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Instrumental variable approach to estimating the scalar-on-function regression model with measurement error with application to energy expenditure assessment in childhood obesity
No full textWearable device technology allows continuous monitoring of biological markers and thereby enables study of time‐dependent relationships. For example, in this paper, we are interested in the impact of daily energy expenditure over a period of time on subsequent progression toward obesity among children. Data from these devices appear as either sparsely or densely observed functional data and methods of functional regression are often used for their statistical analyses. We study the scalar‐on‐function regression model with imprecisely measured values of the predictor function. In this setting, we have a scalar‐valued response and a function‐valued covariate that are both collected at a single time period. We propose a generalized method of moments‐based approach for estimation, while an instrumental variable belonging in the same time space as the imprecisely measured covariate is used for model identification. Additionally, no distributional assumptions regarding the measurement errors are assumed, while complex covariance structures are allowed for the measurement errors in the implementation of our proposed methods. We demonstrate that our proposed estimator is L2 consistent and enjoys the optimal rate of convergence for univariate nonparametric functions. In a simulation study, we illustrate that ignoring measurement error leads to biased estimations of the functional coefficient. The simulation studies also confirm our ability to consistently estimate the function‐valued coefficient when compared to approaches that ignore potential measurement errors. Our proposed methods are applied to our motivating example to assess the impact of baseline levels of energy expenditure on body mass index among elementary school–aged children
A Genetic Screen Using the Drosophila melanogaster TRiP RNAi Collection To Identify Metabolic Enzymes Required for Eye Development
No full textThe metabolic enzymes that compose glycolysis, the citric acid cycle, and other pathways within central carbon metabolism have emerged as key regulators of animal development. These enzymes not only generate the energy and biosynthetic precursors required to support cell proliferation and differentiation, but also moonlight as regulators of transcription, translation, and signal transduction. Many of the genes associated with animal metabolism, however, have never been analyzed in a developmental context, thus highlighting how little is known about the intersection of metabolism and development. Here we address this deficiency by using the Drosophila TRiP RNAi collection to disrupt the expression of over 1,100 metabolism-associated genes within cells of the eye imaginal disc. Our screen not only confirmed previous observations that oxidative phosphorylation serves a critical role in the developing eye, but also implicated a host of other metabolic enzymes in the growth and differentiation of this organ. Notably, our analysis revealed a requirement for glutamine and glutamate metabolic processes in eye development, thereby revealing a role of these amino acids in promoting Drosophila tissue growth. Overall, our analysis highlights how the Drosophila eye can serve as a powerful tool for dissecting the relationship between development and metabolism
Which adolescent factors predict alcohol misuse in young adulthood? A co-twin comparisons study
No full textBackground and aims: Research on adolescent predictors of later alcohol misuse is typically conducted on samples of singletons, and associations may be confounded by between‐family differences. To address potential confounding, we applied a co‐twin comparison design to evaluate whether differences between co‐twins in a wide array of adolescent risk factors predicted differences in young adult alcohol misuse. Design: Longitudinal study in which associations between characteristics of the sample as adolescents were used to predict young adult alcohol misuse in individual‐level analyses and co‐twin comparisons. Setting: Finland. Participants: A total of 3402 individuals (1435 complete twin pairs; 36% monozygotic; 57% female) from the FinnTwin12 study. Measurements: The young adult alcohol misuse outcome was a composite score of alcohol use and intoxication frequency. Adolescent predictors included factor scores representing academic performance, substance use, externalizing problems, internalizing problems, peer environment, physical health and relationship with parents; and single measures tapping alcohol expectancies, life events and pubertal development. Findings: In individual‐level analyses, individuals with higher adolescent substance use, externalizing problems, time with friends, peer deviance, sports involvement, sleeping difficulties, parental discipline, positive alcohol expectancies and difficulty of life events reported higher alcohol misuse in young adulthood (Ps < 0.019, R = 0.0003–0.0310%). Conversely, those with higher adolescent internalizing problems, parent–child relationship quality and time with parents reported lower alcohol misuse (Ps < 0021, R = 0.0018–0.0093%). The associations with adolescent substance use and alcohol expectancies remained significant in co‐twin comparisons (Ps < 0.049, R = 0.0019–0.0314%). Further, academic performance emerged as a significant predictor, such that individuals with higher grades compared with their co‐twin reported higher young adult alcohol misuse (Ps < 0.029, R = 0.0449–0.0533%). Conclusions: Adolescent substance use, positive alcohol expectancies and higher academic performance appear to be robust predictors of later alcohol misuse
Experiencing sexual harassment by males and associated substance use & poor mental health outcomes among adolescent girls in the US
