Analysis and correction of voltage profile in low voltage distribution networks containing photovoltaic cells and electric vehicles

Voltage drop and rise at network peak and off–peak periods along with voltage unbalance are the major power quality problems in low voltage distribution networks. Usually, the utilities try to use adjusting the transformer tap changers as a solution for the voltage drop. They also try to distribute the loads equally as a solution for network voltage unbalance problem. On the other hand, the ever increasing energy demand, along with the necessity of cost reduction and higher reliability requirements, are driving the modern power systems towards Distributed Generation (DG) units. This can be in the form of small rooftop photovoltaic cells (PV), Plug–in Electric Vehicles (PEVs) or Micro Grids (MGs). Rooftop PVs, typically with power levels ranging from 1–5 kW installed by the householders are gaining popularity due to their financial benefits for the householders. Also PEVs will be soon emerged in residential distribution networks which behave as a huge residential load when they are being charged while in their later generation, they are also expected to support the network as small DG units which transfer the energy stored in their battery into grid. Furthermore, the MG which is a cluster of loads and several DG units such as diesel generators, PVs, fuel cells and batteries are recently introduced to distribution networks. The voltage unbalance in the network can be increased due to the uncertainties in the random connection point of the PVs and PEVs to the network, their nominal capacity and time of operation. Therefore, it is of high interest to investigate the voltage unbalance in these networks as the result of MGs, PVs and PEVs integration to low voltage networks. In addition, the network might experience non–standard voltage drop due to high penetration of PEVs, being charged at night periods, or non–standard voltage rise due to high penetration of PVs and PEVs generating electricity back into the grid in the network off–peak periods. In this thesis, a voltage unbalance sensitivity analysis and stochastic evaluation is carried out for PVs installed by the householders versus their installation point, their nominal capacity and penetration level as different uncertainties. A similar analysis is carried out for PEVs penetration in the network working in two different modes: Grid to vehicle and Vehicle to grid. Furthermore, the conventional methods are discussed for improving the voltage unbalance within these networks. This is later continued by proposing new and efficient improvement methods for voltage profile improvement at network peak and off–peak periods and voltage unbalance reduction. In addition, voltage unbalance reduction is investigated for MGs and new improvement methods are proposed and applied for the MG test bed, planned to be established at Queensland University of Technology (QUT). MATLAB and PSCAD/EMTDC simulation softwares are used for verification of the analyses and the proposals.

The 'obesity paradox' in chronic obstructive pulmonary disease

Poor nutritional status in chronic obstructive pulmonary disease (COPD) is associated with increased mortality independently of disease-severity (Collins et al).1 Epidemiological studies have suggested a protective role of obesity against mortality in COPD (Vestbo et al)2 which is contrary to data from the general population where obesity is associated with decreased life expectancy. This relationship has been referred to as the ‘obesity paradox’ and has been demonstrated in a number of chronic wasting conditions (Kalantar-Zadeh et al).3 This study investigated the existence of the obesity paradox in outpatients with COPD by examining the effect of body mass index (BMI) on 1-year healthcare use and clinical outcome in terms of hospital admission rates, length of hospital stay, outpatient appointments and mortality. BMI was assessed in 424 outpatients with COPD, with measurements performed by specialist respiratory nurses during outpatient clinics. 1-year healthcare use was retrospectively collected from the date of BMI measurement. Abstract S163 Table 1 Patients classified as overweight (25.0–29.9 kg/m2) or obese (>30 kg/m2) experienced significantly fewer emergency hospital admissions, as well as a reduced length of hospital stay, in comparison to normal weight (20.0–24.9 kg/m2) or underweight (<20 kg/m2) outpatients. There was a significant negative trend between BMI classification and mortality. This study supports the existence of the ‘obesity paradox’ in COPD, not only in relation to reduced 1 year mortality rates but also in terms of reduced emergency hospital admissions and reduced length of hospital stay.

