A simple Bayesian decision-theoretic design for dose-finding trials

A flexible and simple Bayesian decision-theoretic design for dose-finding trials is proposed in this paper. In order to reduce the computational burden, we adopt a working model with conjugate priors, which is flexible to fit all monotonic dose-toxicity curves and produces analytic posterior distributions. We also discuss how to use a proper utility function to reflect the interest of the trial. Patients are allocated based on not only the utility function but also the chosen dose selection rule. The most popular dose selection rule is the one-step-look-ahead (OSLA), which selects the best-so-far dose. A more complicated rule, such as the two-step-look-ahead, is theoretically more efficient than the OSLA only when the required distributional assumptions are met, which is, however, often not the case in practice. We carried out extensive simulation studies to evaluate these two dose selection rules and found that OSLA was often more efficient than two-step-look-ahead under the proposed Bayesian structure. Moreover, our simulation results show that the proposed Bayesian method's performance is superior to several popular Bayesian methods and that the negative impact of prior misspecification can be managed in the design stage.

A simple method for estimating growth parameters from multiple length-frequency data in presence of continuous recruitment

The extended recruitment season for short-lived species such as prawns biases the estimation of growth parameters from length-frequency data when conventional methods are used. We propose a simple method for overcoming this bias given a time series of length-frequency data. The difficulties arising from extended recruitment are eliminated by predicting the growth of the succeeding samples and the length increments of the recruits in previous samples. This method requires that some maximum size at recruitment can be specified. The advantages of this multiple length-frequency method are: it is simple to use; it requires only three parameters; no specific distributions need to be assumed; and the actual seasonal recruitment pattern does not have to be specified. We illustrate the new method with length-frequency data on the tiger prawn Penaeus esculentus from the north-western Gulf of Carpentaria, Australia.

Why the Constraints-Led Approach is not teaching games for understanding: A clarification

Background There is some apparent confusion regarding similarities and differences between two popular physical education (PE) pedagogical frameworks, that is, the Constraints-Led Approach (CLA) and Teaching Games for Understanding (TGfU). Purpose Our aim in this commentary is to detail important theoretical and pedagogical concepts that distinguish these approaches, as well as to recognise where commonalities exist. Findings In particular, we note that TGfU had its roots in the 1960s in the absence of a substantial theoretical framework, although several attempts to retrospectively scaffold theories around TGfU have subsequently emerged in the literature. TGfU is a learner-centred approach to PE in which teachers are encouraged to design modified games to develop the learner's understanding of tactical concepts. In contrast, the CLA has arisen more recently from the umbrella of Nonlinear Pedagogy (NLP), emerging from the empirically rich theoretical framework of ecological dynamics. The CLA adopts a ‘learner–environment’ scale of analysis in which practitioners are encouraged to identify and modify interacting constraints (of task, environment and learner) to facilitate the coupling of each learner's perceptual and action systems during learning. The CLA is a broader framework which has been adapted for the design of (re)learning environments in PE, sport and movement therapy. Other key distinctions between the approaches include: the overall goals; the way in which the learner and the learning process are modelled; the use of questioning as a pedagogical tool; the focus on individual differences vs. generic concepts; and how progressions and skill interjections are planned and implemented. Conclusions Despite such distinctions, the two approaches are somewhat harmonious and key similarities include: their holistic perspective of the learner; the proposed role of the teacher and the design characteristics of learning tasks in each. Both TGfU and the CLA have a powerful central focus on the nature of learning activities undertaken by each individual learner. This clarification of TGFU and the CLA is intended to act as a catalyst for more empirical work into the complementarity of these juxtaposed pedagogical approaches to learning design.

