Strategy use of children with Down syndrome in a delay of gratification situation

Background: The capacity to delay gratification has been shown to be a very important developmental task for children who are developing typically. There is evidence that children with Down syndrome have more difficulty with a delay of gratification task than typically developing children of the same mental age. This study focused on the strategies children with Down syndrome use while in a delay of gratification situation to ascertain if these contribute to the differences in delay times from those of typically developing children. Method: Thirty-two children with Down syndrome (15 females) and 50 typically developing children participated in the study. Children with Down syndrome had a mental age, as measured by the Stanford-Binet IV, between 36 and 66 months (M = 45.66). The typically developing children had a mean chronological age of 45.76 months. Children participated in a delay of gratification task where they were offered two or one small treats and asked which they preferred. They were then told that they could have the two treats if they waited for the researcher to return (an undisclosed time of 15 min). If they did not want to wait any longer they could call the researcher back but then they could have only one treat. Twenty-two of the children with Down syndrome and 43 of the typically developing children demonstrated understanding of the task and their data are included here. Sessions were videotaped for later analysis. Results: There were significant differences in the mean waiting times of the two groups. The mean of the waiting times for children with Down syndrome was 181.32 s (SD = 347.62) and was 440.21 s (SD = 377.59) for the typically developing children. Eighteen percent of the group with Down syndrome waited for the researcher to return in comparison to 35% of the typically developing group. Sixty-four percent of children with Down syndrome called the researcher back and the remainder (18%) violated. In the typically developing group 37% called the researcher back and 28% violated. The mean waiting time for the group of children with Down syndrome who called the researcher back was 24 s. Examination of strategy use in this group was therefore very limited. There appeared to be quite similar strategy use across the groups who waited the full 15 min. Conclusions: These results confirm the difficulty children with Down syndrome have in delaying gratification. Teaching strategies for waiting, using information drawn from the behaviours of children who are developing typically may be a useful undertaking. Examination of other contributors to delay ability (e.g., language skills) is also likely to be helpful in understanding the difficulties demonstrated in delaying gratification.

Novel methods and the maximum likelihood estimation technique for estimating traffic critical gap

Most unsignalised intersection capacity calculation procedures are based on gap acceptance models. Accuracy of critical gap estimation affects accuracy of capacity and delay estimation. Several methods have been published to estimate drivers’ sample mean critical gap, the Maximum Likelihood Estimation (MLE) technique regarded as the most accurate. This study assesses three novel methods; Average Central Gap (ACG) method, Strength Weighted Central Gap method (SWCG), and Mode Central Gap method (MCG), against MLE for their fidelity in rendering true sample mean critical gaps. A Monte Carlo event based simulation model was used to draw the maximum rejected gap and accepted gap for each of a sample of 300 drivers across 32 simulation runs. Simulation mean critical gap is varied between 3s and 8s, while offered gap rate is varied between 0.05veh/s and 0.55veh/s. This study affirms that MLE provides a close to perfect fit to simulation mean critical gaps across a broad range of conditions. The MCG method also provides an almost perfect fit and has superior computational simplicity and efficiency to the MLE. The SWCG method performs robustly under high flows; however, poorly under low to moderate flows. Further research is recommended using field traffic data, under a variety of minor stream and major stream flow conditions for a variety of minor stream movement types, to compare critical gap estimates using MLE against MCG. Should the MCG method prove as robust as MLE, serious consideration should be given to its adoption to estimate critical gap parameters in guidelines.

