Coexistence of stable spots and fronts in a three-component FitzHugh-Nagumo system

We investigate regions of bistability between different travelling and stationary structures in a planar singularly-perturbed three-component reaction-diffusion system that arises in the context of gas discharge systems. In previous work, we delineated the existence and stabil-ity regions of stationary localized spots in this system. Here, we complement this analysis by establishing the stability regions of planar travelling fronts and stationary stripes. Taken together, these results imply that stable fronts and spots can coexist in three-component systems. Numerical simulations indicate that the stable fronts never move towards stable spots but instead move away from them.

Towards distributed citizen participation : lessons from WikiLeaks and the Queensland floods

This paper examines the rapid and ad hoc development and interactions of participative citizen communities during acute events, using the examples of the 2011 floods in Queensland, Australia, and the global controversy surrounding Wikileaks and its spokesman, Julian Assange. The self-organising community responses to such events which can be observed in these cases bypass or leapfrog, at least temporarily, most organisational or administrative hurdles which may otherwise frustrate the establishment of online communities; they fast-track the processes of community development and structuration. By understanding them as a form of rapid prototyping, e-democracy initiatives can draw important lessons from observing the community activities around such acute events.

Happenings and sensational journalism [O acontecimento e o sensacional no jornalismo]

EM artigo anteriormente publicado (AGUIAR, 2008a), concluímos que as críticas elaboradas por certos autores (SOUSA, 2000; KURTZ, 1993; MARSHALL, 2003; MARCONDES FILHO, 1988), ao classificarem um determinado modo de jornalismo como sensacionalista, parecem querer opor uma imaginária constituição democrática do espaço público e da cultura legítima a uma suposta disfunção narcotizante do entretenimento, que promoveria o conformismo social e reforçaria as normas sociais. O jornalismo sensacionalista, nesse entendimento, veicularia apenas a ampla trivialidade e o excesso de diversão estaria “matando” os ideais iluministas da sociedade moderna, tal como aposta Postman (1986). Entretanto, pode-se ver nestas críticas aquilo que Edgar Morin define, ao estudar cultura de lazer, como a má impressão causada pelo divertimento e pela evasão aos “moralistas dessa confederação helvética do espírito que são as letras e a universidade” (MORIN, 2002).

Participatory content creation and collective intelligence in Rio de Janeiro's favelas

This proposal combines ethnographic techniques and discourse studies to investigate a collective of people engaged with audiovisual productions who collaborate in Curta Favela’s workshops in Rio de Janeiro’s favelas. ‘Favela’ is often translated simply as ‘slum’ or ‘shantytown’, but these terms connote negative characteristics such as shortage, poverty, and deprivation which end up stigmatizing these low income suburbs. Curta Favela (Favela Shorts) is an independent project in which all participants join to use photography and participatory audiovisual production as tools for social change and to raise consciousness. As cameras are not affordable for favela dwellers, Curta Favela’s volunteers teach favela residents how they can use their mobile phones and compact cameras to take pictures and make movies, and afterwards, how they can edit the data using free editing video software programs and publish it on the Internet. To record audio, they use their mp3 or mobile phones. The main aim of this study is to shed light not only on how this project operates, but also to highlight how collective intelligence can be used as a way of fighting against a lack of basic resources.

Key priorities for Australian infection control : summary of findings from the launch of the Centre for Research Excellence in Reducing Healthcare Associated Infections

The launch of the Centre of Research Excellence in Reducing Healthcare Associated Infection (CRE-RHAI) took place in Sydney on Friday 12 October 2012. The mission of the CRE-RHAI is to generate new knowledge about strategies to reduce healthcare associated infections and to provide data on the cost-effectiveness of infection control programs. As well as launching the CRE-RHAI, an important part of this event was a stakeholder Consultation Workshop, which brought together several experts in the Australian infection control community. The aims of this workshop were to establish the research and clinical priorities in Australian infection control, assess the importance of various multi-resistant organisms, and to gather information about decision making in infection control. We present here a summary and discussion of the responses we received.

