On the permutation behaviour of Dickson polynomials of the second kind

The known permutation behaviour of the Dickson polynomials of the second kind in characteristic 3 is expanded and simplified.

Stability of 2-D characteristic polynomials

This paper derives some new conditions for the bivariate characteristic polynomial of an uncertain matrix to be very strict Hurwitz. The uncertainties are assumed of the structured and unstructured type. By using the two-dimensional (2-D) inverse Laplace transform, the bounds on the uncertainties are derived which will ensure that the bivariate characteristic polynomial to be very strict Hurwitz. Two numerical examples are given to illustrate the results.

Fractional polynomials and model selection in generalized estimating equations analysis, with an application to a longitudinal epidemiologic study in Australia

In epidemiologic studies, researchers often need to establish a nonlinear exposure-response relation between a continuous risk factor and a health outcome. Furthermore, periodic interviews are often conducted to take repeated measurements from an individual. The authors proposed to use fractional polynomial models to jointly analyze the effects of 2 continuous risk factors on a health outcome. This method was applied to an analysis of the effects of age and cumulative fluoride exposure on forced vital capacity in a longitudinal study of lung function carried out among aluminum workers in Australia (1995-2003). Generalized estimating equations and the quasi-likelihood under the independence model criterion were used. The authors found that the second-degree fractional polynomial models for age and fluoride fitted the data best. The best model for age was robust across different models for fluoride, and the best model for fluoride was also robust. No evidence was found to suggest that the effects of smoking and cumulative fluoride exposure on change in forced vital capacity over time were significant. The trend 1 model, which included the unexposed persons in the analysis of trend in forced vital capacity over tertiles of fluoride exposure, did not fit the data well, and caution should be exercised when this method is used.

School day segmented physical activity patterns of high and low active children

Background

Variability exists in children's activity patterns due to the association with environmental, social, demographic, and inter-individual factors. This study described accelerometer assessed physical activity patterns of high and low active children during segmented school week days whilst controlling for potential correlates.
Methods

Two hundred and twenty-three children (mean age: 10.7 +/- 0.3 yrs, 55.6% girls, 18.9% overweight/obese) from 8 north-west England primary schools wore ActiGraph GT1M accelerometers for 7 consecutive days during autumn of 2009. ActiGraph counts were converted to minutes of moderate (MPA), vigorous (VPA) and moderate-to-vigorous (MVPA) physical activity. Children were classified as high active (HIGH) or low active (LOW) depending on the percentage of week days they accumulated at least 60 minutes of MVPA. Minutes spent in MPA and VPA were calculated for school time and non-school time and for five discrete school day segments (before-school, class time, recess, lunchtime, and after-school). Data were analysed using multi-level modelling.
Results

The HIGH group spent significantly longer in MPA and/or VPA before-school, during class time, lunchtime, and after-school (P < .05), independent of child and school level factors. The greatest differences occurred after-school (MPA = 5.5 minutes, VPA = 3.8 minutes, P < 0.001). MPA and VPA were also associated with gender, BMI z-score, number of enrolled children, playground area per student, and temperature, depending on the segment analysed. The additive effect of the segment differences was that the HIGH group accumulated 12.5 minutes per day more MVPA than the LOW group.
Conclusions

HIGH active children achieved significantly more MPA and VPA than LOW active during four of the five segments of the school day when analyses were adjusted for potential correlates. Physical activity promotion strategies targeting low active children during discretionary physical activity segments of the day, and particularly via structured after-school physical activity programs may be beneficial.

Electrostatically confined plasma in segmented hollow cathode geometries for surface engineering

A segmented hollow cathode (SHC) geometry was used for electrostatic confinement of plasma, and surface engineering treatments were conducted in this arrangement. The assessed processes included plasma nitriding, reactive deposition of sputtered material, and deposition of carbonaceous films by plasma-enhanced chemical vapor deposition with a bipolar pulsed-dc power supply on steel substrates. The treated specimens exhibited uniform surface morphology and deposition layers. Characterization techniques included optical microscopy, scanning electron microscopy with energy dispersive X-ray capability, and X-ray diffraction. The advantages and potential applications of the SHC arrangement are discussed in view of these results.

Leisure experiences in tourist attractions : exploring the motivations of local residents

This study was conducted to explore leisure motivations with regard to tourist attractions. A survey of a convenience sample of residents of Melbourne, Australia, was conducted. The sample was then segmented based on the likelihood of visiting a cross-section of Melbourne's tourist attractions in the next 6 months. Analysis using Unger and Kernan's (1983) Subjective Leisure Scale (SLS) was then undertaken to explore whether there were differences across the segments in terms of their leisure motivations. The results highlight that, within this context, intrinsic satisfaction, perceived freedom and arousal emerged as stronger underlying dimensions of motivations to visit tourist attractions, rather than mastery, spontaneity and involvement. This information provides insights for marketers of tourist attractions with regard to what residents are seeking when they visit local tourist attractions. The information can be used to develop more positive experiences at tourist attractions for this important sector of the market.

