PCCP does exist

Neutral and cationic \[C-2,P-2] were investigated by a combination of mass spectrometry and electronic structure calculations. The cationic \[C-2,P-2](.+) potential energy surface including all relevant minima, transition states and fragmentation products was calculated at the B3LYP/6-311G(3df) level of theory. The most stable structures are linear PCCP.+ 1(.+) (E-rel=0 kcal mol(-1)), a three-membered ring with exocyclic phosphorus c-(PCC)-P 2(.+) (E-rel = 40.8 kcal mol(-1)), and the rhombic isomer 3(.+) (E-rel = 24.9 kcal mol(-1)). All fragmentation channels are significantly higher in energy than any of the \[C-2,P-2](.+) isomers. Experimentally, \[C-2,P-2](.+) ions are generated under high vacuum conditions by electron ionization of two different precursors. The fragmentation of \[C-2,P-2](.+) on collisional activation is preceded by rearrangement reactions which obscure the structural connectivity of the ions. The existence and the high stability of neutral \[C-2,P-2] were proved by a neutralization-reionization (NR) experiment. Although an unambiguous structural assignment of the neutral species cannot be drawn, both theory and experiment suggest that the long-sought neutral, linear PCCP 1 is generated using the NR technique.

Hybrid genetic algorithm for elimination of severe stress concentration in railhead ends

This paper presents a computational method for eliminating severe stress concentration at the unsupported railhead ends in rail joints through innovative shape optimization of the contact zone, which is complex due to near field nonlinear contact. With a view to minimizing the computational efforts, hybrid genetic algorithm method coupled with parametric finite element has been developed and compared with the traditional genetic algorithm (GA). The shape of railhead top surface where the wheel contacts nonlinearly was optimized using the hybridized GA method. Comparative study of the optimal result and the search efficiency between the traditional and hybrid GA methods has shown that the hybridized GA provides the optimal shape in fewer computational cycles without losing accuracy. The method will be beneficial to solving complex engineering problems involving contact nonlinearity.

Service encounter needs theory : a dyadic, psychosocial approach to understanding service encounters

Interactions between customers and service providers are ubiquitous. Some of these encounters are routine, but many are characterized by conflict and intense emotions. This chapter introduces a new theory, service encounter needs theory (SENT) that aims to elucidate the mechanisms through which service encounter behaviors affect outcomes for customers and employees. Evidence is presented for the preeminence within these encounters of eight psychosocial needs, and propositions are advanced regarding likely antecedents to fulfillment and violation of these needs. Emotional experiences and displays are viewed as important consequences of need fulfillment and violation, as are numerous cognitive, behavioral, and health-related outcomes.

When leadership meets organizational change : the influence of the top management team and supervisory leaders on change appraisals, change attitudes, and adjustment to change

Despite the importance of adaption and change for firm survival, the failure rate of organizational change efforts remains alarmingly high (Beer and Nohria, 2000; Kotter, 1995). In a recent global survey of over 3,000 executives,Meaney and Pung (2008) reported that two-thirds of executives indicated that their firm had failed to successfully implement organizational changes. Similarly, academic researchers have also concluded that difficulties in implementing and managing organizational change efforts often precipitate organizational crises (Probst and Raisch, 2005). As a result, attention has been directed to identify the factors that improve the likelihood of successfully implementing organizational change efforts. While there has been practitioner-oriented discussion around the pivotal role of workplace leaders in reducing resistance to change, only a limited number of empirical studies have examined relationships between leader behavior and employee change attitudes (e.g., Bommer, Rich, and Rubin, 2005; Herold, Caldwell, and Liu, 2008; Nemanich and Keller, 2007; Oreg and Berson, 2011). However...

Validity of accelerometry for measurement of activity in people with brain injury

Purpose To evaluate the validity of a uniaxial accelerometer (MTI Actigraph) for measuring physical activity in people with acquired brain injury (ABI) using portable indirect calorimetry (Cosmed K4b(2)) as a criterion measure. Methods Fourteen people with ABI and related gait pattern impairment (age 32 +/- 8 yr) wore an MTI Actigraph that measured activity (counts(.)min-(1)) and a Cosmed K4b(2) that measured oxygen consumption (mL(.)kg(-1.)min(-1)) during four activities: quiet sitting (QS) and comfortable paced (CP), brisk paced (BP), and fast paced (FP) walking. MET levels were predicted from Actigraph counts using a published equation and compared with Cosmed measures. Predicted METs for each of the 56 activity bouts (14 participants X 4 bouts) were classified (light, moderate, vigorous, or very vigorous intensity) and compared with Cosmed-based classifications. Results Repeated-measures ANOVA indicated that walking condition intensities were significantly different (P < 0.05) and the Actigraph detected the differences. Overall correlation between measured and predicted METs was positive, moderate, and significant (r = 0.74). Mean predicted METs were not significantly different from measured for CP and BP, but for FP walking, predicted METs were significantly less than measured (P < 0.05). The Actigraph correctly classified intensity for 76.8% of all activity bouts and 91.5% of light- and moderate-intensity bouts. Conclusions Actigraph counts provide a valid index of activity across the intensities investigated in this study. For light to moderate activity, Actigraph-based estimates of METs are acceptable for group-level analysis and are a valid means of classifying activity intensity. The Actigraph significantly underestimated higher intensity activity, although, in practice, this limitation will have minimal impact on activity measurement of most community-dwelling people with ABI.

