Global Convergence of the EM Algorithm for Unconstrained Latent Variable Models with Categorical Indicators

Convergence of the expectation-maximization (EM) algorithm to a global optimum of the marginal log likelihood function for unconstrained latent variable models with categorical indicators is presented. The sufficient conditions under which global convergence of the EM algorithm is attainable are provided in an information-theoretic context by interpreting the EM algorithm as alternating minimization of the Kullback–Leibler divergence between two convex sets. It is shown that these conditions are satisfied by an unconstrained latent class model, yielding an optimal bound against which more highly constrained models may be compared.     

Dichotic listening,executive functions and grey matter cortical volume in patients with schizophrenia and healthy controls

Schizophrenia is characterized by cognitive impairment, especially in relation to executive functions. Brain structural abnormalities are also often seen in schizophrenia although little is known of the relationship between cognitive impairment and structural brain changes. Our aim was therefore to investigate this relationship further using MRI and a dichotic listening (DL) task with simple speech sounds and with instructions to focus attention and report only from the left or right ear stimulus. When instructed to focus attention on the left ear syllable a cognitive conflict is induced requiring the allocation of executive resources to be resolved. Grey matter (GM) volume was measured with MRI from four volumes of interests (VOIs), left and right frontal and temporal cortex, respectively, and correlated with DL performance. The results showed significant differences between the groups in their ability to focus attention on and report the left ear stimulus, which was accompanied by reduced GM volume in the left frontal and right temporal lobe VOIs. There was also a significant positive correlation between left frontal GM volume and performance on the DL task, for the groups combined. The results did not support a conclusion that an impairment in cognitive function in schizophrenia was driven by an corresponding impairment in brain structure, since there were no significant correlations when the groups were analyzed separately. It is however concluded that patients with schizophrenia are impaired in executive functions and that they also show reduced GM volumes in left frontal and right temporal lobe areas, compared to healthy controls.     

Sense in Competing Narratives of Secularization: Charles Taylor and Jean-Luc Nancy

In this article, using the recent work by Charles Taylor in A Secular Age as my point of departure, I will argue that Jean-Luc Nancy enables us to think past the competing binary of atheistic and religious experience and allows us to surpass the present narratives of secularism. In A Secular Age, Taylor himself seeks a middle ground between atheism and religion, arguing that it is possible to open ourselves to the cross-pressures of modern existence that find us caught between scientific atheism and a need for spiritual and religious guidance. Here, Taylor finds a way of picturing ourselves within a secular age, remaining faithful to scientific rationalism, but still open to religion and a sense of a higher good. However, as I shall demonstrate, in his thesis Taylor misrepresents the Continental philosophical tradition (particularly Nietzsche and post-structuralism) that has itself sought to understand these cross-pressures of existence. Taking this misrepresentation, and specifically his reductive and colloquial analysis of Nietzsche, Camus, and Derrida, as my point of departure, I provide an alternative manner of thinking through the work of these writers, one that leads to a detailed analysis of Jean-Luc Nancy and his project the deconstruction of Christianity. In this analysis I argue that Nancy provides a manner of thinking that remains open and allows an experience of freedom, without seeking to close that sense of openness with explanation, nor maintaining that sense of openness with a conception of the divine.     

Leader performance and prototypicality: Their inter‐relationship and impact on leaders' identity entrepreneurship

Research has demonstrated that leader performance and leader prototypicality are both predictors of leader endorsement. While performance and prototypicality have generally been considered to be independent, this paper suggests that performance and prototypicality are interdependent and have a bi‐directional impact both on each other and on leaders' capacity to engage in identity entrepreneurship (i.e., to define shared group norms and ideals). Two experimental studies indicate that followers infer leaders' prototypicality from their performance and that a leader's prototypicality determines perceptions of performance (indicating reversed causality). Moreover, there is evidence that both performance and prototypicality enhance leaders' capacity to act as identity entrepreneurs. These findings extend our understanding of the mutually dependent causal relationship between followers' perceptions that a leader is ‘one of us’ and that he or she is ‘doing it well’. They also provide the first experimental evidence that these factors are joint determinants of leaders' identity entrepreneurship. Copyright © 2013 John Wiley & Sons, Ltd.     

Rethinking Professional Ethics in the Cost-Sharing Era

Changes in healthcare financing increasingly rely upon patient cost-sharing to control escalating healthcare expenditures. These changes raise new challenges for physicians that are different from those that arose either under managed care or traditional indemnity insurance. Historically, there have been two distinct bases for arguing that physicians should not consider costs in their clinical decisions—an “aspirational ethic” that exhorts physicians to treat all patients the same regardless of their ability to pay, and an “agency ethic” that calls on physicians to be trustworthy advisors to their patients. In the setting of greater patient cost-sharing, physicians' aspiration and agency roles increasingly conflict. Satisfactorily navigating the new terrain of consumer-driven healthcare requires physicians to consider these two roles and how they can best be reconciled so as to maximize quality of care while respecting the heterogeneity of patients' financial resources and willingness to pay.     

Daily Interactions and Affect in Older Adulthood: Family,Friends, and Perceived Support

Research suggests that family and friend support differentially impact well-being, although relatively few studies investigate how these relationships function day-to-day. The first goal of the study was to explore how interactions with family and with friends related to individuals’ daily experience of positive and negative emotion. The second goal of the study was to determine whether the perception that others were available to provide a particular type of support moderated the relationship between friend and family support and well-being each day. Multilevel Random Coefficient Modeling illuminated these linkages in data from 96 participants from Successful Aging in Context: The Macroenvironment and Daily Lived Experience (M _Age = 67 years, SD _Age = 4.9 years; range 58–86 years). Results revealed significant relationships between affect balance and satisfaction with the amount of support provided by family and by friends; in general, older adults reported a higher ratio of positive to negative affect on days they were more satisfied with the amount of support received from each source. Results of Level-2 analyses suggested that the perception that others were available to provide tangible assistance strengthened the relationship between satisfaction with family support and daily well-being; likewise, the availability of emotional support and advice strengthened the daily friend support–affect balance association. Overall, results suggest that global perceptions that network members are available to provide different types of support differentially augment the relationships between the social support older adults receive from friends and family each day and well-being; in so doing, these results suggest ways in which older adults can benefit most from existing support.     

Parenting processes,self-esteem,and aggression: A mediation model

The present study examined the relations between perceived maternal and paternal parenting processes and adolescent aggression, and to what extent these relations were mediated by self-esteem in a sample of 546 (43.8% males and 56.2% females) Turkish adolescents. Participants’ ages ranged from 14 to 18 with a mean of 15.91 years (SD = .95). Findings supported our hypothesized model of the effect of perceived parenting processes on aggression as being mediated through self-esteem for both maternal and paternal parenting measures. Specifically, self-esteem mediated the relations between parental closeness, monitoring, peer approval and adolescent aggression. Self-esteem is an important individual charecteristic to consider for prevention efforts of adolescent aggressive behaviors, along with key parenting behaviors.     

Philosophy of Science Between the Natural Sciences,the Social Sciences,and the Humanities: Introduction

This introduction provides a detailed summary of all papers of the special issue on the second conference of the German Society for Philosophy of Science: GWP.2016.