615 research outputs found
Fractal analysis of weld defect patterns obtained by radiographic tests
This paper presents a fractal analysis of radiographic patterns obtained from
specimens with three types of inserted welding defects: lack of fusion, lack of
penetration, and porosity. The study focused on patterns of carbon steel beads
from radiographs of the International Institute of Welding (IIW). The
radiographs were scanned using a greyscale with 256 levels, and the fractal
features of the surfaces constructed from the radiographic images were
characterized by means of Hurst, detrended-fluctuation, and minimal-cover
analyses. A Karhunen-Loeve transformation was then used to classify the curves
obtained from the fractal analyses of the various images, and a study of the
classification errors was performed. The obtained results indicate that fractal
analyses can be an effective additional tool for pattern recognition of weld
defects in radiographic tests.Comment: 7 pages, 2 figures. To appear AIP Conference Proceedings - QNDE 200
Evolution of populations expanding on curved surfaces
The expansion of a population into new habitat is a transient process that
leaves its footprints in the genetic composition of the expanding population.
How the structure of the environment shapes the population front and the
evolutionary dynamics during such a range expansion is little understood. Here,
we investigate the evolutionary dynamics of populations consisting of many
selectively neutral genotypes expanding on curved surfaces. Using a combination
of individual-based off-lattice simulations, geometrical arguments, and
lattice-based stepping-stone simulations, we characterise the effect of
individual bumps on an otherwise flat surface. Compared to the case of a range
expansion on a flat surface, we observe a transient relative increase, followed
by a decrease, in neutral genetic diversity at the population front. In
addition, we find that individuals at the sides of the bump have a dramatically
increased expected number of descendants, while their neighbours closer to the
bump's centre are far less lucky. Both observations can be explained using an
analytical description of straight paths (geodesics) on the curved surface.
Complementing previous studies of heterogeneous flat environments, the findings
here build our understanding of how complex environments shape the evolutionary
dynamics of expanding populations.Comment: This preprint has also been posted to http://www.biorxiv.org with
doi: 10.1101/406280. Seven pages with 5 figures, plus an appendix containing
3 pages with 1 figur
Conflicted Emotions Following Trust-based Interaction
We investigated whether 20 emotional states, reported by 170 participants after participating in a Trust game, were experienced in a patterned way predicted by the “Recalibrational Model” or Valence Models. According to the Recalibrational Model, new information about trust-based interaction outcomes triggers specific sets of emotions. Unlike Valence Models that predict reports of large sets of either positive or negative emotional states, the Recalibrational Model predicts the possibility of conflicted (concurrent positive and negative) emotional states. Consistent with the Recalibrational Model, we observed reports of conflicted emotional states activated after interactions where trust was demonstrated but trustworthiness was not. We discuss the implications of having conflicted goals and conflicted emotional states for both scientific and well-being pursuits
Does Culture Explain? Understanding Differences in School Attainment between Iberian and Turkish Youth in the Netherlands
Prevenção quaternária na atenção primária à saúde: uma necessidade do Sistema Único de Saúde
Emotional gratification in entertainment experience
This article presents four studies designed to assess different types of gratifications that can be associated with the experience of emotions in movie and television audiences. Exploratory and confirmatory factor analyses of a pool of statements derived from qualitative interviews revealed three factors that reflect rewarding feelings: 1) fun, 2) thrill, and 3) empathic sadness, and four factors that reflect the role of emotional media experiences within the broader context of individuals' social and cognitive needs: 4) contemplative emotional experiences, 5) emotional engagement with characters, 6) social sharing of emotions, and 7) vicarious release of emotions. Validation analyses showed that the scales developed to assess these factors are predicted by the experience of emotions and meta-emotions and served in turn to predict different aspects of positive content evaluation. Results are discussed with regard to theoretical issues including entertainment audiences' voluntary exposure to unpleasant feelings, and the role of entertainment in psychosocial need satisfaction and eudaimonic wellbeing
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