Rates of student-reported antisocial behavior, school suspensions, and arrests in Victoria, Australia and Washington State, United States

Background: Few methodologically rigorous international comparisons of student-reported antisocial behavior have been conducted. This paper examines whether there are differences in the frequency of both antisocial behavior and societal responses to antisocial behavior in Victoria, Australia and Washington State, United States. These 2 states were chosen due to their similarities on sociodemographic characteristics and their differences in policy frameworks around problem behavior including antisocial behavior and substance use.

Methods: State representative samples of students (N = 5769) in school grades 5, 7, and 9 in Victoria and Washington State completed a modified version of the Communities That Care self-report survey of behavior and societal responses to behavior. Chi-square analyses compared frequencies of antisocial behavior, school suspensions, and police arrests in the 2 states. Multivariate logistic regression analyses were conducted for each outcome measure to examine the effect of state, controlling for sample design, clustering of students within schools, age, socioeconomic status, and urbanicity.

Results: Few state differences in student-reported antisocial behavior were found, although frequencies varied across behavior type and grade level. Differences in societal responses were observed across grade levels with grade 5 Washington students reporting higher rates of school suspension. Older Washington students reported more arrests.

Conclusions: Rates of student antisocial behavior appear similar in these 2 states in Australia and the United States. However, youth in the United States relative to Australia may experience greater societal consequences for problem behavior. Further research is required to examine the impact of these consequences on subsequent behavior.

The effect of school suspensions and arrests on subsequent adolescent antisocial behavior in Australia and the United States

Purpose: To examine the effect of school suspensions and arrests (i.e., being taken into police custody) on subsequent adolescent antisocial behavior such as violence and crime, after controlling for established risk and protective factors in Victoria, Australia and Washington State, United States (U.S.). Methods: This article reports on analyses of two points of data collected 1 year apart within a cross-national longitudinal study of the development of antisocial behavior, substance use, and related behaviors in approximately 4000 students aged 12 to 16 years in Victoria, Australia and Washington State, U.S. Students completed a modified version of the Communities That Care self-report survey of behavior, as well as risk and protective factors across five domains (individual, family, peer, school, and community). Multivariate logistic regression analyses investigate the effect of school suspensions and arrests on subsequent antisocial behavior, holding constant individual, family, peer, school, and community level influences such as being female, student belief in the moral order, emotional control, and attachment to mother. Results: At the first assessment, school suspensions and arrests were more commonly reported in Washington, and school suspensions significantly increased the likelihood of antisocial behavior 12 months later, after holding constant established risk and protective factors (adjusted odds ratio [OR] 1.5, 95% confidence interval [CI] 1.1–2.1, _p < .05). Predictors of antisocial behavior spanned risk and protective factors across five individual and ecological areas of risk. Risk factors in this study were pre-existing antisocial behavior (OR 3.6, CI 2.7–4.7, _p < .001), association with antisocial peers (OR 1.8, CI 1.4–2.4, _p < .001), academic failure (OR 1.3, CI 1.1–1.5, _p < .01), and perceived availability of drugs in the community (OR 1.3, CI 1.1–1.5, _p < .001). Protective factors included being female (OR 0.7, CI 0.5–0.9, _p < .01), student belief in the moral order (OR 0.8, CI 0.6–1.0, p < .05), student emotional control (OR 0.7, CI 0.6–0.8, _p < .001), and attachment to mother (OR 0.8, CI 0.7–1.0, _p < .05). Conclusions:  School suspensions may increase the likelihood of future antisocial behavior. Further research is required to both replicate this finding and establish the mechanisms by which school suspensions exert their effects.

Direct electro-deposition of graphene from aqueous suspensions

We describe the direct electro-chemical reduction of graphene oxide to graphene from aqueous suspension by applying reduction voltages exceeding -1.0 to -1.2 V. The conductivity of the deposition medium is of crucial importance and only values between 4-25 mS cm^-1 result in deposition. Above 25 mS cm^-1 the suspension de-stabilises while conductivities below 4 mS cm_^-1 do not show a measurable deposition rate. Furthermore, we show that deposition can be carried out over a wide pH region ranging from 1.5 to 12.5. The electro-deposition process is characterised in terms of electro-chemical methods including cyclic voltammetry, quartz crystal microbalance, impedance spectroscopy, constant amperometry and potentiometric titrations, while the deposits are analysed via Raman spectroscopy, infra-red spectroscopy, X-ray photoelectron spectroscopy and X-ray diffractometry. The determined oxygen contents are similar to those of chemically reduced graphene oxide, and the conductivity of the deposits was found to be ~20 S cm ^-1.

