Planetary explorer liquid propulsion study

An analytical evaluation of several candidate monopropellant hydrazine propulsion system approaches is conducted in order to define the most suitable configuration for the combined velocity and attitude control system for the Planetary Explorer spacecraft. Both orbiter and probe-type missions to the planet Venus are considered. The spacecraft concept is that of a Delta launched spin-stabilized vehicle. Velocity control is obtained through preprogrammed pulse-mode firing of the thrusters in synchronism with the spacecraft spin rate. Configuration selection is found to be strongly influenced by the possible error torques induced by uncertainties in thruster operation and installation. The propulsion systems defined are based on maximum use of existing, qualified components. Ground support equipment requirements are defined and system development testing outlined

Recent Decisions

Comments on recent decisions by William F. Donahue, Frank G. Matavovsky, Thos. L. McKevitt, Joseph Kirincich, and Maurice W. Lee

How is the audit of therapy intensity influencing rehabilitation in inpatient stroke units in the UK? An ethnographic study.

OBJECTIVES: Occupational therapy, physiotherapy and speech and language therapy are central to rehabilitation after a stroke. The UK has introduced an audited performance target: that 45 min of each therapy should be provided to patients deemed appropriate. We sought to understand how this has influenced delivery of stroke unit therapy. DESIGN: Ethnographic study, including observation and interviews. The theoretical framework drew on the work of Lipsky and Power, framing therapists as 'street level bureaucrats' in an 'audit society'. SETTING: Stroke units in three English hospitals. PARTICIPANTS: Forty-three participants were interviewed, including patients, therapists and other staff. RESULTS: There was wide variation in how therapy time was recorded and in decision-making regarding which patients were 'appropriate for therapy' or auditable. Therapists interpreted their roles differently in each stroke unit. Therapists doubted the validity of the audit results and did not believe their results reflected the quality of services they provided. Some assumed their audit results would inform commissioning decisions. Senior therapy leaders shaped priorities and practices in each therapy team. Patients were inactive outside therapy sessions. Patients differed regarding the quantity of therapy they felt they needed but consistently wanted to be more involved in decisions and treated as individuals

Contributors to the May Issue/Notes

Notes by Thos. L. McKevitt, John A. Berry, Paul F. O\u27Neil, William J. Klima, Jr., Robert Devine, Donald F. Wise, Joseph A. McCabe, and Martin P. Torborg

Contributors to the May Issue/Notes

Notes by Thos. L. McKevitt, John A. Berry, Paul F. O\u27Neil, William J. Klima, Jr., Robert Devine, Donald F. Wise, Joseph A. McCabe, and Martin P. Torborg

How is rehabilitation with and without an integrated self-management approach perceived by UK community-dwelling stroke survivors? A qualitative process evaluation to explore implementation and contextual variations.

OBJECTIVE: Self-management programmes could support long-term needs after stroke and using methods integrated into rehabilitation is one option. To explore theoretical assumptions and possible mechanisms of implementation a process evaluation was delivered alongside a cluster trial which has demonstrated feasibility of an integrated self-management programme (Bridges SMP) in community-dwelling stroke survivors. This paper aims to show the extent to which experiences from stroke survivors receiving rehabilitation in control (usual care) and intervention (integrated self-management) sites reflected the differences in rehabilitation received and whether their understandings aligned with the self-management approach employed. DESIGN: Semistructured qualitative interviews carried out as part of a process evaluation analysed thematically. SETTING: Study was based in South London; all interviews were carried out in participants' home setting. PARTICIPANTS: 22 stroke participants recruited; 12 from integrated self-management sites and 10 from usual care sites. RESULTS: All participants revealed shared appreciation of knowledge and support from therapists but subtle differences emerged between sites in respect to perceptions about responsibility, control and how previous experiences were used. Accounts depicted a variance regarding who had structured and planned their rehabilitation, with greater flexibility about content and involvement perceived by participants from the integrated self-management sites. They also provided accounts and experiences which aligned with principles of the intervention, such as self-discovery and problem-solving. CONCLUSIONS: The findings reflect our theoretical assumptions and possible mechanisms of implementation that rehabilitation with a focus on supporting self-management is reflected in accounts and understandings of stroke survivors. Taken together with our previous research this justifies evaluating the effectiveness of Bridges SMP in a larger sample to further contribute to an understanding of the functioning of the intervention, implementation, contextual factors and mechanisms of impact. TRIAL REGISTRATION NUMBER: ISRCTN42534180; Post-results

Exploring stroke survivors' and physiotherapists' views of self-management after stroke: a qualitative study in the UK.

OBJECTIVES: Stroke is a sudden-onset condition with long-term consequences. Self-management could help address long-term consequences of stroke. Stroke survivors' and health professionals' views of self-management may vary, limiting the successful introduction of self-management strategies. This paper explores stroke survivors' and physiotherapists' views of self-management, focusing on what self-management means, and factors perceived to enable and hinder self-management after stroke, to draw out implications for policy, practice and future research. DESIGN: Qualitative study using semistructured interviews and a thematic analysis approach. SETTING: Stroke unit and community stroke-rehabilitation services in London, UK. PARTICIPANTS: 13 stroke survivors (8 men and 5 women; aged 53-89 years) admitted to a London stroke unit. 13 physiotherapists: 8 working in an inpatient stroke unit and 5 in community rehabilitation. RESULTS: Key differences were evident in how self-management was understood between these groups. Stroke survivors were unfamiliar with the term self-management, but most could provide their own definition and relate to the term, and understood it as care of the self: 'doing things for yourself' and 'looking after yourself'. They did not recognise self-management as part of their care, but valued therapists as encouraging experts in supporting their recovery after stroke. Physiotherapists commonly understood self-management as a process in which stroke survivors were expected to take an active role in their rehabilitation and manage their recovery and health, with different understandings of self-management among physiotherapists shaped by the context in which they worked. They reported that individual, social and organisational factors enable and hinder self-management after stroke, with individual and organisational barriers particularly evident in the early stages. CONCLUSIONS: If self-management support approaches are to be used, further work is required to explore the language and strategies used by professionals to support self-management, and the barriers to supporting self-management at different time points after stroke