Bayesian object matching

A Bayesian approach to object matching is presented. An object and a scene are each represented by features, such as critical points, line segments and surface patches, constrained by unary properties and contextual relations. The matching is presented as a labeling problem, where each feature in the scene is assigned (associated with) a feature of the known model objects. The prior distribution of a scene's labeling is modeled as a Markov random field, which encodes the between-object constraints. The conditional distribution of the observed features labeled is assumed to be Gaussian, which encodes the within-object constraints. An optimal solution is defined as a maximum a posteriori estimate. Relationships with previous work are discussed. Experimental results are shown.     

Assessing Speech Discrimination in Individual Infants

Assessing speech discrimination skills in individual infants from clinical populations (e.g., infants with hearing impairment) has important diagnostic value. However, most infant speech discrimination paradigms have been designed to test group effects rather than individual differences. Other procedures suffer from high attrition rates. In this study, we developed 4 variants of the Visual Habituation Procedure (VHP) and assessed their robustness in detecting individual 9‐month‐old infants' ability to discriminate highly contrastive nonwords. In each variant, infants were first habituated to audiovisual repetitions of a nonword (seepug) before entering the test phase. The test phase in Experiment 1 (extended variant) consisted of 7 old trials (seepug) and 7 novel trials (boodup) in alternating order. In Experiment 2, we tested 3 novel variants that incorporated methodological features of other behavioral paradigms. For the oddity variant, only 4 novel trials and 10 old trials were used. The stimulus alternation variant was identical to the extended variant except that novel trials were replaced with “alternating” trials—trials that contained repetitions of both the old and novel nonwords. The hybrid variant incorporated elements from both the oddity and the stimulus alternation variants. The hybrid variant proved to be the most successful in detecting statistically significant discrimination in individual infants (8 out of 10), suggesting that both the oddity and the stimulus alternation features contribute to providing a robust methodology for assessing discrimination in individual infants. In Experiment 3, we found that the hybrid variant had good test‐retest reliability. Implications of these results for future infant speech perception work with clinical populations are discussed.     

Transcending the fissure in risk theory: critical realism and child welfare

Within risk theory a key fissure has emerged. On the one hand, objectivist theories continue to treat risk as a measurable entity, while on the other, subjectivist accounts approach risk as a socially constructed phenomenon. Arguably, we need to transcend this false opposition and harmonize important insights from both approaches. Building on an earlier paper in this journal, the author tries to achieve this synthesis by applying Bhaskar's critical realist perspective to this contested area. The reconciliation of objectivism and subjectivism within critical realism, it is argued, redirects our attention to the deep‐seated causes of harm or the underlying mechanisms that, when activated, give rise to situations involving risk. The paper concludes by reviewing the implications of these ideas for child and family social work. It is here that connections are made with attachment theory and the recent interest in childhood resilience.     

ANALYZING NARRATIVES OF EXPERTISE:

Recent work in the sociology of professions highlights the central importance of abstract discourse in professionalization processes. Drawing on the work of Kenneth Burke, I argue that broadening the focus of analysis from "abstract discourse" to "narratives of expertise" will provide the ability to (1) more clearly analyze the social conditions that are conducive to the efficacy of abstraction as a basis for a claim of expertise and (2) theorize and empirically examine the formation and maintenance of a collective professional identity. To assist in the reformulation of professionalization studies around narratives of expertise, I develop a modified extension of Burke's five key terms of dramatism (act, agent, scene, agency, and purpose). Burke's pentadic scheme enables researchers to show how narratives of expertise ground jurisdictional claims and the constitution of professional identity in one of the elements of pentad. I illustrate the empirical power of the pertadic scheme through an examination of claims of psychotherapeutic expertise, particularly claims of marital and familial expertise.     

Development of Pre-Word-Learning Skills in Infants with Cochlear Implants

Families of infants who are congenitally deaf now have the option of cochlear implantation at a very young age. In order to assess the effectiveness of early cochlear implantation, however, new behavioral procedures are needed to measure speech perception and language skills during infancy. One important component of language development is word learning-a complex skill that involves learning arbitrary relations between words and their referents. A precursor to word learning is the ability to perceive and encode intersensory relations between co-occurring auditory and visual events. Recent studies in infants with normal hearing have shown that intersensory redundancies, such as temporal synchrony, can facilitate the ability to learn arbitrary pairings between speech sounds and objects (Gogate & Bahrick, 1998). To investigate the early stages of learning arbitrary pairings of sounds and objects after cochlear implantation, we used the Preferential Looking Paradigm (PLP) to assess infants' ability to associate speech sounds to objects that moved in temporal synchrony with the onset and offsets of the signals. Children with normal hearing ranging in age from 6, 9, 18, and 30 months served as controls and demonstrated the ability to learn arbitrary pairings between temporally synchronous speech sounds and dynamic visual events. Infants who received their cochlear implants (CIs) at earlier ages (7-15 months of age) performed similarly to the infants with normal hearing after about 2-6 months of CI experience. In contrast, infants who received their implants at later ages (16-25 months of age) did not demonstrate learning of the associations within the context of this experiment. Possible implications of these findings are discussed.     

Father-Absence and the Development of Sex Role

The lack of data-based research on the effects of father absence provided the major focus of the study. Comparisons are made between sex-role development in father-absent boys, male singletons and males in the four sibling-status positions in two-child families. On three measures of sex-role development, differences between the groups are shown. The father-absent groups are shown to rank poorly in comparison with their peers. Although no firm explanations are adduced for this developmental disadvantage, the possibilities of compensatory masculinity and critical periods in sex-role establishment are raised. The need for provision of adequate male sex role models for boys during the psychosexually formative years and some implications for future research are discussed.     

Who supports physicians in malpractice cases?

Malpractice suits have a devastating emotional impact on physicians. Learn about a unique service offered by the HealthTexas Provider Network to help doctors deal with the shock and sadness.     

An Improved Condensation Procedure in Discrete Probability Distribution Calculations

A "vertical" condensation scheme for discrete probability distribution (DPD) calculations is presented as an alternative to the earlier "horizontal" scheme, an example of which was presented recently by Kurth and Cox. When applied to DPDs over a space of curves, the vertical condensation results in a "regularization" of the "spaghetti" of curves that results from combination operations on such DPDs.