Young people whose parents are separated or divorced: A case for researching their experiences at the intersection of home and school

Background: Young people whose parents are separated or divorced form a significant and increasing proportion of young people who attend school. To date, empirical research with young people whose parents are separated or divorced has tended to focus on either their household context, or their school context, rather than on both contexts together. This paper redresses this singular focus by examining the intersection of the experiences of young people at both home and school. Purpose: The paper seeks to map the empirical evidence of young people's home and school experiences as they move between households and schools. Sources of evidence: The paper provides a narrative review of the literature from the 1990s to the present, locating Australian research within an international context. The review is framed by four main questions. What is the impact upon young people of the family transitions that occur when parents separate or divorce? What is the everyday impact upon young people of moving between one household and another? What does the research reveal regarding educational, social and emotional outcomes for this group? What does the research reveal regarding their school experiences? Main argument: The review reveals a paucity of Australian research at the intersection of home and school. It shows that, while young people from these contexts form a growing proportion of the school population, there is little empirical evidence of what is actually occurring in their everyday lives. The review reveals the importance of researching from the perspectives of the young people themselves. Conclusions: Evidence provided in the paper shows that many young people whose parents separate or divorce are affected socially, emotionally and educationally. Such evidence points to the need for research into the everyday experiences of the young people at school, in order to identify, from their perspective, how schools can better cater for these young people and their families.

Establishing initial trust in autonomous delay tolerant networks without centralised PKI

A Delay Tolerant Network (DTN) is one where nodes can be highly mobile, with long message delay times forming dynamic and fragmented networks. Traditional centralised network security is difficult to implement in such a network, therefore distributed security solutions are more desirable in DTN implementations. Establishing effective trust in distributed systems with no centralised Public Key Infrastructure (PKI) such as the Pretty Good Privacy (PGP) scheme usually requires human intervention. Our aim is to build and compare different de- centralised trust systems for implementation in autonomous DTN systems. In this paper, we utilise a key distribution model based on the Web of Trust principle, and employ a simple leverage of common friends trust system to establish initial trust in autonomous DTN’s. We compare this system with two other methods of autonomously establishing initial trust by introducing a malicious node and measuring the distribution of malicious and fake keys. Our results show that the new trust system not only mitigates the distribution of fake malicious keys by 40% at the end of the simulation, but it also improved key distribution between nodes. This paper contributes a comparison of three de-centralised trust systems that can be employed in autonomous DTN systems.

Information practices of teen content creators : the intersection of action and experiences a grounded theory study

What are the information practices of teen content creators? In the United States over two thirds of teens have participated in creating and sharing content in online communities that are developed for the purpose of allowing users to be producers of content. This study investigates how teens participating in digital participatory communities find and use information as well as how they experience the information. From this investigation emerged a model of their information practices while creating and sharing content such as film-making, visual art work, story telling, music, programming, and web site design in digital participatory communities. The research uses grounded theory methodology in a social constructionist framework to investigate the research problem: what are the information practices of teen content creators? Data was gathered through semi-structured interviews and observation of teen’s digital communities. Analysis occurred concurrently with data collection, and the principle of constant comparison was applied in analysis. As findings were constructed from the data, additional data was collected until a substantive theory was constructed and no new information emerged from data collection. The theory that was constructed from the data describes five information practices of teen content creators. The five information practices are learning community, negotiating aesthetic, negotiating control, negotiating capacity, and representing knowledge. In describing the five information practices there are three necessary descriptive components, the community of practice, the experiences of information and the information actions. The experiences of information include information as participation, inspiration, collaboration, process, and artifact. Information actions include activities that occur in the categories of gathering, thinking and creating. The experiences of information and information actions intersect in the information practices, which are situated within the specific community of practice, such as a digital participatory community. Finally, the information practices interact and build upon one another and this is represented in a graphic model and explanation.