No full textPurpose: Among a sample of adolescent girls, we assessed: 1) prevalence of sexual harassment by type, place of occurrence, and perpetrators; 2) association with substance use and poor mental health outcomes; and 3) the proportion of girls experiencing sexual harassment in more than one place and relation to study outcomes. Methods: We collected survey data from 159 sexually active girls (aged 15–19 years) recruited from an urban health clinic in Southern California. We used multivariable regression models to assess associations between sexual harassment in the past 6 months and the following outcomes: 1) substance use in past 30 days (alcohol use, binge drinking, and marijuana use, respectively); 2) other drug use ever; and 3) feelings of depression and anxiety, respectively, in past 30 days. Results: Almost two-thirds of girls (65.4%) reported experiencing sexual harassment in the past 6 months. Among those reporting recent harassment (n = 104), the abuse most frequently occurred in public spaces (on public transport [50.5%], at school [42.7%], and in their neighborhoods [39.8%]) and most often in the form of sexual comments, jokes, or gestures (57.2%), although 12.6% were “touched, grabbed, or pinched in a sexual way.” The vast majority (82.7%) did not know the perpetrators (82.7%). Experiences of sexual harassment in the past 6 months were significantly associated with alcohol use (odds ratio [OR], 4.5; 95% confidence interval [CI], 2.0–10.2), binge drinking (OR, 4.2; 95% CI, 1.8–9.8), and marijuana use (OR, 2.6; 95% CI, 1.2–5.7) in the past 30 days; other drug use ever (OR, 5.4; 95% CI, 1.8–16.4); and feelings of depression (OR: 2.7; 95%CI: 1.3–5.5) and anxiety (OR: 2.6; 95%CI: 1.2–5.5) in the past 30 days. Just over half (55.3%) reported sexual harassment in more than one place, which was also associated with poor substance use and mental health outcomes. Conclusions: Findings suggest that sexual harassment experiences are pervasive, occur in girls' immediate and everyday environments, and are associated with girls’ substance use and adverse mental health outcomes
Intergroup variation in oestrogenic plant consumption by black-and-white colobus monkeys
No full textEndocrine-active phytochemicals (EAPs) are a potentially important component of the tropical plant foods of many primate species due to their interactions with hormones and potential effects on reproduction and behavior. If EAPs, such as phytoestrogens, do significantly affect primate biology in their natural environment, then variation in exposure to these chemicals should relate to variation in physiological or behavioral outcomes. Therefore, we quantified the diet of eight black-and-white colobus monkey groups (Colobus guereza) living in Kibale National Park, Uganda, for one year and analyzed their plant foods for estrogenic activity using transient transfection assays. The percent of diet from these estrogenic plant items varied across groups from 1.24% (± SD 1.65) to 5.85% (± SD 4.51), however this variation was not statistically significant given seasonal variation within the same group. Additionally, grooming was not correlated with phytoestrogen consumption, except for in one group. This lack of an effect was likely due to the low levels of consumption of estrogenic plants compared to previous studies that did document a grooming effect. Examining intergroup variation in other primate species that consume a greater quantity of EAPs in their diet will provide further insight into physiological and behavioral effects of consumption on primate ecology
Constraining the initial conditions and temperature dependent viscosity with three-particle correlations in Au+Au collisions
No full textWe present three-particle mixed-harmonic correlations for harmonics =1−3 for charged particles in = 200 GeV Au+Au collisions at RHIC. These measurements provide information on the three-dimensional structure of the initial collision zone and are important for constraining models of a subsequent low-viscosity quark-gluon plasma expansion phase. We investigate correlations between the first, second and third harmonics predicted as a consequence of fluctuations in the initial state. The dependence of the correlations on the pseudorapidity separation between particles show hints of a breaking of longitudinal invariance. We compare our results to a number of state-of-the art hydrodynamic calculations with different initial states and temperature dependent viscosities. These measurements provide important steps towards constraining the temperature dependent transport and the longitudinal structure of the initial state at RHIC
Sex specific associations in genome wide association analysis of renal cell carcinoma.
No full textRenal cell carcinoma (RCC) has an undisputed genetic component and a stable 2:1 male to female sex ratio in its incidence across populations, suggesting possible sexual dimorphism in its genetic susceptibility. We conducted the first sex-specific genome-wide association analysis of RCC for men (3227 cases, 4916 controls) and women (1992 cases, 3095 controls) of European ancestry from two RCC genome-wide scans and replicated the top findings using an additional series of men (2261 cases, 5852 controls) and women (1399 cases, 1575 controls) from two independent cohorts of European origin. Our study confirmed sex-specific associations for two known RCC risk loci at 14q24.2 (DPF3) and 2p21(EPAS1). We also identified two additional suggestive male-specific loci at 6q24.3 (SAMD5, male odds ratio (OR) = 0.83 [95% CI = 0.78-0.89], P = 1.71 × 10 compared with female odds ratio (OR) = 0.98 [95% CI = 0.90–1.07], P = 0.68) and 12q23.3 (intergenic, OR = 0.75 [95% CI = 0.68-0.83], P = 1.59 × 10 compared with OR = 0.93 [95% CI = 0.82–1.06], P = 0.21) that attained genome-wide significance in the joint meta-analysis. Herein, we provide evidence of sex-specific associations in RCC genetic susceptibility and advocate the necessity of larger genetic and genomic studies to unravel the endogenous causes of sex bias in sexually dimorphic traits and diseases like RCC
