issue which has not been adequately addressed, despite numerous previous efforts. Most critical is the inconsistency of some of the extracted components when ICA is run with different model orders (MOs). New Method In this study, a novel method of determining the consistency of component analysis (CoCA) is proposed to evaluate the consistency of extracted components with different model orders. In the method, “consistent components” (CCs) are defined as those whic…
Tensor clustering on outer-product of coefficient and component matrices of independent component analysis for reliable functional magnetic resonance…
2019
Background. Stability of spatial components is frequently used as a post-hoc selection criteria for choosing the dimensionality of an independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data. Although the stability of the ICA temporal courses differs from that of spatial components, temporal stability has not been considered during dimensionality decisions. New method. The current study aims to (1) develop an algorithm to incorporate temporal course stability into dimensionality selection and (2) test the impact of temporal course on the stability of the ICA decomposition of fMRI data via tensor clustering. Resting state fMRI data were analyzed with two popu…
Ecologists overestimate the importance of predictor variables in model averaging: a plea for cautious interpretations.
2014
Abstract: Information-theory procedures are powerful tools for multimodel inference and are now standard methods in ecology. When performing model averaging on a given set of models, the importance of a predictor variable is commonly estimated by summing the weights of models where the variable appears, the so-called sum of weights (SW). However, SWs have received little methodological attention and are frequently misinterpreted. We assessed the reliability of SW by performing model selection and averaging on simulated data sets including variables strongly and weakly correlated to the response variable and a variable unrelated to the response. Our aim was to investigate how useful SWs are …
Model selection procedure for mixture hidden Markov models
2021
This paper proposes a model selection procedure to identify the number of clusters and hidden states in discrete Mixture Hidden Markov models (MHMMs). The model selection is based on a step-wise approach that uses, as score, information criteria and an entropy criterion. By means of a simulation study, we show that our procedure performs better than classical model selection methods in identifying the correct number of clusters and hidden states or an approximation of them
Clickstream Data Analysis: A Clustering Approach Based on Mixture Hidden Markov Models
2023
Nowadays, the availability of devices such as laptops and cell phones enables one to browse the web at any time and place. As a consequence, a company needs to have a website so as to maintain or increase customer loyalty and reach potential new customers. Besides, acting as a virtual point-of-sale, the company portal allows it to obtain insights on potential customers through clickstream data, web generated data that track users accesses and activities in websites. However, these data are not easy to handle as they are complex, unstructured and limited by lack of clear information about user intentions and goals. Clickstream data analysis is a suitable tool for managing the complexity of t…
Vammaisuuden sukupuolittuneet ja sortavat diskurssit : yhteiskunnallis-diskursiivinen näkökulma vammaisuuteen
2007
Väitöstyössään Marjo-Riitta Reinikainen tutkii kriittisellä otteella tavanomaista arkista puhetta vammaisuudesta. Huomion kohteena ovat vammaisuudelle ja vammaisena olemiselle teksteissä annetut merkitykset, erityisesti näiden sukupuolittuneet sekä vammaisten sortoa ja syrjintää tuottavat ja ylläpitävät muodot. Reinikaisen tutkimissa teksteissä vammainen mies kuvataan usein oletettujen positiivisten ominaisuuksiensa, kykyjensä ja saavutustensa kautta, kun taas vammainen nainen kuvataan pikemminkin menetystensä ja puutteidensa kautta. – Kun vammaispuhetta tarkastellaan sukupuolinäkökulmasta, käsitykset vammaisuudesta ja vammaisena olemisesta näyttäytyvät selvästi sukupuolittuneina. Tosin san…
Identifying the Neurocognitive bases of creativity to increase human and computational creativity
2022
En esta Tesis Doctoral se ha identificado la estructura neurocognitiva que sustenta la creatividad humana a partir del análisis conjunto de más de 800 referencias bibliográficas que muestran las investigaciones más importantes realizadas hasta la fecha. Sobre la base de esta estructura, se ha identificado un paradigma neurocognitivo de la creatividad humana y se ha propuesto un modelo neurocognitivo del proceso creativo. Finalmente, también se ha propuesto un paradigma creativo neurocognitivo computacional y se ha diseñado la estructura de un sistema computacional creativo, basado en una estructura multiagente. La investigación que se ha realizado sobre el tema hasta la fecha es muy especia…
Trans-Contextual Model Predicting Change in Out-of-School Physical Activity: A One-Year Longitudinal Study
2021
The aim of the current study was to test the long-term predictive validity of the trans-contextual model in accounting for variance in adolescents’ out-of-school physical activity measured by self-report and accelerometer based-devices over a one-year period. Secondary school students ( N = 265) aged 11 to 15 years completed a three-wave survey on two occasions in time, spanning a one-year interval, measuring perceived autonomy support in physical education (PE), peer and parent autonomy support in leisure-time, autonomous and controlled motivation in PE and leisure-time, attitude, subjective norms, perceived behavioural control, intention, and out-of-school physical activity both by sel…