A Bayesian approach to the determination of ignition delay

A novel in-cylinder pressure method for determining ignition delay has been proposed and demonstrated. This method proposes a new Bayesian statistical model to resolve the start of combustion, defined as being the point at which the band-pass in-cylinder pressure deviates from background noise and the combustion resonance begins. Further, it is demonstrated that this method is still accurate in situations where there is noise present. The start of combustion can be resolved for each cycle without the need for ad hoc methods such as cycle averaging. Therefore, this method allows for analysis of consecutive cycles and inter-cycle variability studies. Ignition delay obtained by this method and by the net rate of heat release have been shown to give good agreement. However, the use of combustion resonance to determine the start of combustion is preferable over the net rate of heat release method because it does not rely on knowledge of heat losses and will still function accurately in the presence of noise. Results for a six-cylinder turbo-charged common-rail diesel engine run with neat diesel fuel at full, three quarters and half load have been presented. Under these conditions the ignition delay was shown to increase as the load was decreased with a significant increase in ignition delay at half load, when compared with three quarter and full loads.

Ignition delay in an ethanol fumigated common rail diesel engine

A novel method for determining ignition delay is presented. This method utilises combustion resonance as a means of determining the onset of ignition. Results are shown from an ethanol fumigation study comprising of substitutions up to 50% at full, three-quarter and half load. It has been demonstrated that at full load there is a decrease in ignition delay with increasing ethanol substitutions, whereas at half load there is an increase in ignition delay with increasing ethanol substitutions. It is suggested that this conflicting result is a consequence of the auto ignition of ethanol.

The politics and poetics of coexistence : experiments at the intersection of art and environmental engineering

This research project explores how interdisciplinary art practices can provide ways for questioning and envisaging alternative modes of coexistence between humans and the non-humans who together, make up the environment. As a practiceled project, it combines a body of creative work (50%) and this exegesis (50%). My interdisciplinary artistic practice appropriates methods and processes from science and engineering and merges them into artistic contexts for critical and poetic ends. By blending pseudo-scientific experimentation with creative strategies like visual fiction, humour, absurd public performance and scripted audience participation, my work engages with a range of debates around ecology. This exegesis details the interplay between critical theory relating to these debates, the work of other creative practitioners and my own evolving artistic practice. Through utilising methods and processes drawn from my prior career in water engineering, I present an interdisciplinary synthesis that seeks to promote improved understandings of the causes and consequences of our ecological actions and inactions.

An analysis of the KEEP CLEAR pavement markings effects on queuing vehicles dynamic performance at urban signalised intersections

KEEP CLEAR pavement markings are widely used at urban signalised intersections to indicate to drivers to avoid entering blocked intersections. For example, ‘Box junctions’ are most widely used in the United Kingdom and other European countries. However, in Australia, KEEP CLEAR markings are mostly used to improve access from side roads onto a main road, especially when the side road is very close to a signalised intersection. This paper aims to reveal how the KEEP CLEAR markings affect the dynamic performance of the queuing vehicles on the main road, where the side road access is near a signalised intersection. Raw traffic field data was collected from an intersection at the Gold Coast, Australia, and the Kanade–Lucas–Tomasi (KLT) feature tracker approach was used to extract dynamic vehicle data from the raw video footage. The data analysis reveals that the KEEP CLEAR markings generate positive effects on the queuing vehicles in discharge on the main road. This finding refutes the traditional viewpoint that the KEEP CLEAR pavement markings will cause delay for the queuing vehicles’ departure due to the enlarged queue spacing. Further studies are suggested in this paper as well.

Determining operations affected by delay in predictive train timetables

Constructing train schedules is vital in railways. This complex and time consuming task is however made more difficult by additional requirements to make train schedules robust to delays and other disruptions. For a timetable to be regarded as robust, it should be insensitive to delays of a specified level and its performance with respect to a given metric, should be within given tolerances. In other words the effect of delays should be identifiable and should be shown to be minimal. To this end, a sensitivity analysis is proposed that identifies affected operations. More specifically a sensitivity analysis for determining what operation delays cause each operation to be affected is proposed. The information provided by this analysis gives another measure of timetable robustness and also provides control information that can be used when delays occur in practice. Several algorithms are proposed to identify this information and they utilise a disjunctive graph model of train operations. Upon completion the sets of affected operations can also be used to define the impact of all delays without further disjunctive graph evaluations.

