Comments on “bootstrapping time series models”

Many applied workers are strongly oriented to residual analysis for assessing model adequacy. Formal test statistics of adequacy however are frequently derived from likelihood theory, particularly through Lagrange Multipliers. In contraGt, the present paper derives the formal statistics by concentrating Upon the distribution of residuals. It is shown that most existing tests can be derived in this way from a few elementary principles of specification analysis. One advantage of this alternative methodology is that it highlights some difficulties in existing approaches and simultaneously indicates a resolution of them; a good example being testing for heteroscedasticity in simultaneous equations. Other issues such as independence and robustness of diagnostic tests are also easily explored within the proposed framework.     

The effectiveness and safety of ginger for pregnancy-induced nausea and vomiting: A systematic review

BackgroundGinger has been used throughout the world as a therapeutic agent for centuries. The herb is increasingly used in Western society also, with one of the most common indications being pregnancy-induced nausea and vomiting (PNV).ObjectivesTo examine the evidence for the safety and effectiveness of ginger for PNV.MethodsRandomised controlled trials (RCTs) of ginger and PNV were sourced from CINAHL, the Cochrane library, MEDLINE and TRIP. The methodological quality of RCTs was assessed using the Critical Appraisal Skills Programme (CASP) tool.ResultsFour RCTs met the inclusion criteria. All trials found orally administered ginger to be significantly more effective than placebo in reducing the frequency of vomiting and intensity of nausea. Adverse events were generally mild and infrequent.ConclusionThe best available evidence suggests that ginger is a safe and effective treatment for PNV. However, there remains uncertainty regarding the maximum safe dosage of ginger, appropriate duration of treatment, consequences of over-dosage, and potential drug–herb interactions; all of which are important areas for future research.     

Evaluating a social work introductory programme

Many social work programmes spend considerable time at the end of the course consolidating learning experiences, looking to employment issues, the nature of supervisory contracts, future training needs and so on (see for example the Janus week at Robert Gordon University, Aberdeen). On a social level students also experience a round of parties, a graduation ceremony, the collection of certificates and formal farewells. Such activities are fairly predictable rites of passage. Whilst the importance of beginnings in social work practice is part of the folklore, little has been said or written about the actual process of induction onto social work training programmes. In this article we focus on the beginning of such a programme leading to an award of MA and Diploma in Social Work. We analyse what happens, describe the structures and under-pinning theories and conclude by arguing that the start of a course is an important land-mark for students' relationships with each other, with teaching staff and their own self-perceptions and sense of empowerment. Our reflection on these processes has been useful in looking at the conscious and unconscious messages given by ourselves and our institution.

Firstly, we briefly explore perspectives emanating from broad sociological discourse about the nature of professionalisation. We can then reflect on the perspective of anthropology which raises useful notions of initiation, celebration and ritual. We are particularly interested in looking at the power relationship between staff and students and at learning styles. Theory therefore demands that we look at this introduction in other than mechanistic or rational ways.

The second part of this article considers a three day introduction to a social work programme, concentrating on styles of learning and the inherent issues of power relationships.     

Religion,Age, and Crime: Do Religious Traditions Differentially Impact Juvenile Versus Adult Violence?

A growing body of empirical research demonstrates that the relative presence of religious adherents at the community-level has important relationships with rates of crime and violence. Less understood is how adherence to specific religious traditions (e.g., evangelical Protestant, Catholic, mainline Protestant) is associated with rates of crime, especially across particular age groups toward which religious traditions devote varying degrees of structural and cultural resources. Using data from the Religious Congregations and Membership Survey and age-specific arrest data from the Uniform Crime Reporting program in 2010, the current study finds that the impact of religious adherence on crime varies by religious tradition and across juvenile versus adult crime. Specifically, evangelical Protestant adherence is negatively associated with juvenile but not adult violence, while Catholic adherence is associated with reduced adult but not juvenile violence, net of controls. Implications for research on religious contexts and crime, as well as policy, are discussed.     

