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Biomedical subjects

R McDermott

Publications and source records attributed to R McDermott.

At least 19 recordsLinked to original sources
PubMed2006

Measurement of the entanglement of two superconducting qubits via state tomography.

Demonstration of quantum entanglement, a key resource in quantum computation arising from a nonclassical correlation of states, requires complete measurement of all states in varying bases. By using simultaneous measurement and state tomography, we demonstrated entanglement between two solid-state qubits. Single qubit operations and capacitive coupling between two super-conducting phase qubits were used to generate a Bell-type state. Full two-qubit tomography yielded a density matrix showing an entangled state with fidelity up to 87%. Our results demonstrate a high degree of unitary control of the system, indicating that larger implementations are within reach.

Journal Article↗
PubMed2006

Educating to improve population health outcomes in chronic disease: an innovative workforce initiative across remote, rural and Indigenous communities in northern Australia.

INTRODUCTION: Like Indigenous populations in other countries, an epidemic of chronic disease has swept across Australia's Indigenous communities in the past decade. The Northern Territory and Queensland health departments initiated preventable chronic disease strategies in 1999 and 2001, respectively. Yet finding innovative ways to translate this to the health workforce was challenging. Through support from the Australian Government, three universities, two health departments and two Indigenous organisations worked in partnership to improve workforce capacity in remote and rural communities through innovative education. METHODS: The methods included: (i) a training needs analysis consisting of 76 semi-structured interviews with key informants, and 35 surveys of remote staff; (ii) a literature and resource review; (iii) the development of a curriculum framework using: the existing competencies and standards across the health disciplines; the identified workforce needs; and what the workforce can impact upon; (iv) a multidisciplinary workshop with 35 educators across northern Australia that resulted in the basis for agreement of the final curriculum content and framework; (v) the development of a chronic disease self-assessment tool that was piloted with remote health staff; (vi) an assisted integration process for key stakeholders. An evaluation framework was also developed, as a separate project, in conjunction with the project partners during this time. RESULTS: This project identified that a paradigm shift is required in the way in which we educate the entire health workforce to deal effectively with the impact of chronic disease across remote, rural and Indigenous populations. In particular a need was found to educate the educators in the chronic care model and in using a population health approach. The training needs analysis identified very little difference between the education and training needs across the rural and remote health disciplines; it was perceived that they managed chronic disease fairly well yet found prevention and early detection to be at the 'hard end'. The main barriers identified were the demands of acute care over chronic disease management, compounded by high workforce turnover in remote areas. The curriculum framework, in particular the domains of remote practice, is being used by several Australian universities, health departments and non-government organisations in adapting their existing or new education programs. The self-assessment tool was based on the curriculum outcomes and was piloted in 2005 and found to be very useful for pre- and post-training purposes and as a discussion starter for all disciplines and groups. CONCLUSIONS: A practical curriculum framework now exists to integrate a population health approach for the prevention and early detection of chronic disease when educating the primary healthcare workforce. It is relevant to all health disciplines and is flexible in that it can be adapted, or adopted, depending on the educational needs of the disciplinary group. It is being imbedded into numerous undergraduate, postgraduate, and professional development programs in Australia. It includes: the core learning outcomes expected of any workforce, resources, and a self-assessment tool in chronic disease. These tools are assisting educators in the required paradigm shift required of the workforce to alter the single disease based practice model towards a comprehensive and integrated population based approach required for the workforce in the 21st century.

Chronic Disease↗
PubMed2006

State tomography of capacitively shunted phase qubits with high fidelity.

We introduce a new design concept for superconducting phase quantum bits (qubits) in which we explicitly separate the capacitive element from the Josephson tunnel junction for improved qubit performance. The number of two-level systems that couple to the qubit is thereby reduced by an order of magnitude and the measurement fidelity improves to 90%. This improved design enables the first demonstration of quantum state tomography with superconducting qubits using single-shot measurements.

Journal Article↗
PubMed2006

Coherent state evolution in a superconducting qubit from partial-collapse measurement.

