NONLINEAR TUBE-FITTING FOR THE ANALYSIS OF ANATOMICAL AND FUNCTIONAL STRUCTURES

We are concerned with the estimation of the exterior surface and interior summaries of tube-shaped anatomical structures. This interest is motivated by two distinct scientific goals, one dealing with the distribution of HIV microbicide in the colon and the other with measuring degradation in white-matter tracts in the brain. Our problem is posed as the estimation of the support of a distribution in three dimensions from a sample from that distribution, possibly measured with error. We propose a novel tube-fitting algorithm to construct such estimators. Further, we conduct a simulation study to aid in the choice of a key parameter of the algorithm, and we test our algorithm with validation study tailored to the motivating data sets. Finally, we apply the tube-fitting algorithm to a colon image produced by single photon emission computed tomography (SPECT) and to a white-matter tract image produced using diffusion tensor imaging (DTI).     

An Integration Project in Civics and English

The intent of this article is to examine the significance of Carter G. Woodson to the historical development of the fields of curriculum and social studies, particularly as they relate to the evolution of the modern multicultural movement. The authors focus on Woodson's contributions through his curriculum and his pedagogical efforts in establishing a more rigorous and historically accurate social studies framework through his community education initiatives, the Negro History Bulletin, and his textbooks. They conclude the article with a discussion of how Woodson's efforts can have direct implications for social studies educators.     

‘Sit in the corner and don’t eat the crayons’: postgraduates with dyslexia and the dominant ‘lexic’ discourse

The lack of cultural diversity in higher education is recognised by policy objectives and a current focus on the development of widening participation for a range of students, including those with disabilities. Amongst this group are those with dyslexia who might previously have been disenfranchised from formal education and under‐represented within it. This paper explores the personal narratives and learner histories of six postgraduates and academics with dyslexia from their earliest memories of learning to their present experiences. It examines how literacy, as a dominant form of discourse, has defined concepts of academic ability resulting in the early exclusion of these learners from formal education. It is argued that this dominant discourse can be challenged by non‐authorised, informal learning resulting in stories of resistance.     

Predicting treatment efficacy via quantitative magnetic resonance imaging: a Bayesian joint model

The prognosis for patients with high grade gliomas is poor, with a median survival of 1 year. Treatment efficacy assessment is typically unavailable until 5-6 months post diagnosis. Investigators hypothesize that quantitative magnetic resonance imaging can assess treatment efficacy 3 weeks after therapy starts, thereby allowing salvage treatments to begin earlier. The purpose of this work is to build a predictive model of treatment efficacy by using quantitative magnetic resonance imaging data and to assess its performance. The outcome is 1-year survival status. We propose a joint, two-stage Bayesian model. In stage I, we smooth the image data with a multivariate spatiotemporal pairwise difference prior. We propose four summary statistics that are functionals of posterior parameters from the first-stage model. In stage II, these statistics enter a generalized non-linear model as predictors of survival status. We use the probit link and a multivariate adaptive regression spline basis. Gibbs sampling and reversible jump Markov chain Monte Carlo methods are applied iteratively between the two stages to estimate the posterior distribution. Through both simulation studies and model performance comparisons we find that we can achieve higher overall correct classification rates by accounting for the spatiotemporal correlation in the images and by allowing for a more complex and flexible decision boundary provided by the generalized non-linear model.     

Small-Sample Properties of GMM-Based Wald Tests

This article assesses the small-sample properties of generalized-method-of-moments-based Wald statistics by using (a) a vector white-noise process and (b) an equilibrium business-cycle model as the data-generating mechanisms. In many cases, the small-sample size of the Wald tests exceeds its asymptotic size and increases sharply with the number of hypotheses being jointly tested. We argue that this is mostly due to difficulty in estimating the spectral-density matrix of the residuals. Estimators of this matrix that impose restrictions implied by the model or the null hypothesis substantially improve the properties of the Wald statistics.     

Issues in understanding quality volunteering in human services

Organisations providing human services are under increasing pressure to demonstrate quality from a range of sources such as new legislation and new requirements for government funding. Four dimensions for examining quality, derived from program evaluation theory, illustrated some of the contradictions surrounding these expectations. The research used a qualitative and grounded approach to exploring clients', volunteers' and coordinators' notions of quality service. The clients' and volunteers' perceptions of quality were highly experiential, related to the specific context and focussed on strong trusting personal relationships. Clients were also very conscious of their lack of power. Coordinators used a combination of approaches to try to satisfy the demands of clients, volunteers and bureaucracy.     

Groups and individuals: conformity and diversity in the performance of gendered identities

The nature and role of social groups is a central tension in sociology. On the one hand, the idea of a group enables sociologists to locate and describe individuals in terms of characteristics that are shared with others. On the other, emphasizing the fluidity of categories such as gender or ethnicity undermines their legitimacy as ways of classifying people and, by extension, the legitimacy of categorization as a goal of sociological research. In this paper, we use a new research method known as the Imitation Game to defend the social group as a sociological concept. We show that, despite the diversity of practices that may be consistent with self‐identified membership of a group, there are also shared normative expectations – typically narrower in nature than the diversity displayed by individual group members – that shape the ways in which category membership can be discussed with, and performed to, others. Two claims follow from this. First, the Imitation Game provides a way of simultaneously revealing both the diversity and ‘groupishness’ of social groups. Second, that the social group, in the quasi‐Durkheimian sense of something that transcends the individual, remains an important concept for sociology.     

Overwhelming Casualties: Medical Ethics in a Time of Terror

Codes of ethics and ethics guidelines define standards of professional conduct, and ways to prioritize or balance ethical principles when these appear to be in conflict. In 1991 an international and interdisciplinary group of scholars met at the University of Toronto to discuss these problems in a Workshop on Ethical Considerations in Scholarship and Science. A document, “The Toronto Resolution”; (TTR), was developed, providing twelve principles for incorporation into scientific and scholarly codes, with the object of ensuring that professionals in science recognize the potential consequences of their work in the broader social context. To examine the extent to which existing codes are consonant with The Toronto Resolution's 12 principles, a content analysis was conducted on the codes of 21 Ontario‐based scientific and scholarly organizations. Criteria used in the content analysis were standardized and determined to be reliable. Only a weak correspondence was found between the contents of the codes of the scientific and scholarly organizations surveyed here and the principles set out in TTR. In particular, guidelines on specific social issues such as environmental effects or conflict resolution are scarcely mentioned at all. This study encourages consideration of The Toronto Resolution by the ethics committees of scientific and scholarly associations, as codes are revised or as new interpretations of principles in the codes evolve.     

Effects of sex guilt and premarital sexual permissiveness on role‐played sex education and moral attitudes

Anne Fausto‐Sterling's suggestion that the prevalence of intersex might be as high as 1.7% has attracted wide attention in both the scholarly press and the popular media. Many reviewers are not aware that this figure includes conditions which most clinicians do not recognize as intersex, such as Klinefelter syndrome, Turner syndrome, and late‐onset adrenal hyper‐plasia. If the term intersex is to retain any meaning, the term should be restricted to those conditions in which chromosomal sex is inconsistent with phenotypic sex, or in which the phenotype is not classifiable as either male or female. Applying this more precise definition, the true prevalence of intersex is seen to be about 0.018%, almost 100 times lower than Fausto‐Sterling's estimate of 1.7%.