P147 Deprivation is associated with increased healthcare utilisation in patients with chronic obstructive pulmonary disease

Deprivation assessed using the index of multiple deprivation (IMD) has been shown to be an independent risk factor for 1-year mortality in outpatients with chronic obstructive pulmonary disease; COPD (Collins et al, 2010). IMD combines a number of economic and social issues (eg, health, education, employment) into one overall deprivation score, the higher the score the higher an individual's deprivation. Whilst malnutrition in COPD has been linked to increased healthcare use it is not clear if deprivation is also independently associated. This study aimed to investigate the influence of deprivation on 1-year healthcare utilisation in outpatients with COPD. IMD was established in 424 outpatients with COPD according to the geographical location for each patient's address (postcode) and related to their healthcare use in the year post-date screened (Nobel et al, 2008). Patients were routinely screened in outpatient clinics for malnutrition using the ‘Malnutrition Universal Screening Tool’, ‘MUST’ (Elia 2003); mean age 73 (SD 9.9) years; body mass index 25.8 (SD 6.3) kg/m2 with healthcare use collected 1 year from screening (Abstract P147 Table 1). Deprivation assessed using IMD (mean 15.9; SD 11.1) was found to be a significant predictor for the frequency and duration of emergency hospital admissions as well as the duration of elective hospital admission. Deprivation was also linked to reduced secondary care outpatient appointment attendance but not an increase in failure to attend and deprivation was not associated with increased disease severity, as classified by the GOLD criteria (p=0.580). COPD outpatients residing in more deprived areas experience increased hospitalisation rates but decreased outpatient appointment attendance. The underlying reason behind this disparity in healthcare use requires further investigation.

Early users of fertility treatment with hormones and IVF : women who live in major cities and have private health insurance

Objective: To identify early users (women aged <34 years) of fertility treatment with hormones and in vitro fertilisation (IVF). Methods: A cross-sectional survey of infertile women from fertility clinics (n=59) and from the community (Australian Longitudinal Study on Women's Health participants) who had (n=121) or had not (n=110) used hormones/IVF as treatment for infertility. Associations between socio-demographic, reproductive and lifestyle factors, medical conditions and recurrent symptoms and using treatment (or not) were analysed using multivariable logistic regression. Results: Among infertile women who had used treatment (community vs clinic), women from clinics had lower odds of living outside major cities, using hormones only, i.e., not IVF, or recurrent headaches/migraines, severe tiredness, or stiff/painful joints; and higher odds of recent diagnoses of urinary tract infection or anxiety disorder. Compared to infertile women who had not used treatment, women from clinics had lower odds of living outside major cities, recurrent allergies or severe tiredness; and higher odds of having private health insurance for hospital or ancillary services, recent diagnosis of polycystic ovary syndrome or recurrent constipation. Conclusions: Compared to infertile women in the community, living in major cities and having private health insurance are associated with early use of treatment for infertility at specialist clinics by women aged <34 years. Implications: These results provided evidence of inequity of services for infertile women.

