The present study used multidimensional and person-centered approaches to identify subgroups of adolescents characterized by unique patterns of behavioral, emotional, and cognitive engagement and examined whether adolescent developmental outcomes varied as a function of different combinations of engagement components. Data were collected on 1,025 youths (57% African American, 43% European American; 53% female, 47% male). Five profiles of student engagement in school were identified: Highly Engaged, Moderately Engaged, Minimally Engaged, Emotionally Disengaged, and Cognitively Disengaged. These 5 groups differed in their educational and psychological functioning. The study not only provides empirical evidence supporting the multifaceted nature of school engagement but also demonstrates its utility relative to educational success and mental health. Considering the multiple dimensions of student engagement simultaneously from a person-centered perspective promises a useful approach for addressing sample heterogeneity and understanding different patterns of school engagement and their consequences.

As competition is introduced into the electric power industry, access and pricing policy for transmission will play a pivotal role in shaping future market structure and performance. The externalities associated with the loop flow phenomenon in an electric power network constitute a significant barrier to the formation of efficient markets for electricity and transmission services. In this paper, we present a new approach to the design of an efficient market mechanism for transmission access that resolves these externalities. Under a trading rule that combines the Coasian and the Pigouvian principles to resolution of externalities, property rights are defined so that a competitive market could be established for transmission services and electricity to achieve a social optimum within a power pool. We characterize a dynamic trading process which is Lyapunov stable and always converges to a competitive equilibrium. Finally, we discuss some practical applicability and long-term investment issues.

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Perceived racial discrimination (PRD) has been associated with altered diurnal cortisol rhythms in past cross-sectional research. We investigate whether developmental histories of PRD, assessed prospectively, are associated with adult diurnal cortisol profiles. One-hundred and twelve (N = 50 Black, N = 62 White) adults from the Maryland Adolescent Development in Context Study provided saliva samples in adulthood (at approximately age 32 years) at waking, 30 min after waking, and at bedtime for 7 days. Diurnal cortisol measures were calculated, including waking cortisol levels, diurnal cortisol slopes, the cortisol awakening response (CAR), and average daily cortisol (AUC). These cortisol outcomes were predicted from measures of PRD obtained over a 20-year period beginning when individuals were in 7th grade (approximately age 12). Greater average PRD measured across the 20-year period predicted flatter adult diurnal cortisol slopes for both Black and White adults, and a lower CAR. Greater average PRD also predicted lower waking cortisol for Black, but not White adults. PRD experiences in adolescence accounted for many of these effects. When adolescent and young adult PRD are entered together predicting cortisol outcomes, PRD experiences in adolescence (but not young adulthood) significantly predicted flatter diurnal cortisol slopes for both Black and White adults. Adolescent, but not young adult PRD, also significantly predicted lower waking and lower average cortisol for Black adults. Young adult PRD was, however, a stronger predictor of the CAR, predicting a marginally lower CAR for Whites, and a significantly larger CAR for Blacks. Effects were robust to controlling for covariates including health behaviors, depression, income and parent education levels. PRD experiences interacted with parent education and income to predict aspects of the diurnal cortisol rhythm. Although these results suggest PRD influences on cortisol for both Blacks and Whites, the key findings suggest that the effects are more pervasive for Blacks, affecting multiple aspects of the cortisol diurnal rhythm. In addition, adolescence is a more sensitive developmental period than adulthood for the impacts of PRD on adult stress biology.