A novel implementation of local fractal dimension to calculate vessel density and FAZ area was demonstrated. Age did not impact vessel density but sectoral analyses showed greater vessel density in the inferior zone.

Aims 1) To evaluate the role of pre-existing weakness in working memory ability (WM) as a risk factor for early alcohol use as mediated by different forms of impulsivity. 2) To assess the adverse effects of progressive alcohol use on variations in WM over time. Design, Setting and Participants A community sample of 358 adolescents [48% males, Meanage(baseline) = 11.4± 0.87 years] from a longitudinal cohort design, assessed annually over four consecutive years with less than 6% attrition. Measurements Repeated assessments were conducted for the following key variables: WM (based on performance on four separate tasks), frequency of alcohol use (AU), and three forms of impulsivity, namely sensation seeking (SS), acting-without-thinking (AWT) and delay discounting (DD). Latent growth curve modeling procedures were used to identify individual trajectories of change for all key variables. Findings Weakness in WM (at baseline) significantly predicted both concurrent alcohol use and increased frequency of use over the four waves (p <.05). This effect was entirely mediated by two forms of impulsivity, AWT and DD, both of which were characterized by underlying weakness in WM. No individual variation was observed in the slopes of WM, which suggests that individual variations in alcohol use were not associated with changes in WM in our early adolescent sample. Conclusions Early adolescent alcohol use may be a consequence of (pre-existing) weaknesses in working memory (WM) rather than a cause of it. Efforts to reduce early alcohol use should consider the distinct roles of different impulsivity dimensions, in addition to WM, as potential targets of intervention.

With many adolescents using the internet to communicate with their peers, online harassment is on the rise among youth. The purpose of this study was to understand how parental monitoring and strategies parents use to regulate children's internet use (i.e., internet restriction) can help reduce online harassment among adolescents. Online survey data were collected from a nationally representative sample of parents and their 12-17 year old adolescents (n = 629; 49 % female). Structural equation modeling was used to test direct and indirect effects of parental monitoring and internet restriction on being a victim of online harassment. Potential mediators included adolescents' frequency of use of social networking websites, time spent on computers outside of school, and internet access in the adolescent's bedroom. Age and gender differences were also explored. Adolescents' reports of parental monitoring and efforts to regulate specific forms of internet use were associated with reduced rates of online harassment. Specifically, the effect of parental monitoring was largely direct and 26 times greater than parental internet restriction. The latter was associated with lower rates of harassment only indirectly by limiting internet access in the adolescent's bedroom. These effects operated similarly for younger and older adolescents and for males and females. Adolescents' perceptions of parental monitoring and awareness can be protective against online harassment. Specific restriction strategies such as regulating internet time and content can also help reduce the risk of online harassment.

Although deficits in working memory ability have been implicated in suboptimal decision making and risk taking among adolescents, its influence on early sexual initiation has so far not been examined. Analyzing 2 waves of panel data from a community sample of adolescents (N = 347; Mean age [baseline] = 13.4 years), assessed 1 year apart, the present study tested the hypothesis that weak working memory ability predicts early sexual initiation and explored whether this relationship is mediated by sensation seeking and 2 forms of impulsivity, namely acting-withoutthinking and temporal discounting. The 2 forms of impulsivity were expected to be positively associated with early sexual initiation, whereas sensation seeking was hypothesized to be unrelated or to have a protective influence, due to its positive association with working memory. Results obtained from structural equation modeling procedures supported these predictions and in addition showed that the effects of 3 prominent risk factors (Black racial identity, low socioeconomic background, and early pubertal maturation) on early sexual initiation were entirely mediated by working memory and impulsivity. The findings are discussed in regard to their implications for preventing early sexual onset among adolescents. Keywordsearly sexual debut; working memory; impulsivity; sensation seeking; delay discounting Adolescence has long been recognized as a period of heightened vulnerability to adverse health outcomes. Relative to both children and adults, adolescent rates of morbidity and mortality are disturbingly high and are linked to suboptimal decisions to engage in healthcompromising behaviors (Arnett, 1992;Dahl, 2004). Contrary to the popular notion that teenagers make light of the risks associated with their behaviors, research finds that adolescents are not only sensitive to the risks but also tend to overestimate them (Reyna & Farley, 2006). Nevertheless, whether all adolescents use these risk appraisals in an adaptive manner when making decisions regarding health-compromising behaviors, such as early sexual initiation, remains open to question.Adolescence is the developmental period when romantic and sexual exploration begins (Craver, Joyner, & Udry, 2003;B. C. Miller & Benson, 1999), with the initiation of vaginal intercourse becoming common during mid-to late adolescence (ages 16-19) Mosher, 2006). Although sexual activity among adolescents is often unprotected, sexual initiation at younger ages is found to be associated with greater involvement in risky sexual behaviors, including inconsistent condom use (Manlove, Ryan, & Franzetta, 2007;Manning, Longmore, & Giordano, 2000) and involvement with multiple sexual partners (O'Donnell, O'Donnell, & Stueve, 2001) that can increase the risk of unintended pregnancies and sexually transmitted infections (Cates, Herndon, Schulz, & Darroch, 2004;Coker et al., 1994;Greenberg, Magder, & Aral, 1992). The high individual and social costs associated with early sexual initiation are nevertheless largely preve...