Fertility and infertility : studies in reproductive epidemiology in Australia

Worldwide, there are few large-scale epidemiological studies on infertility. In Australia, population-based research on infertility is limited to a few small-scale studies. Therefore, the prevalence of infertility and unmet need for specialist medical advice and treatment cannot be estimated reliably. Women who have used assisted reproductive technologies (ART) are recorded in treatment registries. However, there are many infertile women who are excluded from these clinical populations because they neither seek advice nor use treatment. The thesis was based on a biopsychosocial model of health and used the methods of reproductive epidemiology to address the lack of national data on the prevalence of infertility in Australia. Firstly, numbers of births and pregnancy losses were investigated in two generations of women participating in the Australian Longitudinal Study on Women’s Health (ALSWH). The ALSWH is a broad-ranging, longitudinal examination of biological, psychological and social factors that impact on women’s health and wellbeing. Women from three age cohorts were randomly sampled from the population using the universal public health insurance (i.e., Medicare) database and ALSWH participants were representative of the female population. However, the studies in the thesis only involved data from two cohorts. The younger cohort were born in 1973-78 and completed up to four mailed surveys between 1996 (when they were aged 18-23 years, n=14247) and 2006 (28-33 years, n=9145). The mid-aged cohort were born in 1946-51 and completed four mailed surveys between 1996 (when they were aged 45-50 years n=13715) and 2004 (53-58 years, n=10905). Compared to other studies that focus on outcomes of single pregnancies, these studies included all pregnancy outcomes by developing comprehensive reproductive histories for each woman. Pregnancy outcomes included birth, miscarriage, stillbirth, termination and ectopic pregnancy. Women in the youngest cohort (born in 1973-78) were only just reaching their peak childbearing years and many (44%) had yet to report their first pregnancy outcome. Women from the mid-aged cohort (born 1946-51) had completed their reproductive lives and 92% were able to report on their lifetime pregnancy outcomes. Pregnancy losses, especially miscarriage, were common for both generations of women. Secondly, the prevalence of infertility, seeking medical advice and using treatment was identified for these two generations of women. For the older generation, the lifetime prevalence of infertility and demand for treatment was investigated in the context of the specialist medical services which became available circa 1980. By this time, however, most of these older women had already been pregnant and completed their families. For women who experienced infertility (11%), their options for advice and treatment were limited and less than half (42%) had used any treatment. More recently for the younger generation of women, who were aged 28-33 years in 2006, specialist advice and treatment were extensively available. Among women who had tried to conceive or had been pregnant (n=5936), 17% had experienced infertility and the majority (72%) were able to access medical advice. However, after seeking advice only half of these infertile women had used treatment with fertility hormones or in vitro fertilisation (IVF). Overall for infertile women aged up to 33 years, only one-third had used these treatments. Thirdly, the barriers to accessing medical advice and using treatment for infertility were identified for women aged less than 34 years. Among a community sample of infertile women aged 28-33 years (ALSWH participants), self-reported depression was found to be a barrier to accessing medical advice. The characteristics of these infertile women in the community who had (n=121) or had not (n=110) used treatment were compared to infertile women aged 27-33 years (n=59) attending four fertility clinics. Compared to infertile women in the community, living in major cities and having private health insurance were associated with early use of treatment for infertility at specialist clinics by women aged <34 years. In contrast to most clinical studies of IVF, the final study reported in the thesis took into account repeated IVF cycles and the impact of women’s individual histories on IVF outcomes. Among 121 infertile women (aged 27-46 years) who had 286 IVF cycles, older age and prolonged use of the oral contraceptive pill were associated with fewer eggs collected. Further, women in particular occupations had lower proportions of eggs fertilised normally than women in other occupational groups. These studies form the first large-scale epidemiological examination of infertility in Australia. The finding that two-thirds of women with infertility had not used treatment indicates that there is an unmet need for specialist treatment in women aged less than 34 years. However, barriers to accessing treatment prevent women using ART at a younger age when there is a higher chance of pregnancy.

A limb lost every 3 hours: can Australia reduce amputations in people with diabetes?

Recommendations to improve national diabetes-related foot disease (DRFD) care • National data collection on incidence and outcomes of DRFD. • Improved access to care, through the Medicare Benefits Schedule, for people with diabetes who have a current or past foot complication. • Standardised national model for interdisciplinary DRFD care. • National accreditation of interdisciplinary foot clinics and staff. • Subsidies for evidence-based treatments for DRFD, including medical-grade footwear and pressure off-loading devices. • Holistic diabetes care initiatives to “close the gap” on inequities in health outcomes for Aboriginal and Torres Strait Islander peoples.

Community-based asylum seekers’ use of primary health care services in Melbourne

Objective: To investigate primary health care service utilisation and health presentations among asylum seekers living in Melbourne. Design and setting: Retrospective audit of files of people who attended three Melbourne asylum-seeker health clinics between 1 July 2005 and 30 June 2006. Main outcome measures: Rates of reasons for the encounter, diagnostic tests or investigations required, treatments prescribed and referrals. Results: Data were collected from 998 consultations corresponding to 341 people. Eighty-eight per cent of visits involved people with no Medicare access, owing to their visa status. The most common reasons for the encounter were general and unspecified symptoms or problems (rate, 59.9 per 100 encounters; 95% CI, 55–65), followed by musculoskeletal conditions (27.1; 95% CI, 24–30), and psychological problems (26.5; 95% CI, 23–30). The rate of referrals was 18.3 per 100 encounters (95% CI, 16–21). Conclusions: The three clinics providing services to asylum seekers in Melbourne are delivering care to a considerable number of people with complex health needs. A substantial number of asylum seekers present to clinics with psychological and social problems. Most cannot access government-subsidised health care. This must be addressed urgently by policy change at the federal and state and territory levels.

