Enhanced third-order optical nonlinearity of silver nanoparticles with a tunable surface plasmon resonance

Poly(vinylalcohol) (PVA)-stabilized silver nanoparticles were prepared by a seeding method. Nanoparticles of varying morphology were obtained by controlled variation of the reaction conditions, and this method allowed the tailoring of the position of the surface plasmon resonance. The samples show two bands in the visible absorption spectrum: one in the 410-440-nm region and a second peak between 500 and 600 nm. This tunable surface plasmon resonance serves to increase the third-order optical nonlinearity (chi 3) of the nanoparticles (measured at 532 nm) by a factor of 16.     

Relational learning of a size concept.

Administered relational size problems in the context of ordinal series to 72 4-5 yr olds. Solution was facilitated when Ss were directed to locate a terminal member (the smallest) of the series. In contrast, Ss who were instructed to locate a nonterminal member without prior designation of a terminal member were unable to achieve solution of the problem. Age- and sex-related differences in performance were observed as well as differences associated with stimulus arrangements and stimulus sizes. The outcomes are discussed in terms of composite task demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of government actions on technological innovation for SO2 control

The relationship between government actions and innovation in environmental control technology is important for the design of cost-effective policies to achieve environmental goals. This paper examines such relationships for the case of sulfur dioxide control technology for U.S. coal-fired power plants. The study employs several complementary research methods, including analyses of key government actions, technology patenting activity, technology performance and cost trends, knowledge transfer activities, and expert elicitations. Our results indicate that government regulation appears to be a greater stimulus to inventive activity than government-sponsored research support alone, and that the anticipation of regulation also spurs inventive activity. Regulatory stringency focuses this activity along particular technical pathways and is a key factor in creating markets for environmental technologies. We also find that with greater technology adoption, both new and existing systems experience notable efficiency improvements and capital cost reductions. The important role of government in fostering knowledge transfer via technical conferences and other measures is also seen as an important factor in promoting environmental technology innovation.     

Blind deblurring of spiral CT images

To discriminate fine anatomical features in the inner ear, it has been desirable that spiral computed tomography (CT) may perform beyond their current resolution limits with the aid of digital image processing techniques. In this paper, we develop a blind deblurring approach to enhance image resolution retrospectively without complete knowledge of the underlying point spread function (PSF). An oblique CT image can be approximated as the convolution of an isotropic Gaussian PSF and the actual cross section. Practically, the parameter of the PSF is often unavailable. Hence, estimation of the parameter for the underlying PSF is crucially important for blind image deblurring. Based on the iterative deblurring theory, we formulate an edge-to-noise ratio (ENR) to characterize the image quality change due to deblurring. Our blind deblurring algorithm estimates the parameter of the PSF by maximizing the ENR, and deblurs images. In the phantom studies, the blind deblurring algorithm reduces image blurring by about 24%, according to our blurring residual measure. Also, the blind deblurring algorithm works well in patient studies. After fully automatic blind deblurring, the conspicuity of the submillimeter features of the cochlea is substantially improved.     

Genomic mining for complex disease traits with “random chemistry”

Our rapidly growing knowledge regarding genetic variation in the human genome offers great potential for understanding the genetic etiology of disease. This, in turn, could revolutionize detection, treatment, and in some cases prevention of disease. While genes for most of the rare monogenic diseases have already been discovered, most common diseases are complex traits, resulting from multiple gene–gene and gene-environment interactions. Detecting epistatic genetic interactions that predispose for disease is an important, but computationally daunting, task currently facing bioinformaticists. Here, we propose a new evolutionary approach that attempts to hill-climb from large sets of candidate epistatic genetic features to smaller sets, inspired by Kauffman’s “random chemistry” approach to detecting small auto-catalytic sets of molecules from within large sets. Although the algorithm is conceptually straightforward, its success hinges upon the creation of a fitness function able to discriminate large sets that contain subsets of interacting genetic features from those that don’t. Here, we employ an approximate and noisy fitness function based on the ReliefF data mining algorithm. We establish proof-of-concept using synthetic data sets, where individual features have no marginal effects. We show that the resulting algorithm can successfully detect epistatic pairs from up to 1,000 candidate single nucleotide polymorphisms in time that is linear in the size of the initial set, although success rate degrades as heritability declines. Research continues into seeking a more accurate fitness approximator for large sets and other algorithmic improvements that will enable us to extend the approach to larger data sets and to lower heritabilities.     

