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1.
Edward A. Friedman 《The Information Society》2013,29(3-4):269-320
Abstract This paper reviews developments in the work force as they bear on training needs from entry level skills through professional continuing education. It summarizes the state of the art in various categories of information technology as they apply to education and training, including interactive videodisc, satellite communications systems, videotex, and artificial intelligence methods. These technologies and their potential are illustrated through case study examples. Policy recommendations are presented for governmental, industrial, and higher educational institution initiatives. 相似文献
2.
Over the past decade, education reform and teacher training projects have spent a great deal of effort to create and support sustainable, scalable online communities of education professionals. For the most part, those communities have been created in isolation from the existing local professional communities within which the teachers practice. We argue that focusing on online technology solely as a mechanism to deliver training and/or create online networks places the cart before the horse by ignoring the Internet's even greater potential to help support and strengthen local communities of practice within which teachers work. In this article we seek guideposts to help education technologists understand the nature of local K-12 education communities of practice--specifically their reciprocal relationship with teacher professional development and instructional improvement interventions--as a prerequisite to designing online sociotechnical infrastructure that supports the professional growth of education professionals. 相似文献
3.
《普罗米修斯》2012,30(3):269-281
Abstract This paper provides a detailed analysis of the change process of academic science. The change pressures currently visible in UK science have been conceptualised as the product of three interdependent dynamics: a shift towards neo‐liberal ideologies and discourses of government; a process of reconstitution of the relationship between government and science; and the resulting reshaping of science itself. Focusing on the universities and academic science, we argue that this process of transformation has adverse consequences the end result of which may be a loss of capacity within the science system to maintain knowledge bases. 相似文献
4.
Bipolar membranes (BMs) have interesting applications within the field of bioelectronics, as they may be used to create non-linear ionic components (e.g., ion diodes and transistors), thereby extending the functionality of, otherwise linear, electrophoretic drug delivery devices. However, BM based diodes suffer from a number of limitations, such as narrow voltage operation range and/or high hysteresis. In this work, we circumvent these problems by using a novel polyphosphonium-based BM, which is shown to exhibit improved diode characteristics. We believe that this new type of BM diode will be useful for creating complex addressable ionic circuits for delivery of charged biomolecules.Combined electronic and ionic conduction makes organic electronic materials well suited for bioelectronics applications as a technological mean of translating electronic addressing signals into delivery of chemicals and ions.1 For complex regulation of functions in cells and tissues, a chemical circuit technology is necessary in order to generate complex and dynamic signal gradients with high spatiotemporal resolution. One approach to achieve a chemical circuit technology is to use bipolar membranes (BMs), which can be used to create the ionic equivalents of diodes2, 3, 4, 5 and transistors.6, 7, 8 A BM consists of a stack of a cation- and an anion-selective membrane, and functions similar to the semiconductor PN-junction, i.e., it offers ionic current rectification9, 10 (Figure (Figure1a).1a). The high fixed charge concentration in a BM configuration make them more suited in bioelectronic applications as compared to other non-linear ionic devices, such as diodes constructed from surface charged nanopores11 or nanochannels,12 as the latter devices typically suffers from reduced performance at elevated electrolyte concentration (i.e., at physiological conditions) due to reduced Debye screening length.13 However, a unique property of most BMs, as compared to the electronic PN-junction and other ionic diodes, is the electric field enhanced (EFE) water dissociation effect.10, 14 This occurs above a threshold reverse bias voltage, typically around −1 V, as the high electric field across the ion-depleted BM interface accelerates the forward reaction rate of the dissociation of water into H+ and OH− ions. As these ions migrate out from the BM, there will be an increase