Tests for a difference in timing of physiological response between two brain regions measured by using functional magnetic resonance imaging

Summary.  Functional magnetic resonance imaging (FMRI) measures the physiological response of the human brain to experimentally controlled stimulation. In a periodically designed experiment it is of interest to test for a difference in the timing (phase shift) of the response between two anatomically distinct brain regions. We suggest two tests for an interregional difference in phase shift: one based on asymptotic theory and one based on bootstrapping. Whilst the two procedures differ in some of their assumptions, both tests rely on employing the large number of voxels (three-dimensional pixels) in non-activated brain regions to take account of spatial autocorrelation between voxelwise phase shift observations within the activated regions of interest. As an example we apply both tests, and their counterparts assuming spatial independence, to FMRI phase shift data that were acquired from a normal young woman during performance of a periodically designed covert verbal fluency task. We conclude that it is necessary to take account of spatial autocovariance between voxelwise FMRI time series parameter estimates such as the phase shift, and that the most promising way of achieving this is by modelling the spatial autocorrelation structure from a suitably defined base region of the image slice.     

Illuminating gendered organization assumptions

One key to why organizations have been less successful at integrating a work–family agenda into their organizational cultures is that workplaces have failed to consider how gender assumptions influence workplace practices, policies and cultures. This paper presents a theoretical framework for considering how gender role assumptions have prevented organizational attempts to become family friendly. Further, this paper uses an organizational case study to illustrate this point. Specifically, a theory of gendered organizations is used to frame an analysis of 30 employee interviews. Data suggest that gendered organizational assumptions inherent to several workplace policies and practices contribute to employee strain associated with negotiating the demands of life on and off the job. Further, the findings show that these gendered organizational assumptions prevent organizations from developing workplace cultures responsive to employees' work, family and personal needs. A brief review of the interdisciplinary work–family field is presented, followed by a discussion of gendered organizations. Then, using interview data collected from management and ‘front‐line’ female and male workers employed at a municipal government, this paper examines how workplace practices, presumably gender neutral, affect employees and the organizational culture in which they work.     

土族民间信仰中的神祗与仪式——对民和土族村寨保护神信仰及相关仪式的人类学考察

本文在前人调查研究基础上,结合笔者在田野调查中所取得的第一手资料,对民和三川地区土族村寨中供奉的主要神祇和相关仪式及其内涵、成因进行了论述。     

Estimation of the intercept parameter for linear regression model with uncertain non-sample prior information

This paper considers alternative estimators of the intercept parameter of the linear regression model with normal error when uncertain non-sample prior information about the value of the slope parameter is available. The maximum likelihood, restricted, preliminary test and shrinkage estimators are considered. Based on their quadratic biases and mean square errors the relative performances of the estimators are investigated. Both analytical and graphical comparisons are explored. None of the estimators is found to be uniformly dominating the others. However, if the non-sample prior information regarding the value of the slope is not too far from its true value, the shrinkage estimator of the intercept parameter dominates the rest of the estimators.     

Socioeconomic Status and Patterns of Parent–Adolescent Interactions

This study investigated reciprocity in parent–adolescent interactions among 102 families from lower or higher socioeconomic status (SES) backgrounds. Negative behaviors between parents and adolescents were more reciprocal (strongly correlated) in higher SES than lower SES families, and this reciprocity correlated with higher family relationship quality. Lower SES families exhibited reciprocity related to withdrawn behaviors. Reciprocity of these behaviors also correlated with higher relationship quality. Results suggest that SES differences provide insights into a more complex understanding of family relationships within contexts, and importantly, suggest that different types of reciprocity may each have its own adaptive value in families from different SES backgrounds.     

Self‐Perceived Gender Typicality and the Peer Context During Adolescence

This research examined adolescents' gender identity in relation to the peer context and their self‐concept. Participants were 229 adolescents who completed questionnaire measures of self‐concept and multidimensional gender identity. Regression analysis indicated peer acceptance partially mediated the relation between self‐perceived gender typicality and self‐worth. Cluster analysis revealed four groups of adolescents with differing profiles of self‐perceived gender typicality, felt peer pressure for gender conformity, and peer acceptance. Findings highlight the inherently social and contextual nature of gender identity. Also, the pathologizing of gender‐nonconforming youth is discussed.     

Approaches for the direct estimation of u,and demographic contributions to u,using capture-recapture data

We first consider the estimation of the finite rate of population increase or population growth rate, u i , using capture-recapture data from open populations. We review estimation and modelling of u i under three main approaches to modelling openpopulation data: the classic approach of Jolly (1965) and Seber (1965), the superpopulation approach of Crosbie & Manly (1985) and Schwarz & Arnason (1996), and the temporal symmetry approach of Pradel (1996). Next, we consider the contributions of different demographic components to u i using a probabilistic approach based on the composition of the population at time i + 1 (Nichols et al., 2000b). The parameters of interest are identical to the seniority parameters, n i , of Pradel (1996). We review estimation of n i under the classic, superpopulation, and temporal symmetry approaches. We then compare these direct estimation approaches for u i and n i with analogues computed using projection matrix asymptotics. We also discuss various extensions of the estimation approaches to multistate applications and to joint likelihoods involving multiple data types.     

Graphical models for skew-normal variates

This paper explores the usefulness of the multivariate skew-normal distribution in the context of graphical models. A slight extension of the family recently discussed by Azzalini & Dalla Valle (1996 ) and Azzalini & Capitanio (1999 ) is described, the main motivation being the additional property of closure under conditioning. After considerations of the main probabilistic features, the focus of the paper is on the construction of conditional independence graphs for skew-normal variables. Necessary and sufficient conditions for conditional independence are stated, and the admissible structures of a graph under restriction on univariate marginal distribution are studied. Finally, parameter estimation is considered. It is shown how the factorization of the likelihood function according to a graph can be rearranged in order to obtain a parameter based factorization.