The who and the what of usage of two cancer online communities

The explosion of use of Internet-based communication for health requires attention to the ways survivors of specific diseases and those close to them participate in using resources. This research focuses on two cancer groups – breast and prostate – and how they use WebMD asynchronous bulletin boards. Four hundred and eighty two messages were coded for communicator (survivors, spouses, others) and content of messages. Most common communicators were survivors, but the two groups differed in percentages of communicator. Of four main categories of content – medical/treatment, intimacy/sexuality, emotional expression, and support – most common were support and medical/treatment. The groups differed significantly on those four categories, with breast cancer more support-dominated and prostate more medical/treatment-dominated and more intimacy/sexuality messages. There were no group differences in emotional-toned vs. social support seeking vs. providing support, or positive vs. negative emotions expressed. Generally, there was considerable commonality, and the differences found primarily supported gender-specific notions of communication and need.     

Further explorations of perceptual speed abilities in the context of assessment methods, cognitive abilities, and individual differences during skill acquisition.

Measures of perceptual speed ability have been shown to be an important part of assessment batteries for predicting performance on tasks and jobs that require a high level of speed and accuracy. However, traditional measures of perceptual speed ability sometimes have limited cost-effectiveness because of the requirements for administration and scoring of paper-and-pencil tests. There have also been concerns about the validity of previous computer approaches to administering perceptual speed tests (e.g., see Mead & Drasgow, 1993). The authors developed two sets of computerized perceptual speed tests, with touch-sensitive monitors, that were designed to parallel several paper-and-pencil tests. The reliability and validity of the tests were explored across three empirical studies (N = 167, 160, and 117, respectively). The final study included two criterion tasks with 4.67 and 10 hours of time-on-task practice, respectively. Results indicated that these new measures provide both high levels of reliability and substantial validity for performance on the two skill-learning tasks. Implications for research and application for computerized perceptual speed tests are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Researching haptics in higher education: The complexity of developing haptics virtual learning systems and evaluating its impact on students’ learning

hapTEL, an interdisciplinary project funded by two UK research councils from 2007 to 2011, involves a large interdisciplinary team (with undergraduate and post-graduate student participants) which has been developing and evaluating a virtual learning system within an HE healthcare education setting, working on three overlapping strands. Strand 1 involves the technical development and evaluation of the hapTEL workstation which simulates clinical conditions for dental training including haptics (sense of touch). Strand 2 involves examining the traditional undergraduate curriculum and how this could benefit from the use of haptics. Strand 3 is concerned with the educational evaluation of the impact of the work carried out within Strands 1 and 2. Two theoretical frameworks (Entwistle, (1987) and Webb and Cox (2004)) have been used to identify as many factors as possible which could affect the impact of Technology Enhanced Learning (TEL) on the quality of the learning achieved. These frameworks have formed a foundation for measuring the impact of TEL on curriculum change, teachers’ pedagogical practices, students’ learning and on institutional practices. A range of quantitative and qualitative methods were designed, piloted and evaluated in order to measure the impact of TEL on teaching and learning; and to have a rich and robust data set which also addresses the variables in the frameworks. The results from using these frameworks show that institutional and departmental factors should be considered when evaluating the impact of TEL in higher education and that these had a major influence on the design and curriculum integration of the hapTEL systems. We have also shown that by involving the end users from the beginning enabled not only an enhancement of the students’ learning experiences but also a modification to the traditional curriculum itself and the successful integration of TEL within a very traditional undergraduate higher education dental curriculum. The conclusions from this paper confirm earlier reviews of researching TEL that technology integration is extremely complex and the related research requires a comprehensive approach of both quantitative and qualitative methods if one is to take account of the range of variables identified by theoretical frameworks. Finally, repeating the range of empirical investigations for a second year enables researchers to validate the effectiveness of the methods used in the initial year and thereby maximise the reliability and generalisability of the research outcomes.