Gallium arsenide deep-level optical emitter for fibre optics

Fibre-optic components fabricated on the same substrate as integrated circuits are important for future high-speed communications. One industry response has been the costly push to develop indium phosphide (InP) electronics. However, for fabrication simplicity, reliability and cost, gallium arsenide (GaAs) remains the established technology for integrated optoelectronics. Unfortunately, the GaAs bandgap wavelength (0.85 microm) is far too short for fibre optics at 1.3-1.5 microm. This has led to work on materials that have a large lattice mismatch on GaAs. Here we demonstrate the first light-emitting diode (LED) that emits at 1.5 microm fibre-optic wavelengths in GaAs using optical transitions from arsenic antisite (As(Ga)) deep levels. This is an enabling technology for fibre-optic components that are lattice-matched to GaAs integrated circuits. We present experimental results showing significant internal optical power (24 mW) and speed (in terahertz) from GaAs optical emitters using deep-level transitions. Finally, we present theory showing the ultimate limit to the efficiency-bandwidth product of semiconductor deep-level optical emitters.     

Suggestions for content selection and presentation in high school computer textbooks

Based on the findings from reviewing 32 textbooks in the past four years for Taiwan’s Ministry of Education, we have identified common problems in the reviewed textbooks and analyzed their inadequacies. Typical problems include the Wintel bias, too much coverage of software application tools and too little of computer science concepts, too many technical terms, meaningless analogies and examples, lack of supplementary materials, and inadequate treatment of programming-related content. The discussion about each problem is substantiated with examples, and suggestions are made on possible improvement. This analysis should help textbook writers avoid undesirable elements in their books and help high school computer teachers select higher quality books for their students.     

Using message framing to promote acceptance of the human papillomavirus vaccine.

Objective: Use of message framing for encouraging vaccination, an increasingly common preventive health behavior, has received little empirical investigation. The authors examined the relative effectiveness of gain-versus loss-framed messages in promoting acceptance of a vaccine against human papillomavirus (HPV)-a virus responsible for virtually all cases of cervical cancer. Design: Undergraduate women (N = 121) were randomly assigned to read a booklet describing the benefits of receiving (gain-framed message) or the costs of not receiving (loss-framed message) a prophylactic HPV vaccine. After reading the booklet, participants indicated their intent to obtain the HPV vaccine. Main Outcome Measure: A 5-item composite representing intentions to obtain the HPV vaccine. Results: The effect of message framing on HPV vaccine acceptance was moderated by risky sexual behavior and approach avoidance motivation. A loss-framed message led to greater HPV vaccination intentions than a gain framed message but only among participants who had multiple sexual partners and participants who infrequently used condoms. The loss-frame advantage was also observed among participants high in avoidance motivation. Conclusion: Findings highlight characteristics of the message recipient that may affect the success of framed messages promoting vaccine acceptance. This study has practical implications for the development of health communications promoting vaccination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In Planta Response of Arabidopsis to Photothermal Impact Mediated by Gold Nanoparticles

Biological responses to photothermal effects of gold nanoparticles (GNPs) have been demonstrated and employed for various applications in diverse systems except for one important class – plants. Here, the uptake of GNPs through Arabidopsis thaliana roots and translocation to leaves are reported. Successful plasmonic nanobubble generation and acoustic signal detection in planta is demonstrated. Furthermore, Arabidopsis leaves harboring GNPs and exposed to continuous laser or noncoherent light show elevated temperatures across the leaf surface and induced expression of heat‐shock regulated genes. Overall, these results demonstrate that Arabidopsis can readily take up GNPs through the roots and translocate the particles to leaf tissues. Once within leaves, GNPs can act as photothermal agents for on‐demand remote activation of localized biological processes in plants.     

Machine learning: A tool to support usability?

