Student perspectives on the relationship between a curve and its tangent in the transition from Euclidean Geometry to Analysis

The tangent line is a central concept in many mathematics and science courses. In this paper we describe a model of students’ thinking – concept images as well as ability in symbolic manipulation – about the tangent line of a curve as it has developed through students’ experiences in Euclidean Geometry and Analysis courses. Data was collected through a questionnaire administered to 196 Year 12 students. Through Latent Class Analysis, the participants were classified in three hierarchical groups representing the transition from a Geometrical Global perspective on the tangent line to an Analytical Local perspective. In the light of this classification, and through qualitative explanations of the students’ responses, we describe students’ thinking about tangents in terms of seven factors. We confirm the model constituted by these seven factors through Confirmatory Factor Analysis

Contact, Political Solidarity and Collective Action: An Indian Case Study of Relations between Historically Disadvantaged Communities

Research on the contact hypothesis has highlighted the role of contact in improving intergroup relations. Most of this research has addressed the problem of transforming the prejudices of historically advantaged communities, thereby eroding wider patterns of discrimination and inequality. In the present research, drawing on evidence from a cross-sectional survey conducted in New Delhi, we explored an alternative process through which contact may promote social change, namely by fostering political solidarity and empowerment amongst the disadvantaged. The results indicated that Muslim studentsˈ experiences of contact with other disadvantaged communities were associated with their willingness to participate in joint collective action to reduce shared inequalities. This relationship was mediated by perceptions of collective efficacy and shared historical grievances and moderated by positive experiences of contact with the Hindu majority. Implications for recent debates about the relationship between contact and social change are discussed

Predicting development of adolescent drinking behaviour from whole brain structure at 14 years of age

Adolescence is a common time for initiation of alcohol use and development of alcohol use disorders. The present study investigates neuroanatomical predictors for trajectories of future alcohol use based on a novel voxel-wise whole-brain structural equation modeling framework. In 1814 healthy adolescents of the IMAGEN sample, the Alcohol Use Disorder Identification Test (AUDIT) was acquired at three measurement occasions across five years. Based on a two-part latent growth curve model, we conducted whole-brain analyses on structural MRI data at age 14, predicting change in alcohol use score over time. Higher grey-matter volumes in the caudate nucleus and the left cerebellum at age 14 years were predictive of stronger increase in alcohol use score over 5 years. The study is the first to demonstrate the feasibility of running separate voxel-wise structural equation models thereby opening new avenues for data analysis in brain imaging

A longitudinal high-risk study of adolescent anxiety, depression and parent-severity on the developmental course of risk-adjustment

Background Adolescence is associated with developments in the reward system and increased rates of emotional disorders. Familial risk for depression may be associated with disruptions in the reward system. However, it is unclear how symptoms of depression and anxiety influence the development of reward-processing over adolescence and whether variation in the severity of parental depression is associated with hyposensitivity to reward in a high-risk sample. Methods We focused on risk-adjustment (adjusting decisions about reward according to the probability of obtaining reward) as this was hypothesized to improve over adolescence. In a one-year longitudinal sample (N = 197) of adolescent offspring of depressed parents, we examined how symptoms of depression and anxiety (generalized anxiety and social anxiety) influenced the development of risk-adjustment. We also examined how parental depression severity influenced adolescent risk-adjustment. Results Risk-adjustment improved over the course of the study indicating improved adjustment of reward-seeking to shifting contingencies. Depressive symptoms were associated with decreases in risk-adjustment over time while social anxiety symptoms were associated with increases in risk-adjustment over time. Specifically, depression was associated with reductions in reward-seeking at favourable reward probabilities only, whereas social anxiety (but not generalized anxiety) led to reductions in reward-seeking at low reward probabilities only. Parent depression severity was associated with lowered risk-adjustment in offspring and also influenced the longitudinal relationship between risk-adjustment and offspring depression. Conclusions Anxiety and depression distinctly alter the pattern of longitudinal change in reward-processing. Severity of parent depression was associated with alterations in adolescent offspring reward-processing in a high-risk sample

