Browsing by Subject "SEM"

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  • Poletaev, Dmitry (Helsingfors universitet, 2017)
    Goals. The goal of this research was to find out, how the use of the non-identifying dynamic algorithm would affect fairness experience; and through it, behavioral intentions, in rebating context. Besides that, it was assessed how the provision of detailed information on algorithm's logic affects the fairness experience. Dynamic pricing, especially based on identification, has been shown to negatively affect fairness. The dynamic algorithms are better to companies due to their profitability potential. It is of vital importance to find out the conditions, on which they might be employed, while taking into account the possible reactions of the customers. A differential assessment of entity and event fairness through the lens of fairness heuristic theory is chosen as a backbone of this research to extend the mosaic empirical evidence of their mutual interaction paths. The fairness experience is also closely connected to affects; incidental affects and integral emotions, which are evoked by the fairness experience itself. Because of this close relationship, to complement general picture, the affects were assessed as well. Methods. The manipulations were performed on two levels. The first level, the exposure to dynamic algorithm or seeing the human-set pre-determined rebate rates, happened on the company's site when the algorithm trial was run. The second manipulation level, the amount of the available information, was performed during the gathering of the survey data. There were three conditions in the information manipulation: no information (the control), bare information about the ongoing trial and trial information including a detailed algorithm's logic description. The size of the final sample, used for the analysis, consisted of 404 participants. The main analysing technique employed was SEM. Results and conclusions. Effect paths between entity and event fairness areas were in accordance with the fairness heuristic theory - event fairness mediated the change in entity fairness partially. The subjects that were exposed to the algorithm, event fairness was affected negatively by the bare trial information as expected. The provision of the detailed information did not affect fairness. Entity fairness was connected to both, incidental affects and integral emotions. There were no analogous connection between event fairness, and affects and emotions. Fairness mediated only partially the change from incidental affects to integral emotions. Integral emotions were not connected to the behavioral intentions. Entity fairness mediated fully the effect of event fairness on the behavioral intentions. The provision of the detailed information affected directly positively on pro-active behavioral intentions without a mediation of fairness. None of the manipulations affected directly complaining intentions. The results provide important information about the dynamic algorithm exposure in real life, outside the laboratories. Despite the dynamic pricing being seen as unfair in principle, the exposure to the detailed information might have positive effects on the outcomes. There was only a limited support for the role of affects in the pricing fairness context.
  • Ritola, Ville (Helsingfors universitet, 2016)
    Background. Knowing what a psychological test measures and if it works the same way in different contexts, i.e. has measurement invariance (MI), is crucial for its valid and reliable use. The Wechsler Adult Intelligence Scale – Fourth Edition (WAIS-IV) was published in Finland in 2012. However, recent research suggests that the factor model given in the WAIS-IV test manual and the information regarding MI between different age groups and levels of education are lacking. Methods. This study employed the normative sample of the Finnish WAIS-IV. First, the factor model in the manual was examined and improved using confirmatory factor analysis with a mixed data-theory approach. Second, the new model was tested for strict residual MI for different age groups and levels of education, in order to study if the test reaches an acceptable level of MI. Results and conclusions. The results indicated that the normative data is best modeled by an oblique non-g model. The study also replicated a Spatial Visualization factor with loadings from Block Design, Visual Puzzles and Picture Completion, and Quantitative Reasoning factor with Figure Weights and Arithmetic. A previously unmentioned link in factor analytic literature on WAIS-IV was found between Block Design and Processing Speed factors. The results questioned the link between Arithmetic and Verbal Comprehension factor and found the underlying source of shared variance to be links between Information and Arithmetic, which was interpreted as Educational Achievement. WAIS-IV reached strict residual MI for both different age groups and levels of education. The study offers a more accurate factor model of WAIS-IV and gives confidence that psychologists can reliably apply it over different ages and levels of education in the normal population of Finland.
  • Friedmann, Andrea; Goehre, Felix; Ludtka, Christopher; Mendel, Thomas; Meisel, Hans-Joerg; Heilmann, Andreas; Schwan, Stefan (2017)
    Degeneration of intervertebral disc (IVD) tissue is characterized by several structural changes that result in variations in disc physiology and loss of biomechanical function. The complex process of degeneration exhibits highly intercorrelated biomechanical, biochemical, and cellular interactions. There is currently some understanding of the cellular changes in degenerated intervertebral disc tissue, but microstructural changes and deterioration of the tissue matrix has previously been rarely explored. In this work, sequestered IVD tissue was successfully characterized using histology, light microscopy, and scanning electron microscopy (SEM) to quantitatively evaluate parameters of interest for intervertebral disc degeneration (IDD) such as delamination of the collagenous matrix, cell density, cell size, and extra cellular matrix (ECM) thickness. Additional qualitative parameters investigated included matrix fibration and irregularity, neovascularization of the IVD, granular inclusions in the matrix, and cell cluster formation. The results of this study corroborated several previously published findings, including those positively correlating female gender and IVD cell density, age and cell size, and female gender and ECM thickness. Additionally, an array of quantitative and qualitative investigations of IVD degeneration could be successfully evaluated using the given methodology, resin-embedded SEM in particular. SEM is especially practical for studying micromorphological changes in tissue, as other microscopy methods can cause artificial tissue damage due to the preparation method. Investigation of the microstructural changes occurring in degenerated tissue provides a greater understanding of the complex process of disc degeneration as a whole. Developing a more complete picture of the degenerative changes taking place in the intervertebral disc is crucial for the advancement and application of regenerative therapies based on the pathology of intervertebral disc degeneration. (C) 2016 Elsevier Ltd. All rights reserved.