Measurement is one of the fundamental building blocks of quantum-information processing systems. Partial measurement, where full wavefunction collapse is not the only outcome, provides a detailed test of the measurement process. We introduce quantum-state tomography in a superconducting qubit that exhibits high-fidelity single-shot measurement. For the two probabilistic outcomes of partial measurement, we find either a full collapse or a coherent yet nonunitary evolution of the state. This latter behavior explicitly confirms modern quantum-measurement theory and may prove important for error-correction algorithms in quantum computation.

Journal Article↗
PubMed2005

Decoherence in Josephson qubits from dielectric loss.

Dielectric loss from two-level states is shown to be a dominant decoherence source in superconducting quantum bits. Depending on the qubit design, dielectric loss from insulating materials or the tunnel junction can lead to short coherence times. We show that a variety of microwave and qubit measurements are well modeled by loss from resonant absorption of two-level defects. Our results demonstrate that this loss can be significantly reduced by using better dielectrics and fabricating junctions of small area . With a redesigned phase qubit employing low-loss dielectrics, the energy relaxation rate has been improved by a factor of 20, opening up the possibility of multiqubit gates and algorithms.

Journal Article↗
PubMed2005

Simultaneous state measurement of coupled Josephson phase qubits.

One of the many challenges of building a scalable quantum computer is single-shot measurement of all the quantum bits (qubits). We have used simultaneous single-shot measurement of coupled Josephson phase qubits to directly probe interaction of the qubits in the time domain. The concept of measurement crosstalk is introduced, and we show that its effects are minimized by careful adjustment of the timing of the measurements. We observe the antiphase oscillation of the two-qubit 01 and 10 states, consistent with quantum mechanical entanglement of these states, thereby opening the possibility for full characterization of multiqubit gates and elementary quantum algorithms.

Journal Article↗
PubMed2005

The metabolic syndrome and changing relationship between blood pressure and insulin with age, as observed in Aboriginal and Torres Strait Islander peoples.

AIMS: To determine the prevalence of the metabolic syndrome (MS) among Aboriginal and Torres Strait Islander peoples. A further objective was to investigate the relationships between fasting insulin and blood pressure (BP) within these groups with increasing age. METHODS: A cross-sectional population-based study included 369 Torres Strait Islanders (residing in Torres Strait and Far North Queensland), and 675 Aborigines from central Australia. Data necessary for classification of MS was collected, including fasting and 2-h glucose and insulin, urinary albumin and creatinine, anthropometric measurements, BP, serum lipids. RESULTS: The ATPIII criteria classified 43% of Torres Strait Islanders and 44% of Aborigines with MS, whereas 32 and 28%, respectively, had the MS according to WHO criteria. Agreement between the two criteria was only modest (kappa coefficient from 0.28 to 0.57). Factor analyses indicated no cluster including both insulin and BP in either population. Significant correlations (P < 0.05) [adjusted for gender, body mass index (BMI) and waist circumference] were observed between BP and fasting insulin: a positive correlation for Torres Strait Islanders aged 15-29 years, and an inverse correlation for Aborigines aged 40 years and older. CONCLUSION: Torres Strait Islanders and Aborigines had very high prevalences of the MS. Specific population characteristics (high prevalences of central obesity, dyslipidaemia, renal disease) may make the WHO definition preferable to the ATPIII definition in these population groups. The poor agreement between criteria suggests a more precise definition of the metabolic syndrome that is applicable across populations is required. This study showed an inverse relationship with age for the correlation of BP and fasting insulin.

Adolescent↗
PubMed2004

Observation of quantum oscillations between a Josephson phase qubit and a microscopic resonator using fast readout.

We have detected coherent quantum oscillations between Josephson phase qubits and critical-current fluctuators by implementing a new state readout technique that is an order of magnitude faster than previous methods. These results reveal a new aspect of the quantum behavior of Josephson junctions, and they demonstrate the means to measure two-qubit interactions in the time domain. The junction-fluctuator interaction also points to a possible mechanism for decoherence and reduced fidelity in superconducting qubits.

Journal Article↗
PubMed2004

Sustaining better diabetes care in remote indigenous Australian communities.

