Effects of drift and noise on the optimal sliding window size for data stream regression models

The analysis of non stationary data streams requires a continuous adaption of the model to the relevant most recent data. This requires that changes in the data stream must be distinguished from noise. Many approaches are based on heuristic adaptation schemes. We analyze simple regression models to understand the joint effects of noise and concept drift and derive the optimal sliding window size for the regression models. Our theoretical analysis and simulations show that a near optimal window size can be crucial. Our models can be used as benchmarks for other models to see how they cope with noise and drift.     

Minority Language Proficiency of Adolescent Immigrant Children in England,Germany, the Netherlands,and Sweden

We study minority language proficiency of adolescent immigrant children in England, Germany, the Netherlands and Sweden. We elaborate on theoretical mechanisms of exposure, efficiency and non-economic incentives of minority language acquisition. Using data from adolescent immigrant children in England, Germany, the Netherlands and Sweden, we find evidence for the role of exposure in that immigrant children who were born abroad were more proficient than those born in the host country. Exposure via the percentage of co-ethnics at school is positively related to minority proficiency, whereas parental proficiency in the destination language is negatively associated. Also belonging to a larger immigrant group increases exposure to the minority language and results in language retention. Efficiency in terms of cognitive abilities does not play a role. Non-economic incentives to retain the minority language, indicated by the ethnic identification of parents, is positively related to the child’s minority language proficiency and this relationship is stronger when the quality of the parent-child relationship is higher.     

Maisie’s Spasms: Transferential Poetics in Henry James and Wilfred Bion

ABSTRACT

This essay offers a reading of Henry James’s midcareer novel What Maisie Knew (1897) as a study in group psychology. Maisie, James’s child heroine, is at the center of an expanding and transforming family group that includes various governesses as well as her divorced parents’ multiple new partners. I set James’s novel beside Bion’s Experiences in Groups and Other Papers (1961) and its Kleinian approach to the continuities and discontinuities between individual and group experience. Rather than insisting (as Freud tends to) only on a narrative of individuation and adaptation, Bion emphasizes the necessity and difficulty an individual inevitably experiences in making contact with the emotional life of the group in which she lives. James casts the frustrating necessity of group experience in entirely theatrical terms, figuring Maisie from the start as a spectator to, and eventually an active participant in, the affective circuits of those around her. In my reading the transferential poetics of James and Bion make available the affective, transindividual nature of knowing as a contingent activity that takes place between persons and other objects. The essay concludes by unfolding some of the surprising televisual aspects of James’s late style.     

Trading Later Rewards for Current Pleasure: Pornography Consumption and Delay Discounting

Internet pornography is a multi-billion-dollar industry that has grown increasingly accessible. Delay discounting involves devaluing larger, later rewards in favor of smaller, more immediate rewards. The constant novelty and primacy of sexual stimuli as particularly strong natural rewards make Internet pornography a unique activator of the brain's reward system, thereby having implications for decision-making processes. Based on theoretical studies of evolutionary psychology and neuroeconomics, two studies tested the hypothesis that consuming Internet pornography would relate to higher rates of delay discounting. Study 1 used a longitudinal design. Participants completed a pornography use questionnaire and a delay discounting task at Time 1 and then again four weeks later. Participants reporting higher initial pornography use demonstrated a higher delay discounting rate at Time 2, controlling for initial delay discounting. Study 2 tested for causality with an experimental design. Participants were randomly assigned to abstain from either their favorite food or pornography for three weeks. Participants who abstained from pornography use demonstrated lower delay discounting than participants who abstained from their favorite food. The finding suggests that Internet pornography is a sexual reward that contributes to delay discounting differently than other natural rewards. Theoretical and clinical implications of these studies are highlighted.     

More than profits? The contribution of the slave trade to the Dutch economy: assessing Fatah-Black and Van Rossum

We assess Fatah-Black and Van Rossum’s analysis of the Dutch slave trade by detailing six 1750s voyages of the Middelburg Commercial Company. The costs of transporting captives from Africa to Suriname are explored along with their relation to the Dutch economy. We also examine the implications of the concept ‘gross margin’, which is central to Fatah-Black and Van Rossum’s work. We find that, given the nature of the transport costs, the impact of the slave trade on the Dutch economy was minimal, and more generally that gross margin is not a useful measure for testing the Williams Thesis.     

Adaptation and Evaluation of a Nonviolent Resistance Intervention for Foster Parents: A Progress Report

Foster care faces serious challenges, such as behavioral problems in foster children and parental stress and ineffective parenting behavior in foster parents. The results of a pilot study that evaluated a training program for foster parents based on nonviolent resistance are described. In a pretest–posttest design, data were collected from 25 families. Significant reductions in externalizing, internalizing, and total problem behavior in the foster children and in parenting stress were found. Using a reliable change index, significant improvements in externalizing, internalizing, and total problem behavior were found in, respectively, 72, 44, and 80% of the cases. Most improvements proved to be clinically relevant. Effect sizes ranged from medium to large for problem behavior, and from small to medium for parenting stress.     

The ‘New Approach’ to Public Sector Reforms in Ghana: A Case of Politics as Usual or a Genuine Attempt at Reform?

Public sector reforms continue to preoccupy governments all over the world, compelled by the need to ‘get the state right’ through better policy development and implementation. Developing countries see this as the path to a developmental state. This article examines Ghana's quest to build such a state through its new public sector reforms, originally hailed in hyperbolic terms. We argue that the rejection of a top‐down and bottom‐up synergy in favour of an exclusively top‐down approach dooms this effort to failure.     

Bad neighbors: urban habitats increase cankerworm damage to non-host understory plants

Plants growing in vegetationally diverse habitats or near taxonomically distinct neighbors often experience less herbivory than plants in more simple habitats. When plants experience more herbivory in these situations it is called associational susceptibility and is most common when herbivores spill from their preferred plant host onto neighboring plants. Cankerworms are common pests of urban trees that have been shown in forests to disperse from preferred to less preferred hosts. I found that two common characteristics of urban habitats, low vegetational diversity and exotic plants, affect cankerworm herbivory of non-host understory plants. In an urban landscape I measured cankerworm herbivory on native dogwood trees growing in the open and below cankerworm host and non-host trees. Herbivory of native dogwoods was ten times greater below cankerworm hosts than on trees below non-hosts or in the open. At an arboretum I measured herbivory of native and exotic plants growing below cankerworm hosts in simple landscape plantings and in natural forests. Associational susceptibility of native dogwoods and Rhododendron spp. disappeared when they were growing in complex natural forests even though cankerworm hosts were more abundant. Cankerworms consistently preferred native plant species more than exotic congeners in laboratory experiments. As such, exotic plants experienced very little herbivory regardless of habitat. Herbivorous pests are often more abundant on urban plants than plants in natural habitats. My research shows that, although some plants experience more herbivory when growing near cankerworm hosts, increasing urban habitat complexity could reduce pest damage overall.