in the reverse bias current. The EFE water dissociation is a very interesting effect and is commonly used in industrial electrodialysis applications,15 where highly efficient water dissociating BMs are being researched.16 Also, BMs have also been utilized to generate H+ and OH− ions in lab-on-a-chip applications.2, 17 However, the EFE water dissociation effect diminishes the diode property of BMs when operated outside the ±1 V window, which is unwanted in, for instance, chemical circuits and addressing matrices for delivery of complex gradients of chemical species. The effect can be suppressed by incorporating a neutral electrolyte inside the BM,10, 18 for instance, poly(ethylene glycol) (PEG).2, 6, 7 However, as previously reported,2 the PEG volume will introduce hysteresis when switching from forward to reverse bias, due to its ability to store large amounts of charges. This was circumvented by ensuring that only H+ and OH− are present in the diode, which recombines into water within the PEG volume. Such diodes are well suited as integrated components in chemical circuits for pH-regulation, due to the in situ formed H+ and OH−, but are less attractive if, for instance, other ions, e.g., biomolecules, are to be processed or delivered in and from the circuit. Furthermore, a PEG electrolyte introduces additional patterning layers, making device downscaling more challenging. This is undesired when designing complex, miniaturized, and large-scale ionic circuits. Thus, there is an interest in BM diodes that intrinsically do not exhibit any EFE water dissociation, are easy to miniaturize, and that turn off at relatively high speeds. It has been suggested that tertiary amines in the BM interface are important for efficient EFE water dissociation,19, 20, 21 as they function as a weak base and can therefore catalyze dissociation of water by accepting a proton. For example, anion-selective membranes that have undergone complete methylation, converting all tertiary amines to quaternary amines, shows no EFE water dissociation,19 although this effect was not permanent, as the quaternization was reversed upon application of a current. Similar results were found for anion-selective membranes containing alkali-metal complexing crown ethers as fixed charges.21 Also, EFE water dissociation was not observed or reduced in BMs with poor ion selectivity, for example, in BMs with low fixed-charge concentration5 or with predominantly secondary and tertiary amines in the anion-selective membrane,22 as the increased co-ion transport reduces the electric field at the BM interface. However, due to decreased ion selectivity, these membranes show reduced rectification. In this work, we present a non-amine based BM diode that avoids EFE water dissociation, enables easy miniaturization, and provides fast turn-off speeds and high rectification.Open in a separate windowFigure 1(a) Ionic current rectification in a BM. In forward bias, mobile ions migrate towards the interface of the BM. The changing ion selectivity causes ion accumulation, resulting in high ion concentration and high conductivity. At high ion concentration, the selectivity of the membranes fails (Donnan exclusion failure), and ions start to pass the BM. In reverse bias, the mobile ions migrate away from the BM, eventually giving a zone with low ion concentration and low conductivity. Reverse bias can cause EFE water dissociation, producing H+ and OH- ions. (b) Chemical structures of PSS, qPVBC, and PVBPPh3. (c) The device used to characterize the BMs and the BM1A, BM2A, and BM1P designs. The BM interfaces are 50 × 50 μm.An anion-selective phosphonium-based polycation (poly(vinylbenzyl chloride) (PVBC) quaternized by triphenylphospine, PVBPPh3) was synthesized and compared to the ammonium-based polycation (PVBC quaternized by dimethylbenzylamine, qPVBC) previously used in BM diodes2 and transistors,7, 8 when included in BM diode structures together with polystyrenesulfonate (PSS) as the cation-selective material (Figure (Figure1b).1b). Three types of BM diodes were fabricated using standard photolithography patterning (Figure (Figure1c),1c), either with qPVBC (BM1A and BM2A) or PVBPPh3 (BM1P) as polycation and either with (BM2A) or without PEG (BM1A and BM1P). Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) electrodes covered with aqueous electrolytes were used to convert electronic input signals into ionic currents through the BMs, according to the redox reaction PEDOT+:PSS− + M+ + e− ↔ PEDOT0 + M+:PSS−.The rectifying behavior of the diodes was evaluated using linear sweep voltammetry (Figure (Figure2).2). The BM1A diode exhibited an increase in the reverse bias current for voltages lower than −1 V, a typical signature of EFE water dissociation,10, 14 which decreased the current rectification at ±4 V to 6.14. No such deviation in the reverse bias current was observed for BM2A and BM1P, which showed rectification ratios of 751 and 196, respectively. In fact, for BM1P, no evident EFE water dissociation was observed even at −40 V (see inset of Figure Figure2).2). Thus, the PVBPPh3 polycation allows BM diodes to operate at voltages beyond the ±1 V window with maintained high ion current rectification.Open in a separate windowFigure 2Linear sweep voltammetry from −4 to +4 V (25 mV/s) for the BM diodes. The inset shows BM1P scanning from −40 V to +4 V (250 mV/s).The dynamic performance of the diodes was tested by applying a square wave pulse from reverse bias to a forward bias voltage of 4 V with 5–90 s pulse duration (Figure (Figure3).3). To access the amount of charge injected and extracted during the forward bias and subsequent turn off, the current through the device was integrated. For BM2A, we observed that the fall time increased with the duration of the forward bias pulse. This hysteresis is due to the efficient storage of ions in the large PEG volume, with no ions crossing the BM due to Donnan exclusion failure.2 As a result, during the initial period of the return to reverse bias, a large amount of charge needs to be extracted in order to deplete the BM. After a 90 s pulse, 90.6% of the injected charge during the forward bias was extracted before turn-off. This may be contrasted with BM1P, where the fall time is hardly affected by the pulse duration, and the extracted/injected ratio is only 15.4% for a 90 s pulse. For this type of BM, the interface quickly becomes saturated with ions during forward bias, leading to Donnan exclusion failure and transport of ions across the BM.4 Thus, less charge needs to be extracted to deplete the BM, allowing for faster fall times and significantly reduced hysteresis.Open in a separate windowFigure 3Switching characteristics (5, 10, 20, 30, 60, or 90 s pulse) and ion accumulation (at 90 s pulse) of the BM2A and BM1P diodes. BM1A showed similar characteristics as BM1P when switched at ±1V (see supplementary material).24Since the neutral electrolyte is no longer required to obtain high ion current rectification over a wide potential range, the size of the BM can be miniaturized. This translates into higher component density when integrating the BM diode into ionic/chemical circuits. A miniaturized BM1P diode was constructed, where the interface of the BM was shrunk from 50 μm to 10 μm. The 10 μm device showed similar IV and switching characteristics as before (Figure (Figure4),4), but with higher ion current rectification ratio (over 800) and decreased rise/fall times (corresponding to 90%/–10% of forward bias steady state) from 10 s/12.5 s to 4 s/4 s. Since the overlap area is smaller, a probable reason for the faster switching times is the reduced amount of ions needed to saturate and deplete the BM interface. In comparison to our previous reported low hysteresis BM diode,2 this miniaturized polyphosphonium-based devices shows the same rise and fall times but increased rectification ratio.Open in a separate windowFigure 4(a) Linear sweep voltammetry and (b) switching performance of a BM1P diode with narrow junction.In summary, by using polyphosphonium instead of polyammonium as the polycation in BM ion diodes the EFE water dissociation can be entirely suppressed over a large operational voltage window, supporting the theory that a weak base, such as a tertiary amine, is needed for efficient EFE water dissociation.17, 18 As no additional neutral layer at the BM interface is needed, ion diodes that operate outside the usual EFE water dissociation window of ±1 V can be constructed using less active layers, fewer processing steps and with relaxed alignment requirement as compared to polyammonium-based devices. This enables the fabrication of ion rectification devices with an active interface as low as 10 μm. Furthermore, the exclusion of a neutral layer improves the overall dynamic performance of the BM ion diode significantly, as there is less hysteresis due to ion accumulation. Previously, the hysteresis of BM ion diodes has been mitigated by designing the diode so that only H+ and OH− enters the BM, which then recombines into water.2 Such diodes also show high ion current rectification ratio and switching speed but are more complex to manufacture, and their application in organic bioelectronic systems is limited due to the H+/OH− production. By instead using the polyphosphonium-based BM diode, reported here, we foresee ionic, complex, and miniaturized circuits that can include charged biomolecules as the signal carrier to regulate functions and the physiology in cell systems, such as in biomolecule and drug delivery applications, and also in lab-on-a-chip applications. 相似文献
5.