One problem facing designers of interactive systems is catering to the wide range of users who will use a particular application. Understanding the user is critical to designing a usable interface. There are a number of ways of addressing this problem, including improved design methodologies using ''intuitive'' interface styles, adaptive interfaces, and better training and user support materials. In this article, we argue that each of these solutions involves pattern recognition in one form or another and that machine learning can therefore aid designers of interactive systems in these areas. We report on experiments that demonstrate the potential of machine learning to user modeling that has application to two of these areas in particular: adaptive systems and design methodologies.     

Past and present technocratic solutions to teaching literacy: implications for New Zealand primary teachers and literacy programmes

The late 1990s have seen a resurgence of the arguments for a skills-focused literacy instruction programme. This article explores the New Zealand-based public and professional debates surrounding the promotion of a technocratic approach to literacy instruction during the 1940s and 1950s, and the reoccurrence of the reading debate in late 1990s. In the early stages of both literacy crises, the professional competency of education officials and primary teachers was attacked by business interests and their political allies. The aftermath of the earlier crisis highlights the failure of this mechanistic and 'culture neutral' view of literacy instruction to cater for Maori children. The outcomes of the earlier debate signals a need avoid a similar conclusion to the current debate by adopting a broader approach to literacy instruction in the new millennium if language and literacy instruction programmes are to cater for complex cultural contexts, and the changing technological environments     

Planning for Areas Adjacent to National Parks in Victoria

Threats to national parks from development outside their boundaries are increasing especially on the urban fringe. This article examines the threats in Victoria and the USA. It looks at what has been done so far by town planners in Victoria to combat these threats. Various measures such as the use of siting and design guidelines, conservation covenants and agreements, zoning controls and the role of state and local government legislation are discussed. The article goes on to suggest what could be done. It discusses the importance of having buffer zones around parks in which the Department of Conservation and Natural Resources would become a statutory referral authority. The problems of defining the buffer zone and administering it are also discussed. The author calls for more co-operation between state and local government authorities to reduce these threats. How America handles these threats is also mentioned.     

Immuno-SEM characterization of developing bovine cartilage

Collagen is a vital material in the tissues of living organisms. Found almost everywhere in the human body, collagen is important in connective tissues, bone growth, and cartilage. Collagen XI makes up a very small portion of the cartilaginous tissue; however, it plays a key role in cartilaginous tissue. Collagen XI and two collagen XI isoforms, V1b and V2, are critical in the ossification process. The location of collagen XI, V1b, V2, and their specific functions in the ossification process within developing bovine cartilage are not well characterized. In this work, the location of collagens I, II, XI and two collagen XI isoforms, V1b and V2, present in developing bovine cartilage are investigated using the immuno-SEM technique. The results for the locations of collagen I and II indicate a high level of consistency with previous work, thus showing that the technique of immuno-SEM can be used with confidence to determine the location of various collagen types within cartilaginous and mineralized tissue. This work has shown that collagen XI is present in the lower hypertrophic region and also in a pericellular arrangement, within about two microns of cell walls, throughout the cartilaginous tissue. V1b is expressed in the articular surface, mineralized region, resting zone, and the distal edge of the diaphysis. The V2 isoform is most strongly expressed in areas of newly forming cartilage, and disappears with chondrocyte maturation. V2 is present in the distal edge of the epiphysis, as well as in mineralized tissue. Collagen XI and two of its isoforms, V1b and V2, are thought to play a critical role in the ossification process. However, this role is not well understood, and is still being characterized. The detection of collagen XI and two of its isoforms in the osteo-chondral junction as well as at a joint surface further point to collagen XI, V1b, and V2 playing a vital role in the ossification process, and warrants further research as to their specific function within the ossification process.     

黄民奇：这是“制程工业”!

从代理、到自己投入半导体尖端制程设备研发，汉辰科技董事长黄民奇，日前在捐赠先进半导体制程设备予台湾国研院奈米组件实验室的仪式后，很多人都说，半导体尖端制程设备研发是精密机械工业，但他认为，应该称之为“制程工业”才对!