Role of a stimulus filling an action-outcome delay in human judgments of causal effectiveness

Experiments examined the effect of a stimulus filling a response-outcome delay on human judgments of causal effectiveness. In Experiment 1, subjects rated the effectiveness of 2 concurrently available responses. One response led to the outcome with a 75% probability, the other never led to the outcome. Ratings were higher for the former compared to the latter key, and for immediate compared to delayed outcomes. A signal presented during the delay ameliorated this deficit. Experiments 2 and 3 examined conditioned reinforcement and perceptual catalysis accounts of this effect. In both experiments, 50% of responses on each of 2 keys led to an outcome. Ratings were high, relative to an unsignaled condition, when a stimulus filled the outcome delay, and when the same stimulus followed the response but did not precede the outcome. This result is not consistent with the operation of perceptual catalysis and was shown to be the result of secondary-reinforcement-like processes rather than outcome-confusion or generalization between responses (Experiments 3, 4).     

The effects of surface oxidation on luminescence of nano diamonds

In this work we quantify and characterise the effects of air-oxidation on nitrogen-vacancy defect luminescence in both high-temperature-high-pressure and detonation synthesized nanodiamonds using Raman and luminescence spectroscopies. We find that oxidation treatments result in an increased nitrogen-vacancy centre excited state lifetime from 13 ns to 25 ns and in 5-nm diamonds the intensity of this luminescence increases by at least 5-fold. At the same time, in 5-nm diamonds, short lived surface-defect related luminescence is reduced by 10-fold. Furthermore we find that air oxidation reduces the sp² and disordered carbon fraction of nanodiamonds by up to 5-fold in 5-nm nanodiamonds. Based on these results, the authors suggest that the disordered-carbon and graphite shell of 5-nm nanodiamonds quenches nitrogen-vacancy luminescence, and that this quenching can be partially reduced by surface oxidation. These findings provide useful insights into the role of the graphite and disordered carbon shell in quenching luminescence, and have implications for the applicability of 5-nm nanodiamonds to bio- and quantum physics applications.     

Fabrication of air-channel structures for microfluidic,microelectromechanical, and microelectronic applications

A method is presented for fabricating micro-air-channel structures encapsulated by a dielectric material using a sacrificial polymer based on polynorbornene (PNB) chemistry. A spin-coated film of PNB was patterned to define the exact geometry of the air-channels using conventional lithographic and etching techniques. The sacrificial polymer was encapsulated with a permanent dielectric material. The composite was then raised to elevated temperatures to produce gaseous products which permeate through the encapsulating material (SiO₂ , SiN_x or other polymer) leaving behind minimal solid residue. Air-channels integrated with metal interconnections can be formed via a Damascene, or in-lay process. After patterning the sacrificial polymer, copper was electroplated, followed by encapsulation with the dielectric. Various issues pertaining to the processing steps have been investigated and are discussed, such as type of encapsulants, feasible air-channel sizes, and processing conditions. Such air-channel structures are believed to have potential applications in microelectronics, displays, printers, multilevel wiring boards, microscale chemical reactors on a chip, and microelectromechanical devices     

Schedules of reinforcement as determinants of human causality judgments and response rates.

Experiments examined the effect of relationships between a response and an outcome on human judgments of causal effectiveness. In Experiment 1, the time between outcomes obtained on a variable ratio (VR) schedule became the intervals for a yoked variable interval (VI) schedule. Response rates were higher on the VR than on the VI schedule. In Experiment 2, the number of responses required per outcome on a VR schedule were matched to that on a master VI 20-s schedule. Both ratings of causal effectiveness and response rates were higher in the VR schedule. In Experiment 3, tandem VI fixed-ratio (FR) schedules produced higher rates and judgments than equivalent conjunctive VI FR schedule. In Experiment 4, a VI schedule with a reinforcement requirement for a short interresponse time (IRT) produced higher rates and judgments than a simple VI schedule. These results corroborate the view that schedules are a determinant of both response rates and causal judgments. Few current theories of causal judgment predict this pattern of results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Home-based, interactive videoconferencing for adolescents with epilepsy and their families.

Context: Home-based videoconferencing may be a promising vehicle for providing much-needed counseling services to at-risk adolescents with epilepsy and their families. However, there has been only limited research examining differences in user perceptions of telecommunication-mediated counseling versus traditional, office-based counseling. Objective: To examine differences between the perceptions of adolescents with epilepsy and their parents in regard to comfort, distraction, and therapeutic alliance across 3 different modalities: (a) home-based video-system counseling, (b) home-based speakerphone counseling, and (c) videotaped, office-based counseling. Results: Mothers and adolescents reported moderately high levels of comfort and therapeutic alliance and low levels of distraction across all modalities. Adolescents were more comfortable and less distracted than their mothers across all three conditions. Conclusions: These results lend preliminary support to the use of telecommunication-mediated counseling with at-risk adolescents with epilepsy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

NeXOS – The design,development and evaluation of a rehabilitation system for the lower limbs

Recent years have seen the development of a number of automated and semi-automated systems to support physiotherapy and rehabilitation. These deploy a range of technologies from highly complex purpose built systems to approaches based around the use of industrial robots operating either individually or in combination for applications ranging from stroke rehabilitation to mobility enhancement. The NeXOS project set out to investigate an approach to the rehabilitation of the lower limbs in a way which brought together expertise in engineering design and mechatronics with specialists in rehabilitation and physiotherapy.The result is prototype of a system which is potentially capable in operating in a number of modes from fully independent to providing direct support to a physiotherapist during manipulation of the limb. Designed around a low cost approach for an implementation ultimately capable of use in a patients home using web-based strategies for communication with their support team, the prototype NeXOS system has validated the adoption of an integrated approach to its development. The paper considers this design and development process and provides the results from the initial tests with physiotherapists to establish the operational basis for clinical implementation.     

What makes a video go viral? An analysis of emotional contagion and Internet memes

What qualities lead some Internet videos to reach millions of viewers while others languish in obscurity? This question has been largely unexamined empirically. We addressed this issue by examining the role of emotional response and video source on the likelihood of spreading an Internet video by validating the emotional response to an Internet video and investigating the underlying mechanisms. Results indicated that individuals reporting strong affective responses to a video reported greater intent to spread the video. In terms of the role of the source, anger-producing videos were more likely to be forwarded but only when the source of the video was an out-group member. These results have implications for emotional contagion, social influence, and online behavior.     

Effect of an ultraviolet/ozone treatment on the surface texture and functional groups on polyacrylonitrile carbon fibres

The effect of an ultraviolet generated ozone treatment (UV/O₃), on the surface and near surface functionality and structure of polyacrylonitrile based carbon fibres has been studied using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, and Raman spectroscopy. Results were compared to electrochemically treated fibres. The UV/O₃ treated fibres showed increased levels of oxygen functionalities. Levels of oxygen comparable to a high level electrochemical shear treatment were achieved within 5 min of treatment (O/C 0.11 ± 0.03 for both treatments). XPS O1s/C1s ratios as high as 0.3 were produced, with saturation occurring at approximately 40 min exposure. The main functional groups introduced were, in addition to hydroxyl species, alkoxides (ca. 286.5 eV), carbonyl (288.0 eV), and carboxyl (289.5 eV). Examination of the full width half maximum of the graphite peak from XPS C1s showed some disorder was introduced to the first few layers of the fibre with treatment but the effect was not evident in the Raman, i.e. in the bulk of the fibre.