Human computation is a computing approach that draws upon human cognitive abilities to solve computational tasks for which there are so far no satisfactory fully automated solutions even when using the most advanced computing technologies available. Human computation for citizen science projects consists in designing systems that allow large crowds of volunteers to contribute to scientific research by executing human computation tasks. Examples of successful projects are Galaxy Zoo and FoldIt. A key feature of this kind of project is its capacity to engage volunteers. An important requirement for the proposal and evaluation of new engagement strategies is having a clear understanding of the typical engagement of the volunteers; however, even though several projects of this kind have already been completed, little is known about this issue. In this paper, we investigate the engagement pattern of the volunteers in their interactions in human computation for citizen science projects, how they differ among themselves in terms of engagement, and how those volunteer engagement features should be taken into account for establishing the engagement encouragement strategies that should be brought into play in a given project. To this end, we define four quantitative engagement metrics to measure different aspects of volunteer engagement, and use data mining algorithms to identify the different volunteer profiles in terms of the engagement metrics. Our study is based on data collected from two projects: Galaxy Zoo and The Milky Way Project. The results show that the volunteers in such projects can be grouped into five distinct engagement profiles that we label as follows: hardworking, spasmodic, persistent, lasting, and moderate. The analysis of these profiles provides a deeper understanding of the nature of volunteers' engagement in human computation for citizen science projects.
 One of the most challenging problems facing builders and facilitators of community networks is to create and sustain social engagement among members. In this paper, we investigate the drivers of social engagement in a community network through the analysis of three data sources: activity logs, a member survey, and the content analysis of the conversation archives. We describe three important ways to encourage and support social engagement in online communities: through system design elements such as conversation channeling and event notification, by various selection criteria for community members, and through facilitation of specific kinds of discussion topics. Online communities are among the most popular destinations on the Internet, but not all online communities are equally successful. For every flourishing Facebook, there is a moribund Friendster--not to mention the scores of smaller social networking sites that never attracted enough members to be viable. This book offers lessons from theory and empirical research in the social sciences that can help improve the design of online communities. The social sciences can tell us much about how to make online communities thrive, offering theories of individual motivation and human behavior that, properly interpreted, can inform particular design choices for online communities. The authors draw on the literature in psychology, economics, and other social sciences, as well as their own research, translating general findings into useful design claims. They explain, for example, how to encourage information contributions based on the theory of public goods, and how to build members' commitment based on theories of interpersonal bond formation. For each design claim, they offer supporting evidence from theory, experiments, or observational studies.The book focuses on five high-level design challenges: starting a new community, attracting new members, encouraging commitment, encouraging contribution, and regulating misbehavior and conflict. By organizing their presentation around these fundamental design features, the authors encourage practitioners to consider alternatives rather than simply adapting a feature seen on other sites. Abstract Objectives Engagement at work has emerged as a potentially important employee performance and organizational management topic, however, the definition and measurement of engagement at work, and more specifically, nurse engagement, is poorly understood. The objective of this paper is to examine the current state of knowledge about engagement at work through a review of the literature. This review highlights the four lines of engagement research and focuses on the determinants and consequences of engagement at work. Methodological issues, as identified in the current research, and recommendations for future nurse-based engagement research are provided. Design A systematic review of the business, organizational psychology, and health sciences and health administration literature about engagement at work (1990–2007) was performed. Data sources The electronic databases for Health Sciences and Health Administration (CINAHL, MEDLINE), Business (ABI INFORM), and Psychology (PsycINFO) were systematically searched. Review methods Due to the limited amount of research that has examined engagement among the nursing workforce, published research that included varying employee types were included in this review. The selection criteria for this review include those studies that were: (1) written in English and (2) examined engagement at work in employee populations of any type within any work setting. Results The literature review identified four distinct lines of research that has focused on engagement within the employee work role. Of the 32 engagement-based articles referenced in this paper, a sample of 20 studies report on the examination of antecedents and or consequences of engagement at work among varying employee types and work settings. Key findings suggest organizational factors versus individual contributors significantly impact engagement at work. A common implication in this body of research was that of the performance-based impact. Conclusions The study of nurses' work engagement and its relationship to nurses' organizational behavior, including work performance and healthcare organizational outcomes can be achieved by first building upon a conceptually consistent definition and measurement of work engagement. Future research is needed to provide nurse leaders with a better understanding of how nurse work engagement impacts organizational outcomes, including quality of care indicators. Abstract: This article focuses on the importance of social engagement and the behavioral and neurophysiological mechanisms that allow individuals to reduce psychological and physical distance. A model of social engagement derived from the Polyvagal Theory is presented. The model emphasizes phylogeny as an organizing principle and includes the following points: (1) there are well-defined neural circuits to support social engagement behaviors and the defensive strategies of fight, flight, and freeze; (2) these neural circuits form a phylogenetically organized hierarchy; (3) without being dependent on conscious awareness, the nervous system evaluates risk in the environment and regulates the expression of adaptive behavior to match the neuroception of a safe, dangerous, or life-threatening environment; (4) social engagement behaviors and the benefits of the physiological states associated with social support require a neuroception of safety; (5) social behaviors associated with nursing, reproduction, and the formation of strong pair bonds require immobilization without fear; and (6) immobilization without fear is mediated by a co-opting of the neural circuit regulating defensive freezing behaviors through the involvement of oxytocin, a neuropeptide in mammals involved in the formation of social bonds. The model provides a phylogenetic interpretation of the neural mechanisms mediating the behavioral and physiological features associated with stress and several psychiatric disorders. The article analyzes the concept of student cognitive engagement, and the manner in which classroom instruction may develop self‐regulated learners. Since theory and research on academic motivation, to date only vaguely define the role of learning processes, and since studies of learning strategies rarely assess motivational outcomes, our analysis integrates these two streams of literature. We also identify specific features of instruction and discuss how they might influence the complex of student interpretive processes focal to classroom learning and motivation. Measurement issues and research strategies peculiar to the investigation of cognitive engagement are addressed.