Electrophoretic deposition of YSZ thin-film electrolyte for SOFCs utilizing electrostatic-steric stabilized suspensions obtained via high energy ball milling

This manuscript describes a facile alternative route to make thin-film yttria-stabilized zirconia (YSZ) electrolyte by liquid-phase assisted electrophoretic deposition utilizing electrostatic-steric stabilized YSZ suspension followed by sintering. Very fine YSZ particles in ball-milled suspension facilitate their sustained dispersion through electrostatic mechanism as evidenced by their higher zeta potentials. Binder addition into the ball-milled suspension is also demonstrated to contribute complementary steric hindrance effects on suspension stability. As the consequence, the film quality and sinterability improve in the sequence of film made from non ball-milled suspension, film made from ball-milled suspension and film made from ball-milled suspension with binder addition. The specific deposition mechanisms pertaining to each suspension are also postulated and discussed below. A very thin dense electrolyte layer of ∼10 μm can be achieved via electrophoretic deposition route utilizing ball-milled suspension and binder addition. This in turn, makes the electrolyte resistance a more negligible part of the overall cell resistance. Further on, we also tested the performance of SOFC utilizing as-formed 10 μm YSZ electrolyte i.e. YSZ-NiO|YSZ|LSM (La0.8Sr0.2MnO3-δ), whereby a maximum power density of ∼850 mW cm−2 at 850 °C was demonstrated.

Derivation of turbulent energy of fiber suspensions

The energy equation for turbulent flow of fiber suspensions was derived in terms of second order correlation tensors. Fiber motion of turbulent energy including the correlation between pressure fluctuations and velocity fluctuations was discussed at two points of flow field, at which the correlation tensors were the functions of space coordinates, distance between two points, and time.

Modifiable determinants of youth violence in Australia and the United States : a longitudinal study

Youth violence is a global problem. Few studies have examined whrther the prevalence or predictors of youth violence are similar in comparable Western countries like Australia and the United States (US). In the current article, analyses are conducted using two waves of data collected as part of a longitudinal study of adolescent development in approximately 4,000 students aged 12 to 16 years in Victoria, Australia and Washington State, US. Students completed a self-report survey of problem behaviours including violent behaviour, as well as risk and protective factors across five domains (individual, family, peer, school, community). Compared to Washington State, rates of attacking or beating another over the past 12 months were lower in Victoria for females in the first survey and higher for Victorian males in the follow-up survey. Preliminary analyses did not show state-specific predictors of violent behaviour. In the final multivariate analyses of the combined Washington State and Victorian samples, protective factors were being female and student emotion control. Risk factors were prior violent behaviour, family conflict, association with violent peers, community disorganisation, community norms favourable to drug use, school suspensions and arrests. Given the similarity of influential factors in North America and Australia, application of US early intervention and prevention programs may be warranted, with some tailoring to the Australian context.

Flux-assisted self-assembly of monodisperse colloids

We have developed a novel method to grow ordered layers of monodisperse colloids on a flat substrate. The evaporation of the colloidal suspension in the presence of the inclined substrate is strengthened by an external gas flux directed on the meniscus. The meniscus oscillations caused by the gas flux have an evident effect on the ordering of the spheres on the substrate. Thick films (more than 150 layers in a single-step deposition) of large area single crystals (1 cm2) can be obtained in a very short time (~1 cm/h maximum growth rate) and from very diluted suspensions (up to 0.022% volume fraction).

