Stable Magnetostatic Solitons in Yttrium Iron Garnet Film Waveguides for Tilted in-Plane Magnetic Fields

The possibility of nonlinear pulses generation in Yttrium Iron Garnet thin films for arbitrary direction between waveguide and applied static in-plane magnetic field is considered. Up to now only the cases of in-plane magnetic fields either perpendicular or parallel to waveguide direction have been studied both experimentally and theoretically. In the present paper it is shown that also for other angles (besides 0 or 90 degrees) between a waveguide and static in-plane magnetic field the stable bright or dark (depending on magnitude of magnetic field) solitons could be created.Comment: Phys. Rev. B (accepted, April 1, 2002

Minutes 1875

https://place.asburyseminary.edu/freemethodistminutesyearbooks/1013/thumbnail.jp

Direct Hopf Bifurcation in Parametric Resonance of Hybridized Waves

We study parametric resonance of interacting waves having the same wave vector and frequency. In addition to the well-known period-doubling instability we show that under certain conditions the instability is caused by a Hopf bifurcation leading to quasiperiodic traveling waves. It occurs, for example, if the group velocities of both waves have different signs and the damping is weak. The dynamics above the threshold is briefly discussed. Examples concerning ferromagnetic spin waves and surface waves of ferro fluids are discussed.Comment: Appears in Phys. Rev. Lett., RevTeX file and three postscript figures. Packaged using the 'uufiles' utility, 33 k

Who I Am: The Meaning of Early Adolescents’ Most Valued Activities and Relationships, and Implications for Self-Concept Research

Self-concept research in early adolescence typically measures young people’s self-perceptions of competence in specific, adult-defined domains. However, studies have rarely explored young people’s own views of valued self-concept factors and their meanings. For two major self domains, the active and the social self, this mixed-methods study identified factors valued most by 526 young people from socioeconomically diverse backgrounds in Ireland (10-12 years), and explored the meanings associated with these in a stratified subsample (n = 99). Findings indicate that self-concept scales for early adolescence omit active and social self factors and meanings valued by young people, raising questions about content validity of scales in these domains. Findings also suggest scales may under-represent girls’ active and social selves; focus too much on some school-based competencies; and, in omitting intrinsically salient self domains and meanings, may focus more on contingent (extrinsic) rather than true (intrinsic) self-esteem

High-sensitivity cardiac troponin I improves cardiovascular risk prediction in older men: HIMS (The Health in Men Study)

Background: The Framingham Risk Score estimates the 10-year risk of cardiovascular events. However, it performs poorly in older adults. We evaluated the incremental benefit of adding high-sensitivity cardiac troponin I (hs-cTnI) to the Framingham Risk Score. Methods and Results: The HIMS (Health in Men Study) is a cohort study of community-dwelling men aged 70 to 89 years in Western Australia. Participants were identified from the electoral roll, with a subset undergoing plasma analysis. Hs-cTnI (Abbott Architect i2000SR) was measured in 1151 men without prior cardiovascular disease. The Western Australia Data Linkage System was used to identify incident cardiovascular events. After 10 years of follow-up, 252 men (22%) had a cardiovascular event (CVE+) and 899 did not (CVE–). The Framingham Risk Score placed 148 (59%) CVE+ and 415 (46%) CVE– in the high-risk category. In CVE– men, adding hs-cTnI affected the risk categories of 244 (27.2%) men, with 64.8% appropriately reclassified to a lower and 35.2% to a higher category, which decreased the number of high-risk men in the CVE– to 39%. In CVE+ men, adding hs-cTnI affected the risk categories of 61 (24.2%), with 50.8% appropriately reclassified to a higher and 49.2% to a lower category and 82.5% remaining above the 15% risk treatment threshold. The net reclassification index was 0.305 (P<0.001). Adding hs-cTnI increased the C-statistic modestly from 0.588 (95% CI, 0.552–0.624) to 0.624 (95% CI, 0.589–0.659) and improved model fit (likelihood ratio test, P<0.001). Conclusions: Adding hs-cTnI to the Framingham Risk Score provided incremental prognostic benefit in older men, especially aiding reclassification of individuals into a lower risk category

Recent advances in symmetric and network dynamics

We summarize some of the main results discovered over the past three decades concerning symmetric dynamical systems and networks of dynamical systems, with a focus on pattern formation. In both of these contexts, extra constraints on the dynamical system are imposed, and the generic phenomena can change. The main areas discussed are time-periodic states, mode interactions, and non-compact symmetry groups such as the Euclidean group. We consider both dynamics and bifurcations. We summarize applications of these ideas to pattern formation in a variety of physical and biological systems, and explain how the methods were motivated by transferring to new contexts René Thom's general viewpoint, one version of which became known as “catastrophe theory.” We emphasize the role of symmetry-breaking in the creation of patterns. Topics include equivariant Hopf bifurcation, which gives conditions for a periodic state to bifurcate from an equilibrium, and the H/K theorem, which classifies the pairs of setwise and pointwise symmetries of periodic states in equivariant dynamics. We discuss mode interactions, which organize multiple bifurcations into a single degenerate bifurcation, and systems with non-compact symmetry groups, where new technical issues arise. We transfer many of the ideas to the context of networks of coupled dynamical systems, and interpret synchrony and phase relations in network dynamics as a type of pattern, in which space is discretized into finitely many nodes, while time remains continuous. We also describe a variety of applications including animal locomotion, Couette–Taylor flow, flames, the Belousov–Zhabotinskii reaction, binocular rivalry, and a nonlinear filter based on anomalous growth rates for the amplitude of periodic oscillations in a feed-forward network