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.     

Puberty in the Last 25 Years: A Retrospective Bibliometric Analysis

Puberty research has been highly productive in the past few decades and is gaining momentum. We conducted an analysis of bibliographic data, including titles, abstracts, keywords, indexing terms, and citation data to assess the sheer numbers, audience and reach, publication types, and impact of puberty‐related publications. Findings suggest that puberty‐related publications are increasing in sheer numbers, and have reach in many fields as befits an interdisciplinary science. Puberty‐related publications typically have higher impact in terms of citations than the journal averages, among the journals that published the most studies on puberty. Limitations of the field and recommendations for researchers to improve the impact and reach of puberty‐related publications (e.g., clear conclusions in abstracts, highlighting the importance of puberty) are discussed.     

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...     

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)     

Resolving complex community problems: Applying collective leadership and Kotter's change model to wicked problems within social system networks

How does collective leadership within social networks resolve chronic and complex problems common to communities? Unfortunately, sometimes it does not, but when it does, the outcome may be truly extraordinary. We use a case study approach to explain how one Midwest community within the USA applied collective leadership within a community network to reduce teen births. It took ten years of what many identified as provocative media campaigns and comprehensive sex education programs to reduce teen births by 65%, significantly exceeding the stated goal. Using Kotter's change model as a backdrop, powerful strategies and provocative creativity reveal courageous leadership within a social network of diverse people and organizations focused on improving the social well being of their community.     

A Hitchhiker's Guide to caring for an older person before and during coronavirus‐19

Coronavirus‐19 (COVID‐19) has reconfigured working lives with astonishing velocity. Older people have suffered the worst effects of the pandemic, with governments marginalizing or overlooking their needs. Women perform the majority of care for older people, often compromising their working lives and health. Yet in academic articles their voices are often filtered or aggregated in quantitative studies. Based on a weave of personal experiences and secondary research, the article traces a path through UK forms of care and shows how the inadequate response to COVID‐19 stemmed from existing policies embedded in health and social care. COVID‐19 has severed important informal care work, rendering the vulnerable yet more exposed and carers anxious and bereft. Longitudinal research capturing the trajectory of care from the perspective of older people and their carers would lead to improved support hence gender equality.