UV-shielding ceramic nanoparticles synthesised by mechanochemcial processing

ZnO, TiO₂ and CeO₂ are known as UV-shielding ceramic materials that have advantages over organic UV absorbers for their photo-stability and non-hazardous nature to human bodies. However, they normally cause low transparency in the visible-light range due to light scattering by large particles, which is undesirable for many transparent UV-blocking applications in cosmetic and plastic industries. Light-scattering efficiency of particles can be drastically reduced by decreasing the particle sizes down below 100 nm. This paper reviews recent investigation on the synthesis of ZnO and CeO₂ nanoparticles by mechanochemical processing. The resulting particles had a significantly low degree of agglomeration, having mean particle sizes of ~ 25 nm and ~ 10 nm, respectively. The aqueous suspensions of the nanoparticles showed strong absorption in the UV-light range and high transmittance in the visible-light range. Mechanochemical processing offers the possibility of industrial-scale production of transparent UV-shielding ceramic particles for many applications.

Effects of backwashing on PVDF membrane fouling by organic foulants

Membrane is usually subject to fouling by various organic foulants, such as yeast, protein and sodium alginate during filtration. Backwashing is a common practice to reduce membrane fouling. It is essential to evaluate the effects of backwashing on fouling in order to optimize operational parameters. In this experiment, poly(vinylidene fluoride) (PVDF) membranes were used to filter organic foulants from suspensions in a dead-end stirred cell. Three types of organic foulants including yeast, protein and sodium alginate which were stained with fluorescent dyes before filtration were used with different combinations in the experiments. After filtration, the PVDF membrane was backwashed.

Consequently, a stack of images, instrumental data and sample data were captured from the fouling layers on the PVDF membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software LAS AF. Then, the quality of the images was enhanced for better visualization and a set of quantitative fouling data were derived by using the software code developed by the project team at Deakin University.

This collection contains raw image data of poly(vinylidene fluoride) (PVDF) membrane’s fouling layer when three types of organic foulants present, which are captured by confocal laser scanning microscopy (CLSM) and its software, and the instrumental and sample metadata, the processed image data and the geometrical structure properties of the fouling layer. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed.

This data collection would be useful to evaluate the backwashing efficiency of PVDF membrane in order to optimize frequency and operational conditions of backwashing by membrane materials researchers and water researchers.

Influence of particle concentration on initial collection efficiency and surface coverage in porous media filtration

Four sizes (0.095, 0.53, 1.0 and 2.01 μm) of polystyrene latex particles were used to prepare monodispersed suspensions at three different ionic strengths (10−3, 10−2.5 and 10−2M KCl). Filtration experiments were conducted using those suspensions in a filter column with glass beads as porous medium. The filter bed depth and the filtration velocity were kept at 5 cm and 1 m/h, respectively. When suspensions with equal mass concentrations (0.2 mg/L) or equal surface area concentrations (0.12 cm2/mL) were filtered through the system, the largest particles exhibited higher initial single collector efficiency, η. The difference between the η of largest particles and the smaller particles was prominent for suspensions with equal surface area concentrations at higher ionic strengths. The collision efficiency, α of those particles exhibits higher values at higher ionic strengths. Both at equal mass concentration and equal surface area concentration, α is only slightly dependent on particle sizes when compared to its dependence on ionic strength. Further, it was found that the specific surface coverage was similar for 0.095 μm, 0.53 μm and 1.0 μm particles during the transient stage of filtration at any ionic strength when the surface area concentrations of those suspension were equal.

Surface coverage of filter medium in deep bed filtration : mathematical modelling and experiments

This paper highlights the importance of surface coverage in modeling the removal of particles in deep bed filtration. A model that considers the saturation of sites on which particle deposition occurs is used. Experimental results obtained with monodispersed suspensions of 0.46 and 0.816 μm latex particles at different influent concentrations and ionic strengths were used to calculate the fraction of filter grain surface (β1) on which actual particle deposition occurs. This will be useful in evaluating the filter performance in terms of the utilization of available surface area of the filter medium. Further, the level of dendrite formation of particles on filter grains during filtration is expressed in terms of β1 and the specific surface coverage, θT (the fraction of a filter grain surface that is covered by particles at time T, assuming that the filter grain is covered by a monolayer of particles). This can be used to compare the contribution of deposited particles in the removal efficiency of deep bed filtration for suspensions with different physical and chemical characteristics.