Mixed convection over a horizontal plate with streamwise non-uniform surface temperature distribution

Numerical investigation on mixed convection of a two-dimensional incompressible laminar flow over a horizontal flat plate with streamwise sinusoidal distribution of surface temperature has been performed for different values of Rayleigh number, Reynolds number and frequency of periodic temperature for constant Prandtl number and amplitude of periodic temperature. Finite element method adapted to rectangular non-uniform mesh elements by a non-linear parametric solution algorithm basis numerical scheme has been employed. The investigating parameters are the Rayleigh number, the Reynolds number and frequency of periodic temperature. The effect of variation of individual investigating parameters on mixed convection flow characteristics has been studied to observe the hydrodynamic and thermal behavior for while keeping the other parameters constant. The fluid considered in this study is air with Prandtl number 0.72. The results are obtained for the Rayleigh number range of 102 to 104, Reynolds number ranging from 1 to 100 and the frequency of periodic temperature from 1 to 5. Isotherms, streamlines, average and local Nusselt numbers are presented to show the effect of the different values of aforementioned investigating parameters on fluid flow and heat transfer.

Natural convection flow in a strong cross magnetic field with radiation

The problem of MHD natural convection boundary layer flow of an electrically conducting and optically dense gray viscous fluid along a heated vertical plate is analyzed in the presence of strong cross magnetic field with radiative heat transfer. In the analysis radiative heat flux is considered by adopting optically thick radiation limit. Attempt is made to obtain the solutions valid for liquid metals by taking Pr≪1. Boundary layer equations are transformed in to a convenient dimensionless form by using stream function formulation (SFF) and primitive variable formulation (PVF). Non-similar equations obtained from SFF are then simulated by implicit finite difference (Keller-box) method whereas parabolic partial differential equations obtained from PVF are integrated numerically by hiring direct finite difference method over the entire range of local Hartmann parameter, $xi$ . Further, asymptotic solutions are also obtained for large and small values of local Hartmann parameter $xi$ . A favorable agreement is found between the results for small, large and all values of $xi$ . Numerical results are also demonstrated graphically by showing the effect of various physical parameters on shear stress, rate of heat transfer, velocity and temperature.

Is providing elective ventilation in the best interests of potential donors?

In this paper, we examine the lawfulness of a proposal to provide elective ventilation to incompetent patients who are potential organ donors. Under the current legal framework, this depends on whether the best interests test could be satisfied. It might be argued that, because the Mental Capacity Act 2005 (UK) (and the common law) makes it clear that the best interests test is not confined to the patient's clinical interests, but extends to include the individual's own values, wishes and beliefs, the proposal will be in the patient's best interests. We reject this claim. We argue that, as things currently stand, the proposal could not lawfully be justified as a blanket proposition by reference to the best interests test. Accordingly, a modification of the law would be necessary to render the proposal lawful. We conclude with a suggestion about how that could be achieved.

Developing capabilities for social inclusion : engaging diversity through inclusive school communities

The effort to make schools more inclusive, together with the pressure to retain students until the end of secondary school, has greatly increased both the number and educational requirements of students enrolling in their local school. Of critical concern, despite years of research and improvements in policy, pedagogy and educational knowledge, is the enduring categorisation and marginalization of students with diverse abilities. Research has shown that it can be difficult for schools to negotiate away from the pressure to categorise or diagnose such students, particularly those with challenging behaviour. In this paper, we highlight instances where some schools have responded to increasing diversity by developing new cultural practices to engage both staff and students; in some cases, decreasing suspension while improving retention, behaviour and performance.

Auspices

Poem about global warming, eco-criticism, the pastoral myth.

Nucleation experiments in a microgravity environment

A simple experimental apparatus is described in which a wide variety of vapor phase nucleation studies of refractory materials could be performed aboard NASA's KC-135 Research Aircraft. The chief advantage of a microgravity environment for these studies is the expected absence of thermally driven convective motions in the gas. The absence of convection leads to much more accurate knowledge of both the temperature distribution in the system and the time evolution of the refractory vapor concentration as a function of distance from the crucible.The evolution of the apparatus will be described as more experience is gained with the microgravity environment. Such experiments will be used to prepare for similar ones carried out aboard either the shuttle or Space Station where considerably longer duration experiments are possible.