Morality,Relationality, and Listening Pedagogy in Language Education

Listening pedagogy in language education treats listening proficiency almost exclusively as a function or skill, the purpose of which is to generate products or outcomes desired by language users. Though listening is rhetorically acknowledged to be an active and complex process of making meanings within contexts and relationships, in practice teacher education and pedagogical discourse treat listening simply as a linguistic transaction and listening pedagogy as a technical and instrumental process of skill building, with the goal of enabling learners fluently to perform such transactions. Such a means-to-ends orientation, however, is inadequate or insufficient to encompass holistic moral and relational dimensions inherent in listening. These dimensions might be added to language listening pedagogy by, for example, broadening the idea of “dialogue” to include more open-ended perspectives from other disciplines, contextualizing the relationality of typical coursebook listening passages, and working with metaphors such as hospitality that encourage a high attentiveness to communication accompanied by a high moral respect for persons.     

Conditional Desirability

Conditional attitudes are not the attitudes an agent is disposed to acquire in event of learning that a condition holds. Rather they are the components of agent's current attitudes that derive from the consideration they give to the possibility that the condition is true. Jeffrey's decision theory can be extended to include quantitative representation of the strength of these components. A conditional desirability measure for degrees of conditional desire is proposed and shown to imply that an agent's degrees of conditional belief are conditional probabilities. Rational conditional preference is axiomatised and by application of Bolker's representation theorem for rational preferences it is shown that conditional preference rankings determine the existence of probability and desirability measures that agree with them. It is then proven that every conditional desirability function agrees with an agent's conditional preferences and, under certain assumptions, every desirability function agreeing with an agent's conditional preferences is a conditional desirability function agreeing with her unconditional preferences.     

Exploring Gender Differences on Internalizing and Externalizing Behavior Among Maltreated Youth: Implications for Social Work Action

This purpose of this study was to explore the moderating influence of gender on the relationship between child maltreatment and internalizing symptoms (e.g., affective and somatic problems) and externalizing behavior (e.g., rule breaking behavior and aggression) among children aged 7–12 years old. Using a longitudinal comparison group design and a sample of 300 youth of which 56% (n = 168) had substantiated cases of child maltreatment, results of a structural equation modeling revealed that internalizing symptoms exerted a mediating influence that was conditioned by gender. Only girls’ internalizing symptoms were found to mediate the link between child maltreatment and externalizing behavior while a direct relationship between maltreatment and externalizing behavior was found among boys. These findings provide evidence for gender differences in the pathways between being child maltreatment and maladaptive thoughts, feelings, and behaviors. Thus, adapting evidence-based strategies that target gender specific internalizing behaviors and externalizing behaviors among maltreated youth may significantly reduce the risk of short and long-term maladaptive behavior.     

IV Quantile Regression for Group‐Level Treatments,With an Application to the Distributional Effects of Trade

We present a methodology for estimating the distributional effects of an endogenous treatment that varies at the group level when there are group‐level unobservables, a quantile extension of Hausman and Taylor, 1981. Because of the presence of group‐level unobservables, standard quantile regression techniques are inconsistent in our setting even if the treatment is independent of unobservables. In contrast, our estimation technique is consistent as well as computationally simple, consisting of group‐by‐group quantile regression followed by two‐stage least squares. Using the Bahadur representation of quantile estimators, we derive weak conditions on the growth of the number of observations per group that are sufficient for consistency and asymptotic zero‐mean normality of our estimator. As in Hausman and Taylor, 1981, micro‐level covariates can be used as internal instruments for the endogenous group‐level treatment if they satisfy relevance and exogeneity conditions. Our approach applies to a broad range of settings including labor, public finance, industrial organization, urban economics, and development; we illustrate its usefulness with several such examples. Finally, an empirical application of our estimator finds that low‐wage earners in the United States from 1990 to 2007 were significantly more affected by increased Chinese import competition than high‐wage earners.     

Order-free co-regionalized areal data models with application to multiple-disease mapping

With the ready availability of spatial databases and geographical information system software, statisticians are increasingly encountering multivariate modelling settings featuring associations of more than one type: spatial associations between data locations and associations between the variables within the locations. Although flexible modelling of multivariate point-referenced data has recently been addressed by using a linear model of co-regionalization, existing methods for multivariate areal data typically suffer from unnecessary restrictions on the covariance structure or undesirable dependence on the conditioning order of the variables. We propose a class of Bayesian hierarchical models for multivariate areal data that avoids these restrictions, permitting flexible and order-free modelling of correlations both between variables and across areal units. Our framework encompasses a rich class of multivariate conditionally autoregressive models that are computationally feasible via modern Markov chain Monte Carlo methods. We illustrate the strengths of our approach over existing models by using simulation studies and also offer a real data application involving annual lung, larynx and oesophageal cancer death-rates in Minnesota counties between 1990 and 2000.