PROBLEM: Inhabitants of Torres Strait Islands have the highest prevalence of diabetes in Australia and many preventable complications. In 1999, a one year randomised cluster trial showed improved diabetes care processes and reduced admissions to hospital when local indigenous health workers used registers, recall and reminder systems, and basic diabetes care plans, supported by a specialist outreach service. This study looked at whether those improvements were sustained two years after the end of the trial. DESIGN: Three year follow up clinical audit of 21 primary health care centres, and review of admissions to hospital in the previous 12 months. BACKGROUND AND SETTING: Remote indigenous communities in far north east Australia, population about 9600, including 921 people with diabetes. KEY MEASURES FOR IMPROVEMENT: Number of people on registers, care processes (regular measures of weight, blood pressure, haemoglobin A1c, urinary protein concentration, and concentrations of serum lipids and creatinine), appropriate clinical interventions (drug treatment and vaccinations), and intermediate patient outcome measures (weight, blood pressure, and glycaemic control). Admissions to hospital. STRATEGIES FOR CHANGE: Audit and feedback to clinicians and managers; provision of clinical guidelines and a clear management structure; workshops and training. EFFECTS OF CHANGE: The number of people on registers increased from 555 in 1999 to 921 in 2002. Most care processes and clinical interventions improved. The proportion of people with good glycaemic control (haemoglobin A1c 7%) increased from 18% to 25% in line with increased use of insulin (from 7% to 16%). The proportion of those with well controlled hypertension (< 140/90) increased from 40% to 64%. The proportion admitted to hospital with a diabetes related condition fell from 25% to 20%. Mean weight increased from 87 kg to 91 kg. LESSONS LEARNT: In remote settings, appropriate management structures and clinical support for people with diabetes can lead to improvements in care processes, control of blood pressure, and preventable complications that result in admission to hospital. Control of weight and glycaemia are more difficult and requires more active community engagement. Priorities now include increasing the availability and affordability of good food, achieving weight loss, and increasing appropriate use of hypoglycaemic agents, including insulin.

Adult↗
PubMed2003

Children's bicycle helmet use and injuries in Hillsborough County, Florida before and after helmet legislation.

The purpose of this research was to explore the changes in children's bicycle helmet use and motor vehicle bicycle related injuries in Hillsborough County, Florida before and after passage of the Florida's bicycle helmet law for children under the age of 16. The results show a significant increase in bicycle helmet use among children, ages 5-13, in the post-law years compared with the pre-law years. Also, there has been a significant decline in the rates of bicycle related motor vehicle injuries among children in the post-law years compared with the pre-law years. Although there have been complementary educational and outreach activities in the county to support helmet use, it appears that the greatest increase in use occurred after the passage of the helmet law. It is recommended that educational efforts continue to sustain helmet use rates and decreases in injuries.

Accidents, Traffic↗
PubMed2003

Predictors of the prevalence of bacterial STI among young disadvantaged Indigenous people in north Queensland, Australia.

OBJECTIVE: To identify sexually transmitted infections in rural and remote Indigenous communities in north eastern Australia and examine factors that may influence prevalence. METHODS: A cross sectional survey of 26 Aboriginal and Torres Strait Islander communities in northern Queensland was carried out. 3313 people (2862 Indigenous) aged 15 years and over resident in participating communities during the period March 1998 to December 2000. The main outcome measures were community and population prevalence of chlamydia and gonorrhoea and independently associated risk factors. RESULTS: A total of 238 cases of chlamydia, 66 cases of gonorrhoea, and 37 cases of co-infection were detected among Indigenous participants. Prevalence of chlamydia and/or gonorrhoea ranged from 23.0% among 15-19 year olds to 3.5% among those 40 years and older. In the adjusted analysis younger age, female sex, lower socioeconomic status, the use of alcohol and tobacco, and the structure of community health services were independently associated with a higher prevalence of bacterial STI. CONCLUSION: This study highlights the need for improved STI control in north Queensland Indigenous communities through strategies to improve the reach and accessibility of primary healthcare services.

