Human resilience to forward falls: adaptation and transfer of stability control

Scoping fall resilience requires knowledge of factors enabling the neuromotor system to transfer stability control between different postural perturbations. This thesis addressed this objective in comprising three different studies on adults across the lifespan. The first study examined the intra- and inter-session reliability of recovery performance across 97 participants at several research centres using two different protocols of a clinical assessment method (lean-and-release task) simulating sudden anterior stability loss, i.e. gradual increase to maximal forward-lean angle vs. predefined lean angle. Independent of the protocol used and participants’ age, reliable assessment of common stability recovery performance parameters using the lean-and-release task could be confirmed. The second study used single exposures to both lean-and-release and a treadmill-based gait trip to investigate the association of recovery performance between unpractised perturbations. We revealed that recovery performance in one task could not significantly explain performance in the other task, indicating limited transfer of fall-resisting skills for anterior perturbations. The third study examined factors (particularly practising stability recovery responses with different perturbation magnitudes) that could elicit or limit transfer to unpractised perturbations. Participants walking on a treadmill were exposed to eight trip perturbations of either low or high magnitude or walked unperturbed (control group). To investigate transfer to unpractised anterior perturbations following walking tasks, all participants underwent a lean-and-release task and an overground trip. Adaptation in stability to repeated gait-perturbations did not lead to enhanced stability recovery in the lean-and-release task but did improve overground trip performance, independent of the practised perturbation magnitude. Lower limb joint angle differences between treadmill- and lean-and-release perturbations for the swing phase of recovery steps were more prolonged and greater as opposed to the comparison of the two gait perturbation tasks. In conclusion, the current work indicates that practising stability control enhances human resilience to unpractised perturbations which is not necessarily dependent on the perturbation magnitude but may partly be subject to similarity in motor response patterns between tasks

Two dimensional aerodynamic interference effects on oscillating airfoils with flaps in ventilated subsonic wind tunnels

The numerical computation of unsteady airloads acting upon thin airfoils with multiple leading and trailing-edge controls in two-dimensional ventilated subsonic wind tunnels is studied. The foundation of the computational method is strengthened with a new and more powerful mathematical existence and convergence theory for solving Cauchy singular integral equations of the first kind, and the method of convergence acceleration by extrapolation to the limit is introduced to analyze airfoils with flaps. New results are presented for steady and unsteady flow, including the effect of acoustic resonance between ventilated wind-tunnel walls and airfoils with oscillating flaps. The computer program TWODI is available for general use and a complete set of instructions is provided

How do complex phenotypes evolve? Solving the “gene for X” problem with atavisms, homeosis, and other evo-devo surprises

Helping students learn how major phenotypic shifts evolve is a major hurdle for biology educators. Fortuitously, teachers can exploit the oft-misunderstood “gene for X” concept to explain how evolution, and complex phenotypes, often turn on single changes to regulatory genes governing expression of structural genes during development. This explains how one gene can make a big difference, and relates microevolution relates to macroevolution, a frequent hang-up for evolution deniers. Although complex traits such as intelligence do not derive from a single gene, minor tweaks in gene regulators produce atavisms (sudden appearance of “throwback” features), homeotic mutants (whose altered features stem from shifts in developmental timing and location), and other major changes in organismal morphology. Biology educators must explain how evo-devo mechanisms profoundly shift the course of evolution and drive phenotypic change. An adult form does not evolve into another, but underlying development readily evolves

EAPC task force on education for psychologists in palliative care

It is argued that psychological aspects of care and psychosocial problems are essential components of palliative care. However, the provision of appropriate services remains somewhat arbitrary. Unlike medical and nursing care, which are clearly delivered by doctors and nurses respectively, psychological and psychosocial support in palliative care are not assigned exclusively to psychologists. It is generally expected that all professionals working in palliative care should have some knowledge of the psychological dynamics in terminal illness, as well as skills in communication and psychological risk assessment. On the one hand, palliative care education programmes for nurses and doctors comprise a considerable amount of psychological and psychosocial content. On the other hand, only a few palliative care associations provide explicit information on the role and tasks of psychologists in palliative care. Psychologists’ associations do not deal much with this issue either. If they refer to it at all, it is in the context of the care of the aged, end-of-life care or how to deal with grief

Develop and test fuel cell powered on-site integrated total energy system

Test results are presented for a 24 cell, two sq ft (4kW) stack. This stack is a precursor to a 25kW stack that is a key milestone. Results are discussed in terms of cell performance, electrolyte management, thermal management, and reactant gas manifolding. The results obtained in preliminary testing of a 50kW methanol processing subsystem are discussed. Subcontracting activities involving application analysis for fuel cell on site integrated energy systems are updated

Develop and test fuel cell powered on-site integrated total energy systems: Phase 3, full-scale power plant development

A 25 cell stack of the 13 inch x 23 inch cell size (about 4kW) remains on test after 6000 hours, using simulated reformate fuel. A similar stack was previously shut down after 7000 hours on load. These tests were carried out for the purpose of assessing the durability of fuel cell stack components developed through the end of 1983. In light of the favorable results obtained, a 25kW stack that will contain 175 cells of the same size is being constructed using the same technology base. The components for the 25kW stack have been completed. A methanol steam reformer with a design output equivalent to 50kW has been constructed to serve as a hydrogen generator for the 25kW stack. This reformer and the balance of the fuel processing sub system are currently being tested and debugged. The stack technology development program focused on cost reduction in bipolar plates, nonmetallic cooling plates, and current collecting plates; more stable cathode catalyst support materials; more corrosion resistant metal hardware; and shutdown/start up tolerance

Determining the fate and toxicity of polycyclic aromatic hydrocarbons associated with coal-tar and other carbonaceous material particles in urban lakes

U.S. Department of the InteriorU.S. Geological SurveyOpe

Develop and test fuel cell powered on-site integrated total energy systems

On-going testing of an 11 cell, 10.7 in. x 14 in. stack (about 1 kW) reached 2600 hours on steady load. Nonmetallic cooling plates and an automated electrolyte replenishment system continued to perform well. A 10 cell, 10.7 in. x 14 in. stack was constructed with a modified electrolyte matrix configuration for the purpose of reducing cell IR loss. The desired effect was achieved, but the general cell performance level was irregular. Evaluation is continuing. Preparations for a long term 25 cell, 13 in. x 23 in. test stack (about 4 kW) approached completion. Start up in early May 1984 is expected

Develop and test fuel cell powered on site integrated total energy sysems: Phase 3: Full-scale power plant development

A 25-cell stack of the 13 inch x 23 inch cell size (about 4kW) remains on test after 8300 hours, using simulated reformate fuel. A similar stack was previously shut down after 7000 hours on load. These tests have been carried out for the purpose of assessing the durability of fuel cell stack components developed through the end of 1983. A 25kW stack containing 175 cells of the same size and utilizing a technology base representative of the 25-cell stacks has been constructed and is undergoing initial testing. A third 4kW stack is being prepared, and this stack will incorporate several new technology features