Visible photoluminescence from plasma-synthesized SiO 2-buffered SiN x films : effect of film thickness and annealing temperature

The effect of the film thickness and postannealing temperature on visible photoluminescence (PL) from Si Nx films synthesized by plasma-assisted radio frequency magnetron sputtering on Si O2 buffer layers is investigated. It is shown that strong visible PL is achieved at annealing temperatures above 650 °C. The optimum annealing temperature for the maximum PL yield strongly depends on the film thickness and varies from 800 to 1200°C. A comparative composition-structure-property analysis reveals that the PL intensity is directly related to the content of the Si-O and Si-N bonds in the Si Nx films. Therefore, sufficient oxidation and moderate nitridation of Si Nx Si O2 films during the plasma-based growth process are crucial for a strong PL yield. Excessively high annealing temperatures lead to weakened Si-N bonds in thinner Si Nx films, which eventually results in a lower PL intensity.

Nano-scale morphology and electron spectrum of defect states in low-k SiOCH films

Results of experimental investigations on the relationship between nanoscale morphology of carbon doped hydrogenated silicon-oxide (SiOCH) low-k films and their electron spectrum of defect states are presented. The SiOCH films have been deposited using trimethylsilane (3MS) - oxygen mixture in a 13.56 MHz plasma enhanced chemical vapor deposition (PECVD) system at variable RF power densities (from 1.3 to 2.6 W/cm2) and gas pressures of 3, 4, and 5 Torr. The atomic structure of the SiOCH films is a mixture of amorphous-nanocrystalline SiO2-like and SiC-like phases. Results of the FTIR spectroscopy and atomic force microscopy suggest that the volume fraction of the SiC-like phase increases from ∼0.2 to 0.4 with RF power. The average size of the nanoscale surface morphology elements of the SiO2-like matrix can be controlled by the RF power density and source gas flow rates. Electron density of the defect states N(E) of the SiOCH films has been investigated with the DLTS technique in the energy range up to 0.6 eV from the bottom of the conduction band. Distinct N(E) peaks at 0.25 - 0.35 eV and 0.42 - 0.52 eV below the conduction band bottom have been observed. The first N(E) peak is identified as originated from E1-like centers in the SiC-like phase. The volume density of the defects can vary from 1011 - 1017 cm-3 depending on specific conditions of the PECVD process.

Detection of dynamic primary user with cooperative spectrum sensing

In this paper we demonstrate that existing cooperative spectrum sensing formulated for static primary users cannot accurately detect dynamic primary users regardless of the information fusion method. Performance error occurs as the sensing parameters calculated by the conventional detector result in sensing performance that violates the sensing requirements. Furthermore, the error is accumulated and compounded by the number of cooperating nodes. To address this limitation, we design and implement the duty cycle detection model for the context of cooperative spectrum sensing to accurately calculate the sensing parameters that satisfy the sensing requirements. We show that longer sensing duration is required to compensate for dynamic primary user traffic.

Electron-accepting conjugated materials based on 2-Vinyl-4,5- dicyanoimidazoles for application in organic electronics

We report the Heck coupling of 2-vinyl-4,5-dicyanoimidazole (vinazene) with selected di- and trihalo aromatics in an effort to prepare linear and branched electron-accepting conjugated materials for application in organic electronics. By selecting the suitable halo-aromatic moiety, it is possible to tune the HOMO - LUMO energy levels, absorption, and emission properties for a specific application. In this regard, materials with strong photoluminescence from blue → green → red are reported that may have potential application in organic light-emitting diodes (OLEDs). Furthermore, derivatives with strong absorption in the visible spectrum, coupled with favorable HOMO-LUMO levels, have been used to prepare promising organic photovoltaic devices (OPVs) when combined with commercially available semiconducting donor polymers.

Emotion recognition of static and dynamic faces in autism spectrum disorder

There is substantial evidence for facial emotion recognition (FER) deficits in autism spectrum disorder (ASD). The extent of this impairment, however, remains unclear, and there is some suggestion that clinical groups might benefit from the use of dynamic rather than static images. High-functioning individuals with ASD (n = 36) and typically developing controls (n = 36) completed a computerised FER task involving static and dynamic expressions of the six basic emotions. The ASD group showed poorer overall performance in identifying anger and disgust and were disadvantaged by dynamic (relative to static) stimuli when presented with sad expressions. Among both groups, however, dynamic stimuli appeared to improve recognition of anger. This research provides further evidence of specific impairment in the recognition of negative emotions in ASD, but argues against any broad advantages associated with the use of dynamic displays.

