The effects of improved strength on obstacle negotiation in community-living older adults

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.

Control of lead and trail limbs during obstacle crossing following stroke

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.

Technique for improving the reception of scattering signal behind an obstacle

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.

Radical epistemological skepticism about justified belief

"Radical epistemological skepticism" designates the philosophical position that all our beliefs, and knowledge based upon them, are groundless. Skeptics claims have been recorded throughout history and, despite their threat to the security of human knowledge, they endure. The thesis hypothesises that skepticism is a consequence of our development of symbolic capability.

A Smartphone-based obstacle sensor for the visually impaired

In this paper, we present a real-time obstacle detection system for the mobility improvement for the visually impaired using a handheld Smartphone. Though there are many existing assistants for the visually impaired, there is not a single one that is low cost, ultra-portable, non-intrusive and able to detect the low-height objects on the floor. This paper proposes a system to detect any objects attached to the floor regardless of their height. Unlike some existing systems where only histogram or edge information is used, the proposed system combines both cues and overcomes some limitations of existing systems. The obstacles on the floor in front of the user can be reliably detected in real time using the proposed system implemented on a Smartphone. The proposed system has been tested in different types of floor conditions and a field trial on five blind participants has been conducted. The experimental results demonstrate its reliability in comparison to existing systems.

Bourdieu and educational research: thinking tools, relational thinking, beyond epistemological innocence

The main aim of this chapter is to provide an introduction to the theoretical work of Pierre Bourdieu, and to outline different ways in which Bourdieu’s work is influential and has been engaged with in education research and to suggest implicitly the usefulness of this work for educational researchers. In order to do this, we draw on a range of Bourdieu’s own writing published singly or with colleagues, emphasising in particular his engagements with education. Part of our treatment also deals with his wider writing that has subsequently been influential for education researchers, and in particular Bourdieu’s anthropological writing and account of practice (Bourdieu 1977, 1990), his approach to social class and cultural issues, his account of the judgement of taste and distinctions (Bourdieu, 1984), and his later politically focused writing (Bourdieu, 1989/1996, 2003, 2004c, 2005a).

Towards understanding epistemological assumptions of history teacher educators: my experience with phenomenological enquiry

This paper draws upon the methodological aspect of my thesis project completed in June 2007. At the center of the research problem was the question: How do history teacher educators (HTEs) in Bahir Dar University comprehend the sources and nature of historical knowledge? Phenomenological approach to research was employed in an attempt to explicate invariant structures of their epistemic assumptions of history as a school subject. Accordingly, with six purposefully selected educators as research participants, in the two-month time field work, in- depth interview and essay questions for personal text were used to gather qualitative data. Then, the data were analyzed thematically using an adapted six-phase model and interpretive themes emerged as findings of the study. And it was learnt that the educators have a very muddled conception and unquestioned assumptions on the nature and sources of historical knowledge. With this, also phenomenological enquiry, with difficulties and rewards of its own, was found to be an appropriate strategy to understand personal meaning and beliefs of the educator with regard to disciplinary knowledge of history. The paper, therefore, describes the way I employed phenomenological research approach to understand the case, and presents my personal experience of it as a beginner education researcher.

Epistemological pluralism in research synthesis methods

The purpose of research synthesis is to produce new knowledge by making explicit connections and tensions between individual study reports that were not visible before. Every effort of synthesizing research is inevitably premised on certain epistemological assumptions. It is crucial that research synthesists reflect critically on how their epistemological positioning enables them to pursue certain purposes while preventing them from pursuing other purposes. The literature on research synthesis methods is dominated by publications premised on positivist assumptions. The rhetoric of systematic reviews, best-evidence synthesis and What Works Clearinghouse privileges syntheses with positivist orientations. Contesting the hegemony of positivist research syntheses, this paper makes a case for research syntheses that are informed by diverse epistemological orientations. It illuminates how research syntheses with distinct epistemological orientations can serve complementary, equally worthwhile, purposes.

Justice, community, and dialogue in international relations

This book is concerned with the issue of cultural diversity and international morality. The author asks whether cultural diversity presents an obstacle to the development of ethical codes which could be acceptable to cultures around the world. He argues that the human capacity to engage in conversation and the ability to understand each other despite linguistic and cultural differences can provide the basis for the development of a world-wide, cosmopolitan moral community. Conversation can be a moral act, in which participants treat each other as equals despite their differences.

