Schooling for technological change — Two nations once again     

Brendan P. Ryan 《Interchange》1989,20(3):17-34

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Teachers’ Perceptions of Professional Incompetence and Barriers to the Dismissal Process     

Brendan P. Menuey 《Journal of Personnel Evaluation in Education》2005,18(4):309-325

The problem of teacher incompetence is a serious one, affecting large numbers of American public school students. There is a significant discrepancy between estimated rates of incompetent teachers and the number of teachers actually dismissed on grounds of incompetence. This study sought to uncover the perceptions of teachers regarding a definition of professional incompetence, strategies used with incompetent teachers, and barriers to the dismissal process, through the use of a survey with more than 200 elementary school teachers in Virginia and follow-up interviews with seven of these participants. The researcher found that teachers rated classroom behaviors to be the most important factors towards a definition of professional incompetence. The teachers involved also rated the commonness of strategies used with incompetent teachers, placing dismissal among the least common actions taken by administrators, and revealed that they believed union protection, legal and other expenses, and difficulty providing documentation prevented administrators from dismissing incompetent teachers.  相似文献   

Bridge21: teamwork,technology and learning. A pragmatic model for effective twenty-first-century team-based learning     

John Lawlor  Claire Conneely  Elizabeth Oldham  Kevin Marshall  Brendan Tangney 《Technology, Pedagogy and Education》2018,27(2):211-232

There have been calls for decades by many educational writers and commentators for a new model of learning to facilitate what is generally described as twenty-first-century learning. Central to this challenge is the required shift in responsibility for who leads and owns the learning – from teacher to student. Such a shift requires a pragmatic pedagogical model to facilitate the transfer of control and ownership of learning. Vygotsky’s ‘more able other’ identified the peer as a key figure in learning. Teamwork facilitates project-based learning and, when mediated with technology, proves an effective partner in creating an engaging and autonomous learning experience. This paper describes the rationale for the design of a team-based model of twenty-first-century learning, particularly drawing upon the team-based learning model of the World Scout Movement. Results from a year-long study of the implementation of the model in an out-of-school context with 288 second-level students are presented. The authors argue that Bridge21 is a candidate learning model for effective, implementable, twenty-first-century, team-based learning.  相似文献   

Faculty Perceptions of Students in Life and Physical Science Research Labs     

Claire P. Gonyo  Brendan Cantwell 《Innovative Higher Education》2015,40(4):317-329

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“教授说书”模式对MOOCs的启示---以《百家讲坛》为例     

吴沧海  王琳  熊焕亮  王映龙 《科教文汇》2015,(12)

在学习型社会建设的背景下,教育技术为终身教育的实现提供了一种新的学习方式,并且教育技术网络化和媒体化又为实现终身教育、构建学习化社会搭建了一个重要的平台。作为时下炙手可热的学术性电视节目———《百家讲坛》的成功经验可为MOOCs课程的建设提供新的思路,更好地服务于教育,加快学习型社会的发展进程。  相似文献   

Enhancing conjugation rate of antibodies to carboxylates: Numerical modeling of conjugation kinetics in microfluidic channels and characterization of chemical over-exposure in conventional protocols by quartz crystal microbalance     

Sasan Asiaei  Brendan Smith  Patricia Nieva 《Biomicrofluidics》2015,9(6)

