Adaptive disk spin‐down for mobile computers

We address the problem of deciding when to spin down the disk of a mobile computer in order to extend battery life. One of the most critical resources in mobile computing environments is battery life, and good energy conservation methods increase the utility of mobile systems. We use a simple and efficient algorithm based on machine learning techniques that has excellent performance. Using trace data, the algorithm outperforms several methods that are theoretically optimal under various worstcase assumptions, as well as the best fixed timeout strategy. In particular, the algorithm reduces the power consumption of the disk to about half of the energy consumed by a one minute fixed timeout policy. Furthermore, the algorithm uses as little as 88% of the energy consumed by the best fixed timeout computed in retrospect.     

Short‐Wavelength Lasing‐Spasing and Random Spasing with Deeply Subwavelength Thin‐Film Gain Media

Lasing‐spasers are subwavelength‐sized metal/dielectric structures that emit light via stimulated emission of surface plasmons. Here, it is demonstrated that silver nanoparticles combined with deeply subwavelength, blue‐emitting conjugated polymer thin films can function as room‐temperature lasing‐spasers and random spasers with quality factors up to 250. In contrast to other thin‐film‐based spaser and plasmonic random laser studies, which have used gain films ranging from ≈200 nm to 500 nm in thickness and which monitor emission guided to the sample edges, in this study, the thickness of the thin‐film gain medium ranges from 30 nm to 70 nm and emission is collected normal to the plane of the film. This eliminates effects that arise from optical trapping of scattered emission within the gain medium that is typically associated with plasmonic random lasing. The use of the conjugated polymer thin‐film gain medium allows higher chromophore densities compared to organic dye‐doped layers, which enables spasing using deeply subwavelength gain layers. Samples implementing gold nanoparticles and the conjugated polymer gain medium do not exhibit stimulated emission, demonstrating that it is the spectral overlap between the silver nanoparticle's surface plasmon resonance and the gain medium's emission that is necessary for observation of stimulated emission from this material system.     

Emissions and energy efficiency assessment of baseload wind energy systems

The combination of wind energy generation and energy storage can produce a source of electricity that is functionally equivalent to a baseload coal or nuclear power plant. A model was developed to assess the technical and environmental performance of baseload wind energy systems using compressed air energy storage. The analysis examined several systems that could be operated in the midwestern United States under a variety of operating conditions. The systems can produce substantially more energy than is required from fossil or other primary sources to construct and operate them. By operation at a capacity factor of 80%, each evaluated system achieves an effective primary energy efficiency of at least five times greater than the most efficient fossil combustion technology, with greenhouse gas emission rates less than 20% of the least emitting fossil technology currently available. Life-cycle emission rates of NOx and SO2 are also significantly lower than fossil-based systems.     

The Irish organic food market: shortfalls, opportunities and the need for research

In 2009 the Irish organic food market was forecasted to grow from €120 m to €239 m by 2013; however, recent figures set its value at just €90 m. An estimated 70% of this market is imported. Surveys of Irish consumers reveal that 66% of consumers prefer to buy local produce and most organic consumers are buying organic at supermarkets. This evidence reveals that Irish producers must trade at supermarkets, and promote ‘local produce’ to ensure their produce reach the majority of buyers. Seventy‐eight % of organic rejecters state price and 21% state unawareness of the benefits as reasons for not buying organic. Many Irish consumers are buying organic food on the perceived belief that it is healthier, safer and tastes better; however, a review of studies on organic versus conventional foods in terms of health benefits, safety and sensory quality has shown that existing data is limited in scope and fails to show a clear trend. The review concludes with the need for a comprehensive study of a range of organic and conventional foods available to the Irish consumer in order to determine if differences in organic cultivation result in statistically significant differences in health linked compounds and sensory quality. Copyright © 2011 Society of Chemical Industry     

Looking inside the Russian doll: the interconnections between context, learning and pedagogy in the workplace

There is now much awareness of the symbiotic relationship between workplace learning, the organisation of work, level of employee involvement, organisational performance, and the broader economic, regulatory, and social context within which organisations have to operate. This article argues that we have to identify and take serious account of the contextual factors (external and internal) that affect all organisations, as these are central to developing our understanding of the nature of pedagogical practice within any workplace setting. By closely examining the nature and impact of these contextual factors, we can gain greater insight into the phenomenon of why organisations adopt different practices and why they create such different learning environments. The article draws on emerging findings from an ESRC-funded multisector study in the UK and uses illustrations from two contrasting sectors to highlight the impact of context on pedagogical practice.     

The bilevel structure of the Outcome Questionnaire–45.

The structure of the Outcome Questionnaire–45 (Lambert et al., 2001) was examined in a sample of 1,100 university counseling center clients using confirmatory factor analysis. Specifically, the relative fit of 1-factor, 3-factor orthogonal, 3-factor oblique, 4-factor hierarchical, and 4-factor bilevel models were examined. Although the 3-factor oblique, 4-factor hierarchical, and 4-factor bilevel models fit the data well, the 4-factor bilevel model fit the data best. The results provided support for the fit of the 4-factor bilevel model where each item loads on 1 of the 3 independent scales of Symptom Distress, Social Role Performance, and Interpersonal Relations, in addition to a nonoverlapping general distress factor. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Iron Homeostasis in the CNS: An Overview of the Pathological Consequences of Iron Metabolism Disruption

Iron homeostasis disruption has increasingly been implicated in various neurological disorders. In this review, we present an overview of our current understanding of iron metabolism in the central nervous system. We examine the consequences of both iron accumulation and deficiency in various disease contexts including neurodegenerative, neurodevelopmental, and neuropsychological disorders. The history of animal models of iron metabolism misregulation is also discussed followed by a comparison of three patients with a newly discovered neurodegenerative disorder caused by mutations in iron regulatory protein 2.     

Exploring differences in youth and parent reports of antisociality among adolescent sexual and nonsexual offenders.

This study examined the extent of, and explored several possible explanations for, the discrepancies found between adolescent and parent reports of conduct problems in adolescent sexual and nonsexual offenders. We found that adolescent sexual offenders scored lower on measures of conduct problems than did nonsexual offenders, whether on the basis of adolescent or parent report, though the difference was much larger for parent reports. Examining this discrepancy more closely, we found that parents of sexual offenders reported less antisocial behavior than did their sons, whereas parents of nonsexual offenders reported more antisocial behavior than did their sons. The same pattern of results was obtained for reports on impulsivity, but much less so with respect to antisocial personality traits such as narcissism and callousness. Measures of family functioning were generally not related to these parent–adolescent discrepancies in reports of conduct problems, but these discrepancies were positively correlated with parental reports of stress. The implications of these findings for the interpretation of research on adolescent sexual offenders and comparisons of sexual and nonsexual offenders are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)