Nonlinear effects in the propagation of optically generated magnetostatic volume mode spin waves

Recent experimental work has demonstrated optical control of spin wave emission by tuning the shape of the optical pulse (Satoh et al.\ Nature Photonics, 6, 662 (2012)). We reproduce these results and extend the scope of the control by investigating nonlinear effects for large amplitude excitations. We observe an accumulation of spin wave power at the center of the initial excitation combined with short-wavelength spin waves. These kind of nonlinear effects have not been observed in earlier work on nonlinearities of spin waves. Our observations pave the way for the manipulation of magnetic structures at a smaller scale than the beam focus, for instance in devices with all-optical control of magnetism.Comment: Added new figures to further illustrate the nonlinear effects to show time evolution and spectral flow. Added references. Changed perspective on nonlinear effects w.r.t. applicability of NSE. Added acknowledgemen

Awareness of risk factors for loneliness among third agers

Awareness of risk factors for loneliness is a prerequisite for preventive action. Many risk factors for loneliness have been identified. This paper focuses on two: poor health and widowhood. Preventive action by developing a satisfying social network requires time and effort and thus seems appropriate for people unexposed to risk factors, i.e. third agers and non-lonely persons. The third age is the period in old age after retirement, before people's social relationships deteriorate. This paper addresses three questions: Are older adults aware of poor health and widowhood as risk factors for loneliness? Are there differences in awareness between third and fourth agers? Are there differences in awareness between lonely and non-lonely older adults? After being introduced to four vignette persons, 920 respondents from the Longitudinal Aging Study Amsterdam were asked whether they expected these persons to be lonely. Older adults, especially third agers, expected peers exposed to the risk factors to be lonely more often than peers who were unexposed. The results indicate that awareness of loneliness-provoking factors is high among third agers, which is a first step towards taking actions to avoid loneliness. Compared to lonely older adults, non-lonely ones expected peers to be lonely less often, suggesting the latter's lower awareness of the risk factors. The results provide evidence for policy makers and practitioners that combating loneliness might require early action

Physical health and the onset and persistence of depression in older adults: an eight-wave prospective community based study.

Background. Poor physical health has long been recognized to be one of the most important risk factors for depression in older adults. Since many aspects of physical health can be targeted for improvement in primary care, it is important to know whether physical health problems predict the onset and/or the persistence of depression. Methods. The study is based on a sample which at the outset consisted of 327 depressed and 325 non-depressed older adults (55-85) drawn from a larger random community-based sample in the Netherlands. Depression was measured using the Center for Epidemiologic Studies Depression scale (CES-D) at eight successive waves. Results. From all incident episodes, the majority (57%) was short-lived. These short episodes could generally not be predicted by physical health problems. The remaining incident episodes (43%) were not short-lived and could be predicted by poor physical health. Chronicity (34%) was also predicted by physical health problems. Conclusions. The study design with its frequent measurements recognized more incident cases than previous studies; these cases however did have a better prognosis than is often assumed. The prognosis of prevalent cases was rather poor. Physical health problems were demonstrated to be a predictor of both the onset and the persistence of depression. This may well have implications for prevention and intervention