Assessing Cardiovascular Risk in Regional Areas: The Healthy Hearts – Beyond City Limits Program

Background: Cardiovascular disease (CVD) is more prevalent in regional and remote Australia compared to metropolitan areas. The aim of Healthy Hearts was to determine age and sex specific CVD risk factor levels and the potential value of national risk clinics. Methods: Healthy Hearts was an observational research study conducted in four purposefully selected higher risk communities in regional Victoria, Australia. The main outcome measures were the proportion of participants with CVD risk factors with group comparisons to determine the adjusted likelihood of elevated risk factor levels. Trained personnel used a standardized protocol over four weeks per community to measure CVD risk factor levels, estimate absolute CVD risk and provide feedback and advice. Results: A total of 2125 self-selected participants were assessed (mean age 58 ± 15 years, 57% women). Overall, CVD risk factors were highly prevalent. More men than women had ≥ 2 modifiable CVD risk factors (76% vs. 68%, p < .001), pre-existing CVD (20 vs. 15%, p < .01) and a major ECG abnormality requiring follow-up (15% vs. 7%, p < .001) . Less men reported depressive symptoms compared to women (28% vs. 22%, p < .01). A higher proportion of women were obese (adjusted OR 1.36, 95% CI 1.13 to 1.63), and physically inactive (adjusted OR 1.32, 95% CI 1.07 to 1.63). Conclusions: High CVD risk factor levels were confirmed for regional Victoria. Close engagement with individuals and communities provides scope for the application of regional risk management clinics to reduce the burden of CVD risk in regional Australia.

Saturated core high-temperature superconducting fault current limiters as an alternative to conventional series reactors in a distribution grid

Series reactors are used in distribution grids to reduce the short-circuit fault level. Some of the disadvantages of the application of these devices are the voltage drop produced across the reactor and the steep front rise of the transient recovery voltage (TRV), which generally exceeds the rating of the associated circuit breaker. Simulations were performed to compare the characteristics of a saturated core High-Temperature Superconducting Fault Current Limiter (HTS FCL) and a series reactor. The design of the HTS FCL was optimized using the evolutionary algorithm. The resulting Pareto frontier curve of optimum solution is presented in this paper. The results show that the steady-state impedance of an HTS FCL is significantly lower than that of a series reactor for the same level of fault current limiting. Tests performed on a prototype 11 kV HTS FCL confirm the theoretical results. The respective transient recovery voltages (TRV) of the HTS FCL and an air core reactor of comparable fault current limiting capability are also determined. The results show that the saturated core HTS FCL has a significantly lower effect on the rate of rise of the circuit breaker TRV as compared to the air core reactor. The simulations results are validated with shortcircuit test results.

Perceived barriers to healthy lifestyle activities in midlife and older Australian women with type 2 diabetes

Purpose: Type 2 diabetes is a leading cause of morbidity and mortality in midlife and older Australian women with known modifiable risk factors for type 2 diabetes including smoking, nutrition, physical activity and obesity. In Australia little research has been done to investigate the perceived barriers to healthy lifestyle activities in midlife and older women with type 2 diabetes. The primary aim of this study was to explore the level and type of perceived barriers to health promotion activities. The secondary aim was to explore the relationship of perceived barriers to smoking behaviour, fruit and vegetable intake, physical activity, and body mass index. Methods: The study was a cross sectional survey of women, aged over 45 with type 2 diabetes, attending metropolitan community health clinics (N = 41). Data was collected from self-report questionnaire and analysed using descriptive and inferential statistics. Results: Women in the study had average total barriers scores similar to those reported in the literature for women with a range of physical disabilities and illnesses. The leading barriers for this group of women were: lack of interest, concern about safety, too tired, lack of money and feeling what they do does not help. There was no association between total barriers scores and body mass index, physical activity, fruit and vegetable intake or socio-demographic variables. Conclusion: This study contributes to understanding the perceptions of midlife and older women with type 2 diabetes about the level and type of barriers to healthy lifestyle activities that they experience. Evidence from this study can be applied to inform health promotion for lifestyle risk factor reduction in women with type 2 diabetes.

