Photoelectron spectroscopy of HCCN- and HCNC- reveals the quasilinear triplet carbenes, HCCN and HCNC

Negative ion photoelectron spectroscopy has been used to study the HCCN- and HCNC- ions. The electron affinities (EA) of cyanocarbene have been measured to be EA(HCCN (X) over tilde (3)Sigma(-)=2.003+/-0.014 eV and EA(DCCN (X) over tilde (3)Sigma(-))=2.009+/-0.020 eV. Photodetachment of HCCN- to HCCN (X) over tilde (3)Sigma(-) shows a 0.4 eV long vibrational progression in nu(5), the H-CCN bending mode; the HCCN- photoelectron spectra reveal excitations up to 10 quanta in nu(5). The term energies for the excited singlet state are found to be T-0(HCCN (a) over tilde (1)A('))=0.515+/-0.016 eV and T-0(DCCN (a) over tilde (1)A('))=0.518+/-0.027 eV. For the isocyanocarbene, the two lowest states switch and HCNC has a singlet ground state and an excited triplet state. The electron affinities are EA(HCNC (X) over tilde (1)A('))=1.883+/-0.013 eV and EA((X) over tilde (1)A(') DCNC)=1.877+/-0.010 eV. The term energy for the excited triplet state is T-0(HCNC (a) over tilde (3)A("))=0.050+/-0.028 eV and T-0(DCNC (a) over tilde (3)A("))=0.063+/-0.030 eV. Proton transfer kinetics in a flowing afterglow apparatus were used to re-measure the enthalpy of deprotonation of CH3NC to be Delta(acid)H(298)(CH3NC)=383.6+/-0.6 kcal mol(-1). The acidity/EA thermodynamic cycle was used to deduce D-0(H-CHCN)=104+/-2 kcal mol(-1) [Delta(f)H(0)(HCCN)=110+/-4 kcal mol(-1)] and D-0(H-CHNC)=106+/-4 kcal mol(-1) [Delta(f)H(0)(HCNC)=133+/-5 kcal mol(-1)]. (C) 2002 American Institute of Physics.

Correlates of physical activity behavior in rural youth

The purpose of this study was to identify correlates of physical activity behavior in a sample of rural, predominantly African American youth. Three hundred sixty-one fifth-grade students from two rural counties in South Carolina (69% African American, median age = II years) completed a questionnaire designed to measure beliefs and social influences regarding physical activity, physical activity self-efficacy, perceived physical activity habits of family members and friends, and access to exercise and fitness equipment at home. After school physical activity and television watching were assessed using the Previous Day Physical Activity Recall (PDPAR). Students were classified as physically active according to a moderate physical activity standard: two or more 30-min blocks at an intensity of 3 METs (metabolic equivalents) or greater, and a vigorous physical activity standard: one or more 30-min blocks at an intensity of 6 METs or greater According to the moderate physical activity standard, 34.9% of students were classified as low-active. Multivariate analysis revealed age, gender television watching, and exercise equipment at home to be significant correlates of low activity status. According to the vigorous physical activity standard, 32.1 % of the students were classified as low-active. Multivariate analysis revealed age, gender television watching, and self-efficacy with respect to seeking support for physical activity to be significant correlates of low activity status. In summary, gender and the amount of television watching were found to be the most important correlates of physical activity in rural, predominantly African American youth.

Improving combustion stability in sugar factory boilers

Reliable operation of a sugar factory boiler station is essential for efficient and timely processing of the cane supply. Sugar factory boilers have to contend with changes in fuel quality caused by variations in performance of the extraction station, different cane varieties and associated agronomic factors along with fluctuations in factory steam demand. These variations can affect the stability of combustion in boiler furnaces leading to reductions in boiler steam output and large furnace pressure fluctuations that can cause serious damage. This paper investigates the causes of unstable combustion, discusses aspects of boiler design that make a boiler more susceptible to unstable combustion and uses modelling to evaluate different options for improving combustion stability.

The transformation of bureaucracy? Structural change in the Commonwealth public service 1983-93

Commentators have predicted bureaucratic organisations would undergo substantial change as a result of social and economic pressures. We ask whether reforms to the Australian public service over the 1983–93 period exemplify this process. We use the methods of organisational analysis to characterise the direction of change, basing our assessment on the standard structural variables of complexity, formalisation and centralisation, together with a cultural variable. We find evidence that, overall, departments of state in the APS were becoming less bureaucratic in their structure, culture and internal function in the 1983–93 period. However, the effect was not uniform across departments, or unambiguous — formalisation, for example, increased in some respects and decreased in others. Centralisation increased overall, despite devolution of some decision-making.