Validity of accelerometry in ambulatory children and adolescents with cerebral palsy

To evaluate the validity of the ActiGraph accelerometer for the measurement of physical activity intensity in children and adolescents with cerebral palsy (CP) using oxygen uptake (VO 2) as the criterion measure. Thirty children and adolescents with CP (mean age 12.6 ± 2.0 years) wore an ActiGraph 7164 and a Cosmed K4b 2 portable indirect calorimeter during four activities; quiet sitting, comfortable paced walking, brisk paced walking and fast paced walking. VO 2 was converted to METs and activity energy expenditure and classiWed as sedentary, light or moderate-to-vigorous intensity according to the conventions for children. Mean ActiGraph counts min -1 were classiWed as sedentary, light or moderate-to-vigorous (MVPA) intensity using four diVerent sets of cut-points. VO 2 and counts min¡1 increased signiWcantly with increases in walking speed (P < 0.001). Receiver operating characteristic (ROC) curve analysis indicated that, of the four sets of cut-points evaluated, the Evenson et al. (J Sports Sci 26(14):1557-1565, 2008) cut-points had the highest classiWcation accuracy for sedentary (92%) and MVPA (91%), as well as the second highest classiWcation accuracy for light intensity physical activity (67%). A ROC curve analysis of data from our participants yielded a CP-speciWc cut-point for MVPA that was lower than the Evenson cut-point (2,012 vs. 2,296 counts min¡1), however, the diVerence in classiWcation accuracy was not statistically signiWcant 94% (95% CI = 88.2-97.7%) vs. 91% (95% CI = 83.5-96.5%). In conclusion, among children and adolescents with CP, the ActiGraph is able to diVerentiate between diVerent intensities of walking. The use of the Evenson cut-points will permit the estimation of time spent in MVPA and allows comparisons to be made between activity measured in typically developing adolescents and adolescents with CP. © 2011 Springer-Verlag.

Validation of accelerometry for physical activity measurement in ambulant adolescents with cerebral palsy

Background Promoting participation physical activity (PA) is an important means of promoting healthy growth and development in children with cerebral palsy (CP). The ActiGraph is a uniaxial accelerometer that provides a realtime measure of PA intensity, duration and frequency. Its small, light weight design makes it a promising measure of activity in children with CP. To date no study has validated the use of accelerometry as a measure of PA in ambulant adolescents with CP. Objectives To evaluate the validity of the ActiGraph accelerometer for measuring PA intensity in adolescents with CP, using oxygen consumption (VO2), measured using portable indirect calorimetry (Cosmed K4b2), as the criterion measure. Design Validation Study Participants/Setting: Ambulant adolescents with CP aged 10–16 years, GMFCS rating of I-III. The recruitment target is 30 (10 in each GMFCS level). Materials/Methods Participants wore the ActiGraph (counts/min) and a Cosmed K4b2 indirect calorimeter (mL/kg/min) during six activity trials: quiet sitting (QS), comfortable paced walking (CPW), brisk paced walking (BPW), fast paced walking (FPW), a ball-kicking protocol (KP) and a ball-throwing protocol (TP). MET levels (multiples of resting metabolism) for each activity were predicted from ActiGraph counts using the Freedson age-specific equation (Freedson et al. 2005) and compared with actual MET levels measured by the Cosmed. Predicted and measured METs for each activity trial were classified as light (> 1.5 METs and <4.6 METs) or moderate to vigorous intensity (≥ 4.6 METs). Results To date 36 bouts of activity have been completed (6 participants x 6 activities). Mean VO2 increased linearly as the intensity of the walking activity increased (CPW=9.47±2.16, BPW=14.06±4.38, FPW=19.21±5.68 ml/kg/min) and ActiGraph counts reflected this pattern (CPW=1099±574, BPW=2233±797 FPW=4707±1013 counts/min). The throwing protocol recording the lowest VO2 (TP=7.50±3.86 ml/kg/min) and lowest overall counts/min (TP=31±27 counts/min). When each of the 36 bouts were classified as either light or moderate to vigorous intensity using measured VO2 as the criterion measure, the Freedson equation correctly classified 28 from 36 bouts (78%). Conclusion/Clinical Implications These preliminary findings suggest that there is a relationship between the intensity of PA and direct measure of oxygen consumption and that therefore the ActiGraph may be a promising tool for accurately measuring free living PA in the community. Further data collection of the complete sample will enable secondary analysis of the relationship between PA and severity of CP (GMFCS level).

