Whirl flutter is an aeroelastic instability that affects aircraft with propellers/rotors. With their long and flexible rotor blades, tiltrotor aircraft are particularly susceptible. Whirl flutter is known to have destroyed aircraft and in the best case it constitutes a fatigue hazard. The complexity of whirl flutter analysis increases significantly with the addition of nonlinearities, due to the more complex dynamical behaviours that emerge as a result. Most whirl flutter stability analyses in current literature are grounded in linear theory, preventing the full discovery of the nonlinearities’ effects. Continuation and bifurcation methods (CBM) may instead be used to fully appreciate and analyse the effects of the presence of nonlinearities. Previous CBM-based work on nonlinear gimballed hub rotor-nacelle models, representing those found on tiltrotor aircraft, are capable of whirl flutter in parametric regions declared safe by linear analysis. Furthermore, it was found that they are capable of complex behaviours including limit cycle oscillations, quasi-periodic behaviour and even chaos, though the whirl flutter implications of such behaviours has not been explored. This paper investigates the impact of a smooth structural nonlinearity on the whirl flutter stability of a basic gimballed rotor-nacelle model, compared to its baseline linear stiffness version. A 9-DoF model with quasi-steady aerodynamics, a flexible wing and blades that can move both cyclically and collectively in both flapping and lead-lag motions, producing gimbal flap-like behaviour, was adopted from existing literature. A smooth stiffness nonlinearity was introduced in the blade flapping stiffness and CBM was used to find the new whirl flutter behaviours created by the presence of the nonlinearity. Time simulations, Poincaré sections and spectral analysis were then used to investigate the various behaviours found. This in turn allowed recommendations to be made concerning preferable and/or hazardous parameter combinations of use to the tiltrotor designer.

The Department of Transcultural Psychiatry (TCH) of the Regional Institute for Mental Health Care (Riagg) Rijnmond, Rotterdam, the Netherlands, set up an outreaching program, the Rif-Project, in response to the need for adjusting mental health care services to a more diverse and mobile client population while containing costs. In the past, TCH observed a decline in mental health status in Moroccan clients following their stay in Morocco, which was linked to uncoordinated eclectic health care consumption in Morocco, the pursuit of personally more acceptable diagnoses, somatic checkups or medication, and the occasional use of (stress-inducing) traditional healing methods. Rif-Project is based on the assumption of providing continuation of care to its Moroccan clients who spend their summer months in Morocco, through strategic positioning of TCH care-deliverers across the kingdom. Their activities include the continuation of the treatment program that was initiated in the Netherlands, visiting clients in their preferred environment and system, psycho-education and preventive activities. By monitoring their clients health care consumption, coordinating services in collaboration with local institutions, treatment interventions and psycho-education, TCH-workers were successful in providing and maintaining stability to their clients, which reduced the incidence of deterioration and crisis.

Although the linguistic and sociocultural benefits of class-based email projects are widely acknowledged, there has been little investigation of what occurs after a curriculum activity finishes. In particular, what factors promote continued communication or cause communication breakdown have received less empirical attention. This paper explores factors which promote the continuation or non-continuation of email interactions between Australian and Japanese students after the conclusion of their coursework email exchange task via the analysis of two class surveys, in addition to collected email interaction and interviews with four key students (two continuers and two non-continuers) who serve as case studies. The experiences of these four students who were randomly assigned partners in the project are contrasted with those of a fifth student, Lucas, who chose to communicate with a long-term Japanese friend for the assessment, instead of being paired by the teacher. A number of factors which influence continuation are identified, including past sojourn experience, existing social networks, perceptions towards the curriculum task and their partners, shared topics of interest, time constraints, explicit statement of desire to continue, and potentially face-threatening behaviour, and several recommendations for enhancing online exchanges are given.

Binary logic programs can be obtained from ordinary logic programs by a binarizing transformation. In most cases, binary programs obtained this way are less efficient than the original programs. (Demoen, 1992) showed an interesting example of a logic program whose computational behaviour was improved when it was transformed to a binary program and then specialized by partial deduction. The class of B-stratifiable logic programs is defined. It is shown that for every B-stratifiable logic program, binarization and subsequent partial deduction produce a binary program which does not contain variables for continuations introduced by binarization. Such programs usually have a better computational behaviour than the original ones. Both binarization and partial deduction can be easily automated. A comparison with other related approaches to program transformation is given.