The role of sleep in creative task performance

Includes abstract.Includes bibliographical references (leaves 84-91).Anecdotal evidence suggests that sleep can aid in creative performance, but few studies have systematically investigated this association. Prior research suggests that creative thinking, particularly divergent cognition, is similar to mental states found in sleep and dreaming, especially during REM sleep. Studies have found that sleep benefits general learning and problem-solving, and facilitates insight that promotes enhanced performance on cognitive tasks. This study investigated the effects of sleep on performance with verbal and visual tasks that explicitly require creative ability. I hypothesised that participants with a period of sleep between task preparation and execution would perform better than participants with an equal period of REM-deprived sleep, daytime wakefulness, or no interval between preparation and execution, but there would be no difference in performance between the participants in terms of convergent cognition. The study was a 4-level, single-factor design, with state of consciousness as the manipulated variable. Participants (n = 87) were recruited from the university undergraduate population. Participants memorised a wordlist for task preparation and then, after an interval of either normal sleep, REM-deprived sleep, waking activity, or no interval, used the same wordlist to write a creative short story for task execution. The stories were assessed for creativity-related constructs by the researcher and independent raters. Participants also completed a visual design fluency task at both stages of the study, following a 4-level, single-factor, repeated-measures design. Participants' scores on the Torrance Test of Creative Thinking (TTCT) Verbal Edition and the Shipley Institute of Living Scale (SILS) were used to control for general creative ability and IQ respectively. ANCOVA, repeated measures ANOVA, and Fisher's r to z transformation statistics were used to analyse the data. Although generally the hypotheses were not directly supported by the data obtained, trends suggest that there was a connection between sleep and creativity, especially an apparent interaction between baseline creativity and the type of interval. Based on the indirect evidence obtained, directions for future research for investigating sleep and creativity are discussed

Electrochemical processing of single-walled carbon nanotubes and related materials

The remarkable properties of single-walled carbon nanotubes (SWNTs) and potential applications are hindered by current solution-phase processing strategies. The initial dissolution of SWNTs remains a fundamental challenge, reliant on aggressive chemistry or ultrasonication and lengthy ultracentrifugation. In this thesis, a simple non-aqueous electrochemical reduction process that leads to spontaneous dissolution of individualised SWNTs from raw, unprocessed powders is outlined. The intrinsic electrochemical stability and conductivity of these nanoparticles allows their electrochemical dissolution from a pure SWNT cathode to form solutions of well-defined nanoparticle anions with characteristic charge density. Other than a reversible change in redox/solvation state, there is no obvious chemical functionalisation of the structure, suggesting an analogy to conventional atomic electrochemical dissolution. The heterogeneity of as-synthesised SWNT samples leads to the sequential dissolution of distinct fractions over time. Initial preferential dissolution of defective nanotubes and carbonaceous debris provides a simple, non-destructive means to purify raw materials without recourse to the usual, damaging, competitive oxidation reactions. During early stage developments, the process showed remarkable affinity for dissolving metallic SWNTs, providing a potentially scalable route for separation by electronic character, vital for many applications. However, selectivity was lost with significantly increased process yields (complete dissolution) following several optimisations. Subsequently, the electrochemical deposition of SWNTs is proposed as a new route to selectively plate specific SWNT species and avoid unwanted functionalisations that occur when exposing reduced SWNTs to different atmospheres. Finally, the extension of electrochemical processing to related materials including activated and graphitic nanocarbons, metallic and metal chalcogenide nanomaterials was also investigated, with great promise for the development of new applications.Open Acces

Wireless Sensor Networks for Condition Monitoring in the Railway Industry : a Survey

In recent years, the range of sensing technologies has expanded rapidly, whereas sensor devices have become cheaper. This has led to a rapid expansion in condition monitoring of systems, structures, vehicles, and machinery using sensors. Key factors are the recent advances in networking technologies such as wireless communication and mobile adhoc networking coupled with the technology to integrate devices. Wireless sensor networks (WSNs) can be used for monitoring the railway infrastructure such as bridges, rail tracks, track beds, and track equipment along with vehicle health monitoring such as chassis, bogies, wheels, and wagons. Condition monitoring reduces human inspection requirements through automated monitoring, reduces maintenance through detecting faults before they escalate, and improves safety and reliability. This is vital for the development, upgrading, and expansion of railway networks. This paper surveys these wireless sensors network technology for monitoring in the railway industry for analyzing systems, structures, vehicles, and machinery. This paper focuses on practical engineering solutions, principally,which sensor devices are used and what they are used for; and the identification of sensor configurations and network topologies. It identifies their respective motivations and distinguishes their advantages and disadvantages in a comparative review

Implicit Theories of Mental Toughness: Relations With Cognitive, Motivational, and Behavioral Correlates

People differ in their implicit theories about mental toughness, that is, whether they believe this quality is immutable (entity theorists) or changeable (incremental theorists). The aim of this study was to explore whether peoples’ implicit theories of mental toughness are related to cognitive, motivational, and behavioral variables considered as hallmarks of this personal quality. We conducted 3 studies with participants from different achievement contexts: 444 undergraduate students aged 17 to 26 years (M 19.25); 395 employees aged 25 to 79 years (M 48.78); and 230 adolescent athletes aged 11 to 17 years (M 14.98). Students completed a measure of implicit theories of mental toughness, fear of failure, and perceived stress. Employees completed a measure of implicit theories and were rated on performance and creativity by their supervisor. Athletes completed a measure of implicit theories of mental toughness, resilience, and thriving. Across all 3 samples, cluster analyses supported the existence of an incremental theory (high incremental theory, low entity theory) alongside an ambivalent group (moderate scores on both theories). These clusters differed on fear of failure, stress, performance, creativity, resilience, and thriving consistent with theoretical expectations. The current findings suggest that people’s implicit theories of mental toughness may have important implications for understanding cognitive, motivational, and behavioral correlates considered hallmarks of this psychological concept

