Anticipating the use of life extension technologies : possible pointers from the adoption of assisted reproductive technologies

The first effective life extension technologies might well become available within the next few years. Experts from the University of Queensland, Australia, explore the possible public reaction to these therapies and the ethical and social concerns they raise, drawing on the experience of assisted reproduction technologies

Contraceptive changes after reproductive events among Australian women born in 1973 to 1978: A longitudinal study from 1996 to 2009

Background Women change contraception as they try to conceive, space births, and limit family size. This longitudinal analysis examines contraception changes after reproductive events such as birth, miscarriage or termination among Australian women born from 1973 to 1978 to identify potential opportunities to increase the effectiveness of contraceptive information and service provision. Methods Between 1996 and 2009, 5,631 Australian women randomly sampled from the Australian universal health insurance (Medicare) database completed five self-report postal surveys. Three longitudinal logistic regression models were used to assess the associations between reproductive events (birth only, birth and miscarriage, miscarriage only, termination only, other multiple events, and no new event) and subsequent changes in contraceptive use (start using, stop using, switch method) compared with women who continued to use the same method. Results After women experienced only a birth, or a birth and a miscarriage, they were more likely to start using contraception. Women who experienced miscarriages were more likely to stop using contraception. Women who experienced terminations were more likely to switch methods. There was a significant interaction between reproductive events and time indicating more changes in contraceptive use as women reach their mid-30s. Conclusion Contraceptive use increases after the birth of a child, but decreases after miscarriage indicating the intention for family formation and spacing between children. Switching contraceptive methods after termination suggests these pregnancies were unintended and possibly due to contraceptive failure. Women’s contact with health professionals around the time of reproductive events provides an opportunity to provide contraceptive services.

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.

Vaccination to protect against infection of the female reproductive tract

Infection of the female genital tract can result in serious morbidities and mortalities from reproductive disability, pelvic inflammatory disease and cancer, to impacts on the fetus, such as infant blindness. While therapeutic agents are available, frequent testing and treatment is required to prevent the occurrence of the severe disease sequelae. Hence, sexually transmitted infections remain a major public health burden with ongoing social and economic barriers to prevention and treatment. Unfortunately, while there are two success stories in the development of vaccines to protect against HPV infection of the female reproductive tract, many serious infectious agents impacting on the female reproductive tract still have no vaccines available. Vaccination to prevent infection of the female reproductive tract is an inherently difficult target, with many impacting factors, such as appropriate vaccination strategies/mechanisms to induce a suitable protective response locally in the genital tract, variation in the local immune responses due to the hormonal cycle, selection of vaccine antigen(s) that confers effective protection against multiple variants of a single pathogen (e.g., the different serovars of Chlamydia trachomatis) and timing of the vaccine administration prior to infection exposure. Despite these difficulties, there are numerous ongoing efforts to develop effective vaccines against these infectious agents and it is likely that this important human health field will see further major developments in the next 5 years.

Factors affecting technical efficiency of rice farmers in village reservoir irrigation systems of Sri Lanka

Given the importance of water for rice production, this study examines the factors affecting the technical efficiency (TE) of irrigated rice farmers in village irrigation systems (VIS) in Sri Lanka. Primary data were collected from 460 rice farmers in the Kurunagala District, Sri Lanka, to estimate a stochastic translog production frontier for rice production. The mean TE of rice farming in village irrigation was found to be 0.72, although 63% of rice farmers exceeded this average. The most influential factors of TE are membership of Farmer Organisations (FOs) and the participatory rate in collective actions organised by FOs. The results suggest that enhancement of co-operative arrangements of farmers by strengthening the membership of FOs is considered important for increasing TE in rice farming in VIS.

The impact of anxiety on processing efficiency : implications for the attentional control theory

The Attentional Control Theory (ACT) proposes that high-anxious individuals maintain performance effectiveness (accuracy) at the expense of processing efficiency (response time), in particular, the two central executive functions of inhibition and shifting. In contrast, research has generally failed to consider the third executive function which relates to the function of updating. In the current study, seventy-five participants completed the Parametric Go/No-Go and n-back tasks, as well as the State-Trait Anxiety Inventory in order to explore the effects of anxiety on attention. Results indicated that anxiety lead to decay in processing efficiency, but not in performance effectiveness, across all three Central Executive functions (inhibition, set-shifting and updating). Interestingly, participants with high levels of trait anxiety also exhibited impaired performance effectiveness on the n-back task designed to measure the updating function. Findings are discussed in relation to developing a new model of ACT that also includes the role of preattentive processes and dual-task coordination when exploring the effects of anxiety on task performance.

