7,741 research outputs found

    Precedence relationship representations of mechanical assembly sequences

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    Two types of precedence relationship representations for mechanical assembly sequences are presented: precedence relationships between the establishment of one connection between two parts and the establishment of another connection, and precedence relationships between the establishment of one connection and states of the assembly process. Precedence relationship representations have the advantage of being very compact. The problem with these representations was how to guarantee their correctness and completeness. Two theorems are presented each of which leads to the generation of one type of precedence relationship representation guaranteeing its correctness and completeness for a class of assemblies

    Development of the children's eating behaviour questionnaire

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    Individual differences in several aspects of eating style have been implicated in the development of weight problems in children and adults, but there are presently no reliable and valid scales that assess a range of dimensions of eating style. This paper describes the development and preliminary validation of a parent-rated instrument to assess eight dimensions of eating style in children; the Children's Eating Behaviour Questionnaire (CEBQ). Constructs for inclusion were derived both from the existing literature on eating behaviour in children and adults, and from interviews with parents. They included reponsiveness to food, enjoyment of food, satiety responsiveness, slowness in eating, fussiness, emotional overeating, emotional undereating, and desire for drinks. A. large pool of items covering each of these: constructs was developed. The number of items was then successively culled through analysis of responses from three samples of families of young children (N = 131; N = 187, N = 218), to produce a 35-item instrument with eight scales which were internally valid and had good test-retest reliability. Investigation of variations by gender and age revealed only minimal gender differences in any aspect of eating style. Satiety responsiveness and slowness in eating diminished from age 3 to 8. Enjoyment of food and food responsiveness increased over this age range. The CEBQ should provide a useful measure of eating style for research into the early precursors of obesity or eating disorders. This is especially important in relation to the growing evidence for the heritability of obesity, where good measurement of the associated behavioural phenotype will be crucial in investigating the contribution of inherited variations in eating behaviour to the process of weight gain

    The effect of flight line spacing on radioactivity inventory and spatial feature characteristics of airborne gamma-ray spectrometry data

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    Airborne Gamma Spectrometry (AGS) is well suited to the mapping of radioactivity in the environment. Flight parameters (e.g. speed and line spacing) directly affect the rate of area coverage, cost, and data quality of any survey. The influences of line spacing have been investigated for data from inter‐tidal, coastal and upland environments with a range of <sup>137</sup>Cs activity concentrations and depositional histories. Estimates of the integrated <sup>137</sup>Cs activity (‘inventory’) within specified areas and the shapes of depositional features were calculated for subsets of the data at different line spacings. Features with dimensions greater than the line spacing show variations in inventory and area of less than 3%, and features with dimensions less than the line spacing show larger variations and a decreased probability of detection. The choice of line spacing for a task is dependent on the dimensions of the features of interest and required edge definition. Options for line spacing for different tasks are suggested. It is noted that for regional mapping, even 5–10 km line spacing can produce useful data

    Modeling the Distribution of Lightning Strike Distances Outside a Preexisting Lightning Area

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    Air Force Instruction 91-203 (AFI 91-203) directs that a lightning warning be issued when lightning is occurring or imminent within a 5 nautical mile (NM) radius of a predetermined location or activity. The 45 Weather Squadron (WS), located on the central eastern coast of Florida, balances the safety of personnel and space launch vehicles with lost productivity of taking shelter from lightning. The primary objective of this study investigates if this 5 NM safety radius can be reduced while maintaining a desired level of safety. The research uses processed Lightning Detection and Ranging (LDAR) data to map the movement of preexisting lightning storms using ellipses, which are updated with every lightning ash. A systematic recording ensues for the distance from the ellipse boundary of each ash occurring outside the ellipse. All of those exterior ash distances are then used to find the best-fit distribution from which the stand-off distance for the desired level of safety can be calculated. The distances from the edge of the ellipse are fit to a Weibull distribution and a new warning distance of 4 NM is selected as the most appropriate distance to balance safety and increase productivity. The 4 NM radius is tested with a resulting failure rate of .277%, with a savings of 22.5 8-hour man days a year for the months of May through September

    The VOICE Study: Valuing Opinions, Individual Communication and Experience: Building the evidence base for undertaking patient-centred family meetings in palliative care - a mixed methods study

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    Background: Despite family meetings being widely used to facilitate discussion among patients, families, and clinicians in palliative care, there is limited evidence to support their use. This study aims to assess the acceptability and feasibility of Patient-Centred Family Meetings in specialist inpatient palliative care units for patients, families, and clinicians and determine the suitability and feasibility of validated outcome measures from the patient and family perspectives. Methods: The study is a mixed-methods quasi-experimental design with pre-planned Patient-Centred Family Meetings at the intervention site. The patient will set the meeting agenda a priori allowing an opportunity for their issues to be prioritised and addressed. At the control site, usual care will be maintained which may include a family meeting. Each site will recruit 20 dyads comprising a terminally ill inpatient and their nominated family member. Pre- and post-test administration of the Distress Thermometer, QUAL-EC, QUAL-E, and Patient Health Questionnaire-4 will assess patient and family distress and satisfaction with quality of life. Patient, family, and clinician interviews post-meeting will provide insights into the meeting feasibility and outcome measures. Recruitment percentages and outcome measure completion will also inform feasibility. Descriptive statistics will summarise pre- and post-meeting data generated by the outcome measures. SPSS will analyse the quantitative data. Grounded theory will guide the qualitative data analysis. Discussion: This study will determine whether planned Patient-Centred Family Meetings are feasible and acceptable and assess the suitability and feasibility of the outcome measures. It will inform a future phase III randomised controlled trial. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12616001083482 on 11 August 201

    Many-body interactions in a quantum wire in the integer quantum Hall regime: suppression of exchange-enhanced g factor

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    The collapse of Hall gaps in the integer quantum Hall liquid in a quantum wire is investigated. Motivated by recent experiment [Pallecchi et al. PRB 65, 125303 (2002)] previous approaches are extended to treat confinement effects and the exchanged enhanced g-factor in quantum wires. Two scenarios for the collapse of the ν=1\nu =1 state are discussed. In the first one the ν=1\nu =1 state becomes unstable at Bcr(1)B_{cr}^{(1)}, due to the exchange interaction and correlation effects, coming from the edge-states screening. In the second scenario, a transition to the ν=2\nu =2 state occurs at Bcr(2)B_{cr}^{(2)}, with a smaller effective channel width, caused by the redistribution of the charge density. This effect turns the Hartree interaction essential in calculating the total energy and changes Bcr(2)B_{cr}^{(2)} drastically. In both scenarios, the exchange enhanced g-factor is suppressed for magnetic fields lower than BcrB_{cr}. Phase diagrams for the Hall gap collapse are determined. The critical fields, activation energy, and optical gg-factor obtained are compared with experiments. Within the accuracy of the available data, the first scenario is most probable to be realized.Comment: 11 pages, 10 figure
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