CONTINUOUS-TIME FILTERS FOR STATE ESTIMATION FROM POINT PROCESS MODELS OF NEURAL DATA

Neural spike trains, the primary communication signals in the brain, can be accurately modeled as point processes. For many years, significant theoretical work has been done on the construction of exact and approximate filters for state estimation from point process observations in continuous-time. We have previously developed approximate filters for state estimation from point process observations in discrete-time and applied them in the study of neural systems. Here, we present a coherent framework for deriving continuous-time filters from their discrete-counterparts. We present an accessible derivation of the well-known unnormalized conditional density equation for state evolution, construct a new continuous-time filter based on a Gaussian approximation, and propose a method for assessing the validity of the approximation following an approach by Brockett and Clark. We apply these methods to the problem of reconstructing arm reaching movements from simulated neural spiking activity from the primary motor cortex. This work makes explicit the connections between adaptive point process filters for analyzing neural spiking activity in continuous-time, and standard continuous-time filters for state estimation from continuous and point process observations.     

Expanding Horizons of Risk in Criminology

Few topics in the social sciences have witnessed as dramatic an increase in scholarly attention over the past two decades as the topic of risk. In this essay we examine sociological approaches to risk in criminological research and theory. After briefly describing the concept of risk in classical and neoclassical criminology, we turn our attention to three emerging social science perspectives on risk, those associated with the scholarship on risk society, edgework, and governmentality. We examine the new directions that these emerging ``risk paradigms'' open for criminological theory and research, including new perspectives on the motivation for criminal risk-taking, the organization of policing and criminal justice systems, and public and political responses to crime. We conclude by reviewing critiques of the scholarship associated with the new risk paradigms and by suggesting promising future directions for criminological research seeking to advance these perspectives.     

Space–time calibration of radar rainfall data

Motivated by a specific problem concerning the relationship between radar reflectance and rainfall intensity, the paper develops a space–time model for use in environmental monitoring applications. The model is cast as a high dimensional multivariate state space time series model, in which the cross-covariance structure is derived from the spatial context of the component series, in such a way that its interpretation is essentially independent of the particular set of spatial locations at which the data are recorded. We develop algorithms for estimating the parameters of the model by maximum likelihood, and for making spatial predictions of the radar calibration parameters by using realtime computations. We apply the model to data from a weather radar station in Lancashire, England, and demonstrate through empirical validation the predictive performance of the model.     

Multicollinearity problems and ridge regression in sociological models

The consequences of omitting relevant variables in regression analysis in order to cope with even moderate levels of multicollinearity can produce severe difficulties in subsequent theoretical interpretation of social science data. Use of ridge regression, a form of biased linear estimation, is explored. Application of ridge regression to a substantive sociological model is given to illustrate ridge regression's strengths as well as its limitations.     

Intimacy,Gender and Self Psychology: Considerations for Relationship Counselling

This paper reviews major conceptualisations of intimacy and the blocks, frequently attributed to gender, which are thought to contribute to problems in couple relationships. The paper concludes that gender is often not the limiting factor that inhibits intimacy in heterosexual couples. It may be more productive to consider individual rather than couple therapy to deal with impasses that appear to be associated with gender. Ideas from self psychology provide insights into how some requests for intimacy may be related to immature self‐object needs, which may better be handled through individual rather than couple therapy. A range of therapeutic goals and strategies that focus directly on intimacy are then outlined.     

Marital Assimilation Among Hispanics: Evidence of Declining Cultural and Economic Incorporation?*

Objective. We document intermarriage patterns between Hispanics and non‐Hispanic whites over the 1990 to 2000 period in 155 U.S. metropolitan areas and evaluate the effects of spatial, cultural, and economic assimilation on interdecade changes in intermarriage. We hypothesize that changes in Hispanic‐white intermarriage during the 1990s reflect changing spatial, cultural, and economic assimilation among U.S. Hispanics. Methods. We use data from the 1990 and 2000 Census Public Use Microdata Samples. Results. Analyses show that intermarriage between Hispanics and non‐Hispanic whites declined during the 1990s, a result fueled in part by burgeoning immigration of Hispanics, especially Mexicans. The 1990s also ushered in a period of increasing Hispanic segregation from non‐Hispanic whites, growing language barriers, and accelerated educational inequality, which also dampened Hispanic‐white intermarriage rates. Conclusions. Our results imply that the Hispanic population is at a transition point, if intermarriage rates are an indication, and possibly a new period of retrenchment in the assimilation process.     

The Role of Perceived Maternal Favoritism in Sibling Relations in Midlife

Data were collected from 708 adult children nested within 274 later‐life families from the Within‐Family Differences Study to explore the role of perceived maternal favoritism in the quality of sibling relations in midlife. Mixed‐model analyses revealed that regardless of which sibling was favored, perceptions of current favoritism and recollections of favoritism in childhood reduced closeness among siblings. Recollections of maternal favoritism in childhood were more important than perceptions of current favoritism in predicting tension among adult siblings, regardless of age. Taken together, the findings from this investigation are consistent with childhood studies showing that siblings have better relationships when they believe that they are treated equitably by their parents.     

Causes of Placement Breakdown for Foster Children Affected by Alcohol

A sample of 63 licensed foster parents who had fostered a child who was diagnosed with a disorder in the fetal alcohol spectrum were asked “What would make you consider ending a placement with a child who has a fetal alcohol spectrum disorder?” The responses to this question were grouped together by foster parents. The grouping data were subjected to multidimensional scaling and cluster analysis. Results indicated that foster parents would consider ending a placement if they felt they were being taken for granted, burned out, had insufficient information about the child, or if the child had serious behavior problems, caused harm to others in the home, or did not comply with household rules and routines. Discrepancies between the literature and study results were described and suggestions for future research were made.     

The Meaning of Good Parent–Child Relationships for Mexican American Adolescents

Perceptions of good parent–adolescent relationships were explored among 19 Mexican American high school students aged 14–17 who participated in focus group interviews on what it means for Mexican American teenagers to have good relationships with parents. Using a grounded theory approach, five general themes emerged in the responses, corresponding to open communication, instrumental and emotional support, indirect expressions of caring, parental control, and valued relationship qualities. Both genders described distinct relationships with mothers and fathers. Relationships with mothers were closer and more open than relationships with fathers, and mothers were seen as being more affectionate, lenient, and emotionally supportive, whereas fathers tended to express caring indirectly by providing instrumental and financial support and by just being there. Parental upbringing, culture, gender, and parental role expectations emerged as explanations for parents' behavior. Theoretical, methodological, and practical implications are discussed.