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BACKGROUND: For quantitative and qualitative evaluation of the imaging properties of IOLs, axial cross-sectional images can be obtained from the 3-dimensional light distribution by means of an optical bench, as is known from light sheet recordings in fluorescein baths. This paper presents a new image-processing algorithm to enhance the quality of generated axial cross-sectional images, and the two methods are then compared. MATERIAL AND METHODS: The 3-dimensional point spread function of a diffractive trifocal IOL (AT LISA tri 839MP, Carl Zeiss Meditec AG, Jena, Germany) was recorded on an optical bench developed in Rostock for different pupil diameters. A specially adapted image processing algorithm was then applied to the measurements, allowing through-focus curves to be generated. In addition, cross-sectional images of the IOLs studied were acquired using the light sheet method in a fluorescein bath. RESULTS: The study clearly shows the superiority of the newly developed method over the light sheet method in terms of image quality. In addition to the individual focal points, fine focal structures as well as halos can be made visible in the cross-sectional images obtained using the new method. In the generated through-focus curves, 3 intensity peaks can be identified, which represent the near, intermediate and far focus of the tested MIOL and cannot be represented by light sheet methods. CONCLUSION: The interaction of the optical bench with the developed image processing algorithm allows a more detailed understanding of the image formation and false light phenomena of IOLs, which was restricted by the technical limitations of the existing light sheet method. In addition, other quantities such as the through-focus curve can be derived quantitatively.
Assuntos
Lentes Intraoculares , Humanos , Fluoresceína , Desenho de Prótese , Visão Ocular , Processamento de Imagem Assistida por Computador , Refração OcularRESUMO
First-generation students (FGS) are more likely to feel misplaced and struggle at university than students with university-educated parents (continuous-generation students; CGS). We assumed that the shutdowns during the Coronavirus-pandemic would particularly threaten FGS due to obstructed coping mechanisms. Specifically, FGS may show lower identification with the academic setting and lower perceived fairness of the university system (system justification). We investigated whether FGS and CGS used different defenses to cope with the shutdown threat in a large sample of German-speaking students (N = 848). Using Structural Equation Modeling, we found that for all students, independent of academic parental background, high levels of system justification were associated with perceiving the learning situation as less threatening, better coping with failure, and less helplessness. However, in comparison to CGS, FGS showed small but significant reductions in system justification and relied more on concrete personal relationships with other students as well as their academic identity to cope with the threatening situation. We discuss implications for helping FGS succeed at university.
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Over the recent years, research in the field of threat and defense has accumulated evidence on how encounters with various psychological threats influence human behavior, cognition, motivation, affect, and health. Unifying different theoretical threat models, the General Process Model of Threat and Defense claims that different threatening concerns have a similar underlying dynamic. Some years after the publication of this theory, we deem it important to take a comparative look at psychological threat, comparing threats regarding their properties and outcomes on personal and social level. As potential dimensions to describe psychological threats, we discuss the existential nature of concerns, phenomenological worlds involved, and thwarted needs in threat encounters. We also discuss data-driven approaches to threat classifications, describing first empirical efforts to create threat taxonomies, and suggest directions for future research. This research will enhance our understanding of threat dynamics, and will help us make stronger, more clear-cut assumptions about human behavior upon experiencing threat.
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The COVID-19 pandemic has interrupted everyday life virtually everywhere in the world, enabling real-life research on threat-and-defense processes. In a survey conducted within the first days of implementing social distancing measures in Austria and Germany, we aimed to explore the pathways from threat perception to preferences of defense strategies. We found that anxiety, approach-related affect, and reactance were specifically elicited by motivational (vs. epistemic) discrepancies. In a second step, we tested the mediating effect of anxiety, approach-related affect, and reactance on preferences regarding personal-social and concrete-abstract defenses. Experiencing anxiety was related to interest in security-related actions, and approach-affect was related to both personal projects and social media use. Participants experiencing reactance were more inclined to pursue personal projects (personal-abstract) and less interested in security-related (personal-concrete) actions. They also showed marginally lower system justification (social-abstract). Additionally, we examined the relationship of loneliness with defense strategies, showing that loneliness was associated with lower system justification and security behaviors. The results suggest that individuals deal with threat in their own ways, mostly depending on affective state and motivational orientation: Anxiety was related to security, approach-state to action (both social and personal), reactance to derogation of the system and disregard for security, while loneliness was associated with inaction.
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Ansiedade/psicologia , COVID-19/psicologia , Isolamento Social/psicologia , Adolescente , Adulto , Idoso , Transtornos de Ansiedade/psicologia , Áustria/epidemiologia , Mecanismos de Defesa , Emoções/fisiologia , Feminino , Alemanha/epidemiologia , Humanos , Solidão/psicologia , Masculino , Pessoa de Meia-Idade , Motivação , Pandemias , SARS-CoV-2/patogenicidade , Inquéritos e QuestionáriosRESUMO
People with strong (vs. moderate) political attitudes have been shown to exhibit less phasic reactivity to perceptual anomalies, presumably to prevent their committed meaning systems from being challenged by novel experiences. Several researchers have proposed that (but not tested whether) firmly committed individuals also engage in more attentional suppression of anomalies, likely mediated by prestimulus alpha power. We expected participants with strong (vs. moderate) political attitudes to display increased pre-stimulus alpha power when processing perceptual anomalies. We recorded electrophysiological activity during the presentation of normal cards (control group) or both normal and anomalous playing cards (experimental group; total N = 191). In line with our predictions, the presence of anomalous playing cards in the stimulus set increased prestimulus alpha power only among individuals with strong but not moderate political attitudes. As potential markers of phasic reactivity, we also analyzed the late positive potential (LPP) and earlier components of the event-related potential, namely P1, N1, and P300. The moderating effect of extreme attitudes on ERP amplitudes remained inconclusive. Altogether, our findings support the idea that ideological conviction is related to increased tonic responses to perceptual anomalies.