The determination of all syzygies for the dependent polynomial invariants of the Riemann Tensor. II. mixed invariants of Eeven degree in the Ricci Spinor

We continue our analysis of the polynomial invariants of the Riemann tensor in a four-dimensional Lorentzian space. We concentrate on the mixed invariants of even degree in the Ricci spinor Φ_ABȦḂ and show how, using constructive graph-theoretic methods, arbitrary scalar contractions between copies of the Weyl spinor ψ_ABCD, its conjugate ψ_ȦḂĊḊ and an even number of Ricci spinors can be expressed in terms of paired contractions between these spinors. This leads to an algorithm for the explicit expression of dependent invariants as polynomials of members of the complete set. Finally, we rigorously prove that the complete set as given by Sneddon [J. Math. Phys. 39, 1659-1679 (1998)] for this case is both complete and minimal.

Sports-events, tourism and destination marketing strategies: an Australian case study of Athens 2004 and its media telecast

The focus of this study was the media telecast of the Athens 2004 Summer Olympic Games. The study explored the efficacy of the Australian telecast in developing positive perceptions and attitudes of Greece as a tourist  destination and was origin-based—in that a survey was undertaken of a sample of Australian residents (n = 350). Participants were segmented based on their post-consumption perceptions of Greece. Four segments were identified and labelled—'extremely positive' (n = 75), 'highly positive' (n = 153), 'positive' (n = 83) and 'negative' (n = 29). Statistical differences were found between the segments based on whether attitudes towards Greece had improved as a result of their consumption of the media telecast of the Athens 2004 Olympic Games (Athens 2004). To gain insights into this phenomenon, open-ended responses provided by segment members were then analysed.

Across the sample, 38.7% of respondents indicated that their overall attitude towards Greece as tourist destination changed as a result of their consumption of the telecast of Athens 2004. Considering that the attitudes of participants in the current study improved, not as a result of first-hand experiences at the destination, but as a result of their vicarious experiences of the destination through consumption of a media telecast of a special event, the results provide insights to the efficacy of this particular telecast in developing positive attitudes with regard to Greece as a tourist destination. The results of this study could be used a benchmark for future event-related destination marketing strategies. Similarities and differences emerged between the segments with regard to the reasons as to why members of each of the clusters attitudes towards Greece as a tourist destination had improved as a result of their consumption of the telecast. While their responses appeared to be similar, the frequency in which the concepts emerged for each of the segments varied intensity. The key issues that emerged for the four clusters were the appearance of Greece; culture and history of Greece; capacity, or 'hostability', of Greece to stage the Athens 2004; and infrastructure in Greece.

Grid-based method for ranking images with multiple objects

One of the content-based image retrieval techniques is the shape-based technique, which allows users to ask for objects similar in shape to a query object. Sajjanhar and Lu proposed a method for shape representation and similarity measure called the grid-based method [1]. They have shown that the method is effective for the retrieval of segmented objects based on shape. In this paper, we describe a system which uses the grid-based method for retrieval of images with multiple objects. We perform experiments on the prototype system to compare the performance of the grid-based method with the Fourier descriptors method [2]. Preliminary results have been presented.

An empirical investigation of high relational orientation sport club members

Relationships between businesses, businesses and end customers, as well as between customers are an important area of practical and scientific interest. In the present era, largely due to digital technologies such as the database, public and private networks, and data collection and information distribution via TCP/IP (Transmission Control Protocol/Internet Protocol) interface tools such as the World Wide Web (Web), the interest in relationships and related aspects such as trust as it relates to Web interactivity continues. An important antecedent empirical study established that arts patrons (customers) of a New York theatre company could be segmented according to their relational orientation, and that this orientation mediated between component attitudes and future purchase intentions. The study reported in this paper employs Web-based data collection and postal data collection methods in an investigation of the mediation effects of these data collection methods used with the same population of a premier football club in Australia. While a future aim is to more closely compare the outcomes established in the arts study with those from a similarly constructed study in the sporting arena, the focus of this initial paper is the differences in response exhibited by online respondents relative to postal survey respondents. The paper reports findings which do not support those of the antecedent arts and entertainment study concerning the weakness of overall satisfaction on the purchase intentions of high relational orientation customers. The paper also reports findings which give confidence to users of online surveys that despite differences in demographic profiles of these respondents and postal survey respondents, there is a degree of similarity in the responses of the two groups on the measures used in this study. The paper also suggests the need for further research into these data collection effects as they relate to relationship marketing.