Adolescent↗
PubMed2002

Diabetes and impaired glucose tolerance in Aboriginal Australians: prevalence and risk.

The prevalence and risk of having impaired glucose tolerance (IGT) and diabetes was estimated relative to body mass index (BMI) among Australian Aboriginal people. A stratified analysis was undertaken of community screening data. Measures included fasting and 2-h glucose concentrations, and BMI (five strata: <22, 22-24.9, 25-29.9, 30-34.9 and >/=35 kg/m(2)). Age was stratified into three groups: 15-34.9, 35-44.9, and >/=45 years. Participants were men and women, ages 15-94 years (n=2626). The prevalence of IGT and diabetes, respectively, adjusted for age and BMI, was 139 and 142 cases/1000 persons among men, and 157 and 152 cases/1000 persons among women. Odds ratios (95% CI) for IGT and diabetes for increasing BMI strata >/=22 kg/m(2) ranged from 1.7 (1.0 to 2.9) to 5.1 (2.4-10.5) for IGT, and from 2.0 (1.2-3.5) to 6.1 (3.3-11.1) for diabetes. For IGT and diabetes, across genders, the population attributable risk percentages (95% CI) for BMI >/=22 kg/m(2) were 34.1% (26.2-41.9%) for IGT, and 46.4% (38.5-54.5%) for diabetes. Diabetes and IGT have reached epidemic proportions among Australian Aboriginal people. An urgent need exists for programmes to reduce the prevalence of diabetes risk factors, especially BMI of 22 kg/m(2) or more, a limit lower than advocated for Euro-American populations.

Adolescent↗
PubMed2000

Ultrasensitive magnetic biosensor for homogeneous immunoassay.

A technique is described for specific, sensitive, quantitative, and rapid detection of biological targets by using superparamagnetic nanoparticles and a "microscope" based on a high-transition temperature dc superconducting quantum interference device (SQUID). In this technique, a mylar film to which the targets have been bound is placed on the microscope. The film, at room temperature and atmospheric pressure, is typically 40 micrometer from the SQUID, which is at 77 K in a vacuum. A suspension of magnetic nanoparticles carrying antibodies directed against the target is added to the mixture in the well, and 1-s pulses of magnetic field are applied parallel to the SQUID. In the presence of this aligning field the nanoparticles develop a net magnetization, which relaxes when the field is turned off. Unbound nanoparticles relax rapidly by Brownian rotation and contribute no measurable signal. Nanoparticles that are bound to the target on the film are immobilized and undergo Néel relaxation, producing a slowly decaying magnetic flux, which is detected by the SQUID. The ability to distinguish between bound and unbound labels allows one to run homogeneous assays, which do not require separation and removal of unbound magnetic particles. The technique has been demonstrated with a model system of liposomes carrying the FLAG epitope. The SQUID microscope requires no more than (5 +/- 2) x 10(4) magnetic nanoparticles to register a reproducible signal.

Biosensing Techniques↗
PubMed2000

Increase in prevalence of obesity and diabetes and decrease in plasma cholesterol in a central Australian aboriginal community.

OBJECTIVE: To document change in prevalence of obesity, diabetes and other cardiovascular disease (CVD) risk factors, and trends in dietary macronutrient intake, over an eight-year period in a rural Aboriginal community in central Australia. DESIGN: Sequential cross-sectional community surveys in 1987, 1991 and 1995. SUBJECTS: All adults (15 years and over) in the community were invited to participate. In 1987, 1991 and 1995, 335 (87% of eligible adults), 331 (76%) and 304 (68%), respectively, were surveyed. MAIN OUTCOME MEASURES: Body mass index and waist: hip ratio; blood glucose level and glucose tolerance; fasting total and high density lipoprotein (HDL) cholesterol and triglyceride levels; and apparent dietary intake (estimated by the store turnover method). INTERVENTION: A community-based nutrition awareness and healthy lifestyle program, 1988-1990. RESULTS: At the eight-year follow-up, the odds ratios (95% CIs) for CVD risk factors relative to baseline were obesity, 1.84 (1.28-2.66); diabetes, 1.83 (1.11-3.03); hypercholesterolaemia, 0.29 (0.20-0.42); and dyslipidemia (high triglyceride plus low HDL cholesterol level), 4.54 (2.84-7.29). In younger women (15-24 years), there was a trembling in obesity prevalence and a four- to fivefold increase in diabetes prevalence. Store turnover data suggested a relative reduction in the consumption of refined carbohydrates and saturated fats. CONCLUSIONS: Interventions targeting nutritional factors alone are unlikely to greatly alter trends towards increasing prevalences of obesity and diabetes. In communities where healthy food choices are limited, the role of regular physical activity in improving metabolic fitness may also need to be emphasised.