Health communication: A pilot study comparing perceptions of women with and without high functioning autism spectrum disorder

Research indicates significant health disparities for individuals with autism. Insight into characteristic sensory, cognitive, communication, social, emotional, and behavioural challenges that may influence health communication for patients with autism is vital to address potential disparities. Women with high functioning autism spectrum disorder (ASD) may have specific healthcare needs, and are likely to independently represent themselves and others in healthcare. A pilot study compared perceptions of healthcare experiences for women with and without ASD using on-line survey based on characteristics of ASD likely to influence healthcare. Fifty-eight adult female participants (32 with ASD diagnosis, 26 without ASD diagnosis) were recruited on-line from autism support organisations. Perceptions measured included self-reporting of pain and symptoms, healthcare seeking behaviours, the influence of emotional distress, sensory and social anxiety, maternity experiences, and the influence of autistic status disclosure. Results partially support the hypothesis that ASD women experience greater healthcare challenges. Women with ASD reported greater challenges in healthcare anxiety, communication under emotional distress, anxiety relating to waiting rooms, support during pregnancy, and communication during childbirth. Self-disclosure of diagnostic status and lack of ASD awareness by healthcare providers rated as highly problematic. Results offer detailed insight into healthcare communication and disparities for women with ASD.

Student perceptions: Improving the educational experiences of high school students on the autism spectrum

Listening to and reflecting on the voices and personal stories of adolescent students with an autism spectrum disorder (ASD) is critically important to developing more inclusive approaches to their education. This article considers the experiences of nine adolescents with an ASD on their inclusive education in a large urban secondary school in Australia. These educational experiences were mapped onto four themes emanating from a similar study by Humphrey and Lewis from the United Kingdom. The results from both studies suggest that although students with ASD are having positive and enabling educational experiences, a number of common inhibitors continue to prevent them from taking full advantage of their schooling. By listening to the voices of students with ASD, specific enablers and inhibitors to promoting successful educational experiences are identified, and recommendations for practice are put forward to better support the education not only of students with ASD but all students.

The spectrum of HIV-1 related cancers in South Africa

Despite the high prevalence of infection by the Human Immunodeficiency Virus (HIV) in South Africa, information on its association with cancer is sparse. Our study was carried out to examine the relationship between HIV and a number of cancer types or sites that are common in South Africa. A total of 4,883 subjects, presenting with a cancer or cardiovascular disease at the 3 tertiary referral hospitals in Johannesburg, were interviewed and had blood tested for HIV. Odds ratios associated with HIV infection were calculated by using unconditional logistic regression models for 16 major cancer types where data was available for 50 or more patients. In the comparison group, the prevalence of HIV infection was 8.3% in males and 9.1% in females. Significant excess risks associated with HIV infection were found for Kaposi's sarcoma (OR=21.9, 95% CI=12.5–38.6), non-Hodgkin lymphoma (OR=5.0, 95%CI=2.7–9.5), vulval cancer (OR=4.8, 95%CI=1.9–12.2) and cervical cancer (OR=1.6, 95%CI=1.1–2.3) but not for any of the other major cancer types examined, including Hodgkin disease, multiple myeloma and lung cancer. In Johannesburg, South Africa, HIV infection was associated with significantly increased risks of Kaposi's sarcoma, non-Hodgkin lymphoma and cancers of the cervix and the vulva. The relative risks for Kaposi's sarcoma and non-Hodgkin lymphoma associated with HIV infection were substantially lower than those found in the West.

