Benchmarking an 11-qubit quantum computer

The field of quantum computing has grown from concept to demonstration devices over the past 20 years. Universal quantum computing offers efficiency in approaching problems of scientific and commercial interest, such as factoring large numbers, searching databases, simulating intractable models from quantum physics, and optimizing complex cost functions. Here, we present an 11-qubit fully-connected, programmable quantum computer in a trapped ion system composed of 13 ¹⁷¹Yb⁺ ions. We demonstrate average single-qubit gate fidelities of 99.5\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}%, average two-qubit-gate fidelities of 97.5\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}%, and SPAM errors of 0.7\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}%. To illustrate the capabilities of this universal platform and provide a basis for comparison with similarly-sized devices, we compile the Bernstein-Vazirani and Hidden Shift algorithms into our native gates and execute them on the hardware with average success rates of 78\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}% and 35\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}%, respectively. These algorithms serve as excellent benchmarks for any type of quantum hardware, and show that our system outperforms all other currently available hardware.

The growing complexity of quantum computing devices makes presents challenges for benchmarking their performance as previous, exhaustive approaches become infeasible. Here the authors characterise the quality of their 11-qubit device by successfully computing two quantum algorithms.

Effect of vitamin K on bone mineral density and fractures in adults: an updated systematic review and meta-analysis of randomised controlled trials

Vitamin K may affect bone mineral density and fracture incidence. Since publication of a previous systematic review the integrity of some of the previous evidence has been questioned and further trials have been published. Therefore an update to the systematic review was required.

INTRODUCTION

This systematic review was designed to assess the effectiveness of oral vitamin K supplementation for increasing bone mineral density and reducing fractures in adults.

METHODS

MEDLINE, EMBASE, CENTRAL, CINAHL, clinicaltrials.gov, and WHO-ICTRP were searched for eligible trials. Randomised controlled trials assessing oral vitamin K supplementation that assessed bone mineral density or fractures in adult populations were included. A total of 36 studies were identified. Two independent reviewers extracted data using a piloted extraction form.

RESULTS

For post-menopausal or osteoporotic patients, meta-analysis showed that the odds of any clinical fracture were lower for vitamin K compared to controls (OR, 0.72, 95%CI 0.55 to 0.95). Restricting the analysis to low risk of bias trials reduced the OR to 0.76 (95%CI, 0.58 to 1.01). There was no difference in vertebral fractures between the groups (OR 0.96, 95%CI 0.83 to 1.11). In the bone mineral density meta-analysis, percentage change from baseline at the lumbar spine was higher at 1 year (MD 0.93, 95%, CI - 0.02 to 1.89) and 2 years (MD 1.63%, 95%CI 0.10 to 3.16) for vitamin K compared to controls; however, removing trials at high risk of bias tended to result in smaller differences that were not statistically significant. At 6 months, it was higher in the hip (MD 0.42%, 95%CI 0.01 to 0.83) and femur (MD 0.29%, 95%CI 0.17 to 0.42). There was no significant difference at other anatomical sites.

CONCLUSIONS

For post-menopausal or osteoporotic patients, there is no evidence that vitamin K affects bone mineral density or vertebral fractures; it may reduce clinical fractures; however, the evidence is insufficient to confirm this. There are too few trials to draw conclusions for other patient groups.

Implementation and evaluation of nationwide scale-up of the Surgical Safety Checklist

Background

The WHO Surgical Safety Checklist improves surgical outcomes, but evidence and theoretical frameworks for successful implementation in low‐income countries remain lacking. Based on previous research in Madagascar, a nationwide checklist implementation in Benin was designed and evaluated longitudinally.

Methods

This study had a longitudinal embedded mixed‐methods design. The well validated Consolidated Framework for Implementation Research (CFIR) was used to structure the approach and evaluate the implementation. Thirty‐six hospitals received 3‐day multidisciplinary training and 4‐month follow‐up. Seventeen hospitals were sampled purposively for evaluation at 12–18 months. The primary outcome was sustainability of checklist use at 12–18 months measured by questionnaire. Secondary outcomes were CFIR‐derived implementation outcomes, measured using the WHO Behaviourally Anchored Rating Scale (WHOBARS), safety questionnaires and focus groups.

Results

At 12–18 months, 86·0 per cent of participants (86 of 100) reported checklist use compared with 31·1 per cent (169 of 543) before training and 88·8 per cent (158 of 178) at 4 months. There was high‐fidelity use (median WHOBARS score 5·0 of 7; use of basic safety processes ranged from 85·0 to 99·0 per cent), and high penetration shown by a significant improvement in hospital safety culture (adapted Human Factors Attitude Questionnaire scores of 76·7, 81·1 and 82·2 per cent before, and at 4 and 12–18 months after training respectively; P < 0·001). Acceptability, adoption, appropriateness and feasibility scored 9·6–9·8 of 10. This approach incorporated 31 of 36 CFIR implementation constructs successfully.

Conclusion

This study shows successfully sustained nationwide checklist implementation using a validated implementation framework.

Implementation works

Interventional management of hyperhidrosis in secondary care: a systematic review

BACKGROUND

Hyperhidrosis is uncontrollable excessive sweating, which occurs at rest, regardless of temperature. The symptoms of hyperhidrosis can significantly affect quality of life.

