Dafna Merom and Robert Korycinski
The mid-1990s marked a paradigm shift in the way physical activity is promoted, and walking is now considered the most suitable type of physical activity for widespread promotion…
Abstract
The mid-1990s marked a paradigm shift in the way physical activity is promoted, and walking is now considered the most suitable type of physical activity for widespread promotion. Accurate measurement underpins public health practice, hence the aims of this chapter are to: (1) provide a typology for the measurement of walking; (2) review methods to assess walking; (3) present challenges in defining walking measures; (4) identify issues in selecting instruments for the evaluation of walking and (5) discuss current efforts to overcome measurement challenges and methodological limitations. The taxonomy of walking indicates that secondary purpose walking is a more complex set of behaviours than primary purpose walks. It has many purposes and no specific domain or intensity, may lack regularity, and therefore poses greater measurement challenges. Objective measurement methods, such as accelerometers, pedometers, smartphones and other electronic devices, have shown good approximation for walking energy expenditure, but are indirect methods of walking assessment. Global Positioning System technology, the ‘Smartmat’ and radio-frequency identification tags are potential objective methods that can distinguish walkers, but also require complex analysis, are costly, and still need their measurement properties corroborated. Subjective direct methods, such as questionnaires, diaries and direct observation, provide the richest information on walking, especially short-term diaries, such as trip records and time use records, and are particularly useful for assessing secondary purpose walking. A unifying measure for health research, surveillance and health promotion would strongly advance the understanding of the impact of walking on health.
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Health scientists and urban planners have long been interested in the influence that the built environment has on the physical activities in which we engage, the environmental…
Abstract
Health scientists and urban planners have long been interested in the influence that the built environment has on the physical activities in which we engage, the environmental hazards we face, the kinds of amenities we enjoy, and the resulting impacts on our health. However, it is widely recognized that the extent of this influence, and the specific cause-and-effect relationships that exist, are still relatively unclear. Recent reviews highlight the need for more individual-level data on daily activities (especially physical activity) over long periods of time linked spatially to real-world characteristics of the built environment in diverse settings, along with a wide range of personal mediating variables. While capturing objective data on the built environment has benefited from wide-scale availability of detailed land use and transport network databases, the same cannot be said of human activity. A more diverse history of data collection methods exists for such activity and continues to evolve owing to a variety of quickly emerging wearable sensor technologies. At present, no “gold standard” method has emerged for assessing physical activity type and intensity under the real-world conditions of the built environment; in fact, most methods have barely been tested outside of the laboratory, and those that have tend to experience significant drops in accuracy and reliability. This paper provides a review of these diverse methods and emerging technologies, including biochemical, self-report, direct observation, passive motion detection, and integrated approaches. Based on this review and current needs, an integrated three-tiered methodology is proposed, including: (1) passive location tracking (e.g., using global positioning systems); (2) passive motion/biometric tracking (e.g., using accelerometers); and (3) limited self-reporting (e.g., using prompted recall diaries). Key development issues are highlighted, including the need for proper validation and automated activity-detection algorithms. The paper ends with a look at some of the key lessons learned and new opportunities that have emerged at the crossroads of urban studies and health sciences.
We do have a vision for a world in which people can walk to shops, school, friends' homes, or transit stations; in which they can mingle with their neighbors and admire trees, plants, and waterways; in which the air and water are clean; and in which there are parks and play areas for children, gathering spots for teens and the elderly, and convenient work and recreation places for the rest of us. (Frumkin, Frank, & Jackson, 2004, p. xvii)
W.G. Heath and B.O. Heath
BEFORE a detailed consideration of internal stresses may be made, it is necessary to define external loadings which are possibly critical. This involves the consideration of…
Abstract
BEFORE a detailed consideration of internal stresses may be made, it is necessary to define external loadings which are possibly critical. This involves the consideration of manoeuvres throughout the altitude range of the aeroplane, to a severity fixed by aerodynamic or specification values of speed and normal acceleration.