The relationship between anti-mullerian hormone in women receiving fertility assessments and age at menopause in subfertile women : evidence from large population studies

Context: Anti-Müllerian hormone (AMH) concentration reflects ovarian aging and is argued to be a useful predictor of age at menopause (AMP). It is hypothesized that AMH falling below a critical threshold corresponds to follicle depletion, which results in menopause. With this threshold, theoretical predictions of AMP can be made. Comparisons of such predictions with observed AMP from population studies support the role for AMH as a forecaster of menopause. Objective: The objective of the study was to investigate whether previous relationships between AMH and AMP are valid using a much larger data set. Setting: AMH was measured in 27 563 women attending fertility clinics. Study Design: From these data a model of age-related AMH change was constructed using a robust regression analysis. Data on AMP from subfertile women were obtained from the population-based Prospect-European Prospective Investigation into Cancer and Nutrition (Prospect- EPIC) cohort (n � 2249). By constructing a probability distribution of age at which AMH falls below a critical threshold and fitting this to Prospect-EPIC menopausal age data using maximum likelihood, such a threshold was estimated. Main Outcome: The main outcome was conformity between observed and predicted AMP. Results: To get a distribution of AMH-predicted AMP that fit the Prospect-EPIC data, we found the critical AMH threshold should vary among women in such a way that women with low age-specific AMH would have lower thresholds, whereas women with high age-specific AMH would have higher thresholds (mean 0.075 ng/mL; interquartile range 0.038–0.15 ng/mL). Such a varying AMH threshold for menopause is a novel and biologically plausible finding. AMH became undetectable (�0.2 ng/mL) approximately 5 years before the occurrence of menopause, in line with a previous report. Conclusions: The conformity of the observed and predicted distributions of AMP supports the hypothesis that declining population averages of AMH are associated with menopause, making AMH an excellent candidate biomarker for AMP prediction. Further research will help establish the accuracy of AMH levels to predict AMP within individuals.

Aerosol mass spectrometric analysis of the chemical composition of non- refractory PM1 samples from school environments in Brisbane, Australia

Long term exposure to vehicle emissions has been associated with harmful health effects. Children are amongst the most susceptible group and schools represent an environment where they can experience significant exposure to vehicle emissions. However, there are limited studies on children’s exposure to vehicle emissions in schools. The aim of this study was to quantify the concentration of organic aerosol and in particular, vehicle emissions that children are exposed to during school hours. Therefore an Aerodyne compact time-of-flight aerosol mass spectrometer (TOF-AMS) was deployed at five urban schools in Brisbane, Australia. The TOF-AMS enabled the chemical composition of the non- refractory (NR-PM1) to be analysed with a high temporal resolution to assess the concentration of vehicle emissions and other organic aerosols during school hours. At each school the organic fraction comprised the majority of NR-PM1 with secondary organic aerosols as the main constitute. At two of the schools, a significant source of the organic aerosol (OA) was slightly aged vehicle emissions from nearby highways. More aged and oxidised OA was observed at the other three schools, which also recorded strong biomass burning influences. Primary emissions were found to dominate the OA at only one school which had an O:C ratio of 0.17, due to fuel powered gardening equipment used near the TOF-AMS. The diurnal cycle of OA concentration varied between schools and was found to be at a minimum during school hours. The major organic component that school children were exposed to during school hours was secondary OA. Peak exposure of school children to HOA occurred during school drop off and pick up times. Unless a school is located near major roads, children are exposed predominately to regional secondary OA as opposed to local emissions during schools hours in urban environments.

