Thin film electro-osmotic pumps for biomicrofluidic applications

Electro-osmotic flow (EOF) pumps are attractive for fluid manipulation in microfluidic channels. Open channel EOF pumps can produce high pressures and flow rates, and are relatively easy to fabricate on-chip or integrate with other microfluidic or electrical components. An EOF pump design that is conducive to on-chip fabrication consists of multiple small channel arms feeding into a larger flow channel. We have fabricated this type of pump design using a thin film deposition process that avoids wafer bonding. We have evaluated pumps fabricated on both silicon and glass substrates. Consistent flow rate versus electric field were obtained. For the range of 40–400 V, flow rates of 0.19–2.30 μL∕min were measured. Theoretical calculations of pump efficiency were made, as well as calculations of the mechanical power generated by various pump shapes, to investigate design parameters that should improve future pumps.     

Information-Sector Growth in Market and Nonmarket Economies: A Comparative Case Study

The purpose of this study is to identify factors that have led to the emergence of information activities in the global labor force. An analysis of the predominant theoretical perspectives on the development of the information society indicates that a comparison of the development of the information work force in countries that have experienced industrialization under different socioeconomic systems is needed. Finland and Poland are selected as the representatives of a market economy and a centrally planned economy. The results indicate that the information work forces of Finland and Poland have experienced similar patterns of growth over the time period examined. However, the distribution of the work force across different economic sectors differs by socioeconomic system. It is concluded that factors relating to industrialization have played the primary role in the emergence of the information work force and that this emergence may take multiple paths in developing.     

Two approaches to etiology: the debate over smoking and lung cancer in the 1950s

Statisticians R.A. Fisher and Joseph Berkson have become infamous for ending up on the "wrong" side of the debate over the evidence linking smoking and lung cancer during the 1950s, and scholars have speculated about their personal motives in the controversy. But there were many senior biostatisticians and epidemiologists voicing similar concerns about the quality of the evidence at the time, albeit with less inflammatory rhetoric. This debate occurred during a time when epidemiological research methods commonly used today were understood by few and were only just beginning to work their way into public health and medicine. All of the participants in the debate over smoking and lung cancer saw the need for explicit and rigorous standards for evaluating etiological hypotheses, but they held conflicting views about what those standards should be. The differing opinions on the evidence reflected two different models of etiological research--controlled experiment as the crucial, objective test of a causal hypothesis versus inferential judgment based on a diverse body of evidence. This debate has relevance for current epidemiological practice, as tension between these two views still remains.     

Taking initiative and constructing identity: international graduate student spouses’ adjustment and social integration in a rural university town

Nearly one quarter of international graduate students in the USA and Canada are accompanied by their spouse, typically highly educated, professional women. Because they are not students, accompanying spouses’ distinctive needs and experiences are often invisible. This article focuses on an overlooked population of adult learners: accompanying spouses who enrol in English as a Second Language (ESL) courses. Qualitative data are used to explore the social integration and adjustment of 13 accompanying spouses who attended an ESL class in State College, Pennsylvania, a rural university town in the USA. Specifically, we examine how accompanying spouses described their social integration and changes in roles and identities, how perceptions of sacrifice for their partner related to their adjustment experiences, how they gained entrée and navigated social spaces in the host community and what they believe enhanced and hindered their adjustment and social integration. Accompanying spouses portrayed themselves as initiators who created meaningful experiences by locating and taking advantage of opportunities and resources, including language and culture classes, to forge new identities and structure their lives. The findings can inform the design, development and dissemination of adult education and support services for accompanying spouses, especially in geographically isolated areas.     

Beyond learning by doing: an exploration of critical incidents in outdoor leadership education

This paper argues that outdoor leader education and training is characterized by the development of procedural skills at the expense of crucial but usually ignored non-technical skills (e.g. contextualized decision-making and reflection). This risks producing practitioners with a potentially unsophisticated awareness of the holistic outdoor environment impeding the development of links between theory and practice. This paper analyses the application of critical incident theory to a study of undergraduates in a UK outdoor leadership degree programme in order to examine the processes of developing non-technical reflective skills in the students. The study examines a range of critical incidents in a purposive homogeneous sample of students who were asked to identify and reflect on critical incidents in practice settings of their own choice. These settings spanned from the United Kingdom to remote locations overseas. Qualitative data analysis was carried out using interpretative phenomenological analysis. The findings indicated that outdoor leadership programmes need to develop a broader and holistic skills base rather than concentrate on primarily physical and technical skills. A focus on the critical incident method early in education has the potential to equip practitioners with the holistic and complex set of skills required in the contemporary outdoor workplace.     