A simple and fast two-locus quality control test to detect false positives due to batch effects in genome-wide association studies

The impact of erroneous genotypes having passed standard quality control (QC) can be severe in genome-wide association studies, genotype imputation, and estimation of heritability and prediction of genetic risk based on single nucleotide polymorphisms (SNP). To detect such genotyping errors, a simple two-locus QC method, based on the difference in test statistic of association between single SNPs and pairs of SNPs, was developed and applied. The proposed approach could detect many problematic SNPs with statistical significance even when standard single SNP QC analyses fail to detect them in real data. Depending on the data set used, the number of erroneous SNPs that were not filtered out by standard single SNP QC but detected by the proposed approach varied from a few hundred to thousands. Using simulated data, it was shown that the proposed method was powerful and performed better than other tested existing methods. The power of the proposed approach to detect erroneous genotypes was approximately 80% for a 3% error rate per SNP. This novel QC approach is easy to implement and computationally efficient, and can lead to a better quality of genotypes for subsequent genotype-phenotype investigations.

A simple correction for multiple testing for single-nucleotide polymorphisms in linkage disequilibrium with each other

In this report, we describe a simple correction for multiple testing of single-nucleotide polymorphisms (SNPs) in linkage disequilibrium (LD) with each other, on the basis of the spectral decomposition (SpD) of matrices of pairwise LD between SNPs. This method provides a useful alternative to more computationally intensive permutation tests. Additionally, output from SNPSpD includes eigenvalues, principal-component coefficients, and factor "loadings" after varimax rotation, enabling the selection of a subset of SNPs that optimize the information in a genomic region.

Balancing entertainment and behaviour value: M-games as a social marketing agent of change

In a marketplace where millions of dollars are spent on the design of mobile games (m-games), social marketers are now using this technology as a tool for behaviour change. Despite high expenditure by governments and non-profits on social marketing m-games, little is known about their effectiveness in terms of creating value. Value creation has been demonstrated to have an important impact on satisfaction and behaviour. This paper reports the results of a qualitative study involving four focus groups with 23 participants to reveal two categories of experiential value, entertainment and behaviour. Additionally, it was discovered that entertainment could be characterised by amusement and social value dimensions. Whereas, behaviour could be made up of information, simulation and distraction value dimensions. The categories of value, as well as the dimensions of information, simulation and distraction are entirely new to the social marketing literature and thus represents a unique contribution to social marketing.

Social marketers playing to win? Experiential value creation in social marketing mobile games

The rapid change of technological trends in the marketplace has increased the difficulty for social marketers to reach consumers using traditional marketing channels (Della et al., 2008). Traditionally, social marketing interventions have typically used more conventional supporting products and services such as water counters for water conservation or condoms for sex safety. However, recently social marketers are witnessing the diminishing effectiveness of more traditional social products and services in encouraging the uptake and maintenance of behaviour. In light of the technological trends in the marketplace and diminishing effect of previous social products and services (Lefebvre, 2009), social marketers have been encouraged to look to alternate means of delivering valuable offerings...

Disguising the performance of M-games in social marketing

Despite the explosion of mobile games (m-games) and the uptake of games as a social marketing tool for behaviour change, little is known about which game attributes (design factors within a game) are preferred by consumers for social marketing m-games. This research reports the findings of four focus groups (n=23) to propose three new categories of game attributes along with seven preferred game attributes for social marketing m-games. These results provide a unique contribution to social marketing theory given the goal of a social marketing m-game game is both entertainment and behaviour change. Further, the findings suggest strategies for practitioners seeking to develop, design and build social marketing m-games.