Crossword puzzle attack on NLS

NLS is one of the stream ciphers submitted to the eSTREAM project. We present a distinguishing attack on NLS by Crossword Puzzle (CP) attack method which is introduced in this paper. We build the distinguisher by using linear approximations of both the non-linear feedback shift register (NFSR) and the nonlinear filter function (NLF). Since the bias of the distinguisher depends on the Konst value, which is a key-dependent word, we present the graph showing how the bias of distinguisher vary with Konst. In result, we estimate the bias of the distinguisher to be around O(2^−30). Therefore, we claim that NLS is distinguishable from truly random cipher after observing O(2^60) keystream words. The experiments also show that our distinguishing attack is successful on 90.3% of Konst among 2^32 possible values. We extend the CP attack to NLSv2 which is a tweaked version of NLS. In result, we build a distinguisher which has the bias of around 2− 48. Even though this attack is below the eSTREAM criteria (2^−40), the security margin of NLSv2 seems to be too low.

Multiple modular additions and crossword puzzle attack on NLSv2

NLS is a stream cipher which was submitted to the eSTREAM project. A linear distinguishing attack against NLS was presented by Cho and Pieprzyk, which was called Crossword Puzzle (CP) attack. NLSv2 is a tweak version of NLS which aims mainly at avoiding the CP attack. In this paper, a new distinguishing attack against NLSv2 is presented. The attack exploits high correlation amongst neighboring bits of the cipher. The paper first shows that the modular addition preserves pairwise correlations as demonstrated by existence of linear approximations with large biases. Next, it shows how to combine these results with the existence of high correlation between bits 29 and 30 of the S-box to obtain a distinguisher whose bias is around 2^−37. Consequently, we claim that NLSv2 is distinguishable from a random cipher after observing around 2^74 keystream words.

An improved gate driver for power MOSFETs using a cascode configuration

To overcome the limitations of existing gate drive topologies an improved gate drive concept is proposed to provide fast, controlled switching of power MOSFETs. The proposed topology exploits the cascode configuration with the inclusion of an active gate clamp to ensure that the driven MOSFET may be turned off under all load conditions. Key operating principles and advantages of the proposed gate drive topology are discussed. Characteristic waveforms are investigated via simulation and experimentation for the cascode driver in an inductive switching application at 375V and 10A. Experimental waveforms compared well with simulations with long gate charging delays (including the Miller plateau) being eliminated from the gate voltage waveform.

Educating for the creative economy in emerging countries

In 1972, the United Nations (UN) Conference on the Human Environment expressed a growing realization that economic and social progress needed to be balanced with a concern for the environment and the stewardship of natural resources. The hard-to-grasp concept of "sustainable development" was first defined as "development that meets the needs of the present without compromising the ability of future generations to meet their needs" (World Commission on Environment and Development [WESDJ, 1987, p. 43). This definition contains two concepts: first, "human needs," with priority given to the world's poor, and, second, the environment's limits for meeting the state of technological and social organization (WESD, 1987, p. 43). At the 2002 World Summit on Sustainable Development (UN, 2002a), the focus on environmental protection broadened to encompass social justice and the fight against poverty as key principles of development that is sustainable. Three interdependent and mutually reinforcing "pillars" were recognized: economic development, social development, and environmental protection. These pillars must be established at local, national, and global levels. The complexity and interrelationship of critical issues such as poverty, wasteful consumption, urban decay, population growth, gender inequality, health, conflict, and the violation of human rights are addressed in all three pillars (Pigozzi, 2003, p. 3). Following the concept of sustainable development, we argue that the challenge for developing countries in contemporary society is to meet the very real need for economic development and opportunities for income generation, while avoiding the unintended and unwanted consequences of economic development and globalization. These consequences include social exclusion, loss of cultural heritage, and environmental and ecological problems.

