Activities, engagement, and emotion in after-school programs (and elsewhere)

Experiences that are deeply engaging and enjoyable, engender full concentration, and present a balance between challenge and skill promote children's development. This chapter describes a study that sought to identify the kinds of settings and activities that foster engagement and, by extension, positive youth development. The after-school experiences of 191 ethnically diverse youth living in three states, some of whom participated in after-school programs and some of whom did not, were studied. Youth were equipped with logbooks and watches that were programmed to signal at random times. When signaled, youth recorded their location, social partners, activity, and feelings. The study found pervasive differences in the experiences at programs and elsewhere. Youth spent more time in academic and arts enrichment, organized sports and physical activities, community service, and homework at programs versus elsewhere, and they spent less time eating and watching TV at programs. They also reported higher levels of motivation, engagement, and positive affect at programs. At the same time, there were few differences in activities, emotions, effort, or motivation of program participants and nonparticipants when both groups were elsewhere. The similarities in these experiences while elsewhere suggest that the program context, not differences in youth characteristics or interests, was responsible for the feelings of engagement that were reported at programs.     

Prevention validation and accounting platform: a framework for establishing accountability and performance measures of substance abuse prevention programs

The field of substance abuse prevention has neither an overarching conceptual framework nor a set of shared terminologies for establishing the accountability and performance outcome measures of substance abuse prevention services rendered. Hence, there is a wide gap between what we currently have as data on one hand and information that are required to meet the performance goals and accountability measures set by the Government Performance and Results Act of 1993 on the other. The task before us is: How can we establish the accountability and performance measures of substance abuse prevention programs and transform the field of prevention into prevention science? The intent of this volume is to serve that purpose and accelerate the processes of this transformation by identifying the requisite components of the transformation (i.e., theory, methodology, convention on terms, and data) and by introducing an open forum called, Prevention Validation and Accounting (PREVA) Platform. The entire PREVA Platform (for short, the Platform) is designed as an analytic framework, which is formulated by a collectivity of common concepts, terminologies, accounting units, protocols for counting the units, data elements, and operationalizations of various constructs, and other summary measures intended to bring about an efficient and effective measurement of process input, program capacity, process output, performance outcome, and societal impact of substance abuse prevention programs. The measurement units and summary data elements are designed to be measured across time and across jurisdictions, i.e., from local to regional to state to national levels. In the Platform, the process input is captured by two dimensions of time and capital. Time is conceptualized in terms of service delivery time and time spent for research and development. Capital is measured by the monies expended for the delivery of program activities during a fiscal or reporting period. Program capacity is captured by fourteen measurement units, tapping into the dimensions of staff resources and community assets. Staff resources are, in turn, operationalized in terms of staff size, staff certification status, staff turnover rate, and the accreditation status of a provider agency. Community assets are operationalized by the number of community centers accessible to the funded agency, number of formalized teams or antidrug coalitions active in the catchment area, and other social/human services providers with whom the prevention agency has formalized networks. The totality of process output from all sources of program activities is reduced to eighteen classes of measures. These are operationalized by thirty-three summary measures. Some of these include: total count of events facilitated; total number of clients served; average number of clients served per event; clients served by single and multiple program sessions; classification of target population in terms of the severity of risk as defined by the Institute of Medicine; age groups and race/ethnicity of clients served; number of program participants retained by recurring programs; number of clients who have completed the program; penetration rates to the target population; client attrition rates; average referral rates per provider per time interval; referral success rates; and so on. All process output measures specified in the Platform are derived from two broad classes of events classified as either products or services. The collectivity of these measures is expected to present a cost-effective, parsimonious, yet comprehensive picture of the entire spectrum of the process output, i.e., "what came out of the program as program activities". For the measurement of performance outcomes, two types of data are incorporated into the Platform: outcome data from individuals and the behavior (or performance) of social indicators from aggregated data bases. Individual data are used to evaluate the outcome of substance abuse programs     

A Polynomial Time Approximation Scheme for the Problem of Interconnecting Highways

The objective of the Interconnecting Highways problem is to construct roads of minimum total length to interconnect n given highways under the constraint that the roads can intersect each highway only at one point in a designated interval which is a line segment. We present a polynomial time approximation scheme for this problem by applying Arora's framework (Arora, 1998; also available from http:www.cs.princeton.edu/~arora). For every fixed c > 1 and given any n line segments in the plane, a randomized version of the scheme finds a -approximation to the optimal cost in O(n ^O(c)log(n) time.     