A safe system-based approach to selection of clear zones, safety barriers and other roadside treatments

On average, 560 fatal run-off-road crashes occur annually in Australia and 135 in New Zealand. In addition, there are more than 14,000 run-off-road crashes causing injuries each year across both countries. In rural areas, run-off-road casualty crashes constitute 50-60% of all casualty crashes. Their severity is particularly high with more than half of those involved sustaining fatal or serious injuries. This paper reviews the existing approach to roadside hazard risk assessment, selection of clear zones and hazard treatments. It proposes a modified approach to roadside safety evaluation and management. It is a methodology based on statistical modelling of run-off-road casualty crashes, and application of locally developed crash modification factors and severity indices. Clear zones, safety barriers and other roadside design/treatment options are evaluated with a view to minimise fatal and serious injuries – the key Safe System objective. The paper concludes with a practical demonstration of the proposed approach. The paper is based on findings from a four-year Austroads research project into improving roadside safety in the Safe System context.

Characterization and catalytic performance of Fe3Ni8/palygorskite for catalytic cracking of benzene

Catalytic decomposition is a very attractive way to convert tar components into H2, CO and other useful chemicals. The performance of Fe3Ni8/PG (palygorskite, PG) reduced in hydrogen at different temperatures for the catalytic decomposition of benzene has been assessed. Benzene was used as the model biomass tar. The effects of calcination atmosphere, temperatures and benzene concentration on catalytic cracking of benzene were measured. The results of XRD (X-Ray Diffraction), TEM (Transmission Electron Microscope), TPR (Temperature Program Reduction), TPSR (Temperature Program Surface Reduction), TC (Total Carbon), the reactivity component and reaction mechanism over Fe3Ni8/PG for catalytic cracking of benzene are discussed. The results showed particles of awaruite (Fe, Ni) about 2–30 nm were found on the surface of palygorskite by TEM when the calcination temperature was 600 °C. Particles with size smaller than 30 nm were obtained on all prepared Fe3Ni8/PG catalysts as shown by XRD. The nanoparticles proved to be the reactive component for catalytic cracking of benzene and the increase of active particle size caused the decrease in the reactivity of Fe3Ni8/PG. Fe3Ni8/PG annealed in hydrogen at 600 °C was proved to have the best reactivity in experiments (45% hydrogen yield). High concentration benzene (448 g/m3) accelerated the formation of carbon deposition. However, iron oxide decreases carbon deposition and increases the stability of catalyst for catalytic cracking of benzene. The application of Fe3Ni8/PG catalysts was proved a very effective catalyst for the catalytic cracking of benzene.

Transmission system expansion planning considering combined operation of wind farms and energy storage systems

An energy storage system (ESS) can provide ancillary services such as frequency regulation and reserves, as well as smooth the fluctuations of wind power outputs, and hence improve the security and economics of the power system concerned. The combined operation of a wind farm and an ESS has become a widely accepted operating mode. Hence, it appears necessary to consider this operating mode in transmission system expansion planning, and this is an issue to be systematically addressed in this work. Firstly, the relationship between the cost of the NaS based ESS and its discharging cycle life is analyzed. A strategy for the combined operation of a wind farm and an ESS is next presented, so as to have a good compromise between the operating cost of the ESS and the smoothing effect of the fluctuation of wind power outputs. Then, a transmission system expansion planning model is developed with the sum of the transmission investment costs, the investment and operating costs of ESSs and the punishment cost of lost wind energy as the objective function to be minimized. An improved particle swarm optimization algorithm is employed to solve the developed planning model. Finally, the essential features of the developed model and adopted algorithm are demonstrated by 18-bus and 46-bus test systems.

A hydrogen/methane sensor based on niobium tungsten oxide nanorods synthesised by hydrothermal method

An investigation on hydrogen and methane sensing performance of hydrothermally formed niobium tungsten oxide nanorods employed in a Schottky diode structure is presented herein. By implementing tungsten into the surface of the niobium lattice, we create Nb5+ and W5+ oxide states and an abundant number of surface traps, which can collect and hold the adsorbate charge to reinforce a greater bending of the energy bands at the metal/oxide interface. We show experimentally, that extremely large voltage shifts can be achieved by these nanorods under exposure to gas at both room and high temperatures and attribute this to the strong accumulation of the dipolar charges at the interface via the surface traps. Thus, our results demonstrate that niobium tungsten oxide nanorods can be implemented for gas sensing applications, showing ultra-high sensitivities.