Beyond an Uncertain Future: Vietnamese Parents of Children with Autism Spectrum Disorders and Their Needs for Social Support

While Vietnamese parents of children with Autism Spectrum Disorders (ASD) experience great uncertainty and stress about their children’s development and adjustment to adult life, they have not received sufficient support. This study aims to identify the specific needs for social support of Vietnamese parents of children with autism. To carry out the study, I conducted ten ethnographic interviews with parents of children with ASD who lived in urban areas within Vietnam. The findings of this study led to four main conclusions. First, the parents’ needs for informational, instrumental, and emotional support varied according to their children’s age and level of ASD severity. Second, instrumental support was the most desirable type of functional support for the parents. Third, my study discovered the significant role of other parents of children with ASD in providing support for the ten participants. Lastly, the study recognized the parents’ high expectations for social support from the Vietnamese government and non-governmental organizations

Supercritical pyrolysis of toluene

The development of future high-speed aircrafts will required the jet fuel to act as the primary engine coolant to absorb excess heat produced by the engine components. To aid in removing the excess heat and reducing the aircraft’s weight, future jet fuels used for high-speed aircrafts will act as both coolant and fuel; however, by exposing the fuels to temperatures and pressures above their critical point, they undergo pyrolysis to form larger and/or more abundant polycyclic aromatic hydrocarbons (PAH) and eventually carbonaceous solid deposits in the pre-combustion environment. The formation of solid deposits in the pre-combustion environment results in clogging of the fuel line, reduced engine performance, and meticulous engine maintenance, so it is important to understand the mechanisms leading to the formation of carbonaceous solid deposits from thermally stressed hydrocarbons. Using a flow reactor, an investigation was conducted to understand the reaction mechanisms leading to the formation of PAH, which are known to be precursors to solid deposits. The reactant toluene, selected to be a representative of the aromatic components of real-world jet fuels, was pyrolyzed in a flow reactor under supercritical conditions, with temperature conditions between 550 and 685 C and pressure conditions between 50 and 100 atm. Identification and quantification of the gas- and liquid-phase samples are conducted using gas chromatography (GC) with flame ionization detection and high-pressure liquid chromatography (HPLC) with diode-array ultraviolet-visible (UV) detection – the liquid-phase GC and HPLC are in series with mass spectrometry (MS). Identification using gas-phase GC, liquid-phase GC, and HPLC revealed the formation of 60 hydrocarbon (aliphatic and aromatic) products, of which three unsubstituted PAH products have never before been identified as products of toluene pyrolysis. Furthermore, temperature and pressure dependent yields of the identified hydrocarbon products are presented. The formation of gaseous products as well as aromatic products in the supercritical toluene pyrolysis environment is the result of decomposition of toluene, recombination of unstable molecule fragments, dehydrogenation of aromatic products, and/or successive addition of aromatic molecules to low-ring-number aromatic products. At high thermally stressed conditions the formation of increasingly high molecular PAH becomes insoluble in the fuel and forms a distinct solid phase, carbonaceous solid deposits

Optical characterisation of quantum well infrared photodetectors (QWIPs) for gas sensing applications

Although much work has been done on λ∼5-12 μm quantum well infrared photodetectors (QvWPs), the distinctive feature of this project is the use of strain compensated materials on InP substrates, AIAs (tensile) and InGaAs (compressive), to achieve shorter wavelengths and higher temperature operation. Stepped wells, high thin barriers, and strained layers have been used to achieve λ∼2-5 μm and also enhanced normal incidence absorption. These structures also give an additional degree of freedom to control the position of the excited states in the QWIPs conduction band. The strain-balancing allows the use of Indium (In) concentrations up to 84% and hence deep wells with a large band offset relative to the outer barrier (which predominantly controls the dark current). The conduction band offset (ΔEc) for these structures (with respect to the wide InAlAs barrier) is estimated to be ∼675 meV. In the course of this work, we have also been able to estimate the subband nonparabolicity (m* and α) from absorption spectra in highly doped quantum wells (QWs).In this thesis, the main results which I present are on a comparative study of the intersubband absorption in a series of double barrier QW (DBQW) structures grown on GaAs substrates (Chapter 5) and InP substrates (Chapter 6). The background and theory of QWs is given in Chapter 1. In Chapter 2, the experimental procedure is detailed, while the theoretical model to calculate the conduction band profile and energy levels and the comparison of this model with literature values are presented in Chapter 3. Early results are discussed in Chapter 4. Finally, a summary and future work are outlined in Chapter 7

What Cultural Themes Are Present in the 28th Season of The Simpsons?

This project seeks to determine the cultural themes reflected in the 28th season of The Simpsons, a worldwide popular animated TV show about a stereotypical American household living in the fictional town of Springfield, through the qualitative research method of textual analysis. Preceding research, including Keazor’s (2011) article on how The Simpsons use meta-reference to make jokes and Lewis’s (2002) work on its double-coded portrayal of a sensitive subject namely religion, are examined. The sample size of 22 episodes of season 28 was accessed through purchase on Amazon, and each researcher watched the show separately and repeatedly until theoretical saturation was reached. Major cultural themes found in season 28 are Reliance on technology, including every instance when The Simpsons parodies existing technological trends such as virtual reality, over-reliance on mobile apps and obsession with mobile games; Parodies of existing movies & TV shows, including Adventure Time, Planet of The Apes, The Hunger Games and Goldfinger; and Breaches of the 4th wall, most notably within every episode’s opening, specifically in the intro couch gag

Fitting Structural Equation Models via Variational Approximations

Structural equation models are commonly used to capture the relationship between sets of observed and unobservable variables. Traditionally these models are fitted using frequentist approaches but recently researchers and practitioners have developed increasing interest in Bayesian inference. In Bayesian settings, inference for these models is typically performed via Markov chain Monte Carlo methods, which may be computationally intensive for models with a large number of manifest variables or complex structures. Variational approximations can be a fast alternative; however, they have not been adequately explored for this class of models. We develop a mean field variational Bayes approach for fitting elemental structural equation models and demonstrate how bootstrap can considerably improve the variational approximation quality. We show that this variational approximation method can provide reliable inference while being significantly faster than Markov chain Monte Carlo

Subsampling MCMC - An introduction for the survey statistician

The rapid development of computing power and efficient Markov Chain Monte Carlo (MCMC) simulation algorithms have revolutionized Bayesian statistics, making it a highly practical inference method in applied work. However, MCMC algorithms tend to be computationally demanding, and are particularly slow for large datasets. Data subsampling has recently been suggested as a way to make MCMC methods scalable on massively large data, utilizing efficient sampling schemes and estimators from the survey sampling literature. These developments tend to be unknown by many survey statisticians who traditionally work with non-Bayesian methods, and rarely use MCMC. Our article explains the idea of data subsampling in MCMC by reviewing one strand of work, Subsampling MCMC, a so called pseudo-marginal MCMC approach to speeding up MCMC through data subsampling. The review is written for a survey statistician without previous knowledge of MCMC methods since our aim is to motivate survey sampling experts to contribute to the growing Subsampling MCMC literature.Comment: Accepted for publication in Sankhya A. Previous uploaded version contained a bug in generating the figures and reference