A Numerical Study on Elliptical Instabilities in a Counter-Rotating Asymmetric Vortex Pair

The elliptical instability in two unequal counter rotating vortices is studied with numerical simulations for a circulation Reynolds number of ReΓ =3100. The initially Gaussian vortices with equal and opposite circulation but unequal peak vorticity and core size are subjected to random perturbations, and their time evolution in the linear phases is examined.Asymmetry is achieved by simultaneously increasing core radius and lowering peak vorticity on one vortex while keeping the properties on the other vortex fixed between simulations. The effects of this asymmetry on the interaction between the two vortices are then studied, and it is found that deformation is more prominent on the larger vortex with lower peak vorticity for all simulations due to the higher relative strain it experiences. The most unstable non-dimensional wavenumber increases for increasingly asymmetrical cases; the global growth rate of the most unstable mode is higher in the weakly asymmetrical pair than the symmetrical pair and the strongly asymmetrical pair

Loneliness Among Senior Citizens of Rural Kansas

The purpose of the researcher was to investigate loneliness in senior citizens in a very small rural town. The independent variables were age, gender, marital status, income, living situation, and the irrational beliefs of dependency, anxious over-concern, frustration reactivity, high self-expectations, problem avoidance, and helplessness. The dependent variable was scores from the UCLA Loneliness Scale (Version 3). Subjects were 129 retirees over the age of 60 living in a small rural town located in the center of the state of Kansas. A status survey factorial design with pre-grouping and post hoc grouping was employed. Eleven composite null hypotheses were tested. A total of 43 comparisons plus 34 recurring comparisons were made. Of the 43 comparisons, 12 were main effects and 31 were interactions. Of the 12 main effects, 8 were statistically significant at the .05 level. Of the 31 interactions, 9 were statistically significant at the .05 level. The results of the present study appeared to support the following generalizations: 1. Individuals with greatest irrational beliefs reported greater loneliness than those with least irrational beliefs. 2. Individuals with highest anxious over-concern reported greater loneliness than those with lowest anxious over concern. 3. Individuals with highest frustration reactivity reported greater loneliness than those with lowest frustration reactivity. 4. Individuals with highest self-expectation reported greater loneliness than individuals with lowest self-expectation. 5. An association between age and loneliness. 6. An association between gender and loneliness. 7. An association between marital status and loneliness. 8. An association between income and loneliness. 9. An association between living situation and loneliness. 10. An association between anxious over-concern and loneliness. 11. An association between frustration reactivity and loneliness, and 12. Interactions for marital status and age; income and age; age, income and irrational beliefs; living situation and dependency; gender and living situation; gender and frustration reactivity; gender, living situation, and high self-expectation; gender, living situation, and problem avoidance; and gender and irrational beliefs

Characterizing developmental prosopagnosia beyond face perception: Impaired recollection but intact familiarity recognition

Converging lines of research suggests that many developmental prosopagnosics (DPs) have impairments beyond face perception, but currently no framework exists to characterize these impaired mechanisms. One potential extra-perceptual deficit is that DPs encode/retrieve faces in a distinct manner from controls that does not sufficiently support individuation. To test this possibility, 30 DPs and 30 matched controls performed an old/new face recognition task while providing confidence ratings, to which a model-based ROC analysis was applied. DPs had significantly reduced recollection compared to controls, driven by fewer ‘high-confidence target’ responses, but intact familiarity. Recollection and face perception ability uniquely predicted objective and subjective prosopagnosia symptoms, together explaining 51% and 56% of the variance, respectively. These results suggest that a specific deficit in face recollection in DP may represent a core aspect of the difficulty in confidently identifying an individual by their face