Adolescent↗
PubMed2000

Albuminuria in Australian Aboriginal people: prevalence and associations with components of the metabolic syndrome.

AIMS/HYPOTHESIS: To examine the prevalence and associations with the metabolic syndrome of albuminuria among Australian Aboriginal people. METHODS: Early-morning urine specimens were collected as part of community-based risk factor surveys assessing the prevalence of diabetes and cardiovascular disease in eight remote communities, with a sample size of 1,075 people. Microalbuminuria was defined as urinary albumin : creatinine ratio 3.4-33.9 mg/mmol, macroalbuminuria as albumin: creatinine ratio equal to or greater than 34 mg/mmol. RESULTS: There were high prevalences of microalbuminuria (men 22.2 %, women 26.9 %) and of macroalbuminuria (men 10.4%, women 13.5%). There were highly statistically significant linear associations of microalbuminuria and macroalbuminuria with increasing number of coexisting components of the metabolic syndrome (hypertension, glucose intolerance, dyslipidaemia, insulin resistance, abdominal obesity): among people with zero, one, two and three to five of these conditions, respectively, prevalence of microalbuminuria was 16%, 20%, 36% and 32% (p < 0.001); prevalence of macroalbuminuria was 2%, 6%, 12% and 32% (p < 0.001). There were independent associations of microalbuminuria with hypertension (odds ratio, 95% confidence interval = 2.36, 1.63-3.42) and diabetes (2.10, 1.28-3.45): macroalbuminuria was independently associated with hypertension (6.39, 3.93-10.4), diabetes (3.49, 1.93-6.28) and abdominal obesity (4.56, 2.40-8.64) and had a weaker association with insulin resistance (1.99, 1.12-3.54). Dyslipidaemia and impaired glucose tolerance were neither independently associated with microalbuminuria or macroalbuminuria, nor was insulin resistance or abdominal obesity independently associated with microalbuminuria. CONCLUSION/INTERPRETATION: There was a strong clustering of albuminuria with components of the metabolic syndrome. Diabetes, hypertension and abdominal obesity are major contributors to high rates of albuminuria among Australian Aboriginal people.

Adolescent↗
PubMed2000

Endovascular management of rare sciatic artery aneurysm.

PURPOSE: To present a rare case of complete persistent sciatic artery aneurysm successfully treated by coil embolization and to suggest a new classification for this anomaly that encompasses both clinical and pathological factors. METHODS AND RESULTS: A 77-year-old female presented with sudden onset of sharp, throbbing left thigh and foot pain. A nontender 10.0- x 7.0-cm pulsatile mass was found over the inferolateral aspect of the left buttock on examination in the right lateral decubitus position. Angiography demonstrated a 6.9-cm sciatic artery aneurysm with the distal sciatic artery completely thrombosed. Before planned bypass grafting, the aneurysm and distal segment of the internal iliac artery were successfully embolized with coils through a left percutaneous approach. The patient's symptoms resolved with no deterioration in limb perfusion, and further revascularization was unnecessary. Postembolization imaging showed complete occlusion of the aneurysm, which has continued for 19 months. CONCLUSIONS: The application of endovascular techniques and surgical revascularization procedures provides numerous management options for the treatment of an aneurysmal persistent sciatic artery. This case demonstrates that clinical evaluation between staged procedures may obviate the need for further intervention.

Aged↗