Can what is right with sociology fix what is wrong with sociology? A view from the “Come-back” generation

Sociology’s fragility, in its latest manifestation, is not a result of controversies over method or theory. The challenge is far more serious than those, for it involves the question of whether the subjects of this new science—human beings themselves have any distinctive features that require a distinctive science to be understood.     

Robustly Collusion‐Proof Implementation

A contract with multiple agents may be susceptible to collusion. We show that agents' collusion imposes no cost in a large class of circumstances with risk neutral agents, including both uncorrelated and correlated types. In those circumstances, any payoff the principal can attain in the absence of collusion, including the second‐best level, can be attained in the presence of collusion in a way robust to many aspects of collusion behavior. The collusion‐proof implementation generalizes to a setting in which only a subset of agents may collude, provided that noncollusive agents' incentives can be protected via an ex post incentive compatible and ex post individually rational mechanism. Our collusion‐proof implementation also sheds light on the extent to which hierarchical delegation of contracts can optimally respond to collusion.     

Alcohol Consumption Decisions in Korea

Data from the 1996 Korean Household Panel Study and a double-hurdle model were used to analyze alcohol consumption decisions in Korea. The Korean most likely to consume alcoholic beverages is a young male, and a college graduate. Among those who drink, being older, male, self-employed, or a farm or fishery worker were positively associated, and higher education levels were negatively associated with consumption level. The findings for gender and education were generally similar to those of studies using U.S. or Canadian data on alcohol consumption. The role of household level economic factors, family composition, and residence in alcohol consumption decisions appears to differ across cultures, however.     

Bayesian analysis of paired survival data using a bivariate exponential distribution

We consider a Bayesian analysis method of paired survival data using a bivariate exponential model proposed by Moran (1967, Biometrika 54:385–394). Important features of Moran’s model include that the marginal distributions are exponential and the range of the correlation coefficient is between 0 and 1. These contrast with the popular exponential model with gamma frailty. Despite these nice properties, statistical analysis with Moran’s model has been hampered by lack of a closed form likelihood function. In this paper, we introduce a latent variable to circumvent the difficulty in the Bayesian computation. We also consider a model checking procedure using the predictive Bayesian P-value.     

Bayesian dynamic models for survival data with a cure fraction

In this paper, we propose a new class of semi-parametric cure rate models. Specifically, we construct dynamic models for piecewise hazard functions over a finite partition of the time axis. Allowing the size of partition and the levels of baseline hazard to be random, our proposed models provide a great flexibility in controlling the degree of parametricity in the right tail of the survival distribution and the amount of correlations among the log-baseline hazard levels. Several properties of the proposed models are derived, and propriety of the implied posteriors with improper noninformative priors for regression coefficients based on the proposed models is established for the fixed partition of the time axis. In addition, an efficient reversible jump computational algorithm is developed for carrying out posterior computation. A real data set from a melanoma clinical trial is analyzed in detail to further demonstrate the proposed methodology.     

逊志自得与法古创新--朝鲜王朝后期实学性的两条思惟之路

朝鲜王朝后期实学研究的两大流派可以说是星湖学派与北学派.从思维的论法来考察这两大流派的共同与不同点,并通过这些考察从宏观的角度重新探讨实学的性格.星湖学派的李瀷主唱逊志自得说法来做为经学的指针或者思维的论法,而北学派的朴趾源提出法古与创新做为作文的指针或者思维的论法.逊志自得的论法在形式上设定了他者与主体间的紧张,而实际上含蓄着对主体的自觉与对它的志向.北学派的法古创新论法虽然在形式上设定着上古与现在间的紧张,但实际上还含蓄着对现在的觉醒与信赖.     

What drives successful social networking services? A comparative analysis of user acceptance of Facebook and Twitter

This study identifies perceived mobility, security, connectedness, system and service quality, usefulness, attitude, and flow experience as key motivational factors for using social networking services (SNSs), and develops a theoretical model that explicates the process in which users adopt Facebook and Twitter by integrating these factors with the technology acceptance model (TAM). While results of structural equation modeling (SEM) on the collected data (N = 2,214) verified the validity and reliability of the research model, Facebook and Twitter users were found to emphasize different motivational factors when deciding to use SNSs. The implications of notable findings and directions for future studies are discussed.