971 resultados para Obstacle Avoidance


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In recent years. studies in behavioral pharmacology have shown the involvement of dopaminergic mechanisms in avoidance behavior as assessed by the two-way active avoidance test (CAR). Changes in dopaminergic transmission also occur in response to particularly threatening challenges. However, studies on the effects of benzodiazepine (BZD) drugs ill this test are still unclear. Given the interplay of dopamine and other neurotransmitters in the neurobiology of anxiety and schizophrenia the aim of this work was to evaluate the effects of systemic administration of midazolam, the dopaminergic agonist apomorphine, and the D(2) receptor antagonist sulpiride using the CAR, a test that shows good sensitivity to typical neuroleptic drugs. Whereas midazolam did not alter the avoidance response. apomorphine increased and sulpiride reduced them in this test. Escape was not affected by any drug treatments. Heightened avoidance was not associated with the increased motor activity caused by apomorphine. In contrast with the benzodiazepine midazolam, activation of post-synaptic D(2) receptors with apomorphine facilitates, whereas the D(2) receptor antagonism with sulpiride inhibited the acquisition of the avoidance behavior. Together, these results bring additional evidence for a role of D(2) mechanisms in the acquisition of the active avoidance. (C) 2009 Elsevier Inc. All rights reserved.

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Poor mobility has been associated with age-related deterioration in muscle strength. While previous work has examined the effects of improved strength on level walking, we have quantified the effects of a resistance-training program on obstructed gait tasks using biomechanical-dependent measures. Forty-five community-dwelling participants aged 62 years or older were randomised to either a control (n=16) or experimental group (n=29). The experimental subjects exercised for 24 weeks on a progressive resistance-training program designed to improve lower body strength. Dynamic strength was assessed at weeks 0 and 24 as well as specific laboratory gait kinetics and kinematics during stepping over an obstacle and negotiation of a raised surface set at 10, 20 and 30% of each subject's leg length.

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In both Canada and Australia the relevant governments found their initial legislative attempts to combat tax avoidance to be ineffective. In time in each country it was concluded that the respective general avoidance provisions were of limited application and avoidance provisions were of limited application and ineffective to combat the sophisticated tax avoidance schemes promoted by tax advisers. In Canada it was determined that Income Tax Act, R.S.C 1985, s. 245(1) would be repealed and replaced with a general anti-avoidance rule ('GAAR') contained in a new s. 245 ITA. The Australian government similarly decided to replace Income Tax Assessment Act, Cth. 1936, s. 260 with a new general anti-avoidance measure, Part IVA ITAA. This article compares and contrasts the Canadian and Australian GAARs. Through the evaluation of each regime the article seeks to identify which model is most effective. It will be sen which model is most effective. It will be seen that both regimes have some features that are preferable to the other and thus both GAARs might be improved by incorporating aspects of the other anti-avoidance model.

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Over the last m'o decades, university systems world-wide have been subject to government initiated, top-down restructures in the name of greater effectiveness, accountability and quality. Within this timefrome, government interest in university teaching has increased, and innovation and responsiveness in teaching have been increasingly prioritised by both government and university policies. AcademiC interest in the teaching has also increased. and much research and discussion has focused on defining teaching as a source of scholarship and expounding its role in the promotion of innovation, and in the recognition and rewarding of teaching work. In this paper, I draw on a study of academics' views, which I have reported at previous AARE conferences and elsewhere, to raise questions about recent and ongoing developments in the work environment of university educators.l raise the possibility that systems and processes whose express purpose is to facilitate and support university educators' efforts to improve teaching are, in fact. inhibiting innovative practice by institutionalising an aversion to risk that is anathema to innovation.

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Background and Purpose. Obstacle crossing is compromised following stroke. The purpose of this study was to quantify modifications during obstacle clearance following stroke.

Subjects. Twelve subjects with stroke and 12 subjects without stroke participated in the study.

Methods. Kinematic variables were measured while participants crossed a 4-cm-high obstacle. Subjects with stroke walked at a self-selected speed; subjects without stroke walked at a comparable speed and at a self-selected speed.

Results. Several modifications were observed following stroke with both groups walking at self-selected speeds. The affected lead limb was positioned closer to the obstacle before crossing. Affected trail-limb clearance over the obstacle was reduced. Both affected and unaffected lead and trail limbs landed closer to the obstacle after clearance. Swing time was increased in the affected lead limb after obstacle clearance. Fewer modifications were detected at matched walking speed; the trail limb still landed closer to the obstacle.

Discussion and Conclusion. Modifications during obstacle crossing following stroke may be partly related to walking speed. The findings raise issues of safety because people with stroke demonstrated reduced clearance of a 4-cm obstacle and limb placement closer to the obstacle after clearance.

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Within a climate of policy hysteria, it is often claimed that a 'preoccupation with performance' develops, focussing on individual success stories, resulting in 'fad-like waves of adoption and abandonment'. Within this increasing pace and intensity of reform, new networks are formed and new relationships developed, with key players taking on new forms of identity to morph into the constantly changing policy climate. Despite continued evidence of young people's pathways from school being more like mosaic than linear, new policy still seeks to define and limit the possible lines of flight and trajectories, closely managing the education and training of young people at risk. In Victoria, the major policy initiative has involved the establishment of LLENs, the local all purpose solution to young people who might not be sticking to the linear policy pathway. So are we involved in 'an avoidance game', filling up the post compulsory policy space with more and more policies, which in fact seek to continue to regulate and constrain young people, rather than supporting them? This paper interrogates the policies and practices which have created the learning networks, of the SGR LLEN through policy analysis and case studies.

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In this paper, we propose that there is a direct relationship between risk management and goods (or goal) promotion in the treatment of sexual offenders. We argue that the causal conditions required to promote specific goods are likely, in turn, to eliminate or modify dynamic risk factors (i.e., criminogenic needs). First, the concepts of risk and goals are briefly discussed and their important dimensions clarified. Second, the relationship between criminogenic needs and goals are analyzed in depth. Third, we further clarify our arguments by focusing on four classes of criminogenic needs recently identified in the sexual offending literature: sexual self-regulation, offense supportive cognitions, level of interpersonal functioning, and general self-management problems. Finally, we conclude the paper with some suggestions for future research and treatment.

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This thesis presents a solution to the problem of receiving a signal in the shadow and fringe areas. Theoretical and experimental investigation of the field behind an obstacle in a line of sight transmission path for UHF / microwave signals has resulted in a new approach to the analysis of electromagnetic fields in the shadow of an obstacle. Analysis using this approach showed the field to consist of varying amplitude and phase distribution. Additional analysis predicted an increase in received signal could be achieved if correlation between the field and antenna structure could be obtained. This was accomplished with a new antenna design. The thesis presents experimental and photographic evidence to support the theory. A novel technique involving the matching of the antenna structure to the field distribution, resulted in an increase of received signal in the diffracted field of up to 4 dB.

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Building demolition, as compared to building construction is always carried out as quickly and cheaply as possible. The nature of limited time and resources of the demolition project sometimes translate into poor work planning and safety precautions. In recent years, demolition work has become more complicated due to the high diversity of building types and there are various demolition techniques and strategies. It is important to have a clear understanding of the type of building to be demolished, the method to be used and risks involved to ensure proper work planning. Using historical data on demolition related accidents; this paper discusses the classification of injuries and causes of the accidents. To conclude, strategies for better understanding of demolition work and good practices of site safety are recommended.