This research reports an improved conjugation process for immobilization of antibodies on carboxyl ended self-assembled monolayers (SAMs). The kinetics of antibody/SAM binding in microfluidic heterogeneous immunoassays has been studied through numerical simulation and experiments. Through numerical simulations, the mass transport of reacting species, namely, antibodies and crosslinking reagent, is related to the available surface concentration of carboxyl ended SAMs in a microchannel. In the bulk flow, the mass transport equation (diffusion and convection) is coupled to the surface reaction between the antibodies and SAM. The model developed is employed to study the effect of the flow rate, conjugating reagents concentration, and height of the microchannel. Dimensionless groups, such as the Damköhler number, are used to compare the reaction and fluidic phenomena present and justify the kinetic trends observed. Based on the model predictions, the conventional conjugation protocol is modified to increase the yield of conjugation reaction. A quartz crystal microbalance device is implemented to examine the resulting surface density of antibodies. As a result, an increase in surface density from 321 ng/cm², in the conventional protocol, to 617 ng/cm² in the modified protocol is observed, which is quite promising for (bio-) sensing applications.Microfluidics have been implemented in various bio-medical diagnostic applications, such as immunosensors and molecular diagnostic devices.¹ In the last decade, a vast number of biochemical species has been detected by microfluidic-based immunosensors. Immunosensors are sensitive transducers which translate the antibody-antigen reaction to physical signals. The detection in an immunosensor is performed through immobilization of an antibody that is specific to the analyte of interest.² The antibody is often bound to the transducing surface of the sensor covered by self-assembled monolayers (SAMs). SAMs are organic materials that form a thin, packed and robust interface on the surface of noble metals like that of gold, suitable for biosensing applications.³ Thiolic SAMs have a “head” group that shows a high affinity to being chemisorbed onto a substrate, typically gold. The SAMs'' carboxylic functional group of the “tail” end can be linked to an amine terminal of an antibody to form a SAM/antibody conjugation.^3,4 The conjugation process is usually accomplished in the presence of carbodiimides, such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). A yield increasing additive, N-Hydroxysuccinimide (NHS), is often used to enhance the surface loading density of the antibody.^4,5A typical reaction for coupling the carboxylic acid groups of SAMs with the amine residue of antibodies in the presence of EDC/NHS is depicted in Figure ​Figure11.⁴ NHS promotes the generation of an active NHS ester (k₂ reaction path). The NHS ester is capable of efficient acylation of amines, including antibodies (k₃ reaction path). As a result, the amide bond formation reaction, which typically does not progress efficiently, can be enhanced using NHS as a catalyst.⁴Open in a separate windowFIG. 1.NHS catalyzed conjugation of antibodies to carboxylic-acid ended SAMs through EDC mediation (Adapted from G. T. Hermanson, Bioconjugate Techniques, 2nd. Edition. Copyright 2008 by Elsevier⁴). EDC reacts with the carboxylic acid and forms o-acylisourea, a highly reactive chemical that reacts with NHS and forms an NHS ester, which quickly reacts with an amine (i.e., antibody) to form an amide.A number of groups have studied EDC/NHS mediated conjugation reactions such as the ones depicted in Figure ​Figure1.1. The general stoichiometry of the reaction involves a carboxylic acid (SAM), an amine (antibody), and EDC to produce the final amide (antibody conjugated SAM) and urea. However, the recommended concentration ratio of the crosslinking reagents inside the buffer, i.e., the ratio of EDC and NHS with respect to adsorbates and each other, varies from one study to another.⁶ The kinetics of the reactions outlined in Figure ​Figure11 have also been investigated,^4,6–8 but only in the absence of NHS for EDC or carboxylic acids in aqueous solutions.⁸ A relatively recent experimental study verified the catalytic role of the yield-increasing reagent N-hydroxybenzotriazole (HOBt), which acts similarly to NHS.⁷ In this study, the amide formation rate (k₃ reaction path, Figure ​Figure1)1) was found to be dependent on the concentration of the carboxylic acid and EDC in the buffer solution, and independent of the amine and catalyst reagent concentration. The same group also showed that the amide bond formation kinetics is controlled by the reaction between the carboxylic acid and the EDC to give the O-acylisourea, which they marked as the rate-determining step (k₁ reaction path, Figure ​Figure11).The k₁ reaction path, or the conjugation reaction, is usually a lengthy process and takes between 1 and 3 h.^4,9 Compared to k₁, the k₂ and ?k₃ reactions are considerably faster. Microfluidics has the potential to enhance the kinetics of these reactions using the flow-through mode.^10,11 This improvement occurs because while conventional methods rely only on diffusion as the primary reagent transport mode, microfluidics adds convection to better replenish the reagents to the reaction surfaces. However, there are many fundamental fluidic and geometrical parameters that might affect the process time and reagents consumption in a microfluidics environment, such as concentration of antibodies and reagents, flow rate, channel height, and final surface density of antibodies. A model that studies the kinetics of conjugation reaction against all these parameters would therefore be helpful for the optimization of this enhanced kinetics.There are a number of reports on numerical examination of the kinetics of binding reactions in microfluidic immunoassays.^12–15 All these models developed so far couple the transport of reagents, by diffusion and convection, to the binding on the reaction surface. Myszka''s model assumes a spatially homogeneous constant concentration of reagents throughout the reaction chamber, thus fails to describe highly transport-limited conditions due to the presence of spatial heterogeneity and depletion of the bulk fluid from reagents.^16,17 In transport-limited conditions, the strength of reaction is superior to the rate of transport of reagents to the reaction surface.^18,19 More recently, the convection effects were included in a number of studies, describing the whole kinetic spectrum from reaction-limited conditions to transport-limited reactions.^20–22 Immunoreaction kinetics has also been examined with a variety of fluid driving forces, from capillary-driven flows,²⁰ to electrokinetic flows in micro-reaction patches,²¹ pressure-driven flows in a variety of geometric designs.²² Despite these comprehensive numerical investigations, the fundamental interrelations between the constitutive kinetic parameters, such as concentration, flow velocity, microchannel height, and antibody loading density, have not been studied in detail. In addition, the conjugation kinetics has not yet been exclusively examined.In this paper, a previous model for immunoreaction is modified to study the antibody/SAM conjugation reaction in a microfluidic system. Model findings are used to examine the process times recommended in the literature and possible modification scenarios are proposed. The new model connects the convective and diffusive transport of reagents in the bulk fluid to their surface reaction. The conjugation reaction is studied against fluidic and geometrical parameters such as flow rate, concentration, microchannel height and surface density of antibodies. Damköhler number is used to compare the reaction and fluidic phenomena present and justify the kinetic trends observed. Model predictions are discussed and the main finding on possible overexposure of carboxylates to crosslinking reagents, in conventional protocols, is verified by comparing the resultant antibody loading densities obtained using a quartz crystal microbalance (QCM) set up. The results demonstrate an improved receptor (antibody) loading density which is quite promising for a number of (bio-) sensing applications.^23,24 Major application areas include antibody-based sensors for on-site, rapid, and sensitive analysis of pathogens such as Bacillus anthracis,²³ Escherichia coli, and Listeria monocytogenes, and toxins such as fungal pathogens, viruses, mycotoxins, marine toxins, and parasites.²⁴  相似文献   