Factors associated with suboptimal adherence to antiretroviral therapy in Viet Nam: A cross-sectional study using audio computer-assisted self-interview (ACASI)

Background: Optimal adherence to antiretroviral therapy (ART) is necessary for people living with HIV/AIDS (PLHIV). There have been relatively few systematic analyses of factors that promote or inhibit adherence to antiretroviral therapy among PLHIV in Asia. This study assessed ART adherence and examined factors associated with suboptimal adherence in northern Viet Nam. Methods: Data from 615 PLHIV on ART in two urban and three rural outpatient clinics were collected by medical record extraction and from patient interviews using audio computer-assisted self-interview (ACASI). Results: The prevalence of suboptimal adherence was estimated to be 24.9% via a visual analogue scale (VAS) of past-month dose-missing and 29.1% using a modified Adult AIDS Clinical Trial Group scale for on-time dose-taking in the past 4 days. Factors significantly associated with the more conservative VAS score were: depression (p < 0.001), side-effect experiences (p < 0.001), heavy alcohol use (p = 0.001), chance health locus of control (p = 0.003), low perceived quality of information from care providers (p = 0.04) and low social connectedness (p = 0.03). Illicit drug use alone was not significantly associated with suboptimal adherence, but interacted with heavy alcohol use to reduce adherence (p < 0.001). Conclusions: This is the largest survey of ART adherence yet reported from Asia and the first in a developing country to use the ACASI method in this context. The evidence strongly indicates that ART services in Viet Nam should include screening and treatment for depression, linkage with alcohol and/or drug dependence treatment, and counselling to address the belief that chance or luck determines health outcomes.

The implications of cross-regional differences for the design of In-vehicle Information Systems : a comparison of Australian and Chinese drivers

The increasing global distribution of automobiles necessitates that the design of In-vehicle Information Systems (IVIS) is appropriate for the regions to which they are being exported. Differences between regions such as culture, environment and traffic context can influence the needs, usability and acceptance of IVIS. This paper describes two studies aimed at identifying regional differences in IVIS design needs and preferences across drivers from Australia and China to determine the impact of any differences on IVIS design. Using a questionnaire and interaction clinics, the influence of cultural values and driving patterns on drivers' preferences for, and comprehension of, surface- and interaction-level aspects of IVIS interfaces was explored. Similarities and differences were found between the two regional groups in terms of preferences for IVIS input control types and labels and in the comprehension of IVIS functions. Specifically, Chinese drivers preferred symbols and Chinese characters over English words and were less successful (compared to Australians) at comprehending English abbreviations, particularly for complex IVIS functions. Implications in terms of the current trend to introduce Western-styled interfaces into other regions with little or no adaptation are discussed.

Identification of symptom clusters in patients with chronic venous leg ulcers

Context Patients with venous leg ulcers experience multiple symptoms, including pain, depression, and discomfort from lower leg inflammation and wound exudate. Some of these symptoms impair wound healing and decrease quality of life (QOL). The presence of co-occurring symptoms may have a negative effect on these outcomes. The identification of symptom clusters could potentially lead to improvements in symptom management and QOL. Objectives To identify the prevalence and severity of common symptoms and the occurrence of symptom clusters in patients with venous leg ulcers. Methods For this secondary analysis, data on sociodemographic characteristics, medical history, venous history, ulcer and lower limb clinical characteristics, symptoms, treatments, healing, and QOL were analyzed from a sample of 318 patients with venous leg ulcers who were recruited from hospital outpatient and community nursing clinics for leg ulcers. Exploratory factor analysis was used to identify symptom clusters. Results Almost two-thirds (64%) of the patients experienced four or more concurrent symptoms. The most frequent symptoms were sleep disturbance (80%), pain (74%), and lower limb swelling (67%). Sixty percent of patients reported three or more symptoms at a moderate-to-severe level of intensity (e.g., 78% reported disturbed sleep frequently or always; the mean pain severity score was 49 of 100, SD 26.5). Exploratory factor analysis identified two symptom clusters: pain, depression, sleep disturbance, and fatigue; and swelling, inflammation, exudate, and fatigue. Conclusion Two symptom clusters were identified in this sample of patients with venous leg ulcers. Further research is needed to verify these symptom clusters and to evaluate their effect on patient outcomes.