Charge transport study of high mobility polymer thin-film transistors based on thiophene substituted diketopyrrolopyrrole copolymers

In this paper, we report on the device physics and charge transport characteristics of high-mobility dual-gated polymer thin-film transistors with active semiconductor layers consisting of thiophene flanked DPP with thienylene-vinylene-thienylene (PDPP-TVT) alternating copolymers. Room temperature mobilities in these devices are high and can exceed 2 cm2 V-1 s-1. Steady-state and non-quasi-static measurements have been performed to extract key transport parameters and velocity distributions of charge carriers in this copolymer. Charge transport in this polymer semiconductor can be explained using a Multiple-Trap-and-Release or Monroe-type model. We also compare the activation energy vs. field-effect mobility in a few important polymer semiconductors to gain a better understanding of transport of DPP systems and make appropriate comparisons.

Poly(2,5-bis(2-octyldodecyl)-3,6-di(furan-2-yl)-2,5-dihydro-pyrrolo[3,4-c] pyrrole-1,4-dione-co-thieno[3,2-b]thiophene): A high performance polymer semiconductor for both organic thin film transistors and organic photovoltaics

A new diketopyrrolopyrrole (DPP)-containing donor-acceptor polymer, poly(2,5-bis(2-octyldodecyl)-3,6-di(furan-2-yl)-2,5-dihydro-pyrrolo[3,4-c] pyrrole-1,4-dione-co-thieno[3,2-b]thiophene) (PDBF-co-TT), is synthesized and studied as a semiconductor in organic thin film transistors (OTFTs) and organic photovoltaics (OPVs). High hole mobility of up to 0.53 cm 2 V -1 s -1 in bottom-gate, top-contact OTFT devices is achieved owing to the ordered polymer chain packing and favoured chain orientation, strong intermolecular interactions, as well as uniform film morphology of PDBF-co-TT. The optimum band gap of 1.39 eV and high hole mobility make this polymer a promising donor semiconductor for the solar cell application. When paired with a fullerene acceptor, PC 71BM, the resulting OPV devices show a high power conversion efficiency of up to 4.38% under simulated standard AM1.5 solar illumination.

Water-based nanoparticulate solar cells using a diketopyrrolopyrrole donor polymer

Organic photovoltaic devices with either bulk heterojunction (BHJ) or nanoparticulate (NP) active layers have been prepared from a 1:2 blend of (poly{3,6-dithiophene-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1, 4-dione-alt-naphthalene}) (PDPP-TNT) and the fullerene acceptor, ([6,6]-phenyl C71-butyric acid methyl ester) (PC70BM). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) have been used to investigate the morphology of the active layers of the two approaches. Mild thermal treatment of the NP film is required to promote initial joining of the NPs in order for the devices to function, however the NP structure is retained. Consequently, whereas gross phase segregation of the active layer occurs in the BHJ device spin cast from chloroform, the nanoparticulate approach retains control of the material domain sizes on the length scale of exciton diffusion in the materials. As a result, NP devices are found to generate more than twice the current density of BHJ devices and have a substantially greater overall efficiency. The use of aqueous nanoparticulate dispersions offers a promising approach to control the donor acceptor morphology on the nanoscale with the benefit of environmentally- friendly, solution-based fabrication. © 2014 the Owner Societies.

A comparison of factors influencing perceived risk by French and Australian cyclists and drivers

Differences in the levels of risk perceived by cyclists and car drivers may contribute to the dangers in their interactions. Levels of perceived risk have been shown to vary according to personal and environmental factors and between countries. Cycling rates in France are higher than in Australia, particularly among women. This study investigated whether cultural differences between France and Australia are reflected in perceived risks for experienced adult cyclists and drivers in the two countries. In online surveys, regular cyclists (France 336, Australia 444) and drivers (France 92, Australia 151) were asked to rate the level of risk in six situations: failure to yield; going through a red light; not signalling when turning; swerving; tail-gating; and not checking traffic. The effects of type of interacting vehicle and participant type on perceived risk were similar in France and Australia. However, the influence of responsibility for the risky behaviour differed according to participant type, type of situation and nationality. When the bicycle rider committed the road rule violation, Australian cyclists and drivers gave higher risk ratings than French cyclists and drivers. In both countries, cyclists rated themselves significantly higher than drivers on the perceived control and overconfidence subscales of the perceived skill measure. The French cyclists rated themselves higher than Australian cyclists on these scales, which could be responsible for overall lower perceived risk levels when interacting with a bike. Australian cyclists rated themselves significantly lower than drivers on the incompetence subscale but French cyclists rated themselves higher than drivers. In both countries incompetence scores were positively related to levels of perceived risk. Weekly time was associated with perceived risk in Australia but not in France. Frequency of traffic violations was not associated with perceived risk in either country. In conclusion, levels of perceived risk differed between drivers and cyclists in both countries and were influenced by type of interacting vehicle, experience and perceived skill. However, some differences between the results from the two countries merit further investigation to shed light on potential improvements in safety and cycling participation.