Structuring time and questioning to achieve tactical awareness in games lessons

Background: A paradigm shift in educational policy to create problem solvers and critical thinkers produced the games concept approach (GCA) in Singapore's Revised Syllabus for Physical Education (1999). A pilot study (2001) conducted on 11 primary school student teachers (STs) using this approach identified time management and questioning as two of the major challenges faced by novice teachers. Purpose: To examine the GCA from three perspectives: structure—lesson form in terms of teacher-time and pupil-time; product—how STs used those time fractions; and process—the nature of their questioning (type, timing, and target). Participants and setting: Forty-nine STs from three different PETE cohorts (two-year diploma, four-year degree, two-year post-graduate diploma) volunteered to participate in the study conducted during the penultimate week of their final practicum in public primary and secondary schools. Intervention: Based on the findings of the pilot study, PETE increased the emphasis on GCA content specific knowledge and pedagogical procedures. To further support STs learning to actualise the GCA, authentic micro-teaching experiences that were closely monitored by faculty were provided in schools nearby. Research design: This is a descriptive study of time-management and questioning strategies implemented by STs on practicum. Each lesson was segmented into a number of sub-categories of teacher-time (organisation, demonstration and closure) and pupil-time (practice time and game time). Questions were categorised as knowledge, technical, tactical or affective. Data collection: Each ST was video-taped teaching a GCA lesson towards the end of their final practicum. The STs individually determined the timing of the data collection and the lesson to be observed. Data analysis: Each lesson was segmented into a number of sub-categories of both teacher- and pupil-time. Duration recording using Noldus software (Observer 4.0) segmented the time management of different lesson components. Questioning was coded in terms of type, timing and target. Separate MANOVAs were used to measure the difference between programmes and levels (primary and secondary) in relation to time-management procedures and questioning strategies. Findings: No differences emerged between the programmes or levels in their time-management or questioning strategies. Using the GCA, STs generated more pupil time (53%) than teacher time (47%). STs at the primary level provided more technical practice, and those in secondary schools more small-sided game play. Most questions (58%) were asked during play or practice but were substantially low-order involving knowledge or recall (76%) and only 6.7% were open-ended or divergent and capable of developing tactical awareness. Conclusions: Although STs are delivering more pupil time (practice and game) than teacher-time, the lesson structure requires further fine-tuning to extend the practice task beyond technical drills. Many questions are being asked to generate knowledge about games but lack sufficient quality to enhance critical thinking and tactical awareness, as the GCA intends.

Operationalising and measuring flow in video games

This paper explores the obstacles associated with designing video game levels for the purpose of objectively measuring flow. We sought to create three video game levels capable of inducing a flow state, an overload state (low-flow), and a boredom state (low-flow). A pilot study, in which participants self-reported levels of flow after playing all three game levels, was undertaken. Unexpected results point to the challenges of operationalising flow in video game research, obstacles in experimental design for invoking flow and low-flow, concerns about flow as a construct for measuring video game enjoyment, the applicability of self-report flow scales, and the experience of flow in video game play despite substantial challenge-skill differences.

Ductile deformation of single inclusions in simple shear with a finite-strain hyperelastoviscoplastic rheology

We examine the 2D plane-­strain deformation of initially round, matrix-­bonded, deformable single inclusions in isothermal simple shear using a recently introduced hyperelastoviscoplastic rheology. The broad parameter space spanned by the wide range of effective viscosities, yield stresses, relaxation times, and strain rates encountered in the ductile lithosphere is explored systematically for weak and strong inclusions, the effective viscosity of which varies with respect to the matrix. Most inclusion studies to date focused on elastic or purely viscous rheologies. Comparing our results with linear-­viscous inclusions in a linear-­viscous matrix, we observe significantly different shape evolution of weak and strong inclusions over most of the relevant parameter space. The evolution of inclusion inclination relative to the shear plane is more strongly affected by elastic and plastic contributions to rheology in the case of strong inclusions. In addition, we found that strong inclusions deform in the transient viscoelastic stress regime at high Weissenberg numbers (≥0.01) up to bulk shear strains larger than 3. Studies using the shapes of deformed objects for finite-­strain analysis or viscosity-­ratio estimation should establish carefully which rheology and loading conditions reflect material and deformation properties. We suggest that relatively strong, deformable clasts in shear zones retain stored energy up to fairly high shear strains. Hence, purely viscous models of clast deformation may overlook an important contribution to the energy budget, which may drive dissipation processes within and around natural inclusions.

Is it the economy, stupid? The role of social versus economic factors in people’s support for hosting the Olympic Games: Evidence from 12 democratic countries

Public referenda have gained momentum as a democratic tool to legitimize public mega projects such as hosting the Olympic Games. Interest groups in favour of hosting the Olympics therefore try to influence voters through public campaigns that primarily focus on economic benefits. However, recent studies find no or hardly any economic impact of hosting the Olympics, instead providing evidence for a positive social impact. This raises the question whether citizens consider economic or social factors when deciding on hosting the Olympics. Based on representative survey data from 12 countries, our results suggest that economic factors can influence voting behaviour, although the influence of social factors is stronger.