2,195 research outputs found

    Effective Learning

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    Cultural political economy and urban heritage tourism

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    The paper explains a cultural political economy “framing” for interpreting heritage tourism in urban contexts. Key ideas behind this research perspective are explained and illustrated through discussion of past research studies of urban heritage tourism. It is underpinned by a relational view of the inter-connectedness of societal relations, and an emphasis on taking seriously both the cultural/semiotic and the economic/political in the co-constitution of urban heritage tourism’s social practices and features. A case study of heritage tourism in Nanjing, China considers cultural political economy’s relevance and value, including the distinctive research questions it raises. It reveals, for example, how economic relations in the built environment were related to tourist meaning-making and identities in the cultural/semiotic sphere

    Factors affecting human reliability in the chemical process industry

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    This research was concerned with identifying factors which may influence human reliability within chemical process plants - these factors are referred to as Performance Shaping Factors (PSFs). Following a period of familiarization within the industry, a number of case studies were undertaken covering a range of basic influencing factors. Plant records and site `lost time incident reports' were also used as supporting evidence for identifying and classifying PSFs. In parallel to the investigative research, the available literature appertaining to human reliability assessment and PSFs was considered in relation to the chemical process plan environment. As a direct result of this work, a PSF classification structure has been produced with an accompanying detailed listing. Phase two of the research considered the identification of important individual PSFs for specific situations. Based on the experience and data gained during phase one, it emerged that certain generic features of a task influenced PSF relevance. This led to the establishment of a finite set of generic task groups and response types. Similarly, certain PSFs influence some human errors more than others. The result was a set of error type key words, plus the identification and classification of error causes with their underlying error mechanisms. By linking all these aspects together, a comprehensive methodology has been forwarded as the basis of a computerized aid for system designers. To recapitulate, the major results of this research have been: One, the development of a comprehensive PSF listing specifically for the chemical process industries with a classification structure that facilitates future updates; and two, a model of identifying relevant SPFs and their order of priority. Future requirements are the evaluation of the PSF listing and the identification method. The latter must be considered both in terms of `useability' and its success as a design enhancer, in terms of an observable reduction in important human errors

    Development of the PsAQoL: a quality of life instrument specific to psoriatic arthritis

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    Background: Patient reported outcome measures used in studies of psoriatic arthritis (PsA) have been found to be inadequate for determining the impact of the disease from the patient’s perspective. Objective: To produce the PsAQoL, a PsA-specific quality of life (QoL) instrument, employing the needs based model of QoL that would be relevant and acceptable to respondents, valid, and reliable. Methods: Content was derived from qualitative interviews conducted with patients with PsA. Face and content validity were assessed by field test interviews with a new sample of patients with PsA. A postal survey was conducted to improve the scaling properties of the new measure. Finally, a test-retest postal survey was used to identify the final measure and to test its scaling properties, reliability, internal consistency, and validity. Results: Analysis of the qualitative interview transcripts identified a 51 item questionnaire. Field test interviews confirmed the acceptability and relevance of the measure. Analysis of data from the first postal survey (n = 94) reduced the questionnaire to 35 items. Rasch analysis of data from the test-retest survey (n = 286) identified a 20 item version of the PsAQoL with good item fit. This version had excellent internal consistency (a = 0.91), test-retest reliability (0.89), and validity. Conclusions: The PsAQoL is a valuable tool for assessing the impact of interventions for PsA in clinical studies and trials. It is well accepted by patients, taking about three minutes to complete, is easy to administer, and has excellent scaling and psychometric properties

    A More Accurate Generalized Gradient Approximation for Solids

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    We present a new nonempirical density functional generalized gradient approximation (GGA) that gives significant improvements for lattice constants, crystal structures, and metal surface energies over the most popular Perdew-Burke-Ernzerhof (PBE) GGA. The new functional is based on a diffuse radial cutoff for the exchange-hole in real space, and the analytic gradient expansion of the exchange energy for small gradients. There are no adjustable parameters, the constraining conditions of PBE are maintained, and the functional is easily implemented in existing codes.Comment: 5 pages, corrected the errors of the sublimation energy of Ih ic

