Harmonic Forcing of Damped Non-homogeneous Euler-Bernoulli Beams

This work is an extension of previous studies on vibrations of non-homogeneous structures. It also explores the use of logistic functions. In the studies, frequency response functions (FRFs) were determined for segmented structures, using analytic and numerical approaches. The structures are composed of stacked cells, which are made of different materials and may have different geometric properties. Here the steady state response, due to harmonic forcing, of a segmented damped Euler-Bernoulli beam is investigated. FRFs for the system are sought via two methods. The first uses the displacement differential equations for each segment. Boundary and interface continuity conditions are used to determine the constants involved in the solutions. Then the response, as a function of forcing frequency, can be obtained. This procedure is unwieldy. In addition, determining particular integrals can become cumbersome for arbitrary spatial variations. The second approach uses logistic functions to model the segment discontinuities. The result is a single partial differential equation with variable coefficients. Approaches for numerical solutions are then developed with the aid of MAPLE® software. For free-fixed boundary conditions, spatially constant force and viscous damping, excellent agreement is found between the methods. The numerical approach is then used to obtain the FRF for the case of a spatially varying force

Trauma and mental health of medics in eastern Myanmar’s conflict zones: a cross-sectional and mixed methods investigation

BACKGROUND: In conflict and disaster settings, medical personnel are exposed to psychological stressors that threaten their wellbeing and increase their risk of developing burnout, depression, anxiety, and PTSD. As lay medics frequently function as the primary health providers in these situations, their mental health is crucial to the delivery of services to afflicted populations. This study examines a population of community health workers in Karen State, eastern Myanmar to explore the manifestations of health providers’ psychological distress in a low-resource conflict environment. METHODS: Mental health screening surveys were administered to 74 medics, incorporating the 12-item general health questionnaire (GHQ-12) and the posttraumatic checklist for civilians (PCL-C). Semi-structured qualitative interviews were conducted with 30 medics to investigate local idioms of distress, sources of distress, and the support and management of medics’ stressors. RESULTS: The GHQ-12 mean was 10.7 (SD 5.0, range 0–23) and PCL-C mean was 36.2 (SD 9.7, range 17–69). There was fair internal consistency for the GHQ-12 and PCL-C (Cronbach’s alpha coeffecients 0.74 and 0.80, respectively) and significant correlation between the two scales (Pearson’s R-correlation 0.47, P<0.001). Qualitative results revealed abundant evidence of stressors, including perceived inadequacy of skills, transportation barriers, lack of medical resources, isolation from family communities, threats of military violence including landmine injury, and early life trauma resulting from conflict and displacement. Medics also discussed mechanisms to manage stressors, including peer support, group-based and individual forms of coping. CONCLUSIONS: The results suggest significant sources and manifestations of mental distress among this under-studied population. The discrepancy between qualitative evidence of abundant stressors and the comparatively low symptom scores may suggest marked mental resilience among subjects. The observed symptom score means in contrast with the qualitative evidence of abundant stressors may suggest the development of marked mental resilience among subjects. Alternatively, the discrepancy may reflect the inadequacy of standard screening tools not validated for this population and potential cultural inappropriateness of established diagnostic frameworks. The importance of peer-group support as a protective factor suggests that interventions might best serve healthworkers in conflict areas by emphasizing community- and team-based strategies