IN Part I of this paper, the basic equations were established for the various modes of instability of flat sandwich panels subjected to lengthwise compression. Whilst these…
Abstract
IN Part I of this paper, the basic equations were established for the various modes of instability of flat sandwich panels subjected to lengthwise compression. Whilst these equations are valuable in determining the strength of a given panel they do not give a direct indication of the cross‐sectional dimensions of a panel required to carry a given load, especially if the panel is to be the optimum, i.e. of minimum weight.
An extensive bibliography exists on sandwich construction; it is felt, however, that few of the available papers are readily adaptable for use in aircraft design offices. This…
Abstract
An extensive bibliography exists on sandwich construction; it is felt, however, that few of the available papers are readily adaptable for use in aircraft design offices. This paper, whilst based on an existing theory, extends it to include panels with faces of unequal thicknesses and aeolotropic cores such as honeycomb. The various modes of failure are described, and comparisons are drawn between the equilibrium equations and those derived in the theory of solid plates. A very simple equation for the overall instability of a sandwich panel is obtained, based on the concept of ‘width reduction factors’ which make allowance for core flexibility and unequal face thicknesses. Methods are described for presenting these reduction factors' and other important parameters in the form of data sheets, of which examples are given. The panels which are discussed are assumed to be flat, and compressed by a load uniformly distributed across their ends. The edges, which are simply‐supported, are taken to be long in relation to the panel width.
W.G. HEATH, DipAe, CEng, E FIMech and FRAeS
The playwright identified seven roles for man to play as his life unfolded. In the realm of airworthiness, it is possible to identify six roles for structural testing as a project…
Abstract
The playwright identified seven roles for man to play as his life unfolded. In the realm of airworthiness, it is possible to identify six roles for structural testing as a project completes its life cycle. These roles coincide with the six phases of development of a project:
APPLICATION of the so‐called high energy liquid fuels and high energy liquid oxidizers to power plants based on the jet propulsion principle is receiving the increasing interest…
Abstract
APPLICATION of the so‐called high energy liquid fuels and high energy liquid oxidizers to power plants based on the jet propulsion principle is receiving the increasing interest and attention of rocket propellant chemists and power plant engineers universally. The aspect of substantially increased—as much as 50 per cent— energy per pound of propellant load or per cubic foot of propellant tankage over today's propellants has whetted scientific appetites and justified probing the field of high energy chemicals to determine, as logically and as practically as we can at the present time, the gains, problems, limitations and applications of these higher energy chemicals. The object of this paper is, in a general way, to discuss the subject of chemical rocket propellants in such a way that the following five questions will be, in part at least, answered or recalled to the minds of this audience for additional deliberation.
A Presentation of the Fail‐Safe Concept including the Design as it Applies to a Crack‐Free Life, Corrosion Prevention, Simplified Inspection and Repair, and Safety after Failure…
Abstract
A Presentation of the Fail‐Safe Concept including the Design as it Applies to a Crack‐Free Life, Corrosion Prevention, Simplified Inspection and Repair, and Safety after Failure. IN designing a new aircraft structure, the principal concern is to ensure that structural failure docs not occur during any stage—taxying, taking‐off, climbing, cruising, descending, landing—of any flight. This concern is not only for the safety and well‐being of the travelling public but also for the economics of airline operation, since the operator demands a long working life from his aircraft, and a good re‐sale value.
E.R. Major, BSc(Eng), FIMech. E, FSLAET FRAeS and FRSA
In my introductory article, “Airworthiness — A Systems Approach”, last March, I expressed the hope that eminent engineers from all the disciplines and activities on which “total…
Abstract
In my introductory article, “Airworthiness — A Systems Approach”, last March, I expressed the hope that eminent engineers from all the disciplines and activities on which “total airworthiness” (my phrase) depends, would be persuaded by Aircraft Engineering to contribute articles on their own specialisations.