Input-orientated data envelopment analysis framework for measuring and decomposing economic, environmental and ecological efficiency : an application to OECD agriculture

This paper presents an input-orientated data envelopment analysis (DEA) framework which allows the measurement and decomposition of economic, environmental and ecological efficiency levels in agricultural production across different countries. Economic, environmental and ecological optimisations search for optimal input combinations that minimise total costs, total amount of nutrients, and total amount of cumulative exergy contained in inputs respectively. The application of the framework to an agricultural dataset of 30 OECD countries revealed that (i) there was significant scope to make their agricultural production systemsmore environmentally and ecologically sustainable; (ii) the improvement in the environmental and ecological sustainability could be achieved by being more technically efficient and, even more significantly, by changing the input combinations; (iii) the rankings of sustainability varied significantly across OECD countries within frontier-based environmental and ecological efficiency measures and between frontier-based measures and indicators.

Reproductive health : findings from the Australian Longitudinal Study on Women’s Health. Chapter 3: Use of contraception

Chapter 3: Use of contraception. p15-32 Key findings: This section examines trends in the use of contraception between 1996 and 2006 by women who participated in the surveys for the 1973-1978 cohort of the Australian Longitudinal Study on Women’s Health. 1. The oral contraceptive pill was the most commonly used method of contraception at each survey, but its use decreased over time. 2.Of women who consistently used contraception, 40% used the oral contraceptive pill as their only method of contraception in at least three out of four surveys. 3. The proportion of women using condoms as their only method of contraception remained steady over time (15-18%) but only 3% of all women used condoms only at every survey. 4. The proportion of women using both condoms and the oral contraceptive pill remained steady at 13-14% of all women from Survey 1 to 3, but decreased to 8% of all women at Survey 4. 5. The use of methods other than the oral contraceptive pill and/or condoms increased at Survey 4. 6. The proportion of women using an implant (e.g. Implanon) remained steady between Surveys 3 and 4, with 3% of women using an implant only. Around one third of implant users at Survey 3 continued to use this method at Survey 4. 7. The main reasons for not using contraception at Surveys 3 and 4 were pregnancy, trying to conceive, or no male sexual partners. 8. Women who used contraception were more likely to be in de facto relationships or single, be up to date with Pap tests and have had two or more births. 9. Women who did not use contraception were more likely to be non-drinkers and/or do low levels of exercise, have had one birth and have experienced miscarriage. 10. Contraception changed in expected ways according to reproductive events: women who reported only miscarriages between surveys also stopped using contraception in the same period; most women who did not report reproductive events continued to use the same method of contraception; and women who had a termination tended to switch methods.

Reproductive health: findings from the Australian Longitudinal Study on Women’s Health. Chapter 5: fertility and infertility

Chapter 5: Fertility and infertility. p52-70. This section describes patterns of fertility across Surveys 1 to 4 among the cohort of women who were born in 1973-1978. This section includes the examination of pregnancy outcomes including both live births and pregnancy losses (stillbirths, miscarriages, terminations and ectopic pregnancies). This section also examines the prevalence of self-reported problems with fertility and whether these women sought advice and/or treatment. As women age they are more likely to experience infertility and, with little other data available, the ALSWH provides an important opportunity to examine this problem and the related use of health services. 1. Pregnancy losses are common. Half of the women who report a pregnancy outcome at Survey 4 have experienced a pregnancy loss. 2. More than one third (39%) of women who have experienced a live birth by Survey 4 have also experienced a pregnancy loss. 3. For every ten women aged 28-33 years in 2006: four women had not had been pregnant, five women had a live birth (with or without a recognised pregnancy loss), and one woman had a recognised pregnancy loss only. 4. Among women who had tried to conceive or had been pregnant, one-in-six had experienced infertility. (i.e. tried unsuccessfully to get pregnant for 12 months or more) 5. The most significant factors associated with having infertility, seeking advice and using treatment were: polycystic ovary syndrome, endometriosis and miscarriage. 6. Of the women who reported infertility, two-thirds sought advice but only half used treatment. 7. Most of the women who used fertility treatment had used low cost and non-invasive methods.

Improving the efficiency of RFID authentication with pre-computation

Security of RFID authentication protocols has received considerable interest recently. However, an important aspect of such protocols that has not received as much attention is the efficiency of their communication. In this paper we investigate the efficiency benefits of pre-computation for time-constrained applications in small to medium RFID networks. We also outline a protocol utilizing this mechanism in order to demonstrate the benefits and drawbacks of using thisapproach. The proposed protocol shows promising results as it is able to offer the security of untraceableprotocols whilst only requiring the time comparable to that of more efficient but traceable protocols.

