197,519 research outputs found
Aplicação de técnicas de controle robusto baseadas em LMI'S para sistemas elétricos de potência /
No full textDissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico.Este trabalho apresenta um método de projeto robusto decontroladores de Sistemas de Potência via Inequações Matriciais Lineares (LMI's), de modo a fornecer maior amortecimento para as oscilações eletromecânicas do sistema. Com o projeto robusto do controlador, a estabilidade do sistema deve ser assegurada na presença de incertezas no mesmo, onde estas incertezas foram consideradas neste trabalho como sendo do tipo Linear Convexa. Duas abordagens utilizandoLMI's foram consideradas, sendo a primeira um problema de factibilidade e a segunda um problema de dedesempenho H2. Em ambas as abordagens resolve-se um problema convexo de otimização. O sistema é representado na forma algébrico-diferencial. O controlador utiliza a estrutura comumente empregada na indústria com realimentação desaídas. A viabilidade destas abordagens bem como suas limitações foram avaliadas através de testes em um sistema máquina x barra infinita e um sistema multimáquinas. Simulações dos sistemas não-lineares foram utilizadas para comprovar os resultados
INHERITED HEARING LOSS: FROM GENE VARIANTS TO MECHANISMS OF DISEASE
No full textNonsyndromic Sensorineural Hearing Loss (NSHL) is the most common sensory disorder worldwide, affecting at least 1 in 500 newborns and more than half individuals older than 80 years. It is estimated that about 60-70% of cases are due to genetic factors [Raviv et al., 2010]. More than 70 genes have been associated with NSHL so far, but many others are still to be discovered. In this thesis, we investigated the genetic and molecular bases of NSHL by a double approach, consisting in: a) investigating the pathogenic mechanisms of mutations within the MIR96 gene, and b) searching for new genes/mutations by Whole-Exome Sequencing (WES) in selected NSHL families.
As far as MIR96 is concerned, we identified and characterized a novel mutation (the third described) within the MIR96 gene, miR-96 (+57T>C), in an Italian family with autosomal dominant NSHL. MiR-96 is part of the conserved miR-183 microRNA (miRNA) family, which plays essential functions in the vertebrate inner ear. Point mutations within the seed region of miR-96 (miR-96-5p) cause autosomal dominant NSHL (AD-NSHL). The novel identified mutation replaces a highly conserved nucleotide and is predicted to reduce the stability of the pre-miRNA hairpin. Ex vivo assays in mammalian cells confirmed that both miR-96 and miR-96*(miR-96-3p) mature species were significantly reduced in the mutant, whereas the precursor level was unaffected. Moreover, miR-96 and miR-96* expression could be restored to normal levels by reconstituting the secondary structure of the pre-miR-96 hairpin, thus demonstrating that the mutation hinders the precursor processing. Finally, even though the mature miR-96 sequence is not altered, we demonstrated that the identified mutation significantly impacts on miR-96 regulation of selected targets. Taken together, these data provide further evidence of the involvement of miR-96 in human deafness and demonstrate that a quantitative defect of this miRNA may contribute to NSHL.
As far as WES is concerned, the application of NGS to the identification of novel genes/mutations in 6 genetically undiagnosed Italian families (NSHL1-4 and 6, 7), with recessive NSHL and at least two affected individuals, has enabled the molecular diagnosis in two families (NSHL4 and NSHL6), and highlighted a putative novel deafness-associated gene in another family (NSHL3). In particular, a novel missense mutation within the PRPS1 gene was found in family NSHL4 and functionally characterized, together with other two mutations identified by candidate-gene screening in a larger X-linked NSHL cohort. In the NSHL3 family, WES pointed out a novel missense variant in DIAPH2, a gene not directly linked to NSHL but belonging to a family of proteins already involved in hearing loss. Studies aimed at the functional characterization of this mutation and at the clarification of the possible involvement of the gene in the pathogenesis of the disease are now being performed.
For the other three families (NSHL1, 2 and NSHL7), the search for pathogenic variations is still ongoing
A guided tutorial on linear mixed-effects models for the analysis of accuracies and response times in experiments with fully crossed design
No full textExperiments with fully crossed designs are often used in experimental psychology spanning several fields, from cognitive psychology to social cognition. These experiments consist in the presentation of stimuli representing super-ordinate categories, which have to be sorted into the correct category in two contrasting conditions. This tutorial presents a linear mixed-effects model approach for obtaining Rasch-like parameterizations of response times and accuracies of fully crossed design data. The modeling framework for the analysis of fully crossed design data is outlined along with a step-by-step guide of its application, which is further illustrated with two practical examples based on empirical data. The first example regards a cognitive psychology experiment
and pertains to the evaluation of a spatial–numerical association of response codes effect. The second one is based on a social cognition experiment for the implicit evaluation of racial attitudes.A fully commentedR script for reproducing the analyses illustrated in the examples is available in the online supplemental materials
Is the performance at the implicit association test sensitive to feedback presentation? A Rasch-based analysis
No full textThe Implicit Association Test (IAT) is commonly used for the indirect assessment of psychological constructs. While the features of the IAT that might influence the performance of the respondents have been extensively investigated, the effect of informing the respondents about the correctness of their responses (i.e., feedback presentation) has been poorly addressed so far. The study addresses this issue by presenting an across-domain (implicit prejudice and food preference) Rasch-based analysis of IAT data obtained with and without feedback presentation. Results showed that speed was influenced by the interaction between feedback presentation and associative condition, whereas accuracy was influenced by the associative condition. This result varied across-domain. Results suggested that IATs administered with feedback presentation provide more accurate information on the construct of interest
DscoreApp: A Shiny Web Application for the Computation of the Implicit Association Test D-Score
No full textSeveral options are available for computing the most common score for the Implicit Association Test, the so-called D-score. However, all these options come with some drawbacks, related to either the need for a license, for being tailored on a specific administration procedure, or for requiring a degree of familiarity with programming. By using the R shiny package, a user-friendly, interactive, and open source web application (DscoreApp) has been created for the D-score computation. This app provides different options for computing the D-score algorithms and for applying different cleaning criteria. Beyond making the D-score computation easier, DscoreApp offers the chance to have an immediate glimpse on the results and to see how they change according to different settings configurations. The resulting D-scores are immediately available and can be seen in easy-readable and interactive graphs, along with meaningful descriptive statistics. Graphical representations, data sets containing the D-scores, and other information on participants' performance are downloadable. In this work, the use of DscoreApp is illustrated on an empirical data set
Development of two scales for measuring academic psychological capital and locus of control in fresh graduates
No full textThis work develops within PETERE, a project of the University of Padova that investigated how fresh graduates interact with the labour market in order to improve placement plans. A set of psychological characteristics have been identified as crucial resources for the occupational success: the positive psychological capital (PsyCap) dimensions (hope, resilience, self-efficacy, and optimism) and locus of control (LoC) dimensions (internal and external). Two instruments have been developed for the evaluation of these individual dispositions among fresh graduates: the Academic PsyCap and the LoC scales. In the final form, the two tools consist of 26 and 7 items respectively, which have been selected, through factor analyses, from an initial pool of items specifically developed for fresh graduates. Results suggested adequate psychometric properties for both the Academic PsyCap and the LoC scales. The factor structure of the two instruments was confirmed, and reliability indices were satisfactory for all the subscales of the tools. The Academic PsyCap and the LoC scales, in addition, showed significant relationships with the occupational status of respondents, with their entrepreneurial disposition, and with the number of actions taken when they are looking for a job
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