Which better predicts conduct problems? The relationship of trajectories of Conduct Problems, with ODD and ADHD Symptoms from childhood into adolescence

Background: To assess the co-occurrence in deviant trajectories of parent-rated symptoms of conduct disorder (CD), oppositional defiant disorder (ODD) and attention-deficit/hyperactivity disorder (ADHD) from age 4 to 18 years old in a general population sample of Dutch children. Methods: Developmental trajectories of CD, ODD, and ADHD were estimatedin a sample of 1,016 males and 1,060 females. Children's disruptive problem behaviors were rated at 5 time-points. The co-occurrence patterns between the deviant CD trajectory, and the high ODD and high ADHD trajectory were studied for males and females separately. Results: Four percent of males and 2% of females followed a deviant CD trajectory. Six percent of the sample followed a high ODD trajectory, and 5% a high ADHD trajectory. Engagement in the deviant CD trajectory was predicted by ODD and ADHD in females, but only by ODD in males. Conclusions: Although ADHD co-occurs with CD, the association between ADHD and CD is largely accounted for by accompanying ODD. Gender differences should be taken into account in understanding the onset of CD. © 2007 The Authors Journal compilation © 2007 Association for Child and Adolescent Mental Health

Measuring Metacognition in Cancer: Validation of the Metacognitions Questionnaire 30 (MCQ-30)

Objective The Metacognitions Questionnaire 30 assesses metacognitive beliefs and processes which are central to the metacognitive model of emotional disorder. As recent studies have begun to explore the utility of this model for understanding emotional distress after cancer diagnosis, it is important also to assess the validity of the Metacognitions Questionnaire 30 for use in cancer populations. Methods 229 patients with primary breast or prostate cancer completed the Metacognitions Questionnaire 30 and the Hospital Anxiety and Depression Scale pre-treatment and again 12 months later. The structure and validity of the Metacognitions Questionnaire 30 were assessed using factor analyses and structural equation modelling. Results Confirmatory and exploratory factor analyses provided evidence supporting the validity of the previously published 5-factor structure of the Metacognitions Questionnaire 30. Specifically, both pre-treatment and 12 months later, this solution provided the best fit to the data and all items loaded on their expected factors. Structural equation modelling indicated that two dimensions of metacognition (positive and negative beliefs about worry) were significantly associated with anxiety and depression as predicted, providing further evidence of validity. Conclusions These findings provide initial evidence that the Metacognitions Questionnaire 30 is a valid measure for use in cancer populations

Early risk indicators of internalizing problems in late childhood: A 9-year longitudinal study

Background: Longitudinal studies on risk indicators of internalizing problems in childhood are in short supply, but could be valuable to identify target groups for prevention. Methods: Standardized assessments of 294 children’s internalizing problems at the age of 2–3 years (parent report), 4–5 years (parent and teacher report) and 11 years (parent and teacher) were available in addition to risk indicators from the child, family and contextual domain. Results: Low socioeconomic status, family psychopathology at child age 2–3, parenting stress at child age 4–5 years, and parents’ reports of child internalizing problems at age 4–5 years were the strongest predictors of internalizing problems at the age of 11. If these early risk factors were effectively ameliorated through preventive interventions, up to 57% of internalizing cases at age 11 years could be avoided. Conclusions: Predictors from as early as 2–5 years of age are relevant for identifying children at risk of internalizing problems in late childhood. The methodological approach used in this study can help to identify children who are most in need of preventive interventions and help to assess the potential health gain and efficiency of such interventions. Keywords: Internalizing disorder, risk factors, prevention. Abbreviations: AF: attributable fraction; IRR: incidence rate ratio; LEQ: Life Events Questionnaire; NNT: numbers needed to be treated; RD: risk difference

Mix design considerations of foamed bitumen mixtures with reclaimed asphalt pavement material

