Form Perception of Partly Occluded Shapes in 4‐Month‐Old Infants

Two habituation experiments were conducted to investigate how 4‐month‐old infants perceive partly occluded shapes. In the first experiment, we presented a simple, partly occluded shape to the infants until habituation was reached. Then we showed either a probable completion (one that would be predicted on the basis of both local and global cues) or an improbable completion. Longer looking times were found for the improbably completed shape (compared to probable and control conditions), suggesting that the probable shape was perceived during partial occlusion. In the second experiment, infants were habituated to more ambiguous partly occluded shapes, where local and global cues would result in different completions. For adults, the percept of these shapes is usually dominated by global influences. However, after habituation the infants looked longer at the globally completed shapes. These results suggest that by the age of 4 months, infants are able to infer the perceptual completion of partly occluded shapes, but for more ambiguous shapes, this completion seems to be dominated by local influences.     

Bayesian updating of atmospheric dispersion after a nuclear accident

Summary.  We consider a Bayesian forecasting system to predict the dispersal of contamination on a large scale grid in the event of an accidental release of radioactivity. The statistical model is built on a physical model for atmospheric dispersion and transport called MATCH. Our spatiotemporal model is a dynamic linear model where the state parameters are the (essentially, deterministic) predictions of MATCH; the distributions of these are updated sequentially in the light of monitoring data. One of the distinguishing features of the model is that the number of these parameters is very large (typically several hundreds of thousands) and we discuss practical issues arising in its implementation as a realtime model. Our procedures have been checked against a variational approach which is used widely in the atmospheric sciences. The results of the model are applied to test data from a tracer experiment.     

A circular-cone test for testing homogeneity against a simple tree order

Several methods exist for the problem of testing the equality of several treatments against the one-sided alternative that the treatments are better than the control. These methods include Dunnett's test, Bartholomew's likelihood-ratio test, the Abelson-Tukey-Schaafsma-Smid optimal-contrast test, and the multiple-contrast test of Mukerjee, Robertson, and Wright. A new test is proposed based on an approximation of the likelihood-ratio test of Bartholomew. This test involves using a circular cone in place of the alternative-hypothesis cone. The circular-cone test has excellent power characteristics similar to those of Bartholomew's test. Moreover, it has the advantages of being simpler to compute and may be used with unequal sample sizes.     

An alternative to farmer age as an indicator of life-cycle stage: The case for a farm family age index

In studies of farming, the age of the principal decision-maker (PDM) has been associated with numerous farm structural and managerial features and has been widely accepted as a good indicator of the influence of life-cycle factors on decision-making. As such, it has become an important aspect of many quantitative studies of agricultural change. However, contemporary studies of family farming demonstrate that the concept of a single PDM in family farms is becoming an anachronism as alternative enterprises, pluriactivity and the scale of family farms force more diffuse management/operating systems. This raises questions concerning whether the age of the PDM can still be taken as representative of farm structure, strategy or life-cycle stage? Using a study conducted in the Grampian Mountains region of Scotland in 2003 this note investigates the impact of using an alternative index—compiled by averaging the age of family members working on the farm. It suggests that PDM age is a relatively poor indicator of farm structural and managerial features compared to a family age index and calls for researchers to think about alternative approaches to measuring ‘age’ as an indicator.     

Understanding manager resistance to blockchain systems

Blockchain technology has received much attention in the media and there is an increasing interest amongst organizations within financial services due to the potential benefits. As blockchain-based systems are a nascent technology, the requirements of the technology need to be understood, to allow blockchain systems to be successfully integrated within financial service organizations. There are gaps in academic research in understanding how managers evaluate the value of a blockchain-based system. This study develops a model to explain manager resistance to implementing blockchain-based systems in financial services organizations. This research advances the theoretical understanding of managers’ perspectives on blockchain-based systems and models their resistance to blockchain technology.     

Context Matters: Differential Effects of Discrimination by Environmental Context on Depressive Symptoms Among College Students of Color

Clinical Social Work Journal - Experiences with more subtle racism – which have been called microaggressions – have a host of negative effects on health, mental health, educational...     

Conceptualizing reflection in experience-based workplace learning

This paper seeks to understand key dimensions of reflection in experience-based workplace learning for research being collaboratively undertaken by scholars in Dutch and US research institutions. We systematically explore and compare Tara Fenwick’s analysis of five perspectives on cognition to distinguish among constructivist, psychoanalytic, situative, critical-cultural, and enactivist perspectives on reflection. Our aim is to examine how to conceptualize reflection so that one or more perspectives can complement our understanding of learning through experience at work. We position reflection not only from a practical but also from a theoretical perspective that moves beyond the individual focus of the constructivist perspective. Fenwick’s five perspectives are described in terms of whether and how reflection is utilized, key activities in the process of reflection, relative focus on the individual and/or the context, triggers for reflection, role of power and positionality, role of emotions, and reflection outcomes. We conclude that adding other lenses to the dominant constructivist perspective helps expand our understanding of reflection as well as identify and attend to other tools, people, and factors in the work situation that influence reflection processes and learning outcomes. The paper closes with a discussion of promising new approaches that have emerged since Fenwick’s analysis.     

Intimate Partner Violence,Minority Stress,and Sexual Risk-Taking Among U.S. Men Who Have Sex With Men

This article examines the prevalence of intimate partner violence (IPV) among a national sample of Internet-recruited U.S. men who have sex with men (MSM) (n = 1,575), and associations between reporting of IPV, minority stress, and sexual risk-taking. Five outcomes are examined: experiences of physical and sexual violence, perpetration of physical and sexual violence, and unprotected anal intercourse (UAI) at last sexual encounter. MSM who reported experiencing more homophobic discrimination and internalized homophobia were more likely to report experiences of IPV. The results point to the need for prevention messages to address the external and internal stressors that influence both violence and sexual risk among MSM.     

Access to Water in the Slums of Sub‐Saharan Africa

This article reviews the changing perspectives for improving access to water in the slums of developing countries, especially in sub‐Saharan Africa. While much of the literature continues to maintain an aversion to state‐led urban development policies, there is now increasing emphasis on the importance of informal, small‐scale providers and communitarian initiatives, following the many failures of privatisation. The article argues that market‐oriented solutions are inappropriate for sub‐Saharan African countries where over two‐thirds of the urban population live in squatter settlements with multidimensional challenges.     

A reflected feature space for CART

We present an algorithm for learning oblique decision trees, called HHCART(G). Our decision tree combines learning concepts from two classification trees, HHCART and Geometric Decision Tree (GDT). HHCART(G) is a simplified HHCART algorithm that uses linear structure in the training examples, captured by a modified GDT angle bisector, to define splitting directions. At each node, we reflect the training examples with respect to the modified angle bisector to align this linear structure with the coordinate axes. Searching axis parallel splits in this reflected feature space provides an efficient and effective way of finding oblique splits in the original feature space. Our method is much simpler than HHCART because it only considers one reflected feature space for node splitting. HHCART considers multiple reflected feature spaces for node splitting making it more computationally intensive to build. Experimental results show that HHCART(G) is an effective classifier, producing compact trees with similar or better results than several other decision trees, including GDT and HHCART trees.