Conditional Gaussian mixture modelling for dietary pattern analysis

Summary.  Free-living individuals have multifaceted diets and consume foods in numerous combinations. In epidemiological studies it is desirable to characterize individual diets not only in terms of the quantity of individual dietary components but also in terms of dietary patterns. We describe the conditional Gaussian mixture model for dietary pattern analysis and show how it can be adapted to take account of important characteristics of self-reported dietary data. We illustrate this approach with an analysis of the 2000–2001 National Diet and Nutrition Survey of adults. The results strongly favoured a mixture model solution allowing clusters to vary in shape and size, over the standard approach that has been used previously to find dietary patterns.     

Linguistic Labels and Categorization in Infancy: Do Labels Facilitate or Hinder?

Although it is generally accepted that labels facilitate categorization in infancy, recent evidence suggests that infants and young children are more likely to process visual input when presented in isolation than when paired with nonlinguistic sounds or linguistic labels. These findings suggest that auditory input (when compared to a no‐auditory baseline) may hinder rather than facilitate categorization. This study assessed 8‐month‐olds' (n = 191) and 12‐month‐olds' (n = 81) abilities to form categories when images were paired with nonlinguistic sounds, linguistic labels, and when presented in isolation. Overall, infants accumulated more looking when visual stimuli were accompanied by sounds or labels; however, infants were more likely to categorize when the visual images were presented without an auditory stimulus.     

An Advocacy Coalition Framework Approach to Stakeholder Analysis: Understanding the Political Context of California Marine Protected Area Policy

There is a growing recognition that public policy controversiesare driven more by value differences than by technical deficiencies.Unfortunately, we have yet to develop, test, and refine systematicapproaches for understanding political systems. In this articleI explain how the advocacy coalition framework (ACF) can beused as a theoretical basis for understanding political contextvia a stakeholder analysis. An ACF stakeholder analysis widensthe attention of policy analysts toward subsystem-wide dynamicswith multiple actors who are motivated by their beliefs, structuretheir relationships into advocacy coalitions, and try to influencepolicy through utilizing multiple resources and venues. I illustratean ACF approach to stakeholder analysis in a scientificallycontentious political conflict over the establishment of marineprotected areas in California. I conclude with a summary ofcontributions to the ACF literature and the strengths and limitationsof conducting an ACF stakeholder analysis.     

Southern two-lined salamanders in urbanizing watersheds

Forested riparian buffers are an increasingly common method of mitigating the negative effects of impervious surface cover on water quality and wildlife habitat. We sampled larval southern two-lined salamanders (Eurycea cirrigera) in 43 streams, representing the range of impervious surface cover and forested riparian buffer width across Wake County, NC, USA. Larval abundance decreased with increasing impervious surface cover in the upstream catchment, but was not affected by buffer width. This is likely a result of an incomplete buffer system and culverts or other breaches along streams. Larval abundance increased with detritus cover in the stream to a threshold and then decreased as detritus continued to increase. As percent pebble substrate in the stream increased, especially in perennial streams, larval salamander abundance also increased. We suspect salamanders were unable to migrate with the water column during dry periods in intermittent streams with sedimented interstices below the surface, resulting in low abundances. A combination of increased peak flows and sedimentation, reduced base flow, and chemical changes likely reduces the abundance of salamanders in urban and suburban streams. We suggest creation of catchment-wide, unbreached buffers to maintain the integrity of stream habitats in urbanizing watersheds.     

Individual laboratory-measured discount rates predict field behavior

We estimate discount rates of 555 subjects using a laboratory task and find that these individual discount rates predict inter-individual variation in field behaviors (e.g., exercise, BMI, smoking). The correlation between the discount rate and each field behavior is small: none exceeds 0.28 and many are near 0. However, the discount rate has at least as much predictive power as any variable in our dataset (e.g., sex, age, education). The correlation between the discount rate and field behavior rises when field behaviors are aggregated: these correlations range from 0.09–0.38. We present a model that explains why specific intertemporal choice behaviors are only weakly correlated with discount rates, even though discount rates robustly predict aggregates of intertemporal decisions.     

Estimation of parameterized spatio-temporal dynamic models

Spatio-temporal processes are often high-dimensional, exhibiting complicated variability across space and time. Traditional state-space model approaches to such processes in the presence of uncertain data have been shown to be useful. However, estimation of state-space models in this context is often problematic since parameter vectors and matrices are of high dimension and can have complicated dependence structures. We propose a spatio-temporal dynamic model formulation with parameter matrices restricted based on prior scientific knowledge and/or common spatial models. Estimation is carried out via the expectation–maximization (EM) algorithm or general EM algorithm. Several parameterization strategies are proposed and analytical or computational closed form EM update equations are derived for each. We apply the methodology to a model based on an advection–diffusion partial differential equation in a simulation study and also to a dimension-reduced model for a Palmer Drought Severity Index (PDSI) data set.     

Remembering pre-independence childhoods in South India: interrogating autobiographies and identities

This article discusses the potential of autobiography for understanding histories of childhood, the effects of late-colonial social policy and the experience of change in India in the decades immediately preceding independence in 1947. This was an era characterized by both increased state intervention in the lives of poor Indian children and the growing influence of universalizing notions about modern childhood. Based on a detailed study of 55 autobiographies produced by those born between 1910 and 1940, the article analyses the ways in which childhood was imagined, defined and discussed by South Indians through memories that coalesce around the themes of innocence, play, education, work, family and social identity. It demonstrates that these narrations of memory also convey aspirations for contemporary Indian children through comparative reference to the binary of ‘today’ and ‘those days’. The article reveals the complexity of ideas and experiences at a local level which, despite the commonality of age, were refracted through the distinctions of gender, religion, race and class.     

The Federal Aviation Administration Airport Improvement Program: Who Benefits?

Public Organization Review - The objective of the (U.S.) Federal Aviation Administration Airport Improvement Program (AIP) is “to help in developing a nationwide system of public-use airports...     

The impact of tax rates, political partisanship and economic variables on the distribution of state and local tax burdens

This study finds that the effective state and local tax rate for the top 1% of income households as a percentage of the effective state and local tax rate for the bottom 20% of income households in 2002 is significantly influenced by whether a state has a multi-rate income tax, right-to-work laws, the liberalism of a state's electorate, the average tax burden in a state and past tax policy. Democratic Party strength in state government, Republican or Democratic Party institutional control of state government, change in real per capita income, a Democratic Governor and the change in the share of income going to the top 1% of income households are not significant predictors. The empirical results are identical for the top 2-5% of income households to the bottom 20% of income households.