    A new method for atmospheric detection of the CH3O2 radical

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    A new method for measurement of the methyl peroxy (CH3O2) radical has been developed using the conversion of CH3O2 into CH3O by excess NO with subsequent detection of CH3O by fluorescence assay by gas expansion (FAGE) with laser excitation at ca. 298 nm. The method can also directly detect CH3O, when no nitric oxide is added. Laboratory calibrations were performed to characterise the FAGE instrument sensitivity using the conventional radical source employed in OH calibration with conversion of a known concentration of OH into CH3O2 via reaction with CH4 in the presence of O2. Detection limits of 3.8 × 108 and 3.0 × 108 molecule cm−3 were determined for CH3O2 and CH3O respectively for a signal-to-noise ratio of 2 and 5 min averaging time. Averaging over 1 h reduces the detection limit for CH3O2 to 1.1 × 108 molecule cm−3, which is comparable to atmospheric concentrations. The kinetics of the second-order decay of CH3O2 via its self-reaction were observed in HIRAC (Highly Instrumented Reactor for Atmospheric Chemistry) at 295 K and 1 bar and used as an alternative method of calibration to obtain a calibration constant with overlapping error limits at the 1σ level with the result of the conventional method of calibration. The overall uncertainties of the two methods of calibrations are similar – 15 % for the kinetic method and 17 % for the conventional method – and are discussed in detail. The capability to quantitatively measure CH3O in chamber experiments is demonstrated via observation in HIRAC of CH3O formed as a product of the CH3O2 self-reaction

    Relationships between reading, tracing and writing skills in introductory programming

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    This study analyzed student responses to an examination, after the students had completed one semester of instruction in programming. The performance of students on code tracing tasks correlated with their performance on code writing tasks. A correlation was also found between performance on "explain in plain English" tasks and code writing. A stepwise regression, with performance on code writing as the dependent variable, was used to construct a path diagram. The diagram suggests the possibility of a hierarchy of programming related tasks. Knowledge of programming constructs forms the bottom of the hierarchy, with "explain in English", Parson's puzzles, and the tracing of iterative code forming one or more intermediate levels in the hierarchy. Copyright 2008 ACM

    The comparison of Friedel-Crafts alkylation and acylation as a means to synthesise alkyl xylenes

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    The aim of this project was to synthesise and characterise an alkyl xylene using both a Friedel-Crafts alkylation and a Friedel-Crafts acylation. The literature stated that whilst alkylation raised many issues with polyalkylation, transalkylation, dealkylation and rearrangement of the electrophile, acylation with subsequent reduction of the carbonyl provided a far less problematic route. Firstly, Friedel-Crafts alkylation of m-xylene was performed using t-butyl chloride. The product was purified by vacuum distillation and rotary evaporation. Analysis using IR, GC-FID, GC-MS and NMR allowed the conclusion of a 1,3,5-trisubstituted benzene product. Secondly, Friedel-Crafts acylation of m-xylene was performed using butyryl chloride. Analysis using IR, GC-FID, GC-MS and NMR allowed the conclusion of a 1,2,4-trisubstituted benzene product. The product of the alkylation reaction was unexpected due to the pre-existing methyl groups being ortho-para-directing. It was concluded that attack at the ortho and para positions allowed the intermediates to be stabilised, however due to steric hindrance the products would be of higher energy. It was therefore deemed that the acylation reaction product was kinetically controlled as the energy of the intermediates most influenced it; however, the alkylation reaction product was thermodynamically controlled. Literature stated this was likely to do with the reversibility of the alkylation reaction and the irreversibility of the acylation reaction. Grignard reactions were carried out on the synthesised acyl xylene using ethyl bromide and propyl bromide. With both reactions, a new peak at 3500 cm-1 occurred on the IR confirming synthesis of an alcohol. GC-MS analysis showed residual acyl xylene in the crude product as well as several peaks displaying the fragmentation patterns for the expected product. It was concluded that the GC-MS for the reaction using ethyl bromide displayed a greater number of peaks with similar fragmentation patterns due to the introduction of a chiral carbon. Further research suggested included the dehydration and hydrogenation of the Grignard products, the acylation and alkylation reactions carried out at varying temperatures and the acylation carried out with a branched acyl chloride
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