Standards,Technology Adoption,and Ownership—But Not All in One Place     

Benjamin Compaine  Brendan Cunningham 《Journal of Media Economics》2013,26(4):187-191

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Three Industries,Three Issues,But a Common Thread of Solid Analytics     

Benjamin Compaine  Brendan Cunningham 《Journal of Media Economics》2013,26(2):65-69

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Human Trafficking: Preparing Counselors to Work with Survivors     

Jenae Thompson  Melinda Haley 《International journal for the advancement of counseling》2018,40(3):298-309

The global crisis of human trafficking involves the exploitation of people for personal gain and affects millions. Survivors often present with symptoms that are not identifiable to untrained clinicians. In this article, we discuss the importance for counselor training, as well as counselor self-efficacy and competency in addressing the needs of human trafficking survivors.  相似文献   

Integrating structural tensions into technological innovation systems analysis: Application to the case of transmission interconnections and renewable electricity in Nova Scotia,Canada     

Brendan Haley 《Research Policy》2018,47(6):1147-1160

This paper augments the technological innovation systems (TIS) framework to provide policy guidance on how to manage interactions between a core technology and its larger sectoral context. A TIS development cycle is presented that combines the TIS framework’s ability to clearly illuminate policy gaps with Erik Dahmén’s idea that technological diffusion creates structural tensions that introduce transformation pressure. This pressure can result in stagnation and unrealized development potential or spur sectoral complementarities and the evolution of a TIS into a larger “development block” of interlinked technological systems. Integrating structural tensions into TIS analysis highlights how the evolution of a focal technology induces technological complementarities and creates a need to continuously re-design policies. This underscores the continued benefit of a technology system perspective, even as a technology matures.The revised TIS framework is applied to a case study of the Canadian province of Nova Scotia that explores how variable renewable electricity diffusion introduces structural tensions with existing electricity grids, requiring the use of complementary technologies that add storage and flexibility. Nova Scotia aggressively developed wind energy and built a high-voltage direct-current transmission line to import hydroelectricity that could back-up variable renewable energy sources like wind.  相似文献