Effects of approach velocity and foot-target characteristics on the visual regulation of step length

Two questions emerge from the literature concerning the perceptual-motor processes underlying the visual regulation of step length. The first concerns the effects of velocity on the onset of visual control (VCO), when visual regulation of step length begins during goal-directed locomotion. The second concerns the effects of different obstacles such as a target or raised surface on step length regulation. In two separate experiments, participants (Experiment 1 & 2: n=12, 6 female, 6 male) walked, jogged, or sprinted towards an obstacle along a 10 m walkway, consisting of two marker-strips with alternating black and white 0.50 m markings. Each experiment consisted of three targeting or obstacle tasks with the requirement to both negotiate and continue moving (run-through) through the target. Five trials were conducted for each task and approach speed, with trials block randomised between the six participants of each gender. One 50 Hz video camera panned and filmed each trial from an elevated position, adjacent to the walkway. Video footage was digitized to deduce the gait characteristics. Results for the targeting tasks indicate a linear relationship between approach velocity and accuracy of final foot placement (r=0.89). When foot placement was highly constrained by the obstacle step length shortened during the entire approach. VCO was found to occur at an earlier tau-margin for lower approach velocities for both experiments, indicating that the optical variable ‘tau' is affected by approach velocity. A three-phase kinematic profile was found for all tasks, except for the take-off board condition when sprinting. Further research is needed to determine whether this velocity affect on VCO is due to ‘whole-body' approach velocity or whether it is a function of the differences between gait modes.

The relationship between lower body strength and obstructed gait in community-dwelling older adults

OBJECTIVES: To determine the relationship between lower body strength of community-dwelling older adults and the time to negotiate obstructed gait tasks.

DESIGN: A correlational study.

SETTING: The Biomechanics Laboratory, Deakin University, Australia.

PARTICIPANTS: Twenty-nine women and 16 men aged 62 to 88 were recruited using advertisements placed in local newspapers. The participants were independent community dwellers, healthy and functionally mobile.

MEASUREMENTS: Maximal isometric strength of the knee extensors and dynamic strength of the hip extensors, hip flexors, hip adductors, hip abductors, knee extensors, knee flexors, and ankle plantar flexors were assessed. The times to negotiate four obstructed gait tasks at three progressively challenging levels on an obstacle course and to complete the course were recorded. The relationship between strength and the crossing times was explored using linear regression models.

RESULTS: Significant associations between the seven strength measures and the times to negotiate each gait task and to walk the entire course at each level were obtained (r = -0.38 to -0.55; P < .05). In addition, the percentage of the variance explained by strength (R2), consistently increased as a function of the progressively challenging level. This increase was particularly marked for the stepping over task (R2 = 19.3%,25.0%, and 27.2%, for levels 1, 2, and 3, respectively) and the raised surface condition (R2 = 17.1%,21.1%, and 30.8%, for levels 1,2, and 3, respectively) .

CONCLUSION: The findings of the study showed that strength is a critical requirement for obstructed locomotion. That the magnitude of the association increased as a function of the challenging levels suggests that intervention programs aimed at improving strength would potentially be effective in helping community-dwelling older adults negotiate environmental gait challenges.

Kivy on justifying music in liberal education

Within analytical aesthetic circles, Peter Kivy is best known for re-igniting the debate inaugurated by Eduard Hanslick over the issue of whether or not music of the purely instrumental or absolute kind can be said to express a content, and, if so, whether or not listeners' emotional responses to it bear any relation to that content. Kivy's particular contribution countenances the possibility of interpreting the appearance of a musical work as expressive - be it the percussive Allegro barbara [1911] by Bela Bartok or the lyrical Adagio for Strings {1936] by Samuel Barber - without having to presume that music itself, being non-sentient by nature, possesses any emotional, subjective state.  This short essay, however, will critically examine a rather neglected facet of Kivy's prolific writings. In a relatively recent attempt to justify the place of purely instrumental music in liberal education without drawing upon the above-mentioned notion of expressiveness, Kivy reconceptualizes the matter in a manner that significantly shifts us from the dominant epistemological arena of debate. No longer are we to dispute the place of music within the terms set by the highly influential forms-of-knowledge approach revived by P.H. Hirst a generation ago and currently under revision by Jim McKenzie in terms of forms of argumentative discourse. But before first surveying and then critically assessing Kivy's proposal, perhaps we should briefly remind ourselves of the contrasting frame of reference associated with Hirst.