Bayesian influence diagnostics in radiocarbon dating

Linear models constitute the primary statistical technique for any experimental science. A major topic in this area is the detection of influential subsets of data, that is, of observations that are influential in terms of their effect on the estimation of parameters in linear regression or of the total population parameters. Numerous studies exist on radiocarbon dating which propose a value consensus and remove possible outliers after the corresponding testing. An influence analysis for the value consensus from a Bayesian perspective is developed in this article.     

Confidence Intervals for the Hyperparameters in Structural Models

This article deals with the bootstrap as an alternative method to construct confidence intervals for the hyperparameters of structural models. The bootstrap procedure considered is the classical nonparametric bootstrap in the residuals of the fitted model using a well-known approach. The performance of this procedure is empirically obtained through Monte Carlo simulations implemented in Ox. Asymptotic and percentile bootstrap confidence intervals for the hyperparameters are built and compared by means of the coverage percentages. The results are similar but the bootstrap procedure is better for small sample sizes. The methods are applied to a real time series and confidence intervals are built for the hyperparameters.     

Confidence Intervals for the Youden Index and Corresponding Optimal Cut-Point

A global measure of biomarker effectiveness is the Youden index, the maximum difference between sensitivity, the probability of correctly classifying diseased individuals, and 1-specificity, the probability of incorrectly classifying healthy individuals. The cut-point leading to the index is the optimal cut-point when equal weight is given to sensitivity and specificity. Using the delta method, we present approaches for estimating confidence intervals for the Youden index and corresponding optimal cut-point for normally distributed biomarkers and also those following gamma distributions. We also provide confidence intervals using various bootstrapping methods. A comparison of interval width and coverage probability is conducted through simulation over a variety of parametric situations. Confidence intervals via delta method are shown to have both closer to nominal coverage and shorter interval widths than confidence intervals from the bootstrapping methods.     

Differential Developmental Profiles of Adolescents Using Sexually Explicit Internet Material

This study used a person-centered approach to examine whether different developmental trajectories of boys’ and girls’ use of sexually explicit Internet material (SEIM) exist, which factors predict these trajectories, and whether sexual behavior develops differently for adolescents in these trajectories. A combination of latent class growth analysis on SEIM use and latent growth curve analysis on sexual behavior was used on four-wave longitudinal data of 787 eighth through tenth grade Dutch adolescents. Among boys, four SEIM use trajectories were identified, which were labeled Nonuse/Infrequent Use, Strongly Increasing Use, Occasional Use, and Decreasing Use. Among girls, a large Stable Nonuse/Infrequent Use and smaller Strongly Increasing Use and Stable Occasional Use trajectories were distinguished. Higher initial levels and/or stronger increases in SEIM use were predicted by demographic, social contextual, personal, and media use characteristics, including a stronger sexual interest, a higher degree of perceived realism regarding sexualized Internet content, and more permissive sexual attitudes. Moreover, initial levels of and, to some extent, developmental changes in sexual behavior varied for boys and girls in the different SEIM use trajectories. Whereas some adolescents showed concurrent low levels, or parallel strong increases in SEIM use and sexual behavior, a subgroup of boys decreased their SEIM use while increasing their sexual behavior.     

Let's Call it Quits: Break‐Even Effects in the Decision to Stop Taking Risks

“Chasing” behavior, whereby individuals, driven by a desire to break even, continue a risky activity (RA) despite incurring large losses, is a commonly observed phenomenon. We examine whether the desire to break even plays a wider role in decisions to stop engaging in financially motivated RA in a naturalistic setting. We test hypotheses, motivated by this research question, using a large data set: 707,152 transactions of 5,379 individual financial market spread traders between September 2004 and April 2013. The results indicate strong effects of changes in wealth around the break‐even point on the decision to cease an RA. An important mediating factor was the individual's historical long‐term performance. Those with a more profitable trading history were less affected by a fall in cash balance below the break‐even point compared to those who had been less profitable. We observe that break‐even points play an important role in the decision of nonpathological risk takers to stop RAs. It is possible, therefore, that these nonpathological cognitive processes, when occurring in extrema, may result in pathological gambling behavior such as “chasing.” Our data set focuses on RAs in financial markets and, consequently, we discuss the implications for institutions and regulators in the effective management of risk taking in markets. We also suggest that there may be a need to consider carefully the nature and role of “break‐even points” associated with a broader range of nonfinancially‐focused risk‐taking activities, such as smoking and substance abuse.     

The effects of traffic noise on tadpole behavior and development

Urban Ecosystems - Traffic noise is known to negatively affect many wildlife species by interfering with foraging behavior. Frogs often lay their eggs in roadside ditches because they are...     

Play in Mexican‐American mothers and toddlers is frequent,multimodal, and rich in symbolic content

Play offers rich opportunities for toddlers to develop motor, social, cognitive, and language skills, particularly during interactions with adult caregivers who may scaffold toddlers to higher levels of play than toddlers achieve on their own. However, research on play has narrowly focused on children from White, middle‐income backgrounds, leaving a dearth of knowledge about dyadic play in diverse cultural communities. We videorecorded 222 Mexican‐American mothers playing with their 2‐year‐old toddlers with a standard set of toys. Play behaviors were coded as nonsymbolic or symbolic (play type) and as expressed through manual, verbal, or multiple channels (play modality). Play between toddlers and mothers was frequent, high in symbolic content, and toddler play closely corresponded with mother play in type and modality: Toddlers’ nonsymbolic play related to mothers’ nonsymbolic play; toddlers’ symbolic play related to mothers’ symbolic play; toddlers’ manual play related to mothers’ manual play; and toddlers’ multimodal play related to mothers’ multimodal play. Play in Mexican‐American mothers and toddlers is frequent, multimodal, and symbolically rich, offering new directions for future research and practice.     

How do changes in income,employment and health insurance affect family mental health spending?

Using eight two-year panels from the Medical Expenditure Panel Survey data for the period 2004 to 2012, we examine the effect of economic shocks on mental health spending by families with children. Estimating two-part expenditure models within the correlated random effects framework, we find that employment shocks have a greater impact on mental health spending than do income or health insurance shocks. Our estimates reveal that employment gains are associated with a lower likelihood of family mental health services utilization. By contrast employment losses are positively related to an increase in total family mental health. We do not detect a link between economic shocks and mental health spending on behalf of fathers.

     

Kinship Reconsidered: Research on a Neglected Topic

This article reviews the recent history of kinship research, noting the relative neglect of the topic in recent decades. The lack of scholarly and empirical work on kinship has been hampered by both the absence of survey and qualitative research on contemporary kinship practices. The author focuses on what is known and not known about how individual put into practice kinship in the standard, nuclear form of the family. There is surprising in attention to the ceremonial family and, little is know about how families draw boundaries and construct kinship on ritual occasions in the literature. The author concludes by suggesting research strategies for examining both how kinship is constructed and practiced in the United States and in other advanced economies.     

THE EXTENT OF THE MARKET AND INTEGRATION THROUGH FACTOR MARKETS: EVIDENCE FROM WHOLESALE ELECTRICITY

We document the influence of factor markets in determining the extent of the market, appealing to the Mundell hypothesis that trade in goods and factor markets are substitutes. We confirm this influence using the U.S. wholesale market for electric power. Although the Eastern, Western, and Texas regions cannot trade electricity, inputs such as natural gas move freely across these regions. Through a set of price transmission ratios, and a supply model for natural gas, we find regional electricity shocks do propagate across regions. We conclude output markets institutionally in autarky achieve modest degrees of economic integration through factor markets. (JEL C32, L94, Q41)