Variation in Dual Citizenship Policies in the Countries of the EU

While the concept of citizenship has received considerable scholarly attention in recent years, few studies focus on the increasingly prevalent reality of dual citizenship, or full membership – with its respective rights, privileges, and obligations – in two different countries. The main objective of this article is to conceptualize, measure, and classify variation in dual citizenship in the countries of the European Union. I start by recounting the historical opposition to dual citizenship and by describing its emergence in recent decades. I then develop a “Citizenshi Policy Index” that accounts for some of the intricacies associated with citizenship policies in general and dual citizenship policies in particular. I go on to apply these measures to the fifteen “older” EU countries in both the 1980s and the contemporary period – thus allowing for an analsis of the changes that have taken place over the past two decades members. Overall, the findings point to surprisingly resilient national differences that stand out in contrast to the EU's institutional “harmonization” in so many other areas.     

A novel approach to estimation of the time to biomarker threshold: applications to HIV

In longitudinal studies of biomarkers, an outcome of interest is the time at which a biomarker reaches a particular threshold. The CD4 count is a widely used marker of human immunodeficiency virus progression. Because of the inherent variability of this marker, a single CD4 count below a relevant threshold should be interpreted with caution. Several studies have applied persistence criteria, designating the outcome as the time to the occurrence of two consecutive measurements less than the threshold. In this paper, we propose a method to estimate the time to attainment of two consecutive CD4 counts less than a meaningful threshold, which takes into account the patient‐specific trajectory and measurement error. An expression for the expected time to threshold is presented, which is a function of the fixed effects, random effects and residual variance. We present an application to human immunodeficiency virus‐positive individuals from a seroprevalent cohort in Durban, South Africa. Two thresholds are examined, and 95% bootstrap confidence intervals are presented for the estimated time to threshold. Sensitivity analysis revealed that results are robust to truncation of the series and variation in the number of visits considered for most patients. Caution should be exercised when interpreting the estimated times for patients who exhibit very slow rates of decline and patients who have less than three measurements. We also discuss the relevance of the methodology to the study of other diseases and present such applications. We demonstrate that the method proposed is computationally efficient and offers more flexibility than existing frameworks. Copyright © 2016 John Wiley & Sons, Ltd.     

Efficient volatility estimation in a two-factor model

We statistically analyze a multivariate Heath-Jarrow-Morton diffusion model with stochastic volatility. The volatility process of the first factor is left totally unspecified while the volatility of the second factor is the product of an unknown process and an exponential function of time to maturity. This exponential term includes some real parameter measuring the rate of increase of the second factor as time goes to maturity. From historical data, we efficiently estimate the time to maturity parameter in the sense of constructing an estimator that achieves an optimal information bound in a semiparametric setting. We also nonparametrically identify the paths of the volatility processes and achieve minimax bounds. We address the problem of degeneracy that occurs when the dimension of the process is greater than two, and give in particular optimal limit theorems under suitable regularity assumptions on the drift process. We consistently analyze the numerical behavior of our estimators on simulated and real datasets of prices of forward contracts on electricity markets.     

Long-term safety of stimulant medications used to treat children with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a common mental health condition that affects children, adolescents, and adults. Because it is a chronic condition and typically requires effective treatment for several years or more, information on the benefits and risks of long-term pharmacotherapy for ADHD is vital to clinicians. This article reviews the emerging literature on the safety of long-term stimulant medications in ADHD-the most commonly prescribed medications for this condition. Common side effects, including cardiovascular effects, growth effects, and tics, are discussed, as well as treatment of children younger than age 6 and evidence of carcinogenic and reproductive effects.     

Free trade and cheap theatre: sources of politics for the nineteenth-century London poor

The very poor and unskilled workers of mid-nineteenth-century London – often termed the ‘casual poor’ due to their irregularity of employment – have been generally portrayed as entirely apolitical, and to have exhibited purely mob responses to the issues of the day. This article suggests that we have not properly understood or ‘read’ the evidence we have of the attitudes towards politics of these people, and that we have assessed their actions purely within the framework of our own understandings. In particular, their views about Chartism, the major working-class political movement of the period, have been a key to how they have been perceived. But our understanding of these views has been distorted by what appeared to be their lack of knowledge of the ‘real’ aims of the movement. Instead, if we look at other types of evidence, such as from the theatre, we can find clues as to how their understandings of such conflicts may simply have been different, and so be able to explain in much more rational terms the actions and beliefs of this historically inarticulate group.     

Why do larger families reduce parental investments in child quality, but not child quality per se?

Becker’s Quantity–Quality model (Becker in Demographic and economic change in developed countries, Princeton University Press, Princeton, pp 209–240, 1960; Becker and Lewis in J Polit Econ 81(2): S279–S288, 1973; Becker and Tomes in J Polit Econ 84(4): S143–S162, 1976) suggests a trade-off between family size and parental investments in children. To date, only Cáceras-Delpiano (J Hum Resour 41(4): 738–754, 2006) tests this theory by considering private school enrolment. This study extends this work by using a unique data set containing a broader range of parental investments that are arguably linked to parental intentions for producing higher quality children, such as overall and non-sectarian private school enrolment, the number of computers in the home per child, and saving for the child’s education. Both studies find that fertility reduces parental investments. However, the literature generally finds that fertility has no impact on child outcomes. The study offers three potential explanations for this ‘puzzle’.     

Do people respond to low probability risks? Evidence from tornado risk and manufactured homes

Whether people perceive and respond to low-probability natural hazards is a research question of considerable policy relevance. We obtain evidence by considering the response of housing choice to tornado risk for manufactured homes. The vulnerability of manufactured housing, combined with its growing share of the U.S. housing market, has led to proposed mandates for community shelters in mobile home parks. Expected utility theory, however, predicts that households should account for tornado risk in their housing choice. We test for an effect of tornado risk on manufactured housing demand using cross-sectional state data, as well as counties in three tornado prone states. We find that people do respond to tornado risk; our estimates indicate that each expected annual state tornado death per million residents reduces demand for manufactured homes by about 3%. The estimated quantity effect is consistent with the market studies of the price elasticity of manufactured homes.