Porous versus porthole fuel injection in a radical farming scramjet: A numerical analysis

Numerically computed engine performance of a nominally two-dimensional radical farming scramjet with porous (permeable C/C ceramic) and porthole fuel injection is presented. Inflow conditions with Mach number, stagnation pressure, and enthalpy of 6.44, 40.2MPa, and 4.31 MJ/kg respectively, and fuel/air equivalence ratio of 0.44 were maintained, along with engine geometry. Hydrogen fuel was injected at an axial location of 92.33mm downstream of the leading edge for each investigated injection method. Results from this study show that porous fuel injection results in enhanced mixing and combustion compared to porthole fuel injection. This is particularly evident within the first half of the combustion chamber where porous fuel injection resulted in mixing and combustion efficiencies of 76% and 63% respectively. At the same location, porthole fuel injection resulted in efficiencies respectively of 58% and 46%. Key mechanisms contributing to the observed improved performance were the formation of an attached oblique fuel injection shock and associated stronger shock-expansion train ingested by the engine, enhanced spreading of the fuel in all directions and a more rapidly growing mixing layer.

Synthesis of imines from amines in aliphatic alcohols on Pd/ZrO2 catalyst under ambient conditions

Synthesis of imines from amines and aliphatic alcohols (C1–C6) in the presence of base on supported palladium nanoparticles has been achieved for the first time. The catalytic system shows high activity and selectivity in open air at room temperature. As an example of the isostructural Ln3Sb3Co2O14 (Ln: La, Pr, Nd, Sm—Ho) series with an ordered pyrochlore structure, the La variant is prepared by a citrate complex method employing stoichiometric amounts of La(NO3)3, Co(NO3)2, and Sb tartrate together with citric acid with a metal/citrate molar ratio of 1:2

Inter-cycle variability of ignition delay in an ethanol fumigated common rail diesel engine

An experimental study has been performed to investigate the ignition delay of a modern heavy-duty common-rail diesel engine run with fumigated ethanol substitutions up to 40% on an energy basis. The ignition delay was determined through the use of statistical modelling in a Bayesian framework this framework allows for the accurate determination of the start of combustion from single consecutive cycles and does not require any differentiation of the in-cylinder pressure signal. At full load the ignition delay has been shown to decrease with increasing ethanol substitutions and evidence of combustion with high ethanol substitutions prior to diesel injection have also been shown experimentally and by modelling. Whereas, at half load increasing ethanol substitutions have increased the ignition delay. A threshold absolute air to fuel ratio (mole basis) of above ~110 for consistent operation has been determined from the inter-cycle variability of the ignition delay, a result that agrees well with previous research of other in-cylinder parameters and further highlights the correlation between the air to fuel ratio and inter-cycle variability. Numerical modelling to investigate the sensitivity of ethanol combustion has also been performed. It has been shown that ethanol combustion is sensitive to the initial air temperature around the feasible operating conditions of the engine. Moreover, a negative temperature coefficient region of approximately 900{1050 K (the approximate temperature at fuel injection) has been shown with for n-heptane and n-heptane/ethanol blends in the numerical modelling. A consequence of this is that the dominate effect influencing the ignition delay under increasing ethanol substitutions may rather be from an increase in chemical reactions and not from in-cylinder temperature. Further investigation revealed that the chemical reactions at low ethanol substitutions are different compared to the high (> 20%) ethanol substitutions.

A homogeneous surface-enhanced Raman scattering platform for ultra-trace detection of trinitrotoluene in the environment

A facile and sensitive surface-enhanced Raman scattering substrate was prepared by controlled potentiostatic deposition of a closely packed single layer of gold nanostructures (AuNS) over a flat gold (pAu) platform. The nanometer scale inter-particle distance between the particles resulted in high population of ‘hot spots’ which enormously enhanced the scattered Raman photons. A renewed methodology was followed to precisely quantify the SERS substrate enhancement factor (SSEF) and it was estimated to be (2.2 ± 0.17) × 105. The reproducibility of the SERS signal acquired by the developed substrate was tested by establishing the relative standard deviation (RSD) of 150 repeated measurements from various locations on the substrate surface. A low RSD of 4.37 confirmed the homogeneity of the developed substrate. The sensitivity of pAu/AuNS was proven by determining 100 fM 2,4,6-trinitrotoluene (TNT) comfortably. As a proof of concept on the potential of the new pAu/AuNS substrate in field analysis, TNT in soil and water matrices was selectively detected after forming a Meisenheimer complex with cysteamine.

