Effect of an oxygen plasma treatment on the specific surface of platinum electrodeposits for fuel cells

Fuel cells involve electrochemical reactions often catalysed by platinum whose surface has to be maximized. In this paper, platinum nano-particles are deposited onto graphite by a potentiostatic reduction of a dilute 1.0 mM solution of hexachloroplatinate acid. Some samples are pre-treated by highly dissociated oxygen plasma and exhibit an increase of their specific surface compared to the untreated ones. The gain factor on specific surface reaches 3.6 and even 4.4 when the plasma treatment is coupled with the impregnation technique. Surface functionalization made by the plasma treatment lead to denser deposits thanks to an organized nucleation and growth of platinum nuclei. XPS analyses suggest the existence of C–O bonds in the platinum clusters. Although the testing conditions were not optimized, we have measured the performances of a microfuel cell made with the optimized catalyst. The Scharifker and Hills electrocrystallisation model was used to fit the current transients. Untreated samples transients were correctly fitted by the model whereas plasma treated samples transients did not have the requested shape for this model. Hence, nucleation mechanism was determined and confirmed by observation on untreated samples only. The calculated value of the diffusion coefficient of the Pt(IV) anion PtCl₆²⁻ determined by the Cottrell theory was close to the literature, i.e. 2.6 ± 0.6 × 10⁻⁶ cm² s⁻¹.     

Transfer Printing Techniques for Materials Assembly and Micro/Nanodevice Fabrication

Transfer printing represents a set of techniques for deterministic assembly of micro‐and nanomaterials into spatially organized, functional arrangements with two and three‐dimensional layouts. Such processes provide versatile routes not only to test structures and vehicles for scientific studies but also to high‐performance, heterogeneously integrated functional systems, including those in flexible electronics, three‐dimensional and/or curvilinear optoelectronics, and bio‐integrated sensing and therapeutic devices. This article summarizes recent advances in a variety of transfer printing techniques, ranging from the mechanics and materials aspects that govern their operation to engineering features of their use in systems with varying levels of complexity. A concluding section presents perspectives on opportunities for basic and applied research, and on emerging use of these methods in high throughput, industrial‐scale manufacturing.     

Influence of soil moisture content on spectral reflectance of bare soils in the 0.4–14 μm domain

A new semi-empirical soil model simulating the spectral signatures of bare soils in the optical domain 0.4–14 μm according to surface moisture content variation is presented and applied to several databases. The model specification is based on laboratory spectral reflectance measurements of many bare soils at different moisture contents. The measurement analysis leads to the definition of groups of bare soil samples according to their spectral behaviours. These laboratory measurements are made also to characterize the impact of soil moisture on spectral signatures (reflectance levels increasing with moisture content) and to give information on absorption peaks related to soil mineral components (hydroxyl, carbonate, and quartz). The procedure of modelling the spectral signatures of bare soil groups according to moisture content is discussed. The model is applied to a laboratory reflectance database and to the data available in the literature. The spectral reflectances, estimated with a semi-empirical model, compare favourably with reflectance observations.     

Effects of Speech Recognition Accuracy on the Performance of DARPA Communicator Spoken Dialogue Systems

The DARPA Communicator program explored ways to construct better spoken-dialogue systems, with which users interact via speech alone to perform relatively complex tasks such as travel planning. During 2000 and 2001 two large data sets were collected from sessions in which paid users did travel planning using the Communicator systems that had been built by eight research groups. The research groups improved their systems intensively during the ten months between the two data collections. In this paper, we analyze these data sets to estimate the effects of speech recognition accuracy, as measured by Word Error Rate (WER), on other metrics. The effects that we found were linear. We found correlation between WER and Task Completion, and that correlation, unexpectedly, remained more or less linear even for high values of WER. The picture for User Satisfaction metrics is more complex: we found little effect of WER on User Satisfaction for WER less than about 35 to 40% in the 2001 data. The size of the effect of WER on Task Completion was less in 2001 than in 2000, and we believe this difference is due to improved strategies for accomplishing tasks despite speech recognition errors, which is an important accomplishment of the research groups who built the Communicator implementations. We show that additional factors must account for much of the variability in task success, and we present multivariate linear regression models for task success on the 2001 data. We also discuss the apparent gaps in the coverage of our metrics for spoken dialogue systems.     

Considering situational and dispositional approaches to rational self-interest: An extension and response to De Dreu (2006).

The authors respond to C. K. W. De Dreu's (2006; see record 2006-20695-004) critique of their article (B. M. Meglino & M. A. Korsgaard, 2004; see record 2004-21169-004) published in the special section on Theoretical Models and Conceptual Analyses of the Journal of Applied Psychology. They maintain that De Dreu misinterprets their definitions and the psychological processes they addressed and thus raises a number of issues that are not relevant to their model. Meglino and Korsgaard's model focuses on the distinction between rational self-interest and other orientation, whereas the approach taken by De Dreu focuses on the distinction between rational self-interest and collective rationality. In this response, the authors clarify this distinction, address discrepancies between these two approaches, consider the effect of goals and rationality on other orientated behavior, and suggest directions for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Patterns of growth in verbal abilities among children with autism spectrum disorder.