The challenges of meeting the needs of children with Autism Spectrum Disorders (ASD) during out of hospital interactoins with Paramedics

This poster presents the results of a critical review of the literature on the intersection between paramedic practice with Autism Spectrum Disorder (ASD) and previews the clinical and communication challenges likely to be experienced with these patients. Paramedics in Australia provide 24/7 out-of-hospital care to the community. Although their core business is to provide emergency care, paramedics also provide care for vulnerable people as a consequence of the social, economic or domestic milieu. Little is known about the frequency of use of emergency out-of-hospital services by children with ASD and their families. Similarly, little is known about the attitudes and perceptions of paramedics to children with ASD and their emergency health care. However, individuals with ASD are likely to require paramedic services at some point across the life span and may be more frequent users of health services as a consequence of the challenges they face. The high rate of co-morbidities of people diagnosed with ASD is reported and includes seizure disorders, gastro-intestinal disorders, metabolic disorders, hormonal dysfunction, ear, nose and throat infections, hearing impairment, hypertension, allergies/anaphylaxis, immune disorders, migraine and diabetes, gross/fine motor skill dysfunction, premature birth, birth defects, obesity and mental illness. Individuals with ASD may frequently experience concurrent communication, behaviour and sensory challenges. Consequently, Paramedics can encounter difficulties gathering important patient information which may compromise sensitive care. These interactions occur often in high pressure and emotionally challenging environments, which add to the difficulties in communicating the treatment and transport needs of this population.

Chirp-spread-spectrum-based real time location system for construction safety management: A case study

Observing the working procedure of construction workers is an effective means of maintaining the safety performance of a construction project. It is also difficult to achieve due to a high worker-to-safety-officer ratio. There is an imminent need for the development of a tool to assist in the real-time monitoring of workers, in order to reduce the number of construction accidents. The development and application of a real time locating system (RTLS) based on the Chirp Spread Spectrum (CSS) technique is described in this paper for tracking the real-time position of workers on construction sites. Experiments and tests were carried out both on- and off-site to verify the accuracy of static and dynamic targets by the system, indicating an average error of within one metre. Experiments were also carried out to verify the ability of the system to identify workers’ unsafe behaviours. Wireless data transfer was used to simplify the deployment of the system. The system was deployed in a public residential construction project and proved to be quick and simple to use. The cost of the developed system is also reported to be reasonable (around 1800USD) in this study and is much cheaper than the cost of other RTLS. In addition, the CCS technique is shown to provide an economical solution with reasonable accuracy compared with other positioning systems, such as ultra wideband. The study verifies the potential of the CCS technique to provide an effective and economical aid in the improvement of safety management in the construction industry.

Environmental contributions to autism: Explaining the rise in incidence of autistic spectrum disorders

The incidence of autism spectrum disorders, a heterogenous group of neurodevelopmental disorders is increasing. In response, there has been a concerted effort by researchers to identify environmental risk factors that explain the epidemiological changes seen with autism. Advanced parental age, maternal migrant status, maternal gestational stress, pregnancy and birth complications, maternal obesity and gestational diabetes, maternal vitamin D deficiency, use of antidepressants during gestation and exposure to organochlorine pesticides during pregnancy are all associated with an increased risk of autism. Folic acid use prior to pregnancy may reduce the risk of autism. Exposure to antenatal ultrasonography, maternal gestational cigarette and alcohol use do not appear to influence the risk of autism in offspring. There is little evidence that exposure to environmental toxins such as thimerosal, polybrominated diphenyl ethers and di-(2-ethylhexyl) phthalate in early childhood increases the risk of autism. Apart from birth complications, the current evidence suggests that the majority of environmental factors increasing the risk of autism occur in the antenatal period. Consistent with the rise in incidence in autism, some of these environmental factors are now more common in developed nations. Further research is required to determine how these environmental exposures translate to an increased risk of autism. Understanding how these exposures alter neurodevelopment in autistic children may inform both the aetiopathogenesis and the strategies for prevention of autism.

Teaching children who have a diagnosis of Autism Spectrum Disorder

Best practice dictates that the Autism Spectrum Disorder (ASD) diagnostic process is informed by experienced professionals from at least two disciplines, for example psychology or speech pathology, with the diagnosis ultimately provided by a specialist medical practitioner e.g. child psychiatrist, neurologist or paediatrician. Irrespective of a child’s age, diagnosis relies upon information about their early development. Current information and observations on a child’s behaviour, communication and socialisation are considered by the specialist medical practitioner against the signs and symptoms detailed in one of several diagnostic systems. Two recently used classification systems in Australia have been the fourth edition of the Diagnostic Statistical Manual of Mental Disorders (DSM-IV) published by the American Psychiatric Association (1994) and the tenth edition of the International Classification of Disease (ICD-10), published by the World Health Organisation (2003).