OBJECTIVES

To undertake a systematic review of the clinical effectiveness and safety of treatments available in secondary care for the management of primary hyperhidrosis.

METHODS

Fifteen databases (including trial registers) were searched to July 2016 to identify studies of secondary-care treatments for primary hyperhidrosis. For each intervention randomized controlled trials (RCTs) were included where available; where RCT evidence was lacking, nonrandomized trials or large prospective case series were included. Outcomes of interest included disease severity, sweat rate, quality of life, patient satisfaction and adverse events. Trial quality was assessed using a modified version of the Cochrane Risk of Bias tool. Results were pooled in pairwise meta-analyses where appropriate, otherwise a narrative synthesis was presented.

RESULTS

Fifty studies were included in the review: 32 RCTs, 17 nonrandomized trials and one case series. The studies varied in terms of population, intervention and methods of outcome assessment. Most studies were small, at high risk of bias and poorly reported. The interventions assessed were iontophoresis, botulinum toxin (BTX) injections, anticholinergic medications, curettage and newer energy-based technologies that damage the sweat gland.

CONCLUSIONS

The evidence for the effectiveness and safety of treatments for primary hyperhidrosis is limited overall, and few firm conclusions can be drawn. However, there is moderate-quality evidence to support the use of BTX for axillary hyperhidrosis. A trial comparing BTX with iontophoresis for palmar hyperhidrosis is warranted.

Importance of tau in cognitive decline as revealed by developmental exposure to lead

Previous reports by us have determined that developmental exposure to the heavy metal lead (Pb) resulted in cognitive impairment in aging wildtype mice, and a latent induction in biomarkers associated with both the tau and amyloid pathways. However, the relationship between these two pathways and their correlation to cognitive performance needs to be scrutinized. Here, we investigated the impact of developmental Pb (0.2%) exposure on the amyloid and tau pathways in a transgenic mouse model lacking the tau gene. Cognitive function, and levels of intermediates in the amyloid and tau pathways following postnatal Pb exposure were assessed on young adult and mature transgenic mice. No significant difference in behavioral performance, amyloid precursor protein (APP), or amyloid beta (Aβ) levels was observed in transgenic mice exposed to Pb. Regulators of the tau pathway were impacted by the absence of tau, but no additional change was imparted by Pb exposure. These results revealed that developmental Pb exposure does not cause cognitive decline or change the expression of the amyloid pathway in the absence of tau. The essentiality of tau to mediate cognitive decline by environmental perturbations needs further investigation.

A multicentre study of long-term follow-up and owner satisfaction following enucleation in horses

BACKGROUND

Horses are reported to return to a variety of disciplines following unilateral enucleation; however, owners of horses with ocular disease are frequently reluctant to consider the procedure. There is little published information investigating owners' attitudes towards, and satisfaction following, enucleation.

OBJECTIVES

To investigate the hypotheses: 1) horses return to their previous level of work following unilateral enucleation and 2) their owners are satisfied with the post-operative outcome.

STUDY DESIGN

Retrospective case series with cross-sectional survey.

METHODS

Clinical records from eight equine referral centres in the United Kingdom were reviewed to identify horses that underwent enucleation between August 2006 and March 2015. Owner questionnaires were completed to corroborate information provided by medical records and obtain information on client perceptions.

RESULTS

A total of 170 cases were identified and 119 owner questionnaires completed. The most frequent primary uses of horses in the study were pleasure/leisure riding, showjumping and dressage, with 25.2% (n = 30) of horses used for competition. Following enucleation, 77.3% (n = 92) of horses were performing at an equivalent or higher level than prior to enucleation and 60.0% (n = 18/30) of competition horses were competing at an equivalent or higher level. Complications related to the surgical site (predominantly mild post-operative swelling) were reported in 3.7% of cases and nonocular complications in 3.7% of cases. Of owners who reported being concerned or very concerned about certain factors prior to surgery, ≥86.8% reported that these factors caused little or no issue post-surgery. Most owners, 90.8% (n = 108) were pleased with the outcome following surgery, with 21.3% (n = 23/108) wishing the procedure had been undertaken sooner.

MAIN LIMITATIONS

Retrospective data collection from clinical records and the potential for recall bias.

CONCLUSIONS

Horses can return successfully to a variety of disciplines following enucleation. Owners are satisfied with the outcome and pleased that enucleation was performed.

Effect of MTA particle size on periapical healing

AIM

To examine the effect of reduction in MTA particle size on dento-alveolar and osseous healing in dogs.

METHODOLOGY

Root canals of 24 mandibular premolars in four 2-year-old beagles were prepared and filled with gutta-percha and sealer. Two to four weeks later, during periapical surgery, the root-end cavity preparations in these teeth were filled with either grey ProRoot MTA or modified (reduced particle sizes with faster setting time) MTA. The animals were sacrificed 4 months later. Degrees of inflammation, type of inflammatory cells, fibrous connective tissue adjacent to the root-end filling materials, cementum formation over the resected roots and root-end filling materials and bone healing were examined. Data were analysed using the McNemar test.

RESULTS

No significant differences in healing of periapical tissues were found when comparing ProRoot MTA to a modified MTA containing reduced particle sizes.

CONCLUSION

Reducing the particle sizes of MTA did not impact its biological properties.