Solitons in a parametrically driven damped discrete nonlinear Schr\"odinger equation

We consider a parametrically driven damped discrete nonlinear Schr\"odinger (PDDNLS) equation. Analytical and numerical calculations are performed to determine the existence and stability of fundamental discrete bright solitons. We show that there are two types of onsite discrete soliton, namely onsite type I and II. We also show that there are four types of intersite discrete soliton, called intersite type I, II, III, and IV, where the last two types are essentially the same, due to symmetry. Onsite and intersite type I solitons, which can be unstable in the case of no dissipation, are found to be stabilized by the damping, whereas the other types are always unstable. Our further analysis demonstrates that saddle-node and pitchfork (symmetry-breaking) bifurcations can occur. More interestingly, the onsite type I, intersite type I, and intersite type III-IV admit Hopf bifurcations from which emerge periodic solitons (limit cycles). The continuation of the limit cycles as well as the stability of the periodic solitons are computed through the numerical continuation software Matcont. We observe subcritical Hopf bifurcations along the existence curve of the onsite type I and intersite type III-IV. Along the existence curve of the intersite type I we observe both supercritical and subcritical Hopf bifurcations.Comment: to appear in "Spontaneous Symmetry Breaking, Self-Trapping, and Josephson Oscillations in Nonlinear Systems", B.A. Malomed, ed. (Springer, Berlin, 2012

Horizontal Violence Effect on Nurse Retention

Horizontal violence is known by a variety of terms such as lateral violence, bullying, and incivility. Christie and Jones (2014) describe lateral violence as a problem in nursing where a behavior is demonstrated through harmful actions that occur between nurses. Studies have revealed how horizontal violence affects nurse retention. Horizontal violence is a relevant issue in the healthcare community, yet often goes undiscussed. Walrafen (2012) explains that an outcome of horizontal violence in nursing is directly proportional to a decrease in retention of nurses. Sherman (2012) proclaimed that nurses who are subjected to horizontal violence have low self-esteem, depression, excessive sick leave, and poor morale. As Wilson (2011) identified nurses, who witness or experience horizontal violence have an increased desire to leave the organization where the bullying takes place. Horizontal violence is a pervasive source of occupational stress with physical, psychological, and organizational consequences (Hauge, et al, 2010). Roy (2007) describes this as an unkind, discourteous manner in which nurses relate to their colleagues. As nurses seek to perform their daily tasks, other co-workers may embarrass them for their lack of knowledge, tease them as they participate in informal cliques, or demean them for their technique (Bakker, 2012). Creating excuses, taunting, and refusing to share information, nursing education or knowledge are examples of horizontal violence (Ball, 1996)

Race and Income Disparities in Disaster Preparedness in Old Age

Objective: Older adults are one of the most vulnerable populations impacted by disasters and communities continue to struggle addressing preparedness. This study investigated to what extent income status and race/ethnicity in old age interplayed with disaster preparedness. Methods: Data came from the 2010 Health and Retirement Study, a nationally representative panel survey of older Americans over 51 years old. Our sample was restricted to respondents who participated in a special survey about disaster preparedness (N=1,705). Disaster preparedness was measured as a score, which includes 13 variables related to personal, household, program, and medical preparedness. Race/ethnicity was categorized by White, Black, and Hispanic. Low income was defined as below 300% of the federal poverty line. OLS regression was used to examine the main and interaction effects of race/ethnicity and lower income status on disaster preparedness scores. Results: We found that older adults in lower income status had lower preparedness level than those in higher income (Coef.=-0.318, p\u3c.01). Hispanics tend to be less prepared compared to White and African Americans (Coef.=--0.548, p\u3c.001). Preparedness of Black elders was not significantly different from that of Whites. However, interestingly, Black elders in lower income status were significantly less prepared for disaster than other groups (Coef.=-0.520, p\u3c.05). We did not find significant interaction effects between Hispanic and lower income status on disaster preparedness. Discussion. This study identified vulnerable subgroups of older adults for disaster preparedness and suggests that preparedness programs should target minority and low income elders, particularly Hispanics and low income Black elders

Serological survey of anti-group A rotavirus IgM in UK adults

Rotaviral associated disease of infants in the UK is seasonal and infection in adults not uncommon but the relationship between these has been little explored. Adult sera collected monthly for one year from routine hospital samples were screened for the presence of anti-group A rotavirus immunoglobulin M class antibodies as a marker of recent infection. Anti-rotavirus IgM was seen in all age groups throughout the year with little obvious seasonal variation in the distribution of antibody levels. IgM concentrations and the proportion seropositive above a threshold both increased with age with high concentrations consistently observed in the elderly. Results suggest either high infection rates of rotavirus in adults, irrespective of seasonal disease incidence in infants, IgM persistence or IgM cross-reactivity. These results support recent evidence of differences between infant and adult rotavirus epidemiology and highlight the need for more extensive surveys to investigate age and time related infection and transmission of rotavirus

Electromagnetic design search and optimisation of photonic bandgap devices on distributed computational resources

Photonic crystals are devices with periodically modulated dielectric constant, designed to exhibit band gaps in a frequency spectrum in which electromagnetic waves cannot propagate. Tuning the properties of these structures to achieve precise band gaps before fabrication is of high interest to photonic crystal manufacturers. In this paper, we present the process of finding and optimising a photonic crystal design using a high-throughput Condor-based compute cluster and transparent database technology for easy storage, retrieval and reuse of the created designs. We also demonstrate how a band gap diagram can easily be obtained on a compute cluster when using the developed user interface technology. The optimisation process can easily be adapted to other problem area