Ignition delay of bio-fuels in a common-rail compression ignition engine

The utility of a novel technique for determining the ignition delay in a compression ignition engine has been shown. This method utilises statistical modelling in the Bayesian paradigm to accurately resolve the start of combustion from a band-pass in-cylinder pressure signal. Applied to neat diesel and six biofuels, including four fractionations of palm oil of varying carbon chain length and degree of unsaturation, the relationships between ignition delay, cetane number and oxygen content have been explored. It is noted that the expected negative relationship between ignition delay and cetane number held, as did the positive relationship between ignition delay and oxygen content. The degree of unsaturation was also identified as a potential factor influencing the ignition delay.

Modeling bus rapid transit station bus queuing for operational analysis

This paper presents mathematical models for BRT station operation, calibrated using microscopic simulation modelling. Models are presented for station capacity and bus queue length. No reliable model presently exists to estimate bus queue length. The proposed bus queue model is analogous to an unsignalized intersection queuing model.

The optimal duration and delay of first aid treatment for deep partial thickness burn injuries

Using our porcine model of deep dermal partial thickness burn injury, various durations (10min, 20min, 30min or 1h) and delays (immediate, 10min, 1h, 3h) of 15 degrees C running water first aid were applied to burns and compared to untreated controls. The subdermal temperatures were monitored during the treatment and wounds observed weekly for 6 weeks, for re-epithelialisation, wound surface area and cosmetic appearance. At 6 weeks after the burn, tissue biopsies were taken of the scar for histological analysis. Results showed that immediate application of cold running water for 20min duration is associated with an improvement in re-epithelialisation over the first 2 weeks post-burn and decreased scar tissue at 6 weeks. First aid application of cold water for as little as 10min duration or up to 1h delay still provides benefit.

Public sector project delay : the Malaysian perspective and the way forward

Construction delay has been a protracted problem for the Malaysian construction industry. Recent report showed that 80% of public sector projects are behind schedule. This underachieving time performance has led to many problems including public complaints, loss of reputation and revenue for the government and a slump in the industry’s GDP contribution. Research in the area of project delay has mushroomed worldwide with attempts to place mitigation plans, but delay remains a global phenomenon. There is now an urgent need for revolutionizing construction practices and past research, backed up with few successful cases suggests that Supply Chain Management (SCM) could prove beneficial to reduce or eliminate delays in construction. SCM which originated from the automotive manufacturing industry promotes a more collaborative approach to construction management and has recently gained attention of the construction industry. However every country, including Malaysia, would certainly have disparities of their own compared to others being it from the cultural point of view, nature of problems, locality or improvements needed. Therefore, this paper will present part of a Ph.D. research which aims at illustrating the Malaysian construction industry experts’ perception of the Malaysian public sector project delay, provide insight into these dilemmas, highlights the problems with current practices, its effects and the improvements needed. Subsequently, this paper would propose ratification to the problems using SCM. A semi-structured interview has been conducted to practitioners with at least 20 years’ experience in the industry. The findings showed that Malaysia may be unique compared to other countries and that by considering a number of additional factors, SCM could prove beneficial to increase efficiency of the Malaysian public sector projects.

Using pulse transit delay in Z-scan to discriminate between excited-state absorption and other nonlinear processes in ZnO nanocones

We report a new approach that uses the single beam Z-scan technique, to discriminate between excited state absorption (ESA) and two and three photon nonlinear absorption. By measuring the apparent delay or advance of the pulse in reaching the detector, the nonlinear absorption can be unambiguously identified as either instantaneous or transient. The simple method does not require a large range of input fluences or sophisticated pulse-probe experimental apparatus. The technique is easily extended to any absorption process dependent on pulse width and to nonlinear refraction measurements. We demonstrate in particular, that the large nonlinear absorption in ZnO nanocones when exposed to nanosecond 532 nm pulses, is due mostly to ESA, not pure two-photon absorption.