Retrieval practice after multiple context changes,but not long retention intervals,reduces the impact of a final context change on instrumental behavior

Recent evidence from this laboratory suggests that a context switch after operant learning consistently results in a decrement in responding. One way to reduce this decrement is to train the response in multiple contexts. One interpretation of this result, rooted in stimulus sampling theory, is that conditioning of a greater number of common stimulus elements arising from more contexts causes better generalization to new contexts. An alternative explanation is that each change of context causes more effortful retrieval, and practice involving effortful retrieval results in learning that is better able to transfer to new situations. The current experiments were designed to differentiate between these two explanations for the first time in an animal learning and memory task. Experiment 1 demonstrated that the detrimental impact of a context change on an instrumental nose-poking response can be reduced by training the response in multiple contexts. Experiment 2 then found that a training procedure which inserted extended retention intervals between successive training sessions did not reduce the detrimental impact of a final context change. This occurred even though the inserted retention intervals had a detrimental impact on responding (and, thus, presumably retrieval) similar to the effect that context switches had in Experiment 1. Together, the results suggest that effortful retrieval practice may not be sufficient to reduce the negative impact of a context change on instrumental behavior. A common elements explanation which supposes that physical and temporal contextual cues do not overlap may account for the findings more readily.     

Talk the talk: Learner-generated podcasts as catalysts for knowledge creation

Podcasting allows audio content from one or more user-selected feeds or channels to be automatically downloaded to one's computer as it becomes available, then later transferred to a portable player for consumption at a convenient time and place. It is enjoying phenomenal growth in mainstream society, alongside other Web 2.0 technologies that enable Internet users to author and distribute rich media content quickly and easily. Instead of using the technology for the mere recording and dissemination of lectures and other instructor-centred information, the project reported on in this article focused on enabling students to create their own podcasts for distribution to their peers. The article describes how engaging in the podcasting exercise promoted collaborative knowledge building among the student-producers, as evidenced through focus-group interviewing and an analysis of the products of their shared dialogue and reflection. The findings suggest that the collaborative development of audio learning objects enabling student conceptualisations of disciplinary content to be shared with peers is a powerful way of stimulating both individual and collective learning, as well as supporting social processes of perspective-taking and negotiation of meaning that underpin knowledge creation.     

Testing an Idealized Dynamic Cascade Model of the Development of Serious Violence in Adolescence

A dynamic cascade model of development of serious adolescent violence was proposed and tested through prospective inquiry with 754 children (50% male; 43% African American) from 27 schools at 4 geographic sites followed annually from kindergarten through Grade 11 (ages 5–18). Self, parent, teacher, peer, observer, and administrative reports provided data. Partial least squares analyses revealed a cascade of prediction and mediation: An early social context of disadvantage predicts harsh–inconsistent parenting, which predicts social and cognitive deficits, which predicts conduct problem behavior, which predicts elementary school social and academic failure, which predicts parental withdrawal from supervision and monitoring, which predicts deviant peer associations, which ultimately predicts adolescent violence. Findings suggest targets for in‐depth inquiry and preventive intervention.     

The WCCES and Intercultural Dialogue: Historical Perspectives and Continuing Challenges

The World Council of Comparative Education Societies (WCCES) has been strongly concerned with intercultural dialogue since the Council was created in 1970. Indeed advancement of education “for international understanding in the interests of peace, intercultural cooperation, mutual respect among peoples and observance of human rights” is one of the goals built into the WCCES Statutes. This paper begins with a focus on the origins and goals of the WCCES, noting in particular links with the mission of UNESCO. The paper then considers dimensions of evolution in the work of the WCCES in the domain of intercultural dialogue. It underlines the growth of the WCCES and the continuing challenges for securing balanced representation of voices and perspectives.