Consistent maximum likelihood estimation of a unimodal density using shape restrictions

It is well known that the unimodal maximum likelihood estimator of a density is consistent everywhere but at the mode. The authors review various ways to solve this problem and propose a new estimator that is concave over an interval containing the mode; this interval may be chosen by the user or through an algorithm. The authors show how to implement their solution and compare it to other approaches through simulations. They show that the new estimator is consistent everywhere and determine its rate of convergence in the Hellinger metric.     

Asthma Patients' Activities and Air Pollution: A Semiparametric Censored Regression Analysis

Asthma patients' health status may be especially sensitive to some types of air pollution, but the evidence on this is mixed. We explore the effects of ground-level ozone on asthma patient's activities, breaking apart the usual aggregated category of leisure into indoor and outdoor activities, and differentiating those by whether the activities were active or inactive. Applying the semiparametric censored estimation method we demonstrate that even though the period over which activities were observed was relatively low in ozone levels, there is a significant impact of ozone on a few activities. The (non-ozone) economic and demographic variables in the model play significant roles in explaining the allocation of time among seven activities, suggesting the suitability of the approach for other household decision-making contexts.     

The Development of Affect Specificity in Infants' Use of Emotion Cues

This study examined the emergence of affect specificity in infancy. In this study, infants received verbal and facial signals of 2 different, negatively valenced emotions (fear and sadness) as well as neutral affect via a television monitor to determine if they could make qualitative distinctions among emotions of the same valence. Twenty 12‐ to 14‐month‐olds and 20 16‐ to 18‐month‐olds were examined. Results suggested that younger infants showed no evidence of referential specificity, as they responded similarly to both the target and distracter toys, and showed no evidence of affect specificity, showing no difference in play between affect conditions. Older infants, in contrast, showed evidence both of referential and affect specificity. With respect to affect specificity, 16‐ to 18‐month‐olds touched the target toy less in the fear condition than in the sad condition and showed a larger proportion of negative facial expressions in the sad condition versus the fear condition. These findings suggest a developmental emergence after 15 months of age for affect specificity in relating emotional messages to objects.     

The Classed Body in the Sociological Imagination

Class theorists of embodiment in Sociology point to and illuminate both an over‐ and an under‐exposed body and experience that ultimately mark the bodies of the poor as ideologically, discursively and materially abject. In this essay, I map out theories of the bodies of the poor, including those of Marx, Engels, Elias, Bourdieu, Foucault, Donzelot and Adair. I suggest that an understanding of the ways in which the bodies of the poor are positioned as abject can facilitate a flexible and reflexive heuristic through which we can negotiate epistemic shifts between material and discursive categories, as well as providing us with a template through which we can come to understand even the most profoundly abject bodies, those of poor women in a welfare state, as potential sites of embodied agency and resistance, all central to the ethical and holistic study of sociology.     

The Impact of Maternal Characteristics and Sensitivity on the Concordance Between Maternal Reports and Laboratory Observations of Infant Negative Emotionality

The moderating role of maternal characteristics and maternal sensitivity on the concordance between maternal reports and laboratory observations of negative emotionality was examined. Participants were 90 primiparous mothers and their infants. Mothers completed questionnaires about remembered care from their own parents and their depressive symptoms prenatally, infant temperament (distress to novelty and distress to limitations), and depressive symptoms postnatally. Mothers and infants participated in a laboratory assessment of infant temperament (distress to novelty and limitations) and maternal sensitivity at 6 months postpartum. Several factors that moderate the degree of concordance between maternal reports and behavioral observations were identified, as predicted. Novelty concordance was higher when mothers reported having their emotional needs met in childhood and low prenatal depressive symptoms. Limitations concordance was higher when mothers were less sensitive during the observational tasks. Methodological and theoretical implications are discussed.     

The risky business of insurance pricing

The factors influencing insurance pricing decisions are assessed using the ISO product liability ratemaking files for 1980–1984. The mean loss level has a strong positive effect on manual rates and premium rates/exposure. Evidence on a variety of ambiguity measures is more mixed. As a broad generalization, risk ambiguity lowers manual rates, which may reflect exclusion of large loss outliers as being unrepresentative. Risk ambiguity tends to have a positive effect on actual pricing decisions for particular policies, especially bodily injury lines and the interactive risk-ambiguity model.