Reduction of water evaporation in polymerase chain reaction microfluidic devices based on oscillating-flow   总被引：1，自引：0，他引：1  

Alessandro Polini  Elisa Mele  Anna Giovanna Sciancalepore  Salvatore Girardo  Adriana Biasco  Andrea Camposeo  Roberto Cingolani  David A. Weitz    Dario Pisignano 《Biomicrofluidics》2010,4(3)

Producing polymeric or hybrid microfluidic devices operating at high temperatures with reduced or no water evaporation is a challenge for many on-chip applications including polymerase chain reaction (PCR). We study sample evaporation in polymeric and hybrid devices, realized by glass microchannels for avoiding water diffusion toward the elastomer used for chip fabrication. The method dramatically reduces water evaporation in PCR devices that are found to exhibit optimal stability and effective operation under oscillating-flow. This approach maintains the flexibility, ease of fabrication, and low cost of disposable chips, and can be extended to other high-temperature microfluidic biochemical reactors.  相似文献   

Antecedents and Consequences of Coaching Behavior     

Andrea D. Ellinger 《Performance Improvement Quarterly》1999,12(4):45-70

Proponents of the learning organization acknowledge that leaders and managers must assume roles as coaches in organizations that aspire to become learning organizations. The concept of the manager as a coach is becoming increasingly popular as a way to facilitate learning and improve employee performance. Yet, despite the research that has been done on coaching, studies generally focus on characteristics of good coaches, requisite coaching skills, and employees' perceptions of the improvement in managers coaching skills following such training programs. This article describes some of the findings from a larger qualitative critical incident study. Specifically, the triggers for coaching and the outcomes of coaching interventions for the individual employee, manager, and organization are examined and reported here. This study identifies gaps and discrepancies, political, and developmental issues as the primary triggers for coaching. Additionally, this study suggests that managers' commitment to coaching has the potential to impact performance at the individual employee, manager, and organizational level.  相似文献   

Will Undergraduate Students Play Games to Learn How to Conduct Library Research?     

Karen Markey  Professor  Fritz Swanson  Lecturer  Andrea Jenkins  Programmer  Brian Jennings  Programmer  Beth St. Jean  Graduate Student Research Assistant  Victor Rosenberg  Associate Professor  Xingxing Yao  Graduate Student Research Assistant  Robert Frost  Associate Professor 《The Journal of Academic Librarianship》2009,35(4):303-313

This exploratory study examines whether undergraduate students will play games to learn how to conduct library research. Results indicate that students will play games that are an integral component of the course curriculum and enable them to accomplish overall course goals at the same time they learn about library research.  相似文献   

Feedback mechanisms in learning virtual community settings     

Luigi Colazzo Alessio Comai Filippo Davi Andrea Molinari Nicola Villa 《美中教育评论》2010,(1):76-84

This paper introduces a set of services for the creation of on-line surveys, questionnaires, exams and self-assessment tests within a virtual community system used in e-learning settings. The system, called ＂Online Communities＂, is a dynamic web application used as platform for blended learning activities by the Faculty of Economics of the University of Trento. The functionalities added to the platform are contextualized into virtual communities, where activities take place. This allows us to create, submit and analyze questionnaires within and/or outside the boundaries of a community. Furthermore, the system allows to manage libraries of queries organized by the teacher/administrator of the community according to topics and levels of difficulty, in order to produce tests and generate self-assessment sessions on behalf of students. The addition of a questionnaire/ poll/self-assessment tool to a virtual community system can add a lot of interesting features, mainly using the inheritance mechanism implemented among different hierarchically-connected communities. This paper will present these functionalities and highlight one of these services, precisely the one dedicated to self-assessment. In the system, self-assessment tests have indeed a double nature： （1） They are useful to students for checking their own level of preparation; and （2） They are useful to lecturers as an indicator of the level of preparation reached by the students. In order to encourage the use of the system within the whole educational process, and not to limit the real use of the service to the period of the final exams only, the possibility has been foreseen for each participant to share his/her own test results, comparing them with the other members of the community, and even offering real ＂challenges＂, thus transforming passive and ＂solitary＂ learning into something much more stimulating and ＂social＂.  相似文献   

EXPLORING FEAR: ROUSSEAU,DEWEY, AND FREIRE ON FEAR AND LEARNING     

Andrea English  Barbara Stengel 《Educational theory》2010,60(5):521-542

Fear is not the first feature of educational experience associated with the best‐known progressive educational theorists—Jean‐Jacques Rousseau, John Dewey, and Paolo Freire. But each of these important thinkers did, in fact, have something substantive to say about how fear functions in the processes of learning and growth. Andrea English and Barbara Stengel juxtapose the ideas of these thinkers in this essay for three purposes: (1) to demonstrate that there is a progressive tradition that accounts for negative emotion in learning; (2) to explore doubt, discomfort, and difficulty as pedagogically useful, with links to fear as both a prompt for and an impediment to growth; and (3) to suggest that teachers take negative affect into account in their pedagogical practice. In doing so, English and Stengel join with contemporary theorists in and out of education to recognize that affect cannot be left out of social theory and that understanding the play of emotion is an integral part of creating truly educational contexts and experiences. The authors' focus here is on fear in processes of learning.  相似文献   

Leading Developmental Peer Observation of Teaching in Higher Education: Perspectives from Australia and England     

Dallas Wingrove  Linda Hammersley-Fletcher  Angela Clarke  Andrea Chester 《British Journal of Educational Studies》2018,66(3):365-381