Verbal skills were assessed at approximately ages 2, 3, 5, and 9 years for 206 children with a clinical diagnosis of autism (n = 98), pervasive developmental disorders-not otherwise specified (PDD-NOS; n = 58), or nonspectrum developmental disabilities (n = 50). Growth curve analyses were used to analyze verbal skills trajectories over time. Nonverbal IQ and joint attention emerged as strong positive predictors of verbal outcome. The gap between the autism and other 2 groups widened with time as the latter improved at a higher rate. However, there was considerable variability within diagnostic groups. Children with autism most at risk for more serious language impairments later in life can be identified with considerable accuracy at a very young age, while improvement can range from minimal to dramatic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New results on serial concatenated and accumulated-convolutional turbo code performance

Previous methods for analyzing serial concatenated turbo codes employing union error bounds are extended to determine the complete output weight enumeration function of the code; this provides the opportunity to employ a more refined bound due to Polytrev, with considerably improved results limited, however, to block lengths of about 256 bits by computational constraints. The method is then applied to a new class of “accumulated-convolutional” codes, which is a simple special subclass of serial concatenated codes inspired by the “repeat-accumulate” codes of Divsalar et al. Performance appears to be superior to that of conventional codes and results are obtained for much longer block lengths, with impressive results in regions approaching channel capacity.     

媒体融合凭添信息处理复杂性新一代网络搜索引擎应运而生

如今,网络设备设计人员正面临着各种各样的挑战。其中最主要的挑战是语音、视频和数据的融合。虽然这种融合具有开发新应用的机会和开发规模经济的优势,但要对网络设备中的不同类型的媒体流量进行区分,并将特定的优先级分配给每个类型仍是一个复杂的任务。……     

The validity and reliability of the Violence Risk Scale-Sexual Offender version: Assessing sex offender risk and evaluating therapeutic change.

The Violence Risk Scale-Sexual Offender version (VRS-SO) is a rating scale designed to assess risk and predict sexual recidivism, to measure and link treatment changes to sexual recidivism, and to inform the delivery of sexual offender treatment. The VRS-SO comprises 7 static and 17 dynamic items empirically or conceptually linked to sexual recidivism. Dynamic items with higher ratings identify treatment targets linked to sexual offending. A modified stages of change model assesses the offender's treatment readiness and change. File-based VRS-SO ratings were completed on 321 sex offenders followed up an average of 10 years postrelease. VRS-SO scores predicted sexual and nonsexual violent recidivism postrelease and demonstrated acceptable interrater reliability and concurrent validity. A factor analysis of the dynamic items generated 3 factors labeled Sexual Deviance, Criminality, and Treatment Responsivity, all of which predicted sexual recidivism and were differentially associated with different sex offender types. The dynamic items together made incremental contributions to sexual recidivism prediction after static risk was controlled for. Positive changes in the dynamic items, measured at pre- and posttreatment, were significantly related to reductions in sexual recidivism after risk and follow-up time were controlled for, suggesting that dynamic items are indeed dynamic or changeable in nature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of docosapentaenoic acid on neuronal apoptosis

We previously established that n−3 FA status in membrane phospholipids influences the biosynthesis and accumulation of PS in neuronal tissues. We also demonstrated that neuronal apoptosis under adverse conditions is prevented by DHA enrichment in a PS-dependent manner. In this study, we examined the effect of a structural analog of DHA, docosapentaenoic acid (22∶5n−6, DPA), which accumulates in neuronal membranes during n−3 FA deficiency. We observed that enrichment of neuronal cells with DPA increased the total PS content in comparison to nonenriched control. However, the increase was significantly less than that observed in DHA-enriched cells, primarily due to the fact that the 18∶0,22∶5n−6 species was not accumulated as effectively as 18∶0,22∶6n−3 in PS. As was the case with DHA, DPA enrichment also protected against cell death induced by staurosporine treatment in Neuro 2A cells, but to a lesser extent. These data indicate that provision of DPA in place of DHA is sufficient neither for fully supporting PS accumulation nor for cell survival. The in vitro interaction between Raf-1 and membrane was affected not only by the PS content but also by the fatty acyl composition in PS. The reduction of PS concentration as well as the substitution of 18∶0,22∶6 with 16∶0,18∶1 in the liposome considerably reduced the interaction with Raf-1. These data suggest that depletion of DHA from neuronal tissues may have a compounding effect on Raf-1 translocation in growth factor signaling. The fact that DPA cannot fully support the protective role played by DHA may provide a basis for the adverse effect of n−3 FA deficiency on neuronal development and function.