Attributions of responsibility, blame and justifiability to a perpetrator and victim in an acquaintance rape scenario: The influence of Marijuana intoxication

Marijuana is a commonly used illicit drug by young adults and has been implicated in about one third of sexual assaults. However, the influence of Marijuana intoxication on rape attributions has not been previously investigated. This study examined the effects of perpetrator and victim Marijuana intoxication and participant sex on rape attributions. Young adults (N = 285) read an acquaintance rape scenario where Marijuana intoxication was manipulated and completed measures of perpetrator (responsibility, blame and justifiability) and victim attributions (responsibility and blame). The results revealed that an intoxicated, compared to sober, perpetrator was attributed less responsibility for his sexual aggression. When the victim was intoxicated, compared to sober, the perpetrator and victim were attributed less and more blame for the assault, respectively. These findings demonstrate that, irrespective of perceiver sex, Marijuana intoxication, like alcohol intoxication, results in an attributional double standard in favour of the perpetrator.

Quantification of stability in an agility drill using linear and nonlinear measures of variability

This study implemented linear and nonlinear methods of measuring variability to determine differences in stability of two groups of skilled (n = 10) and unskilled (n = 10) participants performing 3m forward/backward shuttle agility drill. We also determined whether stability measures differed between the forward and backward segments of the drill. Finally, we sought to investigate whether local dynamic stability, measured using largest finite-time Lyapunov exponents, changed from distal to proximal lower extremity segments. Three-dimensional coordinates of five lower extremity markers data were recorded. Results revealed that the Lyapunov exponents were lower (P < 0.05) for skilled participants at all joint markers indicative of higher levels of local dynamic stability. Additionally, stability of motion did not differ between forward and backward segments of the drill (P > 0.05), signifying that almost the same control strategy was used in forward and backward directions by all participants, regardless of skill level. Furthermore, local dynamic stability increased from distal to proximal joints (P < 0.05) indicating that stability of proximal segments are prioritized by the neuromuscular control system. Finally, skilled participants displayed greater foot placement standard deviation values (P < 0.05), indicative of adaptation to task constraints. The results of this study provide new methods for sport scientists, coaches to characterize stability in agility drill performance.

Visible light enhanced oxidant free dehydrogenation of aromatic alcohols using Au-Pd alloy nanoparticle catalysts

We find that visible light irradiation of gold–palladium alloy nanoparticles supported on photocatalytically inert ZrO2 significantly enhances their catalytic activity for oxidant-free dehydrogenation of aromatic alcohols to the corresponding aldehydes at ambient temperatures. Dehydrogenation is also the dominant process in the selective oxidation of the alcohols to the corresponding aldehydes with molecular oxygen. The alloy nanoparticles strongly absorb light and exhibit superior catalytic and photocatalytic activity when compared to either pure palladium or gold nanoparticles. Analysis with a free electron gas model for the bulk alloy structure reveals that the alloying increases the surface charge heterogeneity on the alloy particle surface, which enhances the interaction between the alcohol molecules and the metal NPs. The increased surface charge heterogeneity of the alloy particles is confirmed with density function theory applied to small alloy clusters. Optimal catalytic activity was observed with a Au : Pd molar ratio of 1 : 186, which is in good agreement with the theoretical analysis. The rate-determining step of the dehydrogenation is hydrogen abstraction. The conduction electrons of the nanoparticles are photo-excited by the incident light giving them the necessary energy to be injected into the adsorbed alcohol molecules, promoting the hydrogen abstraction. The strong chemical adsorption of alcohol molecules facilitates this electron transfer. The results show that the alloy nanoparticles efficiently couple thermal and photonic energy sources to drive the dehydrogenation. These findings provide useful insight into the design of catalysts that utilize light for various organic syntheses at ambient temperatures.

Specific rolling circle amplification of low-copy human polyomaviruses BKV, HPyV6, HPyV7, TSPyV, and STLPyV

Eleven new human polyomaviruses have been recently discovered, yet for most of these viruses, little is known of their biology and clinical impact. Rolling circle amplification (RCA) is an ideal method for the amplification of the circular polyomavirus genome due to its high fidelity amplification of circular DNA. In this study, a modified RCA method was developed to selectively amplify a range of polyomavirus genomes. Initial evaluation showed a multiplexed temperature-graded reaction profile gave the best yield and sensitivity in amplifying BK polyomavirus in a background of human DNA, with up to 1 × 10(8)-fold increases in viral genomes from as little as 10 genome copies per reaction. Furthermore, the method proved to be more sensitive and provided a 200-fold greater yield than that of random hexamers based standard RCA. Application of the method to other novel human polyomaviruses showed successful amplification of TSPyV, HPyV6, HPyV7, and STLPyV from low-viral load positive clinical samples, with viral genome enrichment ranging from 1 × 10(8) up to 1 × 10(10). This directed RCA method can be applied to selectively amplify other low-copy polyomaviral genomes from a background of competing non-specific DNA, and is a useful tool in further research into the rapidly expanding Polyomaviridae family.