Agricultural biodiversity, farm level technical efficiency and conservation benefits : an empirical investigation

The issues involved in agricultural biodiversity are important and interesting areas for the application of economic theory. However, very little theoretical and empirical work has been undertaken to understand the benefits of conserving agricultural biodiversity. Accordingly, the main objectives of this PhD thesis are to: (1) Investigate farmers’ valuation of agricultural biodiversity; (2) Identify factors influencing farmers’ demand for agricultural biodiversity; (3) Examine farmers’ demand for biodiversity rich farming systems; (4) Investigate the relationship between agricultural biodiversity and farm level technical efficiency. This PhD thesis investigates these issues by using primary data in small-scale farms, along with secondary data from Sri Lanka. The overall findings of the thesis can be summarized as follows. Firstly, owing to educational and poverty issues of those being interviewed, some policy makers in developed countries question whether non-market valuation techniques such as Choice Experiment (CE) can be applied to developing countries such as Sri Lanka. The CE study in this thesis indicates that carefully designed and pre-tested nonmarket valuation techniques can be applied in developing countries with a high level of reliability. The CE findings support the priori assumption that small-scale farms and their multiple attributes contribute positively and significantly to the utility of farm families in Sri Lanka. Farmers have strong positive attitudes towards increasing agricultural biodiversity in rural areas. This suggests that these attitudes can be the basis on which appropriate policies can be introduced to improve agricultural biodiversity. Secondly, the thesis identifies the factors which influence farmers’ demand for agricultural biodiversity and farmers’ demands on biodiversity rich farming systems. As such they provide important tools for the implementation of policies designed to avoid the loss agricultural biodiversity which is shown to be a major impediment to agricultural growth and sustainable development in a number of developing countries. The results illustrate that certain key household, market and other characteristics (such as agricultural subsidies, percentage of investment of owned money and farm size) are the major determinants of demand for agricultural biodiversity on small-scale farms. The significant household characteristics that determine crop and livestock diversity include household member participation on the farm, off-farm income, shared labour, market price fluctuations and household wealth. Furthermore, it is shown that all the included market characteristics as well as agricultural subsidies are also important determinants of agricultural biodiversity. Thirdly, it is found that when the efficiency of agricultural production is measured in practice, the role of agricultural biodiversity has rarely been investigated in the literature. The results in the final section of the thesis show that crop diversity, livestock diversity and mix farming system are positively related to farm level technical efficiency. In addition to these variables education level, number of separate plots, agricultural extension service, credit access, membership of farm organization and land ownerships are significant and direct policy relevant variables in the inefficiency model. The results of the study therefore have important policy implications for conserving agricultural biodiversity in Sri Lanka.

Analysis of environmental efficiency variation : a materials balance approach

Recent literature has argued that environmental efficiency (EE), which is built on the materials balance (MB) principle, is more suitable than other EE measures in situations where the law of mass conversation regulates production processes. In addition, the MB-based EE method is particularly useful in analysing possible trade-offs between cost and environmental performance. Identifying determinants of MB-based EE can provide useful information to decision makers but there are very few empirical investigations into this issue. This article proposes the use of data envelopment analysis and stochastic frontier analysis techniques to analyse variation in MB-based EE. Specifically, the article develops a stochastic nutrient frontier and nutrient inefficiency model to analyse determinants of MB-based EE. The empirical study applies both techniques to investigate MB-based EE of 96 rice farms in South Korea. The size of land, fertiliser consumption intensity, cost allocative efficiency, and the share of owned land out of total land are found to be correlated with MB-based EE. The results confirm the presence of a trade-off between MB-based EE and cost allocative efficiency and this finding, favouring policy interventions to help farms simultaneously achieve cost efficiency and MP-based EE.

Improving the efficiency of high power piezoelectric transducers for industrial applications

Most high-power ultrasound applications are driven by two-level inverters. However, the broad spectral content of the two-level pulse results in undesired harmonics that can decrease the performance of the system significantly. On the other hand, it is crucial to excite the piezoelectric devices at their main resonant frequency in order to have maximum energy conversion. Therefore a high-quality, low-distorted power signal is needed to excite the high-power piezoelectric transducer at its resonant frequency. This study proposes an efficient approach to develop the performance of high-power ultrasonic applications using multilevel inverters along with a frequency estimation algorithm. In this method, the resonant frequencies are estimated based on relative minimums of the piezoelectric impedance frequency response. The algorithm follows the resonant frequency variation and adapts the multilevel inverter reference frequency to drive an ultrasound transducer at high power. Extensive simulation and experimental results indicate the effectiveness of the proposed approach.