《普罗米修斯》2012,30(2):165-177
Abstract This paper is concerned with the scope for developing countries to benefit from the Internet in non‐synchronous ways that is, in cases where some delay is involved in the delivery of information, as compared with the real‐time alternative used in developed countries. The first part of the paper draws on insights from Becker and others, to argue that poor people in poor countries are wont to exchange (relatively abundant) time for reductions in the cost of Internet use. The second part of the paper then examines whether such time‐intensive products actually exist and to the extent they do, how the required degree of cost reductions are effected in practice. I conclude that time‐intensive Internet technology represents a highly promising opportunity for developing countries to close the digital divide, an opportunity that warrants serious academic scrutiny. 相似文献
6.
The relationship of technology policy to economic and industrial development has become a subject of debate between those who argue that market forces should determine how technology is produced and used and those who believe that government has a role in supporting investment in technology use and the development of high‐technology industries. This article looks at the effects of national technology policy in promoting the production of computer hardware and software in Asia‐Pacific countries during the 1980s. It also analyzes the relationship between various environmental factors and computer production and looks at the interaction between environment and policy. It finds three types of environmental factors associated with level of computer production: human resources, in the form of scientists and engineers; the presence of complementary industries, particularly electronics production; and expenditures on research and development. It also finds that hardware production is higher in countries with national computer plans but that software production does not appear to be associated with efforts by the government to promote the computer industry. 相似文献
7.
《普罗米修斯》2012,30(3):325-347
Abstract This article examines a series of controversies within the life sciences over data sharing. Part 1 focuses upon the agricultural biotechnology firm Syngenta publishing data on the rice genome in the journal Science, and considers proposals to reform scientific publishing and funding to encourage data sharing. Part 2 examines the relationship between intellectual property rights and scientific publishing, in particular copyright protection of databases, and evaluates the declaration of the Human Genome Organisation that genomic databases should be global public goods. Part 3 looks at varying opinions on the information function of patent law, and then considers the proposals of Patrinos and Drell to provide incentives for private corporations to release data into the public domain. 相似文献
8.
《普罗米修斯》2012,30(3):341-348
Philip Pullman writes books for children. His best known is probably the His Dark Materials trilogy, Northern Lights, The Subtle Knife and The Amber Spyglass. His most contentious probably The Good Man Jesus and the Scoundrel Christ. He writes not so much to explain as to allow the reader’s own imagination to work on his words. The same purpose is at the core of his belief in the value of public libraries. The debate on the role and future of public libraries in the UK was marked by the accusation that authors had their own interests in mind when they objected to library closures. Philip Pullman leapt to the attack. This is an edited version of his mauling of Oxfordshire County Council. 相似文献
9.
Psychiatry interacts with contemporary Western views: the DSM‐III innovation and its adverse effects
《普罗米修斯》2012,30(3):245-266
Economic studies of innovation are relevant to the mental health sector, not just for innovations in more conventional industries, such as telecommunications. We present an economic examination of the impact of an innovation in the mental health sector. The innovation examined here was first adopted in 1980 with the publication of a new edition of the nosology (or classification) for the diagnosis of mental illnesses and disorders, which is known familiarly as the DSM‐III. In our analysis, we incorporate the impact of that innovation, and another major force relevant to psychiatric diagnosis during that time period, i.e. a trend in the West towards the medicalisation of normal sorrows. This is now a documented phenomenon. By using conventional price–quantity space and focussing attention on the quantity outcome, we are able to consider the impact of these concurrent forces on the false positive rate in the diagnosis of mental illnesses in the West and on efficacious diagnostic practice in this sector. Diagnostic efficacy is relevant to treatment, but it is relevant also to resource allocation in the mental health sector. Our analysis highlights the vital place of innovation in diagnostic practices, and the funding of this, in the mental health sector. 相似文献
10.