Pulse-echo ultrasound transit time spectroscopy: A comparison of experimental measurements and simulation prediction

Considering ultrasound propagation through complex composite media as an array of parallel sonic rays, a comparison of computer simulated prediction with experimental data has previously been reported for transmission mode (where one transducer serves as transmitter, the other as receiver) in a series of ten acrylic step-wedge samples, immersed in water, exhibiting varying degrees of transit time inhomogeneity. In this study, the same samples were used but in pulse-echo mode, where the same ultrasound transducer served as both transmitter and receiver, detecting both ‘primary’ (internal sample interface) and ‘secondary’ (external sample interface) echoes. A transit time spectrum (TTS) was derived, describing the proportion of sonic rays with a particular transit time. A computer simulation was performed to predict the transit time and amplitude of various echoes created, and compared with experimental data. Applying an amplitude-tolerance analysis, 91.7±3.7% of the simulated data was within ±1 standard deviation (STD) of the experimentally measured amplitude-time data. Correlation of predicted and experimental transit time spectra provided coefficients of determination (R2) ranging from 100.0% to 96.8% for the various samples tested. The results acquired from this study provide good evidence for the concept of parallel sonic rays. Further, deconvolution of experimental input and output signals has been shown to provide an effective method to identify echoes otherwise lost due to phase cancellation. Potential applications of pulse-echo ultrasound transit time spectroscopy (PE-UTTS) include improvement of ultrasound image fidelity by improving spatial resolution and reducing phase interference artefacts.

Synthesis of mesoporous TiO2/SiO2 hybrid films as an efficient photocatalyst by polymeric micelle assembly

Thermally stable mesoporous TiO2/SiO2 hybrid films with pore size of 50 nm have been synthesized by adopting the polymeric micelle-assembly method. A triblock copolymer, poly(styrene-b-2-vinyl pyridine-b-ethylene oxide), which serves as a template for the mesopores, was utilized to form polymeric micelles. The effective interaction of titanium tetraisopropoxide (TTIP) and tetraethyl orthosilicate (TEOS) with the polymeric micelles enabled us to fabricate stable mesoporous films. By changing the molar ratio of TEOS and TTIP, several mesoporous TiO2/SiO2 hybrid films with different compositions can be synthesized. The presence of amorphous SiO2 phase effectively retards the growth of anatase TiO2 crystal in the pore walls and retains the original mesoporous structure, even at higher temperature (650 °C). These TiO2/SiO2 hybrid films are of very high quality, without any cracks or voids. The addition of SiO2 phase to mesoporous TiO2 films not only adsorbs more organic dyes, but also significantly enhances the photocatalytic activity compared to mesoporous pure TiO2 film without SiO2 phase.

The prevalence and correlates of childhood trauma in patients with early psychosis

Objective: To describe the prevalence and demographic, clinical and functional correlates of childhood trauma in patients attending early psychosis clinics. Method: Participants were recruited from outpatients attending four early psychosis services. Exposure to childhood trauma was assessed using the Childhood Trauma Questionnaire (CTQ). Psychopathology was measured using the Positive and Negative Syndrome Scale and the Depression, Anxiety and Stress Scale. Social and vocational functioning and substance use were also assessed. Results: Over three-quarters of the 100 patients reported exposure to any childhood trauma. Emotional, physical and sexual abuse were reported by 54%, 23% and 28% of patients, respectively, while 49% and 42% of patients reported emotional and physical neglect, respectively. Female participants were significantly more likely to be exposed to emotional and sexual abuse. Exposure to childhood trauma was correlated with positive psychotic symptoms and higher levels of depressive, anxiety and stress symptoms; however, it had no impact on social or vocational functioning or recent substance use. Conclusion: Exposure to childhood trauma was common in patients with early psychosis, and associated with increased symptomatology. Existing recommendations that standard clinical assessment of patients with early psychosis should include inquiry into exposure to childhood trauma are supported.