Hydrophobic attraction may contribute to aqueous flocculation of clays

SEM observations of low solid content vitrified clay suspensions reveal that clay platelets build porous three-dimensional networks with platelets contacting each other mostly by their edges. To explain this behaviour, which must require long range edge-to-edge (EE) attractive forces, a hydrophobic-like interaction has been proposed. This interaction may be induced by the presence of nano-bubbles existing on the edges of clay crystals which may cause clay particles to flocculate. The following indirect evidence for such hydrophobic behaviour is presented. First, a clay platelet is shown attached to an oil drop by its edge; second, clay flocs were attracted by a vertically placed Teflon strip but not to the hydrophilic mica basal surface; third, a much thicker porous sediment occurred in CO2-saturated water solution compared with vacuum degassed water.

Tuneable optical waveguide based on dielectrophoresis and microfluidics

In this work, an array of dielectrophoretic curved microelectrodes patterned in a microfluidic channel and integrated with a multimode rib polymeric waveguide is demonstrated. The microfluidic channel is infiltrated with suspended silica (SiO2) and tungsten trioxide (WO3) nanoparticles. The optofluidic system is found to be sensitive and responds not only to the infiltration of nanoparticle suspensions in the microfluidic channel, but also to the magnitude and frequencies of dielectrophoretic forces applied on the nanoparticles. The nanoparticles can be uniformly concentrated or repelled from the region between the curved microelectrode tips forming either a dense stream of flowing nanoparticles or a region void of nanoparticles in the evanescent sensitive region of the polymeric waveguide. The concentration and repulsion of nanoparticles from this region creates a refractive index gradient in the upper cladding of the polymeric waveguide. These conditions made it possible for light to either remain guided or be scattered as a function of dielectrophoretic settings applied on the nanoparticles. The results demonstrate that we successfully developed a novel tuneable polymeric waveguide based on dielectrophoretic assembly of nanoparticles suspended in fluids.

The impact of school suspension on student tobacco use : a longitudinal study in Victoria, Australia, and Washington State, United States

Context: School suspension may have unintended consequences in contributing to problem behaviors, including dropping out from school, substance use, and antisocial behavior. Tobacco use is an early-onset problem behavior, but prospective studies of the effects of suspension on tobacco use are lacking.

Method: Longitudinal school-based survey of students drawn as a two-stage cluster sample, administered in 2002 and 2003, in Washington State, United States, and Victoria, Australia. The study uses statewide representative samples of students in Grades 7 and 9 (N = 3,599). Results: Rates of tobacco use were higher for Victorian than Washington State students. School suspension remained a predictor of current tobacco use at 12-month follow-up, after controlling for established risk factors including prior tobacco and other drug use for Grade 7 but not Grade 9 students.

Conclusions: School suspension is associated with early adolescent tobacco use, itself an established predictor of adverse outcomes in young people. Findings suggest the need to explore process mechanisms and alternatives to school suspensions as a response to challenging student behavior in early adolescence.

Predictors and responses to the growth in physical violence during adolescence : a comparison of students in Washington State and Victoria, Australia

This study investigates patterns in violence over 3 time points in early to midadolescence in 2 statewide representative samples of youth, one in Washington State, USA, and the other in Victoria, Australia. Comparable data collection methods in both states were used to cross-nationally compare patterns of violence, risk factors, and responses to violence (school suspensions and arrests) in 2 policy contexts. Risk factors include early use of alcohol, binge drinking, involvement with antisocial peers, family conflict, poor family management, sensation seeking, and bully victimization. These are modeled as correlates of initial violence and predictors of change in violence over a 3-year period, from ages 12–15, for participating youth. Results suggest that patterns and predictors of violence are mostly similar in the 2 states. Initial levels of violence (age 13) and change over time in violence were associated in both states with more youth school suspensions and more police arrests in Grade 9. Some cross-national differences were also shown. For example, correlations of violence with gender and violence with binge drinking were stronger in Victoria, whereas correlations of violence with early use of alcohol and with antisocial peer involvement were stronger in Washington State. Antisocial peer involvement and family conflict were significant predictors of a gradual increase in violence from Grades 7–9 for youth in Victoria only. Implications are discussed with attention to prevention and intervention efforts.