Probing the charging mechanisms of carbon nanomaterial polyelectrolytes

Chemical charging of single-walled carbon nanotubes (SWCNTs) and graphenes to generate soluble salts shows great promise as a processing route for electronic applications, but raises fundamental questions. The reduction potentials of highly-charged nanocarbon polyelectrolyte ions were investigated by considering their chemical reactivity towards metal salts/complexes in forming metal nanoparticles. The redox activity, degree of functionalisation and charge utilisation were quantified via the relative metal nanoparticle content, established using thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). The fundamental relationship between the intrinsic nanocarbon electronic density of states and Coulombic effects during charging is highlighted as an important area for future research

Empirical Investigations of the Opportunity Limits of Automatic Residential Electric Load Shaping

Residential electric load shaping is often implemented as infrequent, utility-initiated, short-duration deferral of peak demand through direct load control. In contrast, investigated herein is the potential for frequent, transactive, intraday, consumer-configurable load shaping for storage-capable thermostatically controlled electric loads (TCLs) including refrigerators, freezers, and hot water heaters. Unique to this study are 28 months of 15-minute-interval observations of usage in 101 homes in the Pacific Northwest United States that specify start, duration, and usage patterns of approximately 25 submetered loads per home. The magnitudes of the load shift from voluntarily-participating TCL appliances are aggregated to form hourly upper and lower load-shaping limits for the coordination of electrical generation, transmission, distribution, storage, and demand. Empirical data are statistically analyzed to define metrics that help quantify load-shaping opportunities.</p

Quantifying the Opportunity Limits of Automatic Residential Electric Load Shaping

Electric utility residential demand response programs typically do not shape load using intraday, transactive, and local setpoint adjustments of storage-capable thermostatically controlled loads (TCL). In the future, it is envisioned that utilities will continually broadcast forecast dynamic prices of electricity to automatically shape residential load and create load elasticity by alternatively encouraging or discouraging electric energy use. In this research, a binary conditional algorithm was developed and applied to TCL appliance empirical time series data to estimate price-based instantaneous load add and shed opportunities. To overcome limitations of traditional stochastic methods in quantifying diverse, non-normal, non-stationary distributions, recent developments in spectral methods were applied to capture and simulate load in both the frequency and time domains. The performance of autoregressive and spectral reconstruction methods was compared, with phase reconstruction providing the best simulation ensembles. The terminal application of this work is simulating the monetary savings anticipated from wide-scale deployment of price-responsive model predictive control of air conditioning, domestic hot water (DHW) heating, and battery systems.</p

Galactic interstellar 18O/17O ratios - a radial gradient?

(Abridged) Our aim is to determine 18O/17O abundance ratios across the entire Galaxy. These provide a measure of the amount of enrichment by high-mass versus intermediate-mass stars. Such ratios, derived from the C18O and C17O J=1-0 lines alone, may be affected by systematic errors. Therefore, the C18O and C17O (1-0), (2-1), and (3-2), as well as the 13CO (1-0) and (2-1) lines, were observed towards 18 prominent galactic targets (a total of 25 positions). The combined dataset was analysed with an LVG model, accounting for optical depth effects. The data cover galactocentric radii R between 0.1 and 16.9 kpc (solar circle at 8.5 kpc). Near the centre of the Galaxy, 18O/17O = 2.88 +/- 0.11. For the galactic disc out to an R of ca. 10 kpc, 18O/17O = 4.16 +/- 0.09. At ca. R = 16.5 kpc, 18O/17O = 5.03 +/- 0.46. Assuming that 18O is synthesised predominantly in high-mass stars (M > 8 Msun), while C17O is mainly a product of lower-mass stars, the ratio from the inner Galaxy indicates a dominance of CNO-hydrogen burning products that is also apparent in the C- and N-isotope ratios. The high 18O/17O value of the solar system (5.5) relative to that of the ambient ISM suggests contamination by nearby high-mass stars during its formation. High values in the metal-poor environment of the outer Galaxy are not matched by the low values observed towards the even more metal-poor LMC. Apparently, the outer Galaxy cannot be considered as an intermediate environment between the solar neighbourhood and the ISM of small metal-poor galaxies. The apparent 18O/17O gradient along the galactic disc and the discrepancy between outer disc and LMC isotope ratios may be explained by different ages of the respective stellar populations.Comment: Accepted by Astron. & Astroph.; 10 pages + 4 pages on-line material (figs

Orphans and other vulnerable children : what role for social protection ?

Recent estimates have provided unprecedented numbers of orphans, and vulnerable children, either brought about because of the HIV/AIDS epidemic, or carriers themselves of HIV infections, a relentless growth which has precipitated a multifaceted care burden, that will too, grow for the next twenty years. This report records the proceedings of the Conference"Orphans and Other Vulnerable Children", which sought to promote awareness of the extent of this crisis, and, to probe the role of social protection in implementing a balanced response. The social protection framework for working with orphans, and vulnerable children shaped the conference agenda. Provision of appropriate risk management instruments is crucial for lasting poverty reduction, while programs to reduce the vulnerability of orphans, and other children, should play an integral role in any national development strategy, in the context of the HIV/AIDS epidemic. Building community capacity will constitute the centerpiece of any feasible response. Within a realistic framework, programs must spread, and scale up, to address the vast, and growing need.Street Children,Youth and Governance,Health Monitoring&Evaluation,Children and Youth,Primary Education