In the present work, a mix design parametric study was carried out with the aim of proposing a practical and consistent mix design procedure for foamed bitumen mixtures (FBMs). The mix design parameters that were adopted in the study are mixing and compaction water content (MWC), compaction effort using a gyratory compactor and aggregate temperature. This parametric study was initially carried out on FBMs with virgin limestone aggregate without reclaimed asphalt pavement (RAP) material and a mix design procedure was proposed. This proposed methodology was also found to apply to FBMs with RAP. A detailed consideration was also given to characterising the RAP material so as to understand its contribution to the mechanical properties of FBMs. Optimum MWC was achieved by optimising mechanical properties such as indirect tensile stiffness modulus and indirect tensile strength (ITS-dry and ITS-wet). A rational range of 75–85% of optimum water content obtained by the modified Proctor test was found to be the optimum range of MWC that gives optimum mechanical properties for FBMs. It was also found that the presence of RAP influenced the design foamed bitumen content, which means that treating RAP as black rock in FBM mix design is not appropriate. To study the influence of bitumen and water during compaction, modified Proctor compaction and gyratory compaction were employed on mixes with varying amounts of water and bitumen. By this, the work also evaluated the validity of the total fluid (water + bitumen) concept that is widely used in bitumen–emulsion-treated mixes, and found it not to be applicable

Fatigue Intervention by Nurses Evaluation - The FINE Trial. A randomised controlled trial of nurse led self-help treatment for patients in primary care with chronic fatigue syndrome: study protocol. [ISRCTN74156610]

Background: Chronic fatigue syndrome, also known as ME (CFS/ME), is a condition characterised primarily by severe, disabling fatigue, of unknown origin, which has a poor prognosis and serious personal and economic consequences. Evidence for the effectiveness of any treatment for CFS/ME in primary care, where most patients are seen, is sparse. Recently, a brief, pragmatic treatment for CFS/ME, based on a physiological dysregulation model of the condition, was shown to be successful in improving fatigue and physical functioning in patients in secondary care. The treatment involves providing patients with a readily understandable explanation of their symptoms, from which flows the rationale for a graded rehabilitative plan, developed collaboratively with the therapist. The present trial will test the effectiveness and cost-effectiveness of pragmatic rehabilitation when delivered by specially trained general nurses in primary care. We selected a client-centred counselling intervention, called supportive listening, as a comparison treatment. Counselling has been shown to be as effective as cognitive behaviour therapy for treating fatigue in primary care, is more readily available, and controls for supportive therapist contact time. Our control condition is treatment as usual by the general practitioner (GP). Methods and design: This study protocol describes the design of an ongoing, single-blind, pragmatic randomized controlled trial of a brief (18 week) self-help treatment, pragmatic rehabilitation, delivered by specially trained nurse-therapists in patients' homes, compared with nurse-therapist delivered supportive listening and treatment as usual by the GP. An economic evaluation, taking a societal viewpoint, is being carried out alongside the clinical trial. Three adult general nurses were trained over a six month period to deliver the two interventions. Patients aged over 18 and fulfilling the Oxford criteria for CFS are assessed at baseline, after the intervention, and again one year later. Primary outcomes are self-reported physical functioning and fatigue at one year, and will be analysed on an intention-to-treat basis. A qualitative study will examine the interventions' mechanisms of change, and also GPs' drivers and barriers towards referral

Gender differences in developmental links between antisocial behavior, friends' antisocial behavior and peer rejection in childhood: Results in two cultures

This study addressed gender differences in the developmental links among antisocial behavior, friends' anti-social behavior, and peer rejection. High and increasing, moderate, and low antisocial developmental trajectories were identified among 289 Dutch children, ages 7 to 10, and 445 French-Canadian children, ages 9 to 12. Only boys followed the high trajectory. These boys had more deviant friends and were more often rejected than other children. A minority of girls followed the moderate antisocial behavior trajectory. These girls had fewer deviant friends than moderate antisocial boys, but moderate antisocial boys and girls were equally likely to be rejected. The influence of friends and poor peer relations plays a crucial but different role in the development of antisocial behavior among boys and girls. © 2005 by the Society for Research in Child Development, Inc. All rights reserved