《普罗米修斯》2012,30(2):167-180
We assess the benefits from transatlantic collaboration in technology policy for publicly‐funded R&D space projects such as Galileo, a proposed European radio‐navigation space project. An industrial organisation methodology is employed to model negative security spillovers of ‘unilateral’ space projects such as Galileo, or space‐based anti‐ballistic missile defence, on the public sector of the other region (the US vs. the European Union). The findings imply that transatlantic co‐ordination in technology policy is required to allow the respective space industries (in the US and the European Union) to exploit the benefits of cross‐border strategic research partnerships (SRPs). This coordination not only reduces the costs of the respective programmes, but also addresses security concerns. 相似文献
11.
James Christopher Westland 《The Information Society》2013,29(3):127-138
Abstract Recent interest has been expressed in the potential of information technology to create new kinds of monopolies. This paper looks at production and marketing factors in the information services industry which may increase concentration in the hands of fewer producers, potentially leading to monopoly formation. The research develops an economic model of topic‐specific market concentration and delineates the factors which might cause monopolies to occur in the markets of information data base production firms. The model shows that market concentration rises with inelastic demand, reduced marginal costs and efficient technology, and increased data acquisition costs exacerbated by low rates of data obsolescence. These effects are empirically investigated in the DIALOG group of data bases. The results of the research have implications for corporate information systems and information systems in the public sector. 相似文献
12.
Yun Feng Yaonan Wang Jun-Wei Wang Han-Xiong Li 《Journal of The Franklin Institute》2021,358(2):1656-1672
Detection and estimation of abnormalities for distributed parameter system (DPS) have wide applications in industry, e.g., battery thermal fault diagnosis, quality monitoring of hot-rolled strip laminar cooling process. In this paper, the abnormal spatio-temporal (S-T) source detection and estimation problem for a linear unstable DPS is first studied. The proposed methodology consists of two steps: first, an abnormality detection filter (ADF) which generates a residual signal for abnormality detection in the time domain is constructed using pointwise measurement; Then, an adaptive Luenberger-type PDE observer including an adaptive estimation algorithm is designed and triggered only when an alarm raises from the ADF. Theoretic analysis based on the spatial domain decomposition approach is presented to show the convergence of the estimation errors. Finally, an illustrative example is presented to show the performance of the proposed method. 相似文献
13.
Toni Carbo Bearman 《The Information Society》2013,29(2):71-75
Abstract Computer science in the United States is hard pressed to show broad utility to help justify billion dollar research programs and the value of educating well over 40,000 bachelor of science and master of science specialists annually in the United States. The Computer Science and Telecommunications Board of the U.S. National Research Council recently has issued a report, “Computing the Future” (Hartmanis &; Lin 1992), which sets a new agenda for computer science. The report recommended that computer scientists broaden their conceptions of the discipline to include computing applications and domains to help understand them. This article argues that many computer science graduates need some skills in analyzing human organizations to help develop appropriate systems requirements, because they are trying to develop high‐performance computing applications that effectively support higher performance human organizations. It is time for academic computer science to embrace organizational analysis (the field of Organizational Informatics) as a key area of research and instruction. 相似文献
14.
《普罗米修斯》2012,30(3):323-339
This paper studies the evolution of the photovoltaics industry in Australia, Germany and Japan taking a comparative perspective. A modification of the sectoral innovation system framework is used to discuss: knowledge and technologies, actors and interactions, institutions and funding, development of markets and technological structure, as a way to understand the changes. In the process of transition from niche to mass production, national players have specialised in different activities, and the institutions’ building block has been a key determinant. In the case of Australia, it is also the least developed area which ultimately exposes the country to losing its innovation benefits. 相似文献