Whilst peer observation of teaching is well established as a practice that can enhance teaching quality, the challenge to fully embed this practice in universities remains unresolved. This article analyses the perspectives of 18 university leaders (nine Australian and nine English) drawn from a range of school-based leaders to senior leaders of learning and teaching. Our study indicates that some of the challenges associated with leading such schemes can be mitigated through approaches to educational leadership that enact a respectful and collegiate ethos. This we suggest can support developmental academic engagement in peer observation for positive and lasting change.  相似文献   

Divide to connect: Reorganization through R&D unit spinout as linking context of intra-corporate networks     

Bruno Cirillo  Stefano Breschi  Andrea Prencipe 《Research Policy》2018,47(9):1585-1600

The paper examines the formation of clique-spanning ties in intra-corporate co-invention networks, by focusing on the impact of R&D unit spinouts. Using data on thirty-one spinouts in eight large U.S. information and communication technology corporations, we show that the reorganization of R&D units through corporate spinouts is associated with an increase in the extent to which inventors employed in the unit collaborate with inventors located in other cliques within the corporate co-invention network. Interestingly, the spinout effect spills over to all members of the clique of spun-out inventors, also including those who remain with the parent firm. The interpretation of these empirical findings, grounded on existing theories and on the views of inventors and executives involved in the reorganization events, suggests that corporate spinouts generate a shock in intra-corporate research collaboration dynamics, which loosens clique lock-in effects and contributes to reset cliques’ boundaries in the intra-corporate research network.  相似文献   

Bioimpedance patterns and bioelectrical impedance vector analysis (BIVA) of road cyclists     

Andrea Giorgi  Maurizio Vicini  Luca Pollastri  Erica Lombardi  Emilio Magni  Andrea Andreazzoli 《Journal of sports sciences》2018,36(22):2608-2613

Bioelectrical impedance vector-analysis (BIVA) describes cell-mass, cell function and hydration status of an individual or a group. The goal of the present investigation was to provide bioelectrical impedance data for 525 male road cyclists (155 professionals, 79 elite, 59 elite-youth, and 232 amateurs) at the time of their optimal performance level. Data were plotted on the resistance-reactance (R-Xc) graph to characterize cyclists group vectors using BIVA. Compared to the general male population, the mean vector position of the road cyclists indicates a higher body cell mass (BCM) and phase angle (p<0.001). The vector position of the high-performance, compared to the amateur cyclists showed similar patterns with higher BCM and phase angles and higher reactance values for the high-performance athletes (p<0.001). The bio-impedance data were used to calculate the 50%, 75%, and 95% tolerance ellipses of each group of cyclists. The characteristic vector positions of the road cyclists indicate normal hydration and greater muscle mass and function of the high-performance cyclists compared to amateur cyclists and the normal population. The cyclists specific tolerance ellipses, particularly the high-performance cyclists might be used for classifying a cyclist according to the individual vector position and to define target vector regions for lower level cyclists.  相似文献   

Relationship between performance-based and laboratory tests for lower-limb muscle strength and power assessment in healthy older women     

Roberta Forte  Andrea Macaluso 《Journal of sports sciences》2013,31(13):1431-1436

Abstract

The aim of the study was to assess the relationship between performance-based and laboratory tests for muscular strength and power assessment in older women. Thirty-two women aged 68.8 ± 2.8 years were recruited. All participants were asessed for: (a) two performance-based tests – the box-stepping test (mean 296 ± 51 J) and two-revolution maximum test (mean 7.1 ± 2 kg) performed while pedalling on a cycle ergometer; and (b) muscular function tests – maximal instantaneous peak power jumping on a force platform (mean 1528 ± 279 W); maximal voluntary contraction (MVC) during knee extension (mean 601 ± 571 N) and leg press (mean 626 ± 126 N), and leg press power (mean 483 ± 98 W) on a dynamometer. Using univariate analysis, performance-based tests were compared with laboratory muscle strength and power measurements. Muscle power correlated most strongly with the performance-based tests for both jumping and leg press power (r-values between 0.67 and 0.75; P < 0.01). The correlation with muscle strength measures ranged between 0.48 and 0.61 (P < 0.01). The proposed tests may have particular relevance in geriatric and rehabilitation environments as they represent an easy, practical, and inexpensive alternative for the assessment of muscular strength and power.  相似文献   

Physical fitness of primary school children in relation to overweight prevalence and physical activity habits     

Rossella Sacchetti  Andrea Ceciliani  Andrea Garulli  Andrea Masotti  Giuseppe Poletti  Patrizia Beltrami 《Journal of sports sciences》2013,31(7):633-640

Abstract

A cross-sectional study was carried out to analyse, through a limited number of fitness tests, the main conditioning and coordinative abilities in children aged 8–9 years, and their relationship with gender, anthropometric variables and physical activity habits. The height and weight of 256 boys and 241 girls were measured and information about physical activity habits was collected using a self-administered questionnaire. Physical performance was assessed by means of a few standardised tests: ‘sit & reach’, medicine-ball forward throw, standing long jump, 20 m running speed, and forward roll test. In both boys and girls, body weight and Body Mass Index (BMI) were positively correlated with the medicine-ball throw performances and negatively correlated for the standing long jump and speed tests, while no association was found with tests measuring back flexibility and total body coordination. Daily physical activity and participation in sport were not significantly correlated with body weight and BMI, but were positively associated with children's motor performance. The standardised fitness tests selected in the current study have been found to be suitable to identify fitness levels of primary school children. Thanks to their limited number and ease of measurement, they can be used in any school context to classify children and for monitoring the effects of targeted interventions promoting physical activity.  相似文献